On Tue 01-08-17 13:42:38, Roman Gushchin wrote: > On Tue, Aug 01, 2017 at 02:29:05PM +0200, Michal Hocko wrote: > > On Tue 01-08-17 13:23:44, Roman Gushchin wrote: > > > On Tue, Aug 01, 2017 at 02:16:44PM +0200, Michal Hocko wrote: > > > > On Thu 27-07-17 11:03:55, Michal Hocko wrote: > > > > > Hi, > > > > > this is a part of a larger series I posted back in Oct last year [1]. I > > > > > have dropped patch 3 because it was incorrect and patch 4 is not > > > > > applicable without it. > > > > > > > > > > The primary reason to apply patch 1 is to remove a risk of the complete > > > > > memory depletion by oom victims. While this is a theoretical risk right > > > > > now there is a demand for memcg aware oom killer which might kill all > > > > > processes inside a memcg which can be a lot of tasks. That would make > > > > > the risk quite real. > > > > > > > > > > This issue is addressed by limiting access to memory reserves. We no > > > > > longer use TIF_MEMDIE to grant the access and use tsk_is_oom_victim > > > > > instead. See Patch 1 for more details. Patch 2 is a trivial follow up > > > > > cleanup. > > > > > > > > Any comments, concerns? Can we merge it? > > > > > > I've rebased the cgroup-aware OOM killer and ran some tests. > > > Everything works well. > > > > Thanks for your testing. Can I assume your Tested-by? > > Sure. Thanks! > I wonder if we can get rid of TIF_MEMDIE completely, > if we will count OOM victims on per-oom-victim-signal-struct rather than > on per-thread basis? Say, assign oom_mm using cmpxchg, and call > exit_oom_victim() from __exit_signal()? __thaw_task() can be called from > mark_oom_victim() unconditionally. > > Do you see any problems with this approach? Ohh, I wish we could do that. All my previous attempts failed though. I have always hit the problem to tell that the last thread of the process is exiting to know when to call exit_oom_victim and release the oom disable barrier. Maybe things have changed somehow since I've tried the last time but this is a tricky code. I will certainly get back to it some day but not likely anytime soon. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
