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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.c | |
parent | c19384b5b296905d4988c7c684ff540a0f9d65be (diff) | |
download | linux-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.c')
-rw-r--r-- | kernel/rtmutex.c | 41 |
1 files changed, 9 insertions, 32 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 180978cb2f75..12879f6c1ec3 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -56,7 +56,7 @@ * state. */ -static void +void rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner, unsigned long mask) { @@ -81,29 +81,6 @@ static void fixup_rt_mutex_waiters(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 - -/* * Calculate task priority from the waiter list priority * * Return task->normal_prio when the waiter list is empty or when @@ -123,7 +100,7 @@ int rt_mutex_getprio(struct task_struct *task) * * This can be both boosting and unboosting. task->pi_lock must be held. */ -static void __rt_mutex_adjust_prio(struct task_struct *task) +void __rt_mutex_adjust_prio(struct task_struct *task) { int prio = rt_mutex_getprio(task); @@ -159,11 +136,11 @@ int max_lock_depth = 1024; * Decreases task's usage by one - may thus free the task. * Returns 0 or -EDEADLK. */ -static 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) +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) { struct rt_mutex *lock; struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; @@ -524,8 +501,8 @@ static void wakeup_next_waiter(struct rt_mutex *lock) * * Must be called with lock->wait_lock held */ -static void remove_waiter(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter) +void remove_waiter(struct rt_mutex *lock, + struct rt_mutex_waiter *waiter) { int first = (waiter == rt_mutex_top_waiter(lock)); struct task_struct *owner = rt_mutex_owner(lock); |