From mboxrd@z Thu Jan 1 00:00:00 1970 From: Serge Hallyn Subject: Re: Protection against container fork bombs [WAS: Re: memcg with kmem limit doesn't recover after disk i/o causes limit to be hit] Date: Tue, 29 Apr 2014 13:03:53 +0000 Message-ID: <20140429130353.GA27354@ubuntumail> References: <20140416154650.GA3034@alpha.arachsys.com> <20140418155939.GE4523@dhcp22.suse.cz> <5351679F.5040908@parallels.com> <20140420142830.GC22077@alpha.arachsys.com> <20140422143943.20609800@oracle.com> <20140422200531.GA19334@alpha.arachsys.com> <535758A0.5000500@yuhu.biz> <20140423084942.560ae837@oracle.com> <20140428180025.GC25689@ubuntumail> <20140429072515.GB15058@dhcp22.suse.cz> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20140429072515.GB15058-2MMpYkNvuYDjFM9bn6wA6Q@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: Richard Davies , Vladimir Davydov , Marian Marinov , Max Kellermann , Tim Hockin , Frederic Weisbecker , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Daniel Walsh , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Glauber Costa , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, William Dauchy , Johannes Weiner , Tejun Heo , David Rientjes Quoting Michal Hocko (mhocko-AlSwsSmVLrQ@public.gmane.org): > On Mon 28-04-14 18:00:25, Serge Hallyn wrote: > > Quoting Dwight Engen (dwight.engen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org): > > > On Wed, 23 Apr 2014 09:07:28 +0300 > > > Marian Marinov wrote: > > > > > > > On 04/22/2014 11:05 PM, Richard Davies wrote: > > > > > Dwight Engen wrote: > > > > >> Richard Davies wrote: > > > > >>> Vladimir Davydov wrote: > > > > >>>> In short, kmem limiting for memory cgroups is currently broken. > > > > >>>> Do not use it. We are working on making it usable though. > > > > > ... > > > > >>> What is the best mechanism available today, until kmem limits > > > > >>> mature? > > > > >>> > > > > >>> RLIMIT_NPROC exists but is per-user, not per-container. > > > > >>> > > > > >>> Perhaps there is an up-to-date task counter patchset or similar? > > > > >> > > > > >> I updated Frederic's task counter patches and included Max > > > > >> Kellermann's fork limiter here: > > > > >> > > > > >> http://thread.gmane.org/gmane.linux.kernel.containers/27212 > > > > >> > > > > >> I can send you a more recent patchset (against 3.13.10) if you > > > > >> would find it useful. > > > > > > > > > > Yes please, I would be interested in that. Ideally even against > > > > > 3.14.1 if you have that too. > > > > > > > > Dwight, do you have these patches in any public repo? > > > > > > > > I would like to test them also. > > > > > > Hi Marian, I put the patches against 3.13.11 and 3.14.1 up at: > > > > > > git://github.com/dwengen/linux.git cpuacct-task-limit-3.13 > > > git://github.com/dwengen/linux.git cpuacct-task-limit-3.14 > > > > Thanks, Dwight. FWIW I'm agreed with Tim, Dwight, Richard, and Marian > > that a task limit would be a proper cgroup extension, and specifically > > that approximating that with a kmem limit is not a reasonable substitute. > > The current state of the kmem limit, which is improving a lot thanks to > Vladimir, is not a reason for a new extension/controller. We are just > not yet there. It has nothing to do with the state of the limit. I simply don't believe that emulating RLIMIT_NPROC by controlling stack size is a good idea. -serge