Messages in this thread | | | Date | Mon, 27 Oct 2008 17:22:16 +1100 | From | Dave Chinner <> | Subject | Re: Order 0 page allocation failure under heavy I/O load |
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On Mon, Oct 27, 2008 at 06:47:31AM +0100, Claudio Martins wrote: > On Sunday 26 October 2008, Dave Chinner wrote: > > > The host will hang for tens of seconds at a time with both CPU cores > > pegged at 100%, and eventually I get this in dmesg: > > > > [1304740.261506] linux: page allocation failure. order:0, mode:0x10000 > > [1304740.261516] Pid: 10705, comm: linux Tainted: P 2.6.26-1-amd64 > > Hello, > > Have you tried to increase vm.min_free_kbytes to something higher, that is > >=30000?
No, because I've found the XFS bug the workload was triggering so I don't need to run it anymore.
I reported the problem because it appears that we've reported an allocation failure without very much reclaim scanning (64 pages in DMA zone, 0 pages in DMA32 zone), and there is apparently pages available for allocation in the DMA zone:
1304740.262136] Node 0 DMA: 160*4kB 82*8kB 32*16kB 11*32kB 8*64kB 4*128kB 3*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB = 8048kB
So it appears that memory reclaim has not found the free pages it apparently has available....
Fundamentally, I/O from a single CPU to a single disk on a machine with 2GB RAM should not be able to cause allocation failures at all, especially when the I/O is pure data I/O to a single file. Something in the default config is busted if I can do that, and that's why I reported the bug.
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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