From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH v2 4/4] memcg: force use_hierarchy if sane_behavior Date: Mon, 15 Apr 2013 13:40:16 -0700 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 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; bh=9ejK1zAHHLcuM94c5uYbI+bVfAKQf9zuvW4dZeGrbAY=; b=MXHrZ12F+BJ4bqY3Dxcj/sVKqi24yHnJdorr7BN7dSj7xzMPIDeaAUws6SPM7yL/V/ qIbx9HJ4Mo9kkfGEGtBTY+czQ3FSa+Hw8fRZ3QasufQTgZdS4hKaLImabUSyd5/9IpsJ OT/8AmXZc0MZDGIUWat9fpA/UhG3TSatEaG0tvQW9DJ4q+z366mbjxw9ZPhfsi+iRcRw sCDJmYSP+vitJ64SELt3Adc8mKNLgesQUJ4UHbdvukKXNnGmlrljtsgYuARq9Ogurjdk JS+5VqBg57bKULxuLJrseHiYI1bS2TJ+LKPeqXt5AOJ2JE3SjQ3ddX6hQ4lNNTIrExJS qbJw== Content-Disposition: inline In-Reply-To: <1365808259-31073-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mhocko-AlSwsSmVLrQ@public.gmane.org, kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org 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,