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 08:45:10 +0200 [thread overview]
Message-ID: <20160527064510.GA27686@dhcp22.suse.cz> (raw)
In-Reply-To: <201605270114.IEI48969.MFFtFOJLQOOHSV@I-love.SAKURA.ne.jp>
On Fri 27-05-16 01:14:35, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > On Fri 27-05-16 00:25:23, Tetsuo Handa wrote:
> > > I think that remembering whether this mm might be shared between
> > > multiple thread groups at clone() time (i.e. whether
> > > clone(CLONE_VM without CLONE_SIGHAND) was ever requested on this mm)
> > > is safe (given that that thread already got SIGKILL or is exiting).
> >
> > I was already playing with that idea but I didn't want to add anything
> > to the fork path which is really hot. This patch is not really needed
> > for the rest. It just felt like a nice optimization. I do not think it
> > is worth deeper changes in the fast paths.
>
> "[PATCH 6/6] mm, oom: fortify task_will_free_mem" depends on [PATCH 1/6].
> You will need to update [PATCH 6/6].
>
> It seems to me that [PATCH 6/6] resembles
> http://lkml.kernel.org/r/201605250005.GHH26082.JOtQOSLMFFOFVH@I-love.SAKURA.ne.jp .
> I think we will be happy if we can speed up mm_is_reapable() test using
> "whether this mm might be shared between multiple thread groups" flag.
> I don't think updating such flag at clone() is too heavy operation to add.
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.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-05-27 6:45 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 [this message]
2016-05-27 7:15 ` Michal Hocko
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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