From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750858Ab2IMELj (ORCPT ); Thu, 13 Sep 2012 00:11:39 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:65333 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712Ab2IMELh (ORCPT ); Thu, 13 Sep 2012 00:11:37 -0400 From: Vincent Guittot To: linux-kernel@vger.kernel.org, linaro-dev@lists.linaro.org Cc: peterz@infradead.org, mingo@redhat.com, Vincent Guittot Subject: [RFC] sched: nohz_idle_balance Date: Thu, 13 Sep 2012 06:11:26 +0200 Message-Id: <1347509486-8688-1-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On tickless system, one CPU runs load balance for all idle CPUs. The cpu_load of this CPU is updated before starting the load balance of each other idle CPUs. We should instead update the cpu_load of the balance_cpu. Signed-off-by: Vincent Guittot --- kernel/sched/fair.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1ca4fe4..9ae3a5b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4794,14 +4794,15 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) if (need_resched()) break; - raw_spin_lock_irq(&this_rq->lock); - update_rq_clock(this_rq); - update_idle_cpu_load(this_rq); - raw_spin_unlock_irq(&this_rq->lock); + rq = cpu_rq(balance_cpu); + + raw_spin_lock_irq(&rq->lock); + update_rq_clock(rq); + update_idle_cpu_load(rq); + raw_spin_unlock_irq(&rq->lock); rebalance_domains(balance_cpu, CPU_IDLE); - rq = cpu_rq(balance_cpu); if (time_after(this_rq->next_balance, rq->next_balance)) this_rq->next_balance = rq->next_balance; } -- 1.7.9.5