From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757298Ab2HNSMe (ORCPT ); Tue, 14 Aug 2012 14:12:34 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:51602 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757222Ab2HNSLm (ORCPT ); Tue, 14 Aug 2012 14:11:42 -0400 From: Joonsoo Kim To: Tejun Heo Cc: linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH v2 3/6] workqueue: change value of lcpu in __queue_delayed_work_on() Date: Wed, 15 Aug 2012 03:10:13 +0900 Message-Id: <1344967816-1136-4-git-send-email-js1304@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1344967816-1136-1-git-send-email-js1304@gmail.com> References: <1344967816-1136-1-git-send-email-js1304@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We assign cpu id into work struct's data field in __queue_delayed_work_on(). In current implementation, when work is come in first time, current running cpu id is assigned. If we do __queue_delayed_work_on() with CPU A on CPU B, __queue_work() invoked in delayed_work_timer_fn() go into the following sub-optimal path in case of WQ_NON_REENTRANT. gcwq = get_gcwq(cpu); if (wq->flags & WQ_NON_REENTRANT && (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) { Change lcpu to @cpu and rechange lcpu to local cpu if lcpu is WORK_CPU_UNBOUND. It is sufficient to prevent to go into sub-optimal path. Signed-off-by: Joonsoo Kim diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 6a17ab0..f55ac26 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1358,9 +1358,10 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, if (!(wq->flags & WQ_UNBOUND)) { struct global_cwq *gcwq = get_work_gcwq(work); - if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND) + lcpu = cpu; + if (gcwq) lcpu = gcwq->cpu; - else + if (lcpu == WORK_CPU_UNBOUND) lcpu = raw_smp_processor_id(); } else { lcpu = WORK_CPU_UNBOUND; -- 1.7.9.5