From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id CD7026B0012 for ; Wed, 25 May 2011 16:18:15 -0400 (EDT) Received: by pwi12 with SMTP id 12so52219pwi.14 for ; Wed, 25 May 2011 13:18:14 -0700 (PDT) MIME-Version: 1.0 From: Andrew Lutomirski Date: Wed, 25 May 2011 16:17:54 -0400 Message-ID: Subject: Easy portable testcase! (Re: Kernel falls apart under light memory pressure (i.e. linking vmlinux)) Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: minchan.kim@gmail.com, aarcange@redhat.com, kamezawa.hiroyu@jp.fujitsu.com, fengguang.wu@intel.com, andi@firstfloor.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mgorman@suse.de, hannes@cmpxchg.org, riel@redhat.com On Tue, May 24, 2011 at 8:43 PM, KOSAKI Motohiro wrote: > > Unfortnately, this log don't tell us why DM don't issue any swap io. ;-) > I doubt it's DM issue. Can you please try to make swap on out of DM? > > I can do one better: I can tell you how to reproduce the OOM in the comfort of your own VM without using dm_crypt or a Sandy Bridge laptop. This is on Fedora 15, but it really ought to work on any x86_64 distribution that has kvm. You'll probably want at least 6GB on your host machine because the VM wants 4GB ram. Here's how: Step 1: Clone git://gitorious.org/linux-test-utils/reproduce-annoying-mm-bug.git (You can browse here:) https://gitorious.org/linux-test-utils/reproduce-annoying-mm-bug Instructions to reproduce the mm bug: Step 2: Build Linux v2.6.38.6 with config-2.6.38.6 and the patch 0001-Minchan-patch-for-testing-23-05-2011.patch (both files are in the git repo) Step 3: cd back to reproduce-annoying-mm-bug Step 4: Type this. $ make $ qemu-kvm -m 4G -smp 2 -kernel /arch/x86/boot/bzImage -initrd initramfs.gz Step 5: Wait for the VM to boot (it's really fast) and then run ./repro_bug.sh. Step 6: Wait a bit and watch the fireworks. Note that it can take a couple minutes to reproduce the bug. Tested on my Sandy Bridge laptop and on a Xeon W3520. For whatever reason, on my laptop without the VM I can hit the bug almost instantaneously. Maybe it's because I'm using dm-crypt on my laptop. --Andy P.S. I think that the mk_trivial_initramfs.sh script is cute, and maybe I'll try to flesh it out and turn it into a real project some day. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org