From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH 4/4] mm, oom: Fix unnecessary killing of additional processes.
Date: Thu, 6 Sep 2018 15:56:15 +0200 [thread overview]
Message-ID: <20180906135615.GA14951@dhcp22.suse.cz> (raw)
In-Reply-To: <37b763c1-b83e-1632-3187-55fb360a914e@i-love.sakura.ne.jp>
On Thu 06-09-18 22:40:24, Tetsuo Handa wrote:
> On 2018/09/06 21:05, Michal Hocko wrote:
> >> If you are too busy, please show "the point of no-blocking" using source code
> >> instead. If such "the point of no-blocking" really exists, it can be executed
> >> by allocating threads.
> >
> > I would have to study this much deeper but I _suspect_ that we are not
> > taking any blocking locks right after we return from unmap_vmas. In
> > other words the place we used to have synchronization with the
> > oom_reaper in the past.
>
> See commit 97b1255cb27c551d ("mm,oom_reaper: check for MMF_OOM_SKIP before
> complaining"). Since this dependency is inode-based (i.e. irrelevant with
> OOM victims), waiting for this lock can livelock.
>
> So, where is safe "the point of no-blocking" ?
Ohh, right unlink_file_vma and its i_mmap_rwsem lock. As I've said I
have to think about that some more. Maybe we can split those into two parts.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-09-06 13:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-04 13:29 [PATCH 1/4] mm, oom: Remove wake_oom_reaper() Tetsuo Handa
2018-08-04 13:29 ` [PATCH 2/4] mm, oom: Check pending victims earlier in out_of_memory() Tetsuo Handa
2018-08-04 13:29 ` [PATCH 3/4] mm, oom: Remove unused "abort" path Tetsuo Handa
2018-08-04 13:29 ` [PATCH 4/4] mm, oom: Fix unnecessary killing of additional processes Tetsuo Handa
2018-08-06 13:45 ` Michal Hocko
2018-08-06 20:19 ` David Rientjes
2018-08-06 20:51 ` Michal Hocko
2018-08-09 20:16 ` David Rientjes
2018-08-10 9:07 ` Michal Hocko
2018-08-10 10:54 ` Tetsuo Handa
2018-08-10 11:16 ` Michal Hocko
2018-08-11 3:12 ` Tetsuo Handa
2018-08-14 11:33 ` Michal Hocko
2018-08-19 14:23 ` Tetsuo Handa
2018-08-20 5:54 ` Michal Hocko
2018-08-20 22:03 ` Tetsuo Handa
2018-08-21 6:16 ` Michal Hocko
2018-08-21 13:39 ` Tetsuo Handa
2018-08-19 23:45 ` David Rientjes
2018-08-20 6:07 ` Michal Hocko
2018-08-20 21:31 ` David Rientjes
2018-08-21 6:09 ` Michal Hocko
2018-08-21 17:20 ` David Rientjes
2018-08-22 8:03 ` Michal Hocko
2018-08-22 20:54 ` David Rientjes
2018-09-01 11:48 ` Tetsuo Handa
2018-09-06 11:35 ` Michal Hocko
2018-09-06 11:50 ` Tetsuo Handa
2018-09-06 12:05 ` Michal Hocko
2018-09-06 13:40 ` Tetsuo Handa
2018-09-06 13:56 ` Michal Hocko [this message]
2018-09-06 14:06 ` Tetsuo Handa
2018-09-06 14:16 ` Michal Hocko
2018-09-06 21:13 ` Tetsuo Handa
2018-09-07 11:10 ` Michal Hocko
2018-09-07 11:36 ` Tetsuo Handa
2018-09-07 11:51 ` Michal Hocko
2018-09-07 13:30 ` Tetsuo Handa
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