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From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: linux-mm@kvack.org, rientjes@google.com, oleg@redhat.com,
	vdavydov@parallels.com, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/6] mm, oom: do not loop over all tasks if there are no external tasks sharing mm
Date: Fri, 27 May 2016 09:15:08 +0200	[thread overview]
Message-ID: <20160527071507.GC27686@dhcp22.suse.cz> (raw)
In-Reply-To: <20160527064510.GA27686@dhcp22.suse.cz>

On Fri 27-05-16 08:45:10, Michal Hocko wrote:
[...]
> It is still an operation which is not needed for 99% of situations. So
> if we do not need it for correctness then I do not think this is worth
> bothering.

Since you have pointed out exit_mm vs. __exit_signal race yesterday I
was thinking how to make the check reliable. Even
atomic_read(mm->mm_users) > get_nr_threads() is not reliable and we can
miss other tasks just because the current thread group is mostly past
exit_mm. So far I couldn't find a way to tweak this around though.
I will think about it more but I am afraid that a flag would be really
needed afterall.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2016-05-27  7:15 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-26 12:40 [PATCH 0/5] Handle oom bypass more gracefully Michal Hocko
2016-05-26 12:40 ` [PATCH 1/6] mm, oom: do not loop over all tasks if there are no external tasks sharing mm Michal Hocko
2016-05-26 14:30   ` Tetsuo Handa
2016-05-26 14:59     ` Michal Hocko
2016-05-26 15:25       ` [PATCH 1/6] mm, oom: do not loop over all tasks if there are noexternal " Tetsuo Handa
2016-05-26 15:35         ` Michal Hocko
2016-05-26 16:14           ` [PATCH 1/6] mm, oom: do not loop over all tasks if there are no external " Tetsuo Handa
2016-05-27  6:45             ` Michal Hocko
2016-05-27  7:15               ` Michal Hocko [this message]
2016-05-27  8:03                 ` Michal Hocko
2016-05-26 12:40 ` [PATCH 2/6] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-05-26 12:40 ` [PATCH 3/6] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-05-27 11:18   ` Michal Hocko
2016-05-27 16:18     ` Vladimir Davydov
2016-05-30  7:07       ` Michal Hocko
2016-05-30  8:47         ` Vladimir Davydov
2016-05-30  9:39           ` Michal Hocko
2016-05-30 10:26             ` Vladimir Davydov
2016-05-30 11:11               ` Michal Hocko
2016-05-30 12:19                 ` Vladimir Davydov
2016-05-30 12:28                   ` Michal Hocko
2016-05-26 12:40 ` [PATCH 4/6] mm, oom: skip over vforked tasks Michal Hocko
2016-05-27 16:48   ` Vladimir Davydov
2016-05-30  7:13     ` Michal Hocko
2016-05-30  9:52       ` Michal Hocko
2016-05-30 10:40         ` Vladimir Davydov
2016-05-30 10:53           ` Michal Hocko
2016-05-30 12:03   ` Michal Hocko
2016-05-26 12:40 ` [PATCH 5/6] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-05-26 12:40 ` [PATCH 6/6] mm, oom: fortify task_will_free_mem Michal Hocko
2016-05-26 14:11   ` Tetsuo Handa
2016-05-26 14:23     ` Michal Hocko
2016-05-26 14:41       ` Tetsuo Handa
2016-05-26 14:56         ` Michal Hocko
2016-05-27 11:07   ` Michal Hocko
2016-05-27 16:00 ` [PATCH 0/5] Handle oom bypass more gracefully Michal Hocko

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