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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 4B29CC11D2F for ; Mon, 24 Feb 2020 15:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2839220714 for ; Mon, 24 Feb 2020 15:21:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727984AbgBXPUr (ORCPT ); Mon, 24 Feb 2020 10:20:47 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:50323 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727796AbgBXPUq (ORCPT ); Mon, 24 Feb 2020 10:20:46 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j6FX7-0005tv-QC; Mon, 24 Feb 2020 16:20:33 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 67FD01C213A; Mon, 24 Feb 2020 16:20:33 +0100 (CET) Date: Mon, 24 Feb 2020 15:20:33 -0000 From: "tip-bot2 for Vincent Guittot" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Reorder enqueue/dequeue_task_fair path Cc: Vincent Guittot , Mel Gorman , Ingo Molnar , "Dietmar Eggemann" , Peter Zijlstra , Juri Lelli , Valentin Schneider , Phil Auld , Hillf Danton , x86 , LKML In-Reply-To: <20200224095223.13361-5-mgorman@techsingularity.net> References: <20200224095223.13361-5-mgorman@techsingularity.net> MIME-Version: 1.0 Message-ID: <158255763308.28353.12582539740202499085.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 6d4d22468dae3d8757af9f8b81b848a76ef4409d Gitweb: https://git.kernel.org/tip/6d4d22468dae3d8757af9f8b81b848a76ef4409d Author: Vincent Guittot AuthorDate: Mon, 24 Feb 2020 09:52:14 Committer: Ingo Molnar CommitterDate: Mon, 24 Feb 2020 11:36:34 +01:00 sched/fair: Reorder enqueue/dequeue_task_fair path The walk through the cgroup hierarchy during the enqueue/dequeue of a task is split in 2 distinct parts for throttled cfs_rq without any added value but making code less readable. Change the code ordering such that everything related to a cfs_rq (throttled or not) will be done in the same loop. In addition, the same steps ordering is used when updating a cfs_rq: - update_load_avg - update_cfs_group - update *h_nr_running This reordering enables the use of h_nr_running in PELT algorithm. No functional and performance changes are expected and have been noticed during tests. Signed-off-by: Vincent Guittot Signed-off-by: Mel Gorman Signed-off-by: Ingo Molnar Reviewed-by: "Dietmar Eggemann " Acked-by: Peter Zijlstra Cc: Juri Lelli Cc: Valentin Schneider Cc: Phil Auld Cc: Hillf Danton Link: https://lore.kernel.org/r/20200224095223.13361-5-mgorman@techsingularity.net --- kernel/sched/fair.c | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5d9c23c..a6c7f8b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5260,32 +5260,31 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) cfs_rq = cfs_rq_of(se); enqueue_entity(cfs_rq, se, flags); - /* - * end evaluation on encountering a throttled cfs_rq - * - * note: in the case of encountering a throttled cfs_rq we will - * post the final h_nr_running increment below. - */ - if (cfs_rq_throttled(cfs_rq)) - break; cfs_rq->h_nr_running++; cfs_rq->idle_h_nr_running += idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ + if (cfs_rq_throttled(cfs_rq)) + goto enqueue_throttle; + flags = ENQUEUE_WAKEUP; } for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); - cfs_rq->h_nr_running++; - cfs_rq->idle_h_nr_running += idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) - break; + goto enqueue_throttle; update_load_avg(cfs_rq, se, UPDATE_TG); update_cfs_group(se); + + cfs_rq->h_nr_running++; + cfs_rq->idle_h_nr_running += idle_h_nr_running; } +enqueue_throttle: if (!se) { add_nr_running(rq, 1); /* @@ -5346,17 +5345,13 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) cfs_rq = cfs_rq_of(se); dequeue_entity(cfs_rq, se, flags); - /* - * end evaluation on encountering a throttled cfs_rq - * - * note: in the case of encountering a throttled cfs_rq we will - * post the final h_nr_running decrement below. - */ - if (cfs_rq_throttled(cfs_rq)) - break; cfs_rq->h_nr_running--; cfs_rq->idle_h_nr_running -= idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ + if (cfs_rq_throttled(cfs_rq)) + goto dequeue_throttle; + /* Don't dequeue parent if it has other entities besides us */ if (cfs_rq->load.weight) { /* Avoid re-evaluating load for this entity: */ @@ -5374,16 +5369,19 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); - cfs_rq->h_nr_running--; - cfs_rq->idle_h_nr_running -= idle_h_nr_running; + /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) - break; + goto dequeue_throttle; update_load_avg(cfs_rq, se, UPDATE_TG); update_cfs_group(se); + + cfs_rq->h_nr_running--; + cfs_rq->idle_h_nr_running -= idle_h_nr_running; } +dequeue_throttle: if (!se) sub_nr_running(rq, 1);