From 56212a35fe258f45f242f4bb80866e4980e4ec0e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 11 Nov 2021 06:54:01 -0800 Subject: [PATCH] Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537] Replace boolean CAS with value CAS to avoid the extra load. Reviewed-by: Szabolcs Nagy (cherry picked from commit 49302b8fdf9103b6fc0a398678668a22fa19574c) --- nptl/pthread_mutex_timedlock.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index 888c12fe..c4627ef6 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -269,12 +269,12 @@ __pthread_mutex_timedlock (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; -- GitLab