From: Chris Mason <clm@fb.com>
To: Michal Hocko <mhocko@kernel.org>
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: Fri, 16 Dec 2016 17:47:25 -0500 [thread overview]
Message-ID: <4e87e963-154a-df2c-80a4-ecc6d898f9a8@fb.com> (raw)
In-Reply-To: <20161216221420.GF7645@dhcp22.suse.cz>
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.
We'd also have issues with blowing through transaction reservations
since the writepage recursion would have to nest into the running
transaction.
-chris
next prev parent reply other threads:[~2016-12-16 22:47 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 [this message]
2016-12-16 23:31 ` Michal Hocko
2016-12-16 19:50 ` Chris Mason
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