From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754135Ab2FSMWg (ORCPT ); Tue, 19 Jun 2012 08:22:36 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:40433 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753820Ab2FSMWf (ORCPT ); Tue, 19 Jun 2012 08:22:35 -0400 Message-ID: <4FE06EEF.2090709@linux.vnet.ibm.com> Date: Tue, 19 Jun 2012 17:52:07 +0530 From: Prashanth Nageshappa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Peter Zijlstra , mingo@kernel.org, LKML , roland@kernel.org, Srivatsa Vaddagiri , efault@gmx.de, Ingo Molnar Subject: [PATCH] sched: reset loop counters if all tasks are pinned and we need to redo load balance Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12061912-7408-0000-0000-000005FC71C4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While load balancing, if all tasks on the source runqueue are pinned, we retry after excluding the corresponding source cpu. However, loop counters env.loop and env.loop_break are not reset before retrying, which can lead to failure in moving the tasks. In this patch we reset env.loop and env.loop_break to their inital values before we retry. Signed-off-by: Prashanth Nageshappa --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 939fd63..60f8b66 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4520,8 +4520,11 @@ more_balance: /* All tasks on this runqueue were pinned by CPU affinity */ if (unlikely(env.flags & LBF_ALL_PINNED)) { cpumask_clear_cpu(cpu_of(busiest), cpus); - if (!cpumask_empty(cpus)) + if (!cpumask_empty(cpus)) { + env.loop = 0; + env.loop_break = sched_nr_migrate_break; goto redo; + } goto out_balanced; } }