diff options
| author | Ulrich Drepper <drepper@redhat.com> | 2001-05-24 07:25:43 +0000 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2001-05-24 07:25:43 +0000 |
| commit | 9c4a51972f5de318f3786938949b8320a385fef1 (patch) | |
| tree | 54cb92794d8a11e75a11114b4acacc2532e75109 /linuxthreads/mutex.c | |
| parent | 64b7897d6d453e67afe3f9d81c8fc37c26f8d483 (diff) | |
| download | glibc-9c4a51972f5de318f3786938949b8320a385fef1.tar.gz | |
Update.
2001-05-01 Kaz Kylheku <kaz@ashi.footprints.net>
Memory barrier overhaul following line by line inspection.
* mutex.c (pthread_once): Missing memory barriers added.
* pthread.c (__pthread_wait_for_restart_signal,
__pthread_timedsuspend_new, __pthread_restart_new): Added
memory barriers ``just in case'' and for documentary value.
* spinlock.c (__pthread_release): New inline function for releasing
spinlock, to complement __pthread_acquire. Includes memory
barrier prior to assignment to spinlock, and __asm __volatile
dance to prevent reordering or optimization of the spinlock access.
* spinlock.c (__pthread_unlock, __pthread_alt_lock,
__pthread_alt_timedlock, __pthread_alt_unlock,
__pthread_compare_and_swap): Updated to use new __pthread_release
instead of updating spinlock directly.
* spinlock.c (__pthread_lock, __pthread_unlock, wait_node_alloc,
wait_node_free, wait_node_dequeue, __pthread_alt_lock,
__pthread_alt_timedlock, __pthread_alt_unlock, __pthread_acquire):
Memory barrier overhaul. Lots of missing memory barriers added,
a couple needless ones removed.
* spinlock.c (__pthread_compare_and_swap): testandset optimization
removed, just calls __pthread_acquire, which has the new read
barrier in it before its testandset.
Diffstat (limited to 'linuxthreads/mutex.c')
| -rw-r--r-- | linuxthreads/mutex.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/linuxthreads/mutex.c b/linuxthreads/mutex.c index 3ad27942af..3c97ea7d66 100644 --- a/linuxthreads/mutex.c +++ b/linuxthreads/mutex.c @@ -285,7 +285,10 @@ int __pthread_once(pthread_once_t * once_control, void (*init_routine)(void)) int state_changed; /* Test without locking first for speed */ - if (*once_control == DONE) return 0; + if (*once_control == DONE) { + READ_MEMORY_BARRIER(); + return 0; + } /* Lock and test again */ state_changed = 0; @@ -310,6 +313,7 @@ int __pthread_once(pthread_once_t * once_control, void (*init_routine)(void)) init_routine(); pthread_cleanup_pop(0); pthread_mutex_lock(&once_masterlock); + WRITE_MEMORY_BARRIER(); *once_control = DONE; state_changed = 1; } |