From: Michal Hocko <mhocko@suse.cz>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan@kernel.org>,
Rik van Riel <riel@redhat.com>, Ying Han <yinghan@google.com>,
Greg Thelen <gthelen@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH mmotm] memcg: further prevent OOM with too many dirty pages
Date: Tue, 17 Jul 2012 08:33:01 +0200 [thread overview]
Message-ID: <20120717063301.GA25435@tiehlicka.suse.cz> (raw)
In-Reply-To: <alpine.LSU.2.00.1207162135590.19938@eggly.anvils>
On Mon 16-07-12 21:52:51, Hugh Dickins wrote:
> On Mon, 16 Jul 2012, Michal Hocko wrote:
> > On Mon 16-07-12 01:35:34, Hugh Dickins wrote:
> > > But even so, the test still OOMs sometimes: when originally testing
> > > on 3.5-rc6, it OOMed about one time in five or ten; when testing
> > > just now on 3.5-rc6-mm1, it OOMed on the first iteration.
> > >
> > > This residual problem comes from an accumulation of pages under
> > > ordinary writeback, not marked PageReclaim, so rightly not causing
> > > the memcg check to wait on their writeback: these too can prevent
> > > shrink_page_list() from freeing any pages, so many times that memcg
> > > reclaim fails and OOMs.
> >
> > I guess you managed to trigger this with 20M limit, right?
>
> That's right.
>
> > I have tested
> > with different group sizes but the writeback didn't trigger for most of
> > them and all the dirty data were flushed from the reclaim.
>
> I didn't examine writeback stats to confirm, but I guess that just
> occasionally it managed to come in and do enough work to confound us.
>
> > Have you used any special setting the dirty ratio?
>
> No, I wasn't imaginative enough to try that.
>
> > Or was it with xfs (IIUC that one
> > does ignore writeback from the direct reclaim completely).
>
> No, just ext4 at that point.
>
> I have since tested the final patch with ext4, ext3 (by ext3 driver
> and by ext4 driver), ext2 (by ext2 driver and by ext4 driver), xfs,
> btrfs, vfat, tmpfs (with swap on the USB stick) and block device:
> about an hour on each, no surprises, all okay.
>
> But I didn't experiment beyond the 20M memcg.
Great coverage anyway. Thanks a lot Hugh!
>
> Hugh
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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next prev parent reply other threads:[~2012-07-17 6:33 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-19 14:50 [PATCH -mm] memcg: prevent from OOM with too many dirty pages Michal Hocko
2012-06-19 22:00 ` Andrew Morton
2012-06-20 8:27 ` Michal Hocko
2012-06-20 9:20 ` Mel Gorman
2012-06-20 9:55 ` Fengguang Wu
2012-06-20 9:59 ` Michal Hocko
2012-06-20 10:11 ` [PATCH v2 " Michal Hocko
2012-07-12 1:57 ` Hugh Dickins
2012-07-12 2:21 ` Andrew Morton
2012-07-12 3:13 ` Hugh Dickins
2012-07-12 7:05 ` Michal Hocko
2012-07-12 21:13 ` Andrew Morton
2012-07-12 22:42 ` Hugh Dickins
2012-07-13 8:21 ` Michal Hocko
2012-07-16 8:30 ` Hugh Dickins
2012-07-16 8:35 ` [PATCH mmotm] memcg: further prevent " Hugh Dickins
2012-07-16 9:26 ` Michal Hocko
2012-07-17 4:52 ` Hugh Dickins
2012-07-17 6:33 ` Michal Hocko [this message]
2012-07-16 21:08 ` Andrew Morton
2012-07-16 8:10 ` [PATCH v2 -mm] memcg: prevent from " Hugh Dickins
2012-07-16 8:48 ` Michal Hocko
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