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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 2B434C3B185 for ; Mon, 17 Feb 2020 10:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C17C2464E for ; Mon, 17 Feb 2020 10:44:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729405AbgBQKo4 (ORCPT ); Mon, 17 Feb 2020 05:44:56 -0500 Received: from outbound-smtp47.blacknight.com ([46.22.136.64]:51129 "EHLO outbound-smtp47.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727332AbgBQKo4 (ORCPT ); Mon, 17 Feb 2020 05:44:56 -0500 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp47.blacknight.com (Postfix) with ESMTPS id 9BC20FAB5A for ; Mon, 17 Feb 2020 10:44:53 +0000 (GMT) Received: (qmail 26696 invoked from network); 17 Feb 2020 10:44:53 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.18.57]) by 81.17.254.9 with ESMTPA; 17 Feb 2020 10:44:53 -0000 From: Mel Gorman To: Peter Zijlstra Cc: Ingo Molnar , Vincent Guittot , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Valentin Schneider , Phil Auld , Hillf Danton , LKML , Mel Gorman Subject: [PATCH 04/13] sched/fair: Reorder enqueue/dequeue_task_fair path Date: Mon, 17 Feb 2020 10:43:53 +0000 Message-Id: <20200217104402.11643-5-mgorman@techsingularity.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200217104402.11643-1-mgorman@techsingularity.net> References: <20200217104402.11643-1-mgorman@techsingularity.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vincent Guittot 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 No functional and performance changes are expected and have been noticed during tests. Signed-off-by: Vincent Guittot Signed-off-by: Mel Gorman --- 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 6c866fb2129c..4395951b1530 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5261,32 +5261,31 @@ 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); /* @@ -5347,17 +5346,13 @@ 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: */ @@ -5375,16 +5370,19 @@ 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); -- 2.16.4