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authorH.J. Lu <hjl.tools@gmail.com>2021-11-11 06:54:01 -0800
committerH.J. Lu <hjl.tools@gmail.com>2021-11-12 10:31:31 -0800
commit49302b8fdf9103b6fc0a398678668a22fa19574c (patch)
tree1b06b2062260382deeea33957e840e6792fa23eb /nptl
parent0b82747dc48d5bf0871bdc6da8cb6eec1256355f (diff)
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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 <szabolcs.nagy@arm.com>
Diffstat (limited to 'nptl')
-rw-r--r--nptl/pthread_mutex_timedlock.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index 57f3f28869..f763cfc7fa 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -233,12 +233,12 @@ __pthread_mutex_clocklock_common (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;