From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757340AbdELBGG (ORCPT ); Thu, 11 May 2017 21:06:06 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:42471 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753373AbdELBGF (ORCPT ); Thu, 11 May 2017 21:06:05 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 165.244.98.150 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: CC: , Subject: [RESEND PATCH v3] sched/deadline: Remove unnecessary condition in push_dl_task() Date: Fri, 12 May 2017 10:05:59 +0900 Message-ID: <1494551159-22367-1-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB06/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/05/12 10:06:01, Serialize by Router on LGEKRMHUB06/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/05/12 10:06:01, Serialize complete at 2017/05/12 10:06:01 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task)) when it returns a task other than NULL, which means that task_cpu(task) must be rq->cpu. So if task == next_task, then task_cpu(next_task) must be rq->cpu as well. Remove the redundant condition and make code simpler. By this patch, unnecessary one branch and two LOAD operations in 'if' statement can be avoided. Signed-off-by: Byungchul Park Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Juri Lelli Reviewed-by: Daniel Bristot de Oliveira --- kernel/sched/deadline.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 27737f3..ad8d577 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1483,7 +1483,7 @@ static int push_dl_task(struct rq *rq) * then possible that next_task has migrated. */ task = pick_next_pushable_dl_task(rq); - if (task_cpu(next_task) == rq->cpu && task == next_task) { + if (task == next_task) { /* * The task is still there. We don't try * again, some other cpu will pull it when ready. -- 1.9.1