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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 64197C43381 for ; Wed, 24 Feb 2021 14:32:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3654E64EDD for ; Wed, 24 Feb 2021 14:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236001AbhBXOaF (ORCPT ); Wed, 24 Feb 2021 09:30:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234454AbhBXNS1 (ORCPT ); Wed, 24 Feb 2021 08:18:27 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87CF6C061793 for ; Wed, 24 Feb 2021 05:16:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=68OvZzTYc3WqHusX9KvRarCqQE0VdBLlfaAl85h45Yk=; b=e+8TBO9w57nIK7jt0NyAQz7Dsc RVibS41R8MQspAvI4MsKFFgTCuj65d/PACh+qZrs2gyx2k7vtngcFNgnDjiwvHr0Hy0N2Pwm4L+Ym MK+tXTV6cgt6kfQZQxI/cXeOiOZ+r3U18frwa7QX/NIrn8BEajjK+N8UrajoVh91ihY3+9HUS0D6E lvs4yyNlzC4RBAWNIEIHkrCIScE+sojSO0NHaeYuqvgz9NLcCrsFzLIsCSDfWuKrbmRqvTljx8i0j LHRh5t/AZk5CZI2BGB8mi9HS03o2iopSnUaiyl9x7/DPeuwPdPpi6VlIHeguLKZqbXQfJpwW2ii/a +9tuqToA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lEu14-009Qty-Qh; Wed, 24 Feb 2021 13:15:52 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 21A3B30504E; Wed, 24 Feb 2021 14:15:42 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id D8861207C3A73; Wed, 24 Feb 2021 14:15:42 +0100 (CET) Message-ID: <20210224131355.500108964@infradead.org> User-Agent: quilt/0.66 Date: Wed, 24 Feb 2021 13:24:42 +0100 From: Peter Zijlstra To: Ingo Molnar , Thomas Gleixner Cc: Valentin Schneider , Vincent Guittot , Mel Gorman , Dietmar Eggemann , linux-kernel@vger.kernel.org, peterz@infradead.org, Andi Kleen Subject: [PATCH 3/6] sched: Collate affine_move_task() stoppers References: <20210224122439.176543586@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The SCA_MIGRATE_ENABLE and task_running() cases are almost identical, collapse them to avoid further duplication. Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()") Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2239,30 +2239,23 @@ static int affine_move_task(struct rq *r return -EINVAL; } - if (flags & SCA_MIGRATE_ENABLE) { - - refcount_inc(&pending->refs); /* pending->{arg,stop_work} */ - p->migration_flags &= ~MDF_PUSH; - task_rq_unlock(rq, p, rf); - - stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop, - &pending->arg, &pending->stop_work); - - return 0; - } - if (task_running(rq, p) || p->state == TASK_WAKING) { /* - * Lessen races (and headaches) by delegating - * is_migration_disabled(p) checks to the stopper, which will - * run on the same CPU as said p. + * MIGRATE_ENABLE gets here because 'p == current', but for + * anything else we cannot do is_migration_disabled(), punt + * and have the stopper function handle it all race-free. */ + refcount_inc(&pending->refs); /* pending->{arg,stop_work} */ + if (flags & SCA_MIGRATE_ENABLE) + p->migration_flags &= ~MDF_PUSH; task_rq_unlock(rq, p, rf); stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop, &pending->arg, &pending->stop_work); + if (flags & SCA_MIGRATE_ENABLE) + return 0; } else { if (!is_migration_disabled(p)) {