From: Michal Hocko <mhocko@kernel.org>
To: Chris Mason <clm@fb.com>
Cc: Nils Holland <nholland@tisys.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
David Sterba <dsterba@suse.cz>,
linux-btrfs@vger.kernel.org
Subject: Re: OOM: Better, but still there on 4.9
Date: Sat, 17 Dec 2016 00:31:11 +0100 [thread overview]
Message-ID: <20161216233111.GA23392@dhcp22.suse.cz> (raw)
In-Reply-To: <4e87e963-154a-df2c-80a4-ecc6d898f9a8@fb.com>
On Fri 16-12-16 17:47:25, Chris Mason wrote:
> On 12/16/2016 05:14 PM, Michal Hocko wrote:
> > On Fri 16-12-16 13:15:18, Chris Mason wrote:
> > > On 12/16/2016 02:39 AM, Michal Hocko wrote:
> > [...]
> > > > I believe the right way to go around this is to pursue what I've started
> > > > in [1]. I will try to prepare something for testing today for you. Stay
> > > > tuned. But I would be really happy if somebody from the btrfs camp could
> > > > check the NOFS aspect of this allocation. We have already seen
> > > > allocation stalls from this path quite recently
> > >
> > > Just double checking, are you asking why we're using GFP_NOFS to avoid going
> > > into btrfs from the btrfs writepages call, or are you asking why we aren't
> > > allowing highmem?
> >
> > I am more interested in the NOFS part. Why cannot this be a full
> > GFP_KERNEL context? What kind of locks we would lock up when recursing
> > to the fs via slab shrinkers?
> >
>
> Since this is our writepages call, any jump into direct reclaim would go to
> writepage, which would end up calling the same set of code to read metadata
> blocks, which would do a GFP_KERNEL allocation and end up back in writepage
> again.
But we are not doing pageout on the page cache from the direct reclaim
for a long time. So basically the only way to recurse back to the fs
code is via slab ([di]cache) shrinkers. Are those a problem as well?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-12-16 23:31 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-15 22:57 OOM: Better, but still there on 4.9 Nils Holland
2016-12-16 7:39 ` Michal Hocko
2016-12-16 15:58 ` OOM: Better, but still there on Michal Hocko
2016-12-16 15:58 ` [PATCH 1/2] mm: consolidate GFP_NOFAIL checks in the allocator slowpath Michal Hocko
2016-12-16 15:58 ` [PATCH 2/2] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically Michal Hocko
2016-12-16 17:31 ` Johannes Weiner
2016-12-16 22:12 ` Michal Hocko
2016-12-17 11:17 ` Tetsuo Handa
2016-12-18 16:37 ` Michal Hocko
2016-12-16 18:47 ` OOM: Better, but still there on Nils Holland
2016-12-17 0:02 ` Michal Hocko
2016-12-17 12:59 ` Nils Holland
2016-12-17 14:44 ` Tetsuo Handa
2016-12-17 17:11 ` Nils Holland
2016-12-17 21:06 ` Nils Holland
2016-12-18 5:14 ` Tetsuo Handa
2016-12-19 13:45 ` Michal Hocko
2016-12-20 2:08 ` Nils Holland
2016-12-21 7:36 ` Michal Hocko
2016-12-21 11:00 ` Tetsuo Handa
2016-12-21 11:16 ` Michal Hocko
2016-12-21 14:04 ` Chris Mason
2016-12-22 10:10 ` Nils Holland
2016-12-22 10:27 ` Michal Hocko
2016-12-22 10:35 ` Nils Holland
2016-12-22 10:46 ` Tetsuo Handa
2016-12-22 19:17 ` Michal Hocko
2016-12-22 21:46 ` Nils Holland
2016-12-23 10:51 ` Michal Hocko
2016-12-23 12:18 ` Nils Holland
2016-12-23 12:57 ` Michal Hocko
2016-12-23 14:47 ` [RFC PATCH] mm, memcg: fix (Re: OOM: Better, but still there on) Michal Hocko
2016-12-23 22:26 ` Nils Holland
2016-12-26 12:48 ` Michal Hocko
2016-12-26 18:57 ` Nils Holland
2016-12-27 8:08 ` Michal Hocko
2016-12-27 11:23 ` Nils Holland
2016-12-27 11:27 ` Michal Hocko
2016-12-27 15:55 ` Michal Hocko
2016-12-27 16:28 ` [PATCH] mm, vmscan: consider eligible zones in get_scan_count kbuild test robot
2016-12-28 8:51 ` Michal Hocko
2016-12-27 19:33 ` [RFC PATCH] mm, memcg: fix (Re: OOM: Better, but still there on) Nils Holland
2016-12-28 8:57 ` Michal Hocko
2016-12-29 1:20 ` Minchan Kim
2016-12-29 9:04 ` Michal Hocko
2016-12-30 2:05 ` Minchan Kim
2016-12-30 10:40 ` Michal Hocko
2016-12-29 0:31 ` Minchan Kim
2016-12-29 0:48 ` Minchan Kim
2016-12-29 8:52 ` Michal Hocko
2016-12-30 10:19 ` Mel Gorman
2016-12-30 11:05 ` Michal Hocko
2016-12-30 12:43 ` Mel Gorman
2016-12-25 22:25 ` [lkp-developer] [mm, memcg] d18e2b2aca: WARNING:at_mm/memcontrol.c:#mem_cgroup_update_lru_size kernel test robot
2016-12-26 12:26 ` Michal Hocko
2016-12-26 12:50 ` Michal Hocko
2016-12-18 0:28 ` OOM: Better, but still there on Xin Zhou
2016-12-16 18:15 ` OOM: Better, but still there on 4.9 Chris Mason
2016-12-16 22:14 ` Michal Hocko
2016-12-16 22:47 ` Chris Mason
2016-12-16 23:31 ` Michal Hocko [this message]
2016-12-16 19:50 ` Chris Mason
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