Messages in this thread | | | Date | Thu, 17 May 2007 11:02:51 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 0/5] make slab gfp fair |
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On Thu, 17 May 2007, Matt Mackall wrote:
> Simply stated, the problem is sometimes it's impossible to free memory > without allocating more memory. Thus we must keep enough protected > reserve that we can guarantee progress. This is what mempools are for > in the regular I/O stack. Unfortunately, mempools are a bad match for > network I/O. > > It's absolutely correct that performance doesn't matter in the case > this patch is addressing. All that matters is digging ourselves out of > OOM. The box either survives the crisis or it doesn't.
Well we fail allocations in order to do so and these allocations may be even nonatomic allocs. Pretty dangerous approach.
> It's also correct that we should hardly ever get into a situation > where we trigger this problem. But such cases are still fairly easy to > trigger in some workloads. Swap over network is an excellent example, > because we typically don't start swapping heavily until we're quite > low on freeable memory.
Is it not possible to avoid failing allocs? Instead put processes to sleep? Run synchrononous reclaim?
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