From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7852) id 7C5683857404; Wed, 28 Sep 2022 16:06:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7C5683857404 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1664381169; bh=KsRX/hv9oO/gcHjhC0GyLlOCzSOA7HTP9sLQ14aZLG4=; h=From:To:Subject:Date:From; b=gp3j5cM8rFq9NSzBQHqZh6v7gjGlX4jFKFaiA6SZrQh7zI5UO1/Bjs3Sxzz33BG/1 5gnBVQYWRgRx7R+lmjy4frSM+1uUmdwYDlzX4OS8gJdN1I5nzO08ApNBfEzblxcceT 3Nxs0YhaHo8zuDykVnWJlipKC4Be0tE5t5Ud3LjU= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Sunil Pandey To: glibc-cvs@sourceware.org Subject: [glibc/release/2.34/master] Move assignment out of the CAS condition X-Act-Checkin: glibc X-Git-Author: H.J. Lu X-Git-Refname: refs/heads/release/2.34/master X-Git-Oldrev: a6b81f605dfba8650ea1f80122f41eb8e6c73dc7 X-Git-Newrev: 6bcfbee7277e4faa4b693bd965931f0d1883005d Message-Id: <20220928160609.7C5683857404@sourceware.org> Date: Wed, 28 Sep 2022 16:06:09 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6bcfbee7277e4faa4b693bd965931f0d1883005d commit 6bcfbee7277e4faa4b693bd965931f0d1883005d Author: H.J. Lu Date: Fri Nov 12 11:47:42 2021 -0800 Move assignment out of the CAS condition Update commit 49302b8fdf9103b6fc0a398678668a22fa19574c Author: H.J. Lu 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 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. (cherry picked from commit 120ac6d238825452e8024e2f627da33b2508dfd3) Diff: --- 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 9f40928cc6..49901ffa0a 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -305,10 +305,9 @@ __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 90cede9446..2e5506db06 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -234,10 +234,9 @@ __pthread_mutex_clocklock_common (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;