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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD763C43334 for ; Thu, 14 Jul 2022 12:32:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239352AbiGNMcA (ORCPT ); Thu, 14 Jul 2022 08:32:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230228AbiGNMbm (ORCPT ); Thu, 14 Jul 2022 08:31:42 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E55C258847 for ; Thu, 14 Jul 2022 05:30:51 -0700 (PDT) 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 0390913D5; Thu, 14 Jul 2022 05:30:52 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 53F323F792; Thu, 14 Jul 2022 05:30:50 -0700 (PDT) Message-ID: <8025988d-7d1d-0b4a-6eed-8b3698bc9bad@arm.com> Date: Thu, 14 Jul 2022 14:30:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v2 03/10] sched/fair: maintain task se depth in set_task_rq() Content-Language: en-US To: Chengming Zhou , mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org References: <20220713040430.25778-1-zhouchengming@bytedance.com> <20220713040430.25778-4-zhouchengming@bytedance.com> From: Dietmar Eggemann In-Reply-To: <20220713040430.25778-4-zhouchengming@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/07/2022 06:04, Chengming Zhou wrote: > Previously we only maintain task se depth in task_move_group_fair(), > if a !fair task change task group, its se depth will not be updated, > so commit eb7a59b2c888 ("sched/fair: Reset se-depth when task switched to FAIR") > fix the problem by updating se depth in switched_to_fair() too. Maybe it's worth mentioning how the se.depth setting from task_move_group_fair() and switched_to_fair() went into attach_task_cfs_rq() with commit daa59407b558 ("sched/fair: Unify switched_{from,to}_fair() and task_move_group_fair()"} and further into attach_entity_cfs_rq() with commit df217913e72e ("sched/fair: Factorize attach/detach entity"). > This patch move task se depth maintainence to set_task_rq(), which will be > called when CPU/cgroup change, so its depth will always be correct. > > This patch is preparation for the next patch. > > Signed-off-by: Chengming Zhou Reviewed-by: Dietmar Eggemann > --- > kernel/sched/fair.c | 8 -------- > kernel/sched/sched.h | 1 + > 2 files changed, 1 insertion(+), 8 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 2a3e12ead144..bf595b622656 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -11539,14 +11539,6 @@ static void attach_entity_cfs_rq(struct sched_entity *se) > { > struct cfs_rq *cfs_rq = cfs_rq_of(se); > > -#ifdef CONFIG_FAIR_GROUP_SCHED > - /* > - * Since the real-depth could have been changed (only FAIR > - * class maintain depth value), reset depth properly. > - */ > - se->depth = se->parent ? se->parent->depth + 1 : 0; > -#endif > - > /* Synchronize entity with its cfs_rq */ > update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); > attach_entity_load_avg(cfs_rq, se); > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index aad7f5ee9666..8cc3eb7b86cd 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1940,6 +1940,7 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) > set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]); > p->se.cfs_rq = tg->cfs_rq[cpu]; > p->se.parent = tg->se[cpu]; > + p->se.depth = tg->se[cpu] ? tg->se[cpu]->depth + 1 : 0; > #endif > > #ifdef CONFIG_RT_GROUP_SCHED