From: Michal Hocko <mhocko@suse.cz>
To: Tejun Heo <tj@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, linux-pm@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
"\\\"Rafael J. Wysocki\\\"" <rjw@rjwysocki.net>,
David Rientjes <rientjes@google.com>,
Oleg Nesterov <oleg@redhat.com>,
Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [RFC 0/4] OOM vs PM freezer fixes
Date: Tue, 18 Nov 2014 22:08:33 +0100 [thread overview]
Message-ID: <20141118210833.GE23640@dhcp22.suse.cz> (raw)
In-Reply-To: <20141114201419.GI25889@htj.dyndns.org>
On Fri 14-11-14 15:14:19, Tejun Heo wrote:
> On Wed, Nov 12, 2014 at 07:58:48PM +0100, Michal Hocko wrote:
> > Hi,
> > here is another take at OOM vs. PM freezer interaction fixes/cleanups.
> > First three patches are fixes for an unlikely cases when OOM races with
> > the PM freezer which should be closed completely finally. The last patch
> > is a simple code enhancement which is not needed strictly speaking but
> > it is nice to have IMO.
> >
> > Both OOM killer and PM freezer are quite subtle so I hope I haven't
> > missing anything. Any feedback is highly appreciated. I am also
> > interested about feedback for the used approach. To be honest I am not
> > really happy about spreading TIF_MEMDIE checks into freezer (patch 1)
> > but I didn't find any other way for detecting OOM killed tasks.
>
> I really don't get why this is structured this way. Can't you just do
> the following?
Well, I liked how simple this was and localized at the only place which
matters. When I was thinking about a solution which you are describing
below it was more complicated and more subtle (e.g. waiting for an OOM
victim might be tricky if it stumbles over a lock which is held by a
frozen thread which uses try_to_freeze_unsafe). Anyway I gave it another
try and will post the two patches as a reply to this email. I hope the
both interface and implementation is cleaner.
> 1. Freeze all freezables. Don't worry about PF_MEMDIE.
>
> 2. Disable OOM killer. This should be contained in the OOM killer
> proper. Lock out the OOM killer and disable it.
>
> 3. At this point, we know that no one will create more freezable
> threads and no new process will be OOM kliled. Wait till there's
> no process w/ PF_MEMDIE set.
>
> There's no reason to lock out or disable OOM killer while the system
> is not in the quiescent state, which is a big can of worms. Bring
> down the system to the quiescent state, disable the OOM killer and
> then drain PF_MEMDIEs.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2014-11-18 21:08 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 7:27 [PATCH 0/4 -v2] OOM vs. freezer interaction fixes Michal Hocko
2014-10-21 7:27 ` [PATCH 1/4] freezer: Do not freeze tasks killed by OOM killer Michal Hocko
2014-10-21 12:04 ` Rafael J. Wysocki
2014-10-21 7:27 ` [PATCH 2/4] freezer: remove obsolete comments in __thaw_task() Michal Hocko
2014-10-21 12:04 ` Rafael J. Wysocki
2014-10-21 7:27 ` [PATCH 3/4] OOM, PM: OOM killed task shouldn't escape PM suspend Michal Hocko
2014-10-21 12:09 ` Rafael J. Wysocki
2014-10-21 13:14 ` Michal Hocko
2014-10-21 13:42 ` Rafael J. Wysocki
2014-10-21 14:11 ` Michal Hocko
2014-10-21 14:41 ` Rafael J. Wysocki
2014-10-21 14:29 ` Michal Hocko
2014-10-22 14:39 ` Rafael J. Wysocki
2014-10-22 14:22 ` Michal Hocko
2014-10-22 21:18 ` Rafael J. Wysocki
2014-10-26 18:49 ` Pavel Machek
2014-11-04 19:27 ` Tejun Heo
2014-11-05 12:46 ` Michal Hocko
2014-11-05 13:02 ` Tejun Heo
2014-11-05 13:31 ` Michal Hocko
2014-11-05 13:42 ` Michal Hocko
2014-11-05 14:14 ` Michal Hocko
2014-11-05 15:45 ` Michal Hocko
2014-11-05 15:44 ` Tejun Heo
2014-11-05 16:01 ` Michal Hocko
2014-11-05 16:29 ` Tejun Heo
2014-11-05 16:39 ` Michal Hocko
2014-11-05 16:54 ` Tejun Heo
2014-11-05 17:01 ` Tejun Heo
2014-11-06 13:05 ` Michal Hocko
2014-11-06 15:09 ` Tejun Heo
2014-11-06 16:01 ` Michal Hocko
2014-11-06 16:12 ` Tejun Heo
2014-11-06 16:31 ` Michal Hocko
2014-11-06 16:33 ` Tejun Heo
2014-11-06 16:58 ` Michal Hocko
2014-11-05 17:46 ` Michal Hocko
2014-11-05 17:55 ` Tejun Heo
2014-11-06 12:49 ` Michal Hocko
2014-11-06 15:01 ` Tejun Heo
2014-11-06 16:02 ` Michal Hocko
2014-11-06 16:28 ` Tejun Heo
2014-11-10 16:30 ` Michal Hocko
2014-11-12 18:58 ` [RFC 0/4] OOM vs PM freezer fixes Michal Hocko
2014-11-12 18:58 ` [RFC 1/4] OOM, PM: Do not miss OOM killed frozen tasks Michal Hocko
2014-11-14 17:55 ` Tejun Heo
2014-11-12 18:58 ` [RFC 2/4] OOM, PM: make OOM detection in the freezer path raceless Michal Hocko
2014-11-12 18:58 ` [RFC 3/4] OOM, PM: handle pm freezer as an OOM victim correctly Michal Hocko
2014-11-12 18:58 ` [RFC 4/4] OOM: thaw the OOM victim if it is frozen Michal Hocko
2014-11-14 20:14 ` [RFC 0/4] OOM vs PM freezer fixes Tejun Heo
2014-11-18 21:08 ` Michal Hocko [this message]
2014-11-18 21:10 ` [RFC 1/2] oom: add helper for setting and clearing TIF_MEMDIE Michal Hocko
2014-11-18 21:10 ` [RFC 2/2] OOM, PM: make OOM detection in the freezer path raceless Michal Hocko
2014-11-27 0:47 ` Rafael J. Wysocki
2014-12-02 22:08 ` Tejun Heo
2014-12-04 14:16 ` Michal Hocko
2014-12-04 14:44 ` Tejun Heo
2014-12-04 16:56 ` Michal Hocko
2014-12-04 17:18 ` Michal Hocko
2014-12-05 16:41 ` [PATCH 0/4] OOM vs PM freezer fixes Michal Hocko
2014-12-05 16:41 ` [PATCH -v2 1/5] oom: add helpers for setting and clearing TIF_MEMDIE Michal Hocko
2014-12-06 12:56 ` Tejun Heo
2014-12-07 10:13 ` Michal Hocko
2015-01-07 17:57 ` Tejun Heo
2015-01-07 18:23 ` Michal Hocko
2014-12-05 16:41 ` [PATCH -v2 2/5] OOM: thaw the OOM victim if it is frozen Michal Hocko
2014-12-06 13:06 ` Tejun Heo
2014-12-07 10:24 ` Michal Hocko
2014-12-07 10:45 ` Michal Hocko
2014-12-07 13:59 ` Tejun Heo
2014-12-07 18:55 ` Michal Hocko
2014-12-05 16:41 ` [PATCH -v2 3/5] PM: convert printk to pr_* equivalent Michal Hocko
2014-12-05 22:40 ` Rafael J. Wysocki
2014-12-07 10:26 ` Michal Hocko
2014-12-06 13:08 ` Tejun Heo
2014-12-05 16:41 ` [PATCH -v2 4/5] sysrq: " Michal Hocko
2014-12-06 13:09 ` Tejun Heo
2014-12-05 16:41 ` [PATCH -v2 5/5] OOM, PM: make OOM detection in the freezer path raceless Michal Hocko
2014-12-06 13:11 ` Tejun Heo
2014-12-07 10:11 ` Michal Hocko
2015-01-07 18:41 ` Tejun Heo
2015-01-07 18:48 ` Michal Hocko
2015-01-08 11:51 ` Michal Hocko
2014-12-07 10:09 ` [PATCH 0/4] OOM vs PM freezer fixes Michal Hocko
2014-12-07 13:55 ` Tejun Heo
2014-12-07 19:00 ` Michal Hocko
2014-12-18 16:27 ` Michal Hocko
2014-11-05 14:55 ` [PATCH 3/4] OOM, PM: OOM killed task shouldn't escape PM suspend Michal Hocko
2014-10-26 18:40 ` Pavel Machek
2014-10-21 7:27 ` [PATCH 4/4] PM: convert do_each_thread to for_each_process_thread Michal Hocko
2014-10-21 12:10 ` Rafael J. Wysocki
2014-10-21 13:19 ` Michal Hocko
2014-10-21 13:43 ` Rafael J. Wysocki
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