From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E832AC38A2B for ; Fri, 17 Apr 2020 14:50:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3AC42223D for ; Fri, 17 Apr 2020 14:50:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728229AbgDQOuv (ORCPT ); Fri, 17 Apr 2020 10:50:51 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:57169 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727877AbgDQOuu (ORCPT ); Fri, 17 Apr 2020 10:50:50 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0TvqJzQo_1587135046; Received: from localhost(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0TvqJzQo_1587135046) by smtp.aliyun-inc.com(127.0.0.1); Fri, 17 Apr 2020 22:50:47 +0800 From: Alex Shi Cc: Alex Shi , Thomas Gleixner , Davidlohr Bueso , Ingo Molnar , Will Deacon , linux-kernel@vger.kernel.org Subject: [PATCH 2/2] locking/rtmutex: optimize rt_mutex_cmpxchgs Date: Fri, 17 Apr 2020 22:50:32 +0800 Message-Id: <1587135032-188866-2-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1587135032-188866-1-git-send-email-alex.shi@linux.alibaba.com> References: <1587135032-188866-1-git-send-email-alex.shi@linux.alibaba.com> To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Checking l->owner first to skip time cost cmpxchgs. Suggested-by: Davidlohr Bueso Signed-off-by: Alex Shi Cc: Thomas Gleixner Cc: Davidlohr Bueso Cc: Ingo Molnar Cc: Will Deacon Cc: linux-kernel@vger.kernel.org --- kernel/locking/rtmutex.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index cfdd5b93264d..232727a4a220 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -141,8 +141,10 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock) * set up. */ #ifndef CONFIG_DEBUG_RT_MUTEXES -# define rt_mutex_cmpxchg_acquire(l,c,n) (cmpxchg_acquire(&l->owner, c, n) == c) -# define rt_mutex_cmpxchg_release(l,c,n) (cmpxchg_release(&l->owner, c, n) == c) +# define rt_mutex_cmpxchg_acquire(l, c, n) \ + (l->owner == c && cmpxchg_acquire(&l->owner, c, n) == c) +# define rt_mutex_cmpxchg_release(l, c, n) \ + (l->owner == c && cmpxchg_release(&l->owner, c, n) == c) /* * Callers must hold the ->wait_lock -- which is the whole purpose as we force -- 1.8.3.1