From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759161Ab2J2NsP (ORCPT ); Mon, 29 Oct 2012 09:48:15 -0400 Received: from mx2.parallels.com ([64.131.90.16]:46098 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759108Ab2J2NsN (ORCPT ); Mon, 29 Oct 2012 09:48:13 -0400 Message-ID: <508E8910.40203@parallels.com> Date: Mon, 29 Oct 2012 17:48:00 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121016 Thunderbird/16.0.1 MIME-Version: 1.0 To: Michal Hocko CC: , , , Andrew Morton , Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh Subject: Re: [PATCH v3 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-3-git-send-email-mhocko@suse.cz> In-Reply-To: <1351251453-6140-3-git-send-email-mhocko@suse.cz> 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 10/26/2012 03:37 PM, Michal Hocko wrote: > The root cgroup cannot be destroyed so we never hit it down the > mem_cgroup_pre_destroy path and mem_cgroup_force_empty_write shouldn't > even try to do anything if called for the root. > > This means that mem_cgroup_move_parent doesn't have to bother with the > root cgroup and it can assume it can always move charges upwards. > > Signed-off-by: Michal Hocko > Reviewed-by: Tejun Heo I think it would be safer to have this folded in the last patch, to avoid a weird intermediate state (specially for force_empty). Being a single statement, it doesn't confuse review so much. However, this is also pretty much just a nitpick, do as you prefer. Reviewed-by: Glauber Costa