Re: Memory management woes - order 1 allocation failures

From: Pekka Enberg
Date: Fri Feb 26 2010 - 09:02:01 EST


On Fri, Feb 26, 2010 at 1:32 PM, Frans Pop <elendil@xxxxxxxxx> wrote:
> Attached a long series of order 1 (!) page allocation failures with .33-rc7
> on an arm NAS box (running Debian unstable).
>
> The first failure occurred while running aptitude (Debian package manager)
> only ~20 minutes after booting the system, and I've seen that happen twice
> before.
>
> The other failures were all 1.5 days later while rsyncing a lot of music
> files (ogg/mp3) from another box to this one.
> They occurred when I was trying to also do something in an SSH session. The
> first ones from a simple 'sudo vi /etc/exports', some of the later ones
> while creating a new SSH session from my laptop.
>
> As can be seen from the attached munin graph [1] the system has only 256 MB
> memory, but that's quite normal for a simple NAS system. Only very little
> of that was in use by apps; most was being used for cache.
> The errors occurred in the area immediately above the "Thu 12:00" label,
> where the cache increases dramatically.
>
> Isn't it a bit strange that cache claims so much memory that real processes
> get into allocation failures?

All of the failed allocations seem to be GFP_ATOMIC so it's not _that_
strange. Dunno if anything changed recently. What's the last known
good kernel for you?
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