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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,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 82A5DC43331 for ; Mon, 11 Nov 2019 09:32:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EC232075B for ; Mon, 11 Nov 2019 09:32:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727223AbfKKJc5 (ORCPT ); Mon, 11 Nov 2019 04:32:57 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:55815 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726845AbfKKJc4 (ORCPT ); Mon, 11 Nov 2019 04:32:56 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iU63q-00039c-2k; Mon, 11 Nov 2019 10:32:38 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 843B01C03AB; Mon, 11 Nov 2019 10:32:36 +0100 (CET) Date: Mon, 11 Nov 2019 09:32:36 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Better document newidle_balance() Cc: "Peter Zijlstra (Intel)" , Linus Torvalds , Thomas Gleixner , bsegall@google.com, dietmar.eggemann@arm.com, juri.lelli@redhat.com, ktkhai@virtuozzo.com, mgorman@suse.de, qais.yousef@arm.com, qperret@google.com, rostedt@goodmis.org, valentin.schneider@arm.com, vincent.guittot@linaro.org, Ingo Molnar , Borislav Petkov , linux-kernel@vger.kernel.org In-Reply-To: <20191108131909.488364308@infradead.org> References: <20191108131909.488364308@infradead.org> MIME-Version: 1.0 Message-ID: <157346475624.29376.10025173920245642380.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 7277a34c6be0b2972bdd1fea88c7cef409bed5b4 Gitweb: https://git.kernel.org/tip/7277a34c6be0b2972bdd1fea88c7cef409bed5b4 Author: Peter Zijlstra AuthorDate: Fri, 08 Nov 2019 14:15:55 +01:00 Committer: Ingo Molnar CommitterDate: Mon, 11 Nov 2019 08:35:18 +01:00 sched/fair: Better document newidle_balance() Whilst chasing the pick_next_task() race, there was some confusion about the newidle_balance() return values. Document them. [ mingo: Minor edits. ] Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: juri.lelli@redhat.com Cc: ktkhai@virtuozzo.com Cc: mgorman@suse.de Cc: qais.yousef@arm.com Cc: qperret@google.com Cc: rostedt@goodmis.org Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: https://lkml.kernel.org/r/20191108131909.488364308@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6e622f4..c48a695 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9941,6 +9941,11 @@ static inline void nohz_newidle_balance(struct rq *this_rq) { } /* * idle_balance is called by schedule() if this_cpu is about to become * idle. Attempts to pull tasks from other CPUs. + * + * Returns: + * < 0 - we released the lock and there are !fair tasks present + * 0 - failed, no new tasks + * > 0 - success, new (fair) tasks present */ int newidle_balance(struct rq *this_rq, struct rq_flags *rf) {