Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754109AbZDPB1S (ORCPT ); Wed, 15 Apr 2009 21:27:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751294AbZDPB1F (ORCPT ); Wed, 15 Apr 2009 21:27:05 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:55639 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751029AbZDPB1E (ORCPT ); Wed, 15 Apr 2009 21:27:04 -0400 Message-ID: <49E6887D.6030400@cn.fujitsu.com> Date: Thu, 16 Apr 2009 09:23:09 +0800 From: Miao Xie Reply-To: miaox@cn.fujitsu.com User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , Linux-Kernel Subject: Re: [PATCH] sched: fix off-by-one bug in balance_tasks() References: <49E54B2A.9060100@cn.fujitsu.com> <1239795719.22720.2231.camel@laptop> In-Reply-To: <1239795719.22720.2231.camel@laptop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1353 Lines: 43 on 2009-4-15 19:41 Peter Zijlstra wrote: > On Wed, 2009-04-15 at 10:49 +0800, Miao Xie wrote: >> If the load that need be moved equals the half weight of a task, I think >> it is unnecessary to move this task. Or this task will be moved back and >> forth. > > That's actually desirable. Consider the 3 tasks on 2 cpus statically > infeasible scenario. There you'd want the tasks to bounce around a bit > in order to provide fairness. I see. Thanks for your explanation. Miao Xie > >> Signed-off-by: Miao Xie >> --- >> kernel/sched.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/sched.c b/kernel/sched.c >> index 5724508..44926c8 100644 >> --- a/kernel/sched.c >> +++ b/kernel/sched.c >> @@ -3085,7 +3085,7 @@ next: >> if (!p || loops++ > sysctl_sched_nr_migrate) >> goto out; >> >> - if ((p->se.load.weight >> 1) > rem_load_move || >> + if ((p->se.load.weight >> 1) >= rem_load_move || >> !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { >> p = iterator->next(iterator->arg); >> goto next; > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/