From: Michal Hocko <mhocko@suse.cz>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
rientjes@google.com, oleg@redhat.com
Subject: Re: [RFC PATCH] oom: Don't count on mm-less current process.
Date: Tue, 23 Dec 2014 14:09:09 +0100 [thread overview]
Message-ID: <20141223130909.GE28549@dhcp22.suse.cz> (raw)
In-Reply-To: <201412232200.BCI48944.LJFSFVOFHMOtQO@I-love.SAKURA.ne.jp>
On Tue 23-12-14 22:00:52, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > > and finally sets SIGKILL on that victim thread. If such a delay
> > > happened, that victim thread is free to abuse TIF_MEMDIE for that period.
> > > Thus, I thought sending SIGKILL followed by setting TIF_MEMDIE is better.
> >
> > I don't know, I can hardly find a scenario where it would make any
> > difference in the real life. If the victim needs to allocate a memory to
> > finish then it would trigger OOM again and have to wait/loop until this
> > OOM killer releases the oom zonelist lock just to find out it already
> > has TIF_MEMDIE set and can dive into memory reserves. Which way is more
> > correct is a question but I wouldn't change it without having a really
> > good reason. This whole code is subtle already, let's not make it even
> > more so.
>
> gfp_to_alloc_flags() in mm/page_alloc.c sets ALLOC_NO_WATERMARKS if
> the victim task has TIF_MEMDIE flag, doesn't it?
This is the whole point of TIF_MEMDIE.
[...]
> Then, I think deferring SIGKILL might widen race window for abusing TIF_MEMDIE.
How would it abuse the flag? The OOM victim has to die and if it needs
to allocate then we have to allow it to do so otherwise the whole
exercise was pointless. fatal_signal_pending check is not so widespread
in the kernel that the task would notice it immediately.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2014-12-23 13:09 UTC|newest]
Thread overview: 177+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-12 13:54 Tetsuo Handa
2014-12-16 12:47 ` Michal Hocko
2014-12-17 11:54 ` Tetsuo Handa
2014-12-17 13:08 ` Michal Hocko
2014-12-18 12:11 ` Tetsuo Handa
2014-12-18 15:33 ` Michal Hocko
2014-12-19 12:07 ` Tetsuo Handa
2014-12-19 12:49 ` Michal Hocko
2014-12-20 9:13 ` Tetsuo Handa
2014-12-20 11:42 ` Tetsuo Handa
2014-12-22 20:25 ` Michal Hocko
2014-12-23 1:00 ` Tetsuo Handa
2014-12-23 9:51 ` Michal Hocko
2014-12-23 11:46 ` Tetsuo Handa
2014-12-23 11:57 ` Tetsuo Handa
2014-12-23 12:12 ` Tetsuo Handa
2014-12-23 12:27 ` Michal Hocko
2014-12-23 12:24 ` Michal Hocko
2014-12-23 13:00 ` Tetsuo Handa
2014-12-23 13:09 ` Michal Hocko [this message]
2014-12-23 13:20 ` Tetsuo Handa
2014-12-23 13:43 ` Michal Hocko
2014-12-23 14:11 ` Tetsuo Handa
2014-12-23 14:57 ` Michal Hocko
2014-12-19 12:22 ` How to handle TIF_MEMDIE stalls? Tetsuo Handa
2014-12-20 2:03 ` Dave Chinner
2014-12-20 12:41 ` Tetsuo Handa
2014-12-20 22:35 ` Dave Chinner
2014-12-21 8:45 ` Tetsuo Handa
2014-12-21 20:42 ` Dave Chinner
2014-12-22 16:57 ` Michal Hocko
2014-12-22 21:30 ` Dave Chinner
2014-12-23 9:41 ` Johannes Weiner
2014-12-24 1:06 ` Dave Chinner
2014-12-24 2:40 ` Linus Torvalds
2014-12-29 18:19 ` Michal Hocko
2014-12-30 6:42 ` Tetsuo Handa
2014-12-30 11:21 ` Michal Hocko
2014-12-30 13:33 ` Tetsuo Handa
2014-12-31 10:24 ` Tetsuo Handa
2015-02-09 11:44 ` Tetsuo Handa
2015-02-10 13:58 ` Tetsuo Handa
2015-02-10 15:19 ` Johannes Weiner
2015-02-11 2:23 ` Tetsuo Handa
2015-02-11 13:37 ` Tetsuo Handa
2015-02-11 18:50 ` Oleg Nesterov
2015-02-11 18:59 ` Oleg Nesterov
2015-03-14 13:03 ` Tetsuo Handa
2015-02-17 12:23 ` Tetsuo Handa
2015-02-17 12:53 ` Johannes Weiner
2015-02-17 15:38 ` Michal Hocko
2015-02-17 22:54 ` Dave Chinner
2015-02-17 23:32 ` Dave Chinner
2015-02-18 8:25 ` Michal Hocko
2015-02-18 10:48 ` Dave Chinner
2015-02-18 12:16 ` Michal Hocko
2015-02-18 21:31 ` Dave Chinner
2015-02-19 9:40 ` Michal Hocko
2015-02-19 22:03 ` Dave Chinner
2015-02-20 9:27 ` Michal Hocko
2015-02-19 11:01 ` Johannes Weiner
2015-02-19 12:29 ` Michal Hocko
2015-02-19 12:58 ` Michal Hocko
2015-02-19 15:29 ` Tetsuo Handa
2015-02-19 21:53 ` Tetsuo Handa
2015-02-20 9:13 ` Michal Hocko
2015-02-20 13:37 ` Stefan Ring
2015-02-19 13:29 ` Tetsuo Handa
2015-02-20 9:10 ` Michal Hocko
2015-02-20 12:20 ` Tetsuo Handa
2015-02-20 12:38 ` Michal Hocko
2015-02-19 21:43 ` Dave Chinner
2015-02-20 12:48 ` Michal Hocko
2015-02-20 23:09 ` Dave Chinner
2015-02-19 10:24 ` Johannes Weiner
2015-02-19 22:52 ` Dave Chinner
2015-02-20 10:36 ` Tetsuo Handa
2015-02-20 23:15 ` Dave Chinner
2015-02-21 3:20 ` Theodore Ts'o
2015-02-21 9:19 ` Andrew Morton
2015-02-21 13:48 ` Tetsuo Handa
2015-02-21 21:38 ` Dave Chinner
2015-02-22 0:20 ` Johannes Weiner
2015-02-23 10:48 ` Michal Hocko
2015-02-23 11:23 ` Tetsuo Handa
2015-02-23 21:33 ` David Rientjes
2015-02-22 14:48 ` __GFP_NOFAIL and oom_killer_disabled? Tetsuo Handa
2015-02-23 10:21 ` Michal Hocko
2015-02-23 13:03 ` Tetsuo Handa
2015-02-24 18:14 ` Michal Hocko
2015-02-25 11:22 ` Tetsuo Handa
2015-02-25 16:02 ` Michal Hocko
2015-02-25 21:48 ` Tetsuo Handa
2015-02-25 21:51 ` Andrew Morton
2015-02-21 12:00 ` How to handle TIF_MEMDIE stalls? Tetsuo Handa
2015-02-23 10:26 ` Michal Hocko
2015-02-21 11:12 ` Tetsuo Handa
2015-02-21 21:48 ` Dave Chinner
2015-02-21 23:52 ` Johannes Weiner
2015-02-23 0:45 ` Dave Chinner
2015-02-23 1:29 ` Andrew Morton
2015-02-23 7:32 ` Dave Chinner
2015-02-27 18:24 ` Vlastimil Babka
2015-02-28 0:03 ` Dave Chinner
2015-02-28 15:17 ` Theodore Ts'o
2015-03-02 9:39 ` Vlastimil Babka
2015-03-02 22:31 ` Dave Chinner
2015-03-03 9:13 ` Vlastimil Babka
2015-03-04 1:33 ` Dave Chinner
2015-03-04 8:50 ` Vlastimil Babka
2015-03-04 11:03 ` Dave Chinner
2015-03-07 0:20 ` Johannes Weiner
2015-03-07 3:43 ` Dave Chinner
2015-03-07 15:08 ` Johannes Weiner
2015-03-02 20:22 ` Johannes Weiner
2015-03-02 23:12 ` Dave Chinner
2015-03-03 2:50 ` Johannes Weiner
2015-03-04 6:52 ` Dave Chinner
2015-03-04 15:04 ` Johannes Weiner
2015-03-04 17:38 ` Theodore Ts'o
2015-03-04 23:17 ` Dave Chinner
2015-02-28 16:29 ` Johannes Weiner
2015-02-28 16:41 ` Theodore Ts'o
2015-02-28 22:15 ` Johannes Weiner
2015-03-01 11:17 ` Tetsuo Handa
2015-03-06 11:53 ` Tetsuo Handa
2015-03-01 13:43 ` Theodore Ts'o
2015-03-01 16:15 ` Johannes Weiner
2015-03-01 19:36 ` Theodore Ts'o
2015-03-01 20:44 ` Johannes Weiner
2015-03-01 20:17 ` Johannes Weiner
2015-03-01 21:48 ` Dave Chinner
2015-03-02 0:17 ` Dave Chinner
2015-03-02 12:46 ` Brian Foster
2015-02-28 18:36 ` Vlastimil Babka
2015-03-02 15:18 ` Michal Hocko
2015-03-02 16:05 ` Johannes Weiner
2015-03-02 17:10 ` Michal Hocko
2015-03-02 17:27 ` Johannes Weiner
2015-03-02 16:39 ` Theodore Ts'o
2015-03-02 16:58 ` Michal Hocko
2015-03-04 12:52 ` Dave Chinner
2015-02-17 14:59 ` Michal Hocko
2015-02-17 14:50 ` Michal Hocko
2015-02-17 14:37 ` Michal Hocko
2015-02-17 14:44 ` Michal Hocko
2015-02-16 11:23 ` Tetsuo Handa
2015-02-16 15:42 ` Johannes Weiner
2015-02-17 11:57 ` Tetsuo Handa
2015-02-17 13:16 ` Johannes Weiner
2015-02-17 16:50 ` Michal Hocko
2015-02-17 23:25 ` Dave Chinner
2015-02-18 8:48 ` Michal Hocko
2015-02-18 11:23 ` Tetsuo Handa
2015-02-18 12:29 ` Michal Hocko
2015-02-18 14:06 ` Tetsuo Handa
2015-02-18 14:25 ` Michal Hocko
2015-02-19 10:48 ` Tetsuo Handa
2015-02-20 8:26 ` Michal Hocko
2015-02-23 22:08 ` David Rientjes
2015-02-24 11:20 ` Tetsuo Handa
2015-02-24 15:20 ` Theodore Ts'o
2015-02-24 21:02 ` Dave Chinner
2015-02-25 14:31 ` Tetsuo Handa
2015-02-27 7:39 ` Dave Chinner
2015-02-27 12:42 ` Tetsuo Handa
2015-02-27 13:12 ` Dave Chinner
2015-03-04 12:41 ` Tetsuo Handa
2015-03-04 13:25 ` Dave Chinner
2015-03-04 14:11 ` Tetsuo Handa
2015-03-05 1:36 ` Dave Chinner
2015-02-17 16:33 ` Michal Hocko
2014-12-29 17:40 ` [PATCH] mm: get rid of radix tree gfp mask for pagecache_get_page (was: Re: How to handle TIF_MEMDIE stalls?) Michal Hocko
2014-12-29 18:45 ` Linus Torvalds
2014-12-29 19:33 ` Michal Hocko
2014-12-30 13:42 ` Michal Hocko
2014-12-30 21:45 ` Linus Torvalds
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