From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752089Ab2GZJLt (ORCPT ); Thu, 26 Jul 2012 05:11:49 -0400 Received: from mga14.intel.com ([143.182.124.37]:21010 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751364Ab2GZJLq (ORCPT ); Thu, 26 Jul 2012 05:11:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="173395181" Message-ID: <501109DD.7020501@intel.com> Date: Thu, 26 Jul 2012 17:11:57 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111229 Thunderbird/9.0 MIME-Version: 1.0 To: Peter Zijlstra CC: mingo@redhat.com, linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com Subject: Re: [PATCH 2/2] sched: fix a logical error in select_task_rq_fair References: <1343280446-24019-1-git-send-email-alex.shi@intel.com> <1343280446-24019-2-git-send-email-alex.shi@intel.com> <1343290631.26034.86.camel@twins> In-Reply-To: <1343290631.26034.86.camel@twins> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2012 04:17 PM, Peter Zijlstra wrote: > On Thu, 2012-07-26 at 13:27 +0800, Alex Shi wrote: >> If find_idlest_cpu() return '-1', and sd->child is NULL. The function >> select_task_rq_fair will return -1. That is not the function's purpose. > > But find_idlest_cpu() will only return -1 if the group mask is fully > excluded by the cpus_allowed mask, right? Yes. > > In that case aren't we covering up a bug in find_idlest_group(), it > appears to have returned a group that isn't eligible to be idlest. If it is possible happening in sched_domain rebuilding? I didn't meet this bug. Just guess. > >