From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: memcg creates an unkillable task in 3.2-rc2 Date: Tue, 30 Jul 2013 09:58:58 +0800 Message-ID: <51F71DE2.4020102@huawei.com> References: <20130723174711.GE21100@mtj.dyndns.org> <8761vui4cr.fsf@xmission.com> <20130729075939.GA4678@dhcp22.suse.cz> <87ehahg312.fsf@xmission.com> <20130729095109.GB4678@dhcp22.suse.cz> <20130729161026.GD22605@mtj.dyndns.org> <87r4eh70yg.fsf@xmission.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87r4eh70yg.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "Eric W. Biederman" Cc: Tejun Heo , Michal Hocko , Linus Torvalds , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kent.overstreet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Glauber Costa , Johannes Weiner > I am also seeing what looks like a leak somewhere in the cgroup code as > well. After some runs of the same reproducer I get into a state where > after everything is clean up. All of the control groups have been > removed and the cgroup filesystem is unmounted, I can mount a cgroup > filesystem with that same combindation of subsystems, but I can't mount > a cgroup filesystem with any of those subsystems in any other > combination. So I am guessing that the superblock is from the original > mounting is still lingering for some reason. > If this happens again, you can check /proc/cgroups, #subsys_name hierarchy num_cgroups enabled cpuset 0 1 1 debug 0 1 1 cpu 0 1 1 cpuacct 0 1 1 memory 0 1 1 devices 0 1 1 freezer 0 1 1 blkio 0 1 1 If "hierachy" is not 0, then it didn't really unmounted. If "num_cgroups" is not 1, then there're some cgroups not really destroyed though they've been rmdired.