diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/futex.c | 22 | ||||
| -rw-r--r-- | kernel/params.c | 65 | ||||
| -rw-r--r-- | kernel/perf_event.c | 46 | ||||
| -rw-r--r-- | kernel/printk.c | 100 | ||||
| -rw-r--r-- | kernel/rtmutex-debug.c | 1 | ||||
| -rw-r--r-- | kernel/rtmutex.c | 318 | ||||
| -rw-r--r-- | kernel/rtmutex_common.h | 16 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 78 | ||||
| -rw-r--r-- | kernel/sysctl.c | 3 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 7 |
10 files changed, 321 insertions, 335 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index b766d28..64c3811 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1556,10 +1556,10 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, /* * We are here either because we stole the rtmutex from the - * pending owner or we are the pending owner which failed to - * get the rtmutex. We have to replace the pending owner TID - * in the user space variable. This must be atomic as we have - * to preserve the owner died bit here. + * previous highest priority waiter or we are the highest priority + * waiter but failed to get the rtmutex the first time. + * We have to replace the newowner TID in the user space variable. + * This must be atomic as we have to preserve the owner died bit here. * * Note: We write the user space value _before_ changing the pi_state * because we can fault here. Imagine swapped out pages or a fork @@ -1608,8 +1608,8 @@ retry: /* * To handle the page fault we need to drop the hash bucket - * lock here. That gives the other task (either the pending - * owner itself or the task which stole the rtmutex) the + * lock here. That gives the other task (either the highest priority + * waiter itself or the task which stole the rtmutex) the * chance to try the fixup of the pi_state. So once we are * back from handling the fault we need to check the pi_state * after reacquiring the hash bucket lock and before trying to @@ -1685,18 +1685,20 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked) /* * pi_state is incorrect, some other task did a lock steal and * we returned due to timeout or signal without taking the - * rt_mutex. Too late. We can access the rt_mutex_owner without - * locking, as the other task is now blocked on the hash bucket - * lock. Fix the state up. + * rt_mutex. Too late. */ + raw_spin_lock(&q->pi_state->pi_mutex.wait_lock); owner = rt_mutex_owner(&q->pi_state->pi_mutex); + if (!owner) + owner = rt_mutex_next_owner(&q->pi_state->pi_mutex); + raw_spin_unlock(&q->pi_state->pi_mutex.wait_lock); ret = fixup_pi_state_owner(uaddr, q, owner); goto out; } /* * Paranoia check. If we did not take the lock, then we should not be - * the owner, nor the pending owner, of the rt_mutex. + * the owner of the rt_mutex. */ if (rt_mutex_owner(&q->pi_state->pi_mutex) == current) printk(KERN_ERR "fixup_owner: ret = %d pi-mutex: %p " diff --git a/kernel/params.c b/kernel/params.c index 08107d1..0da1411 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -719,9 +719,7 @@ void destroy_params(const struct kernel_param *params, unsigned num) params[i].ops->free(params[i].arg); } -static void __init kernel_add_sysfs_param(const char *name, - struct kernel_param *kparam, - unsigned int name_skip) +static struct module_kobject * __init locate_module_kobject(const char *name) { struct module_kobject *mk; struct kobject *kobj; @@ -729,10 +727,7 @@ static void __init kernel_add_sysfs_param(const char *name, kobj = kset_find_obj(module_kset, name); if (kobj) { - /* We already have one. Remove params so we can add more. */ mk = to_module_kobject(kobj); - /* We need to remove it before adding parameters. */ - sysfs_remove_group(&mk->kobj, &mk->mp->grp); } else { mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL); BUG_ON(!mk); @@ -743,15 +738,36 @@ static void __init kernel_add_sysfs_param(const char *name, "%s", name); if (err) { kobject_put(&mk->kobj); - printk(KERN_ERR "Module '%s' failed add to sysfs, " - "error number %d\n", name, err); - printk(KERN_ERR "The system will be unstable now.\n"); - return; + printk(KERN_ERR + "Module '%s' failed add to sysfs, error number %d\n", + name, err); + printk(KERN_ERR + "The system will be unstable now.\n"); + return NULL; } - /* So that exit path is even. */ + + /* So that we hold reference in both cases. */ kobject_get(&mk->kobj); } + return mk; +} + +static void __init kernel_add_sysfs_param(const char *name, + struct kernel_param *kparam, + unsigned int name_skip) +{ + struct module_kobject *mk; + int err; + + mk = locate_module_kobject(name); + if (!mk) + return; + + /* We need to remove old parameters before adding more. */ + if (mk->mp) + sysfs_remove_group(&mk->kobj, &mk->mp->grp); + /* These should not fail at boot. */ err = add_sysfs_param(mk, kparam, kparam->name + name_skip); BUG_ON(err); @@ -796,6 +812,32 @@ static void __init param_sysfs_builtin(void) } } +ssize_t __modver_version_show(struct module_attribute *mattr, + struct module *mod, char *buf) +{ + struct module_version_attribute *vattr = + container_of(mattr, struct module_version_attribute, mattr); + + return sprintf(buf, "%s\n", vattr->version); +} + +extern struct module_version_attribute __start___modver[], __stop___modver[]; + +static void __init version_sysfs_builtin(void) +{ + const struct module_version_attribute *vattr; + struct module_kobject *mk; + int err; + + for (vattr = __start___modver; vattr < __stop___modver; vattr++) { + mk = locate_module_kobject(vattr->module_name); + if (mk) { + err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); + kobject_uevent(&mk->kobj, KOBJ_ADD); + kobject_put(&mk->kobj); + } + } +} /* module-related sysfs stuff */ @@ -875,6 +917,7 @@ static int __init param_sysfs_init(void) } module_sysfs_initialized = 1; + version_sysfs_builtin(); param_sysfs_builtin(); return 0; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 84522c7..126a302 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2201,13 +2201,6 @@ find_lively_task_by_vpid(pid_t vpid) if (!task) return ERR_PTR(-ESRCH); - /* - * Can't attach events to a dying task. - */ - err = -ESRCH; - if (task->flags & PF_EXITING) - goto errout; - /* Reuse ptrace permission checks for now. */ err = -EACCES; if (!ptrace_may_access(task, PTRACE_MODE_READ)) @@ -2268,14 +2261,27 @@ retry: get_ctx(ctx); - if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) { - /* - * We raced with some other task; use - * the context they set. - */ + err = 0; + mutex_lock(&task->perf_event_mutex); + /* + * If it has already passed perf_event_exit_task(). + * we must see PF_EXITING, it takes this mutex too. + */ + if (task->flags & PF_EXITING) + err = -ESRCH; + else if (task->perf_event_ctxp[ctxn]) + err = -EAGAIN; + else + rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); + mutex_unlock(&task->perf_event_mutex); + + if (unlikely(err)) { put_task_struct(task); kfree(ctx); - goto retry; + + if (err == -EAGAIN) + goto retry; + goto errout; } } @@ -5374,6 +5380,8 @@ free_dev: goto out; } +static struct lock_class_key cpuctx_mutex; + int perf_pmu_register(struct pmu *pmu, char *name, int type) { int cpu, ret; @@ -5422,6 +5430,7 @@ skip_type: cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); __perf_event_init_context(&cpuctx->ctx); + lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); cpuctx->ctx.type = cpu_context; cpuctx->ctx.pmu = pmu; cpuctx->jiffies_interval = 1; @@ -6127,7 +6136,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn) * scheduled, so we are now safe from rescheduling changing * our context. */ - child_ctx = child->perf_event_ctxp[ctxn]; + child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]); task_ctx_sched_out(child_ctx, EVENT_ALL); /* @@ -6440,11 +6449,6 @@ int perf_event_init_context(struct task_struct *child, int ctxn) unsigned long flags; int ret = 0; - child->perf_event_ctxp[ctxn] = NULL; - - mutex_init(&child->perf_event_mutex); - INIT_LIST_HEAD(&child->perf_event_list); - if (likely(!parent->perf_event_ctxp[ctxn])) return 0; @@ -6533,6 +6537,10 @@ int perf_event_init_task(struct task_struct *child) { int ctxn, ret; + memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); + mutex_init(&child->perf_event_mutex); + INIT_LIST_HEAD(&child->perf_event_list); + for_each_task_context_nr(ctxn) { ret = perf_event_init_context(child, ctxn); if (ret) diff --git a/kernel/printk.c b/kernel/printk.c index 53d9a9e..2ddbdc7 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -97,7 +97,7 @@ static int console_locked, console_suspended; /* * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars * It is also used in interesting ways to provide interlocking in - * release_console_sem(). + * console_unlock();. */ static DEFINE_SPINLOCK(logbuf_lock); @@ -501,7 +501,7 @@ static void _call_console_drivers(unsigned start, /* * Call the console drivers, asking them to write out * log_buf[start] to log_buf[end - 1]. - * The console_sem must be held. + * The console_lock must be held. */ static void call_console_drivers(unsigned start, unsigned end) { @@ -604,11 +604,11 @@ static int have_callable_console(void) * * This is printk(). It can be called from any context. We want it to work. * - * We try to grab the console_sem. If we succeed, it's easy - we log the output and + * We try to grab the console_lock. If we succeed, it's easy - we log the output and * call the console drivers. If we fail to get the semaphore we place the output * into the log buffer and return. The current holder of the console_sem will - * notice the new output in release_console_sem() and will send it to the - * consoles before releasing the semaphore. + * notice the new output in console_unlock(); and will send it to the + * consoles before releasing the lock. * * One effect of this deferred printing is that code which calls printk() and * then changes console_loglevel may break. This is because console_loglevel @@ -659,19 +659,19 @@ static inline int can_use_console(unsigned int cpu) /* * Try to get console ownership to actually show the kernel * messages from a 'printk'. Return true (and with the - * console_semaphore held, and 'console_locked' set) if it + * console_lock held, and 'console_locked' set) if it * is successful, false otherwise. * * This gets called with the 'logbuf_lock' spinlock held and * interrupts disabled. It should return with 'lockbuf_lock' * released but interrupts still disabled. */ -static int acquire_console_semaphore_for_printk(unsigned int cpu) +static int console_trylock_for_printk(unsigned int cpu) __releases(&logbuf_lock) { int retval = 0; - if (!try_acquire_console_sem()) { + if (console_trylock()) { retval = 1; /* @@ -827,12 +827,12 @@ asmlinkage int vprintk(const char *fmt, va_list args) * actual magic (print out buffers, wake up klogd, * etc). * - * The acquire_console_semaphore_for_printk() function + * The console_trylock_for_printk() function * will release 'logbuf_lock' regardless of whether it * actually gets the semaphore or not. */ - if (acquire_console_semaphore_for_printk(this_cpu)) - release_console_sem(); + if (console_trylock_for_printk(this_cpu)) + console_unlock(); lockdep_on(); out_restore_irqs: @@ -993,7 +993,7 @@ void suspend_console(void) if (!console_suspend_enabled) return; printk("Suspending console(s) (use no_console_suspend to debug)\n"); - acquire_console_sem(); + console_lock(); console_suspended = 1; up(&console_sem); } @@ -1004,7 +1004,7 @@ void resume_console(void) return; down(&console_sem); console_suspended = 0; - release_console_sem(); + console_unlock(); } /** @@ -1027,21 +1027,21 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self, case CPU_DYING: case CPU_DOWN_FAILED: case CPU_UP_CANCELED: - acquire_console_sem(); - release_console_sem(); + console_lock(); + console_unlock(); } return NOTIFY_OK; } /** - * acquire_console_sem - lock the console system for exclusive use. + * console_lock - lock the console system for exclusive use. * - * Acquires a semaphore which guarantees that the caller has + * Acquires a lock which guarantees that the caller has * exclusive access to the console system and the console_drivers list. * * Can sleep, returns nothing. */ -void acquire_console_sem(void) +void console_lock(void) { BUG_ON(in_interrupt()); down(&console_sem); @@ -1050,21 +1050,29 @@ void acquire_console_sem(void) console_locked = 1; console_may_schedule = 1; } -EXPORT_SYMBOL(acquire_console_sem); +EXPORT_SYMBOL(console_lock); -int try_acquire_console_sem(void) +/** + * console_trylock - try to lock the console system for exclusive use. + * + * Tried to acquire a lock which guarantees that the caller has + * exclusive access to the console system and the console_drivers list. + * + * returns 1 on success, and 0 on failure to acquire the lock. + */ +int console_trylock(void) { if (down_trylock(&console_sem)) - return -1; + return 0; if (console_suspended) { up(&console_sem); - return -1; + return 0; } console_locked = 1; console_may_schedule = 0; - return 0; + return 1; } -EXPORT_SYMBOL(try_acquire_console_sem); +EXPORT_SYMBOL(console_trylock); int is_console_locked(void) { @@ -1095,20 +1103,20 @@ void wake_up_klogd(void) } /** - * release_console_sem - unlock the console system + * console_unlock - unlock the console system * - * Releases the semaphore which the caller holds on the console system + * Releases the console_lock which the caller holds on the console system * and the console driver list. * - * While the semaphore was held, console output may have been buffered - * by printk(). If this is the case, release_console_sem() emits - * the output prior to releasing the semaphore. + * While the console_lock was held, console output may have been buffered + * by printk(). If this is the case, console_unlock(); emits + * the output prior to releasing the lock. * * If there is output waiting for klogd, we wake it up. * - * release_console_sem() may be called from any context. + * console_unlock(); may be called from any context. */ -void release_console_sem(void) +void console_unlock(void) { unsigned long flags; unsigned _con_start, _log_end; @@ -1141,7 +1149,7 @@ void release_console_sem(void) if (wake_klogd) wake_up_klogd(); } -EXPORT_SYMBOL(release_console_sem); +EXPORT_SYMBOL(console_unlock); /** * console_conditional_schedule - yield the CPU if required @@ -1150,7 +1158,7 @@ EXPORT_SYMBOL(release_console_sem); * if this CPU should yield the CPU to another task, do * so here. * - * Must be called within acquire_console_sem(). + * Must be called within console_lock();. */ void __sched console_conditional_schedule(void) { @@ -1171,14 +1179,14 @@ void console_unblank(void) if (down_trylock(&console_sem) != 0) return; } else - acquire_console_sem(); + console_lock(); console_locked = 1; console_may_schedule = 0; for_each_console(c) if ((c->flags & CON_ENABLED) && c->unblank) c->unblank(); - release_console_sem(); + console_unlock(); } /* @@ -1189,7 +1197,7 @@ struct tty_driver *console_device(int *index) struct console *c; struct tty_driver *driver = NULL; - acquire_console_sem(); + console_lock(); for_each_console(c) { if (!c->device) continue; @@ -1197,7 +1205,7 @@ struct tty_driver *console_device(int *index) if (driver) break; } - release_console_sem(); + console_unlock(); return driver; } @@ -1208,17 +1216,17 @@ struct tty_driver *console_device(int *index) */ void console_stop(struct console *console) { - acquire_console_sem(); + console_lock(); console->flags &= ~CON_ENABLED; - release_console_sem(); + console_unlock(); } EXPORT_SYMBOL(console_stop); void console_start(struct console *console) { - acquire_console_sem(); + console_lock(); console->flags |= CON_ENABLED; - release_console_sem(); + console_unlock(); } EXPORT_SYMBOL(console_start); @@ -1340,7 +1348,7 @@ void register_console(struct console *newcon) * Put this console in the list - keep the * preferred driver at the head of the list. */ - acquire_console_sem(); + console_lock(); if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { newcon->next = console_drivers; console_drivers = newcon; @@ -1352,14 +1360,14 @@ void register_console(struct console *newcon) } if (newcon->flags & CON_PRINTBUFFER) { /* - * release_console_sem() will print out the buffered messages + * console_unlock(); will print out the buffered messages * for us. */ spin_lock_irqsave(&logbuf_lock, flags); con_start = log_start; spin_unlock_irqrestore(&logbuf_lock, flags); } - release_console_sem(); + console_unlock(); console_sysfs_notify(); /* @@ -1396,7 +1404,7 @@ int unregister_console(struct console *console) return braille_unregister_console(console); #endif - acquire_console_sem(); + console_lock(); if (console_drivers == console) { console_drivers=console->next; res = 0; @@ -1418,7 +1426,7 @@ int unregister_console(struct console *console) if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; - release_console_sem(); + console_unlock(); console_sysfs_notify(); return res; } diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c index ddabb54..3c7cbc2 100644 --- a/kernel/rtmutex-debug.c +++ b/kernel/rtmutex-debug.c @@ -215,7 +215,6 @@ void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) put_pid(waiter->deadlock_task_pid); TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry)); TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry)); - TRACE_WARN_ON(waiter->task); memset(waiter, 0x22, sizeof(*waiter)); } diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index a960481..ab44911 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -20,41 +20,34 @@ /* * lock->owner state tracking: * - * lock->owner holds the task_struct pointer of the owner. Bit 0 and 1 - * are used to keep track of the "owner is pending" and "lock has - * waiters" state. + * lock->owner holds the task_struct pointer of the owner. Bit 0 + * is used to keep track of the "lock has waiters" state. * - * owner bit1 bit0 - * NULL 0 0 lock is free (fast acquire possible) - * NULL 0 1 invalid state - * NULL 1 0 Transitional State* - * NULL 1 1 invalid state - * taskpointer 0 0 lock is held (fast release possible) - * taskpointer 0 1 task is pending owner - * taskpointer 1 0 lock is held and has waiters - * taskpointer 1 1 task is pending owner and lock has more waiters - * - * Pending ownership is assigned to the top (highest priority) - * waiter of the lock, when the lock is released. The thread is woken - * up and can now take the lock. Until the lock is taken (bit 0 - * cleared) a competing higher priority thread can steal the lock - * which puts the woken up thread back on the waiters list. + * owner bit0 + * NULL 0 lock is free (fast acquire possible) + * NULL 1 lock is free and has waiters and the top waiter + * is going to take the lock* + * taskpointer 0 lock is held (fast release possible) + * taskpointer 1 lock is held and has waiters** * * The fast atomic compare exchange based acquire and release is only - * possible when bit 0 and 1 of lock->owner are 0. + * possible when bit 0 of lock->owner is 0. + * + * (*) It also can be a transitional state when grabbing the lock + * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock, + * we need to set the bit0 before looking at the lock, and the owner may be + * NULL in this small time, hence this can be a transitional state. * - * (*) There's a small time where the owner can be NULL and the - * "lock has waiters" bit is set. This can happen when grabbing the lock. - * To prevent a cmpxchg of the owner releasing the lock, we need to set this - * bit before looking at the lock, hence the reason this is a transitional - * state. + * (**) There is a small time when bit 0 is set but there are no + * waiters. This can happen when grabbing the lock in the slow path. + * To prevent a cmpxchg of the owner releasing the lock, we need to + * set this bit before looking at the lock. */ static void -rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner, - unsigned long mask) +rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner) { - unsigned long val = (unsigned long)owner | mask; + unsigned long val = (unsigned long)owner; if (rt_mutex_has_waiters(lock)) val |= RT_MUTEX_HAS_WAITERS; @@ -203,15 +196,14 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, * reached or the state of the chain has changed while we * dropped the locks. */ - if (!waiter || !waiter->task) + if (!waiter) goto out_unlock_pi; /* * Check the orig_waiter state. After we dropped the locks, - * the previous owner of the lock might have released the lock - * and made us the pending owner: + * the previous owner of the lock might have released the lock. */ - if (orig_waiter && !orig_waiter->task) + if (orig_waiter && !rt_mutex_owner(orig_lock)) goto out_unlock_pi; /* @@ -254,6 +246,17 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, /* Release the task */ raw_spin_unlock_irqrestore(&task->pi_lock, flags); + if (!rt_mutex_owner(lock)) { + /* + * If the requeue above changed the top waiter, then we need + * to wake the new top waiter up to try to get the lock. + */ + + if (top_waiter != rt_mutex_top_waiter(lock)) + wake_up_process(rt_mutex_top_waiter(lock)->task); + raw_spin_unlock(&lock->wait_lock); + goto out_put_task; + } put_task_struct(task); /* Grab the next task */ @@ -296,78 +299,16 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, } /* - * Optimization: check if we can steal the lock from the - * assigned pending owner [which might not have taken the - * lock yet]: - */ -static inline int try_to_steal_lock(struct rt_mutex *lock, - struct task_struct *task) -{ - struct task_struct *pendowner = rt_mutex_owner(lock); - struct rt_mutex_waiter *next; - unsigned long flags; - - if (!rt_mutex_owner_pending(lock)) - return 0; - - if (pendowner == task) - return 1; - - raw_spin_lock_irqsave(&pendowner->pi_lock, flags); - if (task->prio >= pendowner->prio) { - raw_spin_unlock_irqrestore(&pendowner->pi_lock, flags); - return 0; - } - - /* - * Check if a waiter is enqueued on the pending owners - * pi_waiters list. Remove it and readjust pending owners - * priority. - */ - if (likely(!rt_mutex_has_waiters(lock))) { - raw_spin_unlock_irqrestore(&pendowner->pi_lock, flags); - return 1; - } - - /* No chain handling, pending owner is not blocked on anything: */ - next = rt_mutex_top_waiter(lock); - plist_del(&next->pi_list_entry, &pendowner->pi_waiters); - __rt_mutex_adjust_prio(pendowner); - raw_spin_unlock_irqrestore(&pendowner->pi_lock, flags); - - /* - * We are going to steal the lock and a waiter was - * enqueued on the pending owners pi_waiters queue. So - * we have to enqueue this waiter into - * task->pi_waiters list. This covers the case, - * where task is boosted because it holds another - * lock and gets unboosted because the booster is - * interrupted, so we would delay a waiter with higher - * priority as task->normal_prio. - * - * Note: in the rare case of a SCHED_OTHER task changing - * its priority and thus stealing the lock, next->task - * might be task: - */ - if (likely(next->task != task)) { - raw_spin_lock_irqsave(&task->pi_lock, flags); - plist_add(&next->pi_list_entry, &task->pi_waiters); - __rt_mutex_adjust_prio(task); - raw_spin_unlock_irqrestore(&task->pi_lock, flags); - } - return 1; -} - -/* * Try to take an rt-mutex * - * This fails - * - when the lock has a real owner - * - when a different pending owner exists and has higher priority than current - * * Must be called with lock->wait_lock held. + * + * @lock: the lock to be acquired. + * @task: the task which wants to acquire the lock + * @waiter: the waiter that is queued to the lock's wait list. (could be NULL) */ -static int try_to_take_rt_mutex(struct rt_mutex *lock) +static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, + struct rt_mutex_waiter *waiter) { /* * We have to be careful here if the atomic speedups are @@ -390,15 +331,52 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock) */ mark_rt_mutex_waiters(lock); - if (rt_mutex_owner(lock) && !try_to_steal_lock(lock, current)) + if (rt_mutex_owner(lock)) return 0; + /* + * It will get the lock because of one of these conditions: + * 1) there is no waiter + * 2) higher priority than waiters + * 3) it is top waiter + */ + if (rt_mutex_has_waiters(lock)) { + if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) { + if (!waiter || waiter != rt_mutex_top_waiter(lock)) + return 0; + } + } + + if (waiter || rt_mutex_has_waiters(lock)) { + unsigned long flags; + struct rt_mutex_waiter *top; + + raw_spin_lock_irqsave(&task->pi_lock, flags); + + /* remove the queued waiter. */ + if (waiter) { + plist_del(&waiter->list_entry, &lock->wait_list); + task->pi_blocked_on = NULL; + } + + /* + * We have to enqueue the top waiter(if it exists) into + * task->pi_waiters list. + */ + if (rt_mutex_has_waiters(lock)) { + top = rt_mutex_top_waiter(lock); + top->pi_list_entry.prio = top->list_entry.prio; + plist_add(&top->pi_list_entry, &task->pi_waiters); + } + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + } + /* We got the lock. */ debug_rt_mutex_lock(lock); - rt_mutex_set_owner(lock, current, 0); + rt_mutex_set_owner(lock, task); - rt_mutex_deadlock_account_lock(lock, current); + rt_mutex_deadlock_account_lock(lock, task); return 1; } @@ -436,6 +414,9 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, raw_spin_unlock_irqrestore(&task->pi_lock, flags); + if (!owner) + return 0; + if (waiter == rt_mutex_top_waiter(lock)) { raw_spin_lock_irqsave(&owner->pi_lock, flags); plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters); @@ -472,21 +453,18 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, /* * Wake up the next waiter on the lock. * - * Remove the top waiter from the current tasks waiter list and from - * the lock waiter list. Set it as pending owner. Then wake it up. + * Remove the top waiter from the current tasks waiter list and wake it up. * * Called with lock->wait_lock held. */ static void wakeup_next_waiter(struct rt_mutex *lock) { struct rt_mutex_waiter *waiter; - struct task_struct *pendowner; unsigned long flags; raw_spin_lock_irqsave(¤t->pi_lock, flags); waiter = rt_mutex_top_waiter(lock); - plist_del(&waiter->list_entry, &lock->wait_list); /* * Remove it from current->pi_waiters. We do not adjust a @@ -495,43 +473,19 @@ static void wakeup_next_waiter(struct rt_mutex *lock) * lock->wait_lock. */ plist_del(&waiter->pi_list_entry, ¤t->pi_waiters); - pendowner = waiter->task; - waiter->task = NULL; - rt_mutex_set_owner(lock, pendowner, RT_MUTEX_OWNER_PENDING); + rt_mutex_set_owner(lock, NULL); raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - /* - * Clear the pi_blocked_on variable and enqueue a possible - * waiter into the pi_waiters list of the pending owner. This - * prevents that in case the pending owner gets unboosted a - * waiter with higher priority than pending-owner->normal_prio - * is blocked on the unboosted (pending) owner. - */ - raw_spin_lock_irqsave(&pendowner->pi_lock, flags); - - WARN_ON(!pendowner->pi_blocked_on); - WARN_ON(pendowner->pi_blocked_on != waiter); - WARN_ON(pendowner->pi_blocked_on->lock != lock); - - pendowner->pi_blocked_on = NULL; - - if (rt_mutex_has_waiters(lock)) { - struct rt_mutex_waiter *next; - - next = rt_mutex_top_waiter(lock); - plist_add(&next->pi_list_entry, &pendowner->pi_waiters); - } - raw_spin_unlock_irqrestore(&pendowner->pi_lock, flags); - - wake_up_process(pendowner); + wake_up_process(waiter->task); } /* - * Remove a waiter from a lock + * Remove a waiter from a lock and give up * - * Must be called with lock->wait_lock held + * Must be called with lock->wait_lock held and + * have just failed to try_to_take_rt_mutex(). */ static void remove_waiter(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) @@ -543,11 +497,13 @@ static void remove_waiter(struct rt_mutex *lock, raw_spin_lock_irqsave(¤t->pi_lock, flags); plist_del(&waiter->list_entry, &lock->wait_list); - waiter->task = NULL; current->pi_blocked_on = NULL; raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - if (first && owner != current) { + if (!owner) + return; + + if (first) { raw_spin_lock_irqsave(&owner->pi_lock, flags); @@ -614,21 +570,19 @@ void rt_mutex_adjust_pi(struct task_struct *task) * or TASK_UNINTERRUPTIBLE) * @timeout: the pre-initialized and started timer, or NULL for none * @waiter: the pre-initialized rt_mutex_waiter - * @detect_deadlock: passed to task_blocks_on_rt_mutex * * lock->wait_lock must be held by the caller. */ static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, int state, struct hrtimer_sleeper *timeout, - struct rt_mutex_waiter *waiter, - int detect_deadlock) + struct rt_mutex_waiter *waiter) { int ret = 0; for (;;) { /* Try to acquire the lock: */ - if (try_to_take_rt_mutex(lock)) + if (try_to_take_rt_mutex(lock, current, waiter)) break; /* @@ -645,39 +599,11 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state, break; } - /* - * waiter->task is NULL the first time we come here and - * when we have been woken up by the previous owner - * but the lock got stolen by a higher prio task. - */ - if (!waiter->task) { - ret = task_blocks_on_rt_mutex(lock, waiter, current, - detect_deadlock); - /* - * If we got woken up by the owner then start loop - * all over without going into schedule to try - * to get the lock now: - */ - if (unlikely(!waiter->task)) { - /* - * Reset the return value. We might - * have returned with -EDEADLK and the - * owner released the lock while we - * were walking the pi chain. - */ - ret = 0; - continue; - } - if (unlikely(ret)) - break; - } - raw_spin_unlock(&lock->wait_lock); debug_rt_mutex_print_deadlock(waiter); - if (waiter->task) - schedule_rt_mutex(lock); + schedule_rt_mutex(lock); raw_spin_lock(&lock->wait_lock); set_current_state(state); @@ -698,12 +624,11 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, int ret = 0; debug_rt_mutex_init_waiter(&waiter); - waiter.task = NULL; raw_spin_lock(&lock->wait_lock); /* Try to acquire the lock again: */ - if (try_to_take_rt_mutex(lock)) { + if (try_to_take_rt_mutex(lock, current, NULL)) { raw_spin_unlock(&lock->wait_lock); return 0; } @@ -717,12 +642,14 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, timeout->task = NULL; } - ret = __rt_mutex_slowlock(lock, state, timeout, &waiter, - detect_deadlock); + ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock); + + if (likely(!ret)) + ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); set_current_state(TASK_RUNNING); - if (unlikely(waiter.task)) + if (unlikely(ret)) remove_waiter(lock, &waiter); /* @@ -737,14 +664,6 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, if (unlikely(timeout)) hrtimer_cancel(&timeout->timer); - /* - * Readjust priority, when we did not get the lock. We might - * have been the pending owner and boosted. Since we did not - * take the lock, the PI boost has to go. - */ - if (unlikely(ret)) - rt_mutex_adjust_prio(current); - debug_rt_mutex_free_waiter(&waiter); return ret; @@ -762,7 +681,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lock) if (likely(rt_mutex_owner(lock) != current)) { - ret = try_to_take_rt_mutex(lock); + ret = try_to_take_rt_mutex(lock, current, NULL); /* * try_to_take_rt_mutex() sets the lock waiters * bit unconditionally. Clean this up. @@ -992,7 +911,7 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock, { __rt_mutex_init(lock, NULL); debug_rt_mutex_proxy_lock(lock, proxy_owner); - rt_mutex_set_owner(lock, proxy_owner, 0); + rt_mutex_set_owner(lock, proxy_owner); rt_mutex_deadlock_account_lock(lock, proxy_owner); } @@ -1008,7 +927,7 @@ void rt_mutex_proxy_unlock(struct rt_mutex *lock, struct task_struct *proxy_owner) { debug_rt_mutex_proxy_unlock(lock); - rt_mutex_set_owner(lock, NULL, 0); + rt_mutex_set_owner(lock, NULL); rt_mutex_deadlock_account_unlock(proxy_owner); } @@ -1034,20 +953,14 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock, raw_spin_lock(&lock->wait_lock); - mark_rt_mutex_waiters(lock); - - if (!rt_mutex_owner(lock) || try_to_steal_lock(lock, task)) { - /* We got the lock for task. */ - debug_rt_mutex_lock(lock); - rt_mutex_set_owner(lock, task, 0); + if (try_to_take_rt_mutex(lock, task, NULL)) { raw_spin_unlock(&lock->wait_lock); - rt_mutex_deadlock_account_lock(lock, task); return 1; } ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock); - if (ret && !waiter->task) { + if (ret && !rt_mutex_owner(lock)) { /* * Reset the return value. We might have * returned with -EDEADLK and the owner @@ -1056,6 +969,10 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock, */ ret = 0; } + + if (unlikely(ret)) + remove_waiter(lock, waiter); + raw_spin_unlock(&lock->wait_lock); debug_rt_mutex_print_deadlock(waiter); @@ -1110,12 +1027,11 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, set_current_state(TASK_INTERRUPTIBLE); - ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, - detect_deadlock); + ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); set_current_state(TASK_RUNNING); - if (unlikely(waiter->task)) + if (unlikely(ret)) remove_waiter(lock, waiter); /* @@ -1126,13 +1042,5 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, raw_spin_unlock(&lock->wait_lock); - /* - * Readjust priority, when we did not get the lock. We might have been - * the pending owner and boosted. Since we did not take the lock, the - * PI boost has to go. - */ - if (unlikely(ret)) - rt_mutex_adjust_prio(current); - return ret; } diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h index 97a2f81..53a66c8 100644 --- a/kernel/rtmutex_common.h +++ b/kernel/rtmutex_common.h @@ -91,9 +91,8 @@ task_top_pi_waiter(struct task_struct *p) /* * lock->owner state tracking: */ -#define RT_MUTEX_OWNER_PENDING 1UL -#define RT_MUTEX_HAS_WAITERS 2UL -#define RT_MUTEX_OWNER_MASKALL 3UL +#define RT_MUTEX_HAS_WAITERS 1UL +#define RT_MUTEX_OWNER_MASKALL 1UL static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock) { @@ -101,17 +100,6 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock) ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL); } -static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock) -{ - return (struct task_struct *) - ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); -} - -static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock) -{ - return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING; -} - /* * PI-futex support (proxy locking functions, etc.): */ diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 77e9166..3547699 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -699,7 +699,8 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->nr_running--; } -#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED +#ifdef CONFIG_FAIR_GROUP_SCHED +# ifdef CONFIG_SMP static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq, int global_update) { @@ -762,6 +763,51 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) list_del_leaf_cfs_rq(cfs_rq); } +static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg, + long weight_delta) +{ + long load_weight, load, shares; + + load = cfs_rq->load.weight + weight_delta; + + load_weight = atomic_read(&tg->load_weight); + load_weight -= cfs_rq->load_contribution; + load_weight += load; + + shares = (tg->shares * load); + if (load_weight) + shares /= load_weight; + + if (shares < MIN_SHARES) + shares = MIN_SHARES; + if (shares > tg->shares) + shares = tg->shares; + + return shares; +} + +static void update_entity_shares_tick(struct cfs_rq *cfs_rq) +{ + if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) { + update_cfs_load(cfs_rq, 0); + update_cfs_shares(cfs_rq, 0); + } +} +# else /* CONFIG_SMP */ +static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) +{ +} + +static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg, + long weight_delta) +{ + return tg->shares; +} + +static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq) +{ +} +# endif /* CONFIG_SMP */ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, unsigned long weight) { @@ -782,7 +828,7 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta) { struct task_group *tg; struct sched_entity *se; - long load_weight, load, shares; + long shares; if (!cfs_rq) return; @@ -791,32 +837,14 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta) se = tg->se[cpu_of(rq_of(cfs_rq))]; if (!se) return; - - load = cfs_rq->load.weight + weight_delta; - - load_weight = atomic_read(&tg->load_weight); - load_weight -= cfs_rq->load_contribution; - load_weight += load; - - shares = (tg->shares * load); - if (load_weight) - shares /= load_weight; - - if (shares < MIN_SHARES) - shares = MIN_SHARES; - if (shares > tg->shares) - shares = tg->shares; +#ifndef CONFIG_SMP + if (likely(se->load.weight == tg->shares)) + return; +#endif + shares = calc_cfs_shares(cfs_rq, tg, weight_delta); reweight_entity(cfs_rq_of(se), se, shares); } - -static void update_entity_shares_tick(struct cfs_rq *cfs_rq) -{ - if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) { - update_cfs_load(cfs_rq, 0); - update_cfs_shares(cfs_rq, 0); - } -} #else /* CONFIG_FAIR_GROUP_SCHED */ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update) { diff --git a/kernel/sysctl.c b/kernel/sysctl.c index bc86bb3..0f1bd83 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -170,7 +170,8 @@ static int proc_taint(struct ctl_table *table, int write, #endif #ifdef CONFIG_MAGIC_SYSRQ -static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */ +/* Note: sysrq code uses it's own private copy */ +static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE; static int sysrq_sysctl_handler(ctl_table *table, int write, void __user *buffer, size_t *lenp, diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 3e216e0..c55ea24 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -642,8 +642,7 @@ static void tick_nohz_switch_to_nohz(void) } local_irq_enable(); - printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", - smp_processor_id()); + printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id()); } /* @@ -795,8 +794,10 @@ void tick_setup_sched_timer(void) } #ifdef CONFIG_NO_HZ - if (tick_nohz_enabled) + if (tick_nohz_enabled) { ts->nohz_mode = NOHZ_MODE_HIGHRES; + printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id()); + } #endif } #endif /* HIGH_RES_TIMERS */ |