67 lines
2.2 KiB
Diff
67 lines
2.2 KiB
Diff
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commit 6bcfbee7277e4faa4b693bd965931f0d1883005d
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Author: H.J. Lu <hjl.tools@gmail.com>
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Date: Fri Nov 12 11:47:42 2021 -0800
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Move assignment out of the CAS condition
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Update
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commit 49302b8fdf9103b6fc0a398678668a22fa19574c
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Author: H.J. Lu <hjl.tools@gmail.com>
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Date: Thu Nov 11 06:54:01 2021 -0800
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Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]
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Replace boolean CAS with value CAS to avoid the extra load.
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and
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commit 0b82747dc48d5bf0871bdc6da8cb6eec1256355f
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Author: H.J. Lu <hjl.tools@gmail.com>
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Date: Thu Nov 11 06:31:51 2021 -0800
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Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
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Replace boolean CAS with value CAS to avoid the extra load.
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by moving assignment out of the CAS condition.
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(cherry picked from commit 120ac6d238825452e8024e2f627da33b2508dfd3)
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diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
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index 9f40928cc6b9a067..49901ffa0a96d659 100644
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--- a/nptl/pthread_mutex_lock.c
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+++ b/nptl/pthread_mutex_lock.c
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@@ -305,10 +305,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
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meantime. */
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if ((oldval & FUTEX_WAITERS) == 0)
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{
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- int val;
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- if ((val = atomic_compare_and_exchange_val_acq
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- (&mutex->__data.__lock, oldval | FUTEX_WAITERS,
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- oldval)) != oldval)
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+ int val = atomic_compare_and_exchange_val_acq
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+ (&mutex->__data.__lock, oldval | FUTEX_WAITERS, oldval);
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+ if (val != oldval)
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{
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oldval = val;
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continue;
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diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
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index 90cede9446e33fcf..2e5506db06ccb1ec 100644
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--- a/nptl/pthread_mutex_timedlock.c
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+++ b/nptl/pthread_mutex_timedlock.c
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@@ -234,10 +234,9 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex,
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meantime. */
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if ((oldval & FUTEX_WAITERS) == 0)
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{
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- int val;
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- if ((val = atomic_compare_and_exchange_val_acq
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- (&mutex->__data.__lock, oldval | FUTEX_WAITERS,
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- oldval)) != oldval)
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+ int val = atomic_compare_and_exchange_val_acq
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+ (&mutex->__data.__lock, oldval | FUTEX_WAITERS, oldval);
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+ if (val != oldval)
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{
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oldval = val;
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continue;
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