Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756833Ab3DOUkW (ORCPT ); Mon, 15 Apr 2013 16:40:22 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:56643 "EHLO mail-pb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361Ab3DOUkU (ORCPT ); Mon, 15 Apr 2013 16:40:20 -0400 Date: Mon, 15 Apr 2013 13:40:16 -0700 From: Tejun Heo To: lizefan@huawei.com Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org, mhocko@suse.cz, kamezawa.hiroyu@jp.fujitsu.com, linux-kernel@vger.kernel.org, glommer@parallels.com, vgoyal@redhat.com Subject: [PATCH v2 4/4] memcg: force use_hierarchy if sane_behavior Message-ID: <20130415204016.GA19531@mtj.dyndns.org> References: <1365808259-31073-1-git-send-email-tj@kernel.org> <1365808259-31073-5-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1365808259-31073-5-git-send-email-tj@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2781 Lines: 84 Turn on use_hierarchy by default if sane_behavior is specified and don't create .use_hierarchy file. It is debatable whether to remove .use_hierarchy file or make it ro as the former could make transition easier in certain cases; however, the behavior changes which will be gated by sane_behavior are intensive including changing basic meaning of certain control knobs in a few controllers and I don't really think keeping this piece would make things easier in any noticeable way, so let's remove it. v2: Explain that mem_cgroup_bind() doesn't have to worry about children as suggested by Michal Hocko. Signed-off-by: Tejun Heo Acked-by: Serge E. Hallyn Acked-by: Li Zefan Acked-by: Michal Hocko Acked-by: KAMEZAWA Hiroyuki --- Applying to cgroup/for-3.10. Thanks! include/linux/cgroup.h | 3 +++ mm/memcontrol.c | 17 +++++++++++++++++ 2 files changed, 20 insertions(+) --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -269,6 +269,9 @@ enum { * * - Remount is disallowed. * + * - memcg: use_hierarchy is on by default and the cgroup file for + * the flag is not created. + * * The followings are planned changes. * * - release_agent will be disallowed once replacement notification --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5814,6 +5814,7 @@ static struct cftype mem_cgroup_files[] }, { .name = "use_hierarchy", + .flags = CFTYPE_INSANE, .write_u64 = mem_cgroup_hierarchy_write, .read_u64 = mem_cgroup_hierarchy_read, }, @@ -6784,6 +6785,21 @@ static void mem_cgroup_move_task(struct } #endif +/* + * Cgroup retains root cgroups across [un]mount cycles making it necessary + * to verify sane_behavior flag on each mount attempt. + */ +static void mem_cgroup_bind(struct cgroup *root) +{ + /* + * use_hierarchy is forced with sane_behavior. cgroup core + * guarantees that @root doesn't have any children, so turning it + * on for the root memcg is enough. + */ + if (cgroup_sane_behavior(root)) + mem_cgroup_from_cont(root)->use_hierarchy = true; +} + struct cgroup_subsys mem_cgroup_subsys = { .name = "memory", .subsys_id = mem_cgroup_subsys_id, @@ -6794,6 +6810,7 @@ struct cgroup_subsys mem_cgroup_subsys = .can_attach = mem_cgroup_can_attach, .cancel_attach = mem_cgroup_cancel_attach, .attach = mem_cgroup_move_task, + .bind = mem_cgroup_bind, .base_cftypes = mem_cgroup_files, .early_init = 0, .use_id = 1, -- 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/