From: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
virtualization@lists.linux-foundation.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
peterz@infradead.org, mingo@redhat.com,
paulmck@linux.vnet.ibm.com, jeremy@goop.org, chrisw@sous-sol.org,
akataria@vmware.com, rusty@rustcorp.com.au,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v3 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock
Date: Wed, 25 May 2016 16:18:08 +0800 [thread overview]
Message-ID: <1464164289-6124-6-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
cmpxchg_release is light-wight than cmpxchg, we can gain a better
performace then. On some arch like ppc, barrier impact the performace
too much.
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
kernel/locking/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index a5b1248..2bbffe4 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -614,7 +614,7 @@ __visible void __pv_queued_spin_unlock(struct qspinlock *lock)
* unhash. Otherwise it would be possible to have multiple @lock
* entries, which would be BAD.
*/
- locked = cmpxchg(&l->locked, _Q_LOCKED_VAL, 0);
+ locked = cmpxchg_release(&l->locked, _Q_LOCKED_VAL, 0);
if (likely(locked == _Q_LOCKED_VAL))
return;
--
1.9.1
next prev parent reply other threads:[~2016-05-25 8:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 8:18 [PATCH v3 0/6] powerpc use pv-qpsinlock as the default spinlock implemention Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 1/6] qspinlock: powerpc support qspinlock Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 2/6] powerpc: pseries/Kconfig: Add qspinlock build config Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 4/6] pv-qspinlock: powerpc support pv-qspinlock Pan Xinhui
2016-05-25 8:18 ` Pan Xinhui [this message]
2016-05-26 16:47 ` [PATCH v3 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock Peter Zijlstra
2016-05-26 16:57 ` Peter Zijlstra
2016-05-27 10:34 ` xinhui
2016-05-25 8:18 ` [PATCH v3 6/6] powerpc: pseries: Add pv-qspinlock build config/make Pan Xinhui
2016-05-26 16:50 ` [PATCH v3 0/6] powerpc use pv-qpsinlock as the default spinlock implemention Peter Zijlstra
2016-05-27 10:52 ` xinhui
2016-05-26 16:54 ` Peter Zijlstra
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