From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx136.postini.com [74.125.245.136]) by kanga.kvack.org (Postfix) with SMTP id B66F76B0032 for ; Tue, 9 Jul 2013 09:10:31 -0400 (EDT) Date: Tue, 9 Jul 2013 15:10:29 +0200 From: Michal Hocko Subject: Re: [PATCH for 3.2] memcg: do not trap chargers with full callstack on OOM Message-ID: <20130709131029.GH20281@dhcp22.suse.cz> References: <20130607131157.GF8117@dhcp22.suse.cz> <20130617122134.2E072BA8@pobox.sk> <20130619132614.GC16457@dhcp22.suse.cz> <20130622220958.D10567A4@pobox.sk> <20130624201345.GA21822@cmpxchg.org> <20130628120613.6D6CAD21@pobox.sk> <20130705181728.GQ17812@cmpxchg.org> <20130705210246.11D2135A@pobox.sk> <20130705191854.GR17812@cmpxchg.org> <20130708014224.50F06960@pobox.sk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130708014224.50F06960@pobox.sk> Sender: owner-linux-mm@kvack.org List-ID: To: azurIt Cc: Johannes Weiner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups mailinglist , KAMEZAWA Hiroyuki On Mon 08-07-13 01:42:24, azurIt wrote: > > CC: "Michal Hocko" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "cgroups mailinglist" , "KAMEZAWA Hiroyuki" > >On Fri, Jul 05, 2013 at 09:02:46PM +0200, azurIt wrote: > >> >I looked at your debug messages but could not find anything that would > >> >hint at a deadlock. All tasks are stuck in the refrigerator, so I > >> >assume you use the freezer cgroup and enabled it somehow? > >> > >> > >> Yes, i'm really using freezer cgroup BUT i was checking if it's not > >> doing problems - unfortunately, several days passed from that day > >> and now i don't fully remember if i was checking it for both cases > >> (unremoveabled cgroups and these freezed processes holding web > >> server port). I'm 100% sure i was checking it for unremoveable > >> cgroups but not so sure for the other problem (i had to act quickly > >> in that case). Are you sure (from stacks) that freezer cgroup was > >> enabled there? > > > >Yeah, all the traces without exception look like this: > > > >1372089762/23433/stack:[] refrigerator+0x95/0x160 > >1372089762/23433/stack:[] get_signal_to_deliver+0x1cb/0x540 > >1372089762/23433/stack:[] do_signal+0x6b/0x750 > >1372089762/23433/stack:[] do_notify_resume+0x55/0x80 > >1372089762/23433/stack:[] int_signal+0x12/0x17 > >1372089762/23433/stack:[] 0xffffffffffffffff > > > >so the freezer was already enabled when you took the backtraces. > > > >> Btw, what about that other stacks? I mean this file: > >> http://watchdog.sk/lkml/memcg-bug-7.tar.gz > >> > >> It was taken while running the kernel with your patch and from > >> cgroup which was under unresolveable OOM (just like my very original > >> problem). > > > >I looked at these traces too, but none of the tasks are stuck in rmdir > >or the OOM path. Some /are/ in the page fault path, but they are > >happily doing reclaim and don't appear to be stuck. So I'm having a > >hard time matching this data to what you otherwise observed. Agreed. > >However, based on what you reported the most likely explanation for > >the continued hangs is the unfinished OOM handling for which I sent > >the followup patch for arch/x86/mm/fault.c. > > Johannes, > > today I tested both of your patches but problem with unremovable > cgroups, unfortunately, persists. Is the group empty again with marked under_oom? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org