Re: [PATCH 0/5] Candidate fix for increased number of GFP_ATOMIC failures V2

[Mel Gorman <mel@csn.ul.ie>]

On Fri, Nov 06, 2009 at 07:03:23AM +0100, Tobias Diedrich wrote:
> Mel Gorman wrote:
> > [No BZ ID] Kernel crash on 2.6.31.x (kcryptd: page allocation failure..)
> > 	This apparently is easily reproducible, particular in comparison to
> > 	the other reports. The point of greatest interest is that this is
> > 	order-0 GFP_ATOMIC failures. Sven, I'm hoping that you in particular
> > 	will be able to follow the tests below as you are the most likely
> > 	person to have an easily reproducible situation.
> 
> I've also seen order-0 failures on 2.6.31.5:
> Note that this is with a one process hogging and mlocking memory and
> min_free_kbytes reduced to 100 to reproduce the problem more easily.
> 

Is that a vanilla, with patches 1-3 applied or both?

> I tried bisecting the issue, but in the end without memory pressure
> I can't reproduce it reliably and with the above mentioned pressure
> I get allocation failures even on 2.6.30.o
> 

To be honest, it's not entirely unexpected with min_free_kbytes set that
low. The system should cope with a certain amount of pressure but with
pressure and a low min_free_kbytes, the system will simply be reacting
too late to free memory in the non-atomic paths.

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

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