From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752427AbcEYIV1 (ORCPT ); Wed, 25 May 2016 04:21:27 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:52763 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750797AbcEYIVY (ORCPT ); Wed, 25 May 2016 04:21:24 -0400 X-IBM-Helo: d23dlp01.au.ibm.com X-IBM-MailFrom: xinhui.pan@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org 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, jeremy@goop.org, chrisw@sous-sol.org, akataria@vmware.com, rusty@rustcorp.com.au, Pan Xinhui Subject: [PATCH v3 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock Date: Wed, 25 May 2016 16:18:08 +0800 Message-Id: <1464164289-6124-6-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16052508-0021-0000-0000-000009BA3018 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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; -- 1.9.1