From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752426Ab1LQQlz (ORCPT <rfc822;w@1wt.eu>);
	Sat, 17 Dec 2011 11:41:55 -0500
Received: from mail-ww0-f44.google.com ([74.125.82.44]:39371 "EHLO
	mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752297Ab1LQQlx (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Sat, 17 Dec 2011 11:41:53 -0500
Date: Sat, 17 Dec 2011 17:41:48 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizf@cn.fujitsu.com>,
        linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org,
        cgroups@vger.kernel.org,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Paul Menage <paul@paulmenage.org>
Subject: Re: [PATCH] cgroup: remove redundate get/put of old css_set from
 migrate
Message-ID: <20111217164145.GA437@somewhere>
References: <1324053511-24591-1-git-send-email-msb@chromium.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1324053511-24591-1-git-send-email-msb@chromium.org>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Dec 16, 2011 at 08:38:31AM -0800, Mandeep Singh Baines wrote:
> We can now assume that the css_set reference held by the task
> will not go away for an exiting task. PF_EXITING state can be
> trusted throughout migration by checking it after locking
> threadgroup.
> 
> This patch depends on:
> 
> commit cd3d095275374220921fcf0d4e0c16584b26ddbc
> Author: Tejun Heo <tj@kernel.org>
> Date:   Mon Dec 12 18:12:21 2011 -0800
> 
>     cgroup: always lock threadgroup during migration
> 
> Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Li Zefan <lizf@cn.fujitsu.com>
> Cc: containers@lists.linux-foundation.org
> Cc: cgroups@vger.kernel.org
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>

> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Paul Menage <paul@paulmenage.org>
> ---
>  kernel/cgroup.c |   25 ++++++-------------------
>  1 files changed, 6 insertions(+), 19 deletions(-)