From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751794AbdBOKrx (ORCPT ); Wed, 15 Feb 2017 05:47:53 -0500 Received: from foss.arm.com ([217.140.101.70]:53764 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbdBOKrw (ORCPT ); Wed, 15 Feb 2017 05:47:52 -0500 Date: Wed, 15 Feb 2017 10:47:49 +0000 From: Juri Lelli To: Byungchul Park Cc: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, juri.lelli@gmail.com, kernel-team@lge.com, Steven Rostedt , Luca Abeni Subject: Re: [PATCH] sched/deadline: Remove unnecessary condition in push_dl_task() Message-ID: <20170215104749.GB1368@e106622-lin> References: <1487135511-15817-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1487135511-15817-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+Steve, Luca] Hi, On 15/02/17 14:11, Byungchul Park wrote: > Once pick_next_pushable_dl_task(rq) return a task, it guarantees that > the task's cpu is rq->cpu, so task_cpu(next_task) is always rq->cpu if > task == next_task. Remove a redundant condition and make code simpler. > > Signed-off-by: Byungchul Park > --- > 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) { Seems a sensible optimization to me. Actually, we are doing the same for rt.c; Steve, Peter, do you think we should optimize that as well? Thanks, - Juri