Date: Mon, 21 Dec 2015 12:14:00 +0100
From: Marcin Szewczyk <Marcin.Szewczyk@wodny.org>
To: linux-kernel@vger.kernel.org
Subject: OOM killer kicks in after minutes or never
Message-ID: <20151221111400.GC3060@orkisz>
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Hi,

In 2010 I noticed that viewing many GIFs in a row using gpicview renders
my Linux unresponsive. There is very little I can do in such a
situation. Rarely after some minutes the OOM killer kicks in and saves
the day. Nevertheless, usually I end up using Alt+SysRq+B.

This is the second computer I can observe this problem on. First was
Asus EeePC 1000 with Atom N270 and now I have Lenovo S210 with Celeron
1037U.

What happens is gpicview exhausting whole available memory in such a
pattern that userspace becomes unresponsive. I cannot switch to another
terminal either. I have written a tool that allocates memory in a very
similar way using GDK -- https://github.com/wodny/crasher.

I have also uploaded some logs to the repository -- top, iostat (showing
a lot of reads during an episode), dmesg.

I suppose the OS starts to oscillate between freeing memory, cleaning
caches and buffers, and loading some new data (see iostat logs).

Currently I am using Debian Jessie with the following kernel:
3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64 GNU/Linux

I can observe the most impressive effects on my physical machine
(logs/ph-*). On a VM (logs/vm-*) usually the OOM killer kills the
process after a short time (5-120 seconds).

Possible factors differentiating cases of recovering in seconds from
recoveries after minutes (or never):
- another memory-consuming process running (e.g. Firefox),
- physical machine or a VM (see dmesg logs),
- chipset and associated kernel functions (see dmesg logs).

Things that seem irrelevant (after testing):
- running the application in Xorg or a TTY,
- LUKS encryption of the root filesystem,
- vm.oom_kill_allocating_task setting.

What can I do to diagnose the problem further?

-- 
Marcin Szewczyk                       http://wodny.org
mailto:Marcin.Szewczyk@wodny.borg  <- remove b / usuń b
xmpp:wodny@ubuntu.pl                  xmpp:wodny@jabster.pl
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