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author | Pierre Peiffer <pierre.peiffer@bull.net> | 2007-05-09 02:35:02 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:55 -0700 |
commit | d0aa7a70bf03b9de9e995ab272293be1f7937822 (patch) | |
tree | 194b30b7b8374b946f166996cb99fb95eb3b7819 /kernel/rtmutex_common.h | |
parent | c19384b5b296905d4988c7c684ff540a0f9d65be (diff) | |
download | kernel_samsung_tuna-d0aa7a70bf03b9de9e995ab272293be1f7937822.zip kernel_samsung_tuna-d0aa7a70bf03b9de9e995ab272293be1f7937822.tar.gz kernel_samsung_tuna-d0aa7a70bf03b9de9e995ab272293be1f7937822.tar.bz2 |
futex_requeue_pi optimization
This patch provides the futex_requeue_pi functionality, which allows some
threads waiting on a normal futex to be requeued on the wait-queue of a
PI-futex.
This provides an optimization, already used for (normal) futexes, to be used
with the PI-futexes.
This optimization is currently used by the glibc in pthread_broadcast, when
using "normal" mutexes. With futex_requeue_pi, it can be used with
PRIO_INHERIT mutexes too.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/rtmutex_common.h')
-rw-r--r-- | kernel/rtmutex_common.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h index 9c75856..242ec7e 100644 --- a/kernel/rtmutex_common.h +++ b/kernel/rtmutex_common.h @@ -113,6 +113,29 @@ static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock) } /* + * We can speed up the acquire/release, if the architecture + * supports cmpxchg and if there's no debugging state to be set up + */ +#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES) +# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c) +static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +{ + unsigned long owner, *p = (unsigned long *) &lock->owner; + + do { + owner = *p; + } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner); +} +#else +# define rt_mutex_cmpxchg(l,c,n) (0) +static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +{ + lock->owner = (struct task_struct *) + ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); +} +#endif + +/* * PI-futex support (proxy locking functions, etc.): */ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock); @@ -120,4 +143,15 @@ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock, struct task_struct *proxy_owner); extern void rt_mutex_proxy_unlock(struct rt_mutex *lock, struct task_struct *proxy_owner); + +extern void rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner, + unsigned long mask); +extern void __rt_mutex_adjust_prio(struct task_struct *task); +extern int rt_mutex_adjust_prio_chain(struct task_struct *task, + int deadlock_detect, + struct rt_mutex *orig_lock, + struct rt_mutex_waiter *orig_waiter, + struct task_struct *top_task); +extern void remove_waiter(struct rt_mutex *lock, + struct rt_mutex_waiter *waiter); #endif |