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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-11-11 06:31:51 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-11-12 10:30:57 -0800 |
| commit | 0b82747dc48d5bf0871bdc6da8cb6eec1256355f (patch) | |
| tree | 323e1555048a99c28508090d656b2dccd199b61d /nptl | |
| parent | 6c1e3c0fd09a9653f562db69e77281e358451163 (diff) | |
| download | glibc-0b82747dc48d5bf0871bdc6da8cb6eec1256355f.zip glibc-0b82747dc48d5bf0871bdc6da8cb6eec1256355f.tar.gz glibc-0b82747dc48d5bf0871bdc6da8cb6eec1256355f.tar.bz2 | |
Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Diffstat (limited to 'nptl')
| -rw-r--r-- | nptl/pthread_mutex_lock.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index 2bd4176..59a28cf 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -297,12 +297,12 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) meantime. */ if ((oldval & FUTEX_WAITERS) == 0) { - if (atomic_compare_and_exchange_bool_acq (&mutex->__data.__lock, - oldval | FUTEX_WAITERS, - oldval) - != 0) + int val; + if ((val = atomic_compare_and_exchange_val_acq + (&mutex->__data.__lock, oldval | FUTEX_WAITERS, + oldval)) != oldval) { - oldval = mutex->__data.__lock; + oldval = val; continue; } oldval |= FUTEX_WAITERS; |