From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: mhocko@kernel.org, nholland@tisys.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, clm@fb.com,
dsterba@suse.cz, linux-btrfs@vger.kernel.org
Subject: Re: OOM: Better, but still there on
Date: Wed, 21 Dec 2016 20:00:38 +0900 [thread overview]
Message-ID: <201612212000.EJJ21327.SFHOLQOtVFMOFJ@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20161221073658.GC16502@dhcp22.suse.cz>
Michal Hocko wrote:
> TL;DR
> there is another version of the debugging patch. Just revert the
> previous one and apply this one instead. It's still not clear what
> is going on but I suspect either some misaccounting or unexpeted
> pages on the LRU lists. I have added one more tracepoint, so please
> enable also mm_vmscan_inactive_list_is_low.
>
> Hopefully the additional data will tell us more.
>
> On Tue 20-12-16 03:08:29, Nils Holland wrote:
> > On Mon, Dec 19, 2016 at 02:45:34PM +0100, Michal Hocko wrote:
> >
> > > Unfortunatelly shrink_active_list doesn't have any tracepoint so we do
> > > not know whether we managed to rotate those pages. If they are referenced
> > > quickly enough we might just keep refaulting them... Could you try to apply
> > > the followin diff on top what you have currently. It should add some more
> > > tracepoint data which might tell us more. We can reduce the amount of
> > > tracing data by enabling only mm_vmscan_lru_isolate,
> > > mm_vmscan_lru_shrink_inactive and mm_vmscan_lru_shrink_active.
> >
> > So, the results are in! I applied your patch and rebuild the kernel,
> > then I rebooted the machine, set up tracing so that only the three
> > events you mentioned were being traced, and captured the output over
> > the network.
> >
> > Things went a bit different this time: The trace events started to
> > appear after a while and a whole lot of them were generated, but
> > suddenly they stopped. A short while later, we get
"cat /debug/trace/trace_pipe > /dev/udp/$ip/$port" stops reporting if
/bin/cat is disturbed by page fault and/or memory allocation needed for
sending UDP packets. Since netconsole can send UDP packets without involving
memory allocation, printk() is preferable than tracing under OOM.
>
> It is possible that you are hitting multiple issues so it would be
> great to focus at one at the time. The underlying problem might be
> same/similar in the end but this is hard to tell now. Could you try to
> reproduce and provide data for the OOM killer situation as well?
>
> > [ 1661.485568] btrfs-transacti: page alloction stalls for 611058ms, order:0, mode:0x2420048(GFP_NOFS|__GFP_HARDWALL|__GFP_MOVABLE)
> >
> > along with a backtrace and memory information, and then there was
> > silence.
>
> > When I walked up to the machine, it had completely died; it
> > wouldn't turn on its screen on key press any more, blindly trying to
> > reboot via SysRequest had no effect, but the caps lock LED also wasn't
> > blinking, like it normally does when a kernel panic occurs. Good
> > question what state it was in. The OOM reaper didn't really seem to
> > kick in and kill processes this time, it seems.
> >
> > The complete capture is up at:
> >
> > http://ftp.tisys.org/pub/misc/teela_2016-12-20.log.xz
>
> This is the stall report:
> [ 1661.485568] btrfs-transacti: page alloction stalls for 611058ms, order:0, mode:0x2420048(GFP_NOFS|__GFP_HARDWALL|__GFP_MOVABLE)
> [ 1661.485859] CPU: 1 PID: 1950 Comm: btrfs-transacti Not tainted 4.9.0-gentoo #4
>
> pid 1950 is trying to allocate for a _long_ time. Considering that this
> is the only stall report, this means that reclaim took really long so we
> didn't get to the page allocator for that long. It sounds really crazy!
warn_alloc() reports only if !__GFP_NOWARN.
We can report where they were looping using kmallocwd at
http://lkml.kernel.org/r/1478416501-10104-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
(and extend it to call printk() for reporting values using SystemTap which your
trace hooks would report, only during memory allocations are stalling, without
delay caused by page fault and/or memory allocation needed for sending UDP packets).
But if trying to reboot via SysRq-b did not work, I think that the system
was in hard lockup state. That would be a different problem.
By the way, Michal, I'm feeling strange because it seems to me that your
analysis does not refer to the implications of "x86_32 kernel". Maybe
you already referred x86_32 by "they are from the highmem zone" though.
next prev parent reply other threads:[~2016-12-21 11:01 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 [this message]
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
2016-12-16 19:50 ` Chris Mason
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