From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>,
torvalds@linux-foundation.org, guro@fb.com, rientjes@google.com,
hannes@cmpxchg.org, vdavydov.dev@gmail.com, tj@kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] mm,oom: Don't call schedule_timeout_killable() with oom_lock held.
Date: Thu, 31 May 2018 20:47:21 +0200 [thread overview]
Message-ID: <20180531184721.GU15278@dhcp22.suse.cz> (raw)
In-Reply-To: <7276d450-5e66-be56-3a17-0fc77596a3b6@i-love.sakura.ne.jp>
On Fri 01-06-18 00:23:57, Tetsuo Handa wrote:
> On 2018/05/31 19:44, Michal Hocko wrote:
> > On Thu 31-05-18 19:10:48, Tetsuo Handa wrote:
> >> On 2018/05/30 8:07, Andrew Morton wrote:
> >>> On Tue, 29 May 2018 09:17:41 +0200 Michal Hocko <mhocko@kernel.org> wrote:
> >>>
> >>>>> I suggest applying
> >>>>> this patch first, and then fix "mm, oom: cgroup-aware OOM killer" patch.
> >>>>
> >>>> Well, I hope the whole pile gets merged in the upcoming merge window
> >>>> rather than stall even more.
> >>>
> >>> I'm more inclined to drop it all. David has identified significant
> >>> shortcomings and I'm not seeing a way of addressing those shortcomings
> >>> in a backward-compatible fashion. Therefore there is no way forward
> >>> at present.
> >>>
> >>
> >> Can we apply my patch as-is first?
> >
> > No. As already explained before. Sprinkling new sleeps without a strong
> > reason is not acceptable. The issue you are seeing is pretty artificial
> > and as such doesn're really warrant an immediate fix. We should rather
> > go with a well thought trhough fix. In other words we should simply drop
> > the sleep inside the oom_lock for starter unless it causes some really
> > unexpected behavior change.
> >
>
> The OOM killer did not require schedule_timeout_killable(1) to return
> as long as the OOM victim can call __mmput(). But now the OOM killer
> requires schedule_timeout_killable(1) to return in order to allow the
> OOM victim to call __oom_reap_task_mm(). Thus, this is a regression.
>
> Artificial cannot become the reason to postpone my patch. If we don't care
> artificialness/maliciousness, we won't need to care Spectre/Meltdown bugs.
>
> I'm not sprinkling new sleeps. I'm just merging existing sleeps (i.e.
> mutex_trylock() case and !mutex_trylock() case) and updating the outdated
> comments.
Sigh. So what exactly is wrong with going simple and do
http://lkml.kernel.org/r/20180528124313.GC27180@dhcp22.suse.cz ?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-05-31 18:47 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-12 14:18 [PATCH] mm,oom: Don't call schedule_timeout_killable() with oom_lock held Tetsuo Handa
2018-05-15 9:16 ` Michal Hocko
2018-05-18 10:14 ` Tetsuo Handa
2018-05-18 12:20 ` Michal Hocko
2018-05-20 15:56 ` Tetsuo Handa
2018-05-22 6:18 ` Michal Hocko
2018-05-23 10:24 ` Tetsuo Handa
2018-05-23 11:57 ` Michal Hocko
2018-05-23 13:45 ` Tetsuo Handa
2018-05-23 14:56 ` Michal Hocko
2018-05-24 10:51 ` Tetsuo Handa
2018-05-24 11:50 ` Michal Hocko
2018-05-25 1:17 ` Tetsuo Handa
2018-05-25 8:31 ` Michal Hocko
2018-05-25 10:57 ` Tetsuo Handa
2018-05-25 11:42 ` Michal Hocko
2018-05-25 11:46 ` Tetsuo Handa
2018-05-28 12:43 ` Michal Hocko
2018-05-28 20:57 ` Tetsuo Handa
2018-05-29 7:17 ` Michal Hocko
2018-05-29 23:07 ` Andrew Morton
2018-05-31 10:10 ` Tetsuo Handa
2018-05-31 10:44 ` Michal Hocko
2018-05-31 15:23 ` Tetsuo Handa
2018-05-31 18:47 ` Michal Hocko [this message]
2018-06-01 1:21 ` Tetsuo Handa
2018-06-01 8:04 ` Michal Hocko
2018-06-01 15:28 ` Michal Hocko
2018-06-01 21:11 ` Andrew Morton
2018-06-04 7:04 ` Michal Hocko
2018-06-04 10:41 ` Tetsuo Handa
2018-06-04 11:22 ` Michal Hocko
2018-06-04 11:30 ` Tetsuo Handa
2018-06-06 9:02 ` David Rientjes
2018-06-06 13:37 ` Tetsuo Handa
2018-06-06 18:44 ` David Rientjes
2018-05-29 7:17 ` Michal Hocko
2018-05-29 8:16 ` Michal Hocko
2018-05-29 14:33 ` Tetsuo Handa
2018-05-29 17:18 ` Michal Hocko
2018-05-29 17:28 ` Michal Hocko
2018-05-31 16:31 ` [PATCH] mm, memcg, oom: fix pre-mature allocation failures kbuild test robot
-- strict thread matches above, loose matches on Subject: below --
2018-03-22 10:51 [PATCH] mm,oom: Don't call schedule_timeout_killable() with oom_lock held Tetsuo Handa
2018-03-22 11:45 ` Michal Hocko
2018-03-22 13:16 ` Tetsuo Handa
2018-01-22 13:46 Tetsuo Handa
2018-01-23 8:38 ` Michal Hocko
2018-01-23 12:07 ` Tetsuo Handa
2018-01-23 12:42 ` Michal Hocko
2018-01-24 13:28 ` Tetsuo Handa
2018-02-13 11:58 ` Tetsuo Handa
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