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=-14.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 590AAC11F69 for ; Fri, 9 Jul 2021 22:00:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F2DC613FD for ; Fri, 9 Jul 2021 22:00:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231372AbhGIWDH (ORCPT ); Fri, 9 Jul 2021 18:03:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:50348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229948AbhGIWDC (ORCPT ); Fri, 9 Jul 2021 18:03:02 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B309B613CA; Fri, 9 Jul 2021 22:00:18 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94.2) (envelope-from ) id 1m1yXh-000CJr-PW; Fri, 09 Jul 2021 18:00:17 -0400 Message-ID: <20210709220017.632244614@goodmis.org> User-Agent: quilt/0.66 Date: Fri, 09 Jul 2021 17:59:56 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Daniel Wagner , Tom Zanussi , "Srivatsa S. Bhat" , stable@kernel.org, "Peter Zijlstra (Intel)" , Ingo Molnar , Valentin Schneider , Paul Gortmaker Subject: [PATCH RT 3/8] sched: Collate affine_move_task() stoppers References: <20210709215953.122804544@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 5.10.47-rt46-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 58b1a45086b5f80f2b2842aa7ed0da51a64a302b upstream. 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()") Cc: stable@kernel.org Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210224131355.500108964@infradead.org Signed-off-by: Paul Gortmaker Signed-off-by: Steven Rostedt (VMware) --- kernel/sched/core.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d497b13efb53..6880c300c624 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2275,30 +2275,23 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag 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)) { -- 2.30.2