Re: VM issue causing high CPU loads

Mel Gorman
2009-08-26T11:08:08Z

On Mon, Aug 24, 2009 at 04:21:55PM -0700, Andrew Morton wrote:
> On Mon, 24 Aug 2009 16:23:22 +0200
> Yohan <kernel@yohan.staff.proxad.net> wrote:
>
> > Hi,
> >
> > Is someone have an idea for that :
> >
> > http://bugzilla.kernel.org/show_bug.cgi?id=14024
> >
>
> Please generate a kernel profile to work out where all the CPU tie is
> being spent. Documentation/basic_profiling.txt is a starting point.
>

In the absense of a profile, here is a total stab in the dark. Is this a
NUMA machine? If so, is /proc/sys/vm/zone_reclaim_mode set to 1 and does
setting it to 0 help?

This is based on a relatively recent bug where malloc() could stall for
long times with large amounts of CPU usage due to useless scanning in
page reclaim.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab