glibc/SOURCES/glibc-RHEL-15696-67.patch

72 lines
2.2 KiB
Diff

From 120ac6d238825452e8024e2f627da33b2508dfd3 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 12 Nov 2021 11:47:42 -0800
Subject: [PATCH] Move assignment out of the CAS condition
Content-type: text/plain; charset=UTF-8
Update
commit 49302b8fdf9103b6fc0a398678668a22fa19574c
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Nov 11 06:54:01 2021 -0800
Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.
and
commit 0b82747dc48d5bf0871bdc6da8cb6eec1256355f
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Thu Nov 11 06:31:51 2021 -0800
Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.
by moving assignment out of the CAS condition.
---
nptl/pthread_mutex_lock.c | 7 +++----
nptl/pthread_mutex_timedlock.c | 7 +++----
2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
index eb4d8baa..a633d95e 100644
--- a/nptl/pthread_mutex_lock.c
+++ b/nptl/pthread_mutex_lock.c
@@ -299,10 +299,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
meantime. */
if ((oldval & FUTEX_WAITERS) == 0)
{
- int val;
- if ((val = atomic_compare_and_exchange_val_acq
- (&mutex->__data.__lock, oldval | FUTEX_WAITERS,
- oldval)) != oldval)
+ int val = atomic_compare_and_exchange_val_acq
+ (&mutex->__data.__lock, oldval | FUTEX_WAITERS, oldval);
+ if (val != oldval)
{
oldval = val;
continue;
diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index c4627ef6..a76c30b7 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -269,10 +269,9 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
meantime. */
if ((oldval & FUTEX_WAITERS) == 0)
{
- int val;
- if ((val = atomic_compare_and_exchange_val_acq
- (&mutex->__data.__lock, oldval | FUTEX_WAITERS,
- oldval)) != oldval)
+ int val = atomic_compare_and_exchange_val_acq
+ (&mutex->__data.__lock, oldval | FUTEX_WAITERS, oldval);
+ if (val != oldval)
{
oldval = val;
continue;
--
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