From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rL2ht6pFBzDqy3 for ; Thu, 2 Jun 2016 19:57:50 +1000 (AEST) Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 2 Jun 2016 03:27:39 -0600 From: Pan Xinhui 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, waiman.long@hpe.com, Pan Xinhui Subject: [PATCH v5 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock Date: Thu, 2 Jun 2016 17:26:29 +0800 Message-Id: <1464859590-5292-7-git-send-email-xinhui.pan@linux.vnet.ibm.com> In-Reply-To: <1464859590-5292-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1464859590-5292-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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