Re: [PATCH 0/5] Reduce GFP_ATOMIC allocation failures, candidate fix V3

Mel Gorman
2009-11-16T09:53:05Z

On Sun, Nov 15, 2009 at 01:07:21PM +0100, Karol Lewandowski wrote:
> On Thu, Nov 12, 2009 at 07:30:30PM +0000, Mel Gorman wrote:
>
> > [Bug #14265] ifconfig: page allocation failure. order:5, mode:0x8020 w/ e100
>
> > Patches 1-3 should be tested first. The testing I've done shows that the
> > page allocator and behaviour of congestion_wait() is more in line with
> > 2.6.30 than the vanilla kernels.
> >
> > It'd be nice to have 2 more tests, applying each patch on top noting any
> > behaviour change. i.e. ideally there would be results for
> >
> > o patches 1+2+3
> > o patches 1+2+3+4
> > o patches 1+2+3+4+5
> >
> > Of course, any tests results are welcome. The rest of the mail is the
> > results of my own tests.
>
> I've tried testing 3+4+5 against 2.6.32-rc7 (1+2 seem to be in
> mainline) and got failure. I've noticed something strange (I think).
> I was unable to trigger failures when system was under heavy memory
> pressure (i.e. my testing - gitk, firefoxes, etc.). When I killed
> almost all memory hogs, put system into sleep and resumed -- it
> failed. free(1) showed:
>
> total used free shared buffers cached
> Mem: 255240 194052 61188 0 4040 49364
> -/+ buffers/cache: 140648 114592
> Swap: 514040 72712 441328
>
>
> Is that ok? Wild guess -- maybe kswapd doesn't take fragmentation (or
> other factors) into account as hard as it used to in 2.6.30?
>

That's a lot of memory free. I take it the order-5 GFP_ATOMIC allocation
failed. What was the dmesg for it please?

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