From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753468AbdBPCe5 (ORCPT ); Wed, 15 Feb 2017 21:34:57 -0500 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:46015 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753162AbdBPCeo (ORCPT ); Wed, 15 Feb 2017 21:34:44 -0500 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 165.244.249.25 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: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Date: Thu, 16 Feb 2017 11:34:17 +0900 Message-ID: <1487212457-28839-2-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1487212457-28839-1-git-send-email-byungchul.park@lge.com> References: <1487212457-28839-1-git-send-email-byungchul.park@lge.com> X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB01/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/02/16 11:34:40, Serialize by Router on LGEKRMHUB01/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/02/16 11:34:40, Serialize complete at 2017/02/16 11:34:40 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_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 --- kernel/sched/rt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 4101f9d..5abd9a52 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1820,7 +1820,7 @@ static int push_rt_task(struct rq *rq) * pushing. */ task = pick_next_pushable_task(rq); - if (task_cpu(next_task) == rq->cpu && task == next_task) { + if (task == next_task) { /* * The task hasn't migrated, and is still the next * eligible task, but we failed to find a run-queue -- 1.9.1