From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pan Xinhui Subject: [PATCH v5 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock Date: Thu, 2 Jun 2016 17:22:49 +0800 Message-ID: <1464859370-5162-7-git-send-email-xinhui.pan__35148.7235901461$1464859538$gmane$org@linux.vnet.ibm.com> References: <1464859370-5162-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1464859370-5162-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.orgv, virtualization@lists.linux-foundation.org Cc: Pan Xinhui , peterz@infradead.org, benh@kernel.crashing.org, waiman.long@hpe.com, mingo@redhat.com, paulus@samba.org, mpe@ellerman.id.au, paulmck@linux.vnet.ibm.com List-Id: virtualization@lists.linuxfoundation.org cmpxchg_release is light-wight than cmpxchg, On some arch like ppc, barrier impact the performace too much. Suggested-by: Boqun Feng Signed-off-by: Pan Xinhui --- 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; -- 2.4.11