From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753953AbeEaGtz (ORCPT ); Thu, 31 May 2018 02:49:55 -0400 Received: from mx2.suse.de ([195.135.220.15]:50816 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753825AbeEaGty (ORCPT ); Thu, 31 May 2018 02:49:54 -0400 Date: Thu, 31 May 2018 08:49:51 +0200 From: Michal Hocko To: Andrew Morton Cc: ufo19890607 , rientjes@google.com, kirill.shutemov@linux.intel.com, aarcange@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, guro@fb.com, yang.s@alibaba-inc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, yuzhoujian Subject: Re: [PATCH v4] Print the memcg's name when system-wide OOM happened Message-ID: <20180531064951.GG15278@dhcp22.suse.cz> References: <1526870386-2439-1-git-send-email-ufo19890607@gmail.com> <20180530134256.bbf7a8639571a3f8910b6a05@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180530134256.bbf7a8639571a3f8910b6a05@linux-foundation.org> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 30-05-18 13:42:56, Andrew Morton wrote: > On Mon, 21 May 2018 03:39:46 +0100 ufo19890607 wrote: > > > From: yuzhoujian > > > > The dump_header does not print the memcg's name when the system > > oom happened. So users cannot locate the certain container which > > contains the task that has been killed by the oom killer. > > > > System oom report will print the memcg's name after this patch, > > so users can get the memcg's path from the oom report and check > > the certain container more quickly. > > lkp-robot is reporting an oops. > > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -433,6 +433,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) > > if (is_memcg_oom(oc)) > > mem_cgroup_print_oom_info(oc->memcg, p); > > else { > > + mem_cgroup_print_oom_memcg_name(oc->memcg, p); > > show_mem(SHOW_MEM_FILTER_NODES, oc->nodemask); > > if (is_dump_unreclaim_slabs()) > > dump_unreclaimable_slab(); > > static inline bool is_memcg_oom(struct oom_control *oc) > { > return oc->memcg != NULL; > } > > So in the mem_cgroup_print_oom_memcg_name() call which this patch adds, > oc->memcg is known to be NULL. How can this possibly work? This version is broken. The current version [1] seems to be doing the right thing in that regards AFAICS. It has some other issues though. Can we drop the current code from the mmotm tree and start over? [1] http://lkml.kernel.org/r/1527413551-5982-1-git-send-email-ufo19890607@gmail.com -- Michal Hocko SUSE Labs