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From: Michal Hocko <mhocko@kernel.org>
To: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Shakeel Butt <shakeelb@google.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>,
	linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fs, mm: account filp and names caches to kmemcg
Date: Thu, 26 Oct 2017 09:49:58 +0200	[thread overview]
Message-ID: <20171026074958.tmtxkyymmsqtgr7w@dhcp22.suse.cz> (raw)
In-Reply-To: <xr931slqdery.fsf@gthelen.svl.corp.google.com>

On Wed 25-10-17 15:49:21, Greg Thelen wrote:
> Johannes Weiner <hannes@cmpxchg.org> wrote:
> 
> > On Wed, Oct 25, 2017 at 09:00:57PM +0200, Michal Hocko wrote:
[...]
> >> So just to make it clear you would be OK with the retry on successful
> >> OOM killer invocation and force charge on oom failure, right?
> >
> > Yeah, that sounds reasonable to me.
> 
> Assuming we're talking about retrying within try_charge(), then there's
> a detail to iron out...
> 
> If there is a pending oom victim blocked on a lock held by try_charge() caller
> (the "#2 Locks" case), then I think repeated calls to out_of_memory() will
> return true until the victim either gets MMF_OOM_SKIP or disappears.

true. And oom_reaper guarantees that MMF_OOM_SKIP gets set in the finit
amount of time.

> So a force
> charge fallback might be a needed even with oom killer successful invocations.
> Or we'll need to teach out_of_memory() to return three values (e.g. NO_VICTIM,
> NEW_VICTIM, PENDING_VICTIM) and try_charge() can loop on NEW_VICTIM.

No we, really want to wait for the oom victim to do its job. The only
thing we should be worried about is when out_of_memory doesn't invoke
the reaper. There is only one case like that AFAIK - GFP_NOFS request. I
have to think about this case some more. We currently fail in that case
the request.

-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2017-10-26  7:50 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-05 22:21 [PATCH] fs, mm: account filp and names caches to kmemcg Shakeel Butt
2017-10-06  7:59 ` Michal Hocko
2017-10-06 19:33   ` Shakeel Butt
2017-10-09  6:24     ` Michal Hocko
2017-10-09 17:52       ` Greg Thelen
2017-10-09 18:04         ` Michal Hocko
2017-10-09 18:17           ` Michal Hocko
2017-10-10  9:10             ` Michal Hocko
2017-10-10 22:21               ` Shakeel Butt
2017-10-11  9:09                 ` Michal Hocko
2017-10-09 20:26         ` Johannes Weiner
2017-10-10  9:14           ` Michal Hocko
2017-10-10 14:17             ` Johannes Weiner
2017-10-10 14:24               ` Michal Hocko
2017-10-12 19:03                 ` Johannes Weiner
2017-10-12 23:57                   ` Greg Thelen
2017-10-13  6:51                     ` Michal Hocko
2017-10-13  6:35                   ` Michal Hocko
2017-10-13  7:00                     ` Michal Hocko
2017-10-13 15:24                       ` Michal Hocko
2017-10-24 12:18                         ` Michal Hocko
2017-10-24 17:54                           ` Johannes Weiner
2017-10-24 16:06                         ` Johannes Weiner
2017-10-24 16:22                           ` Michal Hocko
2017-10-24 17:23                             ` Johannes Weiner
2017-10-24 17:55                               ` Michal Hocko
2017-10-24 18:58                                 ` Johannes Weiner
2017-10-24 20:15                                   ` Michal Hocko
2017-10-25  6:51                                     ` Greg Thelen
2017-10-25  7:15                                       ` Michal Hocko
2017-10-25 13:11                                         ` Johannes Weiner
2017-10-25 14:12                                           ` Michal Hocko
2017-10-25 16:44                                             ` Johannes Weiner
2017-10-25 17:29                                               ` Michal Hocko
2017-10-25 18:11                                                 ` Johannes Weiner
2017-10-25 19:00                                                   ` Michal Hocko
2017-10-25 21:13                                                     ` Johannes Weiner
2017-10-25 22:49                                                       ` Greg Thelen
2017-10-26  7:49                                                         ` Michal Hocko [this message]
2017-10-26 12:45                                                           ` Tetsuo Handa
2017-10-26 14:31                                                         ` Johannes Weiner
2017-10-26 19:56                                                           ` Greg Thelen
2017-10-27  8:20                                                             ` Michal Hocko
2017-10-27 20:50                                               ` Shakeel Butt
2017-10-30  8:29                                                 ` Michal Hocko
2017-10-30 19:28                                                   ` Shakeel Butt
2017-10-31  8:00                                                     ` Michal Hocko
2017-10-31 16:49                                                       ` Johannes Weiner
2017-10-31 18:50                                                         ` Michal Hocko
2017-10-24 15:45                     ` Johannes Weiner
2017-10-24 16:30                       ` Michal Hocko
2017-10-10 23:32 ` Al Viro

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