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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 5885BC28CF6 for ; Fri, 3 Aug 2018 14:05:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06B0521709 for ; Fri, 3 Aug 2018 14:05:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06B0521709 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732287AbeHCQCT (ORCPT ); Fri, 3 Aug 2018 12:02:19 -0400 Received: from foss.arm.com ([217.140.101.70]:43314 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731699AbeHCQCT (ORCPT ); Fri, 3 Aug 2018 12:02:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C29F980D; Fri, 3 Aug 2018 07:05:49 -0700 (PDT) Received: from e107985-lin.Emea.Arm.com (e107985-lin.emea.arm.com [10.4.12.239]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 497FC3F2EA; Fri, 3 Aug 2018 07:05:48 -0700 (PDT) From: Dietmar Eggemann To: Peter Zijlstra , Ingo Molnar Cc: Vincent Guittot , Morten Rasmussen , Patrick Bellasi , Quentin Perret , Joel Fernandes , linux-kernel@vger.kernel.org Subject: [PATCH v2] sched/fair: Remove setting task's se->runnable_weight during PELT update Date: Fri, 3 Aug 2018 15:05:38 +0100 Message-Id: <20180803140538.1178-1-dietmar.eggemann@arm.com> X-Mailer: git-send-email 2.11.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A CFS (SCHED_OTHER, SCHED_BATCH or SCHED_IDLE policy) task's se->runnable_weight must always be in sync with its se->load.weight. se->runnable_weight is set to se->load.weight when the task is forked (init_entity_runnable_average()) or reniced (reweight_entity()). There are two cases in set_load_weight() which since they currently only set se->load.weight could lead to a situation in which se->load.weight is different to se->runnable_weight for a CFS task: (1) A task switches to SCHED_IDLE. (2) A SCHED_FIFO, SCHED_RR or SCHED_DEADLINE task which has been reniced (during which only its static priority gets set) switches to SCHED_OTHER or SCHED_BATCH. Set se->runnable_weight to se->load.weight in these two cases to prevent this. This eliminates the need to explicitly set it to se->load.weight during PELT updates in the CFS scheduler fastpath. Signed-off-by: Dietmar Eggemann --- Changes v1->v2: - Rebased on latest tip/sched/core This patch has been tested w/ appropriate BUG_ON()'s in __update_load_avg_blocked_se() and __update_load_avg_se() on an Ubuntu 18.04 desktop. kernel/sched/core.c | 2 ++ kernel/sched/pelt.c | 6 ------ 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index deafa9fe602b..2a08418db3d1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -701,6 +701,7 @@ static void set_load_weight(struct task_struct *p, bool update_load) if (idle_policy(p->policy)) { load->weight = scale_load(WEIGHT_IDLEPRIO); load->inv_weight = WMULT_IDLEPRIO; + p->se.runnable_weight = load->weight; return; } @@ -713,6 +714,7 @@ static void set_load_weight(struct task_struct *p, bool update_load) } else { load->weight = scale_load(sched_prio_to_weight[prio]); load->inv_weight = sched_prio_to_wmult[prio]; + p->se.runnable_weight = load->weight; } } diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index 35475c0c5419..d0016b16d23a 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -269,9 +269,6 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runna int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) { - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - if (___update_load_sum(now, cpu, &se->avg, 0, 0, 0)) { ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); return 1; @@ -282,9 +279,6 @@ int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - if (___update_load_sum(now, cpu, &se->avg, !!se->on_rq, !!se->on_rq, cfs_rq->curr == se)) { -- 2.11.0