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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 7B196C3815B for ; Mon, 20 Apr 2020 17:44:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B24220857 for ; Mon, 20 Apr 2020 17:44:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726966AbgDTRog (ORCPT ); Mon, 20 Apr 2020 13:44:36 -0400 Received: from foss.arm.com ([217.140.110.172]:52878 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725784AbgDTRog (ORCPT ); Mon, 20 Apr 2020 13:44:36 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 675BA31B; Mon, 20 Apr 2020 10:44:33 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 03DBB3F73D; Mon, 20 Apr 2020 10:44:31 -0700 (PDT) References: <4f301770996c02f44d52a4868f510025d5a3a558.1587393807.git.yu.c.chen@intel.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Chen Yu Cc: Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2][v2] sched: Extract the task putting code from pick_next_task() In-reply-to: <4f301770996c02f44d52a4868f510025d5a3a558.1587393807.git.yu.c.chen@intel.com> Date: Mon, 20 Apr 2020 18:44:29 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/04/20 16:01, Chen Yu wrote: > Introduce a new function finish_prev_task() to do the balance > when necessary, and then put previous task back to the run queue. > This function is extracted from pick_next_task() to prepare for > future usage by other type of task picking logic. > > No functional change. > With the absolutely tiny nit below: Reviewed-by: Valentin Schneider > Suggested-by: Peter Zijlstra > Signed-off-by: Chen Yu > --- > kernel/sched/core.c | 39 +++++++++++++++++++++++---------------- > 1 file changed, 23 insertions(+), 16 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 3a61a3b8eaa9..bf59a5cf030c 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -3904,6 +3904,28 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt) > schedstat_inc(this_rq()->sched_count); > } > > +static void finish_prev_task(struct rq *rq, struct task_struct *prev, > + struct rq_flags *rf) > +{ > + const struct sched_class *class; > +#ifdef CONFIG_SMP Nit: I would've put that declaration within the ifdef, given it isn't used outside of it. > + /* > + * We must do the balancing pass before put_next_task(), such > + * that when we release the rq->lock the task is in the same > + * state as before we took rq->lock. > + * > + * We can terminate the balance pass as soon as we know there is > + * a runnable task of @class priority or higher. > + */ > + for_class_range(class, prev->sched_class, &idle_sched_class) { > + if (class->balance(rq, prev, rf)) > + break; > + } > +#endif > + > + put_prev_task(rq, prev); > +} > + > /* > * Pick up the highest-prio task: > */