From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [PATCH v3 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent Date: Wed, 31 Oct 2012 12:31:41 -0400 Message-ID: <20121031163141.GC2305@cmpxchg.org> References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-3-git-send-email-mhocko@suse.cz> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1351251453-6140-3-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Michal Hocko Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton , Tejun Heo , Li Zefan , KAMEZAWA Hiroyuki , Balbir Singh , Glauber Costa On Fri, Oct 26, 2012 at 01:37:29PM +0200, 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 Acked-by: Johannes Weiner