From 1b2439dbb703ae8d95a9ce7ece6b7800b80f41f0 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Fri, 15 Aug 2008 15:29:38 -0700 Subject: debug: add notifier chain debugging during some development we suspected a case where we left something in a notifier chain that was from a module that was unloaded already... and that sort of thing is rather hard to track down. This patch adds a very simple sanity check (which isn't all that expensive) to make sure the notifier we're about to call is actually from either the kernel itself of from a still-loaded module, avoiding a hard-to-chase-down crash. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar --- kernel/notifier.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel') diff --git a/kernel/notifier.c b/kernel/notifier.c index 823be11..143fdd7 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -21,6 +21,10 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); static int notifier_chain_register(struct notifier_block **nl, struct notifier_block *n) { + if (!kernel_text_address((unsigned long)n->notifier_call)) { + WARN(1, "Invalid notifier registered!"); + return 0; + } while ((*nl) != NULL) { if (n->priority > (*nl)->priority) break; @@ -34,6 +38,10 @@ static int notifier_chain_register(struct notifier_block **nl, static int notifier_chain_cond_register(struct notifier_block **nl, struct notifier_block *n) { + if (!kernel_text_address((unsigned long)n->notifier_call)) { + WARN(1, "Invalid notifier registered!"); + return 0; + } while ((*nl) != NULL) { if ((*nl) == n) return 0; @@ -82,6 +90,14 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl, while (nb && nr_to_call) { next_nb = rcu_dereference(nb->next); + +#ifdef CONFIG_DEBUG_NOTIFIERS + if (!kernel_text_address((unsigned long)nb->notifier_call)) { + WARN(1, "Invalid notifier called!"); + nb = next_nb; + continue; + } +#endif ret = nb->notifier_call(nb, val, v); if (nr_calls) -- cgit v1.1 From fb822db465bd9fd4208eef1af4490539b236c54e Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 20 Aug 2008 11:17:40 +0200 Subject: softlockup: increase hung tasks check from 2 minutes to 8 minutes Andrew says: > Seems that about 100% of the reports we get of this warning triggering > are sys_sync, transaction commit, etc. increase the timeout. If it still triggers for people, we can kill it. Signed-off-by: Ingo Molnar --- kernel/softlockup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/softlockup.c b/kernel/softlockup.c index b75b492..17a0580 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -164,7 +164,7 @@ unsigned long __read_mostly sysctl_hung_task_check_count = 1024; /* * Zero means infinite timeout - no checking done: */ -unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120; +unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480; unsigned long __read_mostly sysctl_hung_task_warnings = 10; -- cgit v1.1 From ab7476cf76e560f0efda2a631a70aabe93009025 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Fri, 15 Aug 2008 15:29:38 -0700 Subject: debug: add notifier chain debugging, v2 - unbreak ia64 (and powerpc) where function pointers dont point at code but at data (reported by Tony Luck) [ mingo@elte.hu: various cleanups ] Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar --- kernel/extable.c | 16 ++++++++++++++++ kernel/notifier.c | 10 +--------- 2 files changed, 17 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/extable.c b/kernel/extable.c index a26cb2e..adf0cc9 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -66,3 +66,19 @@ int kernel_text_address(unsigned long addr) return 1; return module_text_address(addr) != NULL; } + +/* + * On some architectures (PPC64, IA64) function pointers + * are actually only tokens to some data that then holds the + * real function address. As a result, to find if a function + * pointer is part of the kernel text, we need to do some + * special dereferencing first. + */ +int func_ptr_is_kernel_text(void *ptr) +{ + unsigned long addr; + addr = (unsigned long) dereference_function_descriptor(ptr); + if (core_kernel_text(addr)) + return 1; + return module_text_address(addr) != NULL; +} diff --git a/kernel/notifier.c b/kernel/notifier.c index 143fdd7..0f39e39 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -21,10 +21,6 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); static int notifier_chain_register(struct notifier_block **nl, struct notifier_block *n) { - if (!kernel_text_address((unsigned long)n->notifier_call)) { - WARN(1, "Invalid notifier registered!"); - return 0; - } while ((*nl) != NULL) { if (n->priority > (*nl)->priority) break; @@ -38,10 +34,6 @@ static int notifier_chain_register(struct notifier_block **nl, static int notifier_chain_cond_register(struct notifier_block **nl, struct notifier_block *n) { - if (!kernel_text_address((unsigned long)n->notifier_call)) { - WARN(1, "Invalid notifier registered!"); - return 0; - } while ((*nl) != NULL) { if ((*nl) == n) return 0; @@ -92,7 +84,7 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl, next_nb = rcu_dereference(nb->next); #ifdef CONFIG_DEBUG_NOTIFIERS - if (!kernel_text_address((unsigned long)nb->notifier_call)) { + if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) { WARN(1, "Invalid notifier called!"); nb = next_nb; continue; -- cgit v1.1 From 6918bc5c830e890681eabb3c6cb6b8d117a52d14 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 23 Sep 2008 15:33:41 +0200 Subject: lockstat: fixup signed division Some recent modification to this code made me notice the little todo mark. Now that we have more elaborate 64-bit division functions this isn't hard. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 20dbcbf..8d3a6eba 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -470,11 +470,12 @@ static void seq_line(struct seq_file *m, char c, int offset, int length) static void snprint_time(char *buf, size_t bufsiz, s64 nr) { - unsigned long rem; + s64 div; + s32 rem; nr += 5; /* for display rounding */ - rem = do_div(nr, 1000); /* XXX: do_div_signed */ - snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, (int)rem/10); + div = div_s64_rem(nr, 1000, &rem); + snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10); } static void seq_time(struct seq_file *m, s64 time) -- cgit v1.1 From 38d47c1b7075bd7ec3881141bb3629da58f88dab Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Sep 2008 19:32:20 +0200 Subject: futex: rely on get_user_pages() for shared futexes On the way of getting rid of the mmap_sem requirement for shared futexes, start by relying on get_user_pages(). Signed-off-by: Peter Zijlstra Acked-by: Nick Piggin Signed-off-by: Ingo Molnar --- kernel/futex.c | 162 ++++++++++++++++++++++++++++----------------------------- 1 file changed, 80 insertions(+), 82 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 7d1136e..a4c39fa 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -161,6 +161,45 @@ static inline int match_futex(union futex_key *key1, union futex_key *key2) && key1->both.offset == key2->both.offset); } +/* + * Take a reference to the resource addressed by a key. + * Can be called while holding spinlocks. + * + */ +static void get_futex_key_refs(union futex_key *key) +{ + if (!key->both.ptr) + return; + + switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { + case FUT_OFF_INODE: + atomic_inc(&key->shared.inode->i_count); + break; + case FUT_OFF_MMSHARED: + atomic_inc(&key->private.mm->mm_count); + break; + } +} + +/* + * Drop a reference to the resource addressed by a key. + * The hash bucket spinlock must not be held. + */ +static void drop_futex_key_refs(union futex_key *key) +{ + if (!key->both.ptr) + return; + + switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { + case FUT_OFF_INODE: + iput(key->shared.inode); + break; + case FUT_OFF_MMSHARED: + mmdrop(key->private.mm); + break; + } +} + /** * get_futex_key - Get parameters which are the keys for a futex. * @uaddr: virtual address of the futex @@ -184,7 +223,6 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, { unsigned long address = (unsigned long)uaddr; struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; struct page *page; int err; @@ -210,98 +248,47 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, key->private.address = address; return 0; } - /* - * The futex is hashed differently depending on whether - * it's in a shared or private mapping. So check vma first. - */ - vma = find_extend_vma(mm, address); - if (unlikely(!vma)) - return -EFAULT; - /* - * Permissions. - */ - if (unlikely((vma->vm_flags & (VM_IO|VM_READ)) != VM_READ)) - return (vma->vm_flags & VM_IO) ? -EPERM : -EACCES; +again: + err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL); + if (err < 0) + return err; + + lock_page(page); + if (!page->mapping) { + unlock_page(page); + put_page(page); + goto again; + } /* * Private mappings are handled in a simple way. * * NOTE: When userspace waits on a MAP_SHARED mapping, even if * it's a read-only handle, it's expected that futexes attach to - * the object not the particular process. Therefore we use - * VM_MAYSHARE here, not VM_SHARED which is restricted to shared - * mappings of _writable_ handles. + * the object not the particular process. */ - if (likely(!(vma->vm_flags & VM_MAYSHARE))) { - key->both.offset |= FUT_OFF_MMSHARED; /* reference taken on mm */ + if (PageAnon(page)) { + key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */ key->private.mm = mm; key->private.address = address; - return 0; - } - - /* - * Linear file mappings are also simple. - */ - key->shared.inode = vma->vm_file->f_path.dentry->d_inode; - key->both.offset |= FUT_OFF_INODE; /* inode-based key. */ - if (likely(!(vma->vm_flags & VM_NONLINEAR))) { - key->shared.pgoff = (((address - vma->vm_start) >> PAGE_SHIFT) - + vma->vm_pgoff); - return 0; + } else { + key->both.offset |= FUT_OFF_INODE; /* inode-based key */ + key->shared.inode = page->mapping->host; + key->shared.pgoff = page->index; } - /* - * We could walk the page table to read the non-linear - * pte, and get the page index without fetching the page - * from swap. But that's a lot of code to duplicate here - * for a rare case, so we simply fetch the page. - */ - err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL); - if (err >= 0) { - key->shared.pgoff = - page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); - put_page(page); - return 0; - } - return err; -} + get_futex_key_refs(key); -/* - * Take a reference to the resource addressed by a key. - * Can be called while holding spinlocks. - * - */ -static void get_futex_key_refs(union futex_key *key) -{ - if (key->both.ptr == NULL) - return; - switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { - case FUT_OFF_INODE: - atomic_inc(&key->shared.inode->i_count); - break; - case FUT_OFF_MMSHARED: - atomic_inc(&key->private.mm->mm_count); - break; - } + unlock_page(page); + put_page(page); + return 0; } -/* - * Drop a reference to the resource addressed by a key. - * The hash bucket spinlock must not be held. - */ -static void drop_futex_key_refs(union futex_key *key) +static inline +void put_futex_key(struct rw_semaphore *fshared, union futex_key *key) { - if (!key->both.ptr) - return; - switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { - case FUT_OFF_INODE: - iput(key->shared.inode); - break; - case FUT_OFF_MMSHARED: - mmdrop(key->private.mm); - break; - } + drop_futex_key_refs(key); } static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval) @@ -385,6 +372,7 @@ static int refill_pi_state_cache(void) /* pi_mutex gets initialized later */ pi_state->owner = NULL; atomic_set(&pi_state->refcount, 1); + pi_state->key = FUTEX_KEY_INIT; current->pi_state_cache = pi_state; @@ -462,7 +450,7 @@ void exit_pi_state_list(struct task_struct *curr) struct list_head *next, *head = &curr->pi_state_list; struct futex_pi_state *pi_state; struct futex_hash_bucket *hb; - union futex_key key; + union futex_key key = FUTEX_KEY_INIT; if (!futex_cmpxchg_enabled) return; @@ -725,7 +713,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, struct futex_hash_bucket *hb; struct futex_q *this, *next; struct plist_head *head; - union futex_key key; + union futex_key key = FUTEX_KEY_INIT; int ret; if (!bitset) @@ -760,6 +748,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, spin_unlock(&hb->lock); out: + put_futex_key(fshared, &key); futex_unlock_mm(fshared); return ret; } @@ -773,7 +762,7 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared, u32 __user *uaddr2, int nr_wake, int nr_wake2, int op) { - union futex_key key1, key2; + union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; struct futex_hash_bucket *hb1, *hb2; struct plist_head *head; struct futex_q *this, *next; @@ -873,6 +862,8 @@ retry: if (hb1 != hb2) spin_unlock(&hb2->lock); out: + put_futex_key(fshared, &key2); + put_futex_key(fshared, &key1); futex_unlock_mm(fshared); return ret; @@ -886,7 +877,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, u32 __user *uaddr2, int nr_wake, int nr_requeue, u32 *cmpval) { - union futex_key key1, key2; + union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; struct futex_hash_bucket *hb1, *hb2; struct plist_head *head1; struct futex_q *this, *next; @@ -974,6 +965,8 @@ out_unlock: drop_futex_key_refs(&key1); out: + put_futex_key(fshared, &key2); + put_futex_key(fshared, &key1); futex_unlock_mm(fshared); return ret; } @@ -1220,6 +1213,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, retry: futex_lock_mm(fshared); + q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) goto out_release_sem; @@ -1360,6 +1354,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, queue_unlock(&q, hb); out_release_sem: + put_futex_key(fshared, &q.key); futex_unlock_mm(fshared); return ret; } @@ -1411,6 +1406,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, retry: futex_lock_mm(fshared); + q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) goto out_release_sem; @@ -1625,6 +1621,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, queue_unlock(&q, hb); out_release_sem: + put_futex_key(fshared, &q.key); futex_unlock_mm(fshared); if (to) destroy_hrtimer_on_stack(&to->timer); @@ -1671,7 +1668,7 @@ static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared) struct futex_q *this, *next; u32 uval; struct plist_head *head; - union futex_key key; + union futex_key key = FUTEX_KEY_INIT; int ret, attempt = 0; retry: @@ -1744,6 +1741,7 @@ retry_unlocked: out_unlock: spin_unlock(&hb->lock); out: + put_futex_key(fshared, &key); futex_unlock_mm(fshared); return ret; -- cgit v1.1 From 61270708ecf1cda148e84fbf6e0703ee5aa81814 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Sep 2008 19:32:21 +0200 Subject: futex: reduce mmap_sem usage now that we rely on get_user_pages() for the shared key handling move all the mmap_sem stuff closely around the slow paths. Signed-off-by: Peter Zijlstra Acked-by: Nick Piggin Signed-off-by: Ingo Molnar --- kernel/futex.c | 83 +++------------------------------------------------------- 1 file changed, 4 insertions(+), 79 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index a4c39fa..6a72668 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -123,24 +123,6 @@ struct futex_hash_bucket { static struct futex_hash_bucket futex_queues[1<mmap_sem, when futex is shared - */ -static inline void futex_lock_mm(struct rw_semaphore *fshared) -{ - if (fshared) - down_read(fshared); -} - -/* - * Release mm->mmap_sem, when the futex is shared - */ -static inline void futex_unlock_mm(struct rw_semaphore *fshared) -{ - if (fshared) - up_read(fshared); -} - -/* * We hash on the keys returned from get_futex_key (see below). */ static struct futex_hash_bucket *hash_futex(union futex_key *key) @@ -250,7 +232,9 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, } again: + down_read(&mm->mmap_sem); err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL); + up_read(&mm->mmap_sem); if (err < 0) return err; @@ -327,8 +311,7 @@ static int futex_handle_fault(unsigned long address, if (attempt > 2) return ret; - if (!fshared) - down_read(&mm->mmap_sem); + down_read(&mm->mmap_sem); vma = find_vma(mm, address); if (vma && address >= vma->vm_start && (vma->vm_flags & VM_WRITE)) { @@ -348,8 +331,7 @@ static int futex_handle_fault(unsigned long address, current->min_flt++; } } - if (!fshared) - up_read(&mm->mmap_sem); + up_read(&mm->mmap_sem); return ret; } @@ -719,8 +701,6 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, if (!bitset) return -EINVAL; - futex_lock_mm(fshared); - ret = get_futex_key(uaddr, fshared, &key); if (unlikely(ret != 0)) goto out; @@ -749,7 +729,6 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, spin_unlock(&hb->lock); out: put_futex_key(fshared, &key); - futex_unlock_mm(fshared); return ret; } @@ -769,8 +748,6 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared, int ret, op_ret, attempt = 0; retryfull: - futex_lock_mm(fshared); - ret = get_futex_key(uaddr1, fshared, &key1); if (unlikely(ret != 0)) goto out; @@ -821,12 +798,6 @@ retry: goto retry; } - /* - * If we would have faulted, release mmap_sem, - * fault it in and start all over again. - */ - futex_unlock_mm(fshared); - ret = get_user(dummy, uaddr2); if (ret) return ret; @@ -864,7 +835,6 @@ retry: out: put_futex_key(fshared, &key2); put_futex_key(fshared, &key1); - futex_unlock_mm(fshared); return ret; } @@ -884,8 +854,6 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, int ret, drop_count = 0; retry: - futex_lock_mm(fshared); - ret = get_futex_key(uaddr1, fshared, &key1); if (unlikely(ret != 0)) goto out; @@ -908,12 +876,6 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, if (hb1 != hb2) spin_unlock(&hb2->lock); - /* - * If we would have faulted, release mmap_sem, fault - * it in and start all over again. - */ - futex_unlock_mm(fshared); - ret = get_user(curval, uaddr1); if (!ret) @@ -967,7 +929,6 @@ out_unlock: out: put_futex_key(fshared, &key2); put_futex_key(fshared, &key1); - futex_unlock_mm(fshared); return ret; } @@ -1211,8 +1172,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, q.pi_state = NULL; q.bitset = bitset; retry: - futex_lock_mm(fshared); - q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) @@ -1245,12 +1204,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, if (unlikely(ret)) { queue_unlock(&q, hb); - /* - * If we would have faulted, release mmap_sem, fault it in and - * start all over again. - */ - futex_unlock_mm(fshared); - ret = get_user(uval, uaddr); if (!ret) @@ -1265,12 +1218,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, queue_me(&q, hb); /* - * Now the futex is queued and we have checked the data, we - * don't want to hold mmap_sem while we sleep. - */ - futex_unlock_mm(fshared); - - /* * There might have been scheduling since the queue_me(), as we * cannot hold a spinlock across the get_user() in case it * faults, and we cannot just set TASK_INTERRUPTIBLE state when @@ -1355,7 +1302,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, out_release_sem: put_futex_key(fshared, &q.key); - futex_unlock_mm(fshared); return ret; } @@ -1404,8 +1350,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, q.pi_state = NULL; retry: - futex_lock_mm(fshared); - q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, fshared, &q.key); if (unlikely(ret != 0)) @@ -1495,7 +1439,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, * exit to complete. */ queue_unlock(&q, hb); - futex_unlock_mm(fshared); cond_resched(); goto retry; @@ -1527,12 +1470,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, */ queue_me(&q, hb); - /* - * Now the futex is queued and we have checked the data, we - * don't want to hold mmap_sem while we sleep. - */ - futex_unlock_mm(fshared); - WARN_ON(!q.pi_state); /* * Block on the PI mutex: @@ -1545,7 +1482,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, ret = ret ? 0 : -EWOULDBLOCK; } - futex_lock_mm(fshared); spin_lock(q.lock_ptr); if (!ret) { @@ -1611,7 +1547,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, /* Unqueue and drop the lock */ unqueue_me_pi(&q); - futex_unlock_mm(fshared); if (to) destroy_hrtimer_on_stack(&to->timer); @@ -1622,7 +1557,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, out_release_sem: put_futex_key(fshared, &q.key); - futex_unlock_mm(fshared); if (to) destroy_hrtimer_on_stack(&to->timer); return ret; @@ -1646,8 +1580,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, goto retry_unlocked; } - futex_unlock_mm(fshared); - ret = get_user(uval, uaddr); if (!ret && (uval != -EFAULT)) goto retry; @@ -1679,10 +1611,6 @@ retry: */ if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current)) return -EPERM; - /* - * First take all the futex related locks: - */ - futex_lock_mm(fshared); ret = get_futex_key(uaddr, fshared, &key); if (unlikely(ret != 0)) @@ -1742,7 +1670,6 @@ out_unlock: spin_unlock(&hb->lock); out: put_futex_key(fshared, &key); - futex_unlock_mm(fshared); return ret; @@ -1766,8 +1693,6 @@ pi_faulted: goto retry_unlocked; } - futex_unlock_mm(fshared); - ret = get_user(uval, uaddr); if (!ret && (uval != -EFAULT)) goto retry; -- cgit v1.1 From 734b05b10e51d4ba38c8fc3ee02e846aab09eedf Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Sep 2008 19:32:22 +0200 Subject: futex: use fast_gup() Change the get_user_pages() call with fast_gup() which doesn't require holding the mmap_sem thereby removing the mmap_sem from all fast paths. Signed-off-by: Peter Zijlstra Acked-by: Nick Piggin Signed-off-by: Ingo Molnar --- kernel/futex.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 6a72668..facf17d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -232,9 +232,7 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, } again: - down_read(&mm->mmap_sem); - err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL); - up_read(&mm->mmap_sem); + err = get_user_pages_fast(address, 1, 0, &page); if (err < 0) return err; -- cgit v1.1 From c2f9f20154bfb137ccdf8c9159992429a40dfe20 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Sep 2008 19:32:23 +0200 Subject: futex: cleanup fshared fshared doesn't need to be a rw_sem pointer anymore, so clean that up. Signed-off-by: Peter Zijlstra Acked-by: Nick Piggin Signed-off-by: Ingo Molnar --- kernel/futex.c | 48 +++++++++++++++++++----------------------------- 1 file changed, 19 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index facf17d..60b47bb 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -200,8 +200,7 @@ static void drop_futex_key_refs(union futex_key *key) * For other futexes, it points to ¤t->mm->mmap_sem and * caller must have taken the reader lock. but NOT any spinlocks. */ -static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, - union futex_key *key) +static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key) { unsigned long address = (unsigned long)uaddr; struct mm_struct *mm = current->mm; @@ -268,7 +267,7 @@ again: } static inline -void put_futex_key(struct rw_semaphore *fshared, union futex_key *key) +void put_futex_key(int fshared, union futex_key *key) { drop_futex_key_refs(key); } @@ -297,10 +296,8 @@ static int get_futex_value_locked(u32 *dest, u32 __user *from) /* * Fault handling. - * if fshared is non NULL, current->mm->mmap_sem is already held */ -static int futex_handle_fault(unsigned long address, - struct rw_semaphore *fshared, int attempt) +static int futex_handle_fault(unsigned long address, int attempt) { struct vm_area_struct * vma; struct mm_struct *mm = current->mm; @@ -687,8 +684,7 @@ double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2) * Wake up all waiters hashed on the physical page that is mapped * to this virtual address: */ -static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared, - int nr_wake, u32 bitset) +static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset) { struct futex_hash_bucket *hb; struct futex_q *this, *next; @@ -735,8 +731,7 @@ out: * to this virtual address: */ static int -futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared, - u32 __user *uaddr2, +futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, int nr_wake, int nr_wake2, int op) { union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; @@ -790,7 +785,7 @@ retry: */ if (attempt++) { ret = futex_handle_fault((unsigned long)uaddr2, - fshared, attempt); + attempt); if (ret) goto out; goto retry; @@ -841,8 +836,7 @@ out: * Requeue all waiters hashed on one physical page to another * physical page. */ -static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared, - u32 __user *uaddr2, +static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, int nr_wake, int nr_requeue, u32 *cmpval) { union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; @@ -1048,8 +1042,7 @@ static void unqueue_me_pi(struct futex_q *q) * private futexes. */ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, - struct task_struct *newowner, - struct rw_semaphore *fshared) + struct task_struct *newowner, int fshared) { u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; struct futex_pi_state *pi_state = q->pi_state; @@ -1128,7 +1121,7 @@ retry: handle_fault: spin_unlock(q->lock_ptr); - ret = futex_handle_fault((unsigned long)uaddr, fshared, attempt++); + ret = futex_handle_fault((unsigned long)uaddr, attempt++); spin_lock(q->lock_ptr); @@ -1152,7 +1145,7 @@ handle_fault: static long futex_wait_restart(struct restart_block *restart); -static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, +static int futex_wait(u32 __user *uaddr, int fshared, u32 val, ktime_t *abs_time, u32 bitset) { struct task_struct *curr = current; @@ -1307,13 +1300,13 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, static long futex_wait_restart(struct restart_block *restart) { u32 __user *uaddr = (u32 __user *)restart->futex.uaddr; - struct rw_semaphore *fshared = NULL; + int fshared = 0; ktime_t t; t.tv64 = restart->futex.time; restart->fn = do_no_restart_syscall; if (restart->futex.flags & FLAGS_SHARED) - fshared = ¤t->mm->mmap_sem; + fshared = 1; return (long)futex_wait(uaddr, fshared, restart->futex.val, &t, restart->futex.bitset); } @@ -1325,7 +1318,7 @@ static long futex_wait_restart(struct restart_block *restart) * if there are waiters then it will block, it does PI, etc. (Due to * races the kernel might see a 0 value of the futex too.) */ -static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, +static int futex_lock_pi(u32 __user *uaddr, int fshared, int detect, ktime_t *time, int trylock) { struct hrtimer_sleeper timeout, *to = NULL; @@ -1571,8 +1564,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, queue_unlock(&q, hb); if (attempt++) { - ret = futex_handle_fault((unsigned long)uaddr, fshared, - attempt); + ret = futex_handle_fault((unsigned long)uaddr, attempt); if (ret) goto out_release_sem; goto retry_unlocked; @@ -1592,7 +1584,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, * This is the in-kernel slowpath: we look up the PI state (if any), * and do the rt-mutex unlock. */ -static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared) +static int futex_unlock_pi(u32 __user *uaddr, int fshared) { struct futex_hash_bucket *hb; struct futex_q *this, *next; @@ -1683,8 +1675,7 @@ pi_faulted: spin_unlock(&hb->lock); if (attempt++) { - ret = futex_handle_fault((unsigned long)uaddr, fshared, - attempt); + ret = futex_handle_fault((unsigned long)uaddr, attempt); if (ret) goto out; uval = 0; @@ -1816,8 +1807,7 @@ retry: * PI futexes happens in exit_pi_state(): */ if (!pi && (uval & FUTEX_WAITERS)) - futex_wake(uaddr, &curr->mm->mmap_sem, 1, - FUTEX_BITSET_MATCH_ANY); + futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY); } return 0; } @@ -1913,10 +1903,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, { int ret = -ENOSYS; int cmd = op & FUTEX_CMD_MASK; - struct rw_semaphore *fshared = NULL; + int fshared = 0; if (!(op & FUTEX_PRIVATE_FLAG)) - fshared = ¤t->mm->mmap_sem; + fshared = 1; switch (cmd) { case FUTEX_WAIT: -- cgit v1.1 From 42569c39917a08e8de1e8b5685463be7b74baebd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 30 Sep 2008 12:33:07 +0200 Subject: futex: fixup get_futex_key() for private futexes With the get_user_pages_fast() patches we made get_futex_key() obtain a reference on the returned key, but failed to do so for private futexes. Signed-off-by: Peter Zijlstra Acked-by: Nick Piggin Signed-off-by: Ingo Molnar --- kernel/futex.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 60b47bb..62cbd64 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -227,6 +227,7 @@ static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key) return -EFAULT; key->private.mm = mm; key->private.address = address; + get_futex_key_refs(key); return 0; } -- cgit v1.1 From 7317d7b87edb41a9135e30be1ec3f7ef817c53dd Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 30 Sep 2008 20:50:27 +1000 Subject: sched: improve preempt debugging This patch helped me out with a problem I recently had.... Basically, when the kernel lock is held, then preempt_count underflow does not get detected until it is released which may be a long time (and arbitrarily, eg at different points it may be rescheduled). If the bkl is released at schedule, the resulting output is actually fairly cryptic... With any other lock that elevates preempt_count, it is illegal to schedule under it (which would get found pretty quickly). bkl allows scheduling with preempt_count elevated, which makes underflows hard to debug. Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 9889080..ec3bd1f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4305,7 +4305,7 @@ void __kprobes sub_preempt_count(int val) /* * Underflow? */ - if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) + if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked()))) return; /* * Is the spinlock portion underflowing? -- cgit v1.1 From c7e78cff6b7518212247fb20b1dc6411540dc9af Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 16 Oct 2008 23:17:09 +0200 Subject: lockstat: contend with points We currently only provide points that have to wait on contention, also lists the points we have to wait for. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 33 +++++++++++++++++++++------------ kernel/lockdep_proc.c | 21 +++++++++++++++++++-- kernel/mutex.c | 2 +- 3 files changed, 41 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index dbda475..234a9dc 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -136,16 +136,16 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock) #ifdef CONFIG_LOCK_STAT static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); -static int lock_contention_point(struct lock_class *class, unsigned long ip) +static int lock_point(unsigned long points[], unsigned long ip) { int i; - for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) { - if (class->contention_point[i] == 0) { - class->contention_point[i] = ip; + for (i = 0; i < LOCKSTAT_POINTS; i++) { + if (points[i] == 0) { + points[i] = ip; break; } - if (class->contention_point[i] == ip) + if (points[i] == ip) break; } @@ -185,6 +185,9 @@ struct lock_class_stats lock_stats(struct lock_class *class) for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) stats.contention_point[i] += pcs->contention_point[i]; + for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) + stats.contending_point[i] += pcs->contending_point[i]; + lock_time_add(&pcs->read_waittime, &stats.read_waittime); lock_time_add(&pcs->write_waittime, &stats.write_waittime); @@ -209,6 +212,7 @@ void clear_lock_stats(struct lock_class *class) memset(cpu_stats, 0, sizeof(struct lock_class_stats)); } memset(class->contention_point, 0, sizeof(class->contention_point)); + memset(class->contending_point, 0, sizeof(class->contending_point)); } static struct lock_class_stats *get_lock_stats(struct lock_class *class) @@ -3001,7 +3005,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) struct held_lock *hlock, *prev_hlock; struct lock_class_stats *stats; unsigned int depth; - int i, point; + int i, contention_point, contending_point; depth = curr->lockdep_depth; if (DEBUG_LOCKS_WARN_ON(!depth)) @@ -3025,18 +3029,22 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) found_it: hlock->waittime_stamp = sched_clock(); - point = lock_contention_point(hlock_class(hlock), ip); + contention_point = lock_point(hlock_class(hlock)->contention_point, ip); + contending_point = lock_point(hlock_class(hlock)->contending_point, + lock->ip); stats = get_lock_stats(hlock_class(hlock)); - if (point < ARRAY_SIZE(stats->contention_point)) - stats->contention_point[point]++; + if (contention_point < LOCKSTAT_POINTS) + stats->contention_point[contention_point]++; + if (contending_point < LOCKSTAT_POINTS) + stats->contending_point[contending_point]++; if (lock->cpu != smp_processor_id()) stats->bounces[bounce_contended + !!hlock->read]++; put_lock_stats(stats); } static void -__lock_acquired(struct lockdep_map *lock) +__lock_acquired(struct lockdep_map *lock, unsigned long ip) { struct task_struct *curr = current; struct held_lock *hlock, *prev_hlock; @@ -3085,6 +3093,7 @@ found_it: put_lock_stats(stats); lock->cpu = cpu; + lock->ip = ip; } void lock_contended(struct lockdep_map *lock, unsigned long ip) @@ -3106,7 +3115,7 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip) } EXPORT_SYMBOL_GPL(lock_contended); -void lock_acquired(struct lockdep_map *lock) +void lock_acquired(struct lockdep_map *lock, unsigned long ip) { unsigned long flags; @@ -3119,7 +3128,7 @@ void lock_acquired(struct lockdep_map *lock) raw_local_irq_save(flags); check_flags(flags); current->lockdep_recursion = 1; - __lock_acquired(lock); + __lock_acquired(lock, ip); current->lockdep_recursion = 0; raw_local_irq_restore(flags); } diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 8d3a6eba..13716b8 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -557,7 +557,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data) if (stats->read_holdtime.nr) namelen += 2; - for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) { + for (i = 0; i < LOCKSTAT_POINTS; i++) { char sym[KSYM_SYMBOL_LEN]; char ip[32]; @@ -574,6 +574,23 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data) stats->contention_point[i], ip, sym); } + for (i = 0; i < LOCKSTAT_POINTS; i++) { + char sym[KSYM_SYMBOL_LEN]; + char ip[32]; + + if (class->contending_point[i] == 0) + break; + + if (!i) + seq_line(m, '-', 40-namelen, namelen); + + sprint_symbol(sym, class->contending_point[i]); + snprintf(ip, sizeof(ip), "[<%p>]", + (void *)class->contending_point[i]); + seq_printf(m, "%40s %14lu %29s %s\n", name, + stats->contending_point[i], + ip, sym); + } if (i) { seq_puts(m, "\n"); seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1)); @@ -583,7 +600,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data) static void seq_header(struct seq_file *m) { - seq_printf(m, "lock_stat version 0.2\n"); + seq_printf(m, "lock_stat version 0.3\n"); seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1)); seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s " "%14s %14s\n", diff --git a/kernel/mutex.c b/kernel/mutex.c index 12c779d..39a3816 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -184,7 +184,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, } done: - lock_acquired(&lock->dep_map); + lock_acquired(&lock->dep_map, ip); /* got the lock - rejoice! */ mutex_remove_waiter(lock, &waiter, task_thread_info(task)); debug_mutex_set_owner(lock, task_thread_info(task)); -- cgit v1.1 From 0eec481e8fb000a209fda9bf8f466aca87dc1150 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 15 Oct 2008 14:56:37 +0800 Subject: markers: simplify marker_set_format() current marker_set_format() is complex this patch simplify it, and decrease the overhead of marker_update_probes(). Signed-off-by: Lai Jiangshan Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 71 ++++++++++++++++++++------------------------------------- 1 file changed, 25 insertions(+), 46 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index e9c6b2b..75a1a17 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -64,6 +64,7 @@ struct marker_entry { void *oldptr; int rcu_pending; unsigned char ptype:1; + unsigned char format_allocated:1; char name[0]; /* Contains name'\0'format'\0' */ }; @@ -416,6 +417,7 @@ static struct marker_entry *add_marker(const char *name, const char *format) e->single.probe_private = NULL; e->multi = NULL; e->ptype = 0; + e->format_allocated = 0; e->refcount = 0; e->rcu_pending = 0; hlist_add_head(&e->hlist, head); @@ -447,6 +449,8 @@ static int remove_marker(const char *name) if (e->single.func != __mark_empty_function) return -EBUSY; hlist_del(&e->hlist); + if (e->format_allocated) + kfree(e->format); /* Make sure the call_rcu has been executed */ if (e->rcu_pending) rcu_barrier_sched(); @@ -457,57 +461,34 @@ static int remove_marker(const char *name) /* * Set the mark_entry format to the format found in the element. */ -static int marker_set_format(struct marker_entry **entry, const char *format) +static int marker_set_format(struct marker_entry *entry, const char *format) { - struct marker_entry *e; - size_t name_len = strlen((*entry)->name) + 1; - size_t format_len = strlen(format) + 1; - - - e = kmalloc(sizeof(struct marker_entry) + name_len + format_len, - GFP_KERNEL); - if (!e) + entry->format = kstrdup(format, GFP_KERNEL); + if (!entry->format) return -ENOMEM; - memcpy(&e->name[0], (*entry)->name, name_len); - e->format = &e->name[name_len]; - memcpy(e->format, format, format_len); - if (strcmp(e->format, MARK_NOARGS) == 0) - e->call = marker_probe_cb_noarg; - else - e->call = marker_probe_cb; - e->single = (*entry)->single; - e->multi = (*entry)->multi; - e->ptype = (*entry)->ptype; - e->refcount = (*entry)->refcount; - e->rcu_pending = 0; - hlist_add_before(&e->hlist, &(*entry)->hlist); - hlist_del(&(*entry)->hlist); - /* Make sure the call_rcu has been executed */ - if ((*entry)->rcu_pending) - rcu_barrier_sched(); - kfree(*entry); - *entry = e; + entry->format_allocated = 1; + trace_mark(core_marker_format, "name %s format %s", - e->name, e->format); + entry->name, entry->format); return 0; } /* * Sets the probe callback corresponding to one marker. */ -static int set_marker(struct marker_entry **entry, struct marker *elem, +static int set_marker(struct marker_entry *entry, struct marker *elem, int active) { int ret; - WARN_ON(strcmp((*entry)->name, elem->name) != 0); + WARN_ON(strcmp(entry->name, elem->name) != 0); - if ((*entry)->format) { - if (strcmp((*entry)->format, elem->format) != 0) { + if (entry->format) { + if (strcmp(entry->format, elem->format) != 0) { printk(KERN_NOTICE "Format mismatch for probe %s " "(%s), marker (%s)\n", - (*entry)->name, - (*entry)->format, + entry->name, + entry->format, elem->format); return -EPERM; } @@ -523,34 +504,33 @@ static int set_marker(struct marker_entry **entry, struct marker *elem, * pass from a "safe" callback (with argument) to an "unsafe" * callback (does not set arguments). */ - elem->call = (*entry)->call; + elem->call = entry->call; /* * Sanity check : * We only update the single probe private data when the ptr is * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1) */ WARN_ON(elem->single.func != __mark_empty_function - && elem->single.probe_private - != (*entry)->single.probe_private && - !elem->ptype); - elem->single.probe_private = (*entry)->single.probe_private; + && elem->single.probe_private != entry->single.probe_private + && !elem->ptype); + elem->single.probe_private = entry->single.probe_private; /* * Make sure the private data is valid when we update the * single probe ptr. */ smp_wmb(); - elem->single.func = (*entry)->single.func; + elem->single.func = entry->single.func; /* * We also make sure that the new probe callbacks array is consistent * before setting a pointer to it. */ - rcu_assign_pointer(elem->multi, (*entry)->multi); + rcu_assign_pointer(elem->multi, entry->multi); /* * Update the function or multi probe array pointer before setting the * ptype. */ smp_wmb(); - elem->ptype = (*entry)->ptype; + elem->ptype = entry->ptype; elem->state = active; return 0; @@ -594,8 +574,7 @@ void marker_update_probe_range(struct marker *begin, for (iter = begin; iter < end; iter++) { mark_entry = get_marker(iter->name); if (mark_entry) { - set_marker(&mark_entry, iter, - !!mark_entry->refcount); + set_marker(mark_entry, iter, !!mark_entry->refcount); /* * ignore error, continue */ @@ -657,7 +636,7 @@ int marker_probe_register(const char *name, const char *format, ret = PTR_ERR(entry); } else if (format) { if (!entry->format) - ret = marker_set_format(&entry, format); + ret = marker_set_format(entry, format); else if (strcmp(entry->format, format)) ret = -EPERM; } -- cgit v1.1 From 505e371da195fad20cb8aaf45407a2849774d6d0 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 15 Oct 2008 14:56:42 +0800 Subject: markers: remove exported symbol marker_probe_cb_noarg() marker_probe_cb_noarg() should not be seen by outer code. this patch remove it. Signed-off-by: Lai Jiangshan Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 75a1a17..2319264 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -158,7 +158,7 @@ EXPORT_SYMBOL_GPL(marker_probe_cb); * * Should be connected to markers "MARK_NOARGS". */ -void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...) +static void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...) { va_list args; /* not initialized */ char ptype; @@ -198,7 +198,6 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...) } rcu_read_unlock_sched(); } -EXPORT_SYMBOL_GPL(marker_probe_cb_noarg); static void free_old_closure(struct rcu_head *head) { -- cgit v1.1 From 4de62748e69c31fc4fd5bc43b73e9cf60a17ec53 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 15 Oct 2008 14:56:47 +0800 Subject: markers: let marker_table be close to its comments marker_table is defined far from its comments, this fix make cleanup for it. Signed-off-by: Lai Jiangshan Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 2319264..0f2a944 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -43,6 +43,7 @@ static DEFINE_MUTEX(markers_mutex); */ #define MARKER_HASH_BITS 6 #define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS) +static struct hlist_head marker_table[MARKER_TABLE_SIZE]; /* * Note about RCU : @@ -68,8 +69,6 @@ struct marker_entry { char name[0]; /* Contains name'\0'format'\0' */ }; -static struct hlist_head marker_table[MARKER_TABLE_SIZE]; - /** * __mark_empty_function - Empty probe callback * @probe_private: probe private data -- cgit v1.1 From 5d9881ea1440f046ee851bbaa2a2962543336a11 Mon Sep 17 00:00:00 2001 From: Zhaolei Date: Wed, 22 Oct 2008 11:38:01 +0800 Subject: markers: break the redundant loop in kernel/marker.c Impact: cleanup, no functionality changed Because e->name is unique in list, we don't need to continue the iteration after matched. Signed-off-by: Zhao Lei Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 0f2a944..2898b64 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -825,8 +825,6 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe, if (!e->ptype) { if (num == 0 && e->single.func == probe) return e->single.probe_private; - else - break; } else { struct marker_probe_closure *closure; int match = 0; @@ -838,6 +836,7 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe, return closure[i].probe_private; } } + break; } } return ERR_PTR(-ENOENT); -- cgit v1.1 From 944ac4259e39801c843a915c3da8194ac9af0440 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 23 Oct 2008 19:26:08 -0400 Subject: ftrace: ftrace dump on oops control Impact: add (default-off) dump-trace-on-oops flag Currently, ftrace is set up to dump its contents to the console if the kernel panics or oops. This can be annoying if you have trace data in the buffers and you experience an oops, but the trace data is old or static. Usually when you want ftrace to dump its contents is when you are debugging your system and you have set up ftrace to trace the events leading to an oops. This patch adds a control variable called "ftrace_dump_on_oops" that will enable the ftrace dump to console on oops. This variable is default off but a developer can enable it either through the kernel command line by adding "ftrace_dump_on_oops" or at run time by setting (or disabling) /proc/sys/kernel/ftrace_dump_on_oops. v2: Replaced /** with /* as Randy explained that kernel-doc does not yet handle variables. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/sysctl.c | 10 ++++++++++ kernel/trace/trace.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a13bd4d..84754f5 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -484,6 +484,16 @@ static struct ctl_table kern_table[] = { .proc_handler = &ftrace_enable_sysctl, }, #endif +#ifdef CONFIG_TRACING + { + .ctl_name = CTL_UNNUMBERED, + .procname = "ftrace_dump_on_opps", + .data = &ftrace_dump_on_oops, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, +#endif #ifdef CONFIG_MODULES { .ctl_name = KERN_MODPROBE, diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d345d64..47f46cb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -63,6 +63,28 @@ static cpumask_t __read_mostly tracing_buffer_mask; static int tracing_disabled = 1; +/* + * ftrace_dump_on_oops - variable to dump ftrace buffer on oops + * + * If there is an oops (or kernel panic) and the ftrace_dump_on_oops + * is set, then ftrace_dump is called. This will output the contents + * of the ftrace buffers to the console. This is very useful for + * capturing traces that lead to crashes and outputing it to a + * serial console. + * + * It is default off, but you can enable it with either specifying + * "ftrace_dump_on_oops" in the kernel command line, or setting + * /proc/sys/kernel/ftrace_dump_on_oops to true. + */ +int ftrace_dump_on_oops; + +static int __init set_ftrace_dump_on_oops(char *str) +{ + ftrace_dump_on_oops = 1; + return 1; +} +__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); + long ns2usecs(cycle_t nsec) { @@ -3021,7 +3043,8 @@ EXPORT_SYMBOL_GPL(__ftrace_printk); static int trace_panic_handler(struct notifier_block *this, unsigned long event, void *unused) { - ftrace_dump(); + if (ftrace_dump_on_oops) + ftrace_dump(); return NOTIFY_OK; } @@ -3037,7 +3060,8 @@ static int trace_die_handler(struct notifier_block *self, { switch (val) { case DIE_OOPS: - ftrace_dump(); + if (ftrace_dump_on_oops) + ftrace_dump(); break; default: break; @@ -3078,7 +3102,6 @@ trace_printk_seq(struct trace_seq *s) trace_seq_reset(s); } - void ftrace_dump(void) { static DEFINE_SPINLOCK(ftrace_dump_lock); -- cgit v1.1 From b807c3d0f8e39ed7cbbbe6da162650e305e8de15 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 30 Oct 2008 16:08:33 -0400 Subject: ftrace: nmi update statistics Impact: add more debug info to /debugfs/tracing/dyn_ftrace_total_info This patch adds dynamic ftrace NMI update statistics to the /debugfs/tracing/dyn_ftrace_total_info stat file. Signed-off-by: Steven Rostedt Cc: Peter Zijlstra Cc: Andrew Morton Cc: Linus Torvalds Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a610ca7..bc36feb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2815,22 +2815,39 @@ static struct file_operations tracing_mark_fops = { #ifdef CONFIG_DYNAMIC_FTRACE +#define DYN_INFO_BUF_SIZE 1023 +static char ftrace_dyn_info_buffer[DYN_INFO_BUF_SIZE+1]; +static DEFINE_MUTEX(dyn_info_mutex); + +int __weak ftrace_arch_read_dyn_info(char *buf, int size) +{ + return 0; +} + static ssize_t -tracing_read_long(struct file *filp, char __user *ubuf, +tracing_read_dyn_info(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long *p = filp->private_data; - char buf[64]; + char *buf = ftrace_dyn_info_buffer; int r; - r = sprintf(buf, "%ld\n", *p); + mutex_lock(&dyn_info_mutex); + r = sprintf(buf, "%ld ", *p); - return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); + r += ftrace_arch_read_dyn_info(buf+r, DYN_INFO_BUF_SIZE-r); + buf[r++] = '\n'; + + r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); + + mutex_unlock(&dyn_info_mutex); + + return r; } -static struct file_operations tracing_read_long_fops = { +static struct file_operations tracing_dyn_info_fops = { .open = tracing_open_generic, - .read = tracing_read_long, + .read = tracing_read_dyn_info, }; #endif @@ -2939,7 +2956,7 @@ static __init int tracer_init_debugfs(void) #ifdef CONFIG_DYNAMIC_FTRACE entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer, &ftrace_update_tot_cnt, - &tracing_read_long_fops); + &tracing_dyn_info_fops); if (!entry) pr_warning("Could not create debugfs " "'dyn_ftrace_total_info' entry\n"); -- cgit v1.1 From a26a2a27396c0a0877aa701f8f92d08ba550a6c9 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 31 Oct 2008 00:03:22 -0400 Subject: ftrace: nmi safe code clean ups Impact: cleanup This patch cleans up the NMI safe code for dynamic ftrace as suggested by Andrew Morton. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bc36feb..7f86067 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2815,10 +2815,6 @@ static struct file_operations tracing_mark_fops = { #ifdef CONFIG_DYNAMIC_FTRACE -#define DYN_INFO_BUF_SIZE 1023 -static char ftrace_dyn_info_buffer[DYN_INFO_BUF_SIZE+1]; -static DEFINE_MUTEX(dyn_info_mutex); - int __weak ftrace_arch_read_dyn_info(char *buf, int size) { return 0; @@ -2828,14 +2824,17 @@ static ssize_t tracing_read_dyn_info(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { + static char ftrace_dyn_info_buffer[1024]; + static DEFINE_MUTEX(dyn_info_mutex); unsigned long *p = filp->private_data; char *buf = ftrace_dyn_info_buffer; + int size = ARRAY_SIZE(ftrace_dyn_info_buffer); int r; mutex_lock(&dyn_info_mutex); r = sprintf(buf, "%ld ", *p); - r += ftrace_arch_read_dyn_info(buf+r, DYN_INFO_BUF_SIZE-r); + r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r); buf[r++] = '\n'; r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); -- cgit v1.1 From d9e540762f5cdd89f24e518ad1fd31142d0b9726 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 1 Nov 2008 19:57:37 +0100 Subject: ftrace: ftrace_dump_on_oops=[tracer] Impact: add new (optional) debug boot option In order to facilitate early boot trouble, allow one to specify a tracer on the kernel boot line. Signed-off-by: Peter Zijlstra Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 58 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bdb1df0..482583e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -79,6 +79,15 @@ static int tracing_disabled = 1; */ int ftrace_dump_on_oops; +static int tracing_set_tracer(char *buf); + +static int __init set_ftrace(char *str) +{ + tracing_set_tracer(str); + return 1; +} +__setup("ftrace", set_ftrace); + static int __init set_ftrace_dump_on_oops(char *str) { ftrace_dump_on_oops = 1; @@ -2394,29 +2403,11 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf, return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } -static ssize_t -tracing_set_trace_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) +static int tracing_set_tracer(char *buf) { struct trace_array *tr = &global_trace; struct tracer *t; - char buf[max_tracer_type_len+1]; - int i; - size_t ret; - - ret = cnt; - - if (cnt > max_tracer_type_len) - cnt = max_tracer_type_len; - - if (copy_from_user(&buf, ubuf, cnt)) - return -EFAULT; - - buf[cnt] = 0; - - /* strip ending whitespace. */ - for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) - buf[i] = 0; + int ret = 0; mutex_lock(&trace_types_lock); for (t = trace_types; t; t = t->next) { @@ -2440,6 +2431,33 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, out: mutex_unlock(&trace_types_lock); + return ret; +} + +static ssize_t +tracing_set_trace_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[max_tracer_type_len+1]; + int i; + size_t ret; + + if (cnt > max_tracer_type_len) + cnt = max_tracer_type_len; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + /* strip ending whitespace. */ + for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) + buf[i] = 0; + + ret = tracing_set_tracer(buf); + if (!ret) + ret = cnt; + if (ret > 0) filp->f_pos += ret; -- cgit v1.1 From 19dba33c43a2f0f2aa727ae075ec3b11330775ef Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 28 Oct 2008 10:51:49 +0800 Subject: tracepoint: simplification for tracepoints using RCU Impact: simplify implementation Now, unused memory is handled by struct tp_probes. old code use these three field to handle unused memory. struct tracepoint_entry { ... struct rcu_head rcu; void *oldptr; unsigned char rcu_pending:1; ... }; in this way, unused memory is handled by struct tracepoint_entry. it bring reenter bug(it was fixed) and tracepoint.c is filled full of ".*rcu.*" code statements. this patch removes all these. and: rcu_barrier_sched() is removed. Do not need regain tracepoints_mutex after tracepoint_update_probes() several little cleanup. Signed-off-by: Lai Jiangshan Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/tracepoint.c | 111 ++++++++++++++++++---------------------------------- 1 file changed, 37 insertions(+), 74 deletions(-) (limited to 'kernel') diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index af8c856..3e22867 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -43,6 +43,7 @@ static DEFINE_MUTEX(tracepoints_mutex); */ #define TRACEPOINT_HASH_BITS 6 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) +static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; /* * Note about RCU : @@ -54,40 +55,40 @@ struct tracepoint_entry { struct hlist_node hlist; void **funcs; int refcount; /* Number of times armed. 0 if disarmed. */ - struct rcu_head rcu; - void *oldptr; - unsigned char rcu_pending:1; char name[0]; }; -static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; +struct tp_probes { + struct rcu_head rcu; + void *probes[0]; +}; -static void free_old_closure(struct rcu_head *head) +static inline void *allocate_probes(int count) { - struct tracepoint_entry *entry = container_of(head, - struct tracepoint_entry, rcu); - kfree(entry->oldptr); - /* Make sure we free the data before setting the pending flag to 0 */ - smp_wmb(); - entry->rcu_pending = 0; + struct tp_probes *p = kmalloc(count * sizeof(void *) + + sizeof(struct tp_probes), GFP_KERNEL); + return p == NULL ? NULL : p->probes; } -static void tracepoint_entry_free_old(struct tracepoint_entry *entry, void *old) +static void rcu_free_old_probes(struct rcu_head *head) { - if (!old) - return; - entry->oldptr = old; - entry->rcu_pending = 1; - /* write rcu_pending before calling the RCU callback */ - smp_wmb(); - call_rcu_sched(&entry->rcu, free_old_closure); + kfree(container_of(head, struct tp_probes, rcu)); +} + +static inline void release_probes(void *old) +{ + if (old) { + struct tp_probes *tp_probes = container_of(old, + struct tp_probes, probes[0]); + call_rcu(&tp_probes->rcu, rcu_free_old_probes); + } } static void debug_print_probes(struct tracepoint_entry *entry) { int i; - if (!tracepoint_debug) + if (!tracepoint_debug || !entry->funcs) return; for (i = 0; entry->funcs[i]; i++) @@ -111,12 +112,13 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe) return ERR_PTR(-EEXIST); } /* + 2 : one for new probe, one for NULL func */ - new = kzalloc((nr_probes + 2) * sizeof(void *), GFP_KERNEL); + new = allocate_probes(nr_probes + 2); if (new == NULL) return ERR_PTR(-ENOMEM); if (old) memcpy(new, old, nr_probes * sizeof(void *)); new[nr_probes] = probe; + new[nr_probes + 1] = NULL; entry->refcount = nr_probes + 1; entry->funcs = new; debug_print_probes(entry); @@ -132,7 +134,7 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe) old = entry->funcs; if (!old) - return NULL; + return ERR_PTR(-ENOENT); debug_print_probes(entry); /* (N -> M), (N > 1, M >= 0) probes */ @@ -151,13 +153,13 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe) int j = 0; /* N -> M, (N > 1, M > 0) */ /* + 1 for NULL */ - new = kzalloc((nr_probes - nr_del + 1) - * sizeof(void *), GFP_KERNEL); + new = allocate_probes(nr_probes - nr_del + 1); if (new == NULL) return ERR_PTR(-ENOMEM); for (i = 0; old[i]; i++) if ((probe && old[i] != probe)) new[j++] = old[i]; + new[nr_probes - nr_del] = NULL; entry->refcount = nr_probes - nr_del; entry->funcs = new; } @@ -215,7 +217,6 @@ static struct tracepoint_entry *add_tracepoint(const char *name) memcpy(&e->name[0], name, name_len); e->funcs = NULL; e->refcount = 0; - e->rcu_pending = 0; hlist_add_head(&e->hlist, head); return e; } @@ -224,32 +225,10 @@ static struct tracepoint_entry *add_tracepoint(const char *name) * Remove the tracepoint from the tracepoint hash table. Must be called with * mutex_lock held. */ -static int remove_tracepoint(const char *name) +static inline void remove_tracepoint(struct tracepoint_entry *e) { - struct hlist_head *head; - struct hlist_node *node; - struct tracepoint_entry *e; - int found = 0; - size_t len = strlen(name) + 1; - u32 hash = jhash(name, len-1, 0); - - head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; - hlist_for_each_entry(e, node, head, hlist) { - if (!strcmp(name, e->name)) { - found = 1; - break; - } - } - if (!found) - return -ENOENT; - if (e->refcount) - return -EBUSY; hlist_del(&e->hlist); - /* Make sure the call_rcu_sched has been executed */ - if (e->rcu_pending) - rcu_barrier_sched(); kfree(e); - return 0; } /* @@ -343,25 +322,17 @@ int tracepoint_probe_register(const char *name, void *probe) goto end; } } - /* - * If we detect that a call_rcu_sched is pending for this tracepoint, - * make sure it's executed now. - */ - if (entry->rcu_pending) - rcu_barrier_sched(); old = tracepoint_entry_add_probe(entry, probe); if (IS_ERR(old)) { + if (!entry->refcount) + remove_tracepoint(entry); ret = PTR_ERR(old); goto end; } mutex_unlock(&tracepoints_mutex); tracepoint_update_probes(); /* may update entry */ - mutex_lock(&tracepoints_mutex); - entry = get_tracepoint(name); - WARN_ON(!entry); - if (entry->rcu_pending) - rcu_barrier_sched(); - tracepoint_entry_free_old(entry, old); + release_probes(old); + return 0; end: mutex_unlock(&tracepoints_mutex); return ret; @@ -388,25 +359,17 @@ int tracepoint_probe_unregister(const char *name, void *probe) entry = get_tracepoint(name); if (!entry) goto end; - if (entry->rcu_pending) - rcu_barrier_sched(); old = tracepoint_entry_remove_probe(entry, probe); - if (!old) { - printk(KERN_WARNING "Warning: Trying to unregister a probe" - "that doesn't exist\n"); + if (IS_ERR(old)) { + ret = PTR_ERR(old); goto end; } + if (!entry->refcount) + remove_tracepoint(entry); mutex_unlock(&tracepoints_mutex); tracepoint_update_probes(); /* may update entry */ - mutex_lock(&tracepoints_mutex); - entry = get_tracepoint(name); - if (!entry) - goto end; - if (entry->rcu_pending) - rcu_barrier_sched(); - tracepoint_entry_free_old(entry, old); - remove_tracepoint(name); /* Ignore busy error message */ - ret = 0; + release_probes(old); + return 0; end: mutex_unlock(&tracepoints_mutex); return ret; -- cgit v1.1 From 127cafbb276266b1b8da967bfe25a062ab1d42ab Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 28 Oct 2008 10:51:53 +0800 Subject: tracepoint: introduce *_noupdate APIs. Impact: add new tracepoint APIs to allow the batched registration of probes new APIs separate tracepoint_probe_register(), tracepoint_probe_unregister() into 2 steps. The first step of them is just update tracepoint_entry, not connect or disconnect. this patch introduces tracepoint_probe_update_all() for update all. these APIs are very useful for registering lots of probes but just updating once. Another very important thing is that *_noupdate APIs do not require module_mutex. Signed-off-by: Lai Jiangshan Acked-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/tracepoint.c | 170 ++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 132 insertions(+), 38 deletions(-) (limited to 'kernel') diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 3e22867..e96590f 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -59,7 +59,10 @@ struct tracepoint_entry { }; struct tp_probes { - struct rcu_head rcu; + union { + struct rcu_head rcu; + struct list_head list; + } u; void *probes[0]; }; @@ -72,7 +75,7 @@ static inline void *allocate_probes(int count) static void rcu_free_old_probes(struct rcu_head *head) { - kfree(container_of(head, struct tp_probes, rcu)); + kfree(container_of(head, struct tp_probes, u.rcu)); } static inline void release_probes(void *old) @@ -80,7 +83,7 @@ static inline void release_probes(void *old) if (old) { struct tp_probes *tp_probes = container_of(old, struct tp_probes, probes[0]); - call_rcu(&tp_probes->rcu, rcu_free_old_probes); + call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); } } @@ -299,6 +302,23 @@ static void tracepoint_update_probes(void) module_update_tracepoints(); } +static void *tracepoint_add_probe(const char *name, void *probe) +{ + struct tracepoint_entry *entry; + void *old; + + entry = get_tracepoint(name); + if (!entry) { + entry = add_tracepoint(name); + if (IS_ERR(entry)) + return entry; + } + old = tracepoint_entry_add_probe(entry, probe); + if (IS_ERR(old) && !entry->refcount) + remove_tracepoint(entry); + return old; +} + /** * tracepoint_probe_register - Connect a probe to a tracepoint * @name: tracepoint name @@ -309,36 +329,36 @@ static void tracepoint_update_probes(void) */ int tracepoint_probe_register(const char *name, void *probe) { - struct tracepoint_entry *entry; - int ret = 0; void *old; mutex_lock(&tracepoints_mutex); - entry = get_tracepoint(name); - if (!entry) { - entry = add_tracepoint(name); - if (IS_ERR(entry)) { - ret = PTR_ERR(entry); - goto end; - } - } - old = tracepoint_entry_add_probe(entry, probe); - if (IS_ERR(old)) { - if (!entry->refcount) - remove_tracepoint(entry); - ret = PTR_ERR(old); - goto end; - } + old = tracepoint_add_probe(name, probe); mutex_unlock(&tracepoints_mutex); + if (IS_ERR(old)) + return PTR_ERR(old); + tracepoint_update_probes(); /* may update entry */ release_probes(old); return 0; -end: - mutex_unlock(&tracepoints_mutex); - return ret; } EXPORT_SYMBOL_GPL(tracepoint_probe_register); +static void *tracepoint_remove_probe(const char *name, void *probe) +{ + struct tracepoint_entry *entry; + void *old; + + entry = get_tracepoint(name); + if (!entry) + return ERR_PTR(-ENOENT); + old = tracepoint_entry_remove_probe(entry, probe); + if (IS_ERR(old)) + return old; + if (!entry->refcount) + remove_tracepoint(entry); + return old; +} + /** * tracepoint_probe_unregister - Disconnect a probe from a tracepoint * @name: tracepoint name @@ -351,31 +371,105 @@ EXPORT_SYMBOL_GPL(tracepoint_probe_register); */ int tracepoint_probe_unregister(const char *name, void *probe) { - struct tracepoint_entry *entry; void *old; - int ret = -ENOENT; mutex_lock(&tracepoints_mutex); - entry = get_tracepoint(name); - if (!entry) - goto end; - old = tracepoint_entry_remove_probe(entry, probe); - if (IS_ERR(old)) { - ret = PTR_ERR(old); - goto end; - } - if (!entry->refcount) - remove_tracepoint(entry); + old = tracepoint_remove_probe(name, probe); mutex_unlock(&tracepoints_mutex); + if (IS_ERR(old)) + return PTR_ERR(old); + tracepoint_update_probes(); /* may update entry */ release_probes(old); return 0; -end: - mutex_unlock(&tracepoints_mutex); - return ret; } EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); +static LIST_HEAD(old_probes); +static int need_update; + +static void tracepoint_add_old_probes(void *old) +{ + need_update = 1; + if (old) { + struct tp_probes *tp_probes = container_of(old, + struct tp_probes, probes[0]); + list_add(&tp_probes->u.list, &old_probes); + } +} + +/** + * tracepoint_probe_register_noupdate - register a probe but not connect + * @name: tracepoint name + * @probe: probe handler + * + * caller must call tracepoint_probe_update_all() + */ +int tracepoint_probe_register_noupdate(const char *name, void *probe) +{ + void *old; + + mutex_lock(&tracepoints_mutex); + old = tracepoint_add_probe(name, probe); + if (IS_ERR(old)) { + mutex_unlock(&tracepoints_mutex); + return PTR_ERR(old); + } + tracepoint_add_old_probes(old); + mutex_unlock(&tracepoints_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); + +/** + * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect + * @name: tracepoint name + * @probe: probe function pointer + * + * caller must call tracepoint_probe_update_all() + */ +int tracepoint_probe_unregister_noupdate(const char *name, void *probe) +{ + void *old; + + mutex_lock(&tracepoints_mutex); + old = tracepoint_remove_probe(name, probe); + if (IS_ERR(old)) { + mutex_unlock(&tracepoints_mutex); + return PTR_ERR(old); + } + tracepoint_add_old_probes(old); + mutex_unlock(&tracepoints_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); + +/** + * tracepoint_probe_update_all - update tracepoints + */ +void tracepoint_probe_update_all(void) +{ + LIST_HEAD(release_probes); + struct tp_probes *pos, *next; + + mutex_lock(&tracepoints_mutex); + if (!need_update) { + mutex_unlock(&tracepoints_mutex); + return; + } + if (!list_empty(&old_probes)) + list_replace_init(&old_probes, &release_probes); + need_update = 0; + mutex_unlock(&tracepoints_mutex); + + tracepoint_update_probes(); + list_for_each_entry_safe(pos, next, &release_probes, u.list) { + list_del(&pos->u.list); + call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); + } +} +EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); + /** * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. * @tracepoint: current tracepoints (in), next tracepoint (out) -- cgit v1.1 From be19ef82e068e92a28df50341938fdeb5ea56436 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 3 Nov 2008 14:35:12 +0100 Subject: rcu: make rcu-stall debug printout more standard Impact: change debug printout Change "RCU detected CPU stall" to "INFO: RCU detected CPU stall" message, to make it easier for tools to pick up the warning. Signed-off-by: Ingo Molnar --- kernel/rcuclassic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c index 37f72e551..e503a00 100644 --- a/kernel/rcuclassic.c +++ b/kernel/rcuclassic.c @@ -191,7 +191,7 @@ static void print_other_cpu_stall(struct rcu_ctrlblk *rcp) /* OK, time to rat on our buddy... */ - printk(KERN_ERR "RCU detected CPU stalls:"); + printk(KERN_ERR "INFO: RCU detected CPU stalls:"); for_each_possible_cpu(cpu) { if (cpu_isset(cpu, rcp->cpumask)) printk(" %d", cpu); @@ -204,7 +204,7 @@ static void print_cpu_stall(struct rcu_ctrlblk *rcp) { unsigned long flags; - printk(KERN_ERR "RCU detected CPU %d stall (t=%lu/%lu jiffies)\n", + printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu/%lu jiffies)\n", smp_processor_id(), jiffies, jiffies - rcp->gp_start); dump_stack(); -- cgit v1.1 From 8f0a056fcb2f83a069fb5d60c2383304b7456687 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 3 Nov 2008 23:15:55 -0500 Subject: ftrace: introduce ftrace_preempt_disable()/enable() Impact: add new ftrace-plugin internal APIs Parts of the tracer needs to be careful about schedule recursion. If the NEED_RESCHED flag is set, a preempt_enable will call schedule. Inside the schedule function, the NEED_RESCHED flag is cleared. The problem arises when a trace happens in the schedule function but before NEED_RESCHED is cleared. The race is as follows: schedule() >> tracer called trace_function() preempt_disable() [ record trace ] preempt_enable() <<- here's the issue. [check NEED_RESCHED] schedule() [ Repeat the above, over and over again ] The naive approach is simply to use preempt_enable_no_schedule instead. The problem with that approach is that, although we solve the schedule recursion issue, we now might lose a preemption check when not in the schedule function. trace_function() preempt_disable() [ record trace ] [Interrupt comes in and sets NEED_RESCHED] preempt_enable_no_resched() [continue without scheduling] The way ftrace handles this problem is with the following approach: int resched; resched = need_resched(); preempt_disable_notrace(); [record trace] if (resched) preempt_enable_no_sched_notrace(); else preempt_enable_notrace(); This may seem like the opposite of what we want. If resched is set then we call the "no_sched" version?? The reason we do this is because if NEED_RESCHED is set before we disable preemption, there's two reasons for that: 1) we are in an atomic code path 2) we are already on our way to the schedule function, and maybe even in the schedule function, but have yet to clear the flag. Both the above cases we do not want to schedule. This solution has already been implemented within the ftrace infrastructure. But the problem is that it has been implemented several times. This patch encapsulates this code to two nice functions. resched = ftrace_preempt_disable(); [ record trace] ftrace_preempt_enable(resched); This way the tracers do not need to worry about getting it right. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8465ad0..10c6dae 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -419,4 +419,52 @@ enum trace_iterator_flags { extern struct tracer nop_trace; +/** + * ftrace_preempt_disable - disable preemption scheduler safe + * + * When tracing can happen inside the scheduler, there exists + * cases that the tracing might happen before the need_resched + * flag is checked. If this happens and the tracer calls + * preempt_enable (after a disable), a schedule might take place + * causing an infinite recursion. + * + * To prevent this, we read the need_recshed flag before + * disabling preemption. When we want to enable preemption we + * check the flag, if it is set, then we call preempt_enable_no_resched. + * Otherwise, we call preempt_enable. + * + * The rational for doing the above is that if need resched is set + * and we have yet to reschedule, we are either in an atomic location + * (where we do not need to check for scheduling) or we are inside + * the scheduler and do not want to resched. + */ +static inline int ftrace_preempt_disable(void) +{ + int resched; + + resched = need_resched(); + preempt_disable_notrace(); + + return resched; +} + +/** + * ftrace_preempt_enable - enable preemption scheduler safe + * @resched: the return value from ftrace_preempt_disable + * + * This is a scheduler safe way to enable preemption and not miss + * any preemption checks. The disabled saved the state of preemption. + * If resched is set, then we were either inside an atomic or + * are inside the scheduler (we would have already scheduled + * otherwise). In this case, we do not want to call normal + * preempt_enable, but preempt_enable_no_resched instead. + */ +static inline void ftrace_preempt_enable(int resched) +{ + if (resched) + preempt_enable_no_resched_notrace(); + else + preempt_enable_notrace(); +} + #endif /* _LINUX_KERNEL_TRACE_H */ -- cgit v1.1 From 182e9f5f704ed6b9175142fe8da33c9ce0c52b52 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 3 Nov 2008 23:15:56 -0500 Subject: ftrace: insert in the ftrace_preempt_disable()/enable() functions Impact: use new, consolidated APIs in ftrace plugins This patch replaces the schedule safe preempt disable code with the ftrace_preempt_disable() and ftrace_preempt_enable() safe functions. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 27 +++++++++------------------ kernel/trace/trace.c | 8 ++------ kernel/trace/trace_sched_wakeup.c | 13 ++----------- kernel/trace/trace_stack.c | 8 ++------ 4 files changed, 15 insertions(+), 41 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index cedf4e2..151f6a7 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -16,6 +16,8 @@ #include #include +#include "trace.h" + /* Up this if you want to test the TIME_EXTENTS and normalization */ #define DEBUG_SHIFT 0 @@ -1122,8 +1124,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, return NULL; /* If we are tracing schedule, we don't want to recurse */ - resched = need_resched(); - preempt_disable_notrace(); + resched = ftrace_preempt_disable(); cpu = raw_smp_processor_id(); @@ -1154,10 +1155,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, return event; out: - if (resched) - preempt_enable_notrace(); - else - preempt_enable_notrace(); + ftrace_preempt_enable(resched); return NULL; } @@ -1199,12 +1197,9 @@ int ring_buffer_unlock_commit(struct ring_buffer *buffer, /* * Only the last preempt count needs to restore preemption. */ - if (preempt_count() == 1) { - if (per_cpu(rb_need_resched, cpu)) - preempt_enable_no_resched_notrace(); - else - preempt_enable_notrace(); - } else + if (preempt_count() == 1) + ftrace_preempt_enable(per_cpu(rb_need_resched, cpu)); + else preempt_enable_no_resched_notrace(); return 0; @@ -1237,8 +1232,7 @@ int ring_buffer_write(struct ring_buffer *buffer, if (atomic_read(&buffer->record_disabled)) return -EBUSY; - resched = need_resched(); - preempt_disable_notrace(); + resched = ftrace_preempt_disable(); cpu = raw_smp_processor_id(); @@ -1264,10 +1258,7 @@ int ring_buffer_write(struct ring_buffer *buffer, ret = 0; out: - if (resched) - preempt_enable_no_resched_notrace(); - else - preempt_enable_notrace(); + ftrace_preempt_enable(resched); return ret; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e4c40c8..3e7bf5e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -904,8 +904,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) return; pc = preempt_count(); - resched = need_resched(); - preempt_disable_notrace(); + resched = ftrace_preempt_disable(); local_save_flags(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; @@ -915,10 +914,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) trace_function(tr, data, ip, parent_ip, flags, pc); atomic_dec(&data->disabled); - if (resched) - preempt_enable_no_resched_notrace(); - else - preempt_enable_notrace(); + ftrace_preempt_enable(resched); } static struct ftrace_ops trace_ops __read_mostly = diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 3ae93f1..7bc4abf 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -50,8 +50,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip) return; pc = preempt_count(); - resched = need_resched(); - preempt_disable_notrace(); + resched = ftrace_preempt_disable(); cpu = raw_smp_processor_id(); data = tr->data[cpu]; @@ -81,15 +80,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip) out: atomic_dec(&data->disabled); - /* - * To prevent recursion from the scheduler, if the - * resched flag was set before we entered, then - * don't reschedule. - */ - if (resched) - preempt_enable_no_resched_notrace(); - else - preempt_enable_notrace(); + ftrace_preempt_enable(resched); } static struct ftrace_ops trace_ops __read_mostly = diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index be682b6..d39e8b7 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -107,8 +107,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip) if (unlikely(!ftrace_enabled || stack_trace_disabled)) return; - resched = need_resched(); - preempt_disable_notrace(); + resched = ftrace_preempt_disable(); cpu = raw_smp_processor_id(); /* no atomic needed, we only modify this variable by this cpu */ @@ -120,10 +119,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip) out: per_cpu(trace_active, cpu)--; /* prevent recursion in schedule */ - if (resched) - preempt_enable_no_resched_notrace(); - else - preempt_enable_notrace(); + ftrace_preempt_enable(resched); } static struct ftrace_ops trace_ops __read_mostly = -- cgit v1.1 From b2a866f9344cb30d7ddf5d67b5b8393daf8bef07 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 3 Nov 2008 23:15:57 -0500 Subject: ftrace: function tracer with irqs disabled Impact: disable interrupts during trace entry creation (as opposed to preempt) To help with performance, I set the ftracer to not disable interrupts, and only to disable preemption. If an interrupt occurred, it would not be traced, because the function tracer protects itself from recursion. This may be faster, but the trace output might miss some traces. This patch makes the fuction trace disable interrupts, but it also adds a runtime feature to disable preemption instead. It does this by having two different tracer functions. When the function tracer is enabled, it will check to see which version is requested (irqs disabled or preemption disabled). Then it will use the corresponding function as the tracer. Irq disabling is the default behaviour, but if the user wants better performance, with the chance of missing traces, then they can choose the preempt disabled version. Running hackbench 3 times with the irqs disabled and 3 times with the preempt disabled function tracer yielded: tracing type times entries recorded ------------ -------- ---------------- irq disabled 43.393 166433066 43.282 166172618 43.298 166256704 preempt disabled 38.969 159871710 38.943 159972935 39.325 161056510 Average: irqs disabled: 43.324 166287462 preempt disabled: 39.079 160300385 preempt is 10.8 percent faster than irqs disabled. I wrote a patch to count function trace recursion and reran hackbench. With irq disabled: 1,150 times the function tracer did not trace due to recursion. with preempt disabled: 5,117,718 times. The thousand times with irq disabled could be due to NMIs, or simply a case where it called a function that was not protected by notrace. But we also see that a large amount of the trace is lost with the preempt version. Signed-off-by: Steven Rostedt Cc: Peter Zijlstra Cc: Andrew Morton Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 40 +++++++++++++++++++++++++++++++++++++++- kernel/trace/trace.h | 1 + 2 files changed, 40 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 3e7bf5e..d576dbd 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -244,6 +244,7 @@ static const char *trace_options[] = { "stacktrace", "sched-tree", "ftrace_printk", + "ftrace_preempt", NULL }; @@ -891,7 +892,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) #ifdef CONFIG_FUNCTION_TRACER static void -function_trace_call(unsigned long ip, unsigned long parent_ip) +function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip) { struct trace_array *tr = &global_trace; struct trace_array_cpu *data; @@ -917,6 +918,37 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) ftrace_preempt_enable(resched); } +static void +function_trace_call(unsigned long ip, unsigned long parent_ip) +{ + struct trace_array *tr = &global_trace; + struct trace_array_cpu *data; + unsigned long flags; + long disabled; + int cpu; + int pc; + + if (unlikely(!ftrace_function_enabled)) + return; + + /* + * Need to use raw, since this must be called before the + * recursive protection is performed. + */ + raw_local_irq_save(flags); + cpu = raw_smp_processor_id(); + data = tr->data[cpu]; + disabled = atomic_inc_return(&data->disabled); + + if (likely(disabled == 1)) { + pc = preempt_count(); + trace_function(tr, data, ip, parent_ip, flags, pc); + } + + atomic_dec(&data->disabled); + raw_local_irq_restore(flags); +} + static struct ftrace_ops trace_ops __read_mostly = { .func = function_trace_call, @@ -925,6 +957,12 @@ static struct ftrace_ops trace_ops __read_mostly = void tracing_start_function_trace(void) { ftrace_function_enabled = 0; + + if (trace_flags & TRACE_ITER_PREEMPTONLY) + trace_ops.func = function_trace_call_preempt_only; + else + trace_ops.func = function_trace_call; + register_ftrace_function(&trace_ops); if (tracer_enabled) ftrace_function_enabled = 1; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 10c6dae..bb547e9 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -415,6 +415,7 @@ enum trace_iterator_flags { TRACE_ITER_STACKTRACE = 0x100, TRACE_ITER_SCHED_TREE = 0x200, TRACE_ITER_PRINTK = 0x400, + TRACE_ITER_PREEMPTONLY = 0x800, }; extern struct tracer nop_trace; -- cgit v1.1 From 3299b4dd1180762da831be5eb6adc44553eaec26 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 11:58:21 +0100 Subject: ftrace: sysctl typo Impact: fix sysctl name typo Steve must have needed more coffee ;-) Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 6b6b727..65d4a9b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -487,7 +487,7 @@ static struct ctl_table kern_table[] = { #ifdef CONFIG_TRACING { .ctl_name = CTL_UNNUMBERED, - .procname = "ftrace_dump_on_opps", + .procname = "ftrace_dump_on_oops", .data = &ftrace_dump_on_oops, .maxlen = sizeof(int), .mode = 0644, -- cgit v1.1 From 71566a0d161edec70361b7f90f6e54af6a6d5d05 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 12:57:20 +0100 Subject: tracing/fastboot: Enable boot tracing only during initcalls Impact: modify boot tracer We used to disable the initcall tracing at a specified time (IE: end of builtin initcalls). But we don't need it anymore. It will be stopped when initcalls are finished. However we want two things: _Start this tracing only after pre-smp initcalls are finished. _Since we are planning to trace sched_switches at the same time, we want to enable them only during the initcall execution. For this purpose, this patch introduce two functions to enable/disable the sched_switch tracing during boot. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_boot.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index d0a5e50..d104d5b 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -13,23 +13,29 @@ #include "trace.h" static struct trace_array *boot_trace; -static int trace_boot_enabled; +static bool pre_initcalls_finished; - -/* Should be started after do_pre_smp_initcalls() in init/main.c */ +/* Tells the boot tracer that the pre_smp_initcalls are finished. + * So we are ready . + * It doesn't enable sched events tracing however. + * You have to call enable_boot_trace to do so. + */ void start_boot_trace(void) { - trace_boot_enabled = 1; + pre_initcalls_finished = true; +} + +void enable_boot_trace(void) +{ } -void stop_boot_trace(void) +void disable_boot_trace(void) { - trace_boot_enabled = 0; } void reset_boot_trace(struct trace_array *tr) { - stop_boot_trace(); + disable_boot_trace(); } static void boot_trace_init(struct trace_array *tr) @@ -37,8 +43,6 @@ static void boot_trace_init(struct trace_array *tr) int cpu; boot_trace = tr; - trace_boot_enabled = 0; - for_each_cpu_mask(cpu, cpu_possible_map) tracing_reset(tr, cpu); } @@ -46,9 +50,9 @@ static void boot_trace_init(struct trace_array *tr) static void boot_trace_ctrl_update(struct trace_array *tr) { if (tr->ctrl) - start_boot_trace(); + enable_boot_trace(); else - stop_boot_trace(); + disable_boot_trace(); } static enum print_line_t initcall_print_line(struct trace_iterator *iter) @@ -99,7 +103,7 @@ void trace_boot(struct boot_trace *it, initcall_t fn) unsigned long irq_flags; struct trace_array *tr = boot_trace; - if (!trace_boot_enabled) + if (!pre_initcalls_finished) return; /* Get its name now since this function could -- cgit v1.1 From 07695fa04e8a3384b0c855398ce1f7885bd7dc3b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 13:08:28 +0100 Subject: tracing/ftrace: fix a race condition in sched_switch tracer Impact: fix race condition in sched_switch tracer This patch fixes a race condition in the sched_switch tracer. If several tasks (IE: concurrent initcalls) are playing with tracing_start_cmdline_record() and tracing_stop_cmdline_record(), the following situation could happen: _ Task A and B are using the same tracepoint probe. Task A holds it. Task B is sleeping and doesn't hold it. _ Task A frees the sched tracer, then sched_ref is decremented to 0. _ Task A is preempted and hadn't yet unregistered its tracepoint probe, then B runs. _ B increments sched_ref, sees it's 1 and then guess it has to register its probe. But it has not been freed by task A. _ A lot of bad things can happen after that... Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_sched_switch.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index b8f56be..59de514 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -17,6 +17,7 @@ static struct trace_array *ctx_trace; static int __read_mostly tracer_enabled; static atomic_t sched_ref; +static DEFINE_MUTEX(tracepoint_mutex); static void probe_sched_switch(struct rq *__rq, struct task_struct *prev, @@ -125,18 +126,22 @@ static void tracing_start_sched_switch(void) { long ref; + mutex_lock(&tracepoint_mutex); ref = atomic_inc_return(&sched_ref); if (ref == 1) tracing_sched_register(); + mutex_unlock(&tracepoint_mutex); } static void tracing_stop_sched_switch(void) { long ref; + mutex_lock(&tracepoint_mutex); ref = atomic_dec_and_test(&sched_ref); if (ref) tracing_sched_unregister(); + mutex_unlock(&tracepoint_mutex); } void tracing_start_cmdline_record(void) -- cgit v1.1 From e55f605c14679c30be41473e60b7ad26524cdc35 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 13:14:28 +0100 Subject: tracing/ftrace: remove unused code in sched_switch tracer Impact: cleanup When init_sched_switch_trace() is called, it has no reason to start the sched tracer if the sched_ref is not zero. _ If this is non-zero, the tracer is already used, but we can register it to the tracing engine. There is already a security which avoid the tracer probes not to be resgistered twice. _ If this is zero, this block will not be used. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_sched_switch.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 59de514..96620c7 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -203,14 +203,6 @@ static struct tracer sched_switch_trace __read_mostly = __init static int init_sched_switch_trace(void) { - int ret = 0; - - if (atomic_read(&sched_ref)) - ret = tracing_sched_register(); - if (ret) { - pr_info("error registering scheduler trace\n"); - return ret; - } return register_tracer(&sched_switch_trace); } device_initcall(init_sched_switch_trace); -- cgit v1.1 From d7ad44b697c9d13e445ddc7d16f736fbac333249 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 13:20:08 +0100 Subject: tracing/fastboot: use sched switch tracer from boot tracer Impact: enhance boot trace output with scheduling events Use the sched_switch tracer from the boot tracer. We also can trace schedule events inside the initcalls. Sched tracing is disabled after the initcall has finished and then reenabled before the next one is started. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 2 ++ kernel/trace/trace.h | 1 + kernel/trace/trace_boot.c | 6 ++++++ kernel/trace/trace_sched_switch.c | 6 +++--- 4 files changed, 12 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e4c40c8..50d7018 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3251,6 +3251,8 @@ __init static int tracer_alloc_buffers(void) register_tracer(&nop_trace); #ifdef CONFIG_BOOT_TRACER + /* We don't want to launch sched_switch tracer yet */ + global_trace.ctrl = 0; register_tracer(&boot_tracer); current_trace = &boot_tracer; current_trace->init(&global_trace); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8465ad0..9911277 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -49,6 +49,7 @@ struct ftrace_entry { unsigned long parent_ip; }; extern struct tracer boot_tracer; +extern struct tracer sched_switch_trace; /* Used by the boot tracer */ /* * Context switch trace entry - which task (and prio) we switched from/to: diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index d104d5b..6bbc879 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -27,10 +27,14 @@ void start_boot_trace(void) void enable_boot_trace(void) { + if (pre_initcalls_finished) + tracing_start_cmdline_record(); } void disable_boot_trace(void) { + if (pre_initcalls_finished) + tracing_stop_cmdline_record(); } void reset_boot_trace(struct trace_array *tr) @@ -45,6 +49,8 @@ static void boot_trace_init(struct trace_array *tr) for_each_cpu_mask(cpu, cpu_possible_map) tracing_reset(tr, cpu); + + sched_switch_trace.init(tr); } static void boot_trace_ctrl_update(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 96620c7..9d7bdac 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -127,6 +127,7 @@ static void tracing_start_sched_switch(void) long ref; mutex_lock(&tracepoint_mutex); + tracer_enabled = 1; ref = atomic_inc_return(&sched_ref); if (ref == 1) tracing_sched_register(); @@ -138,6 +139,7 @@ static void tracing_stop_sched_switch(void) long ref; mutex_lock(&tracepoint_mutex); + tracer_enabled = 0; ref = atomic_dec_and_test(&sched_ref); if (ref) tracing_sched_unregister(); @@ -158,12 +160,10 @@ static void start_sched_trace(struct trace_array *tr) { sched_switch_reset(tr); tracing_start_cmdline_record(); - tracer_enabled = 1; } static void stop_sched_trace(struct trace_array *tr) { - tracer_enabled = 0; tracing_stop_cmdline_record(); } @@ -190,7 +190,7 @@ static void sched_switch_trace_ctrl_update(struct trace_array *tr) stop_sched_trace(tr); } -static struct tracer sched_switch_trace __read_mostly = +struct tracer sched_switch_trace __read_mostly = { .name = "sched_switch", .init = sched_switch_trace_init, -- cgit v1.1 From efade6e7821c4219818e9da08f9315dfa617048b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 13:28:58 +0100 Subject: tracing/ftrace: types and naming corrections for sched tracer Impact: cleanup This patch applies some corrections suggested by Steven Rostedt. Change the type of shed_ref into int since it is used into a Mutex, we don't need it anymore as an atomic variable in the sched_switch tracer. Also change the name of the register mutex. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_sched_switch.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 9d7bdac..969953b 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -16,8 +16,8 @@ static struct trace_array *ctx_trace; static int __read_mostly tracer_enabled; -static atomic_t sched_ref; -static DEFINE_MUTEX(tracepoint_mutex); +static int sched_ref; +static DEFINE_MUTEX(sched_register_mutex); static void probe_sched_switch(struct rq *__rq, struct task_struct *prev, @@ -28,7 +28,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev, int cpu; int pc; - if (!atomic_read(&sched_ref)) + if (!sched_ref) return; tracing_record_cmdline(prev); @@ -124,26 +124,22 @@ static void tracing_sched_unregister(void) static void tracing_start_sched_switch(void) { - long ref; - - mutex_lock(&tracepoint_mutex); - tracer_enabled = 1; - ref = atomic_inc_return(&sched_ref); - if (ref == 1) + mutex_lock(&sched_register_mutex); + if (!(sched_ref++)) { + tracer_enabled = 1; tracing_sched_register(); - mutex_unlock(&tracepoint_mutex); + } + mutex_unlock(&sched_register_mutex); } static void tracing_stop_sched_switch(void) { - long ref; - - mutex_lock(&tracepoint_mutex); - tracer_enabled = 0; - ref = atomic_dec_and_test(&sched_ref); - if (ref) + mutex_lock(&sched_register_mutex); + if (!(--sched_ref)) { tracing_sched_unregister(); - mutex_unlock(&tracepoint_mutex); + tracer_enabled = 0; + } + mutex_unlock(&sched_register_mutex); } void tracing_start_cmdline_record(void) -- cgit v1.1 From 79a9d461fd521f133f0e66485aa9ed09c21f5191 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 31 Oct 2008 13:34:45 +0100 Subject: tracing/ftrace: fix a bug when switch current tracer to sched tracer Impact: fix boot tracer + sched tracer coupling bug Fix a bug that made the sched_switch tracer unable to run if set as the current_tracer after the boot tracer. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_boot.c | 4 ++-- kernel/trace/trace_sched_switch.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 6bbc879..bd5046c 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -37,9 +37,9 @@ void disable_boot_trace(void) tracing_stop_cmdline_record(); } -void reset_boot_trace(struct trace_array *tr) +static void reset_boot_trace(struct trace_array *tr) { - disable_boot_trace(); + sched_switch_trace.reset(tr); } static void boot_trace_init(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 969953b..888944d 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -173,7 +173,7 @@ static void sched_switch_trace_init(struct trace_array *tr) static void sched_switch_trace_reset(struct trace_array *tr) { - if (tr->ctrl) + if (tr->ctrl && sched_ref) stop_sched_trace(tr); } -- cgit v1.1 From 60a7ecf42661f2b22168751298592da6ee210c9e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 5 Nov 2008 16:05:44 -0500 Subject: ftrace: add quick function trace stop Impact: quick start and stop of function tracer This patch adds a way to disable the function tracer quickly without the need to run kstop_machine. It adds a new variable called function_trace_stop which will stop the calls to functions from mcount when set. This is just an on/off switch and does not handle recursion like preempt_disable(). It's main purpose is to help other tracers/debuggers start and stop tracing fuctions without the need to call kstop_machine. The config option HAVE_FUNCTION_TRACE_MCOUNT_TEST is added for archs that implement the testing of the function_trace_stop in the mcount arch dependent code. Otherwise, the test is done in the C code. x86 is the only arch at the moment that supports this. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 7 +++++++ kernel/trace/ftrace.c | 47 +++++++++++++++++++++++++++++++++++++---------- 2 files changed, 44 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 33dbefd..fc4febc 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -9,6 +9,13 @@ config NOP_TRACER config HAVE_FUNCTION_TRACER bool +config HAVE_FUNCTION_TRACE_MCOUNT_TEST + bool + help + This gets selected when the arch tests the function_trace_stop + variable at the mcount call site. Otherwise, this variable + is tested by the called function. + config HAVE_DYNAMIC_FTRACE bool diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4a39d24..896c71f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -47,6 +47,9 @@ int ftrace_enabled __read_mostly; static int last_ftrace_enabled; +/* Quick disabling of function tracer. */ +int function_trace_stop; + /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. @@ -63,6 +66,7 @@ static struct ftrace_ops ftrace_list_end __read_mostly = static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; +ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) { @@ -88,8 +92,23 @@ static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) void clear_ftrace_function(void) { ftrace_trace_function = ftrace_stub; + __ftrace_trace_function = ftrace_stub; } +#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST +/* + * For those archs that do not test ftrace_trace_stop in their + * mcount call site, we need to do it from C. + */ +static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip) +{ + if (function_trace_stop) + return; + + __ftrace_trace_function(ip, parent_ip); +} +#endif + static int __register_ftrace_function(struct ftrace_ops *ops) { /* should not be called from interrupt context */ @@ -110,10 +129,18 @@ static int __register_ftrace_function(struct ftrace_ops *ops) * For one func, simply call it directly. * For more than one func, call the chain. */ +#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST if (ops->next == &ftrace_list_end) ftrace_trace_function = ops->func; else ftrace_trace_function = ftrace_list_func; +#else + if (ops->next == &ftrace_list_end) + __ftrace_trace_function = ops->func; + else + __ftrace_trace_function = ftrace_list_func; + ftrace_trace_function = ftrace_test_stop_func; +#endif } spin_unlock(&ftrace_lock); @@ -526,7 +553,7 @@ static void ftrace_run_update_code(int command) } static ftrace_func_t saved_ftrace_func; -static int ftrace_start; +static int ftrace_start_up; static DEFINE_MUTEX(ftrace_start_lock); static void ftrace_startup(void) @@ -537,8 +564,8 @@ static void ftrace_startup(void) return; mutex_lock(&ftrace_start_lock); - ftrace_start++; - if (ftrace_start == 1) + ftrace_start_up++; + if (ftrace_start_up == 1) command |= FTRACE_ENABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { @@ -562,8 +589,8 @@ static void ftrace_shutdown(void) return; mutex_lock(&ftrace_start_lock); - ftrace_start--; - if (!ftrace_start) + ftrace_start_up--; + if (!ftrace_start_up) command |= FTRACE_DISABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { @@ -589,8 +616,8 @@ static void ftrace_startup_sysctl(void) mutex_lock(&ftrace_start_lock); /* Force update next time */ saved_ftrace_func = NULL; - /* ftrace_start is true if we want ftrace running */ - if (ftrace_start) + /* ftrace_start_up is true if we want ftrace running */ + if (ftrace_start_up) command |= FTRACE_ENABLE_CALLS; ftrace_run_update_code(command); @@ -605,8 +632,8 @@ static void ftrace_shutdown_sysctl(void) return; mutex_lock(&ftrace_start_lock); - /* ftrace_start is true if ftrace is running */ - if (ftrace_start) + /* ftrace_start_up is true if ftrace is running */ + if (ftrace_start_up) command |= FTRACE_DISABLE_CALLS; ftrace_run_update_code(command); @@ -1186,7 +1213,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) mutex_lock(&ftrace_sysctl_lock); mutex_lock(&ftrace_start_lock); - if (iter->filtered && ftrace_start && ftrace_enabled) + if (iter->filtered && ftrace_start_up && ftrace_enabled) ftrace_run_update_code(FTRACE_ENABLE_CALLS); mutex_unlock(&ftrace_start_lock); mutex_unlock(&ftrace_sysctl_lock); -- cgit v1.1 From 0f04870148ecb825133bc2733f473b1c5773ac0b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 5 Nov 2008 16:05:44 -0500 Subject: ftrace: soft tracing stop and start Impact: add way to quickly start stop tracing from the kernel This patch adds a soft stop and start to the trace. This simply disables function tracing via the ftrace_disabled flag, and disables the trace buffers to prevent recording. The tracing code may still be executed, but the trace will not be recorded. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 79 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 29ab40a..113aea9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -43,6 +43,15 @@ unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX; unsigned long __read_mostly tracing_thresh; + +/* + * Kill all tracing for good (never come back). + * It is initialized to 1 but will turn to zero if the initialization + * of the tracer is successful. But that is the only place that sets + * this back to zero. + */ +int tracing_disabled = 1; + static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled); static inline void ftrace_disable_cpu(void) @@ -62,8 +71,6 @@ static cpumask_t __read_mostly tracing_buffer_mask; #define for_each_tracing_cpu(cpu) \ for_each_cpu_mask(cpu, tracing_buffer_mask) -static int tracing_disabled = 1; - /* * ftrace_dump_on_oops - variable to dump ftrace buffer on oops * @@ -613,6 +620,76 @@ static void trace_init_cmdlines(void) cmdline_idx = 0; } +static int trace_stop_count; +static DEFINE_SPINLOCK(tracing_start_lock); + +/** + * tracing_start - quick start of the tracer + * + * If tracing is enabled but was stopped by tracing_stop, + * this will start the tracer back up. + */ +void tracing_start(void) +{ + struct ring_buffer *buffer; + unsigned long flags; + + if (tracing_disabled) + return; + + spin_lock_irqsave(&tracing_start_lock, flags); + if (--trace_stop_count) + goto out; + + if (trace_stop_count < 0) { + /* Someone screwed up their debugging */ + WARN_ON_ONCE(1); + trace_stop_count = 0; + goto out; + } + + + buffer = global_trace.buffer; + if (buffer) + ring_buffer_record_enable(buffer); + + buffer = max_tr.buffer; + if (buffer) + ring_buffer_record_enable(buffer); + + ftrace_start(); + out: + spin_unlock_irqrestore(&tracing_start_lock, flags); +} + +/** + * tracing_stop - quick stop of the tracer + * + * Light weight way to stop tracing. Use in conjunction with + * tracing_start. + */ +void tracing_stop(void) +{ + struct ring_buffer *buffer; + unsigned long flags; + + ftrace_stop(); + spin_lock_irqsave(&tracing_start_lock, flags); + if (trace_stop_count++) + goto out; + + buffer = global_trace.buffer; + if (buffer) + ring_buffer_record_disable(buffer); + + buffer = max_tr.buffer; + if (buffer) + ring_buffer_record_disable(buffer); + + out: + spin_unlock_irqrestore(&tracing_start_lock, flags); +} + void trace_stop_cmdline_recording(void); static void trace_save_cmdline(struct task_struct *tsk) -- cgit v1.1 From 9036990d462e09366f7297a2d1da6582c3e6b1d3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 5 Nov 2008 16:05:44 -0500 Subject: ftrace: restructure tracing start/stop infrastructure Impact: change where tracing is started up and stopped Currently, when a new tracer is selected via echo'ing a tracer name into the current_tracer file, the startup is only done if tracing_enabled is set to one. If tracing_enabled is changed to zero (by echo'ing 0 into the tracing_enabled file) a full shutdown is performed. The full startup and shutdown of a tracer can be expensive and the user can lose out traces when echo'ing in 0 to the tracing_enabled file, because the process takes too long. There can also be places that the user would like to start and stop the tracer several times and doing the full startup and shutdown of a tracer might be too expensive. This patch performs the full startup and shutdown when a tracer is selected. It also adds a way to do a quick start or stop of a tracer. The quick version is just a flag that prevents the tracing from taking place, but the overhead of the code is still there. For example, the startup of a tracer may enable tracepoints, or enable the function tracer. The stop and start will just set a flag to have the tracer ignore the calls when the tracepoint or function trace is called. The overhead of the tracer may still be present when the tracer is stopped, but no tracing will occur. Setting the tracer to the 'nop' tracer (or any other tracer) will perform the shutdown of the tracer which will disable the tracepoint or disable the function tracer. The tracing_enabled file will simply start or stop tracing. This change is all internal. The end result for the user should be the same as before. If tracing_enabled is not set, no trace will happen. If tracing_enabled is set, then the trace will happen. The tracing_enabled variable is static between tracers. Enabling tracing_enabled and going to another tracer will keep tracing_enabled enabled. Same is true with disabling tracing_enabled. This patch will now provide a fast start/stop method to the users for enabling or disabling tracing. Note: There were two methods to the struct tracer that were never used: The methods start and stop. These were to be used as a hook to the reading of the trace output, but ended up not being necessary. These two methods are now used to enable the start and stop of each tracer, in case the tracer needs to do more than just not write into the buffer. For example, the irqsoff tracer must stop recording max latencies when tracing is stopped. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 64 +++++++++++++++++---------------------- kernel/trace/trace.h | 5 +-- kernel/trace/trace_functions.c | 6 ++++ kernel/trace/trace_irqsoff.c | 41 ++++++++++++++++++++++--- kernel/trace/trace_sched_switch.c | 13 ++++++++ kernel/trace/trace_sched_wakeup.c | 39 +++++++++++++++++++++--- 6 files changed, 120 insertions(+), 48 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 113aea9..ff1e9ed 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -150,6 +150,19 @@ static DEFINE_PER_CPU(struct trace_array_cpu, max_data); /* tracer_enabled is used to toggle activation of a tracer */ static int tracer_enabled = 1; +/** + * tracing_is_enabled - return tracer_enabled status + * + * This function is used by other tracers to know the status + * of the tracer_enabled flag. Tracers may use this function + * to know if it should enable their features when starting + * up. See irqsoff tracer for an example (start_irqsoff_tracer). + */ +int tracing_is_enabled(void) +{ + return tracer_enabled; +} + /* function tracing enabled */ int ftrace_function_enabled; @@ -1041,8 +1054,7 @@ void tracing_start_function_trace(void) trace_ops.func = function_trace_call; register_ftrace_function(&trace_ops); - if (tracer_enabled) - ftrace_function_enabled = 1; + ftrace_function_enabled = 1; } void tracing_stop_function_trace(void) @@ -1189,10 +1201,6 @@ static void *s_start(struct seq_file *m, loff_t *pos) atomic_inc(&trace_record_cmdline_disabled); - /* let the tracer grab locks here if needed */ - if (current_trace->start) - current_trace->start(iter); - if (*pos != iter->pos) { iter->ent = NULL; iter->cpu = 0; @@ -1219,14 +1227,7 @@ static void *s_start(struct seq_file *m, loff_t *pos) static void s_stop(struct seq_file *m, void *p) { - struct trace_iterator *iter = m->private; - atomic_dec(&trace_record_cmdline_disabled); - - /* let the tracer release locks here if needed */ - if (current_trace && current_trace == iter->trace && iter->trace->stop) - iter->trace->stop(iter); - mutex_unlock(&trace_types_lock); } @@ -2056,10 +2057,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) m->private = iter; /* stop the trace while dumping */ - if (iter->tr->ctrl) { - tracer_enabled = 0; - ftrace_function_enabled = 0; - } + tracing_stop(); if (iter->trace && iter->trace->open) iter->trace->open(iter); @@ -2104,14 +2102,7 @@ int tracing_release(struct inode *inode, struct file *file) iter->trace->close(iter); /* reenable tracing if it was previously enabled */ - if (iter->tr->ctrl) { - tracer_enabled = 1; - /* - * It is safe to enable function tracing even if it - * isn't used - */ - ftrace_function_enabled = 1; - } + tracing_start(); mutex_unlock(&trace_types_lock); seq_release(inode, file); @@ -2449,11 +2440,10 @@ static ssize_t tracing_ctrl_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_array *tr = filp->private_data; char buf[64]; int r; - r = sprintf(buf, "%ld\n", tr->ctrl); + r = sprintf(buf, "%u\n", tracer_enabled); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } @@ -2481,16 +2471,18 @@ tracing_ctrl_write(struct file *filp, const char __user *ubuf, val = !!val; mutex_lock(&trace_types_lock); - if (tr->ctrl ^ val) { - if (val) + if (tracer_enabled ^ val) { + if (val) { tracer_enabled = 1; - else + if (current_trace->start) + current_trace->start(tr); + tracing_start(); + } else { tracer_enabled = 0; - - tr->ctrl = val; - - if (current_trace && current_trace->ctrl_update) - current_trace->ctrl_update(tr); + tracing_stop(); + if (current_trace->stop) + current_trace->stop(tr); + } } mutex_unlock(&trace_types_lock); @@ -3372,7 +3364,7 @@ __init static int tracer_alloc_buffers(void) #endif /* All seems OK, enable tracing */ - global_trace.ctrl = tracer_enabled; + global_trace.ctrl = 1; tracing_disabled = 0; atomic_notifier_chain_register(&panic_notifier_list, diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index cc14a6b..3422489 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -237,11 +237,11 @@ struct tracer { const char *name; void (*init)(struct trace_array *tr); void (*reset)(struct trace_array *tr); + void (*start)(struct trace_array *tr); + void (*stop)(struct trace_array *tr); void (*open)(struct trace_iterator *iter); void (*pipe_open)(struct trace_iterator *iter); void (*close)(struct trace_iterator *iter); - void (*start)(struct trace_iterator *iter); - void (*stop)(struct trace_iterator *iter); ssize_t (*read)(struct trace_iterator *iter, struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos); @@ -282,6 +282,7 @@ struct trace_iterator { long idx; }; +int tracing_is_enabled(void); void trace_wake_up(void); void tracing_reset(struct trace_array *tr, int cpu); int tracing_open_generic(struct inode *inode, struct file *filp); diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 0f85a64..9f1b0de 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -62,11 +62,17 @@ static void function_trace_ctrl_update(struct trace_array *tr) stop_function_trace(tr); } +static void function_trace_start(struct trace_array *tr) +{ + function_reset(tr); +} + static struct tracer function_trace __read_mostly = { .name = "function", .init = function_trace_init, .reset = function_trace_reset, + .start = function_trace_start, .ctrl_update = function_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_function, diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 9c74071..a87a20f 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -353,15 +353,28 @@ void trace_preempt_off(unsigned long a0, unsigned long a1) } #endif /* CONFIG_PREEMPT_TRACER */ +/* + * save_tracer_enabled is used to save the state of the tracer_enabled + * variable when we disable it when we open a trace output file. + */ +static int save_tracer_enabled; + static void start_irqsoff_tracer(struct trace_array *tr) { register_ftrace_function(&trace_ops); - tracer_enabled = 1; + if (tracing_is_enabled()) { + tracer_enabled = 1; + save_tracer_enabled = 1; + } else { + tracer_enabled = 0; + save_tracer_enabled = 0; + } } static void stop_irqsoff_tracer(struct trace_array *tr) { tracer_enabled = 0; + save_tracer_enabled = 0; unregister_ftrace_function(&trace_ops); } @@ -389,17 +402,29 @@ static void irqsoff_tracer_ctrl_update(struct trace_array *tr) stop_irqsoff_tracer(tr); } +static void irqsoff_tracer_start(struct trace_array *tr) +{ + irqsoff_tracer_reset(tr); + tracer_enabled = 1; + save_tracer_enabled = 1; +} + +static void irqsoff_tracer_stop(struct trace_array *tr) +{ + tracer_enabled = 0; + save_tracer_enabled = 0; +} + static void irqsoff_tracer_open(struct trace_iterator *iter) { /* stop the trace while dumping */ - if (iter->tr->ctrl) - stop_irqsoff_tracer(iter->tr); + tracer_enabled = 0; } static void irqsoff_tracer_close(struct trace_iterator *iter) { - if (iter->tr->ctrl) - start_irqsoff_tracer(iter->tr); + /* restart tracing */ + tracer_enabled = save_tracer_enabled; } #ifdef CONFIG_IRQSOFF_TRACER @@ -414,6 +439,8 @@ static struct tracer irqsoff_tracer __read_mostly = .name = "irqsoff", .init = irqsoff_tracer_init, .reset = irqsoff_tracer_reset, + .start = irqsoff_tracer_start, + .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, .ctrl_update = irqsoff_tracer_ctrl_update, @@ -440,6 +467,8 @@ static struct tracer preemptoff_tracer __read_mostly = .name = "preemptoff", .init = preemptoff_tracer_init, .reset = irqsoff_tracer_reset, + .start = irqsoff_tracer_start, + .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, .ctrl_update = irqsoff_tracer_ctrl_update, @@ -468,6 +497,8 @@ static struct tracer preemptirqsoff_tracer __read_mostly = .name = "preemptirqsoff", .init = preemptirqsoff_tracer_init, .reset = irqsoff_tracer_reset, + .start = irqsoff_tracer_start, + .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, .ctrl_update = irqsoff_tracer_ctrl_update, diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 888944d..91c699b 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -186,11 +186,24 @@ static void sched_switch_trace_ctrl_update(struct trace_array *tr) stop_sched_trace(tr); } +static void sched_switch_trace_start(struct trace_array *tr) +{ + sched_switch_reset(tr); + tracing_start_sched_switch(); +} + +static void sched_switch_trace_stop(struct trace_array *tr) +{ + tracing_stop_sched_switch(); +} + struct tracer sched_switch_trace __read_mostly = { .name = "sched_switch", .init = sched_switch_trace_init, .reset = sched_switch_trace_reset, + .start = sched_switch_trace_start, + .stop = sched_switch_trace_stop, .ctrl_update = sched_switch_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_sched_switch, diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 7bc4abf..240577b 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -262,6 +262,12 @@ out: atomic_dec(&wakeup_trace->data[cpu]->disabled); } +/* + * save_tracer_enabled is used to save the state of the tracer_enabled + * variable when we disable it when we open a trace output file. + */ +static int save_tracer_enabled; + static void start_wakeup_tracer(struct trace_array *tr) { int ret; @@ -300,7 +306,13 @@ static void start_wakeup_tracer(struct trace_array *tr) register_ftrace_function(&trace_ops); - tracer_enabled = 1; + if (tracing_is_enabled()) { + tracer_enabled = 1; + save_tracer_enabled = 1; + } else { + tracer_enabled = 0; + save_tracer_enabled = 0; + } return; fail_deprobe_wake_new: @@ -312,6 +324,7 @@ fail_deprobe: static void stop_wakeup_tracer(struct trace_array *tr) { tracer_enabled = 0; + save_tracer_enabled = 0; unregister_ftrace_function(&trace_ops); unregister_trace_sched_switch(probe_wakeup_sched_switch); unregister_trace_sched_wakeup_new(probe_wakeup); @@ -343,18 +356,32 @@ static void wakeup_tracer_ctrl_update(struct trace_array *tr) stop_wakeup_tracer(tr); } +static void wakeup_tracer_start(struct trace_array *tr) +{ + wakeup_reset(tr); + tracer_enabled = 1; + save_tracer_enabled = 1; +} + +static void wakeup_tracer_stop(struct trace_array *tr) +{ + tracer_enabled = 0; + save_tracer_enabled = 0; +} + static void wakeup_tracer_open(struct trace_iterator *iter) { /* stop the trace while dumping */ - if (iter->tr->ctrl) - stop_wakeup_tracer(iter->tr); + tracer_enabled = 0; } static void wakeup_tracer_close(struct trace_iterator *iter) { /* forget about any processes we were recording */ - if (iter->tr->ctrl) - start_wakeup_tracer(iter->tr); + if (save_tracer_enabled) { + wakeup_reset(iter->tr); + tracer_enabled = 1; + } } static struct tracer wakeup_tracer __read_mostly = @@ -362,6 +389,8 @@ static struct tracer wakeup_tracer __read_mostly = .name = "wakeup", .init = wakeup_tracer_init, .reset = wakeup_tracer_reset, + .start = wakeup_tracer_start, + .stop = wakeup_tracer_stop, .open = wakeup_tracer_open, .close = wakeup_tracer_close, .ctrl_update = wakeup_tracer_ctrl_update, -- cgit v1.1 From 3e03fb7f1da2e691644526c0d6df42d778716349 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 6 Nov 2008 00:09:43 -0500 Subject: ring-buffer: convert to raw spinlocks Impact: no lockdep debugging of ring buffer The problem with running lockdep on the ring buffer is that the ring buffer is the core infrastructure of ftrace. What happens is that the tracer will start tracing the lockdep code while lockdep is testing the ring buffers locks. This can cause lockdep to fail due to testing cases that have not fully finished their locking transition. This patch converts the spin locks used by the ring buffer back into raw spin locks which lockdep does not check. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 151f6a7..a2dea50 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -154,7 +154,7 @@ static inline int test_time_stamp(u64 delta) struct ring_buffer_per_cpu { int cpu; struct ring_buffer *buffer; - spinlock_t lock; + raw_spinlock_t lock; struct lock_class_key lock_key; struct list_head pages; struct buffer_page *head_page; /* read from head */ @@ -291,7 +291,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu) cpu_buffer->cpu = cpu; cpu_buffer->buffer = buffer; - spin_lock_init(&cpu_buffer->lock); + cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; INIT_LIST_HEAD(&cpu_buffer->pages); page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()), @@ -854,7 +854,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, if (write > BUF_PAGE_SIZE) { struct buffer_page *next_page = tail_page; - spin_lock_irqsave(&cpu_buffer->lock, flags); + local_irq_save(flags); + __raw_spin_lock(&cpu_buffer->lock); rb_inc_page(cpu_buffer, &next_page); @@ -930,7 +931,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, rb_set_commit_to_write(cpu_buffer); } - spin_unlock_irqrestore(&cpu_buffer->lock, flags); + __raw_spin_unlock(&cpu_buffer->lock); + local_irq_restore(flags); /* fail and let the caller try again */ return ERR_PTR(-EAGAIN); @@ -953,7 +955,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, return event; out_unlock: - spin_unlock_irqrestore(&cpu_buffer->lock, flags); + __raw_spin_unlock(&cpu_buffer->lock); + local_irq_restore(flags); return NULL; } @@ -1524,7 +1527,8 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) struct buffer_page *reader = NULL; unsigned long flags; - spin_lock_irqsave(&cpu_buffer->lock, flags); + local_irq_save(flags); + __raw_spin_lock(&cpu_buffer->lock); again: reader = cpu_buffer->reader_page; @@ -1574,7 +1578,8 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) goto again; out: - spin_unlock_irqrestore(&cpu_buffer->lock, flags); + __raw_spin_unlock(&cpu_buffer->lock); + local_irq_restore(flags); return reader; } @@ -1815,9 +1820,11 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu) atomic_inc(&cpu_buffer->record_disabled); synchronize_sched(); - spin_lock_irqsave(&cpu_buffer->lock, flags); + local_irq_save(flags); + __raw_spin_lock(&cpu_buffer->lock); ring_buffer_iter_reset(iter); - spin_unlock_irqrestore(&cpu_buffer->lock, flags); + __raw_spin_unlock(&cpu_buffer->lock); + local_irq_restore(flags); return iter; } @@ -1903,11 +1910,13 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu) if (!cpu_isset(cpu, buffer->cpumask)) return; - spin_lock_irqsave(&cpu_buffer->lock, flags); + local_irq_save(flags); + __raw_spin_lock(&cpu_buffer->lock); rb_reset_cpu(cpu_buffer); - spin_unlock_irqrestore(&cpu_buffer->lock, flags); + __raw_spin_unlock(&cpu_buffer->lock); + local_irq_restore(flags); } /** -- cgit v1.1 From 0183fb1c94b74862b073590fc52c56b7364b7bad Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: fix set_ftrace_filter Impact: fix of output of set_ftrace_filter Commit ftrace: do not show freed records in available_filter_functions Removed a bit too much from the set_ftrace_filter code, where we now see all functions in the set_ftrace_filter file even when we set a filter. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 896c71f..4d2e751 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -765,6 +765,9 @@ t_next(struct seq_file *m, void *v, loff_t *pos) ((iter->flags & FTRACE_ITER_FAILURES) && !(rec->flags & FTRACE_FL_FAILED)) || + ((iter->flags & FTRACE_ITER_FILTER) && + !(rec->flags & FTRACE_FL_FILTER)) || + ((iter->flags & FTRACE_ITER_NOTRACE) && !(rec->flags & FTRACE_FL_NOTRACE))) { rec = NULL; -- cgit v1.1 From 75f5c47da386445ba0c5a8b7e3ca0c906e763369 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: fix boot trace sched startup Impact: boot tracer startup modified The boot tracer calls into some of the schedule tracing private functions that should not be exported. This patch cleans it up, and makes way for further changes in the ftrace infrastructure. This patch adds a api to assign a tracer array to the schedule context switch tracer. Signed-off-by: Steven Rostedt Acked-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 2 +- kernel/trace/trace_boot.c | 9 +++++++-- kernel/trace/trace_sched_switch.c | 15 ++++++++++++++- 3 files changed, 22 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 3422489..db12e16 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -49,7 +49,6 @@ struct ftrace_entry { unsigned long parent_ip; }; extern struct tracer boot_tracer; -extern struct tracer sched_switch_trace; /* Used by the boot tracer */ /* * Context switch trace entry - which task (and prio) we switched from/to: @@ -325,6 +324,7 @@ void trace_function(struct trace_array *tr, void tracing_start_cmdline_record(void); void tracing_stop_cmdline_record(void); +void tracing_cmdline_assign_trace(struct trace_array *tr); int register_tracer(struct tracer *type); void unregister_tracer(struct tracer *type); diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index bd5046c..662cb91 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -39,7 +39,12 @@ void disable_boot_trace(void) static void reset_boot_trace(struct trace_array *tr) { - sched_switch_trace.reset(tr); + int cpu; + + tr->time_start = ftrace_now(tr->cpu); + + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); } static void boot_trace_init(struct trace_array *tr) @@ -50,7 +55,7 @@ static void boot_trace_init(struct trace_array *tr) for_each_cpu_mask(cpu, cpu_possible_map) tracing_reset(tr, cpu); - sched_switch_trace.init(tr); + tracing_cmdline_assign_trace(tr); } static void boot_trace_ctrl_update(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 91c699b..fbf05df 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -152,6 +152,19 @@ void tracing_stop_cmdline_record(void) tracing_stop_sched_switch(); } +/** + * tracing_cmdline_assign_trace - assign a trace array for ctx switch + * @tr: trace array pointer to assign + * + * Some tracers might want to record the context switches in their + * trace. This function lets those tracers assign the trace array + * to use. + */ +void tracing_cmdline_assign_trace(struct trace_array *tr) +{ + ctx_trace = tr; +} + static void start_sched_trace(struct trace_array *tr) { sched_switch_reset(tr); @@ -197,7 +210,7 @@ static void sched_switch_trace_stop(struct trace_array *tr) tracing_stop_sched_switch(); } -struct tracer sched_switch_trace __read_mostly = +static struct tracer sched_switch_trace __read_mostly = { .name = "sched_switch", .init = sched_switch_trace_init, -- cgit v1.1 From e168e0516e476070faa9e8e7b23dfcba79b76d82 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: fix sched_switch API Impact: fix for sched_switch that broke dynamic ftrace startup The commit: tracing/fastboot: use sched switch tracer from boot tracer broke the API of the sched_switch trace. The use of the tracing_start/stop_cmdline record is for only recording the cmdline, NOT recording the schedule switches themselves. Seeing that the boot tracer broke the API to do something that it wanted, this patch adds a new interface for the API while puting back the original interface of the old API. Signed-off-by: Steven Rostedt Acked-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 4 +++- kernel/trace/trace_boot.c | 6 ++--- kernel/trace/trace_sched_switch.c | 50 +++++++++++++++++++++++++++++++-------- 3 files changed, 46 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index db12e16..25abfc4 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -324,7 +324,9 @@ void trace_function(struct trace_array *tr, void tracing_start_cmdline_record(void); void tracing_stop_cmdline_record(void); -void tracing_cmdline_assign_trace(struct trace_array *tr); +void tracing_sched_switch_assign_trace(struct trace_array *tr); +void tracing_stop_sched_switch_record(void); +void tracing_start_sched_switch_record(void); int register_tracer(struct tracer *type); void unregister_tracer(struct tracer *type); diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 662cb91..0203c10 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -28,13 +28,13 @@ void start_boot_trace(void) void enable_boot_trace(void) { if (pre_initcalls_finished) - tracing_start_cmdline_record(); + tracing_start_sched_switch_record(); } void disable_boot_trace(void) { if (pre_initcalls_finished) - tracing_stop_cmdline_record(); + tracing_stop_sched_switch_record(); } static void reset_boot_trace(struct trace_array *tr) @@ -55,7 +55,7 @@ static void boot_trace_init(struct trace_array *tr) for_each_cpu_mask(cpu, cpu_possible_map) tracing_reset(tr, cpu); - tracing_cmdline_assign_trace(tr); + tracing_sched_switch_assign_trace(tr); } static void boot_trace_ctrl_update(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index fbf05df..79410db 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -125,20 +125,16 @@ static void tracing_sched_unregister(void) static void tracing_start_sched_switch(void) { mutex_lock(&sched_register_mutex); - if (!(sched_ref++)) { - tracer_enabled = 1; + if (!(sched_ref++)) tracing_sched_register(); - } mutex_unlock(&sched_register_mutex); } static void tracing_stop_sched_switch(void) { mutex_lock(&sched_register_mutex); - if (!(--sched_ref)) { + if (!(--sched_ref)) tracing_sched_unregister(); - tracer_enabled = 0; - } mutex_unlock(&sched_register_mutex); } @@ -153,14 +149,48 @@ void tracing_stop_cmdline_record(void) } /** - * tracing_cmdline_assign_trace - assign a trace array for ctx switch + * tracing_start_sched_switch_record - start tracing context switches + * + * Turns on context switch tracing for a tracer. + */ +void tracing_start_sched_switch_record(void) +{ + if (unlikely(!ctx_trace)) { + WARN_ON(1); + return; + } + + tracing_start_sched_switch(); + + mutex_lock(&sched_register_mutex); + tracer_enabled++; + mutex_unlock(&sched_register_mutex); +} + +/** + * tracing_stop_sched_switch_record - start tracing context switches + * + * Turns off context switch tracing for a tracer. + */ +void tracing_stop_sched_switch_record(void) +{ + mutex_lock(&sched_register_mutex); + tracer_enabled--; + WARN_ON(tracer_enabled < 0); + mutex_unlock(&sched_register_mutex); + + tracing_stop_sched_switch(); +} + +/** + * tracing_sched_switch_assign_trace - assign a trace array for ctx switch * @tr: trace array pointer to assign * * Some tracers might want to record the context switches in their * trace. This function lets those tracers assign the trace array * to use. */ -void tracing_cmdline_assign_trace(struct trace_array *tr) +void tracing_sched_switch_assign_trace(struct trace_array *tr) { ctx_trace = tr; } @@ -168,12 +198,12 @@ void tracing_cmdline_assign_trace(struct trace_array *tr) static void start_sched_trace(struct trace_array *tr) { sched_switch_reset(tr); - tracing_start_cmdline_record(); + tracing_start_sched_switch_record(); } static void stop_sched_trace(struct trace_array *tr) { - tracing_stop_cmdline_record(); + tracing_stop_sched_switch_record(); } static void sched_switch_trace_init(struct trace_array *tr) -- cgit v1.1 From 451931702017951f74624ddc4f7f02e4641b0e20 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: irqsoff tracer incorrect reset Impact: fix to irqsoff tracer output In converting to the new start / stop ftrace handling, the irqsoff tracer start called the irqsoff reset function. irqsoff tracer is not the same as the other traces, and it resets the buffers while searching for the longest latency. The reset that the irqsoff stop method calls disables the function tracing. That means that, by starting the tracer, the function tracer is disabled incorrectly. This patch simply removes the call to reset which keeps the function tracing enabled. Reset is not needed for the irqsoff stop method. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_irqsoff.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index a87a20f..3509086 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -404,7 +404,6 @@ static void irqsoff_tracer_ctrl_update(struct trace_array *tr) static void irqsoff_tracer_start(struct trace_array *tr) { - irqsoff_tracer_reset(tr); tracer_enabled = 1; save_tracer_enabled = 1; } -- cgit v1.1 From 49833fc232bd6a5076496994d855f601354501d7 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: enable trace_printk by default Impact: have the ftrace_printk enabled on startup It is confusing to have to "echo trace_printk > /debug/tracing/iter_ctrl" after adding ftrace_printk in the kernel. Currently the trace_printk is set to off by default. ftrace_printk should only be in open kernel code when used for debugging, and thus it should be enabled by default. It may also be used to record data within a tracer, but those ftrace_printks should be within wrappers that are either enabled by trace_points or have a variable protecting the code path from being entered when the tracer is disabled. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d55ccfc..dbbdacf 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -205,7 +205,7 @@ static DEFINE_MUTEX(trace_types_lock); static DECLARE_WAIT_QUEUE_HEAD(trace_wait); /* trace_flags holds iter_ctrl options */ -unsigned long trace_flags = TRACE_ITER_PRINT_PARENT; +unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK; /** * trace_wake_up - wake up tasks waiting for trace input -- cgit v1.1 From bbf5b1a0cecb56de6236db8b01c5bfb7ab8ba8b2 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: remove ctrl_update method Impact: Remove the ctrl_update tracer method With the new quick start/stop method of tracing, the ctrl_update method is out of date. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 2 -- kernel/trace/trace.h | 1 - kernel/trace/trace_boot.c | 9 -------- kernel/trace/trace_functions.c | 9 -------- kernel/trace/trace_irqsoff.c | 11 --------- kernel/trace/trace_mmiotrace.c | 11 +++------ kernel/trace/trace_nop.c | 10 -------- kernel/trace/trace_sched_switch.c | 10 -------- kernel/trace/trace_sched_wakeup.c | 9 -------- kernel/trace/trace_selftest.c | 48 +++++++++++++++++++++------------------ kernel/trace/trace_sysprof.c | 10 -------- 11 files changed, 29 insertions(+), 101 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dbbdacf..9e83188 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3357,8 +3357,6 @@ __init static int tracer_alloc_buffers(void) register_tracer(&nop_trace); #ifdef CONFIG_BOOT_TRACER - /* We don't want to launch sched_switch tracer yet */ - global_trace.ctrl = 0; register_tracer(&boot_tracer); current_trace = &boot_tracer; current_trace->init(&global_trace); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 25abfc4..e481eda 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -244,7 +244,6 @@ struct tracer { ssize_t (*read)(struct trace_iterator *iter, struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos); - void (*ctrl_update)(struct trace_array *tr); #ifdef CONFIG_FTRACE_STARTUP_TEST int (*selftest)(struct tracer *trace, struct trace_array *tr); diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 0203c10..8f71915 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -58,14 +58,6 @@ static void boot_trace_init(struct trace_array *tr) tracing_sched_switch_assign_trace(tr); } -static void boot_trace_ctrl_update(struct trace_array *tr) -{ - if (tr->ctrl) - enable_boot_trace(); - else - disable_boot_trace(); -} - static enum print_line_t initcall_print_line(struct trace_iterator *iter) { int ret; @@ -102,7 +94,6 @@ struct tracer boot_tracer __read_mostly = .name = "initcall", .init = boot_trace_init, .reset = reset_boot_trace, - .ctrl_update = boot_trace_ctrl_update, .print_line = initcall_print_line, }; diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 9f1b0de..e980b87 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -54,14 +54,6 @@ static void function_trace_reset(struct trace_array *tr) stop_function_trace(tr); } -static void function_trace_ctrl_update(struct trace_array *tr) -{ - if (tr->ctrl) - start_function_trace(tr); - else - stop_function_trace(tr); -} - static void function_trace_start(struct trace_array *tr) { function_reset(tr); @@ -73,7 +65,6 @@ static struct tracer function_trace __read_mostly = .init = function_trace_init, .reset = function_trace_reset, .start = function_trace_start, - .ctrl_update = function_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_function, #endif diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 3509086..ffdf592 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -394,14 +394,6 @@ static void irqsoff_tracer_reset(struct trace_array *tr) stop_irqsoff_tracer(tr); } -static void irqsoff_tracer_ctrl_update(struct trace_array *tr) -{ - if (tr->ctrl) - start_irqsoff_tracer(tr); - else - stop_irqsoff_tracer(tr); -} - static void irqsoff_tracer_start(struct trace_array *tr) { tracer_enabled = 1; @@ -442,7 +434,6 @@ static struct tracer irqsoff_tracer __read_mostly = .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, - .ctrl_update = irqsoff_tracer_ctrl_update, .print_max = 1, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_irqsoff, @@ -470,7 +461,6 @@ static struct tracer preemptoff_tracer __read_mostly = .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, - .ctrl_update = irqsoff_tracer_ctrl_update, .print_max = 1, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_preemptoff, @@ -500,7 +490,6 @@ static struct tracer preemptirqsoff_tracer __read_mostly = .stop = irqsoff_tracer_stop, .open = irqsoff_tracer_open, .close = irqsoff_tracer_close, - .ctrl_update = irqsoff_tracer_ctrl_update, .print_max = 1, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_preemptirqsoff, diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index f284846..fa9354e 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -49,15 +49,10 @@ static void mmio_trace_reset(struct trace_array *tr) mmio_trace_array = NULL; } -static void mmio_trace_ctrl_update(struct trace_array *tr) +static void mmio_trace_start(struct trace_array *tr) { pr_debug("in %s\n", __func__); - if (tr->ctrl) { - mmio_reset_data(tr); - enable_mmiotrace(); - } else { - disable_mmiotrace(); - } + mmio_reset_data(tr); } static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev) @@ -298,10 +293,10 @@ static struct tracer mmio_tracer __read_mostly = .name = "mmiotrace", .init = mmio_trace_init, .reset = mmio_trace_reset, + .start = mmio_trace_start, .pipe_open = mmio_pipe_open, .close = mmio_close, .read = mmio_read, - .ctrl_update = mmio_trace_ctrl_update, .print_line = mmio_print_line, }; diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index 4592b48..e3c5fbf 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -42,21 +42,11 @@ static void nop_trace_reset(struct trace_array *tr) stop_nop_trace(tr); } -static void nop_trace_ctrl_update(struct trace_array *tr) -{ - /* When starting a new trace, reset the buffers */ - if (tr->ctrl) - start_nop_trace(tr); - else - stop_nop_trace(tr); -} - struct tracer nop_trace __read_mostly = { .name = "nop", .init = nop_trace_init, .reset = nop_trace_reset, - .ctrl_update = nop_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_nop, #endif diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 79410db..7b73fd1 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -220,15 +220,6 @@ static void sched_switch_trace_reset(struct trace_array *tr) stop_sched_trace(tr); } -static void sched_switch_trace_ctrl_update(struct trace_array *tr) -{ - /* When starting a new trace, reset the buffers */ - if (tr->ctrl) - start_sched_trace(tr); - else - stop_sched_trace(tr); -} - static void sched_switch_trace_start(struct trace_array *tr) { sched_switch_reset(tr); @@ -247,7 +238,6 @@ static struct tracer sched_switch_trace __read_mostly = .reset = sched_switch_trace_reset, .start = sched_switch_trace_start, .stop = sched_switch_trace_stop, - .ctrl_update = sched_switch_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_sched_switch, #endif diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 240577b..23e54d4 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -348,14 +348,6 @@ static void wakeup_tracer_reset(struct trace_array *tr) } } -static void wakeup_tracer_ctrl_update(struct trace_array *tr) -{ - if (tr->ctrl) - start_wakeup_tracer(tr); - else - stop_wakeup_tracer(tr); -} - static void wakeup_tracer_start(struct trace_array *tr) { wakeup_reset(tr); @@ -393,7 +385,6 @@ static struct tracer wakeup_tracer __read_mostly = .stop = wakeup_tracer_stop, .open = wakeup_tracer_open, .close = wakeup_tracer_close, - .ctrl_update = wakeup_tracer_ctrl_update, .print_max = 1, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_wakeup, diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 90bc752..7469343 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -134,13 +134,13 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, msleep(100); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); ftrace_enabled = 0; /* check the trace buffer */ ret = trace_test_buffer(tr, &count); trace->reset(tr); + tracing_start(); /* we should only have one item */ if (!ret && count != 1) { @@ -148,6 +148,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, ret = -1; goto out; } + out: ftrace_enabled = save_ftrace_enabled; tracer_enabled = save_tracer_enabled; @@ -185,13 +186,13 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); ftrace_enabled = 0; /* check the trace buffer */ ret = trace_test_buffer(tr, &count); trace->reset(tr); + tracing_start(); if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); @@ -232,13 +233,13 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) udelay(100); local_irq_enable(); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); if (!ret) ret = trace_test_buffer(&max_tr, &count); trace->reset(tr); + tracing_start(); if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); @@ -269,13 +270,13 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) udelay(100); preempt_enable(); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); if (!ret) ret = trace_test_buffer(&max_tr, &count); trace->reset(tr); + tracing_start(); if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); @@ -312,27 +313,30 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * local_irq_enable(); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); - if (ret) + if (ret) { + tracing_start(); goto out; + } ret = trace_test_buffer(&max_tr, &count); - if (ret) + if (ret) { + tracing_start(); goto out; + } if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); ret = -1; + tracing_start(); goto out; } /* do the test by disabling interrupts first this time */ tracing_max_latency = 0; - tr->ctrl = 1; - trace->ctrl_update(tr); + tracing_start(); preempt_disable(); local_irq_disable(); udelay(100); @@ -341,8 +345,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * local_irq_enable(); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); if (ret) @@ -358,6 +361,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * out: trace->reset(tr); + tracing_start(); tracing_max_latency = save_max; return ret; @@ -448,8 +452,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) msleep(100); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); if (!ret) @@ -457,6 +460,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) trace->reset(tr); + tracing_start(); tracing_max_latency = save_max; @@ -485,11 +489,11 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check the trace buffer */ ret = trace_test_buffer(tr, &count); trace->reset(tr); + tracing_start(); if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); @@ -513,11 +517,11 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr) /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ - tr->ctrl = 0; - trace->ctrl_update(tr); + tracing_stop(); /* check the trace buffer */ ret = trace_test_buffer(tr, &count); trace->reset(tr); + tracing_start(); return ret; } diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c index 9587d3b..8097430 100644 --- a/kernel/trace/trace_sysprof.c +++ b/kernel/trace/trace_sysprof.c @@ -275,21 +275,11 @@ static void stack_trace_reset(struct trace_array *tr) stop_stack_trace(tr); } -static void stack_trace_ctrl_update(struct trace_array *tr) -{ - /* When starting a new trace, reset the buffers */ - if (tr->ctrl) - start_stack_trace(tr); - else - stop_stack_trace(tr); -} - static struct tracer stack_trace __read_mostly = { .name = "sysprof", .init = stack_trace_init, .reset = stack_trace_reset, - .ctrl_update = stack_trace_ctrl_update, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_sysprof, #endif -- cgit v1.1 From c76f06945be50564f925799ddfb6235ee4c26aa0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: remove trace array ctrl Impact: remove obsolete variable in trace_array structure With the new start / stop method of ftrace, the ctrl variable in the trace_array structure is now obsolete. Remove it. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 20 +++++--------------- kernel/trace/trace.h | 1 - kernel/trace/trace_functions.c | 6 ++---- kernel/trace/trace_irqsoff.c | 7 ++----- kernel/trace/trace_mmiotrace.c | 11 +++++------ kernel/trace/trace_nop.c | 6 ++---- kernel/trace/trace_sched_switch.c | 6 ++---- kernel/trace/trace_sched_wakeup.c | 12 ++++-------- kernel/trace/trace_selftest.c | 8 -------- kernel/trace/trace_sysprof.c | 6 ++---- 10 files changed, 24 insertions(+), 59 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9e83188..5843541 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -537,7 +537,6 @@ int register_tracer(struct tracer *type) if (type->selftest) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; - int saved_ctrl = tr->ctrl; int i; /* * Run a selftest on this tracer. @@ -550,13 +549,11 @@ int register_tracer(struct tracer *type) tracing_reset(tr, i); } current_trace = type; - tr->ctrl = 0; /* the test is responsible for initializing and enabling */ pr_info("Testing tracer %s: ", type->name); ret = type->selftest(type, tr); /* the test is responsible for resetting too */ current_trace = saved_tracer; - tr->ctrl = saved_ctrl; if (ret) { printk(KERN_CONT "FAILED!\n"); goto out; @@ -966,7 +963,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) int cpu; int pc; - if (tracing_disabled || !tr->ctrl) + if (tracing_disabled) return; pc = preempt_count(); @@ -2820,7 +2817,6 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, unsigned long val; char buf[64]; int ret; - struct trace_array *tr = filp->private_data; if (cnt >= sizeof(buf)) return -EINVAL; @@ -2840,12 +2836,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, mutex_lock(&trace_types_lock); - if (tr->ctrl) { - cnt = -EBUSY; - pr_info("ftrace: please disable tracing" - " before modifying buffer size\n"); - goto out; - } + tracing_stop(); if (val != global_trace.entries) { ret = ring_buffer_resize(global_trace.buffer, val); @@ -2878,6 +2869,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, if (tracing_disabled) cnt = -ENOMEM; out: + tracing_start(); max_tr.entries = global_trace.entries; mutex_unlock(&trace_types_lock); @@ -2900,9 +2892,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, { char *buf; char *end; - struct trace_array *tr = &global_trace; - if (!tr->ctrl || tracing_disabled) + if (tracing_disabled) return -EINVAL; if (cnt > TRACE_BUF_SIZE) @@ -3131,7 +3122,7 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) unsigned long flags, irq_flags; int cpu, len = 0, size, pc; - if (!tr->ctrl || tracing_disabled) + if (tracing_disabled) return 0; pc = preempt_count(); @@ -3365,7 +3356,6 @@ __init static int tracer_alloc_buffers(void) #endif /* All seems OK, enable tracing */ - global_trace.ctrl = 1; tracing_disabled = 0; atomic_notifier_chain_register(&panic_notifier_list, diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index e481eda..cfda9d2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -172,7 +172,6 @@ struct trace_iterator; struct trace_array { struct ring_buffer *buffer; unsigned long entries; - long ctrl; int cpu; cycle_t time_start; struct task_struct *waiter; diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index e980b87..8693b7a 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -44,14 +44,12 @@ static void stop_function_trace(struct trace_array *tr) static void function_trace_init(struct trace_array *tr) { - if (tr->ctrl) - start_function_trace(tr); + start_function_trace(tr); } static void function_trace_reset(struct trace_array *tr) { - if (tr->ctrl) - stop_function_trace(tr); + stop_function_trace(tr); } static void function_trace_start(struct trace_array *tr) diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index ffdf592..d919d4e 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -383,15 +383,12 @@ static void __irqsoff_tracer_init(struct trace_array *tr) irqsoff_trace = tr; /* make sure that the tracer is visible */ smp_wmb(); - - if (tr->ctrl) - start_irqsoff_tracer(tr); + start_irqsoff_tracer(tr); } static void irqsoff_tracer_reset(struct trace_array *tr) { - if (tr->ctrl) - stop_irqsoff_tracer(tr); + stop_irqsoff_tracer(tr); } static void irqsoff_tracer_start(struct trace_array *tr) diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index fa9354e..51bcf37 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -34,17 +34,16 @@ static void mmio_trace_init(struct trace_array *tr) { pr_debug("in %s\n", __func__); mmio_trace_array = tr; - if (tr->ctrl) { - mmio_reset_data(tr); - enable_mmiotrace(); - } + + mmio_reset_data(tr); + enable_mmiotrace(); } static void mmio_trace_reset(struct trace_array *tr) { pr_debug("in %s\n", __func__); - if (tr->ctrl) - disable_mmiotrace(); + + disable_mmiotrace(); mmio_reset_data(tr); mmio_trace_array = NULL; } diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index e3c5fbf..2ef1d22 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -32,14 +32,12 @@ static void nop_trace_init(struct trace_array *tr) for_each_online_cpu(cpu) tracing_reset(tr, cpu); - if (tr->ctrl) - start_nop_trace(tr); + start_nop_trace(tr); } static void nop_trace_reset(struct trace_array *tr) { - if (tr->ctrl) - stop_nop_trace(tr); + stop_nop_trace(tr); } struct tracer nop_trace __read_mostly = diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 7b73fd1..be35bdf 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -209,14 +209,12 @@ static void stop_sched_trace(struct trace_array *tr) static void sched_switch_trace_init(struct trace_array *tr) { ctx_trace = tr; - - if (tr->ctrl) - start_sched_trace(tr); + start_sched_trace(tr); } static void sched_switch_trace_reset(struct trace_array *tr) { - if (tr->ctrl && sched_ref) + if (sched_ref) stop_sched_trace(tr); } diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 23e54d4..983f2b1 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -334,18 +334,14 @@ static void stop_wakeup_tracer(struct trace_array *tr) static void wakeup_tracer_init(struct trace_array *tr) { wakeup_trace = tr; - - if (tr->ctrl) - start_wakeup_tracer(tr); + start_wakeup_tracer(tr); } static void wakeup_tracer_reset(struct trace_array *tr) { - if (tr->ctrl) { - stop_wakeup_tracer(tr); - /* make sure we put back any tasks we are tracing */ - wakeup_reset(tr); - } + stop_wakeup_tracer(tr); + /* make sure we put back any tasks we are tracing */ + wakeup_reset(tr); } static void wakeup_tracer_start(struct trace_array *tr) diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 7469343..ea4e5d3 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -110,7 +110,6 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, ftrace_set_filter(func_name, strlen(func_name), 1); /* enable tracing */ - tr->ctrl = 1; trace->init(tr); /* Sleep for a 1/10 of a second */ @@ -181,7 +180,6 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) ftrace_enabled = 1; tracer_enabled = 1; - tr->ctrl = 1; trace->init(tr); /* Sleep for a 1/10 of a second */ msleep(100); @@ -224,7 +222,6 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* reset the max latency */ tracing_max_latency = 0; @@ -261,7 +258,6 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* reset the max latency */ tracing_max_latency = 0; @@ -298,7 +294,6 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * int ret; /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* reset the max latency */ @@ -427,7 +422,6 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) wait_for_completion(&isrt); /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* reset the max latency */ tracing_max_latency = 0; @@ -484,7 +478,6 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr int ret; /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* Sleep for a 1/10 of a second */ msleep(100); @@ -512,7 +505,6 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - tr->ctrl = 1; trace->init(tr); /* Sleep for a 1/10 of a second */ msleep(100); diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c index 8097430..05f7534 100644 --- a/kernel/trace/trace_sysprof.c +++ b/kernel/trace/trace_sysprof.c @@ -265,14 +265,12 @@ static void stack_trace_init(struct trace_array *tr) { sysprof_trace = tr; - if (tr->ctrl) - start_stack_trace(tr); + start_stack_trace(tr); } static void stack_trace_reset(struct trace_array *tr) { - if (tr->ctrl) - stop_stack_trace(tr); + stop_stack_trace(tr); } static struct tracer stack_trace __read_mostly = -- cgit v1.1 From 769c48eb2530c5c1a393e2c82063f4f050571d24 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: force pass of preemptoff selftest Impact: preemptoff not tested in selftest Due to the BKL not being preemptable anymore, the selftest of the preemptoff code can not be tested. It requires that it is called with preemption enabled, but since the BKL is held, that is no longer the case. This patch simply skips those tests if it detects that the context is not preemptable. The following will now show up in the tests: Testing tracer preemptoff: can not test ... force PASSED Testing tracer preemptirqsoff: can not test ... force PASSED When the BKL is removed, or it becomes preemptable once again, then the tests will be performed. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index ea4e5d3..0728a10 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -257,6 +257,19 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) unsigned long count; int ret; + /* + * Now that the big kernel lock is no longer preemptable, + * and this is called with the BKL held, it will always + * fail. If preemption is already disabled, simply + * pass the test. When the BKL is removed, or becomes + * preemptible again, we will once again test this, + * so keep it in. + */ + if (preempt_count()) { + printk(KERN_CONT "can not test ... force "); + return 0; + } + /* start the tracing */ trace->init(tr); /* reset the max latency */ @@ -293,6 +306,19 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * unsigned long count; int ret; + /* + * Now that the big kernel lock is no longer preemptable, + * and this is called with the BKL held, it will always + * fail. If preemption is already disabled, simply + * pass the test. When the BKL is removed, or becomes + * preemptible again, we will once again test this, + * so keep it in. + */ + if (preempt_count()) { + printk(KERN_CONT "can not test ... force "); + return 0; + } + /* start the tracing */ trace->init(tr); -- cgit v1.1 From a309720c876d7ad2e224bfd1982c92ae4364c82e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 7 Nov 2008 22:36:02 -0500 Subject: ftrace: display start of CPU buffer in trace output Impact: change in trace output Because the trace buffers are per cpu ring buffers, the start of the trace can be confusing. If one CPU is very active at the end of the trace, its history will not go as far back as the other CPU traces. This means that output for a particular CPU may not appear for the first part of a trace. To help annotate what is happening, and to prevent any more confusion, this patch adds a line that annotates the start of a CPU buffer output. For example: automount-3495 [001] 184.596443: dnotify_parent <-vfs_write [...] automount-3495 [001] 184.596449: dput <-path_put automount-3496 [002] 184.596450: down_read_trylock <-do_page_fault [...] sshd-3497 [001] 184.597069: up_read <-do_page_fault -0 [000] 184.597074: __exit_idle <-exit_idle [...] automount-3496 [002] 184.597257: filemap_fault <-__do_fault -0 [003] 184.597261: exit_idle <-smp_apic_timer_interrupt Note, parsers of a trace output should always ignore any lines that start with a '#'. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 19 +++++++++++++++++++ kernel/trace/trace.h | 2 ++ 2 files changed, 21 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5843541..f147f19 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1478,6 +1478,17 @@ void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter) trace_seq_putc(s, '\n'); } +static void test_cpu_buff_start(struct trace_iterator *iter) +{ + struct trace_seq *s = &iter->seq; + + if (cpu_isset(iter->cpu, iter->started)) + return; + + cpu_set(iter->cpu, iter->started); + trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu); +} + static enum print_line_t print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) { @@ -1497,6 +1508,8 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) if (entry->type == TRACE_CONT) return TRACE_TYPE_HANDLED; + test_cpu_buff_start(iter); + next_entry = find_next_entry(iter, NULL, &next_ts); if (!next_entry) next_ts = iter->ts; @@ -1612,6 +1625,8 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) if (entry->type == TRACE_CONT) return TRACE_TYPE_HANDLED; + test_cpu_buff_start(iter); + comm = trace_find_cmdline(iter->ent->pid); t = ns2usecs(iter->ts); @@ -2631,6 +2646,10 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) return -ENOMEM; mutex_lock(&trace_types_lock); + + /* trace pipe does not show start of buffer */ + cpus_setall(iter->started); + iter->tr = &global_trace; iter->trace = current_trace; filp->private_data = iter; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index cfda9d2..9781450 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -277,6 +277,8 @@ struct trace_iterator { unsigned long iter_flags; loff_t pos; long idx; + + cpumask_t started; }; int tracing_is_enabled(void); -- cgit v1.1 From 5aa1ba6a6c710e747838a22d798ac97a8b248745 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 10 Nov 2008 23:07:30 -0500 Subject: ftrace: prevent ftrace_special from recursion Impact: stop ftrace_special from recursion The ftrace_special is used to help debug areas of the kernel. Because of this, if it is put in certain locations, the fact that it allows recursion can become a problem if the kernel developer using does not realize that. This patch changes ftrace_special to not allow recursion into itself to make it more robust. It also changes from preempt disable interrupts disable to prevent any loss of trace entries. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0c22fe2..216bbe7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -960,6 +960,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { struct trace_array *tr = &global_trace; struct trace_array_cpu *data; + unsigned long flags; int cpu; int pc; @@ -967,14 +968,15 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) return; pc = preempt_count(); - preempt_disable_notrace(); + local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; - if (likely(!atomic_read(&data->disabled))) + if (likely(atomic_inc_return(&data->disabled) == 1)) ftrace_trace_special(tr, data, arg1, arg2, arg3, pc); - preempt_enable_notrace(); + atomic_dec(&data->disabled); + local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_TRACER -- cgit v1.1 From f536aafc5a2e6f0c8f1577a155e6f93db5e469f0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 10 Nov 2008 23:07:30 -0500 Subject: ring-buffer: replace most bug ons with warn on and disable buffer This patch replaces most of the BUG_ONs in the ring_buffer code with RB_WARN_ON variants. It adds some more variants as needed for the replacement. This lets the buffer die nicely and still warn the user. One BUG_ON remains in the code, and that is because it detects a bad pointer passed in by the calling function, and not a bug by the ring buffer code itself. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 65 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 49 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index ee9b93d..a6b8f9d 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -188,6 +188,7 @@ struct ring_buffer_iter { u64 read_stamp; }; +/* buffer may be either ring_buffer or ring_buffer_per_cpu */ #define RB_WARN_ON(buffer, cond) \ do { \ if (unlikely(cond)) { \ @@ -201,10 +202,28 @@ struct ring_buffer_iter { if (unlikely(cond)) { \ atomic_inc(&buffer->record_disabled); \ WARN_ON(1); \ + return; \ + } \ + } while (0) + +#define RB_WARN_ON_RET_INT(buffer, cond) \ + do { \ + if (unlikely(cond)) { \ + atomic_inc(&buffer->record_disabled); \ + WARN_ON(1); \ return -1; \ } \ } while (0) +#define RB_WARN_ON_RET_NULL(buffer, cond) \ + do { \ + if (unlikely(cond)) { \ + atomic_inc(&buffer->record_disabled); \ + WARN_ON(1); \ + return NULL; \ + } \ + } while (0) + #define RB_WARN_ON_ONCE(buffer, cond) \ do { \ static int once; \ @@ -215,6 +234,17 @@ struct ring_buffer_iter { } \ } while (0) +/* buffer must be ring_buffer not per_cpu */ +#define RB_WARN_ON_UNLOCK(buffer, cond) \ + do { \ + if (unlikely(cond)) { \ + mutex_unlock(&buffer->mutex); \ + atomic_inc(&buffer->record_disabled); \ + WARN_ON(1); \ + return -1; \ + } \ + } while (0) + /** * check_pages - integrity check of buffer pages * @cpu_buffer: CPU buffer with pages to test @@ -227,13 +257,13 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer) struct list_head *head = &cpu_buffer->pages; struct buffer_page *page, *tmp; - RB_WARN_ON_RET(cpu_buffer, head->next->prev != head); - RB_WARN_ON_RET(cpu_buffer, head->prev->next != head); + RB_WARN_ON_RET_INT(cpu_buffer, head->next->prev != head); + RB_WARN_ON_RET_INT(cpu_buffer, head->prev->next != head); list_for_each_entry_safe(page, tmp, head, list) { - RB_WARN_ON_RET(cpu_buffer, + RB_WARN_ON_RET_INT(cpu_buffer, page->list.next->prev != &page->list); - RB_WARN_ON_RET(cpu_buffer, + RB_WARN_ON_RET_INT(cpu_buffer, page->list.prev->next != &page->list); } @@ -440,13 +470,13 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) synchronize_sched(); for (i = 0; i < nr_pages; i++) { - BUG_ON(list_empty(&cpu_buffer->pages)); + RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages)); p = cpu_buffer->pages.next; page = list_entry(p, struct buffer_page, list); list_del_init(&page->list); free_buffer_page(page); } - BUG_ON(list_empty(&cpu_buffer->pages)); + RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages)); rb_reset_cpu(cpu_buffer); @@ -468,7 +498,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, synchronize_sched(); for (i = 0; i < nr_pages; i++) { - BUG_ON(list_empty(pages)); + RB_WARN_ON_RET(cpu_buffer, list_empty(pages)); p = pages->next; page = list_entry(p, struct buffer_page, list); list_del_init(&page->list); @@ -523,7 +553,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) if (size < buffer_size) { /* easy case, just free pages */ - BUG_ON(nr_pages >= buffer->pages); + RB_WARN_ON_UNLOCK(buffer, nr_pages >= buffer->pages); rm_pages = buffer->pages - nr_pages; @@ -542,7 +572,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) * add these pages to the cpu_buffers. Otherwise we just free * them all and return -ENOMEM; */ - BUG_ON(nr_pages <= buffer->pages); + RB_WARN_ON_UNLOCK(buffer, nr_pages <= buffer->pages); + new_pages = nr_pages - buffer->pages; for_each_buffer_cpu(buffer, cpu) { @@ -565,7 +596,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) rb_insert_pages(cpu_buffer, &pages, new_pages); } - BUG_ON(!list_empty(&pages)); + RB_WARN_ON_UNLOCK(buffer, !list_empty(&pages)); out: buffer->pages = nr_pages; @@ -653,7 +684,7 @@ static void rb_update_overflow(struct ring_buffer_per_cpu *cpu_buffer) head += rb_event_length(event)) { event = __rb_page_index(cpu_buffer->head_page, head); - BUG_ON(rb_null_event(event)); + RB_WARN_ON_RET(cpu_buffer, rb_null_event(event)); /* Only count data entries */ if (event->type != RINGBUF_TYPE_DATA) continue; @@ -940,7 +971,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* We reserved something on the buffer */ - BUG_ON(write > BUF_PAGE_SIZE); + RB_WARN_ON_RET_NULL(cpu_buffer, write > BUF_PAGE_SIZE); event = __rb_page_index(tail_page, tail); rb_update_event(event, type, length); @@ -1621,7 +1652,7 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer) reader = rb_get_reader_page(cpu_buffer); /* This function should not be called when buffer is empty */ - BUG_ON(!reader); + RB_WARN_ON_RET(cpu_buffer, !reader); event = rb_reader_event(cpu_buffer); @@ -1648,7 +1679,8 @@ static void rb_advance_iter(struct ring_buffer_iter *iter) * Check if we are at the end of the buffer. */ if (iter->head >= rb_page_size(iter->head_page)) { - BUG_ON(iter->head_page == cpu_buffer->commit_page); + RB_WARN_ON_RET(buffer, + iter->head_page == cpu_buffer->commit_page); rb_inc_iter(iter); return; } @@ -1661,8 +1693,9 @@ static void rb_advance_iter(struct ring_buffer_iter *iter) * This should not be called to advance the header if we are * at the tail of the buffer. */ - BUG_ON((iter->head_page == cpu_buffer->commit_page) && - (iter->head + length > rb_commit_index(cpu_buffer))); + RB_WARN_ON_RET(cpu_buffer, + (iter->head_page == cpu_buffer->commit_page) && + (iter->head + length > rb_commit_index(cpu_buffer))); rb_update_iter_read_stamp(iter, event); -- cgit v1.1 From caf4b323b02a16c92fba449952ac6515ddc76d7a Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 11 Nov 2008 07:03:45 +0100 Subject: tracing, x86: add low level support for ftrace return tracing Impact: add infrastructure for function-return tracing Add low level support for ftrace return tracing. This plug-in stores return addresses on the thread_info structure of the current task. The index of the current return address is initialized when the task is the first one (init) and when a process forks (the child). It is not needed when a task does a sys_execve because after this syscall, it still needs to return on the kernel functions it called. Note that the code of return_to_handler has been suggested by Steven Rostedt as almost all of the ideas of improvements in this V3. For purpose of security, arch/x86/kernel/process_32.c is not traced because __switch_to() changes the current task during its execution. That could cause inconsistency in the stored return address of this function even if I didn't have any crash after testing with tracing on this function enabled. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/Makefile | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 9a3ec66..af3be57 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -23,6 +23,10 @@ CFLAGS_REMOVE_cgroup-debug.o = -pg CFLAGS_REMOVE_sched_clock.o = -pg CFLAGS_REMOVE_sched.o = -mno-spe -pg endif +ifdef CONFIG_FUNCTION_RET_TRACER +CFLAGS_REMOVE_extable.o = -pg # For __kernel_text_address() +CFLAGS_REMOVE_module.o = -pg # For __module_text_address() +endif obj-$(CONFIG_FREEZER) += freezer.o obj-$(CONFIG_PROFILING) += profile.o -- cgit v1.1 From 15e6cb3673ea6277999642802406a764b49391b0 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 11 Nov 2008 07:14:25 +0100 Subject: tracing: add a tracer to catch execution time of kernel functions Impact: add new tracing plugin which can trace full (entry+exit) function calls This tracer uses the low level function return ftrace plugin to measure the execution time of the kernel functions. The first field is the caller of the function, the second is the measured function, and the last one is the execution time in nanoseconds. - v3: - HAVE_FUNCTION_RET_TRACER have been added. Each arch that support ftrace return should enable it. - ftrace_return_stub becomes ftrace_stub. - CONFIG_FUNCTION_RET_TRACER depends now on CONFIG_FUNCTION_TRACER - Return traces printing can be used for other tracers on trace.c - Adapt to the new tracing API (no more ctrl_update callback) - Correct the check of "disabled" during insertion. - Minor changes... Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 14 ++++++ kernel/trace/Makefile | 1 + kernel/trace/ftrace.c | 16 +++++++ kernel/trace/trace.c | 65 +++++++++++++++++++++++---- kernel/trace/trace.h | 35 +++++++++++++++ kernel/trace/trace_functions_return.c | 82 +++++++++++++++++++++++++++++++++++ 6 files changed, 205 insertions(+), 8 deletions(-) create mode 100644 kernel/trace/trace_functions_return.c (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index fc4febc..d986216 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -9,6 +9,9 @@ config NOP_TRACER config HAVE_FUNCTION_TRACER bool +config HAVE_FUNCTION_RET_TRACER + bool + config HAVE_FUNCTION_TRACE_MCOUNT_TEST bool help @@ -54,6 +57,17 @@ config FUNCTION_TRACER (the bootup default), then the overhead of the instructions is very small and not measurable even in micro-benchmarks. +config FUNCTION_RET_TRACER + bool "Kernel Function return Tracer" + depends on !DYNAMIC_FTRACE + depends on HAVE_FUNCTION_RET_TRACER + depends on FUNCTION_TRACER + help + Enable the kernel to trace a function at its return. + It's first purpose is to trace the duration of functions. + This is done by setting the current return address on the thread + info structure of the current task. + config IRQSOFF_TRACER bool "Interrupts-off Latency Tracer" default n diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index c8228b1..3e1f361 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -24,5 +24,6 @@ obj-$(CONFIG_NOP_TRACER) += trace_nop.o obj-$(CONFIG_STACK_TRACER) += trace_stack.o obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o +obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o libftrace-y := ftrace.o diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4d2e751..f03fe74 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1484,3 +1484,19 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, return ret; } +#ifdef CONFIG_FUNCTION_RET_TRACER +trace_function_return_t ftrace_function_return = + (trace_function_return_t)ftrace_stub; +void register_ftrace_return(trace_function_return_t func) +{ + ftrace_function_return = func; +} + +void unregister_ftrace_return(void) +{ + ftrace_function_return = (trace_function_return_t)ftrace_stub; +} +#endif + + + diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 216bbe7..a3f7ae9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -244,13 +244,6 @@ unsigned long nsecs_to_usecs(unsigned long nsecs) return nsecs / 1000; } -/* - * TRACE_ITER_SYM_MASK masks the options in trace_flags that - * control the output of kernel symbols. - */ -#define TRACE_ITER_SYM_MASK \ - (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR) - /* These must match the bit postions in trace_iterator_flags */ static const char *trace_options[] = { "print-parent", @@ -810,6 +803,35 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data, ring_buffer_unlock_commit(tr->buffer, event, irq_flags); } +#ifdef CONFIG_FUNCTION_RET_TRACER +static void __trace_function_return(struct trace_array *tr, + struct trace_array_cpu *data, + struct ftrace_retfunc *trace, + unsigned long flags, + int pc) +{ + struct ring_buffer_event *event; + struct ftrace_ret_entry *entry; + unsigned long irq_flags; + + if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) + return; + + event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry), + &irq_flags); + if (!event) + return; + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, flags, pc); + entry->ent.type = TRACE_FN_RET; + entry->ip = trace->func; + entry->parent_ip = trace->ret; + entry->rettime = trace->rettime; + entry->calltime = trace->calltime; + ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags); +} +#endif + void ftrace(struct trace_array *tr, struct trace_array_cpu *data, unsigned long ip, unsigned long parent_ip, unsigned long flags, @@ -1038,6 +1060,29 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) raw_local_irq_restore(flags); } +#ifdef CONFIG_FUNCTION_RET_TRACER +void trace_function_return(struct ftrace_retfunc *trace) +{ + struct trace_array *tr = &global_trace; + struct trace_array_cpu *data; + unsigned long flags; + long disabled; + int cpu; + int pc; + + raw_local_irq_save(flags); + cpu = raw_smp_processor_id(); + data = tr->data[cpu]; + disabled = atomic_inc_return(&data->disabled); + if (likely(disabled == 1)) { + pc = preempt_count(); + __trace_function_return(tr, data, trace, flags, pc); + } + atomic_dec(&data->disabled); + raw_local_irq_restore(flags); +} +#endif /* CONFIG_FUNCTION_RET_TRACER */ + static struct ftrace_ops trace_ops __read_mostly = { .func = function_trace_call, @@ -1285,7 +1330,7 @@ seq_print_sym_offset(struct trace_seq *s, const char *fmt, # define IP_FMT "%016lx" #endif -static int +int seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags) { int ret; @@ -1738,6 +1783,10 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) trace_seq_print_cont(s, iter); break; } + case TRACE_FN_RET: { + return print_return_function(iter); + break; + } } return TRACE_TYPE_HANDLED; } diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9781450..e40ce0c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -22,6 +22,7 @@ enum trace_type { TRACE_MMIO_RW, TRACE_MMIO_MAP, TRACE_BOOT, + TRACE_FN_RET, __TRACE_LAST_TYPE }; @@ -48,6 +49,15 @@ struct ftrace_entry { unsigned long ip; unsigned long parent_ip; }; + +/* Function return entry */ +struct ftrace_ret_entry { + struct trace_entry ent; + unsigned long ip; + unsigned long parent_ip; + unsigned long long calltime; + unsigned long long rettime; +}; extern struct tracer boot_tracer; /* @@ -218,6 +228,7 @@ extern void __ftrace_bad_type(void); IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \ TRACE_MMIO_MAP); \ IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \ + IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET); \ __ftrace_bad_type(); \ } while (0) @@ -321,6 +332,8 @@ void trace_function(struct trace_array *tr, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc); +void +trace_function_return(struct ftrace_retfunc *trace); void tracing_start_cmdline_record(void); void tracing_stop_cmdline_record(void); @@ -393,6 +406,10 @@ extern void *head_page(struct trace_array_cpu *data); extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...); extern void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter); + +extern int +seq_print_ip_sym(struct trace_seq *s, unsigned long ip, + unsigned long sym_flags); extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt); extern long ns2usecs(cycle_t nsec); @@ -400,6 +417,17 @@ extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args); extern unsigned long trace_flags; +/* Standard output formatting function used for function return traces */ +#ifdef CONFIG_FUNCTION_RET_TRACER +extern enum print_line_t print_return_function(struct trace_iterator *iter); +#else +static inline enum print_line_t +print_return_function(struct trace_iterator *iter) +{ + return TRACE_TYPE_UNHANDLED; +} +#endif + /* * trace_iterator_flags is an enumeration that defines bit * positions into trace_flags that controls the output. @@ -422,6 +450,13 @@ enum trace_iterator_flags { TRACE_ITER_PREEMPTONLY = 0x800, }; +/* + * TRACE_ITER_SYM_MASK masks the options in trace_flags that + * control the output of kernel symbols. + */ +#define TRACE_ITER_SYM_MASK \ + (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR) + extern struct tracer nop_trace; /** diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c new file mode 100644 index 0000000..7680b21 --- /dev/null +++ b/kernel/trace/trace_functions_return.c @@ -0,0 +1,82 @@ +/* + * + * Function return tracer. + * Copyright (c) 2008 Frederic Weisbecker + * Mostly borrowed from function tracer which + * is Copyright (c) Steven Rostedt + * + */ +#include +#include +#include +#include + +#include "trace.h" + + +static void start_return_trace(struct trace_array *tr) +{ + register_ftrace_return(&trace_function_return); +} + +static void stop_return_trace(struct trace_array *tr) +{ + unregister_ftrace_return(); +} + +static void return_trace_init(struct trace_array *tr) +{ + int cpu; + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); + + start_return_trace(tr); +} + +static void return_trace_reset(struct trace_array *tr) +{ + stop_return_trace(tr); +} + + +enum print_line_t +print_return_function(struct trace_iterator *iter) +{ + struct trace_seq *s = &iter->seq; + struct trace_entry *entry = iter->ent; + struct ftrace_ret_entry *field; + int ret; + + if (entry->type == TRACE_FN_RET) { + trace_assign_type(field, entry); + ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + ret = seq_print_ip_sym(s, field->ip, + trace_flags & TRACE_ITER_SYM_MASK); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + ret = trace_seq_printf(s, " (%llu ns)\n", + field->rettime - field->calltime); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + else + return TRACE_TYPE_HANDLED; + } + return TRACE_TYPE_UNHANDLED; +} + +static struct tracer return_trace __read_mostly = +{ + .name = "return", + .init = return_trace_init, + .reset = return_trace_reset, + .print_line = print_return_function +}; + +static __init int init_return_trace(void) +{ + return register_tracer(&return_trace); +} + +device_initcall(init_return_trace); -- cgit v1.1 From f83c9d0fe42a7544b4d4ffcebb2e6716fcfd95c0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 11 Nov 2008 18:47:44 +0100 Subject: ring-buffer: add reader lock Impact: serialize reader accesses to individual CPU ring buffers The code in the ring buffer expects only one reader at a time, but currently it puts that requirement on the caller. This is not strong enough, and this patch adds a "reader_lock" that serializes the access to the reader API of the ring buffer. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 109 ++++++++++++++++++++++++++++++++------------- 1 file changed, 78 insertions(+), 31 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a6b8f9d..17c2cce 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -154,6 +154,7 @@ static inline int test_time_stamp(u64 delta) struct ring_buffer_per_cpu { int cpu; struct ring_buffer *buffer; + spinlock_t reader_lock; /* serialize readers */ raw_spinlock_t lock; struct lock_class_key lock_key; struct list_head pages; @@ -321,6 +322,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu) cpu_buffer->cpu = cpu; cpu_buffer->buffer = buffer; + spin_lock_init(&cpu_buffer->reader_lock); cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; INIT_LIST_HEAD(&cpu_buffer->pages); @@ -1476,6 +1478,9 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer) void ring_buffer_iter_reset(struct ring_buffer_iter *iter) { struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; + unsigned long flags; + + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); /* Iterator usage is expected to have record disabled */ if (list_empty(&cpu_buffer->reader_page->list)) { @@ -1489,6 +1494,8 @@ void ring_buffer_iter_reset(struct ring_buffer_iter *iter) iter->read_stamp = cpu_buffer->read_stamp; else iter->read_stamp = iter->head_page->time_stamp; + + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); } /** @@ -1707,17 +1714,8 @@ static void rb_advance_iter(struct ring_buffer_iter *iter) rb_advance_iter(iter); } -/** - * ring_buffer_peek - peek at the next event to be read - * @buffer: The ring buffer to read - * @cpu: The cpu to peak at - * @ts: The timestamp counter of this event. - * - * This will return the event that will be read next, but does - * not consume the data. - */ -struct ring_buffer_event * -ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) +static struct ring_buffer_event * +rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) { struct ring_buffer_per_cpu *cpu_buffer; struct ring_buffer_event *event; @@ -1779,16 +1777,8 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) return NULL; } -/** - * ring_buffer_iter_peek - peek at the next event to be read - * @iter: The ring buffer iterator - * @ts: The timestamp counter of this event. - * - * This will return the event that will be read next, but does - * not increment the iterator. - */ -struct ring_buffer_event * -ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts) +static struct ring_buffer_event * +rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) { struct ring_buffer *buffer; struct ring_buffer_per_cpu *cpu_buffer; @@ -1850,6 +1840,51 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts) } /** + * ring_buffer_peek - peek at the next event to be read + * @buffer: The ring buffer to read + * @cpu: The cpu to peak at + * @ts: The timestamp counter of this event. + * + * This will return the event that will be read next, but does + * not consume the data. + */ +struct ring_buffer_event * +ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) +{ + struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; + struct ring_buffer_event *event; + unsigned long flags; + + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + event = rb_buffer_peek(buffer, cpu, ts); + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + + return event; +} + +/** + * ring_buffer_iter_peek - peek at the next event to be read + * @iter: The ring buffer iterator + * @ts: The timestamp counter of this event. + * + * This will return the event that will be read next, but does + * not increment the iterator. + */ +struct ring_buffer_event * +ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts) +{ + struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; + struct ring_buffer_event *event; + unsigned long flags; + + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + event = rb_iter_peek(iter, ts); + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + + return event; +} + +/** * ring_buffer_consume - return an event and consume it * @buffer: The ring buffer to get the next event from * @@ -1860,19 +1895,24 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_event * ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts) { - struct ring_buffer_per_cpu *cpu_buffer; + struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; struct ring_buffer_event *event; + unsigned long flags; if (!cpu_isset(cpu, buffer->cpumask)) return NULL; - event = ring_buffer_peek(buffer, cpu, ts); + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + + event = rb_buffer_peek(buffer, cpu, ts); if (!event) - return NULL; + goto out; - cpu_buffer = buffer->buffers[cpu]; rb_advance_reader(cpu_buffer); + out: + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + return event; } @@ -1909,11 +1949,11 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu) atomic_inc(&cpu_buffer->record_disabled); synchronize_sched(); - local_irq_save(flags); + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); __raw_spin_lock(&cpu_buffer->lock); ring_buffer_iter_reset(iter); __raw_spin_unlock(&cpu_buffer->lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); return iter; } @@ -1945,12 +1985,17 @@ struct ring_buffer_event * ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts) { struct ring_buffer_event *event; + struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; + unsigned long flags; - event = ring_buffer_iter_peek(iter, ts); + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + event = rb_iter_peek(iter, ts); if (!event) - return NULL; + goto out; rb_advance_iter(iter); + out: + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); return event; } @@ -1999,13 +2044,15 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu) if (!cpu_isset(cpu, buffer->cpumask)) return; - local_irq_save(flags); + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + __raw_spin_lock(&cpu_buffer->lock); rb_reset_cpu(cpu_buffer); __raw_spin_unlock(&cpu_buffer->lock); - local_irq_restore(flags); + + spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); } /** -- cgit v1.1 From 3e89c7bb92fc92bb964734341487798c8d497bae Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 11 Nov 2008 15:28:41 -0500 Subject: ring-buffer: clean up warn ons Impact: Restructure WARN_ONs in ring_buffer.c The current WARN_ON macros in ring_buffer.c are quite ugly. This patch cleans them up and uses a single RB_WARN_ON that returns the value of the condition. This allows the caller to abort the function if the condition is true. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 143 ++++++++++++++++++--------------------------- 1 file changed, 57 insertions(+), 86 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 17c2cce..8c5cacb 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -191,60 +191,14 @@ struct ring_buffer_iter { /* buffer may be either ring_buffer or ring_buffer_per_cpu */ #define RB_WARN_ON(buffer, cond) \ - do { \ - if (unlikely(cond)) { \ + ({ \ + int _____ret = unlikely(cond); \ + if (_____ret) { \ atomic_inc(&buffer->record_disabled); \ WARN_ON(1); \ } \ - } while (0) - -#define RB_WARN_ON_RET(buffer, cond) \ - do { \ - if (unlikely(cond)) { \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - return; \ - } \ - } while (0) - -#define RB_WARN_ON_RET_INT(buffer, cond) \ - do { \ - if (unlikely(cond)) { \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - return -1; \ - } \ - } while (0) - -#define RB_WARN_ON_RET_NULL(buffer, cond) \ - do { \ - if (unlikely(cond)) { \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - return NULL; \ - } \ - } while (0) - -#define RB_WARN_ON_ONCE(buffer, cond) \ - do { \ - static int once; \ - if (unlikely(cond) && !once) { \ - once++; \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - } \ - } while (0) - -/* buffer must be ring_buffer not per_cpu */ -#define RB_WARN_ON_UNLOCK(buffer, cond) \ - do { \ - if (unlikely(cond)) { \ - mutex_unlock(&buffer->mutex); \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - return -1; \ - } \ - } while (0) + _____ret; \ + }) /** * check_pages - integrity check of buffer pages @@ -258,14 +212,18 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer) struct list_head *head = &cpu_buffer->pages; struct buffer_page *page, *tmp; - RB_WARN_ON_RET_INT(cpu_buffer, head->next->prev != head); - RB_WARN_ON_RET_INT(cpu_buffer, head->prev->next != head); + if (RB_WARN_ON(cpu_buffer, head->next->prev != head)) + return -1; + if (RB_WARN_ON(cpu_buffer, head->prev->next != head)) + return -1; list_for_each_entry_safe(page, tmp, head, list) { - RB_WARN_ON_RET_INT(cpu_buffer, - page->list.next->prev != &page->list); - RB_WARN_ON_RET_INT(cpu_buffer, - page->list.prev->next != &page->list); + if (RB_WARN_ON(cpu_buffer, + page->list.next->prev != &page->list)) + return -1; + if (RB_WARN_ON(cpu_buffer, + page->list.prev->next != &page->list)) + return -1; } return 0; @@ -472,13 +430,15 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) synchronize_sched(); for (i = 0; i < nr_pages; i++) { - RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages)); + if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages))) + return; p = cpu_buffer->pages.next; page = list_entry(p, struct buffer_page, list); list_del_init(&page->list); free_buffer_page(page); } - RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages)); + if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages))) + return; rb_reset_cpu(cpu_buffer); @@ -500,7 +460,8 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, synchronize_sched(); for (i = 0; i < nr_pages; i++) { - RB_WARN_ON_RET(cpu_buffer, list_empty(pages)); + if (RB_WARN_ON(cpu_buffer, list_empty(pages))) + return; p = pages->next; page = list_entry(p, struct buffer_page, list); list_del_init(&page->list); @@ -555,7 +516,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) if (size < buffer_size) { /* easy case, just free pages */ - RB_WARN_ON_UNLOCK(buffer, nr_pages >= buffer->pages); + if (RB_WARN_ON(buffer, nr_pages >= buffer->pages)) { + mutex_unlock(&buffer->mutex); + return -1; + } rm_pages = buffer->pages - nr_pages; @@ -574,7 +538,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) * add these pages to the cpu_buffers. Otherwise we just free * them all and return -ENOMEM; */ - RB_WARN_ON_UNLOCK(buffer, nr_pages <= buffer->pages); + if (RB_WARN_ON(buffer, nr_pages <= buffer->pages)) { + mutex_unlock(&buffer->mutex); + return -1; + } new_pages = nr_pages - buffer->pages; @@ -598,7 +565,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) rb_insert_pages(cpu_buffer, &pages, new_pages); } - RB_WARN_ON_UNLOCK(buffer, !list_empty(&pages)); + if (RB_WARN_ON(buffer, !list_empty(&pages))) { + mutex_unlock(&buffer->mutex); + return -1; + } out: buffer->pages = nr_pages; @@ -686,7 +656,8 @@ static void rb_update_overflow(struct ring_buffer_per_cpu *cpu_buffer) head += rb_event_length(event)) { event = __rb_page_index(cpu_buffer->head_page, head); - RB_WARN_ON_RET(cpu_buffer, rb_null_event(event)); + if (RB_WARN_ON(cpu_buffer, rb_null_event(event))) + return; /* Only count data entries */ if (event->type != RINGBUF_TYPE_DATA) continue; @@ -739,8 +710,9 @@ rb_set_commit_event(struct ring_buffer_per_cpu *cpu_buffer, addr &= PAGE_MASK; while (cpu_buffer->commit_page->page != (void *)addr) { - RB_WARN_ON(cpu_buffer, - cpu_buffer->commit_page == cpu_buffer->tail_page); + if (RB_WARN_ON(cpu_buffer, + cpu_buffer->commit_page == cpu_buffer->tail_page)) + return; cpu_buffer->commit_page->commit = cpu_buffer->commit_page->write; rb_inc_page(cpu_buffer, &cpu_buffer->commit_page); @@ -896,7 +868,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, reader_page = cpu_buffer->reader_page; /* we grabbed the lock before incrementing */ - RB_WARN_ON(cpu_buffer, next_page == reader_page); + if (RB_WARN_ON(cpu_buffer, next_page == reader_page)) + goto out_unlock; /* * If for some reason, we had an interrupt storm that made @@ -973,7 +946,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* We reserved something on the buffer */ - RB_WARN_ON_RET_NULL(cpu_buffer, write > BUF_PAGE_SIZE); + if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE)) + return NULL; event = __rb_page_index(tail_page, tail); rb_update_event(event, type, length); @@ -1072,10 +1046,8 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer, * storm or we have something buggy. * Bail! */ - if (unlikely(++nr_loops > 1000)) { - RB_WARN_ON(cpu_buffer, 1); + if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000)) return NULL; - } ts = ring_buffer_time_stamp(cpu_buffer->cpu); @@ -1591,8 +1563,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) * a case where we will loop three times. There should be no * reason to loop four times (that I know of). */ - if (unlikely(++nr_loops > 3)) { - RB_WARN_ON(cpu_buffer, 1); + if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) { reader = NULL; goto out; } @@ -1604,8 +1575,9 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) goto out; /* Never should we have an index greater than the size */ - RB_WARN_ON(cpu_buffer, - cpu_buffer->reader_page->read > rb_page_size(reader)); + if (RB_WARN_ON(cpu_buffer, + cpu_buffer->reader_page->read > rb_page_size(reader))) + goto out; /* check if we caught up to the tail */ reader = NULL; @@ -1659,7 +1631,8 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer) reader = rb_get_reader_page(cpu_buffer); /* This function should not be called when buffer is empty */ - RB_WARN_ON_RET(cpu_buffer, !reader); + if (RB_WARN_ON(cpu_buffer, !reader)) + return; event = rb_reader_event(cpu_buffer); @@ -1686,8 +1659,9 @@ static void rb_advance_iter(struct ring_buffer_iter *iter) * Check if we are at the end of the buffer. */ if (iter->head >= rb_page_size(iter->head_page)) { - RB_WARN_ON_RET(buffer, - iter->head_page == cpu_buffer->commit_page); + if (RB_WARN_ON(buffer, + iter->head_page == cpu_buffer->commit_page)) + return; rb_inc_iter(iter); return; } @@ -1700,9 +1674,10 @@ static void rb_advance_iter(struct ring_buffer_iter *iter) * This should not be called to advance the header if we are * at the tail of the buffer. */ - RB_WARN_ON_RET(cpu_buffer, + if (RB_WARN_ON(cpu_buffer, (iter->head_page == cpu_buffer->commit_page) && - (iter->head + length > rb_commit_index(cpu_buffer))); + (iter->head + length > rb_commit_index(cpu_buffer)))) + return; rb_update_iter_read_stamp(iter, event); @@ -1736,10 +1711,8 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) * can have. Nesting 10 deep of interrupts is clearly * an anomaly. */ - if (unlikely(++nr_loops > 10)) { - RB_WARN_ON(cpu_buffer, 1); + if (RB_WARN_ON(cpu_buffer, ++nr_loops > 10)) return NULL; - } reader = rb_get_reader_page(cpu_buffer); if (!reader) @@ -1800,10 +1773,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) * can have. Nesting 10 deep of interrupts is clearly * an anomaly. */ - if (unlikely(++nr_loops > 10)) { - RB_WARN_ON(cpu_buffer, 1); + if (RB_WARN_ON(cpu_buffer, ++nr_loops > 10)) return NULL; - } if (rb_per_cpu_empty(cpu_buffer)) return NULL; -- cgit v1.1 From 3f5ec13696fd4a33bde42f385406cbb1d3cc96fd Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 11 Nov 2008 23:21:31 +0100 Subject: tracing/fastboot: move boot tracer structs and funcs into their own header. Impact: Cleanups on the boot tracer and ftrace This patch bring some cleanups about the boot tracer headers. The functions and structures of this tracer have nothing related to ftrace and should have so their own header file. Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index e40ce0c..f69a519 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -8,6 +8,7 @@ #include #include #include +#include enum trace_type { __TRACE_FIRST_TYPE = 0, -- cgit v1.1 From 74239072830ef3f1398edeb1bc1076fc330fd4a2 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 11 Nov 2008 23:24:42 +0100 Subject: tracing/fastboot: Use the ring-buffer timestamp for initcall entries Impact: Split the boot tracer entries in two parts: call and return Now that we are using the sched tracer from the boot tracer, we want to use the same timestamp than the ring-buffer to have consistent time captures between sched events and initcall events. So we get rid of the old time capture by the boot tracer and split the initcall events in two parts: call and return. This way we have the ring buffer timestamp of both. An example trace: [ 27.904149584] calling net_ns_init+0x0/0x1c0 @ 1 [ 27.904429624] initcall net_ns_init+0x0/0x1c0 returned 0 after 0 msecs [ 27.904575926] calling reboot_init+0x0/0x20 @ 1 [ 27.904655399] initcall reboot_init+0x0/0x20 returned 0 after 0 msecs [ 27.904800228] calling sysctl_init+0x0/0x30 @ 1 [ 27.905142914] initcall sysctl_init+0x0/0x30 returned 0 after 0 msecs [ 27.905287211] calling ksysfs_init+0x0/0xb0 @ 1 ##### CPU 0 buffer started #### init-1 [000] 27.905395: 1:120:R + [001] 11:115:S ##### CPU 1 buffer started #### -0 [001] 27.905425: 0:140:R ==> [001] 11:115:R init-1 [000] 27.905426: 1:120:D ==> [000] 0:140:R -0 [000] 27.905431: 0:140:R + [000] 4:115:S -0 [000] 27.905451: 0:140:R ==> [000] 4:115:R ksoftirqd/0-4 [000] 27.905456: 4:115:S ==> [000] 0:140:R udevd-11 [001] 27.905458: 11:115:R + [001] 14:115:R -0 [000] 27.905459: 0:140:R + [000] 4:115:S -0 [000] 27.905462: 0:140:R ==> [000] 4:115:R udevd-11 [001] 27.905462: 11:115:R ==> [001] 14:115:R ksoftirqd/0-4 [000] 27.905467: 4:115:S ==> [000] 0:140:R -0 [000] 27.905470: 0:140:R + [000] 4:115:S -0 [000] 27.905473: 0:140:R ==> [000] 4:115:R ksoftirqd/0-4 [000] 27.905476: 4:115:S ==> [000] 0:140:R -0 [000] 27.905479: 0:140:R + [000] 4:115:S -0 [000] 27.905482: 0:140:R ==> [000] 4:115:R ksoftirqd/0-4 [000] 27.905486: 4:115:S ==> [000] 0:140:R udevd-14 [001] 27.905499: 14:120:X ==> [001] 11:115:R udevd-11 [001] 27.905506: 11:115:R + [000] 1:120:D -0 [000] 27.905515: 0:140:R ==> [000] 1:120:R udevd-11 [001] 27.905517: 11:115:S ==> [001] 0:140:R [ 27.905557107] initcall ksysfs_init+0x0/0xb0 returned 0 after 3906 msecs [ 27.905705736] calling init_jiffies_clocksource+0x0/0x10 @ 1 [ 27.905779239] initcall init_jiffies_clocksource+0x0/0x10 returned 0 after 0 msecs [ 27.906769814] calling pm_init+0x0/0x30 @ 1 [ 27.906853627] initcall pm_init+0x0/0x30 returned 0 after 0 msecs [ 27.906997803] calling pm_disk_init+0x0/0x20 @ 1 [ 27.907076946] initcall pm_disk_init+0x0/0x20 returned 0 after 0 msecs [ 27.907222556] calling swsusp_header_init+0x0/0x30 @ 1 [ 27.907294325] initcall swsusp_header_init+0x0/0x30 returned 0 after 0 msecs [ 27.907439620] calling stop_machine_init+0x0/0x50 @ 1 init-1 [000] 27.907485: 1:120:R + [000] 2:115:S init-1 [000] 27.907490: 1:120:D ==> [000] 2:115:R kthreadd-2 [000] 27.907507: 2:115:R + [001] 15:115:R -0 [001] 27.907517: 0:140:R ==> [001] 15:115:R kthreadd-2 [000] 27.907517: 2:115:D ==> [000] 0:140:R -0 [000] 27.907521: 0:140:R + [000] 4:115:S -0 [000] 27.907524: 0:140:R ==> [000] 4:115:R udevd-15 [001] 27.907527: 15:115:D + [000] 2:115:D ksoftirqd/0-4 [000] 27.907537: 4:115:S ==> [000] 2:115:R udevd-15 [001] 27.907537: 15:115:D ==> [001] 0:140:R kthreadd-2 [000] 27.907546: 2:115:R + [000] 1:120:D kthreadd-2 [000] 27.907550: 2:115:S ==> [000] 1:120:R init-1 [000] 27.907584: 1:120:R + [000] 15: 0:D init-1 [000] 27.907589: 1:120:R + [000] 2:115:S init-1 [000] 27.907593: 1:120:D ==> [000] 15: 0:R udevd-15 [000] 27.907601: 15: 0:S ==> [000] 2:115:R ##### CPU 0 buffer started #### kthreadd-2 [000] 27.907616: 2:115:R + [001] 16:115:R ##### CPU 1 buffer started #### -0 [001] 27.907620: 0:140:R ==> [001] 16:115:R kthreadd-2 [000] 27.907621: 2:115:D ==> [000] 0:140:R udevd-16 [001] 27.907625: 16:115:D + [000] 2:115:D -0 [000] 27.907628: 0:140:R + [000] 4:115:S udevd-16 [001] 27.907629: 16:115:D ==> [001] 0:140:R -0 [000] 27.907631: 0:140:R ==> [000] 4:115:R ksoftirqd/0-4 [000] 27.907636: 4:115:S ==> [000] 2:115:R kthreadd-2 [000] 27.907644: 2:115:R + [000] 1:120:D kthreadd-2 [000] 27.907647: 2:115:S ==> [000] 1:120:R init-1 [000] 27.907657: 1:120:R + [001] 16: 0:D -0 [001] 27.907666: 0:140:R ==> [001] 16: 0:R [ 27.907703862] initcall stop_machine_init+0x0/0x50 returned 0 after 0 msecs [ 27.907850704] calling filelock_init+0x0/0x30 @ 1 [ 27.907926573] initcall filelock_init+0x0/0x30 returned 0 after 0 msecs [ 27.908071327] calling init_script_binfmt+0x0/0x10 @ 1 [ 27.908165195] initcall init_script_binfmt+0x0/0x10 returned 0 after 0 msecs [ 27.908309461] calling init_elf_binfmt+0x0/0x10 @ 1 Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 17 +++++-- kernel/trace/trace_boot.c | 123 +++++++++++++++++++++++++++++++++++----------- 2 files changed, 105 insertions(+), 35 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f69a519..b5f91f1 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -22,7 +22,8 @@ enum trace_type { TRACE_SPECIAL, TRACE_MMIO_RW, TRACE_MMIO_MAP, - TRACE_BOOT, + TRACE_BOOT_CALL, + TRACE_BOOT_RET, TRACE_FN_RET, __TRACE_LAST_TYPE @@ -123,9 +124,14 @@ struct trace_mmiotrace_map { struct mmiotrace_map map; }; -struct trace_boot { +struct trace_boot_call { struct trace_entry ent; - struct boot_trace initcall; + struct boot_trace_call boot_call; +}; + +struct trace_boot_ret { + struct trace_entry ent; + struct boot_trace_ret boot_ret; }; /* @@ -228,8 +234,9 @@ extern void __ftrace_bad_type(void); TRACE_MMIO_RW); \ IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \ TRACE_MMIO_MAP); \ - IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \ - IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET); \ + IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\ + IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\ + IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET);\ __ftrace_bad_type(); \ } while (0) diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 8f71915..cb333b7 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -58,35 +58,71 @@ static void boot_trace_init(struct trace_array *tr) tracing_sched_switch_assign_trace(tr); } -static enum print_line_t initcall_print_line(struct trace_iterator *iter) +static enum print_line_t +initcall_call_print_line(struct trace_iterator *iter) { + struct trace_entry *entry = iter->ent; + struct trace_seq *s = &iter->seq; + struct trace_boot_call *field; + struct boot_trace_call *call; + u64 ts; + unsigned long nsec_rem; int ret; + + trace_assign_type(field, entry); + call = &field->boot_call; + ts = iter->ts; + nsec_rem = do_div(ts, 1000000000); + + ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n", + (unsigned long)ts, nsec_rem, call->func, call->caller); + + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + else + return TRACE_TYPE_HANDLED; +} + +static enum print_line_t +initcall_ret_print_line(struct trace_iterator *iter) +{ struct trace_entry *entry = iter->ent; - struct trace_boot *field = (struct trace_boot *)entry; - struct boot_trace *it = &field->initcall; struct trace_seq *s = &iter->seq; - struct timespec calltime = ktime_to_timespec(it->calltime); - struct timespec rettime = ktime_to_timespec(it->rettime); - - if (entry->type == TRACE_BOOT) { - ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n", - calltime.tv_sec, - calltime.tv_nsec, - it->func, it->caller); - if (!ret) - return TRACE_TYPE_PARTIAL_LINE; - - ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s " - "returned %d after %lld msecs\n", - rettime.tv_sec, - rettime.tv_nsec, - it->func, it->result, it->duration); - - if (!ret) - return TRACE_TYPE_PARTIAL_LINE; + struct trace_boot_ret *field; + struct boot_trace_ret *init_ret; + u64 ts; + unsigned long nsec_rem; + int ret; + + trace_assign_type(field, entry); + init_ret = &field->boot_ret; + ts = iter->ts; + nsec_rem = do_div(ts, 1000000000); + + ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s " + "returned %d after %llu msecs\n", + (unsigned long) ts, + nsec_rem, + init_ret->func, init_ret->result, init_ret->duration); + + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + else return TRACE_TYPE_HANDLED; +} + +static enum print_line_t initcall_print_line(struct trace_iterator *iter) +{ + struct trace_entry *entry = iter->ent; + + switch (entry->type) { + case TRACE_BOOT_CALL: + return initcall_call_print_line(iter); + case TRACE_BOOT_RET: + return initcall_ret_print_line(iter); + default: + return TRACE_TYPE_UNHANDLED; } - return TRACE_TYPE_UNHANDLED; } struct tracer boot_tracer __read_mostly = @@ -97,11 +133,10 @@ struct tracer boot_tracer __read_mostly = .print_line = initcall_print_line, }; -void trace_boot(struct boot_trace *it, initcall_t fn) +void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) { struct ring_buffer_event *event; - struct trace_boot *entry; - struct trace_array_cpu *data; + struct trace_boot_call *entry; unsigned long irq_flags; struct trace_array *tr = boot_trace; @@ -111,9 +146,37 @@ void trace_boot(struct boot_trace *it, initcall_t fn) /* Get its name now since this function could * disappear because it is in the .init section. */ - sprint_symbol(it->func, (unsigned long)fn); + sprint_symbol(bt->func, (unsigned long)fn); + preempt_disable(); + + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), + &irq_flags); + if (!event) + goto out; + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, 0, 0); + entry->ent.type = TRACE_BOOT_CALL; + entry->boot_call = *bt; + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + trace_wake_up(); + + out: + preempt_enable(); +} + +void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) +{ + struct ring_buffer_event *event; + struct trace_boot_ret *entry; + unsigned long irq_flags; + struct trace_array *tr = boot_trace; + + if (!pre_initcalls_finished) + return; + + sprint_symbol(bt->func, (unsigned long)fn); preempt_disable(); - data = tr->data[smp_processor_id()]; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); @@ -121,8 +184,8 @@ void trace_boot(struct boot_trace *it, initcall_t fn) goto out; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, 0, 0); - entry->ent.type = TRACE_BOOT; - entry->initcall = *it; + entry->ent.type = TRACE_BOOT_RET; + entry->boot_ret = *bt; ring_buffer_unlock_commit(tr->buffer, event, irq_flags); trace_wake_up(); -- cgit v1.1 From 642edba5f5c545772b89907cf96134c73d6073c7 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 00:01:26 -0500 Subject: ring-buffer: fix deadlock from reader_lock in read_start Impact: deadlock fix in ring_buffer_read_start The ring_buffer_iter_reset was called from ring_buffer_read_start where both grabbed the reader_lock. This patch separates out the internals of ring_buffer_iter_reset to its own function so that both APIs may grab the reader_lock. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c04c433..86dc353 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1475,19 +1475,9 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer) return overruns; } -/** - * ring_buffer_iter_reset - reset an iterator - * @iter: The iterator to reset - * - * Resets the iterator, so that it will start from the beginning - * again. - */ -void ring_buffer_iter_reset(struct ring_buffer_iter *iter) +static void rb_iter_reset(struct ring_buffer_iter *iter) { struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; - unsigned long flags; - - spin_lock_irqsave(&cpu_buffer->reader_lock, flags); /* Iterator usage is expected to have record disabled */ if (list_empty(&cpu_buffer->reader_page->list)) { @@ -1501,7 +1491,22 @@ void ring_buffer_iter_reset(struct ring_buffer_iter *iter) iter->read_stamp = cpu_buffer->read_stamp; else iter->read_stamp = iter->head_page->time_stamp; +} +/** + * ring_buffer_iter_reset - reset an iterator + * @iter: The iterator to reset + * + * Resets the iterator, so that it will start from the beginning + * again. + */ +void ring_buffer_iter_reset(struct ring_buffer_iter *iter) +{ + struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; + unsigned long flags; + + spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + rb_iter_reset(iter); spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); } @@ -1957,7 +1962,7 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu) spin_lock_irqsave(&cpu_buffer->reader_lock, flags); __raw_spin_lock(&cpu_buffer->lock); - ring_buffer_iter_reset(iter); + rb_iter_reset(iter); __raw_spin_unlock(&cpu_buffer->lock); spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); -- cgit v1.1 From 1f0d69a9fc815db82f15722bf05227190b1d714d Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 00:14:39 -0500 Subject: tracing: profile likely and unlikely annotations Impact: new unlikely/likely profiler Andrew Morton recently suggested having an in-kernel way to profile likely and unlikely macros. This patch achieves that goal. When configured, every(*) likely and unlikely macro gets a counter attached to it. When the condition is hit, the hit and misses of that condition are recorded. These numbers can later be retrieved by: /debugfs/tracing/profile_likely - All likely markers /debugfs/tracing/profile_unlikely - All unlikely markers. # cat /debug/tracing/profile_unlikely | head correct incorrect % Function File Line ------- --------- - -------- ---- ---- 2167 0 0 do_arch_prctl process_64.c 832 0 0 0 do_arch_prctl process_64.c 804 2670 0 0 IS_ERR err.h 34 71230 5693 7 __switch_to process_64.c 673 76919 0 0 __switch_to process_64.c 639 43184 33743 43 __switch_to process_64.c 624 12740 64181 83 __switch_to process_64.c 594 12740 64174 83 __switch_to process_64.c 590 # cat /debug/tracing/profile_unlikely | \ awk '{ if ($3 > 25) print $0; }' |head -20 44963 35259 43 __switch_to process_64.c 624 12762 67454 84 __switch_to process_64.c 594 12762 67447 84 __switch_to process_64.c 590 1478 595 28 syscall_get_error syscall.h 51 0 2821 100 syscall_trace_leave ptrace.c 1567 0 1 100 native_smp_prepare_cpus smpboot.c 1237 86338 265881 75 calc_delta_fair sched_fair.c 408 210410 108540 34 calc_delta_mine sched.c 1267 0 54550 100 sched_info_queued sched_stats.h 222 51899 66435 56 pick_next_task_fair sched_fair.c 1422 6 10 62 yield_task_fair sched_fair.c 982 7325 2692 26 rt_policy sched.c 144 0 1270 100 pre_schedule_rt sched_rt.c 1261 1268 48073 97 pick_next_task_rt sched_rt.c 884 0 45181 100 sched_info_dequeued sched_stats.h 177 0 15 100 sched_move_task sched.c 8700 0 15 100 sched_move_task sched.c 8690 53167 33217 38 schedule sched.c 4457 0 80208 100 sched_info_switch sched_stats.h 270 30585 49631 61 context_switch sched.c 2619 # cat /debug/tracing/profile_likely | awk '{ if ($3 > 25) print $0; }' 39900 36577 47 pick_next_task sched.c 4397 20824 15233 42 switch_mm mmu_context_64.h 18 0 7 100 __cancel_work_timer workqueue.c 560 617 66484 99 clocksource_adjust timekeeping.c 456 0 346340 100 audit_syscall_exit auditsc.c 1570 38 347350 99 audit_get_context auditsc.c 732 0 345244 100 audit_syscall_entry auditsc.c 1541 38 1017 96 audit_free auditsc.c 1446 0 1090 100 audit_alloc auditsc.c 862 2618 1090 29 audit_alloc auditsc.c 858 0 6 100 move_masked_irq migration.c 9 1 198 99 probe_sched_wakeup trace_sched_switch.c 58 2 2 50 probe_wakeup trace_sched_wakeup.c 227 0 2 100 probe_wakeup_sched_switch trace_sched_wakeup.c 144 4514 2090 31 __grab_cache_page filemap.c 2149 12882 228786 94 mapping_unevictable pagemap.h 50 4 11 73 __flush_cpu_slab slub.c 1466 627757 330451 34 slab_free slub.c 1731 2959 61245 95 dentry_lru_del_init dcache.c 153 946 1217 56 load_elf_binary binfmt_elf.c 904 102 82 44 disk_put_part genhd.h 206 1 1 50 dst_gc_task dst.c 82 0 19 100 tcp_mss_split_point tcp_output.c 1126 As you can see by the above, there's a bit of work to do in rethinking the use of some unlikelys and likelys. Note: the unlikely case had 71 hits that were more than 25%. Note: After submitting my first version of this patch, Andrew Morton showed me a version written by Daniel Walker, where I picked up the following ideas from: 1) Using __builtin_constant_p to avoid profiling fixed values. 2) Using __FILE__ instead of instruction pointers. 3) Using the preprocessor to stop all profiling of likely annotations from vsyscall_64.c. Thanks to Andrew Morton, Arjan van de Ven, Theodore Tso and Ingo Molnar for their feed back on this patch. (*) Not ever unlikely is recorded, those that are used by vsyscalls (a few of them) had to have profiling disabled. Signed-off-by: Steven Rostedt Cc: Andrew Morton Cc: Frederic Weisbecker Cc: Theodore Tso Cc: Arjan van de Ven Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 16 +++++ kernel/trace/Makefile | 1 + kernel/trace/trace_unlikely.c | 164 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 181 insertions(+) create mode 100644 kernel/trace/trace_unlikely.c (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d986216..a604f24 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -159,6 +159,22 @@ config BOOT_TRACER selected, because the self-tests are an initcall as well and that would invalidate the boot trace. ) +config TRACE_UNLIKELY_PROFILE + bool "Trace likely/unlikely profiler" + depends on DEBUG_KERNEL + select TRACING + help + This tracer profiles all the the likely and unlikely macros + in the kernel. It will display the results in: + + /debugfs/tracing/profile_likely + /debugfs/tracing/profile_unlikely + + Note: this will add a significant overhead, only turn this + on if you need to profile the system's use of these macros. + + Say N if unsure. + config STACK_TRACER bool "Trace max stack" depends on HAVE_FUNCTION_TRACER diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 3e1f361..98e70ee 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -25,5 +25,6 @@ obj-$(CONFIG_STACK_TRACER) += trace_stack.o obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o +obj-$(CONFIG_TRACE_UNLIKELY_PROFILE) += trace_unlikely.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c new file mode 100644 index 0000000..9493269 --- /dev/null +++ b/kernel/trace/trace_unlikely.c @@ -0,0 +1,164 @@ +/* + * unlikely profiler + * + * Copyright (C) 2008 Steven Rostedt + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace.h" + +void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect) +{ + /* FIXME: Make this atomic! */ + if (val == expect) + f->correct++; + else + f->incorrect++; +} +EXPORT_SYMBOL(ftrace_likely_update); + +struct ftrace_pointer { + void *start; + void *stop; +}; + +static void * +t_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct ftrace_pointer *f = m->private; + struct ftrace_likely_data *p = v; + + (*pos)++; + + if (v == (void *)1) + return f->start; + + ++p; + + if ((void *)p >= (void *)f->stop) + return NULL; + + return p; +} + +static void *t_start(struct seq_file *m, loff_t *pos) +{ + void *t = (void *)1; + loff_t l = 0; + + for (; t && l < *pos; t = t_next(m, t, &l)) + ; + + return t; +} + +static void t_stop(struct seq_file *m, void *p) +{ +} + +static int t_show(struct seq_file *m, void *v) +{ + struct ftrace_likely_data *p = v; + const char *f; + unsigned long percent; + + if (v == (void *)1) { + seq_printf(m, " correct incorrect %% " + " Function " + " File Line\n" + " ------- --------- - " + " -------- " + " ---- ----\n"); + return 0; + } + + /* Only print the file, not the path */ + f = p->file + strlen(p->file); + while (f >= p->file && *f != '/') + f--; + f++; + + if (p->correct) { + percent = p->incorrect * 100; + percent /= p->correct + p->incorrect; + } else + percent = p->incorrect ? 100 : 0; + + seq_printf(m, "%8lu %8lu %3lu ", p->correct, p->incorrect, percent); + seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); + return 0; +} + +static struct seq_operations tracing_likely_seq_ops = { + .start = t_start, + .next = t_next, + .stop = t_stop, + .show = t_show, +}; + +static int tracing_likely_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = seq_open(file, &tracing_likely_seq_ops); + if (!ret) { + struct seq_file *m = file->private_data; + m->private = (void *)inode->i_private; + } + + return ret; +} + +static struct file_operations tracing_likely_fops = { + .open = tracing_likely_open, + .read = seq_read, + .llseek = seq_lseek, +}; + +extern unsigned long __start_likely_profile[]; +extern unsigned long __stop_likely_profile[]; +extern unsigned long __start_unlikely_profile[]; +extern unsigned long __stop_unlikely_profile[]; + +static struct ftrace_pointer ftrace_likely_pos = { + .start = __start_likely_profile, + .stop = __stop_likely_profile, +}; + +static struct ftrace_pointer ftrace_unlikely_pos = { + .start = __start_unlikely_profile, + .stop = __stop_unlikely_profile, +}; + +static __init int ftrace_unlikely_init(void) +{ + struct dentry *d_tracer; + struct dentry *entry; + + d_tracer = tracing_init_dentry(); + + entry = debugfs_create_file("profile_likely", 0444, d_tracer, + &ftrace_likely_pos, + &tracing_likely_fops); + if (!entry) + pr_warning("Could not create debugfs 'profile_likely' entry\n"); + + entry = debugfs_create_file("profile_unlikely", 0444, d_tracer, + &ftrace_unlikely_pos, + &tracing_likely_fops); + if (!entry) + pr_warning("Could not create debugfs" + " 'profile_unlikely' entry\n"); + + return 0; +} + +device_initcall(ftrace_unlikely_init); -- cgit v1.1 From 52f232cb720a7babb752849cbc2cab2d24021209 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 00:14:40 -0500 Subject: tracing: likely/unlikely branch annotation tracer Impact: new likely/unlikely branch tracer This patch adds a way to record the instances of the likely() and unlikely() branch condition annotations. When "unlikely" is set in /debugfs/tracing/iter_ctrl the unlikely conditions will be added to any of the ftrace tracers. The change takes effect when a new tracer is passed into the current_tracer file. For example: bash-3471 [003] 357.014755: [INCORRECT] sched_info_dequeued:sched_stats.h:177 bash-3471 [003] 357.014756: [correct] update_curr:sched_fair.c:489 bash-3471 [003] 357.014758: [correct] calc_delta_fair:sched_fair.c:411 bash-3471 [003] 357.014759: [correct] account_group_exec_runtime:sched_stats.h:356 bash-3471 [003] 357.014761: [correct] update_curr:sched_fair.c:489 bash-3471 [003] 357.014763: [INCORRECT] calc_delta_fair:sched_fair.c:411 bash-3471 [003] 357.014765: [correct] calc_delta_mine:sched.c:1279 Which shows the normal tracer heading, as well as whether the condition was correct "[correct]" or was mistaken "[INCORRECT]", followed by the function, file name and line number. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 22 ++++++++ kernel/trace/Makefile | 6 +++ kernel/trace/trace.c | 29 +++++++++++ kernel/trace/trace.h | 39 +++++++++++++++ kernel/trace/trace_unlikely.c | 114 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 210 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index a604f24..8abcaf8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -175,6 +175,28 @@ config TRACE_UNLIKELY_PROFILE Say N if unsure. +config TRACING_UNLIKELY + bool + help + Selected by tracers that will trace the likely and unlikely + conditions. This prevents the tracers themselves from being + profiled. Profiling the tracing infrastructure can only happen + when the likelys and unlikelys are not being traced. + +config UNLIKELY_TRACER + bool "Trace likely/unlikely instances" + depends on TRACE_UNLIKELY_PROFILE + select TRACING_UNLIKELY + help + This traces the events of likely and unlikely condition + calls in the kernel. The difference between this and the + "Trace likely/unlikely profiler" is that this is not a + histogram of the callers, but actually places the calling + events into a running trace buffer to see when and where the + events happened, as well as their results. + + Say N if unsure. + config STACK_TRACER bool "Trace max stack" depends on HAVE_FUNCTION_TRACER diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 98e70ee..c938d03 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -10,6 +10,12 @@ CFLAGS_trace_selftest_dynamic.o = -pg obj-y += trace_selftest_dynamic.o endif +# If unlikely tracing is enabled, do not trace these files +ifdef CONFIG_TRACING_UNLIKELY +KBUILD_CFLAGS += '-Dlikely(x)=likely_notrace(x)' +KBUILD_CFLAGS += '-Dunlikely(x)=unlikely_notrace(x)' +endif + obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o obj-$(CONFIG_RING_BUFFER) += ring_buffer.o diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a3f7ae9..83d3863 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -258,6 +258,9 @@ static const char *trace_options[] = { "sched-tree", "ftrace_printk", "ftrace_preempt", +#ifdef CONFIG_UNLIKELY_TRACER + "unlikely", +#endif NULL }; @@ -1648,6 +1651,18 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_seq_print_cont(s, iter); break; } + case TRACE_UNLIKELY: { + struct trace_unlikely *field; + + trace_assign_type(field, entry); + + trace_seq_printf(s, "[%s] %s:%s:%d\n", + field->correct ? "correct" : "INCORRECT", + field->func, + field->file, + field->line); + break; + } default: trace_seq_printf(s, "Unknown type %d\n", entry->type); } @@ -1787,6 +1802,18 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) return print_return_function(iter); break; } + case TRACE_UNLIKELY: { + struct trace_unlikely *field; + + trace_assign_type(field, entry); + + trace_seq_printf(s, "[%s] %s:%s:%d\n", + field->correct ? "correct" : "INCORRECT", + field->func, + field->file, + field->line); + break; + } } return TRACE_TYPE_HANDLED; } @@ -2592,6 +2619,7 @@ static int tracing_set_tracer(char *buf) if (t == current_trace) goto out; + trace_unlikely_disable(); if (current_trace && current_trace->reset) current_trace->reset(tr); @@ -2599,6 +2627,7 @@ static int tracing_set_tracer(char *buf) if (t->init) t->init(tr); + trace_unlikely_enable(tr); out: mutex_unlock(&trace_types_lock); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b5f91f1..9635aa2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -22,6 +22,7 @@ enum trace_type { TRACE_SPECIAL, TRACE_MMIO_RW, TRACE_MMIO_MAP, + TRACE_UNLIKELY, TRACE_BOOT_CALL, TRACE_BOOT_RET, TRACE_FN_RET, @@ -134,6 +135,16 @@ struct trace_boot_ret { struct boot_trace_ret boot_ret; }; +#define TRACE_FUNC_SIZE 30 +#define TRACE_FILE_SIZE 20 +struct trace_unlikely { + struct trace_entry ent; + unsigned line; + char func[TRACE_FUNC_SIZE+1]; + char file[TRACE_FILE_SIZE+1]; + char correct; +}; + /* * trace_flag_type is an enumeration that holds different * states when a trace occurs. These are: @@ -236,6 +247,7 @@ extern void __ftrace_bad_type(void); TRACE_MMIO_MAP); \ IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\ IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\ + IF_ASSIGN(var, ent, struct trace_unlikely, TRACE_UNLIKELY); \ IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET);\ __ftrace_bad_type(); \ } while (0) @@ -456,6 +468,9 @@ enum trace_iterator_flags { TRACE_ITER_SCHED_TREE = 0x200, TRACE_ITER_PRINTK = 0x400, TRACE_ITER_PREEMPTONLY = 0x800, +#ifdef CONFIG_UNLIKELY_TRACER + TRACE_ITER_UNLIKELY = 0x1000, +#endif }; /* @@ -515,4 +530,28 @@ static inline void ftrace_preempt_enable(int resched) preempt_enable_notrace(); } +#ifdef CONFIG_UNLIKELY_TRACER +extern int enable_unlikely_tracing(struct trace_array *tr); +extern void disable_unlikely_tracing(void); +static inline int trace_unlikely_enable(struct trace_array *tr) +{ + if (trace_flags & TRACE_ITER_UNLIKELY) + return enable_unlikely_tracing(tr); + return 0; +} +static inline void trace_unlikely_disable(void) +{ + /* due to races, always disable */ + disable_unlikely_tracing(); +} +#else +static inline int trace_unlikely_enable(struct trace_array *tr) +{ + return 0; +} +static inline void trace_unlikely_disable(void) +{ +} +#endif /* CONFIG_UNLIKELY_TRACER */ + #endif /* _LINUX_KERNEL_TRACE_H */ diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c index 9493269..7290e0e 100644 --- a/kernel/trace/trace_unlikely.c +++ b/kernel/trace/trace_unlikely.c @@ -15,8 +15,122 @@ #include #include "trace.h" +#ifdef CONFIG_UNLIKELY_TRACER + +static int unlikely_tracing_enabled __read_mostly; +static DEFINE_MUTEX(unlikely_tracing_mutex); +static struct trace_array *unlikely_tracer; + +static void +probe_likely_condition(struct ftrace_likely_data *f, int val, int expect) +{ + struct trace_array *tr = unlikely_tracer; + struct ring_buffer_event *event; + struct trace_unlikely *entry; + unsigned long flags, irq_flags; + int cpu, pc; + const char *p; + + /* + * I would love to save just the ftrace_likely_data pointer, but + * this code can also be used by modules. Ugly things can happen + * if the module is unloaded, and then we go and read the + * pointer. This is slower, but much safer. + */ + + if (unlikely(!tr)) + return; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) + goto out; + + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), + &irq_flags); + if (!event) + goto out; + + pc = preempt_count(); + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, flags, pc); + entry->ent.type = TRACE_UNLIKELY; + + /* Strip off the path, only save the file */ + p = f->file + strlen(f->file); + while (p >= f->file && *p != '/') + p--; + p++; + + strncpy(entry->func, f->func, TRACE_FUNC_SIZE); + strncpy(entry->file, p, TRACE_FILE_SIZE); + entry->func[TRACE_FUNC_SIZE] = 0; + entry->file[TRACE_FILE_SIZE] = 0; + entry->line = f->line; + entry->correct = val == expect; + + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + out: + atomic_dec(&tr->data[cpu]->disabled); + local_irq_restore(flags); +} + +static inline +void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) +{ + if (!unlikely_tracing_enabled) + return; + + probe_likely_condition(f, val, expect); +} + +int enable_unlikely_tracing(struct trace_array *tr) +{ + int ret = 0; + + mutex_lock(&unlikely_tracing_mutex); + unlikely_tracer = tr; + /* + * Must be seen before enabling. The reader is a condition + * where we do not need a matching rmb() + */ + smp_wmb(); + unlikely_tracing_enabled++; + mutex_unlock(&unlikely_tracing_mutex); + + return ret; +} + +void disable_unlikely_tracing(void) +{ + mutex_lock(&unlikely_tracing_mutex); + + if (!unlikely_tracing_enabled) + goto out_unlock; + + unlikely_tracing_enabled--; + + out_unlock: + mutex_unlock(&unlikely_tracing_mutex); +} +#else +static inline +void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) +{ +} +#endif /* CONFIG_UNLIKELY_TRACER */ + void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect) { + /* + * I would love to have a trace point here instead, but the + * trace point code is so inundated with unlikely and likely + * conditions that the recursive nightmare that exists is too + * much to try to get working. At least for now. + */ + trace_likely_condition(f, val, expect); + /* FIXME: Make this atomic! */ if (val == expect) f->correct++; -- cgit v1.1 From f88c4ae9f8c3939bee4337c75c7a673b5de7a8a7 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 12 Nov 2008 11:55:41 +0100 Subject: tracing: branch tracer, tweak output Impact: modify the tracer output, to make it a bit easier to read Change the output from: > bash-3471 [003] 357.014755: [INCORRECT] sched_info_dequeued:sched_stats.h:177 > bash-3471 [003] 357.014756: [correct] update_curr:sched_fair.c:489 > bash-3471 [003] 357.014758: [correct] calc_delta_fair:sched_fair.c:411 to: > bash-3471 [003] 357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177 > bash-3471 [003] 357.014756: [ .... ] update_curr:sched_fair.c:489 > bash-3471 [003] 357.014758: [ .... ] calc_delta_fair:sched_fair.c:411 it's good to have fields aligned vertically, and the only important information is a prediction miss, so display only that information. Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 83d3863..728a46e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1657,7 +1657,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_assign_type(field, entry); trace_seq_printf(s, "[%s] %s:%s:%d\n", - field->correct ? "correct" : "INCORRECT", + field->correct ? " .... " : " MISS ", field->func, field->file, field->line); @@ -1808,7 +1808,7 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) trace_assign_type(field, entry); trace_seq_printf(s, "[%s] %s:%s:%d\n", - field->correct ? "correct" : "INCORRECT", + field->correct ? " .... " : " MISS ", field->func, field->file, field->line); -- cgit v1.1 From 68d119f0a66f7e3663304343b072e56a2693446b Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 12 Nov 2008 14:09:30 +0100 Subject: tracing: finetune branch-tracer output Steve suggested the to change the output from this: > bash-3471 [003] 357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177 > bash-3471 [003] 357.014756: [ .... ] update_curr:sched_fair.c:489 > bash-3471 [003] 357.014758: [ .... ] calc_delta_fair:sched_fair.c:411 to this: > bash-3471 [003] 357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177 > bash-3471 [003] 357.014756: [ ok ] update_curr:sched_fair.c:489 > bash-3471 [003] 357.014758: [ ok ] calc_delta_fair:sched_fair.c:411 as it makes it clearer to the user what it means exactly. Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 728a46e..d842db1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1657,7 +1657,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_assign_type(field, entry); trace_seq_printf(s, "[%s] %s:%s:%d\n", - field->correct ? " .... " : " MISS ", + field->correct ? " ok " : " MISS ", field->func, field->file, field->line); @@ -1808,7 +1808,7 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) trace_assign_type(field, entry); trace_seq_printf(s, "[%s] %s:%s:%d\n", - field->correct ? " .... " : " MISS ", + field->correct ? " ok " : " MISS ", field->func, field->file, field->line); -- cgit v1.1 From 2ed84eeb8808cf3c9f039213ca137ffd7d753f0e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 15:24:24 -0500 Subject: trace: rename unlikely profiler to branch profiler Impact: name change of unlikely tracer and profiler Ingo Molnar suggested changing the config from UNLIKELY_PROFILE to BRANCH_PROFILING. I never did like the "unlikely" name so I went one step farther, and renamed all the unlikely configurations to a "BRANCH" variant. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 10 +++++----- kernel/trace/Makefile | 7 +++---- kernel/trace/trace.c | 2 +- kernel/trace/trace.h | 6 +++--- kernel/trace/trace_unlikely.c | 4 ++-- 5 files changed, 14 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 8abcaf8..9c89526 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -159,7 +159,7 @@ config BOOT_TRACER selected, because the self-tests are an initcall as well and that would invalidate the boot trace. ) -config TRACE_UNLIKELY_PROFILE +config TRACE_BRANCH_PROFILING bool "Trace likely/unlikely profiler" depends on DEBUG_KERNEL select TRACING @@ -175,7 +175,7 @@ config TRACE_UNLIKELY_PROFILE Say N if unsure. -config TRACING_UNLIKELY +config TRACING_BRANCHES bool help Selected by tracers that will trace the likely and unlikely @@ -183,10 +183,10 @@ config TRACING_UNLIKELY profiled. Profiling the tracing infrastructure can only happen when the likelys and unlikelys are not being traced. -config UNLIKELY_TRACER +config BRANCH_TRACER bool "Trace likely/unlikely instances" - depends on TRACE_UNLIKELY_PROFILE - select TRACING_UNLIKELY + depends on TRACE_BRANCH_PROFILING + select TRACING_BRANCHES help This traces the events of likely and unlikely condition calls in the kernel. The difference between this and the diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index c938d03..0087df7 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -11,9 +11,8 @@ obj-y += trace_selftest_dynamic.o endif # If unlikely tracing is enabled, do not trace these files -ifdef CONFIG_TRACING_UNLIKELY -KBUILD_CFLAGS += '-Dlikely(x)=likely_notrace(x)' -KBUILD_CFLAGS += '-Dunlikely(x)=unlikely_notrace(x)' +ifdef CONFIG_TRACING_BRANCHES +KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING endif obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o @@ -31,6 +30,6 @@ obj-$(CONFIG_STACK_TRACER) += trace_stack.o obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o -obj-$(CONFIG_TRACE_UNLIKELY_PROFILE) += trace_unlikely.o +obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_unlikely.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d842db1..bad59d3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -258,7 +258,7 @@ static const char *trace_options[] = { "sched-tree", "ftrace_printk", "ftrace_preempt", -#ifdef CONFIG_UNLIKELY_TRACER +#ifdef CONFIG_BRANCH_TRACER "unlikely", #endif NULL diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9635aa2..dccae63 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -468,7 +468,7 @@ enum trace_iterator_flags { TRACE_ITER_SCHED_TREE = 0x200, TRACE_ITER_PRINTK = 0x400, TRACE_ITER_PREEMPTONLY = 0x800, -#ifdef CONFIG_UNLIKELY_TRACER +#ifdef CONFIG_BRANCH_TRACER TRACE_ITER_UNLIKELY = 0x1000, #endif }; @@ -530,7 +530,7 @@ static inline void ftrace_preempt_enable(int resched) preempt_enable_notrace(); } -#ifdef CONFIG_UNLIKELY_TRACER +#ifdef CONFIG_BRANCH_TRACER extern int enable_unlikely_tracing(struct trace_array *tr); extern void disable_unlikely_tracing(void); static inline int trace_unlikely_enable(struct trace_array *tr) @@ -552,6 +552,6 @@ static inline int trace_unlikely_enable(struct trace_array *tr) static inline void trace_unlikely_disable(void) { } -#endif /* CONFIG_UNLIKELY_TRACER */ +#endif /* CONFIG_BRANCH_TRACER */ #endif /* _LINUX_KERNEL_TRACE_H */ diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c index 7290e0e..856eb3b 100644 --- a/kernel/trace/trace_unlikely.c +++ b/kernel/trace/trace_unlikely.c @@ -15,7 +15,7 @@ #include #include "trace.h" -#ifdef CONFIG_UNLIKELY_TRACER +#ifdef CONFIG_BRANCH_TRACER static int unlikely_tracing_enabled __read_mostly; static DEFINE_MUTEX(unlikely_tracing_mutex); @@ -119,7 +119,7 @@ static inline void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) { } -#endif /* CONFIG_UNLIKELY_TRACER */ +#endif /* CONFIG_BRANCH_TRACER */ void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect) { -- cgit v1.1 From 9f029e83e968e5661d7be045bbcb620dbb909938 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 15:24:24 -0500 Subject: ftrace: rename unlikely iter_ctrl to branch Impact: rename of iter_ctrl unlikely to branch The unlikely name is ugly. This patch converts the iter_ctrl command "unlikely" and "nounlikely" to "branch" and "nobranch" respectively. It also renames a lot of internal functions to use "branch" instead of "unlikely". Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 14 ++++++------ kernel/trace/trace.h | 26 +++++++++++----------- kernel/trace/trace_unlikely.c | 50 +++++++++++++++++++++---------------------- 3 files changed, 45 insertions(+), 45 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bad59d3..4bf070b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -259,7 +259,7 @@ static const char *trace_options[] = { "ftrace_printk", "ftrace_preempt", #ifdef CONFIG_BRANCH_TRACER - "unlikely", + "branch", #endif NULL }; @@ -1651,8 +1651,8 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_seq_print_cont(s, iter); break; } - case TRACE_UNLIKELY: { - struct trace_unlikely *field; + case TRACE_BRANCH: { + struct trace_branch *field; trace_assign_type(field, entry); @@ -1802,8 +1802,8 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) return print_return_function(iter); break; } - case TRACE_UNLIKELY: { - struct trace_unlikely *field; + case TRACE_BRANCH: { + struct trace_branch *field; trace_assign_type(field, entry); @@ -2619,7 +2619,7 @@ static int tracing_set_tracer(char *buf) if (t == current_trace) goto out; - trace_unlikely_disable(); + trace_branch_disable(); if (current_trace && current_trace->reset) current_trace->reset(tr); @@ -2627,7 +2627,7 @@ static int tracing_set_tracer(char *buf) if (t->init) t->init(tr); - trace_unlikely_enable(tr); + trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index dccae63..7fbf37b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -22,7 +22,7 @@ enum trace_type { TRACE_SPECIAL, TRACE_MMIO_RW, TRACE_MMIO_MAP, - TRACE_UNLIKELY, + TRACE_BRANCH, TRACE_BOOT_CALL, TRACE_BOOT_RET, TRACE_FN_RET, @@ -137,7 +137,7 @@ struct trace_boot_ret { #define TRACE_FUNC_SIZE 30 #define TRACE_FILE_SIZE 20 -struct trace_unlikely { +struct trace_branch { struct trace_entry ent; unsigned line; char func[TRACE_FUNC_SIZE+1]; @@ -247,7 +247,7 @@ extern void __ftrace_bad_type(void); TRACE_MMIO_MAP); \ IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\ IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\ - IF_ASSIGN(var, ent, struct trace_unlikely, TRACE_UNLIKELY); \ + IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \ IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET);\ __ftrace_bad_type(); \ } while (0) @@ -469,7 +469,7 @@ enum trace_iterator_flags { TRACE_ITER_PRINTK = 0x400, TRACE_ITER_PREEMPTONLY = 0x800, #ifdef CONFIG_BRANCH_TRACER - TRACE_ITER_UNLIKELY = 0x1000, + TRACE_ITER_BRANCH = 0x1000, #endif }; @@ -531,25 +531,25 @@ static inline void ftrace_preempt_enable(int resched) } #ifdef CONFIG_BRANCH_TRACER -extern int enable_unlikely_tracing(struct trace_array *tr); -extern void disable_unlikely_tracing(void); -static inline int trace_unlikely_enable(struct trace_array *tr) +extern int enable_branch_tracing(struct trace_array *tr); +extern void disable_branch_tracing(void); +static inline int trace_branch_enable(struct trace_array *tr) { - if (trace_flags & TRACE_ITER_UNLIKELY) - return enable_unlikely_tracing(tr); + if (trace_flags & TRACE_ITER_BRANCH) + return enable_branch_tracing(tr); return 0; } -static inline void trace_unlikely_disable(void) +static inline void trace_branch_disable(void) { /* due to races, always disable */ - disable_unlikely_tracing(); + disable_branch_tracing(); } #else -static inline int trace_unlikely_enable(struct trace_array *tr) +static inline int trace_branch_enable(struct trace_array *tr) { return 0; } -static inline void trace_unlikely_disable(void) +static inline void trace_branch_disable(void) { } #endif /* CONFIG_BRANCH_TRACER */ diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c index 856eb3b..e5d5969 100644 --- a/kernel/trace/trace_unlikely.c +++ b/kernel/trace/trace_unlikely.c @@ -17,16 +17,16 @@ #ifdef CONFIG_BRANCH_TRACER -static int unlikely_tracing_enabled __read_mostly; -static DEFINE_MUTEX(unlikely_tracing_mutex); -static struct trace_array *unlikely_tracer; +static int branch_tracing_enabled __read_mostly; +static DEFINE_MUTEX(branch_tracing_mutex); +static struct trace_array *branch_tracer; static void -probe_likely_condition(struct ftrace_likely_data *f, int val, int expect) +probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) { - struct trace_array *tr = unlikely_tracer; + struct trace_array *tr = branch_tracer; struct ring_buffer_event *event; - struct trace_unlikely *entry; + struct trace_branch *entry; unsigned long flags, irq_flags; int cpu, pc; const char *p; @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_likely_data *f, int val, int expect) pc = preempt_count(); entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); - entry->ent.type = TRACE_UNLIKELY; + entry->ent.type = TRACE_BRANCH; /* Strip off the path, only save the file */ p = f->file + strlen(f->file); @@ -77,51 +77,51 @@ probe_likely_condition(struct ftrace_likely_data *f, int val, int expect) } static inline -void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) +void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) { - if (!unlikely_tracing_enabled) + if (!branch_tracing_enabled) return; probe_likely_condition(f, val, expect); } -int enable_unlikely_tracing(struct trace_array *tr) +int enable_branch_tracing(struct trace_array *tr) { int ret = 0; - mutex_lock(&unlikely_tracing_mutex); - unlikely_tracer = tr; + mutex_lock(&branch_tracing_mutex); + branch_tracer = tr; /* * Must be seen before enabling. The reader is a condition * where we do not need a matching rmb() */ smp_wmb(); - unlikely_tracing_enabled++; - mutex_unlock(&unlikely_tracing_mutex); + branch_tracing_enabled++; + mutex_unlock(&branch_tracing_mutex); return ret; } -void disable_unlikely_tracing(void) +void disable_branch_tracing(void) { - mutex_lock(&unlikely_tracing_mutex); + mutex_lock(&branch_tracing_mutex); - if (!unlikely_tracing_enabled) + if (!branch_tracing_enabled) goto out_unlock; - unlikely_tracing_enabled--; + branch_tracing_enabled--; out_unlock: - mutex_unlock(&unlikely_tracing_mutex); + mutex_unlock(&branch_tracing_mutex); } #else static inline -void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) +void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) { } #endif /* CONFIG_BRANCH_TRACER */ -void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect) +void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect) { /* * I would love to have a trace point here instead, but the @@ -148,7 +148,7 @@ static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_pointer *f = m->private; - struct ftrace_likely_data *p = v; + struct ftrace_branch_data *p = v; (*pos)++; @@ -180,7 +180,7 @@ static void t_stop(struct seq_file *m, void *p) static int t_show(struct seq_file *m, void *v) { - struct ftrace_likely_data *p = v; + struct ftrace_branch_data *p = v; const char *f; unsigned long percent; @@ -252,7 +252,7 @@ static struct ftrace_pointer ftrace_unlikely_pos = { .stop = __stop_unlikely_profile, }; -static __init int ftrace_unlikely_init(void) +static __init int ftrace_branch_init(void) { struct dentry *d_tracer; struct dentry *entry; @@ -275,4 +275,4 @@ static __init int ftrace_unlikely_init(void) return 0; } -device_initcall(ftrace_unlikely_init); +device_initcall(ftrace_branch_init); -- cgit v1.1 From 80e5ea4506791af206266c5921c97f11d3b17866 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 15:24:24 -0500 Subject: ftrace: add tracer called branch Impact: added new branch tracer Currently the tracing of branch profiling (unlikelys and likelys hit) is only activated by the iter_ctrl. This patch adds a tracer called "branch" that will just trace the branch profiling. The advantage of adding this tracer is that it can be added to the ftrace selftests on startup. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.h | 2 ++ kernel/trace/trace_selftest.c | 23 +++++++++++++++++++++++ kernel/trace/trace_unlikely.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 67 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 7fbf37b..9e015f5 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -420,6 +420,8 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr); extern int trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr); +extern int trace_selftest_startup_branch(struct tracer *trace, + struct trace_array *tr); #endif /* CONFIG_FTRACE_STARTUP_TEST */ extern void *head_page(struct trace_array_cpu *data); diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 0728a10..24e6e07 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -13,6 +13,7 @@ static inline int trace_valid_entry(struct trace_entry *entry) case TRACE_STACK: case TRACE_PRINT: case TRACE_SPECIAL: + case TRACE_BRANCH: return 1; } return 0; @@ -544,3 +545,25 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr) return ret; } #endif /* CONFIG_SYSPROF_TRACER */ + +#ifdef CONFIG_BRANCH_TRACER +int +trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr) +{ + unsigned long count; + int ret; + + /* start the tracing */ + trace->init(tr); + /* Sleep for a 1/10 of a second */ + msleep(100); + /* stop the tracing. */ + tracing_stop(); + /* check the trace buffer */ + ret = trace_test_buffer(tr, &count); + trace->reset(tr); + tracing_start(); + + return ret; +} +#endif /* CONFIG_BRANCH_TRACER */ diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c index e5d5969..8526555 100644 --- a/kernel/trace/trace_unlikely.c +++ b/kernel/trace/trace_unlikely.c @@ -114,6 +114,48 @@ void disable_branch_tracing(void) out_unlock: mutex_unlock(&branch_tracing_mutex); } + +static void start_branch_trace(struct trace_array *tr) +{ + enable_branch_tracing(tr); +} + +static void stop_branch_trace(struct trace_array *tr) +{ + disable_branch_tracing(); +} + +static void branch_trace_init(struct trace_array *tr) +{ + int cpu; + + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); + + start_branch_trace(tr); +} + +static void branch_trace_reset(struct trace_array *tr) +{ + stop_branch_trace(tr); +} + +struct tracer branch_trace __read_mostly = +{ + .name = "branch", + .init = branch_trace_init, + .reset = branch_trace_reset, +#ifdef CONFIG_FTRACE_SELFTEST + .selftest = trace_selftest_startup_branch, +#endif +}; + +__init static int init_branch_trace(void) +{ + return register_tracer(&branch_trace); +} + +device_initcall(init_branch_trace); #else static inline void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) -- cgit v1.1 From 94b80ffd650b22e1fd493ccf6bad7efda4b8ea85 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 16:18:45 -0500 Subject: ftrace: rename trace_unlikely.c file Impact: File name change of trace_unlikely.c The "unlikely" name for the tracer is quite ugly. We renamed all the parts of it to "branch" and now it is time to rename the file too. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Makefile | 2 +- kernel/trace/trace_branch.c | 320 ++++++++++++++++++++++++++++++++++++++++++ kernel/trace/trace_unlikely.c | 320 ------------------------------------------ 3 files changed, 321 insertions(+), 321 deletions(-) create mode 100644 kernel/trace/trace_branch.c delete mode 100644 kernel/trace/trace_unlikely.c (limited to 'kernel') diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 0087df7..1a8c925 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -30,6 +30,6 @@ obj-$(CONFIG_STACK_TRACER) += trace_stack.o obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o -obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_unlikely.o +obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c new file mode 100644 index 0000000..8526555 --- /dev/null +++ b/kernel/trace/trace_branch.c @@ -0,0 +1,320 @@ +/* + * unlikely profiler + * + * Copyright (C) 2008 Steven Rostedt + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace.h" + +#ifdef CONFIG_BRANCH_TRACER + +static int branch_tracing_enabled __read_mostly; +static DEFINE_MUTEX(branch_tracing_mutex); +static struct trace_array *branch_tracer; + +static void +probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) +{ + struct trace_array *tr = branch_tracer; + struct ring_buffer_event *event; + struct trace_branch *entry; + unsigned long flags, irq_flags; + int cpu, pc; + const char *p; + + /* + * I would love to save just the ftrace_likely_data pointer, but + * this code can also be used by modules. Ugly things can happen + * if the module is unloaded, and then we go and read the + * pointer. This is slower, but much safer. + */ + + if (unlikely(!tr)) + return; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) + goto out; + + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), + &irq_flags); + if (!event) + goto out; + + pc = preempt_count(); + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, flags, pc); + entry->ent.type = TRACE_BRANCH; + + /* Strip off the path, only save the file */ + p = f->file + strlen(f->file); + while (p >= f->file && *p != '/') + p--; + p++; + + strncpy(entry->func, f->func, TRACE_FUNC_SIZE); + strncpy(entry->file, p, TRACE_FILE_SIZE); + entry->func[TRACE_FUNC_SIZE] = 0; + entry->file[TRACE_FILE_SIZE] = 0; + entry->line = f->line; + entry->correct = val == expect; + + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + out: + atomic_dec(&tr->data[cpu]->disabled); + local_irq_restore(flags); +} + +static inline +void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) +{ + if (!branch_tracing_enabled) + return; + + probe_likely_condition(f, val, expect); +} + +int enable_branch_tracing(struct trace_array *tr) +{ + int ret = 0; + + mutex_lock(&branch_tracing_mutex); + branch_tracer = tr; + /* + * Must be seen before enabling. The reader is a condition + * where we do not need a matching rmb() + */ + smp_wmb(); + branch_tracing_enabled++; + mutex_unlock(&branch_tracing_mutex); + + return ret; +} + +void disable_branch_tracing(void) +{ + mutex_lock(&branch_tracing_mutex); + + if (!branch_tracing_enabled) + goto out_unlock; + + branch_tracing_enabled--; + + out_unlock: + mutex_unlock(&branch_tracing_mutex); +} + +static void start_branch_trace(struct trace_array *tr) +{ + enable_branch_tracing(tr); +} + +static void stop_branch_trace(struct trace_array *tr) +{ + disable_branch_tracing(); +} + +static void branch_trace_init(struct trace_array *tr) +{ + int cpu; + + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); + + start_branch_trace(tr); +} + +static void branch_trace_reset(struct trace_array *tr) +{ + stop_branch_trace(tr); +} + +struct tracer branch_trace __read_mostly = +{ + .name = "branch", + .init = branch_trace_init, + .reset = branch_trace_reset, +#ifdef CONFIG_FTRACE_SELFTEST + .selftest = trace_selftest_startup_branch, +#endif +}; + +__init static int init_branch_trace(void) +{ + return register_tracer(&branch_trace); +} + +device_initcall(init_branch_trace); +#else +static inline +void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) +{ +} +#endif /* CONFIG_BRANCH_TRACER */ + +void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect) +{ + /* + * I would love to have a trace point here instead, but the + * trace point code is so inundated with unlikely and likely + * conditions that the recursive nightmare that exists is too + * much to try to get working. At least for now. + */ + trace_likely_condition(f, val, expect); + + /* FIXME: Make this atomic! */ + if (val == expect) + f->correct++; + else + f->incorrect++; +} +EXPORT_SYMBOL(ftrace_likely_update); + +struct ftrace_pointer { + void *start; + void *stop; +}; + +static void * +t_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct ftrace_pointer *f = m->private; + struct ftrace_branch_data *p = v; + + (*pos)++; + + if (v == (void *)1) + return f->start; + + ++p; + + if ((void *)p >= (void *)f->stop) + return NULL; + + return p; +} + +static void *t_start(struct seq_file *m, loff_t *pos) +{ + void *t = (void *)1; + loff_t l = 0; + + for (; t && l < *pos; t = t_next(m, t, &l)) + ; + + return t; +} + +static void t_stop(struct seq_file *m, void *p) +{ +} + +static int t_show(struct seq_file *m, void *v) +{ + struct ftrace_branch_data *p = v; + const char *f; + unsigned long percent; + + if (v == (void *)1) { + seq_printf(m, " correct incorrect %% " + " Function " + " File Line\n" + " ------- --------- - " + " -------- " + " ---- ----\n"); + return 0; + } + + /* Only print the file, not the path */ + f = p->file + strlen(p->file); + while (f >= p->file && *f != '/') + f--; + f++; + + if (p->correct) { + percent = p->incorrect * 100; + percent /= p->correct + p->incorrect; + } else + percent = p->incorrect ? 100 : 0; + + seq_printf(m, "%8lu %8lu %3lu ", p->correct, p->incorrect, percent); + seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); + return 0; +} + +static struct seq_operations tracing_likely_seq_ops = { + .start = t_start, + .next = t_next, + .stop = t_stop, + .show = t_show, +}; + +static int tracing_likely_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = seq_open(file, &tracing_likely_seq_ops); + if (!ret) { + struct seq_file *m = file->private_data; + m->private = (void *)inode->i_private; + } + + return ret; +} + +static struct file_operations tracing_likely_fops = { + .open = tracing_likely_open, + .read = seq_read, + .llseek = seq_lseek, +}; + +extern unsigned long __start_likely_profile[]; +extern unsigned long __stop_likely_profile[]; +extern unsigned long __start_unlikely_profile[]; +extern unsigned long __stop_unlikely_profile[]; + +static struct ftrace_pointer ftrace_likely_pos = { + .start = __start_likely_profile, + .stop = __stop_likely_profile, +}; + +static struct ftrace_pointer ftrace_unlikely_pos = { + .start = __start_unlikely_profile, + .stop = __stop_unlikely_profile, +}; + +static __init int ftrace_branch_init(void) +{ + struct dentry *d_tracer; + struct dentry *entry; + + d_tracer = tracing_init_dentry(); + + entry = debugfs_create_file("profile_likely", 0444, d_tracer, + &ftrace_likely_pos, + &tracing_likely_fops); + if (!entry) + pr_warning("Could not create debugfs 'profile_likely' entry\n"); + + entry = debugfs_create_file("profile_unlikely", 0444, d_tracer, + &ftrace_unlikely_pos, + &tracing_likely_fops); + if (!entry) + pr_warning("Could not create debugfs" + " 'profile_unlikely' entry\n"); + + return 0; +} + +device_initcall(ftrace_branch_init); diff --git a/kernel/trace/trace_unlikely.c b/kernel/trace/trace_unlikely.c deleted file mode 100644 index 8526555..0000000 --- a/kernel/trace/trace_unlikely.c +++ /dev/null @@ -1,320 +0,0 @@ -/* - * unlikely profiler - * - * Copyright (C) 2008 Steven Rostedt - */ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include "trace.h" - -#ifdef CONFIG_BRANCH_TRACER - -static int branch_tracing_enabled __read_mostly; -static DEFINE_MUTEX(branch_tracing_mutex); -static struct trace_array *branch_tracer; - -static void -probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) -{ - struct trace_array *tr = branch_tracer; - struct ring_buffer_event *event; - struct trace_branch *entry; - unsigned long flags, irq_flags; - int cpu, pc; - const char *p; - - /* - * I would love to save just the ftrace_likely_data pointer, but - * this code can also be used by modules. Ugly things can happen - * if the module is unloaded, and then we go and read the - * pointer. This is slower, but much safer. - */ - - if (unlikely(!tr)) - return; - - local_irq_save(flags); - cpu = raw_smp_processor_id(); - if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) - goto out; - - event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), - &irq_flags); - if (!event) - goto out; - - pc = preempt_count(); - entry = ring_buffer_event_data(event); - tracing_generic_entry_update(&entry->ent, flags, pc); - entry->ent.type = TRACE_BRANCH; - - /* Strip off the path, only save the file */ - p = f->file + strlen(f->file); - while (p >= f->file && *p != '/') - p--; - p++; - - strncpy(entry->func, f->func, TRACE_FUNC_SIZE); - strncpy(entry->file, p, TRACE_FILE_SIZE); - entry->func[TRACE_FUNC_SIZE] = 0; - entry->file[TRACE_FILE_SIZE] = 0; - entry->line = f->line; - entry->correct = val == expect; - - ring_buffer_unlock_commit(tr->buffer, event, irq_flags); - - out: - atomic_dec(&tr->data[cpu]->disabled); - local_irq_restore(flags); -} - -static inline -void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) -{ - if (!branch_tracing_enabled) - return; - - probe_likely_condition(f, val, expect); -} - -int enable_branch_tracing(struct trace_array *tr) -{ - int ret = 0; - - mutex_lock(&branch_tracing_mutex); - branch_tracer = tr; - /* - * Must be seen before enabling. The reader is a condition - * where we do not need a matching rmb() - */ - smp_wmb(); - branch_tracing_enabled++; - mutex_unlock(&branch_tracing_mutex); - - return ret; -} - -void disable_branch_tracing(void) -{ - mutex_lock(&branch_tracing_mutex); - - if (!branch_tracing_enabled) - goto out_unlock; - - branch_tracing_enabled--; - - out_unlock: - mutex_unlock(&branch_tracing_mutex); -} - -static void start_branch_trace(struct trace_array *tr) -{ - enable_branch_tracing(tr); -} - -static void stop_branch_trace(struct trace_array *tr) -{ - disable_branch_tracing(); -} - -static void branch_trace_init(struct trace_array *tr) -{ - int cpu; - - for_each_online_cpu(cpu) - tracing_reset(tr, cpu); - - start_branch_trace(tr); -} - -static void branch_trace_reset(struct trace_array *tr) -{ - stop_branch_trace(tr); -} - -struct tracer branch_trace __read_mostly = -{ - .name = "branch", - .init = branch_trace_init, - .reset = branch_trace_reset, -#ifdef CONFIG_FTRACE_SELFTEST - .selftest = trace_selftest_startup_branch, -#endif -}; - -__init static int init_branch_trace(void) -{ - return register_tracer(&branch_trace); -} - -device_initcall(init_branch_trace); -#else -static inline -void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) -{ -} -#endif /* CONFIG_BRANCH_TRACER */ - -void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect) -{ - /* - * I would love to have a trace point here instead, but the - * trace point code is so inundated with unlikely and likely - * conditions that the recursive nightmare that exists is too - * much to try to get working. At least for now. - */ - trace_likely_condition(f, val, expect); - - /* FIXME: Make this atomic! */ - if (val == expect) - f->correct++; - else - f->incorrect++; -} -EXPORT_SYMBOL(ftrace_likely_update); - -struct ftrace_pointer { - void *start; - void *stop; -}; - -static void * -t_next(struct seq_file *m, void *v, loff_t *pos) -{ - struct ftrace_pointer *f = m->private; - struct ftrace_branch_data *p = v; - - (*pos)++; - - if (v == (void *)1) - return f->start; - - ++p; - - if ((void *)p >= (void *)f->stop) - return NULL; - - return p; -} - -static void *t_start(struct seq_file *m, loff_t *pos) -{ - void *t = (void *)1; - loff_t l = 0; - - for (; t && l < *pos; t = t_next(m, t, &l)) - ; - - return t; -} - -static void t_stop(struct seq_file *m, void *p) -{ -} - -static int t_show(struct seq_file *m, void *v) -{ - struct ftrace_branch_data *p = v; - const char *f; - unsigned long percent; - - if (v == (void *)1) { - seq_printf(m, " correct incorrect %% " - " Function " - " File Line\n" - " ------- --------- - " - " -------- " - " ---- ----\n"); - return 0; - } - - /* Only print the file, not the path */ - f = p->file + strlen(p->file); - while (f >= p->file && *f != '/') - f--; - f++; - - if (p->correct) { - percent = p->incorrect * 100; - percent /= p->correct + p->incorrect; - } else - percent = p->incorrect ? 100 : 0; - - seq_printf(m, "%8lu %8lu %3lu ", p->correct, p->incorrect, percent); - seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); - return 0; -} - -static struct seq_operations tracing_likely_seq_ops = { - .start = t_start, - .next = t_next, - .stop = t_stop, - .show = t_show, -}; - -static int tracing_likely_open(struct inode *inode, struct file *file) -{ - int ret; - - ret = seq_open(file, &tracing_likely_seq_ops); - if (!ret) { - struct seq_file *m = file->private_data; - m->private = (void *)inode->i_private; - } - - return ret; -} - -static struct file_operations tracing_likely_fops = { - .open = tracing_likely_open, - .read = seq_read, - .llseek = seq_lseek, -}; - -extern unsigned long __start_likely_profile[]; -extern unsigned long __stop_likely_profile[]; -extern unsigned long __start_unlikely_profile[]; -extern unsigned long __stop_unlikely_profile[]; - -static struct ftrace_pointer ftrace_likely_pos = { - .start = __start_likely_profile, - .stop = __stop_likely_profile, -}; - -static struct ftrace_pointer ftrace_unlikely_pos = { - .start = __start_unlikely_profile, - .stop = __stop_unlikely_profile, -}; - -static __init int ftrace_branch_init(void) -{ - struct dentry *d_tracer; - struct dentry *entry; - - d_tracer = tracing_init_dentry(); - - entry = debugfs_create_file("profile_likely", 0444, d_tracer, - &ftrace_likely_pos, - &tracing_likely_fops); - if (!entry) - pr_warning("Could not create debugfs 'profile_likely' entry\n"); - - entry = debugfs_create_file("profile_unlikely", 0444, d_tracer, - &ftrace_unlikely_pos, - &tracing_likely_fops); - if (!entry) - pr_warning("Could not create debugfs" - " 'profile_unlikely' entry\n"); - - return 0; -} - -device_initcall(ftrace_branch_init); -- cgit v1.1 From a94c80e78bc9f4493ffc25a02d5d7bcd93c399d0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 17:52:36 -0500 Subject: ftrace: rename trace_entries to buffer_size_kb Impact: rename of debugfs file trace_entries to buffer_size_kb The original ftrace had fixed size entries, and the number of entries was shown and modified via the file called trace_entries. By converting to the unified trace buffer, we now allow for variable size entries which makes the meaning of trace_entries pointless. Since trace_size might be confused to the size of the trace, this patch names it "buffer_size_kb" (thanks to Arjan van de Ven for this idea). [ mingo@elte.hu: changed from buffer_size to buffer_size_kb ] ( Note, the units are still bytes - the next patch changes that, to keep the wide rename patch separate from the unit-change patch. ) Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4bf070b..b42d420 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3198,11 +3198,11 @@ static __init int tracer_init_debugfs(void) pr_warning("Could not create debugfs " "'trace_pipe' entry\n"); - entry = debugfs_create_file("trace_entries", 0644, d_tracer, + entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer, &global_trace, &tracing_entries_fops); if (!entry) pr_warning("Could not create debugfs " - "'trace_entries' entry\n"); + "'buffer_size_kb' entry\n"); entry = debugfs_create_file("trace_marker", 0220, d_tracer, NULL, &tracing_mark_fops); -- cgit v1.1 From 1696b2b0f44a8d42f3e6b1ea90c21790871c04d9 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 13 Nov 2008 00:09:35 -0500 Subject: ftrace: show buffer size in kilobytes Impact: change the units of buffer_size_kb to kilobytes This patch changes the units of the buffer_size_kb file to kilobytes. Reading and writing to the file uses kilobytes as units. To help users to know what units are used, the output of the file now looks like: # cat /debug/tracing/buffer_size_kb 1408 Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b42d420..d664aae 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2905,7 +2905,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf, char buf[64]; int r; - r = sprintf(buf, "%lu\n", tr->entries); + r = sprintf(buf, "%lu\n", tr->entries >> 10); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } @@ -2945,6 +2945,9 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, atomic_inc(&max_tr.data[cpu]->disabled); } + /* value is in KB */ + val <<= 10; + if (val != global_trace.entries) { ret = ring_buffer_resize(global_trace.buffer, val); if (ret < 0) { -- cgit v1.1 From ee6bce52276c0717ed3e63296e5d9465d339e923 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 17:52:37 -0500 Subject: ftrace: rename iter_ctrl to trace_options Impact: rename file /debug/tracing/iter_ctrl to /debug/tracing/trace_options The original ftrace had a file called "iter_ctrl" that would control the way the output was iterated. But this file grew into a catch all for different trace options. This patch renames the file from iter_ctrl to trace_options to reflect this change. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d664aae..240423a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -204,7 +204,7 @@ static DEFINE_MUTEX(trace_types_lock); /* trace_wait is a waitqueue for tasks blocked on trace_poll */ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); -/* trace_flags holds iter_ctrl options */ +/* trace_flags holds trace_options default values */ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK; /** @@ -2411,7 +2411,7 @@ static struct file_operations tracing_cpumask_fops = { }; static ssize_t -tracing_iter_ctrl_read(struct file *filp, char __user *ubuf, +tracing_trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char *buf; @@ -2448,7 +2448,7 @@ tracing_iter_ctrl_read(struct file *filp, char __user *ubuf, } static ssize_t -tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf, +tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; @@ -2493,8 +2493,8 @@ tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf, static struct file_operations tracing_iter_fops = { .open = tracing_open_generic, - .read = tracing_iter_ctrl_read, - .write = tracing_iter_ctrl_write, + .read = tracing_trace_options_read, + .write = tracing_trace_options_write, }; static const char readme_msg[] = @@ -2508,9 +2508,9 @@ static const char readme_msg[] = "# echo sched_switch > /debug/tracing/current_tracer\n" "# cat /debug/tracing/current_tracer\n" "sched_switch\n" - "# cat /debug/tracing/iter_ctrl\n" + "# cat /debug/tracing/trace_options\n" "noprint-parent nosym-offset nosym-addr noverbose\n" - "# echo print-parent > /debug/tracing/iter_ctrl\n" + "# echo print-parent > /debug/tracing/trace_options\n" "# echo 1 > /debug/tracing/tracing_enabled\n" "# cat /debug/tracing/trace > /tmp/trace.txt\n" "echo 0 > /debug/tracing/tracing_enabled\n" @@ -3148,10 +3148,10 @@ static __init int tracer_init_debugfs(void) if (!entry) pr_warning("Could not create debugfs 'tracing_enabled' entry\n"); - entry = debugfs_create_file("iter_ctrl", 0644, d_tracer, + entry = debugfs_create_file("trace_options", 0644, d_tracer, NULL, &tracing_iter_fops); if (!entry) - pr_warning("Could not create debugfs 'iter_ctrl' entry\n"); + pr_warning("Could not create debugfs 'trace_options' entry\n"); entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer, NULL, &tracing_cpumask_fops); -- cgit v1.1 From 12ef7d448613ead2babd41c3ebfa1fe03c20edef Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 12 Nov 2008 17:52:38 -0500 Subject: ftrace: CPU buffer start annotation clean ups Impact: better handling of CPU buffer start annotation Because of the confusion with the per CPU buffers wrapping where one CPU might be more active at the end of the trace than the other CPUs causing that one CPU to have a shorter history. Kernel developers were confused by the "missing" data of that one CPU at the beginning of the trace output. An annotation was added to the trace output to show that the buffer had started: # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | ##### CPU 3 buffer started #### -0 [003] 158.192959: smp_apic_timer_interrupt [...] -0 [003] 161.556520: default_idle ##### CPU 1 buffer started #### -0 [001] 161.592494: hrtimer_force_reprogram [etc] But this annotation gets a bit messy when tracers do not fill the buffers. This patch does a couple of things: One) it adds a flag to trace_options to disable these annotations Two) it does not annotate if the tracer did not overflow its buffer. This makes the output much cleaner. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 16 +++++++++++++++- kernel/trace/trace.h | 1 + 2 files changed, 16 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 240423a..4a90462 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -205,7 +205,8 @@ static DEFINE_MUTEX(trace_types_lock); static DECLARE_WAIT_QUEUE_HEAD(trace_wait); /* trace_flags holds trace_options default values */ -unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK; +unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | + TRACE_ITER_ANNOTATE; /** * trace_wake_up - wake up tasks waiting for trace input @@ -261,6 +262,7 @@ static const char *trace_options[] = { #ifdef CONFIG_BRANCH_TRACER "branch", #endif + "annotate", NULL }; @@ -1113,6 +1115,7 @@ void tracing_stop_function_trace(void) enum trace_file_type { TRACE_FILE_LAT_FMT = 1, + TRACE_FILE_ANNOTATE = 2, }; static void trace_iterator_increment(struct trace_iterator *iter, int cpu) @@ -1532,6 +1535,12 @@ static void test_cpu_buff_start(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; + if (!(trace_flags & TRACE_ITER_ANNOTATE)) + return; + + if (!(iter->iter_flags & TRACE_FILE_ANNOTATE)) + return; + if (cpu_isset(iter->cpu, iter->started)) return; @@ -2132,6 +2141,11 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) iter->trace = current_trace; iter->pos = -1; + /* Annotate start of buffers if we had overruns */ + if (ring_buffer_overruns(iter->tr->buffer)) + iter->iter_flags |= TRACE_FILE_ANNOTATE; + + for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9e015f5..790ea8c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -473,6 +473,7 @@ enum trace_iterator_flags { #ifdef CONFIG_BRANCH_TRACER TRACE_ITER_BRANCH = 0x1000, #endif + TRACE_ITER_ANNOTATE = 0x2000, }; /* -- cgit v1.1 From b3535c6390f27d04273e4eee0bc687f171fbf5f4 Mon Sep 17 00:00:00 2001 From: walimis Date: Fri, 14 Nov 2008 00:21:02 +0800 Subject: ftrace: remove unnecessary if condition of __unregister_ftrace_function Because it has goto out before ftrace_list == &ftrace_list_end, that's to say, we never meet this condition. Signed-off-by: walimis Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index beb21a5..54cb9a7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -179,8 +179,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (ftrace_enabled) { /* If we only have one func left, then call that directly */ - if (ftrace_list == &ftrace_list_end || - ftrace_list->next == &ftrace_list_end) + if (ftrace_list->next == &ftrace_list_end) ftrace_trace_function = ftrace_list->func; } -- cgit v1.1 From f3c7ac40a99f4044b843e6e2c4f46ab2d354c563 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 14 Nov 2008 16:21:19 -0800 Subject: ftrace: remove condition from ftrace_record_ip Impact: let module functions be recorded when dyn ftrace not enabled When dynamic ftrace had a daemon and a hash to record the locations of mcount callers at run time, the recording needed to stop when ftrace was disabled. But now that the recording is done at compile time and the ftrace_record_ip is only called at boot up and when a module is loaded, we no longer need to check if ftrace_enabled is set. In fact, this breaks module load if it is not set because we skip over module functions. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 54cb9a7..3160254 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -334,7 +334,7 @@ ftrace_record_ip(unsigned long ip) { struct dyn_ftrace *rec; - if (!ftrace_enabled || ftrace_disabled) + if (ftrace_disabled) return NULL; rec = ftrace_alloc_dyn_node(ip); -- cgit v1.1 From b17e8a37a13d0e87165054714434534bb7e69f2d Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 14 Nov 2008 16:21:19 -0800 Subject: ftrace: disable ftrace on anomalies in trace start and stop Impact: robust feature to disable ftrace on start or stop tracing on error Currently only the initial conversion to nops will disable ftrace on an anomaly. But if an anomaly happens on start or stopping of the tracer, it will silently fail. This patch adds a check there too, to disable ftrace and warn if the conversion fails. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 81 ++++++++++++++++++++++++++++----------------------- 1 file changed, 44 insertions(+), 37 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3160254..d5bd21f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -348,6 +348,47 @@ ftrace_record_ip(unsigned long ip) return rec; } +static void print_ip_ins(const char *fmt, unsigned char *p) +{ + int i; + + printk(KERN_CONT "%s", fmt); + + for (i = 0; i < MCOUNT_INSN_SIZE; i++) + printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); +} + +static void ftrace_bug(int failed, unsigned long ip, + unsigned char *expected, + unsigned char *replace) +{ + switch (failed) { + case -EFAULT: + FTRACE_WARN_ON_ONCE(1); + pr_info("ftrace faulted on modifying "); + print_ip_sym(ip); + break; + case -EINVAL: + FTRACE_WARN_ON_ONCE(1); + pr_info("ftrace failed to modify "); + print_ip_sym(ip); + print_ip_ins(" expected: ", expected); + print_ip_ins(" actual: ", (unsigned char *)ip); + print_ip_ins(" replace: ", replace); + printk(KERN_CONT "\n"); + break; + case -EPERM: + FTRACE_WARN_ON_ONCE(1); + pr_info("ftrace faulted on writing "); + print_ip_sym(ip); + break; + default: + FTRACE_WARN_ON_ONCE(1); + pr_info("ftrace faulted on unknown error "); + print_ip_sym(ip); + } +} + #define FTRACE_ADDR ((long)(ftrace_caller)) static int @@ -465,22 +506,13 @@ static void ftrace_replace_code(int enable) if ((system_state == SYSTEM_BOOTING) || !core_kernel_text(rec->ip)) { ftrace_free_rec(rec); - } + } else + ftrace_bug(failed, rec->ip, old, new); } } } } -static void print_ip_ins(const char *fmt, unsigned char *p) -{ - int i; - - printk(KERN_CONT "%s", fmt); - - for (i = 0; i < MCOUNT_INSN_SIZE; i++) - printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); -} - static int ftrace_code_disable(struct dyn_ftrace *rec) { @@ -495,32 +527,7 @@ ftrace_code_disable(struct dyn_ftrace *rec) ret = ftrace_modify_code(ip, call, nop); if (ret) { - switch (ret) { - case -EFAULT: - FTRACE_WARN_ON_ONCE(1); - pr_info("ftrace faulted on modifying "); - print_ip_sym(ip); - break; - case -EINVAL: - FTRACE_WARN_ON_ONCE(1); - pr_info("ftrace failed to modify "); - print_ip_sym(ip); - print_ip_ins(" expected: ", call); - print_ip_ins(" actual: ", (unsigned char *)ip); - print_ip_ins(" replace: ", nop); - printk(KERN_CONT "\n"); - break; - case -EPERM: - FTRACE_WARN_ON_ONCE(1); - pr_info("ftrace faulted on writing "); - print_ip_sym(ip); - break; - default: - FTRACE_WARN_ON_ONCE(1); - pr_info("ftrace faulted on unknown error "); - print_ip_sym(ip); - } - + ftrace_bug(ret, ip, call, nop); rec->flags |= FTRACE_FL_FAILED; return 0; } -- cgit v1.1 From 918c115410c6cc57033835b6a401e57697f9ea4f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 14 Nov 2008 16:21:19 -0800 Subject: ftrace: do not process freed records Impact: keep from converting freed records When the tracer is started or stopped, it converts all code pointed to by the saved records into callers to ftrace or nops. When modules are unloaded, their records are freed, but they still exist within the record pages. This patch changes the code to skip over freed records. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d5bd21f..3940c71 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -488,8 +488,12 @@ static void ftrace_replace_code(int enable) for (i = 0; i < pg->index; i++) { rec = &pg->records[i]; - /* don't modify code that has already faulted */ - if (rec->flags & FTRACE_FL_FAILED) + /* + * Skip over free records and records that have + * failed. + */ + if (rec->flags & FTRACE_FL_FREE || + rec->flags & FTRACE_FL_FAILED) continue; /* ignore updates to this record's mcount site */ -- cgit v1.1 From d51ad7ac48f991c4a8834485727efa99a691cb87 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 15 Nov 2008 15:48:29 -0500 Subject: ftrace: replace raw_local_irq_save with local_irq_save Impact: fix lockdep disabling itself when function tracing is enabled The raw_local_irq_saves used in ftrace is causing problems with lockdep. (it thinks the irq flags are out of sync and disables itself with a warning) The raw ops here are not needed, and the normal local_irq_save is fine. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 4 ++-- kernel/trace/trace_selftest.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4a90462..dff4bee 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1051,7 +1051,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) * Need to use raw, since this must be called before the * recursive protection is performed. */ - raw_local_irq_save(flags); + local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); @@ -1062,7 +1062,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip) } atomic_dec(&data->disabled); - raw_local_irq_restore(flags); + local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_RET_TRACER diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 24e6e07..5cb64ea 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -52,7 +52,7 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) int cpu, ret = 0; /* Don't allow flipping of max traces now */ - raw_local_irq_save(flags); + local_irq_save(flags); __raw_spin_lock(&ftrace_max_lock); cnt = ring_buffer_entries(tr->buffer); @@ -63,7 +63,7 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) break; } __raw_spin_unlock(&ftrace_max_lock); - raw_local_irq_restore(flags); + local_irq_restore(flags); if (count) *count = cnt; -- cgit v1.1 From 31e889098a80ceb3e9e3c555d522b2686a6663c6 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 14 Nov 2008 16:21:19 -0800 Subject: ftrace: pass module struct to arch dynamic ftrace functions Impact: allow archs more flexibility on dynamic ftrace implementations Dynamic ftrace has largly been developed on x86. Since x86 does not have the same limitations as other architectures, the ftrace interaction between the generic code and the architecture specific code was not flexible enough to handle some of the issues that other architectures have. Most notably, module trampolines. Due to the limited branch distance that archs make in calling kernel core code from modules, the module load code must create a trampoline to jump to what will make the larger jump into core kernel code. The problem arises when this happens to a call to mcount. Ftrace checks all code before modifying it and makes sure the current code is what it expects. Right now, there is not enough information to handle modifying module trampolines. This patch changes the API between generic dynamic ftrace code and the arch dependent code. There is now two functions for modifying code: ftrace_make_nop(mod, rec, addr) - convert the code at rec->ip into a nop, where the original text is calling addr. (mod is the module struct if called by module init) ftrace_make_caller(rec, addr) - convert the code rec->ip that should be a nop into a caller to addr. The record "rec" now has a new field called "arch" where the architecture can add any special attributes to each call site record. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/module.c | 2 +- kernel/trace/ftrace.c | 62 ++++++++++++++++++++------------------------------- 2 files changed, 25 insertions(+), 39 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 1f4cc00..6979127 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2201,7 +2201,7 @@ static noinline struct module *load_module(void __user *umod, /* sechdrs[0].sh_size is always zero */ mseg = section_objs(hdr, sechdrs, secstrings, "__mcount_loc", sizeof(*mseg), &num_mcount); - ftrace_init_module(mseg, mseg + num_mcount); + ftrace_init_module(mod, mseg, mseg + num_mcount); err = module_finalize(hdr, sechdrs, mod); if (err < 0) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3940c71..e9a5fbf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -358,9 +358,7 @@ static void print_ip_ins(const char *fmt, unsigned char *p) printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); } -static void ftrace_bug(int failed, unsigned long ip, - unsigned char *expected, - unsigned char *replace) +static void ftrace_bug(int failed, unsigned long ip) { switch (failed) { case -EFAULT: @@ -372,9 +370,7 @@ static void ftrace_bug(int failed, unsigned long ip, FTRACE_WARN_ON_ONCE(1); pr_info("ftrace failed to modify "); print_ip_sym(ip); - print_ip_ins(" expected: ", expected); print_ip_ins(" actual: ", (unsigned char *)ip); - print_ip_ins(" replace: ", replace); printk(KERN_CONT "\n"); break; case -EPERM: @@ -392,8 +388,7 @@ static void ftrace_bug(int failed, unsigned long ip, #define FTRACE_ADDR ((long)(ftrace_caller)) static int -__ftrace_replace_code(struct dyn_ftrace *rec, - unsigned char *old, unsigned char *new, int enable) +__ftrace_replace_code(struct dyn_ftrace *rec, int enable) { unsigned long ip, fl; @@ -435,12 +430,10 @@ __ftrace_replace_code(struct dyn_ftrace *rec, * otherwise enable it! */ if (fl & FTRACE_FL_ENABLED) { - /* swap new and old */ - new = old; - old = ftrace_call_replace(ip, FTRACE_ADDR); + enable = 0; rec->flags &= ~FTRACE_FL_ENABLED; } else { - new = ftrace_call_replace(ip, FTRACE_ADDR); + enable = 1; rec->flags |= FTRACE_FL_ENABLED; } } else { @@ -453,10 +446,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED); if (fl == FTRACE_FL_NOTRACE) return 0; - - new = ftrace_call_replace(ip, FTRACE_ADDR); - } else - old = ftrace_call_replace(ip, FTRACE_ADDR); + } if (enable) { if (rec->flags & FTRACE_FL_ENABLED) @@ -469,21 +459,18 @@ __ftrace_replace_code(struct dyn_ftrace *rec, } } - return ftrace_modify_code(ip, old, new); + if (enable) + return ftrace_make_call(rec, FTRACE_ADDR); + else + return ftrace_make_nop(NULL, rec, FTRACE_ADDR); } static void ftrace_replace_code(int enable) { int i, failed; - unsigned char *new = NULL, *old = NULL; struct dyn_ftrace *rec; struct ftrace_page *pg; - if (enable) - old = ftrace_nop_replace(); - else - new = ftrace_nop_replace(); - for (pg = ftrace_pages_start; pg; pg = pg->next) { for (i = 0; i < pg->index; i++) { rec = &pg->records[i]; @@ -504,34 +491,30 @@ static void ftrace_replace_code(int enable) unfreeze_record(rec); } - failed = __ftrace_replace_code(rec, old, new, enable); + failed = __ftrace_replace_code(rec, enable); if (failed && (rec->flags & FTRACE_FL_CONVERTED)) { rec->flags |= FTRACE_FL_FAILED; if ((system_state == SYSTEM_BOOTING) || !core_kernel_text(rec->ip)) { ftrace_free_rec(rec); } else - ftrace_bug(failed, rec->ip, old, new); + ftrace_bug(failed, rec->ip); } } } } static int -ftrace_code_disable(struct dyn_ftrace *rec) +ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) { unsigned long ip; - unsigned char *nop, *call; int ret; ip = rec->ip; - nop = ftrace_nop_replace(); - call = ftrace_call_replace(ip, mcount_addr); - - ret = ftrace_modify_code(ip, call, nop); + ret = ftrace_make_nop(mod, rec, mcount_addr); if (ret) { - ftrace_bug(ret, ip, call, nop); + ftrace_bug(ret, ip); rec->flags |= FTRACE_FL_FAILED; return 0; } @@ -650,7 +633,7 @@ static cycle_t ftrace_update_time; static unsigned long ftrace_update_cnt; unsigned long ftrace_update_tot_cnt; -static int ftrace_update_code(void) +static int ftrace_update_code(struct module *mod) { struct dyn_ftrace *p, *t; cycle_t start, stop; @@ -667,7 +650,7 @@ static int ftrace_update_code(void) list_del_init(&p->list); /* convert record (i.e, patch mcount-call with NOP) */ - if (ftrace_code_disable(p)) { + if (ftrace_code_disable(mod, p)) { p->flags |= FTRACE_FL_CONVERTED; ftrace_update_cnt++; } else @@ -1309,7 +1292,8 @@ static __init int ftrace_init_debugfs(void) fs_initcall(ftrace_init_debugfs); -static int ftrace_convert_nops(unsigned long *start, +static int ftrace_convert_nops(struct module *mod, + unsigned long *start, unsigned long *end) { unsigned long *p; @@ -1325,18 +1309,19 @@ static int ftrace_convert_nops(unsigned long *start, /* disable interrupts to prevent kstop machine */ local_irq_save(flags); - ftrace_update_code(); + ftrace_update_code(mod); local_irq_restore(flags); mutex_unlock(&ftrace_start_lock); return 0; } -void ftrace_init_module(unsigned long *start, unsigned long *end) +void ftrace_init_module(struct module *mod, + unsigned long *start, unsigned long *end) { if (ftrace_disabled || start == end) return; - ftrace_convert_nops(start, end); + ftrace_convert_nops(mod, start, end); } extern unsigned long __start_mcount_loc[]; @@ -1366,7 +1351,8 @@ void __init ftrace_init(void) last_ftrace_enabled = ftrace_enabled = 1; - ret = ftrace_convert_nops(__start_mcount_loc, + ret = ftrace_convert_nops(NULL, + __start_mcount_loc, __stop_mcount_loc); return; -- cgit v1.1 From 20e5227e9f55ae1969934821ccbf581563785bbe Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 14 Nov 2008 16:21:19 -0800 Subject: ftrace: allow NULL pointers in mcount_loc Impact: make ftrace_convert_nops() more permissive Due to the way different architecture linkers combine the data sections of the mcount_loc (the section that lists all the locations that call mcount), there may be zeros added in that section. This is usually due to strange alignments that the linker performs, that pads in zeros. This patch makes the conversion code to nops skip any pointer in the mcount_loc section that is NULL. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index e9a5fbf..cc42191 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1304,6 +1304,14 @@ static int ftrace_convert_nops(struct module *mod, p = start; while (p < end) { addr = ftrace_call_adjust(*p++); + /* + * Some architecture linkers will pad between + * the different mcount_loc sections of different + * object files to satisfy alignments. + * Skip any NULL pointers. + */ + if (!addr) + continue; ftrace_record_ip(addr); } -- cgit v1.1 From 982c350b9ec4b3564d67f3627a274ae61bbc7e95 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 15 Nov 2008 16:31:41 -0500 Subject: ftrace: fix dyn ftrace filter Impact: correct implementation of dyn ftrace filter The old decisions made by the filter algorithm was complex and incorrect. This lead to inconsistent enabling or disabling of functions when the filter was used. This patch simplifies that code and in doing so, corrects the usage of the filters. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 83 ++++++++++++++++++++++----------------------------- 1 file changed, 36 insertions(+), 47 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index cc42191..b9f2e22 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -394,72 +394,62 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) ip = rec->ip; - if (ftrace_filtered && enable) { + /* + * If this record is not to be traced and + * it is not enabled then do nothing. + * + * If this record is not to be traced and + * it is enabled then disabled it. + * + */ + if (rec->flags & FTRACE_FL_NOTRACE) { + if (rec->flags & FTRACE_FL_ENABLED) + rec->flags &= ~FTRACE_FL_ENABLED; + else + return 0; + + } else if (ftrace_filtered && enable) { /* - * If filtering is on: - * - * If this record is set to be filtered and - * is enabled then do nothing. - * - * If this record is set to be filtered and - * it is not enabled, enable it. - * - * If this record is not set to be filtered - * and it is not enabled do nothing. - * - * If this record is set not to trace then - * do nothing. - * - * If this record is set not to trace and - * it is enabled then disable it. - * - * If this record is not set to be filtered and - * it is enabled, disable it. + * Filtering is on: */ - fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE | - FTRACE_FL_ENABLED); + fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED); - if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) || - (fl == (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) || - !fl || (fl == FTRACE_FL_NOTRACE)) + /* Record is filtered and enabled, do nothing */ + if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) return 0; - /* - * If it is enabled disable it, - * otherwise enable it! - */ - if (fl & FTRACE_FL_ENABLED) { - enable = 0; + /* Record is not filtered and is not enabled do nothing */ + if (!fl) + return 0; + + /* Record is not filtered but enabled, disable it */ + if (fl == FTRACE_FL_ENABLED) rec->flags &= ~FTRACE_FL_ENABLED; - } else { - enable = 1; + else + /* Otherwise record is filtered but not enabled, enable it */ rec->flags |= FTRACE_FL_ENABLED; - } } else { + /* Disable or not filtered */ if (enable) { - /* - * If this record is set not to trace and is - * not enabled, do nothing. - */ - fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED); - if (fl == FTRACE_FL_NOTRACE) - return 0; - } - - if (enable) { + /* if record is enabled, do nothing */ if (rec->flags & FTRACE_FL_ENABLED) return 0; + rec->flags |= FTRACE_FL_ENABLED; + } else { + + /* if record is not enabled do nothing */ if (!(rec->flags & FTRACE_FL_ENABLED)) return 0; + rec->flags &= ~FTRACE_FL_ENABLED; } } - if (enable) + if (rec->flags & FTRACE_FL_ENABLED) return ftrace_make_call(rec, FTRACE_ADDR); else return ftrace_make_nop(NULL, rec, FTRACE_ADDR); @@ -554,8 +544,7 @@ static void ftrace_startup(void) mutex_lock(&ftrace_start_lock); ftrace_start_up++; - if (ftrace_start_up == 1) - command |= FTRACE_ENABLE_CALLS; + command |= FTRACE_ENABLE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; -- cgit v1.1 From ee02a2e5c88ca2e4d6921f08d037b46d5bf82641 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 15 Nov 2008 16:31:41 -0500 Subject: ftrace: make filtered functions effective on setting Impact: set filtered functions at time the filter is set It can be confusing when the set_filter_functions is set (or cleared) and the functions being recorded by the dynamic tracer does not match. This patch causes the code to be updated if the function tracer is enabled and the filter is changed. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b9f2e22..b42ec1d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1194,7 +1194,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) mutex_lock(&ftrace_sysctl_lock); mutex_lock(&ftrace_start_lock); - if (iter->filtered && ftrace_start_up && ftrace_enabled) + if (ftrace_start_up && ftrace_enabled) ftrace_run_update_code(FTRACE_ENABLE_CALLS); mutex_unlock(&ftrace_start_lock); mutex_unlock(&ftrace_sysctl_lock); -- cgit v1.1 From e6e7a65aabdb696cf05a56cfd495c49a11fd4cde Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Nov 2008 05:53:19 +0100 Subject: tracing/ftrace: fix unexpected -EINVAL when longest tracer name is set Impact: fix confusing write() -EINVAL when changing the tracer The following commit d9e540762f5cdd89f24e518ad1fd31142d0b9726 remade alive the bug which made the set of a new tracer returning -EINVAL if this is the longest name of tracer. This patch corrects it. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dff4bee..80898f4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2655,6 +2655,9 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, char buf[max_tracer_type_len+1]; int i; size_t ret; + int err; + + ret = cnt; if (cnt > max_tracer_type_len) cnt = max_tracer_type_len; @@ -2668,12 +2671,11 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) buf[i] = 0; - ret = tracing_set_tracer(buf); - if (!ret) - ret = cnt; + err = tracing_set_tracer(buf); + if (err) + return err; - if (ret > 0) - filp->f_pos += ret; + filp->f_pos += ret; return ret; } -- cgit v1.1 From 1c80025a49855b12fa09bb6db71820e3367b1369 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Nov 2008 05:57:26 +0100 Subject: tracing/ftrace: change the type of the init() callback Impact: extend the ->init() method with the ability to fail This bring a way to know if the initialization of a tracer successed. A tracer must return 0 on success and a traditional error (ie: -ENOMEM) if it fails. If a tracer fails to init, it is free to print a detailed warn. The tracing api will not and switch to a new tracer will just return the error from the init callback. Note: this will be used for the return tracer. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 7 ++-- kernel/trace/trace.h | 3 +- kernel/trace/trace_boot.c | 3 +- kernel/trace/trace_branch.c | 3 +- kernel/trace/trace_functions.c | 3 +- kernel/trace/trace_functions_return.c | 3 +- kernel/trace/trace_irqsoff.c | 9 +++-- kernel/trace/trace_mmiotrace.c | 3 +- kernel/trace/trace_nop.c | 3 +- kernel/trace/trace_sched_switch.c | 3 +- kernel/trace/trace_sched_wakeup.c | 3 +- kernel/trace/trace_selftest.c | 66 ++++++++++++++++++++++++++++++----- kernel/trace/trace_sysprof.c | 3 +- 13 files changed, 88 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 80898f4..396fda0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2638,8 +2638,11 @@ static int tracing_set_tracer(char *buf) current_trace->reset(tr); current_trace = t; - if (t->init) - t->init(tr); + if (t->init) { + ret = t->init(tr); + if (ret) + goto out; + } trace_branch_enable(tr); out: diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 790ea8c..cdbd5cc 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -264,7 +264,8 @@ enum print_line_t { */ struct tracer { const char *name; - void (*init)(struct trace_array *tr); + /* Your tracer should raise a warning if init fails */ + int (*init)(struct trace_array *tr); void (*reset)(struct trace_array *tr); void (*start)(struct trace_array *tr); void (*stop)(struct trace_array *tr); diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index cb333b7..a4fa2c5 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -47,7 +47,7 @@ static void reset_boot_trace(struct trace_array *tr) tracing_reset(tr, cpu); } -static void boot_trace_init(struct trace_array *tr) +static int boot_trace_init(struct trace_array *tr) { int cpu; boot_trace = tr; @@ -56,6 +56,7 @@ static void boot_trace_init(struct trace_array *tr) tracing_reset(tr, cpu); tracing_sched_switch_assign_trace(tr); + return 0; } static enum print_line_t diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 8526555..44bd395 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -125,7 +125,7 @@ static void stop_branch_trace(struct trace_array *tr) disable_branch_tracing(); } -static void branch_trace_init(struct trace_array *tr) +static int branch_trace_init(struct trace_array *tr) { int cpu; @@ -133,6 +133,7 @@ static void branch_trace_init(struct trace_array *tr) tracing_reset(tr, cpu); start_branch_trace(tr); + return 0; } static void branch_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 8693b7a..e74f6d0 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -42,9 +42,10 @@ static void stop_function_trace(struct trace_array *tr) tracing_stop_cmdline_record(); } -static void function_trace_init(struct trace_array *tr) +static int function_trace_init(struct trace_array *tr) { start_function_trace(tr); + return 0; } static void function_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c index 7680b21..61185f7 100644 --- a/kernel/trace/trace_functions_return.c +++ b/kernel/trace/trace_functions_return.c @@ -24,13 +24,14 @@ static void stop_return_trace(struct trace_array *tr) unregister_ftrace_return(); } -static void return_trace_init(struct trace_array *tr) +static int return_trace_init(struct trace_array *tr) { int cpu; for_each_online_cpu(cpu) tracing_reset(tr, cpu); start_return_trace(tr); + return 0; } static void return_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index d919d4e..7c2e326 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -416,11 +416,12 @@ static void irqsoff_tracer_close(struct trace_iterator *iter) } #ifdef CONFIG_IRQSOFF_TRACER -static void irqsoff_tracer_init(struct trace_array *tr) +static int irqsoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_IRQS_OFF; __irqsoff_tracer_init(tr); + return 0; } static struct tracer irqsoff_tracer __read_mostly = { @@ -442,11 +443,12 @@ static struct tracer irqsoff_tracer __read_mostly = #endif #ifdef CONFIG_PREEMPT_TRACER -static void preemptoff_tracer_init(struct trace_array *tr) +static int preemptoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_PREEMPT_OFF; __irqsoff_tracer_init(tr); + return 0; } static struct tracer preemptoff_tracer __read_mostly = @@ -471,11 +473,12 @@ static struct tracer preemptoff_tracer __read_mostly = #if defined(CONFIG_IRQSOFF_TRACER) && \ defined(CONFIG_PREEMPT_TRACER) -static void preemptirqsoff_tracer_init(struct trace_array *tr) +static int preemptirqsoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; __irqsoff_tracer_init(tr); + return 0; } static struct tracer preemptirqsoff_tracer __read_mostly = diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index 51bcf37..433d650 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -30,13 +30,14 @@ static void mmio_reset_data(struct trace_array *tr) tracing_reset(tr, cpu); } -static void mmio_trace_init(struct trace_array *tr) +static int mmio_trace_init(struct trace_array *tr) { pr_debug("in %s\n", __func__); mmio_trace_array = tr; mmio_reset_data(tr); enable_mmiotrace(); + return 0; } static void mmio_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index 2ef1d22..0e77415 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -24,7 +24,7 @@ static void stop_nop_trace(struct trace_array *tr) /* Nothing to do! */ } -static void nop_trace_init(struct trace_array *tr) +static int nop_trace_init(struct trace_array *tr) { int cpu; ctx_trace = tr; @@ -33,6 +33,7 @@ static void nop_trace_init(struct trace_array *tr) tracing_reset(tr, cpu); start_nop_trace(tr); + return 0; } static void nop_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index be35bdf..8633905 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -206,10 +206,11 @@ static void stop_sched_trace(struct trace_array *tr) tracing_stop_sched_switch_record(); } -static void sched_switch_trace_init(struct trace_array *tr) +static int sched_switch_trace_init(struct trace_array *tr) { ctx_trace = tr; start_sched_trace(tr); + return 0; } static void sched_switch_trace_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 983f2b1..0067b49 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -331,10 +331,11 @@ static void stop_wakeup_tracer(struct trace_array *tr) unregister_trace_sched_wakeup(probe_wakeup); } -static void wakeup_tracer_init(struct trace_array *tr) +static int wakeup_tracer_init(struct trace_array *tr) { wakeup_trace = tr; start_wakeup_tracer(tr); + return 0; } static void wakeup_tracer_reset(struct trace_array *tr) diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 5cb64ea..88c8eb7 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -71,6 +71,11 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) return ret; } +static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret) +{ + printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n", + trace->name, init_ret); +} #ifdef CONFIG_FUNCTION_TRACER #ifdef CONFIG_DYNAMIC_FTRACE @@ -111,7 +116,11 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, ftrace_set_filter(func_name, strlen(func_name), 1); /* enable tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + goto out; + } /* Sleep for a 1/10 of a second */ msleep(100); @@ -181,7 +190,12 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) ftrace_enabled = 1; tracer_enabled = 1; - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + goto out; + } + /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ @@ -223,7 +237,12 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return ret; + } + /* reset the max latency */ tracing_max_latency = 0; /* disable interrupts for a bit */ @@ -272,7 +291,12 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) } /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return ret; + } + /* reset the max latency */ tracing_max_latency = 0; /* disable preemption for a bit */ @@ -321,7 +345,11 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * } /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + goto out; + } /* reset the max latency */ tracing_max_latency = 0; @@ -449,7 +477,12 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) wait_for_completion(&isrt); /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return ret; + } + /* reset the max latency */ tracing_max_latency = 0; @@ -505,7 +538,12 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr int ret; /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return ret; + } + /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ @@ -532,7 +570,12 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return 0; + } + /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ @@ -554,7 +597,12 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr) int ret; /* start the tracing */ - trace->init(tr); + ret = trace->init(tr); + if (ret) { + warn_failed_init_tracer(trace, ret); + return ret; + } + /* Sleep for a 1/10 of a second */ msleep(100); /* stop the tracing. */ diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c index 05f7534..54960ed 100644 --- a/kernel/trace/trace_sysprof.c +++ b/kernel/trace/trace_sysprof.c @@ -261,11 +261,12 @@ static void stop_stack_trace(struct trace_array *tr) mutex_unlock(&sample_timer_lock); } -static void stack_trace_init(struct trace_array *tr) +static int stack_trace_init(struct trace_array *tr) { sysprof_trace = tr; start_stack_trace(tr); + return 0; } static void stack_trace_reset(struct trace_array *tr) -- cgit v1.1 From 072b40a15616fe6bea68466e6bffcfcbf5c8f26f Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Nov 2008 05:59:52 +0100 Subject: tracing/branch-tracer: fix a trace recursion on branch tracer Impact: fix crash when enabling the branch-tracer When the branch tracer inserts an event through probe_likely_condition(), it calls local_irq_save() and then results in a trace recursion. local_irq_save() -> trace_hardirqs_off() -> trace_hardirqs_off_caller() -> unlikely() The trace_branch.c file is protected by DISABLE_BRANCH_PROFILING but that doesn't prevent from external call to functions that use unlikely(). My box crashed each time I tried to set this tracer (sudden and hard reboot). Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/trace_branch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 8526555..2511e32 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -41,7 +41,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) if (unlikely(!tr)) return; - local_irq_save(flags); + raw_local_irq_save(flags); cpu = raw_smp_processor_id(); if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) goto out; @@ -73,7 +73,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) out: atomic_dec(&tr->data[cpu]->disabled); - local_irq_restore(flags); + raw_local_irq_restore(flags); } static inline -- cgit v1.1 From e7d3737ea1b102030f44e96c97754101e41515f0 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Nov 2008 06:02:06 +0100 Subject: tracing/function-return-tracer: support for dynamic ftrace on function return tracer This patch adds the support for dynamic tracing on the function return tracer. The whole difference with normal dynamic function tracing is that we don't need to hook on a particular callback. The only pro that we want is to nop or set dynamically the calls to ftrace_caller (which is ftrace_return_caller here). Some security checks ensure that we are not trying to launch dynamic tracing for return tracing while normal function tracing is already running. An example of trace with getnstimeofday set as a filter: ktime_get_ts+0x22/0x50 -> getnstimeofday (2283 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1396 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1825 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1426 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1524 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1434 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1502 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1404 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1397 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1051 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1314 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1344 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1163 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1390 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1374 ns) Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 1 - kernel/trace/ftrace.c | 58 ++++++++++++++++++++++++++++++++--- kernel/trace/trace_functions_return.c | 15 ++------- 3 files changed, 55 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 9c89526..b8378fa 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -59,7 +59,6 @@ config FUNCTION_TRACER config FUNCTION_RET_TRACER bool "Kernel Function return Tracer" - depends on !DYNAMIC_FTRACE depends on HAVE_FUNCTION_RET_TRACER depends on FUNCTION_TRACER help diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b42ec1d..2f78a45 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -50,6 +50,9 @@ static int last_ftrace_enabled; /* Quick disabling of function tracer. */ int function_trace_stop; +/* By default, current tracing type is normal tracing. */ +enum ftrace_tracing_type_t ftrace_tracing_type = FTRACE_TYPE_ENTER; + /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. @@ -385,12 +388,21 @@ static void ftrace_bug(int failed, unsigned long ip) } } -#define FTRACE_ADDR ((long)(ftrace_caller)) static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { unsigned long ip, fl; + unsigned long ftrace_addr; + +#ifdef CONFIG_FUNCTION_RET_TRACER + if (ftrace_tracing_type == FTRACE_TYPE_ENTER) + ftrace_addr = (unsigned long)ftrace_caller; + else + ftrace_addr = (unsigned long)ftrace_return_caller; +#else + ftrace_addr = (unsigned long)ftrace_caller; +#endif ip = rec->ip; @@ -450,9 +462,9 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) } if (rec->flags & FTRACE_FL_ENABLED) - return ftrace_make_call(rec, FTRACE_ADDR); + return ftrace_make_call(rec, ftrace_addr); else - return ftrace_make_nop(NULL, rec, FTRACE_ADDR); + return ftrace_make_nop(NULL, rec, ftrace_addr); } static void ftrace_replace_code(int enable) @@ -1405,10 +1417,17 @@ int register_ftrace_function(struct ftrace_ops *ops) return -1; mutex_lock(&ftrace_sysctl_lock); + + if (ftrace_tracing_type == FTRACE_TYPE_RETURN) { + ret = -EBUSY; + goto out; + } + ret = __register_ftrace_function(ops); ftrace_startup(); - mutex_unlock(&ftrace_sysctl_lock); +out: + mutex_unlock(&ftrace_sysctl_lock); return ret; } @@ -1474,16 +1493,45 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, } #ifdef CONFIG_FUNCTION_RET_TRACER + +/* The callback that hooks the return of a function */ trace_function_return_t ftrace_function_return = (trace_function_return_t)ftrace_stub; -void register_ftrace_return(trace_function_return_t func) + +int register_ftrace_return(trace_function_return_t func) { + int ret = 0; + + mutex_lock(&ftrace_sysctl_lock); + + /* + * Don't launch return tracing if normal function + * tracing is already running. + */ + if (ftrace_trace_function != ftrace_stub) { + ret = -EBUSY; + goto out; + } + + ftrace_tracing_type = FTRACE_TYPE_RETURN; ftrace_function_return = func; + ftrace_startup(); + +out: + mutex_unlock(&ftrace_sysctl_lock); + return ret; } void unregister_ftrace_return(void) { + mutex_lock(&ftrace_sysctl_lock); + ftrace_function_return = (trace_function_return_t)ftrace_stub; + ftrace_shutdown(); + /* Restore normal tracing type */ + ftrace_tracing_type = FTRACE_TYPE_ENTER; + + mutex_unlock(&ftrace_sysctl_lock); } #endif diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c index 61185f7..a68564a 100644 --- a/kernel/trace/trace_functions_return.c +++ b/kernel/trace/trace_functions_return.c @@ -14,29 +14,18 @@ #include "trace.h" -static void start_return_trace(struct trace_array *tr) -{ - register_ftrace_return(&trace_function_return); -} - -static void stop_return_trace(struct trace_array *tr) -{ - unregister_ftrace_return(); -} - static int return_trace_init(struct trace_array *tr) { int cpu; for_each_online_cpu(cpu) tracing_reset(tr, cpu); - start_return_trace(tr); - return 0; + return register_ftrace_return(&trace_function_return); } static void return_trace_reset(struct trace_array *tr) { - stop_return_trace(tr); + unregister_ftrace_return(); } -- cgit v1.1 From 2bdba316c989da028a59becf7516c6350ce3c173 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:35 -0500 Subject: markers: fix unregister Impact: fix marker registers/unregister race get_marker() can return a NULL entry because the mutex is released in the middle of those functions. Make sure we check to see if it has been concurrently removed. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 2898b64..de683a7 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -653,10 +653,11 @@ int marker_probe_register(const char *name, const char *format, goto end; } mutex_unlock(&markers_mutex); - marker_update_probes(); /* may update entry */ + marker_update_probes(); mutex_lock(&markers_mutex); entry = get_marker(name); - WARN_ON(!entry); + if (!entry) + goto end; if (entry->rcu_pending) rcu_barrier_sched(); entry->oldptr = old; @@ -697,7 +698,7 @@ int marker_probe_unregister(const char *name, rcu_barrier_sched(); old = marker_entry_remove_probe(entry, probe, probe_private); mutex_unlock(&markers_mutex); - marker_update_probes(); /* may update entry */ + marker_update_probes(); mutex_lock(&markers_mutex); entry = get_marker(name); if (!entry) @@ -778,10 +779,11 @@ int marker_probe_unregister_private_data(marker_probe_func *probe, rcu_barrier_sched(); old = marker_entry_remove_probe(entry, NULL, probe_private); mutex_unlock(&markers_mutex); - marker_update_probes(); /* may update entry */ + marker_update_probes(); mutex_lock(&markers_mutex); entry = get_marker_from_private_data(probe, probe_private); - WARN_ON(!entry); + if (!entry) + goto end; if (entry->rcu_pending) rcu_barrier_sched(); entry->oldptr = old; -- cgit v1.1 From 021aeb057fc48af03fe5f37d3dda366c0d97aaf3 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:37 -0500 Subject: markers: use rcu_*_sched_notrace and notrace Make marker critical code use notrace to make sure they can be used as an ftrace callback. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index de683a7..22cd7ba 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -81,7 +81,7 @@ struct marker_entry { * though the function pointer change and the marker enabling are two distinct * operations that modifies the execution flow of preemptible code. */ -void __mark_empty_function(void *probe_private, void *call_private, +notrace void __mark_empty_function(void *probe_private, void *call_private, const char *fmt, va_list *args) { } @@ -97,7 +97,8 @@ EXPORT_SYMBOL_GPL(__mark_empty_function); * need to put a full smp_rmb() in this branch. This is why we do not use * rcu_dereference() for the pointer read. */ -void marker_probe_cb(const struct marker *mdata, void *call_private, ...) +notrace void marker_probe_cb(const struct marker *mdata, + void *call_private, ...) { va_list args; char ptype; @@ -107,7 +108,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...) * sure the teardown of the callbacks can be done correctly when they * are in modules and they insure RCU read coherency. */ - rcu_read_lock_sched(); + rcu_read_lock_sched_notrace(); ptype = mdata->ptype; if (likely(!ptype)) { marker_probe_func *func; @@ -145,7 +146,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...) va_end(args); } } - rcu_read_unlock_sched(); + rcu_read_unlock_sched_notrace(); } EXPORT_SYMBOL_GPL(marker_probe_cb); @@ -157,12 +158,13 @@ EXPORT_SYMBOL_GPL(marker_probe_cb); * * Should be connected to markers "MARK_NOARGS". */ -static void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...) +static notrace void marker_probe_cb_noarg(const struct marker *mdata, + void *call_private, ...) { va_list args; /* not initialized */ char ptype; - rcu_read_lock_sched(); + rcu_read_lock_sched_notrace(); ptype = mdata->ptype; if (likely(!ptype)) { marker_probe_func *func; @@ -195,7 +197,7 @@ static void marker_probe_cb_noarg(const struct marker *mdata, void *call_private multi[i].func(multi[i].probe_private, call_private, mdata->format, &args); } - rcu_read_unlock_sched(); + rcu_read_unlock_sched_notrace(); } static void free_old_closure(struct rcu_head *head) -- cgit v1.1 From a419246ac7c2d9282dfd843103702895bb3f3fd7 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:38 -0500 Subject: markers: use module notifier Impact: cleanup Use module notifiers instead of adding a hook in module.c. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 29 +++++++++++++++++++++++++++++ kernel/module.c | 4 ---- 2 files changed, 29 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 22cd7ba..348e70c 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -846,3 +846,32 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe, return ERR_PTR(-ENOENT); } EXPORT_SYMBOL_GPL(marker_get_private_data); + +int marker_module_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct module *mod = data; + + switch (val) { + case MODULE_STATE_COMING: + marker_update_probe_range(mod->markers, + mod->markers + mod->num_markers); + break; + case MODULE_STATE_GOING: + marker_update_probe_range(mod->markers, + mod->markers + mod->num_markers); + break; + } + return 0; +} + +struct notifier_block marker_module_nb = { + .notifier_call = marker_module_notify, + .priority = 0, +}; + +static int init_markers(void) +{ + return register_module_notifier(&marker_module_nb); +} +__initcall(init_markers); diff --git a/kernel/module.c b/kernel/module.c index 1f4cc00..72c6ca5 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2184,10 +2184,6 @@ static noinline struct module *load_module(void __user *umod, struct mod_debug *debug; unsigned int num_debug; -#ifdef CONFIG_MARKERS - marker_update_probe_range(mod->markers, - mod->markers + mod->num_markers); -#endif debug = section_objs(hdr, sechdrs, secstrings, "__verbose", sizeof(*debug), &num_debug); dynamic_printk_setup(debug, num_debug); -- cgit v1.1 From c1df1bd2c4d4b20c83755a0f41956b57aec4842a Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:39 -0500 Subject: markers: auto enable tracepoints (new API : trace_mark_tp()) Impact: new API Add a new API trace_mark_tp(), which declares a marker within a tracepoint probe. When the marker is activated, the tracepoint is automatically enabled. No branch test is used at the marker site, because it would be a duplicate of the branch already present in the tracepoint. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/marker.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index 348e70c..c14ec26 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -479,7 +479,7 @@ static int marker_set_format(struct marker_entry *entry, const char *format) static int set_marker(struct marker_entry *entry, struct marker *elem, int active) { - int ret; + int ret = 0; WARN_ON(strcmp(entry->name, elem->name) != 0); if (entry->format) { @@ -531,9 +531,40 @@ static int set_marker(struct marker_entry *entry, struct marker *elem, */ smp_wmb(); elem->ptype = entry->ptype; + + if (elem->tp_name && (active ^ elem->state)) { + WARN_ON(!elem->tp_cb); + /* + * It is ok to directly call the probe registration because type + * checking has been done in the __trace_mark_tp() macro. + */ + + if (active) { + /* + * try_module_get should always succeed because we hold + * lock_module() to get the tp_cb address. + */ + ret = try_module_get(__module_text_address( + (unsigned long)elem->tp_cb)); + BUG_ON(!ret); + ret = tracepoint_probe_register_noupdate( + elem->tp_name, + elem->tp_cb); + } else { + ret = tracepoint_probe_unregister_noupdate( + elem->tp_name, + elem->tp_cb); + /* + * tracepoint_probe_update_all() must be called + * before the module containing tp_cb is unloaded. + */ + module_put(__module_text_address( + (unsigned long)elem->tp_cb)); + } + } elem->state = active; - return 0; + return ret; } /* @@ -544,7 +575,24 @@ static int set_marker(struct marker_entry *entry, struct marker *elem, */ static void disable_marker(struct marker *elem) { + int ret; + /* leave "call" as is. It is known statically. */ + if (elem->tp_name && elem->state) { + WARN_ON(!elem->tp_cb); + /* + * It is ok to directly call the probe registration because type + * checking has been done in the __trace_mark_tp() macro. + */ + ret = tracepoint_probe_unregister_noupdate(elem->tp_name, + elem->tp_cb); + WARN_ON(ret); + /* + * tracepoint_probe_update_all() must be called + * before the module containing tp_cb is unloaded. + */ + module_put(__module_text_address((unsigned long)elem->tp_cb)); + } elem->state = 0; elem->single.func = __mark_empty_function; /* Update the function before setting the ptype */ @@ -608,6 +656,7 @@ static void marker_update_probes(void) marker_update_probe_range(__start___markers, __stop___markers); /* Markers in modules. */ module_update_markers(); + tracepoint_probe_update_all(); } /** -- cgit v1.1 From de0baf9ad661ac630a45a50ea1717cc4f4b33ace Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:42 -0500 Subject: tracepoints: fix disable Impact: fix race Set the probe array pointer to NULL when the tracepoint is disabled. The probe array point not being NULL could generate a race condition where the reader would dereference a freed pointer. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/tracepoint.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index e96590f..47a7303 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -262,6 +262,7 @@ static void set_tracepoint(struct tracepoint_entry **entry, static void disable_tracepoint(struct tracepoint *elem) { elem->state = 0; + rcu_assign_pointer(elem->funcs, NULL); } /** -- cgit v1.1 From 32f85742778dfc2c74975cf0b9f5bdb13470cb32 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:46 -0500 Subject: tracepoints: use modules notifiers Impact: cleanup Use module notifiers for tracepoint updates rather than adding a hook in module.c. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/module.c | 5 ----- kernel/tracepoint.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 72c6ca5..fc1dff9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2187,11 +2187,6 @@ static noinline struct module *load_module(void __user *umod, debug = section_objs(hdr, sechdrs, secstrings, "__verbose", sizeof(*debug), &num_debug); dynamic_printk_setup(debug, num_debug); - -#ifdef CONFIG_TRACEPOINTS - tracepoint_update_probe_range(mod->tracepoints, - mod->tracepoints + mod->num_tracepoints); -#endif } /* sechdrs[0].sh_size is always zero */ diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 47a7303..94ac4e3 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -541,3 +541,32 @@ void tracepoint_iter_reset(struct tracepoint_iter *iter) iter->tracepoint = NULL; } EXPORT_SYMBOL_GPL(tracepoint_iter_reset); + +int tracepoint_module_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct module *mod = data; + + switch (val) { + case MODULE_STATE_COMING: + tracepoint_update_probe_range(mod->tracepoints, + mod->tracepoints + mod->num_tracepoints); + break; + case MODULE_STATE_GOING: + tracepoint_update_probe_range(mod->tracepoints, + mod->tracepoints + mod->num_tracepoints); + break; + } + return 0; +} + +struct notifier_block tracepoint_module_nb = { + .notifier_call = tracepoint_module_notify, + .priority = 0, +}; + +static int init_tracepoints(void) +{ + return register_module_notifier(&tracepoint_module_nb); +} +__initcall(init_tracepoints); -- cgit v1.1 From 7e066fb870fcd1025ec3ba7bbde5d541094f4ce1 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 14 Nov 2008 17:47:47 -0500 Subject: tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() Impact: API *CHANGE*. Must update all tracepoint users. Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint structure in a single spot for all the kernel. It helps reducing memory consumption, especially when declaring a lot of tracepoints, e.g. for kmalloc tracing. *API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for tracepoint declarations rather than DEFINE_TRACE(). This is the sane way to do it. The name previously used was misleading. Updates scheduler instrumentation to follow this API change. Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar --- kernel/exit.c | 4 ++++ kernel/fork.c | 2 ++ kernel/kthread.c | 3 +++ kernel/sched.c | 6 ++++++ kernel/signal.c | 2 ++ 5 files changed, 17 insertions(+) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index ae2b92b..f995d24 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -54,6 +54,10 @@ #include #include +DEFINE_TRACE(sched_process_free); +DEFINE_TRACE(sched_process_exit); +DEFINE_TRACE(sched_process_wait); + static void exit_mm(struct task_struct * tsk); static inline int task_detached(struct task_struct *p) diff --git a/kernel/fork.c b/kernel/fork.c index f608356..0837d0d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -79,6 +79,8 @@ DEFINE_PER_CPU(unsigned long, process_counts) = 0; __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ +DEFINE_TRACE(sched_process_fork); + int nr_processes(void) { int cpu; diff --git a/kernel/kthread.c b/kernel/kthread.c index 8e7a7ce..4fbc456 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -21,6 +21,9 @@ static DEFINE_SPINLOCK(kthread_create_lock); static LIST_HEAD(kthread_create_list); struct task_struct *kthreadd_task; +DEFINE_TRACE(sched_kthread_stop); +DEFINE_TRACE(sched_kthread_stop_ret); + struct kthread_create_info { /* Information passed to kthread() from kthreadd. */ diff --git a/kernel/sched.c b/kernel/sched.c index 50a21f9..327f91c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -118,6 +118,12 @@ */ #define RUNTIME_INF ((u64)~0ULL) +DEFINE_TRACE(sched_wait_task); +DEFINE_TRACE(sched_wakeup); +DEFINE_TRACE(sched_wakeup_new); +DEFINE_TRACE(sched_switch); +DEFINE_TRACE(sched_migrate_task); + #ifdef CONFIG_SMP /* * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) diff --git a/kernel/signal.c b/kernel/signal.c index 4530fc6..e9afe63 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -41,6 +41,8 @@ static struct kmem_cache *sigqueue_cachep; +DEFINE_TRACE(sched_signal_send); + static void __user *sig_handler(struct task_struct *t, int sig) { return t->sighand->action[sig - 1].sa.sa_handler; -- cgit v1.1 From 227a837567e339c74d9d4243d03a29bd943a018c Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 16 Nov 2008 09:50:34 +0100 Subject: markers/tracpoints: fix non-modular build fix: kernel/marker.c: In function 'marker_module_notify': kernel/marker.c:905: error: 'MODULE_STATE_COMING' undeclared (first use in this function) [...] Signed-off-by: Ingo Molnar --- kernel/marker.c | 4 ++++ kernel/tracepoint.c | 4 ++++ 2 files changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/marker.c b/kernel/marker.c index c14ec26..ea54f26 100644 --- a/kernel/marker.c +++ b/kernel/marker.c @@ -896,6 +896,8 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe, } EXPORT_SYMBOL_GPL(marker_get_private_data); +#ifdef CONFIG_MODULES + int marker_module_notify(struct notifier_block *self, unsigned long val, void *data) { @@ -924,3 +926,5 @@ static int init_markers(void) return register_module_notifier(&marker_module_nb); } __initcall(init_markers); + +#endif /* CONFIG_MODULES */ diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 94ac4e3..7960274 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -542,6 +542,8 @@ void tracepoint_iter_reset(struct tracepoint_iter *iter) } EXPORT_SYMBOL_GPL(tracepoint_iter_reset); +#ifdef CONFIG_MODULES + int tracepoint_module_notify(struct notifier_block *self, unsigned long val, void *data) { @@ -570,3 +572,5 @@ static int init_tracepoints(void) return register_module_notifier(&tracepoint_module_nb); } __initcall(init_tracepoints); + +#endif /* CONFIG_MODULES */ -- cgit v1.1 From 0c726da983de0704254250ef6495ca152e7abcca Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sun, 16 Nov 2008 16:07:58 +0530 Subject: tracing: branch tracer, fix writing to trace/trace_options Impact: fix trace_options behavior writing to trace/trace_options use the index of the array to find the value of the flag. With branch tracer flag defined conditionally, this breaks writing to trace_options with branch tracer disabled. Signed-off-by: Aneesh Kumar K.V Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 2 -- kernel/trace/trace.h | 2 -- 2 files changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4a90462..b04923b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -259,9 +259,7 @@ static const char *trace_options[] = { "sched-tree", "ftrace_printk", "ftrace_preempt", -#ifdef CONFIG_BRANCH_TRACER "branch", -#endif "annotate", NULL }; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 790ea8c..b41d7b4 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -470,9 +470,7 @@ enum trace_iterator_flags { TRACE_ITER_SCHED_TREE = 0x200, TRACE_ITER_PRINTK = 0x400, TRACE_ITER_PREEMPTONLY = 0x800, -#ifdef CONFIG_BRANCH_TRACER TRACE_ITER_BRANCH = 0x1000, -#endif TRACE_ITER_ANNOTATE = 0x2000, }; -- cgit v1.1 From 74fcd524e808975dd546dac847119f1995a7c622 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 17 Nov 2008 15:39:52 +0100 Subject: account_steal_time: kill the unneeded account_group_system_time() Impact: remove unnecessary accounting call I don't actually understand account_steal_time() and I failed to find the commit which added account_group_system_time(), but this looks bogus. In any case rq->idle must be single-threaded, so it can't have ->totals. Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index c94baf2..b388c9b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4202,7 +4202,6 @@ void account_steal_time(struct task_struct *p, cputime_t steal) if (p == rq->idle) { p->stime = cputime_add(p->stime, steal); - account_group_system_time(p, steal); if (atomic_read(&rq->nr_iowait) > 0) cpustat->iowait = cputime64_add(cpustat->iowait, tmp); else -- cgit v1.1 From ce394471d13bf071939a9a0b48c64c297676d233 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 17 Nov 2008 15:40:01 +0100 Subject: thread_group_cputime: kill the bogus ->signal != NULL check Impact: simplify the code thread_group_cputime() is called by current when it must have the valid ->signal, or under ->siglock, or under tasklist_lock after the ->signal check, or the caller is wait_task_zombie() which reaps the child. In any case ->signal can't be NULL. But the point of this patch is not optimization. If it is possible to call thread_group_cputime() when ->signal == NULL we are doing something wrong, and we should not mask the problem. thread_group_cputime() fills *times and the caller will use it, if we silently use task_struct->*times* we report the wrong values. Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- kernel/posix-cpu-timers.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 895337b..3f4377e 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -58,21 +58,21 @@ void thread_group_cputime( struct task_struct *tsk, struct task_cputime *times) { - struct signal_struct *sig; + struct task_cputime *totals, *tot; int i; - struct task_cputime *tot; - sig = tsk->signal; - if (unlikely(!sig) || !sig->cputime.totals) { + totals = tsk->signal->cputime.totals; + if (!totals) { times->utime = tsk->utime; times->stime = tsk->stime; times->sum_exec_runtime = tsk->se.sum_exec_runtime; return; } + times->stime = times->utime = cputime_zero; times->sum_exec_runtime = 0; for_each_possible_cpu(i) { - tot = per_cpu_ptr(tsk->signal->cputime.totals, i); + tot = per_cpu_ptr(totals, i); times->utime = cputime_add(times->utime, tot->utime); times->stime = cputime_add(times->stime, tot->stime); times->sum_exec_runtime += tot->sum_exec_runtime; -- cgit v1.1 From 2b5fe6de58276d0b5a7c884d5dbfc300ca47db78 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 17 Nov 2008 15:40:08 +0100 Subject: thread_group_cputime: move a couple of callsites outside of ->siglock Impact: relax the locking of cpu-time accounting calls ->siglock buys nothing for thread_group_cputime() in do_sys_times() and wait_task_zombie() (which btw takes the unrelated parent's ->siglock). Actually I think do_sys_times() doesn't need ->siglock at all. Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- kernel/exit.c | 2 +- kernel/sys.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index ae2b92b..b9c4d8b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1330,10 +1330,10 @@ static int wait_task_zombie(struct task_struct *p, int options, * group, which consolidates times for all threads in the * group including the group leader. */ + thread_group_cputime(p, &cputime); spin_lock_irq(&p->parent->sighand->siglock); psig = p->parent->signal; sig = p->signal; - thread_group_cputime(p, &cputime); psig->cutime = cputime_add(psig->cutime, cputime_add(cputime.utime, diff --git a/kernel/sys.c b/kernel/sys.c index 31deba8..5fc3a0c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -858,8 +858,8 @@ void do_sys_times(struct tms *tms) struct task_cputime cputime; cputime_t cutime, cstime; - spin_lock_irq(¤t->sighand->siglock); thread_group_cputime(current, &cputime); + spin_lock_irq(¤t->sighand->siglock); cutime = current->signal->cutime; cstime = current->signal->cstime; spin_unlock_irq(¤t->sighand->siglock); -- cgit v1.1 From adf9f19574334c9a29a2bc956009fcac7edf1a6b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 17 Nov 2008 19:23:42 +0100 Subject: tracing/ftrace: implement a set_flag callback for tracers Impact: give a way to send specific messages to tracers The current implementation of tracing uses some flags to control the output of general tracers. But we have no way to implement custom flags handling for a specific tracer. This patch proposes a new callback for the struct tracer which called set_flag and a structure that represents a 32 bits variable flag. A tracer can implement a struct tracer_flags on which it puts the initial value of the flag integer. Than it can place a range of flags with their name and their flag mask on the flag integer. The structure that implement a single flag is called struct tracer_opt. These custom flags will be available through the trace_options file like the general tracing flags. Changing their value is done like the other general flags. For example if you have a flag that calls "foo", you can activate it by writing "foo" or "nofoo" on trace_options. Note that the set_flag callback is optional and is only needed if you want the flags changing to be signaled to your tracer and let it to accept or refuse their assignment. V2: Some arrangements in coding style.... Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++---- kernel/trace/trace.h | 26 +++++++++++++++ 2 files changed, 112 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2596b5a..9531fdd 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -43,6 +43,20 @@ unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX; unsigned long __read_mostly tracing_thresh; +/* For tracers that don't implement custom flags */ +static struct tracer_opt dummy_tracer_opt[] = { + { } +}; + +static struct tracer_flags dummy_tracer_flags = { + .val = 0, + .opts = dummy_tracer_opt +}; + +static int dummy_set_flag(u32 old_flags, u32 bit, int set) +{ + return 0; +} /* * Kill all tracing for good (never come back). @@ -529,6 +543,14 @@ int register_tracer(struct tracer *type) } } + if (!type->set_flag) + type->set_flag = &dummy_set_flag; + if (!type->flags) + type->flags = &dummy_tracer_flags; + else + if (!type->flags->opts) + type->flags->opts = dummy_tracer_opt; + #ifdef CONFIG_FTRACE_STARTUP_TEST if (type->selftest) { struct tracer *saved_tracer = current_trace; @@ -2426,10 +2448,13 @@ static ssize_t tracing_trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { + int i; char *buf; int r = 0; int len = 0; - int i; + u32 tracer_flags = current_trace->flags->val; + struct tracer_opt *trace_opts = current_trace->flags->opts; + /* calulate max size */ for (i = 0; trace_options[i]; i++) { @@ -2437,6 +2462,15 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf, len += 3; /* "no" and space */ } + /* + * Increase the size with names of options specific + * of the current tracer. + */ + for (i = 0; trace_opts[i].name; i++) { + len += strlen(trace_opts[i].name); + len += 3; /* "no" and space */ + } + /* +2 for \n and \0 */ buf = kmalloc(len + 2, GFP_KERNEL); if (!buf) @@ -2449,6 +2483,15 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf, r += sprintf(buf + r, "no%s ", trace_options[i]); } + for (i = 0; trace_opts[i].name; i++) { + if (tracer_flags & trace_opts[i].bit) + r += sprintf(buf + r, "%s ", + trace_opts[i].name); + else + r += sprintf(buf + r, "no%s ", + trace_opts[i].name); + } + r += sprintf(buf + r, "\n"); WARN_ON(r >= len + 2); @@ -2459,6 +2502,40 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf, return r; } +/* Try to assign a tracer specific option */ +static int set_tracer_option(struct tracer *trace, char *cmp, int neg) +{ + struct tracer_flags *trace_flags = trace->flags; + struct tracer_opt *opts = NULL; + int ret = 0, i = 0; + int len; + + for (i = 0; trace_flags->opts[i].name; i++) { + opts = &trace_flags->opts[i]; + len = strlen(opts->name); + + if (strncmp(cmp, opts->name, len) == 0) { + ret = trace->set_flag(trace_flags->val, + opts->bit, !neg); + break; + } + } + /* Not found */ + if (!trace_flags->opts[i].name) + return -EINVAL; + + /* Refused to handle */ + if (ret) + return ret; + + if (neg) + trace_flags->val &= ~opts->bit; + else + trace_flags->val |= opts->bit; + + return 0; +} + static ssize_t tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -2466,6 +2543,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, char buf[64]; char *cmp = buf; int neg = 0; + int ret; int i; if (cnt >= sizeof(buf)) @@ -2492,11 +2570,13 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, break; } } - /* - * If no option could be set, return an error: - */ - if (!trace_options[i]) - return -EINVAL; + + /* If no option could be set, test the specific tracer options */ + if (!trace_options[i]) { + ret = set_tracer_option(current_trace, cmp, neg); + if (ret) + return ret; + } filp->f_pos += cnt; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 37947f6..9d22618 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -259,6 +259,29 @@ enum print_line_t { TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */ }; + +/* + * An option specific to a tracer. This is a boolean value. + * The bit is the bit index that sets its value on the + * flags value in struct tracer_flags. + */ +struct tracer_opt { + const char *name; /* Will appear on the trace_options file */ + u32 bit; /* Mask assigned in val field in tracer_flags */ +}; + +/* + * The set of specific options for a tracer. Your tracer + * have to set the initial value of the flags val. + */ +struct tracer_flags { + u32 val; + struct tracer_opt *opts; +}; + +/* Makes more easy to define a tracer opt */ +#define TRACER_OPT(s, b) .name = #s, .bit = b + /* * A specific tracer, represented by methods that operate on a trace array: */ @@ -280,8 +303,11 @@ struct tracer { struct trace_array *tr); #endif enum print_line_t (*print_line)(struct trace_iterator *iter); + /* If you handled the flag setting, return 0 */ + int (*set_flag)(u32 old_flags, u32 bit, int set); struct tracer *next; int print_max; + struct tracer_flags *flags; }; struct trace_seq { -- cgit v1.1 From 0619faf657806b943e6acf51f60f1cd023a96c78 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 17 Nov 2008 19:26:30 +0100 Subject: tracing/ftrace: make nop tracer using tracer flags Impact: give an example on how to use specific tracer flags This patch propose to use the nop tracer to provide an example for using the tracer's custom flags implementation. V2: replace structures and defines just after the headers includes for cleanliness. V3: replace defines by enum values. Signed-off-by: Frederic Weisbecker Acked-by: Steven Noonan Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_nop.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index 0e77415..b9767ac 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -12,6 +12,27 @@ #include "trace.h" +/* Our two options */ +enum { + TRACE_NOP_OPT_ACCEPT = 0x1, + TRACE_NOP_OPT_REFUSE = 0x2 +}; + +/* Options for the tracer (see trace_options file) */ +static struct tracer_opt nop_opts[] = { + /* Option that will be accepted by set_flag callback */ + { TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) }, + /* Option that will be refused by set_flag callback */ + { TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) }, + { } /* Always set a last empty entry */ +}; + +static struct tracer_flags nop_flags = { + /* You can check your flags value here when you want. */ + .val = 0, /* By default: all flags disabled */ + .opts = nop_opts +}; + static struct trace_array *ctx_trace; static void start_nop_trace(struct trace_array *tr) @@ -41,6 +62,35 @@ static void nop_trace_reset(struct trace_array *tr) stop_nop_trace(tr); } +/* It only serves as a signal handler and a callback to + * accept or refuse tthe setting of a flag. + * If you don't implement it, then the flag setting will be + * automatically accepted. + */ +static int nop_set_flag(u32 old_flags, u32 bit, int set) +{ + /* + * Note that you don't need to update nop_flags.val yourself. + * The tracing Api will do it automatically if you return 0 + */ + if (bit == TRACE_NOP_OPT_ACCEPT) { + printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept." + " Now cat trace_options to see the result\n", + set); + return 0; + } + + if (bit == TRACE_NOP_OPT_REFUSE) { + printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse." + "Now cat trace_options to see the result\n", + set); + return -EINVAL; + } + + return 0; +} + + struct tracer nop_trace __read_mostly = { .name = "nop", @@ -49,5 +99,7 @@ struct tracer nop_trace __read_mostly = #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_nop, #endif + .flags = &nop_flags, + .set_flag = nop_set_flag }; -- cgit v1.1 From 0231022cc32d5f2e7f3c06b75691dda0ad6aec33 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 17 Nov 2008 03:22:41 +0100 Subject: tracing/function-return-tracer: add the overrun field Impact: help to find the better depth of trace We decided to arbitrary define the depth of function return trace as "20". Perhaps this is not enough. To help finding an optimal depth, we measure now the overrun: the number of functions that have been missed for the current thread. By default this is not displayed, we have to do set a particular flag on the return tracer: echo overrun > /debug/tracing/trace_options And the overrun will be printed on the right. As the trace shows below, the current 20 depth is not enough. update_wall_time+0x37f/0x8c0 -> update_xtime_cache (345 ns) (Overruns: 2838) update_wall_time+0x384/0x8c0 -> clocksource_get_next (1141 ns) (Overruns: 2838) do_timer+0x23/0x100 -> update_wall_time (3882 ns) (Overruns: 2838) tick_do_update_jiffies64+0xbf/0x160 -> do_timer (5339 ns) (Overruns: 2838) tick_sched_timer+0x6a/0xf0 -> tick_do_update_jiffies64 (7209 ns) (Overruns: 2838) vgacon_set_cursor_size+0x98/0x120 -> native_io_delay (2613 ns) (Overruns: 274) vgacon_cursor+0x16e/0x1d0 -> vgacon_set_cursor_size (33151 ns) (Overruns: 274) set_cursor+0x5f/0x80 -> vgacon_cursor (36432 ns) (Overruns: 274) con_flush_chars+0x34/0x40 -> set_cursor (38790 ns) (Overruns: 274) release_console_sem+0x1ec/0x230 -> up (721 ns) (Overruns: 274) release_console_sem+0x225/0x230 -> wake_up_klogd (316 ns) (Overruns: 274) con_flush_chars+0x39/0x40 -> release_console_sem (2996 ns) (Overruns: 274) con_write+0x22/0x30 -> con_flush_chars (46067 ns) (Overruns: 274) n_tty_write+0x1cc/0x360 -> con_write (292670 ns) (Overruns: 274) smp_apic_timer_interrupt+0x2a/0x90 -> native_apic_mem_write (330 ns) (Overruns: 274) irq_enter+0x17/0x70 -> idle_cpu (413 ns) (Overruns: 274) smp_apic_timer_interrupt+0x2f/0x90 -> irq_enter (1525 ns) (Overruns: 274) ktime_get_ts+0x40/0x70 -> getnstimeofday (465 ns) (Overruns: 274) ktime_get_ts+0x60/0x70 -> set_normalized_timespec (436 ns) (Overruns: 274) ktime_get+0x16/0x30 -> ktime_get_ts (2501 ns) (Overruns: 274) hrtimer_interrupt+0x77/0x1a0 -> ktime_get (3439 ns) (Overruns: 274) Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 1 + kernel/trace/trace.h | 1 + kernel/trace/trace_functions_return.c | 38 +++++++++++++++++++++++++++++------ 3 files changed, 34 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9531fdd..e97c29a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -853,6 +853,7 @@ static void __trace_function_return(struct trace_array *tr, entry->parent_ip = trace->ret; entry->rettime = trace->rettime; entry->calltime = trace->calltime; + entry->overrun = trace->overrun; ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags); } #endif diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9d22618..2cb12fd 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -60,6 +60,7 @@ struct ftrace_ret_entry { unsigned long parent_ip; unsigned long long calltime; unsigned long long rettime; + unsigned long overrun; }; extern struct tracer boot_tracer; diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c index a68564a..e00d645 100644 --- a/kernel/trace/trace_functions_return.c +++ b/kernel/trace/trace_functions_return.c @@ -14,6 +14,19 @@ #include "trace.h" +#define TRACE_RETURN_PRINT_OVERRUN 0x1 +static struct tracer_opt trace_opts[] = { + /* Display overruns or not */ + { TRACER_OPT(overrun, TRACE_RETURN_PRINT_OVERRUN) }, + { } /* Empty entry */ +}; + +static struct tracer_flags tracer_flags = { + .val = 0, /* Don't display overruns by default */ + .opts = trace_opts +}; + + static int return_trace_init(struct trace_array *tr) { int cpu; @@ -42,26 +55,39 @@ print_return_function(struct trace_iterator *iter) ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip); if (!ret) return TRACE_TYPE_PARTIAL_LINE; + ret = seq_print_ip_sym(s, field->ip, trace_flags & TRACE_ITER_SYM_MASK); if (!ret) return TRACE_TYPE_PARTIAL_LINE; - ret = trace_seq_printf(s, " (%llu ns)\n", + + ret = trace_seq_printf(s, " (%llu ns)", field->rettime - field->calltime); if (!ret) return TRACE_TYPE_PARTIAL_LINE; - else - return TRACE_TYPE_HANDLED; + + if (tracer_flags.val & TRACE_RETURN_PRINT_OVERRUN) { + ret = trace_seq_printf(s, " (Overruns: %lu)", + field->overrun); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + } + + ret = trace_seq_printf(s, "\n"); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + + return TRACE_TYPE_HANDLED; } return TRACE_TYPE_UNHANDLED; } -static struct tracer return_trace __read_mostly = -{ +static struct tracer return_trace __read_mostly = { .name = "return", .init = return_trace_init, .reset = return_trace_reset, - .print_line = print_return_function + .print_line = print_return_function, + .flags = &tracer_flags, }; static __init int init_return_trace(void) -- cgit v1.1 From a22506347d038a66506c6f57e9b97104128e280d Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 18 Nov 2008 18:06:35 +0100 Subject: ftrace: preemptoff selftest not working Impact: fix preemptoff and preemptirqsoff tracer self-tests I was wondering why the preemptoff and preemptirqsoff tracer selftests don't work on s390. After all its just that they get called from non-preemptible context: kernel_init() will execute all initcalls, however the first line in kernel_init() is lock_kernel(), which causes the preempt_count to be increased. Any later calls to add_preempt_count() (especially those from the selftests) will therefore not result in a call to trace_preempt_off() since the check below in add_preempt_count() will be false: if (preempt_count() == val) trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); Hence the trace buffer will be empty. Fix this by releasing the BKL during the self-tests. Signed-off-by: Heiko Carstens Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 396fda0..1689212 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -532,6 +532,13 @@ int register_tracer(struct tracer *type) } #ifdef CONFIG_FTRACE_STARTUP_TEST + /* + * When this gets called we hold the BKL which means that preemption + * is disabled. Various trace selftests however need to disable + * and enable preemption for successful tests. So we drop the BKL here + * and grab it after the tests again. + */ + unlock_kernel(); if (type->selftest) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; @@ -562,6 +569,7 @@ int register_tracer(struct tracer *type) } printk(KERN_CONT "PASSED\n"); } + lock_kernel(); #endif type->next = trace_types; -- cgit v1.1 From 86fa2f60674540df0b34f5c547ed0c1cf3a8f212 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 19 Nov 2008 10:00:15 +0100 Subject: ftrace: fix selftest locking Impact: fix self-test boot crash Self-test failure forgot to re-lock the BKL - crashing the next initcall: Testing tracer irqsoff: .. no entries found ..FAILED! initcall init_irqsoff_tracer+0x0/0x11 returned 0 after 3906 usecs calling init_mmio_trace+0x0/0xf @ 1 ------------[ cut here ]------------ Kernel BUG at c0c0a915 [verbose debug info unavailable] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC last sysfs file: Pid: 1, comm: swapper Not tainted (2.6.28-rc5-tip #53704) EIP: 0060:[] EFLAGS: 00010286 CPU: 1 EIP is at unlock_kernel+0x10/0x2b EAX: ffffffff EBX: 00000000 ECX: 00000000 EDX: f7030000 ESI: c12da19c EDI: 00000000 EBP: f7039f54 ESP: f7039f54 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 1, ti=f7038000 task=f7030000 task.ti=f7038000) Stack: f7039f6c c0164d30 c013fed8 a7d8d7b4 00000000 00000000 f7039f74 c12fb78a f7039fd0 c0101132 c12fb77d 00000000 6f727200 6f632072 2d206564 c1002031 0000000f f7039fa2 f7039fb0 3531b171 00000000 00000000 0000002f c12ca480 Call Trace: [] ? register_tracer+0x66/0x13f [] ? ktime_get+0x19/0x1b [] ? init_mmio_trace+0xd/0xf [] ? do_one_initcall+0x4a/0x111 [] ? init_mmio_trace+0x0/0xf [] ? init_irq_proc+0x46/0x59 [] ? kernel_init+0x104/0x152 [] ? kernel_init+0x0/0x152 [] ? kernel_thread_helper+0x7/0x10 Code: 58 14 43 75 0a b8 00 9b 2d c1 e8 51 43 7a ff 64 a1 00 a0 37 c1 89 58 14 5b 5d c3 55 64 8b 15 00 a0 37 c1 83 7a 14 00 89 e5 79 04 <0f> 0b eb fe 8b 42 14 48 85 c0 89 42 14 79 0a b8 00 9b 2d c1 e8 EIP: [] unlock_kernel+0x10/0x2b SS:ESP 0068:f7039f54 ---[ end trace a7919e7f17c0a725 ]--- Kernel panic - not syncing: Attempted to kill init! So clean up the flow a bit. Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1689212..24b6238 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -520,7 +520,15 @@ int register_tracer(struct tracer *type) return -1; } + /* + * When this gets called we hold the BKL which means that + * preemption is disabled. Various trace selftests however + * need to disable and enable preemption for successful tests. + * So we drop the BKL here and grab it after the tests again. + */ + unlock_kernel(); mutex_lock(&trace_types_lock); + for (t = trace_types; t; t = t->next) { if (strcmp(type->name, t->name) == 0) { /* already found */ @@ -532,13 +540,6 @@ int register_tracer(struct tracer *type) } #ifdef CONFIG_FTRACE_STARTUP_TEST - /* - * When this gets called we hold the BKL which means that preemption - * is disabled. Various trace selftests however need to disable - * and enable preemption for successful tests. So we drop the BKL here - * and grab it after the tests again. - */ - unlock_kernel(); if (type->selftest) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; @@ -550,9 +551,9 @@ int register_tracer(struct tracer *type) * internal tracing to verify that everything is in order. * If we fail, we do not register this tracer. */ - for_each_tracing_cpu(i) { + for_each_tracing_cpu(i) tracing_reset(tr, i); - } + current_trace = type; /* the test is responsible for initializing and enabling */ pr_info("Testing tracer %s: ", type->name); @@ -564,12 +565,11 @@ int register_tracer(struct tracer *type) goto out; } /* Only reset on passing, to avoid touching corrupted buffers */ - for_each_tracing_cpu(i) { + for_each_tracing_cpu(i) tracing_reset(tr, i); - } + printk(KERN_CONT "PASSED\n"); } - lock_kernel(); #endif type->next = trace_types; @@ -580,6 +580,7 @@ int register_tracer(struct tracer *type) out: mutex_unlock(&trace_types_lock); + lock_kernel(); return ret; } -- cgit v1.1 From 60a515132086b2c28a8141d873297fdf7a180ca7 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 18 Nov 2008 22:20:10 -0800 Subject: profiling: clean up profile_nop() Impact: cleanup No point in inlining this. Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/profile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/profile.c b/kernel/profile.c index 5b7d1ac..7f93a50 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -544,7 +544,7 @@ static const struct file_operations proc_profile_operations = { }; #ifdef CONFIG_SMP -static inline void profile_nop(void *unused) +static void profile_nop(void *unused) { } -- cgit v1.1 From 522a110b42b306d696cf84e34c677ed0e7080194 Mon Sep 17 00:00:00 2001 From: Liming Wang Date: Fri, 21 Nov 2008 11:00:18 +0800 Subject: function tracing: fix wrong position computing of stack_trace Impact: make output of stack_trace complete if buffer overruns When read buffer overruns, the output of stack_trace isn't complete. When printing records with seq_printf in t_show, if the read buffer has overruned by the current record, then this record won't be printed to user space through read buffer, it will just be dropped in this printing. When next printing, t_start should return the "*pos"th record, which is the one dropped by previous printing, but it just returns (m->private + *pos)th record. Here we use a more sane method to implement seq_operations which can be found in kernel code. Thus we needn't initialize m->private. About testing, it's not easy to overrun read buffer, but we can use seq_printf to print more padding bytes in t_show, then it's easy to check whether or not records are lost. This commit has been tested on both condition of overrun and non overrun. Signed-off-by: Liming Wang Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_stack.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index be682b6..3bdb44b 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -184,11 +184,16 @@ static struct file_operations stack_max_size_fops = { static void * t_next(struct seq_file *m, void *v, loff_t *pos) { - long i = (long)m->private; + long i; (*pos)++; - i++; + if (v == SEQ_START_TOKEN) + i = 0; + else { + i = *(long *)v; + i++; + } if (i >= max_stack_trace.nr_entries || stack_dump_trace[i] == ULONG_MAX) @@ -201,12 +206,15 @@ t_next(struct seq_file *m, void *v, loff_t *pos) static void *t_start(struct seq_file *m, loff_t *pos) { - void *t = &m->private; + void *t = SEQ_START_TOKEN; loff_t l = 0; local_irq_disable(); __raw_spin_lock(&max_stack_lock); + if (*pos == 0) + return SEQ_START_TOKEN; + for (; t && l < *pos; t = t_next(m, t, &l)) ; @@ -235,10 +243,10 @@ static int trace_lookup_stack(struct seq_file *m, long i) static int t_show(struct seq_file *m, void *v) { - long i = *(long *)v; + long i; int size; - if (i < 0) { + if (v == SEQ_START_TOKEN) { seq_printf(m, " Depth Size Location" " (%d entries)\n" " ----- ---- --------\n", @@ -246,6 +254,8 @@ static int t_show(struct seq_file *m, void *v) return 0; } + i = *(long *)v; + if (i >= max_stack_trace.nr_entries || stack_dump_trace[i] == ULONG_MAX) return 0; @@ -275,10 +285,6 @@ static int stack_trace_open(struct inode *inode, struct file *file) int ret; ret = seq_open(file, &stack_trace_seq_ops); - if (!ret) { - struct seq_file *m = file->private_data; - m->private = (void *)-1; - } return ret; } -- cgit v1.1 From b0788caf7af773b6c2374590dabd3a205f0918a8 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 21 Nov 2008 15:57:32 +0800 Subject: lockdep: consistent alignement for lockdep info Impact: prettify /proc/lockdep_info Just feel odd that not all lines of lockdep info are aligned. Signed-off-by: Li Zefan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 06e1571..46a4041 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3276,10 +3276,10 @@ void __init lockdep_info(void) { printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); - printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); + printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); - printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); + printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); -- cgit v1.1 From f201ae2356c74bcae130b2177b3dca903ea98071 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 23 Nov 2008 06:22:56 +0100 Subject: tracing/function-return-tracer: store return stack into task_struct and allocate it dynamically Impact: use deeper function tracing depth safely Some tests showed that function return tracing needed a more deeper depth of function calls. But it could be unsafe to store these return addresses to the stack. So these arrays will now be allocated dynamically into task_struct of current only when the tracer is activated. Typical scheme when tracer is activated: - allocate a return stack for each task in global list. - fork: allocate the return stack for the newly created task - exit: free return stack of current - idle init: same as fork I chose a default depth of 50. I don't have overruns anymore. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/exit.c | 5 ++- kernel/fork.c | 4 +++ kernel/sched.c | 3 ++ kernel/trace/ftrace.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 106 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 35c8ec2..b9d4463 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include @@ -1127,7 +1128,9 @@ NORET_TYPE void do_exit(long code) preempt_disable(); /* causes final put_task_struct in finish_task_switch(). */ tsk->state = TASK_DEAD; - +#ifdef CONFIG_FUNCTION_RET_TRACER + ftrace_retfunc_exit_task(tsk); +#endif schedule(); BUG(); /* Avoid "noreturn function does return". */ diff --git a/kernel/fork.c b/kernel/fork.c index ac62f43..d1eb30e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include #include @@ -1269,6 +1270,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, total_forks++; spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); +#ifdef CONFIG_FUNCTION_RET_TRACER + ftrace_retfunc_init_task(p); +#endif proc_fork_connector(p); cgroup_post_fork(p); return p; diff --git a/kernel/sched.c b/kernel/sched.c index 4de5610..fb17205 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5901,6 +5901,9 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; +#ifdef CONFIG_FUNCTION_RET_TRACER + ftrace_retfunc_init_task(idle); +#endif } /* diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f212da4..90d99fb 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1498,10 +1498,77 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, #ifdef CONFIG_FUNCTION_RET_TRACER +static atomic_t ftrace_retfunc_active; + /* The callback that hooks the return of a function */ trace_function_return_t ftrace_function_return = (trace_function_return_t)ftrace_stub; + +/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ +static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) +{ + int i; + int ret = 0; + unsigned long flags; + int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; + struct task_struct *g, *t; + + for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { + ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH + * sizeof(struct ftrace_ret_stack), + GFP_KERNEL); + if (!ret_stack_list[i]) { + start = 0; + end = i; + ret = -ENOMEM; + goto free; + } + } + + read_lock_irqsave(&tasklist_lock, flags); + do_each_thread(g, t) { + if (start == end) { + ret = -EAGAIN; + goto unlock; + } + + if (t->ret_stack == NULL) { + t->ret_stack = ret_stack_list[start++]; + t->curr_ret_stack = -1; + atomic_set(&t->trace_overrun, 0); + } + } while_each_thread(g, t); + +unlock: + read_unlock_irqrestore(&tasklist_lock, flags); +free: + for (i = start; i < end; i++) + kfree(ret_stack_list[i]); + return ret; +} + +/* Allocate a return stack for each task */ +static int start_return_tracing(void) +{ + struct ftrace_ret_stack **ret_stack_list; + int ret; + + ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * + sizeof(struct ftrace_ret_stack *), + GFP_KERNEL); + + if (!ret_stack_list) + return -ENOMEM; + + do { + ret = alloc_retstack_tasklist(ret_stack_list); + } while (ret == -EAGAIN); + + kfree(ret_stack_list); + return ret; +} + int register_ftrace_return(trace_function_return_t func) { int ret = 0; @@ -1516,7 +1583,12 @@ int register_ftrace_return(trace_function_return_t func) ret = -EBUSY; goto out; } - + atomic_inc(&ftrace_retfunc_active); + ret = start_return_tracing(); + if (ret) { + atomic_dec(&ftrace_retfunc_active); + goto out; + } ftrace_tracing_type = FTRACE_TYPE_RETURN; ftrace_function_return = func; ftrace_startup(); @@ -1530,6 +1602,7 @@ void unregister_ftrace_return(void) { mutex_lock(&ftrace_sysctl_lock); + atomic_dec(&ftrace_retfunc_active); ftrace_function_return = (trace_function_return_t)ftrace_stub; ftrace_shutdown(); /* Restore normal tracing type */ @@ -1537,6 +1610,27 @@ void unregister_ftrace_return(void) mutex_unlock(&ftrace_sysctl_lock); } + +/* Allocate a return stack for newly created task */ +void ftrace_retfunc_init_task(struct task_struct *t) +{ + if (atomic_read(&ftrace_retfunc_active)) { + t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH + * sizeof(struct ftrace_ret_stack), + GFP_KERNEL); + if (!t->ret_stack) + return; + t->curr_ret_stack = -1; + atomic_set(&t->trace_overrun, 0); + } else + t->ret_stack = NULL; +} + +void ftrace_retfunc_exit_task(struct task_struct *t) +{ + kfree(t->ret_stack); + t->ret_stack = NULL; +} #endif -- cgit v1.1 From 82f60f0bc854aada696f27d863c03bef91f1509d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 23 Nov 2008 09:18:56 +0100 Subject: tracing/function-return-tracer: clean up task start/exit callbacks Impact: cleanup Eliminate #ifdefs in core code by using empty inline functions. Signed-off-by: Ingo Molnar --- kernel/exit.c | 2 -- kernel/fork.c | 2 -- kernel/sched.c | 2 -- 3 files changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index b9d4463..ef04d03 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1128,9 +1128,7 @@ NORET_TYPE void do_exit(long code) preempt_disable(); /* causes final put_task_struct in finish_task_switch(). */ tsk->state = TASK_DEAD; -#ifdef CONFIG_FUNCTION_RET_TRACER ftrace_retfunc_exit_task(tsk); -#endif schedule(); BUG(); /* Avoid "noreturn function does return". */ diff --git a/kernel/fork.c b/kernel/fork.c index d1eb30e..fbf4a4c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1270,9 +1270,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, total_forks++; spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); -#ifdef CONFIG_FUNCTION_RET_TRACER ftrace_retfunc_init_task(p); -#endif proc_fork_connector(p); cgroup_post_fork(p); return p; diff --git a/kernel/sched.c b/kernel/sched.c index fb17205..388d9db 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5901,9 +5901,7 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; -#ifdef CONFIG_FUNCTION_RET_TRACER ftrace_retfunc_init_task(idle); -#endif } /* -- cgit v1.1 From 02b67518e2b1c490787dac7f35e1204e74fe21ba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sat, 22 Nov 2008 13:28:47 +0200 Subject: tracing: add support for userspace stacktraces in tracing/iter_ctrl MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: add new (default-off) tracing visualization feature Usage example: mount -t debugfs nodev /sys/kernel/debug cd /sys/kernel/debug/tracing echo userstacktrace >iter_ctrl echo sched_switch >current_tracer echo 1 >tracing_enabled .... run application ... echo 0 >tracing_enabled Then read one of 'trace','latency_trace','trace_pipe'. To get the best output you can compile your userspace programs with frame pointers (at least glibc + the app you are tracing). Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/trace/trace.h | 9 +++++ 2 files changed, 102 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4ee6f03..ced8b4f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -275,6 +275,7 @@ static const char *trace_options[] = { "ftrace_preempt", "branch", "annotate", + "userstacktrace", NULL }; @@ -918,6 +919,44 @@ void __trace_stack(struct trace_array *tr, ftrace_trace_stack(tr, data, flags, skip, preempt_count()); } +static void ftrace_trace_userstack(struct trace_array *tr, + struct trace_array_cpu *data, + unsigned long flags, int pc) +{ + struct userstack_entry *entry; + struct stack_trace trace; + struct ring_buffer_event *event; + unsigned long irq_flags; + + if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) + return; + + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), + &irq_flags); + if (!event) + return; + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, flags, pc); + entry->ent.type = TRACE_USER_STACK; + + memset(&entry->caller, 0, sizeof(entry->caller)); + + trace.nr_entries = 0; + trace.max_entries = FTRACE_STACK_ENTRIES; + trace.skip = 0; + trace.entries = entry->caller; + + save_stack_trace_user(&trace); + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); +} + +void __trace_userstack(struct trace_array *tr, + struct trace_array_cpu *data, + unsigned long flags) +{ + ftrace_trace_userstack(tr, data, flags, preempt_count()); +} + static void ftrace_trace_special(void *__tr, void *__data, unsigned long arg1, unsigned long arg2, unsigned long arg3, @@ -941,6 +980,7 @@ ftrace_trace_special(void *__tr, void *__data, entry->arg3 = arg3; ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, irq_flags, 4, pc); + ftrace_trace_userstack(tr, data, irq_flags, pc); trace_wake_up(); } @@ -979,6 +1019,7 @@ tracing_sched_switch_trace(struct trace_array *tr, entry->next_cpu = task_cpu(next); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, flags, 5, pc); + ftrace_trace_userstack(tr, data, flags, pc); } void @@ -1008,6 +1049,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr, entry->next_cpu = task_cpu(wakee); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, flags, 6, pc); + ftrace_trace_userstack(tr, data, flags, pc); trace_wake_up(); } @@ -1387,6 +1429,31 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags) return ret; } +static int +seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, + unsigned long sym_flags) +{ + int ret = 1; + unsigned i; + + for (i = 0; i < FTRACE_STACK_ENTRIES; i++) { + unsigned long ip = entry->caller[i]; + + if (ip == ULONG_MAX || !ret) + break; + if (i) + ret = trace_seq_puts(s, " <- "); + if (!ip) { + ret = trace_seq_puts(s, "??"); + continue; + } + if (ret /*&& (sym_flags & TRACE_ITER_SYM_ADDR)*/) + ret = trace_seq_printf(s, " <" IP_FMT ">", ip); + } + + return ret; +} + static void print_lat_help_header(struct seq_file *m) { seq_puts(m, "# _------=> CPU# \n"); @@ -1702,6 +1769,16 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) field->line); break; } + case TRACE_USER_STACK: { + struct userstack_entry *field; + + trace_assign_type(field, entry); + + seq_print_userip_objs(field, s, sym_flags); + if (entry->flags & TRACE_FLAG_CONT) + trace_seq_print_cont(s, iter); + break; + } default: trace_seq_printf(s, "Unknown type %d\n", entry->type); } @@ -1853,6 +1930,19 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) field->line); break; } + case TRACE_USER_STACK: { + struct userstack_entry *field; + + trace_assign_type(field, entry); + + ret = seq_print_userip_objs(field, s, sym_flags); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + ret = trace_seq_putc(s, '\n'); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + break; + } } return TRACE_TYPE_HANDLED; } @@ -1912,6 +2002,7 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter) break; } case TRACE_SPECIAL: + case TRACE_USER_STACK: case TRACE_STACK: { struct special_entry *field; @@ -2000,6 +2091,7 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter) break; } case TRACE_SPECIAL: + case TRACE_USER_STACK: case TRACE_STACK: { struct special_entry *field; @@ -2054,6 +2146,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter) break; } case TRACE_SPECIAL: + case TRACE_USER_STACK: case TRACE_STACK: { struct special_entry *field; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 2cb12fd..17bb4c8 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -26,6 +26,7 @@ enum trace_type { TRACE_BOOT_CALL, TRACE_BOOT_RET, TRACE_FN_RET, + TRACE_USER_STACK, __TRACE_LAST_TYPE }; @@ -42,6 +43,7 @@ struct trace_entry { unsigned char flags; unsigned char preempt_count; int pid; + int tgid; }; /* @@ -99,6 +101,11 @@ struct stack_entry { unsigned long caller[FTRACE_STACK_ENTRIES]; }; +struct userstack_entry { + struct trace_entry ent; + unsigned long caller[FTRACE_STACK_ENTRIES]; +}; + /* * ftrace_printk entry: */ @@ -240,6 +247,7 @@ extern void __ftrace_bad_type(void); IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \ IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \ IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \ + IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\ IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \ IF_ASSIGN(var, ent, struct special_entry, 0); \ IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \ @@ -500,6 +508,7 @@ enum trace_iterator_flags { TRACE_ITER_PREEMPTONLY = 0x800, TRACE_ITER_BRANCH = 0x1000, TRACE_ITER_ANNOTATE = 0x2000, + TRACE_ITER_USERSTACKTRACE = 0x4000 }; /* -- cgit v1.1 From b54d3de9f3b8956653b06f1a32e9f9321c6d9027 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sat, 22 Nov 2008 13:28:48 +0200 Subject: tracing: identify which executable object the userspace address belongs to MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: modify+improve the userstacktrace tracing visualization feature Store thread group leader id, and use it to lookup the address in the process's map. We could have looked up the address on thread's map, but the thread might not exist by the time we are called. The process might not exist either, but if you are reading trace_pipe, that is unlikely. Example usage: mount -t debugfs nodev /sys/kernel/debug cd /sys/kernel/debug/tracing echo userstacktrace >iter_ctrl echo sym-userobj >iter_ctrl echo sched_switch >current_tracer echo 1 >tracing_enabled cat trace_pipe >/tmp/trace& .... run application ... echo 0 >tracing_enabled cat /tmp/trace You'll see stack entries like: /lib/libpthread-2.7.so[+0xd370] You can convert them to function/line using: addr2line -fie /lib/libpthread-2.7.so 0xd370 Or: addr2line -fie /usr/lib/debug/libpthread-2.7.so 0xd370 For non-PIC/PIE executables this won't work: a.out[+0x73b] You need to run the following: addr2line -fie a.out 0x40073b (where 0x400000 is the default load address of a.out) Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++----- kernel/trace/trace.h | 3 +- 2 files changed, 81 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ced8b4f..62776b7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -276,6 +277,7 @@ static const char *trace_options[] = { "branch", "annotate", "userstacktrace", + "sym-userobj", NULL }; @@ -422,6 +424,28 @@ trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len) return trace_seq_putmem(s, hex, j); } +static int +trace_seq_path(struct trace_seq *s, struct path *path) +{ + unsigned char *p; + + if (s->len >= (PAGE_SIZE - 1)) + return 0; + p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); + if (!IS_ERR(p)) { + p = mangle_path(s->buffer + s->len, p, "\n"); + if (p) { + s->len = p - s->buffer; + return 1; + } + } else { + s->buffer[s->len++] = '?'; + return 1; + } + + return 0; +} + static void trace_seq_reset(struct trace_seq *s) { @@ -802,6 +826,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, entry->preempt_count = pc & 0xff; entry->pid = (tsk) ? tsk->pid : 0; + entry->tgid = (tsk) ? tsk->tgid : 0; entry->flags = #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) | @@ -1429,28 +1454,73 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags) return ret; } +static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, + unsigned long ip, unsigned long sym_flags) +{ + struct file *file = NULL; + unsigned long vmstart = 0; + int ret = 1; + + if (mm) { + const struct vm_area_struct *vma = find_vma(mm, ip); + if (vma) { + file = vma->vm_file; + vmstart = vma->vm_start; + } + } + if (file) { + ret = trace_seq_path(s, &file->f_path); + if (ret) + ret = trace_seq_printf(s, "[+0x%lx]", + ip - vmstart); + } + if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file)) + ret = trace_seq_printf(s, " <" IP_FMT ">", ip); + return ret; +} + static int seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, - unsigned long sym_flags) + unsigned long sym_flags) { + struct mm_struct *mm = NULL; int ret = 1; unsigned i; + if (trace_flags & TRACE_ITER_SYM_USEROBJ) { + struct task_struct *task; + /* + * we do the lookup on the thread group leader, + * since individual threads might have already quit! + */ + rcu_read_lock(); + task = find_task_by_vpid(entry->ent.tgid); + rcu_read_unlock(); + + if (task) + mm = get_task_mm(task); + } + for (i = 0; i < FTRACE_STACK_ENTRIES; i++) { unsigned long ip = entry->caller[i]; if (ip == ULONG_MAX || !ret) break; - if (i) + if (i && ret) ret = trace_seq_puts(s, " <- "); if (!ip) { - ret = trace_seq_puts(s, "??"); + if (ret) + ret = trace_seq_puts(s, "??"); continue; } - if (ret /*&& (sym_flags & TRACE_ITER_SYM_ADDR)*/) - ret = trace_seq_printf(s, " <" IP_FMT ">", ip); + if (!ret) + break; + if (ret) + ret = seq_print_user_ip(s, mm, ip, sym_flags); } + if (mm) + mmput(mm); return ret; } @@ -1775,8 +1845,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_assign_type(field, entry); seq_print_userip_objs(field, s, sym_flags); - if (entry->flags & TRACE_FLAG_CONT) - trace_seq_print_cont(s, iter); + trace_seq_putc(s, '\n'); break; } default: @@ -3581,6 +3650,9 @@ void ftrace_dump(void) atomic_inc(&global_trace.data[cpu]->disabled); } + /* don't look at user memory in panic mode */ + trace_flags &= ~TRACE_ITER_SYM_USEROBJ; + printk(KERN_TRACE "Dumping ftrace buffer:\n"); iter.tr = &global_trace; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 17bb4c8..28c15c2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -508,7 +508,8 @@ enum trace_iterator_flags { TRACE_ITER_PREEMPTONLY = 0x800, TRACE_ITER_BRANCH = 0x1000, TRACE_ITER_ANNOTATE = 0x2000, - TRACE_ITER_USERSTACKTRACE = 0x4000 + TRACE_ITER_USERSTACKTRACE = 0x4000, + TRACE_ITER_SYM_USEROBJ = 0x8000 }; /* -- cgit v1.1 From cbe2f5a6e84eebb98ab42fc5e58c3cd5b7767349 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 23 Nov 2008 10:37:12 +0100 Subject: tracing: allow tracing of suspend/resume & hibernation code again Impact: widen function-tracing to suspend+resume (and hibernation) sequences Now that the ftrace kernel thread is gone, we can allow tracing during suspend/resume again. So revert these two commits: f42ac38c5 "ftrace: disable tracing for suspend to ram" 41108eb10 "ftrace: disable tracing for hibernation" This should be tested very carefully, as it could interact with altneratives instruction patching, etc. Signed-off-by: Ingo Molnar --- kernel/power/disk.c | 13 +++---------- kernel/power/main.c | 5 +---- 2 files changed, 4 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/power/disk.c b/kernel/power/disk.c index c9d7408..f77d381 100644 --- a/kernel/power/disk.c +++ b/kernel/power/disk.c @@ -22,7 +22,6 @@ #include #include #include -#include #include "power.h" @@ -257,7 +256,7 @@ static int create_image(int platform_mode) int hibernation_snapshot(int platform_mode) { - int error, ftrace_save; + int error; /* Free memory before shutting down devices. */ error = swsusp_shrink_memory(); @@ -269,7 +268,6 @@ int hibernation_snapshot(int platform_mode) goto Close; suspend_console(); - ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_FREEZE); if (error) goto Recover_platform; @@ -299,7 +297,6 @@ int hibernation_snapshot(int platform_mode) Resume_devices: device_resume(in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE); - __ftrace_enabled_restore(ftrace_save); resume_console(); Close: platform_end(platform_mode); @@ -370,11 +367,10 @@ static int resume_target_kernel(void) int hibernation_restore(int platform_mode) { - int error, ftrace_save; + int error; pm_prepare_console(); suspend_console(); - ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_QUIESCE); if (error) goto Finish; @@ -389,7 +385,6 @@ int hibernation_restore(int platform_mode) platform_restore_cleanup(platform_mode); device_resume(PMSG_RECOVER); Finish: - __ftrace_enabled_restore(ftrace_save); resume_console(); pm_restore_console(); return error; @@ -402,7 +397,7 @@ int hibernation_restore(int platform_mode) int hibernation_platform_enter(void) { - int error, ftrace_save; + int error; if (!hibernation_ops) return -ENOSYS; @@ -417,7 +412,6 @@ int hibernation_platform_enter(void) goto Close; suspend_console(); - ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_HIBERNATE); if (error) { if (hibernation_ops->recover) @@ -452,7 +446,6 @@ int hibernation_platform_enter(void) hibernation_ops->finish(); Resume_devices: device_resume(PMSG_RESTORE); - __ftrace_enabled_restore(ftrace_save); resume_console(); Close: hibernation_ops->end(); diff --git a/kernel/power/main.c b/kernel/power/main.c index b8f7ce9..613f169 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -22,7 +22,6 @@ #include #include #include -#include #include "power.h" @@ -317,7 +316,7 @@ static int suspend_enter(suspend_state_t state) */ int suspend_devices_and_enter(suspend_state_t state) { - int error, ftrace_save; + int error; if (!suspend_ops) return -ENOSYS; @@ -328,7 +327,6 @@ int suspend_devices_and_enter(suspend_state_t state) goto Close; } suspend_console(); - ftrace_save = __ftrace_enabled_save(); suspend_test_start(); error = device_suspend(PMSG_SUSPEND); if (error) { @@ -360,7 +358,6 @@ int suspend_devices_and_enter(suspend_state_t state) suspend_test_start(); device_resume(PMSG_RESUME); suspend_test_finish("resume devices"); - __ftrace_enabled_restore(ftrace_save); resume_console(); Close: if (suspend_ops->end) -- cgit v1.1 From 45b797492a0758e64dff74e9db70e1f65e0603a5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 00:40:40 -0500 Subject: trace: consolidate unlikely and likely profiler Impact: clean up to make one profiler of like and unlikely tracer The likely and unlikely profiler prints out the file and line numbers of the annotated branches that it is profiling. It shows the number of times it was correct or incorrect in its guess. Having two different files or sections for that matter to tell us if it was a likely or unlikely is pretty pointless. We really only care if it was correct or not. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 3 +-- kernel/trace/trace_branch.c | 39 +++++++++++++-------------------------- 2 files changed, 14 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index b8378fa..7e35487 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -166,8 +166,7 @@ config TRACE_BRANCH_PROFILING This tracer profiles all the the likely and unlikely macros in the kernel. It will display the results in: - /debugfs/tracing/profile_likely - /debugfs/tracing/profile_unlikely + /debugfs/tracing/profile_annotated_branch Note: this will add a significant overhead, only turn this on if you need to profile the system's use of these macros. diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 23f9b02..21dedc8 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -261,7 +261,7 @@ static struct seq_operations tracing_likely_seq_ops = { .show = t_show, }; -static int tracing_likely_open(struct inode *inode, struct file *file) +static int tracing_branch_open(struct inode *inode, struct file *file) { int ret; @@ -274,25 +274,18 @@ static int tracing_likely_open(struct inode *inode, struct file *file) return ret; } -static struct file_operations tracing_likely_fops = { - .open = tracing_likely_open, +static const struct file_operations tracing_branch_fops = { + .open = tracing_branch_open, .read = seq_read, .llseek = seq_lseek, }; -extern unsigned long __start_likely_profile[]; -extern unsigned long __stop_likely_profile[]; -extern unsigned long __start_unlikely_profile[]; -extern unsigned long __stop_unlikely_profile[]; +extern unsigned long __start_annotated_branch_profile[]; +extern unsigned long __stop_annotated_branch_profile[]; -static struct ftrace_pointer ftrace_likely_pos = { - .start = __start_likely_profile, - .stop = __stop_likely_profile, -}; - -static struct ftrace_pointer ftrace_unlikely_pos = { - .start = __start_unlikely_profile, - .stop = __stop_unlikely_profile, +static const struct ftrace_pointer ftrace_annotated_branch_pos = { + .start = __start_annotated_branch_profile, + .stop = __stop_annotated_branch_profile, }; static __init int ftrace_branch_init(void) @@ -302,18 +295,12 @@ static __init int ftrace_branch_init(void) d_tracer = tracing_init_dentry(); - entry = debugfs_create_file("profile_likely", 0444, d_tracer, - &ftrace_likely_pos, - &tracing_likely_fops); - if (!entry) - pr_warning("Could not create debugfs 'profile_likely' entry\n"); - - entry = debugfs_create_file("profile_unlikely", 0444, d_tracer, - &ftrace_unlikely_pos, - &tracing_likely_fops); + entry = debugfs_create_file("profile_annotated_branch", 0444, d_tracer, + &ftrace_annotated_branch_pos, + &tracing_branch_fops); if (!entry) - pr_warning("Could not create debugfs" - " 'profile_unlikely' entry\n"); + pr_warning("Could not create debugfs " + "'profile_annotatet_branch' entry\n"); return 0; } -- cgit v1.1 From bac28bfe42ba98ee67503f78984d1d5e1ebbbb78 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 01:51:53 -0500 Subject: trace: branch profiling should not print percent without data Impact: cleanup on output of branch profiler When a branch has not been taken, it does not make sense to show a percentage incorrect or hit. This patch changes the behaviour to print out a 'X' when the branch has not been executed yet. For example: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 2096 0 0 do_arch_prctl process_64.c 832 0 0 X do_arch_prctl process_64.c 804 2604 0 0 IS_ERR err.h 34 130228 5765 4 __switch_to process_64.c 673 0 0 X enable_TSC process_64.c 448 0 0 X disable_TSC process_64.c 431 Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_branch.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 21dedc8..142acb3 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -225,7 +225,7 @@ static int t_show(struct seq_file *m, void *v) { struct ftrace_branch_data *p = v; const char *f; - unsigned long percent; + long percent; if (v == (void *)1) { seq_printf(m, " correct incorrect %% " @@ -247,9 +247,13 @@ static int t_show(struct seq_file *m, void *v) percent = p->incorrect * 100; percent /= p->correct + p->incorrect; } else - percent = p->incorrect ? 100 : 0; + percent = p->incorrect ? 100 : -1; - seq_printf(m, "%8lu %8lu %3lu ", p->correct, p->incorrect, percent); + seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect); + if (percent < 0) + seq_printf(m, " X "); + else + seq_printf(m, "%3ld ", percent); seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); return 0; } -- cgit v1.1 From 2bcd521a684cc94befbe2ce7d5b613c841b0d304 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 01:30:54 -0500 Subject: trace: profile all if conditionals Impact: feature to profile if statements This patch adds a branch profiler for all if () statements. The results will be found in: /debugfs/tracing/profile_branch For example: miss hit % Function File Line ------- --------- - -------- ---- ---- 0 1 100 x86_64_start_reservations head64.c 127 0 1 100 copy_bootdata head64.c 69 1 0 0 x86_64_start_kernel head64.c 111 32 0 0 set_intr_gate desc.h 319 1 0 0 reserve_ebda_region head.c 51 1 0 0 reserve_ebda_region head.c 47 0 1 100 reserve_ebda_region head.c 42 0 0 X maxcpus main.c 165 Miss means the branch was not taken. Hit means the branch was taken. The percent is the percentage the branch was taken. This adds a significant amount of overhead and should only be used by those analyzing their system. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 16 ++++++++++++++++ kernel/trace/trace_branch.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 47 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 7e35487..61e8cca 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -173,6 +173,22 @@ config TRACE_BRANCH_PROFILING Say N if unsure. +config PROFILE_ALL_BRANCHES + bool "Profile all if conditionals" + depends on TRACE_BRANCH_PROFILING + help + This tracer profiles all branch conditions. Every if () + taken in the kernel is recorded whether it hit or miss. + The results will be displayed in: + + /debugfs/tracing/profile_branch + + This configuration, when enabled, will impose a great overhead + on the system. This should only be enabled when the system + is to be analyzed + + Say N if unsure. + config TRACING_BRANCHES bool help diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 142acb3..85792ae 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -185,6 +185,7 @@ EXPORT_SYMBOL(ftrace_likely_update); struct ftrace_pointer { void *start; void *stop; + int hit; }; static void * @@ -223,13 +224,17 @@ static void t_stop(struct seq_file *m, void *p) static int t_show(struct seq_file *m, void *v) { + struct ftrace_pointer *fp = m->private; struct ftrace_branch_data *p = v; const char *f; long percent; if (v == (void *)1) { - seq_printf(m, " correct incorrect %% " - " Function " + if (fp->hit) + seq_printf(m, " miss hit %% "); + else + seq_printf(m, " correct incorrect %% "); + seq_printf(m, " Function " " File Line\n" " ------- --------- - " " -------- " @@ -243,6 +248,9 @@ static int t_show(struct seq_file *m, void *v) f--; f++; + /* + * The miss is overlayed on correct, and hit on incorrect. + */ if (p->correct) { percent = p->incorrect * 100; percent /= p->correct + p->incorrect; @@ -284,6 +292,18 @@ static const struct file_operations tracing_branch_fops = { .llseek = seq_lseek, }; +#ifdef CONFIG_PROFILE_ALL_BRANCHES +extern unsigned long __start_branch_profile[]; +extern unsigned long __stop_branch_profile[]; + +static struct ftrace_pointer ftrace_branch_pos = { + .start = __start_branch_profile, + .stop = __stop_branch_profile, + .hit = 1, +}; + +#endif /* CONFIG_PROFILE_ALL_BRANCHES */ + extern unsigned long __start_annotated_branch_profile[]; extern unsigned long __stop_annotated_branch_profile[]; @@ -306,6 +326,15 @@ static __init int ftrace_branch_init(void) pr_warning("Could not create debugfs " "'profile_annotatet_branch' entry\n"); +#ifdef CONFIG_PROFILE_ALL_BRANCHES + entry = debugfs_create_file("profile_branch", 0444, d_tracer, + &ftrace_branch_pos, + &tracing_branch_fops); + if (!entry) + pr_warning("Could not create debugfs" + " 'profile_branch' entry\n"); +#endif + return 0; } -- cgit v1.1 From 033601a32b2012b6948e80e739cca40bff4de4a0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 12:41:55 -0500 Subject: ring-buffer: add tracing_off_permanent Impact: feature to permanently disable ring buffer This patch adds a API to the ring buffer code that will permanently disable the ring buffer from ever recording. This should only be called when some serious anomaly is detected, and the system may be in an unstable state. When that happens, shutting down the recording to the ring buffers may be appropriate. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer.c | 79 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 66 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 85ced14..e206951 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -18,8 +18,46 @@ #include "trace.h" -/* Global flag to disable all recording to ring buffers */ -static int ring_buffers_off __read_mostly; +/* + * A fast way to enable or disable all ring buffers is to + * call tracing_on or tracing_off. Turning off the ring buffers + * prevents all ring buffers from being recorded to. + * Turning this switch on, makes it OK to write to the + * ring buffer, if the ring buffer is enabled itself. + * + * There's three layers that must be on in order to write + * to the ring buffer. + * + * 1) This global flag must be set. + * 2) The ring buffer must be enabled for recording. + * 3) The per cpu buffer must be enabled for recording. + * + * In case of an anomaly, this global flag has a bit set that + * will permantly disable all ring buffers. + */ + +/* + * Global flag to disable all recording to ring buffers + * This has two bits: ON, DISABLED + * + * ON DISABLED + * ---- ---------- + * 0 0 : ring buffers are off + * 1 0 : ring buffers are on + * X 1 : ring buffers are permanently disabled + */ + +enum { + RB_BUFFERS_ON_BIT = 0, + RB_BUFFERS_DISABLED_BIT = 1, +}; + +enum { + RB_BUFFERS_ON = 1 << RB_BUFFERS_ON_BIT, + RB_BUFFERS_DISABLED = 1 << RB_BUFFERS_DISABLED_BIT, +}; + +static long ring_buffer_flags __read_mostly = RB_BUFFERS_ON; /** * tracing_on - enable all tracing buffers @@ -29,7 +67,7 @@ static int ring_buffers_off __read_mostly; */ void tracing_on(void) { - ring_buffers_off = 0; + set_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags); } /** @@ -42,7 +80,18 @@ void tracing_on(void) */ void tracing_off(void) { - ring_buffers_off = 1; + clear_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags); +} + +/** + * tracing_off_permanent - permanently disable ring buffers + * + * This function, once called, will disable all ring buffers + * permanenty. + */ +void tracing_off_permanent(void) +{ + set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags); } #include "trace.h" @@ -1185,7 +1234,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, struct ring_buffer_event *event; int cpu, resched; - if (ring_buffers_off) + if (ring_buffer_flags != RB_BUFFERS_ON) return NULL; if (atomic_read(&buffer->record_disabled)) @@ -1297,7 +1346,7 @@ int ring_buffer_write(struct ring_buffer *buffer, int ret = -EBUSY; int cpu, resched; - if (ring_buffers_off) + if (ring_buffer_flags != RB_BUFFERS_ON) return -EBUSY; if (atomic_read(&buffer->record_disabled)) @@ -2178,12 +2227,14 @@ static ssize_t rb_simple_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - int *p = filp->private_data; + long *p = filp->private_data; char buf[64]; int r; - /* !ring_buffers_off == tracing_on */ - r = sprintf(buf, "%d\n", !*p); + if (test_bit(RB_BUFFERS_DISABLED_BIT, p)) + r = sprintf(buf, "permanently disabled\n"); + else + r = sprintf(buf, "%d\n", test_bit(RB_BUFFERS_ON_BIT, p)); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } @@ -2192,7 +2243,7 @@ static ssize_t rb_simple_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - int *p = filp->private_data; + long *p = filp->private_data; char buf[64]; long val; int ret; @@ -2209,8 +2260,10 @@ rb_simple_write(struct file *filp, const char __user *ubuf, if (ret < 0) return ret; - /* !ring_buffers_off == tracing_on */ - *p = !val; + if (val) + set_bit(RB_BUFFERS_ON_BIT, p); + else + clear_bit(RB_BUFFERS_ON_BIT, p); (*ppos)++; @@ -2232,7 +2285,7 @@ static __init int rb_init_debugfs(void) d_tracer = tracing_init_dentry(); entry = debugfs_create_file("tracing_on", 0644, d_tracer, - &ring_buffers_off, &rb_simple_fops); + &ring_buffer_flags, &rb_simple_fops); if (!entry) pr_warning("Could not create debugfs 'tracing_on' entry\n"); -- cgit v1.1 From 69bb54ec05f57da7f6fac2cec0820cbc970df20f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 12:59:38 -0500 Subject: ftrace: add ftrace_off_permanent Impact: add new API to disable all of ftrace on anomalies It case of a serious anomaly being detected (like something caught by lockdep) it is a good idea to disable all tracing immediately, without grabing any locks. This patch adds ftrace_off_permanent that disables the tracers, function tracing and ring buffers without a way to enable them again. This should only be used when something serious has been detected. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4ee6f03..0dbfb23 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -661,6 +661,21 @@ static int trace_stop_count; static DEFINE_SPINLOCK(tracing_start_lock); /** + * ftrace_off_permanent - disable all ftrace code permanently + * + * This should only be called when a serious anomally has + * been detected. This will turn off the function tracing, + * ring buffers, and other tracing utilites. It takes no + * locks and can be called from any context. + */ +void ftrace_off_permanent(void) +{ + tracing_disabled = 1; + ftrace_stop(); + tracing_off_permanent(); +} + +/** * tracing_start - quick start of the tracer * * If tracing is enabled but was stopped by tracing_stop, -- cgit v1.1 From 0429149fb5e01edc410648591c19095d2074ee00 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 14:44:57 -0500 Subject: trace: fix compiler warning in branch profiler Impact: fix compiler warning The ftrace_pointers used in the branch profiler are constant values. They should never change. But the compiler complains when they are passed into the debugfs_create_file as a data pointer, because the function discards the qualifier. This patch typecasts the parameter to debugfs_create_file back to a void pointer. To remind the callbacks that they are pointing to a constant value, I also modified the callback local pointers to be const struct ftrace_pointer * as well. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_branch.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 85792ae..877ee88 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -191,7 +191,7 @@ struct ftrace_pointer { static void * t_next(struct seq_file *m, void *v, loff_t *pos) { - struct ftrace_pointer *f = m->private; + const struct ftrace_pointer *f = m->private; struct ftrace_branch_data *p = v; (*pos)++; @@ -224,7 +224,7 @@ static void t_stop(struct seq_file *m, void *p) static int t_show(struct seq_file *m, void *v) { - struct ftrace_pointer *fp = m->private; + const struct ftrace_pointer *fp = m->private; struct ftrace_branch_data *p = v; const char *f; long percent; @@ -296,7 +296,7 @@ static const struct file_operations tracing_branch_fops = { extern unsigned long __start_branch_profile[]; extern unsigned long __stop_branch_profile[]; -static struct ftrace_pointer ftrace_branch_pos = { +static const struct ftrace_pointer ftrace_branch_pos = { .start = __start_branch_profile, .stop = __stop_branch_profile, .hit = 1, @@ -320,7 +320,7 @@ static __init int ftrace_branch_init(void) d_tracer = tracing_init_dentry(); entry = debugfs_create_file("profile_annotated_branch", 0444, d_tracer, - &ftrace_annotated_branch_pos, + (void *)&ftrace_annotated_branch_pos, &tracing_branch_fops); if (!entry) pr_warning("Could not create debugfs " @@ -328,7 +328,7 @@ static __init int ftrace_branch_init(void) #ifdef CONFIG_PROFILE_ALL_BRANCHES entry = debugfs_create_file("profile_branch", 0444, d_tracer, - &ftrace_branch_pos, + (void *)&ftrace_branch_pos, &tracing_branch_fops); if (!entry) pr_warning("Could not create debugfs" -- cgit v1.1 From 8d7c6a96164651dbbab449ef0b5c20ae1f76a3a1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sun, 23 Nov 2008 12:39:06 +0200 Subject: tracing/stack-tracer: fix style issues MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: cleanup Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 62776b7..dedf35f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -948,9 +948,9 @@ static void ftrace_trace_userstack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, int pc) { + struct ring_buffer_event *event; struct userstack_entry *entry; struct stack_trace trace; - struct ring_buffer_event *event; unsigned long irq_flags; if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) @@ -1471,8 +1471,7 @@ static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, if (file) { ret = trace_seq_path(s, &file->f_path); if (ret) - ret = trace_seq_printf(s, "[+0x%lx]", - ip - vmstart); + ret = trace_seq_printf(s, "[+0x%lx]", ip - vmstart); } if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file)) ret = trace_seq_printf(s, " <" IP_FMT ">", ip); @@ -1485,7 +1484,7 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, { struct mm_struct *mm = NULL; int ret = 1; - unsigned i; + unsigned int i; if (trace_flags & TRACE_ITER_SYM_USEROBJ) { struct task_struct *task; -- cgit v1.1 From cffa10aecb6891f090a4d53a075bc40c082c45fc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sun, 23 Nov 2008 12:39:07 +0200 Subject: tracing/stack-tracer: fix locking and refcounts MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: fix refcounting/object-access bug Hold mmap_sem while looking up/accessing vma. Hold the RCU lock while using the task we looked up. Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dedf35f..4c3bd82 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1462,11 +1462,15 @@ static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, int ret = 1; if (mm) { - const struct vm_area_struct *vma = find_vma(mm, ip); + const struct vm_area_struct *vma; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, ip); if (vma) { file = vma->vm_file; vmstart = vma->vm_start; } + up_read(&mm->mmap_sem); } if (file) { ret = trace_seq_path(s, &file->f_path); @@ -1494,10 +1498,9 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, */ rcu_read_lock(); task = find_task_by_vpid(entry->ent.tgid); - rcu_read_unlock(); - if (task) mm = get_task_mm(task); + rcu_read_unlock(); } for (i = 0; i < FTRACE_STACK_ENTRIES; i++) { -- cgit v1.1 From 8d26487fd4ddda7a0237da418fb8669fb06ae557 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sun, 23 Nov 2008 12:39:08 +0200 Subject: tracing/stack-tracer: introduce CONFIG_USER_STACKTRACE_SUPPORT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: cleanup User stack tracing is just implemented for x86, but it is not x86 specific. Introduce a generic config flag, that is currently enabled only for x86. When other arches implement it, they will have to SELECT USER_STACKTRACE_SUPPORT. Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/trace/Kconfig | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index b8378fa..87fc34a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -3,6 +3,9 @@ # select HAVE_FUNCTION_TRACER: # +config USER_STACKTRACE_SUPPORT + bool + config NOP_TRACER bool -- cgit v1.1 From e38da59269be8c0196d16dff1be5bb26076afc6a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Sun, 23 Nov 2008 13:08:10 +0200 Subject: tracing/stack-tracer: avoid races accessing file Impact: fix race vma->vm_file reference is only stable while holding the mmap_sem, so move usage of it to within the critical section. Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4c3bd82..48d1536 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1470,13 +1470,13 @@ static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, file = vma->vm_file; vmstart = vma->vm_start; } + if (file) { + ret = trace_seq_path(s, &file->f_path); + if (ret) + ret = trace_seq_printf(s, "[+0x%lx]", ip - vmstart); + } up_read(&mm->mmap_sem); } - if (file) { - ret = trace_seq_path(s, &file->f_path); - if (ret) - ret = trace_seq_printf(s, "[+0x%lx]", ip - vmstart); - } if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file)) ret = trace_seq_printf(s, " <" IP_FMT ">", ip); return ret; -- cgit v1.1 From eae849ca034c7f1015f0a6f17421ebc737f0a069 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 23 Nov 2008 17:33:12 +0100 Subject: tracing/function-return-tracer: don't trace kfree while it frees the return stack Impact: fix a crash While I killed the cat process, I got sometimes the following (but rare) crash: [ 65.689027] Pid: 2969, comm: cat Not tainted (2.6.28-rc6-tip #83) AMILO Li 2727 [ 65.689027] EIP: 0060:[<00000000>] EFLAGS: 00010082 CPU: 1 [ 65.689027] EIP is at 0x0 [ 65.689027] EAX: 00000000 EBX: f66cd780 ECX: c019a64a EDX: f66cd780 [ 65.689027] ESI: 00000286 EDI: f66cd780 EBP: f630be2c ESP: f630be24 [ 65.689027] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 65.689027] Process cat (pid: 2969, ti=f630a000 task=f66cd780 task.ti=f630a000) [ 65.689027] Stack: [ 65.689027] 00000012 f630bd54 f630be7c c012c853 00000000 c0133cc9 f66cda54 f630be5c [ 65.689027] f630be68 f66cda54 f66cd88c f66cd878 f7070000 00000001 f630be90 c0135dbc [ 65.689027] f614a614 f630be68 f630be68 f65ba200 00000002 f630bf10 f630be90 c012cad6 [ 65.689027] Call Trace: [ 65.689027] [] ? do_exit+0x603/0x850 [ 65.689027] [] ? next_signal+0x9/0x40 [ 65.689027] [] ? dequeue_signal+0x8c/0x180 [ 65.689027] [] ? do_group_exit+0x36/0x90 [ 65.689027] [] ? get_signal_to_deliver+0x20c/0x390 [ 65.689027] [] ? do_notify_resume+0x99/0x8b0 [ 65.689027] [] ? tty_ldisc_deref+0x5a/0x80 [ 65.689027] [] ? trace_hardirqs_on+0xb/0x10 [ 65.689027] [] ? tty_ldisc_deref+0x5a/0x80 [ 65.689027] [] ? n_tty_write+0x0/0x340 [ 65.689027] [] ? redirected_tty_write+0x82/0x90 [ 65.689027] [] ? vfs_write+0x99/0xd0 [ 65.689027] [] ? redirected_tty_write+0x0/0x90 [ 65.689027] [] ? sys_write+0x42/0x70 [ 65.689027] [] ? work_notifysig+0x13/0x19 [ 65.689027] Code: Bad EIP value. [ 65.689027] EIP: [<00000000>] 0x0 SS:ESP 0068:f630be24 This is because on do_exit(), kfree is called to free the return addresses stack but kfree is traced and stored its return address in this stack. This patch fixes it. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 90d99fb..53042f1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1628,8 +1628,13 @@ void ftrace_retfunc_init_task(struct task_struct *t) void ftrace_retfunc_exit_task(struct task_struct *t) { - kfree(t->ret_stack); + struct ftrace_ret_stack *ret_stack = t->ret_stack; + t->ret_stack = NULL; + /* NULL must become visible to IRQs before we free it: */ + barrier(); + + kfree(ret_stack); } #endif -- cgit v1.1 From 7ee1768ddb3075ae3a0801cc2d0ea4195530a7db Mon Sep 17 00:00:00 2001 From: Pekka Paalanen Date: Sun, 23 Nov 2008 21:24:30 +0200 Subject: x86, mmiotrace: fix buffer overrun detection Impact: fix mmiotrace overrun tracing When ftrace framework moved to use the ring buffer facility, the buffer overrun detection was broken after 2.6.27 by commit | commit 3928a8a2d98081d1bc3c0a84a2d70e29b90ecf1c | Author: Steven Rostedt | Date: Mon Sep 29 23:02:41 2008 -0400 | | ftrace: make work with new ring buffer | | This patch ports ftrace over to the new ring buffer. The detection is now fixed by using the ring buffer API. When mmiotrace detects a buffer overrun, it will report the number of lost events. People reading an mmiotrace log must know if something was missed, otherwise the data may not make sense. Signed-off-by: Pekka Paalanen Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_mmiotrace.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index f284846..e62cbf7 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -18,12 +18,14 @@ struct header_iter { static struct trace_array *mmio_trace_array; static bool overrun_detected; +static unsigned long prev_overruns; static void mmio_reset_data(struct trace_array *tr) { int cpu; overrun_detected = false; + prev_overruns = 0; tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) @@ -128,16 +130,12 @@ static void mmio_close(struct trace_iterator *iter) static unsigned long count_overruns(struct trace_iterator *iter) { - int cpu; unsigned long cnt = 0; -/* FIXME: */ -#if 0 - for_each_online_cpu(cpu) { - cnt += iter->overrun[cpu]; - iter->overrun[cpu] = 0; - } -#endif - (void)cpu; + unsigned long over = ring_buffer_overruns(iter->tr->buffer); + + if (over > prev_overruns) + cnt = over - prev_overruns; + prev_overruns = over; return cnt; } -- cgit v1.1 From 65afa5e603d507014580ead016ec887b49e1afa6 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 23 Nov 2008 18:43:39 +0100 Subject: tracing/function-return-tracer: free the return stack on free_task() Impact: avoid losing some traces when a task is freed do_exit() is not the last function called when a task finishes. There are still some functions which are to be called such as ree_task(). So we delay the freeing of the return stack to the last moment. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/exit.c | 2 -- kernel/fork.c | 1 + 2 files changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index ef04d03..e5ae36e 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -47,7 +47,6 @@ #include #include #include -#include #include #include @@ -1128,7 +1127,6 @@ NORET_TYPE void do_exit(long code) preempt_disable(); /* causes final put_task_struct in finish_task_switch(). */ tsk->state = TASK_DEAD; - ftrace_retfunc_exit_task(tsk); schedule(); BUG(); /* Avoid "noreturn function does return". */ diff --git a/kernel/fork.c b/kernel/fork.c index fbf4a4c..d6e1a32 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -140,6 +140,7 @@ void free_task(struct task_struct *tsk) prop_local_destroy_single(&tsk->dirties); free_thread_info(tsk->stack); rt_mutex_debug_task_free(tsk); + ftrace_retfunc_exit_task(tsk); free_task_struct(tsk); } EXPORT_SYMBOL(free_task); -- cgit v1.1 From 7918baa555140989eeee1270f48533987d48fdba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edwin?= Date: Mon, 24 Nov 2008 10:17:42 +0200 Subject: mutex: __used is needed for function referenced only from inline asm MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Impact: fix build failure on llvm-gcc-4.2 According to the gcc manual, the 'used' attribute should be applied to functions referenced only from inline assembly. This fixes a build failure with llvm-gcc-4.2, which deleted __mutex_lock_slowpath, __mutex_unlock_slowpath. Signed-off-by: Török Edwin Signed-off-by: Ingo Molnar --- kernel/mutex.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/mutex.c b/kernel/mutex.c index 39a3816..4f45d4b 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -59,7 +59,7 @@ EXPORT_SYMBOL(__mutex_init); * We also put the fastpath first in the kernel image, to make sure the * branch is predicted by the CPU as default-untaken. */ -static void noinline __sched +static __used noinline void __sched __mutex_lock_slowpath(atomic_t *lock_count); /*** @@ -96,7 +96,7 @@ void inline __sched mutex_lock(struct mutex *lock) EXPORT_SYMBOL(mutex_lock); #endif -static noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count); +static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count); /*** * mutex_unlock - release the mutex @@ -268,7 +268,7 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested) /* * Release the lock, slowpath: */ -static noinline void +static __used noinline void __mutex_unlock_slowpath(atomic_t *lock_count) { __mutex_unlock_common_slowpath(lock_count, 1); @@ -313,7 +313,7 @@ int __sched mutex_lock_killable(struct mutex *lock) } EXPORT_SYMBOL(mutex_lock_killable); -static noinline void __sched +static __used noinline void __sched __mutex_lock_slowpath(atomic_t *lock_count) { struct mutex *lock = container_of(lock_count, struct mutex, count); -- cgit v1.1