From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751603AbeECJ01 (ORCPT ); Thu, 3 May 2018 05:26:27 -0400 Received: from terminus.zytor.com ([198.137.202.136]:51219 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751050AbeECJ0X (ORCPT ); Thu, 3 May 2018 05:26:23 -0400 Date: Thu, 3 May 2018 02:25:28 -0700 From: tip-bot for Vincent Guittot Message-ID: Cc: mingo@kernel.org, hpa@zytor.com, paulmck@linux.vnet.ibm.com, hkallweit1@gmail.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, geert+renesas@glider.be, vincent.guittot@linaro.org, peterz@infradead.org, torvalds@linux-foundation.org Reply-To: hkallweit1@gmail.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, paulmck@linux.vnet.ibm.com, peterz@infradead.org, torvalds@linux-foundation.org, geert+renesas@glider.be, vincent.guittot@linaro.org In-Reply-To: <20180426103133.GA6953@linaro.org> References: <20180426103133.GA6953@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched/fair: Fix the update of blocked load when newly idle Git-Commit-ID: 457be908c83637ee10bda085a23dc05afa3b14a0 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 457be908c83637ee10bda085a23dc05afa3b14a0 Gitweb: https://git.kernel.org/tip/457be908c83637ee10bda085a23dc05afa3b14a0 Author: Vincent Guittot AuthorDate: Thu, 26 Apr 2018 12:19:32 +0200 Committer: Ingo Molnar CommitDate: Thu, 3 May 2018 07:38:03 +0200 sched/fair: Fix the update of blocked load when newly idle With commit: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") ... we release the rq->lock when updating blocked load of idle CPUs. This opens a time window during which another CPU can add a task to this CPU's cfs_rq. The check for newly added task of idle_balance() is not in the common path. Move the out label to include this check. Reported-by: Heiner Kallweit Tested-by: Geert Uytterhoeven Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") Link: http://lkml.kernel.org/r/20180426103133.GA6953@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 54dc31e7ab9b..e3002e5ada31 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9847,6 +9847,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) if (curr_cost > this_rq->max_idle_balance_cost) this_rq->max_idle_balance_cost = curr_cost; +out: /* * While browsing the domains, we released the rq lock, a task could * have been enqueued in the meantime. Since we're not going idle, @@ -9855,7 +9856,6 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) if (this_rq->cfs.h_nr_running && !pulled_task) pulled_task = 1; -out: /* Move the next balance forward */ if (time_after(this_rq->next_balance, next_balance)) this_rq->next_balance = next_balance;