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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 CB908C433E2 for ; Fri, 28 Aug 2020 02:53:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A43792080C for ; Fri, 28 Aug 2020 02:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728215AbgH1Cxw (ORCPT ); Thu, 27 Aug 2020 22:53:52 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:47738 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726854AbgH1Cxv (ORCPT ); Thu, 27 Aug 2020 22:53:51 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07484;MF=xlpang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0U73igQg_1598583227; Received: from xunleideMacBook-Pro.local(mailfrom:xlpang@linux.alibaba.com fp:SMTPD_---0U73igQg_1598583227) by smtp.aliyun-inc.com(127.0.0.1); Fri, 28 Aug 2020 10:53:48 +0800 Subject: Re: [PATCH] sched/fair: Fix wrong cpu selecting from isolated domain From: Xunlei Pang To: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Juri Lelli , Wetp Zhang Cc: linux-kernel@vger.kernel.org References: <1598272219-43040-1-git-send-email-xlpang@linux.alibaba.com> Message-ID: <9bfaa095-2074-e0bb-da0b-81e00c7ca490@linux.alibaba.com> Date: Fri, 28 Aug 2020 10:53:49 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1598272219-43040-1-git-send-email-xlpang@linux.alibaba.com> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/24 PM8:30, Xunlei Pang wrote: > We've met problems that occasionally tasks with full cpumask > (e.g. by putting it into a cpuset or setting to full affinity) > were migrated to our isolated cpus in production environment. > > After some analysis, we found that it is due to the current > select_idle_smt() not considering the sched_domain mask. > > Fix it by checking the valid domain mask in select_idle_smt(). > > Fixes: 10e2f1acd010 ("sched/core: Rewrite and improve select_idle_siblings()) > Reported-by: Wetp Zhang > Signed-off-by: Xunlei Pang > --- > kernel/sched/fair.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 1a68a05..fa942c4 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6075,7 +6075,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int > /* > * Scan the local SMT mask for idle CPUs. > */ > -static int select_idle_smt(struct task_struct *p, int target) > +static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target) > { > int cpu; > > @@ -6083,7 +6083,8 @@ static int select_idle_smt(struct task_struct *p, int target) > return -1; > > for_each_cpu(cpu, cpu_smt_mask(target)) { > - if (!cpumask_test_cpu(cpu, p->cpus_ptr)) > + if (!cpumask_test_cpu(cpu, p->cpus_ptr) || > + !cpumask_test_cpu(cpu, sched_domain_span(sd))) > continue; > if (available_idle_cpu(cpu) || sched_idle_cpu(cpu)) > return cpu; > @@ -6099,7 +6100,7 @@ static inline int select_idle_core(struct task_struct *p, struct sched_domain *s > return -1; > } > > -static inline int select_idle_smt(struct task_struct *p, int target) > +static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target) > { > return -1; > } > @@ -6274,7 +6275,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) > if ((unsigned)i < nr_cpumask_bits) > return i; > > - i = select_idle_smt(p, target); > + i = select_idle_smt(p, sd, target); > if ((unsigned)i < nr_cpumask_bits) > return i; > > Hi Peter, any other comments?