Messages in this thread | | | Date | Thu, 11 Nov 2010 14:25:27 +0000 | From | Mel Gorman <> | Subject | Re: [BUG] Commit d065bd81 severely regresses huge page allocation success rates |
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On Thu, Nov 11, 2010 at 04:25:00AM -0800, Michel Lespinasse wrote: > On Thu, Nov 11, 2010 at 4:15 AM, Mel Gorman <mel@csn.ul.ie> wrote: > > When testing 2.6.37-rc1, I noticed that huge page allocation success > > rates were severely impaired. Bisection showed that commit [d065bd81: mm: > > retry page fault when blocking on disk transfer] was the biggest factor. > > Reverting the patch confirmed this. Here are the results of a high-order > > allocation stress test. The vanilla kernel is 2.6.37-rc1 and the revert > > kernel has this commit removed with minor conflicts cleaned up. > [...] > > I have not digested what the patch is doing but am reporting it in case > > people familiar with the patch spot the problem quickly. > > There was a bug in that commit, which was fixed in > d88c0922fa0e2c021a028b310a641126c6d4b7dc > > I think this may explain the issue; compaction won't work well if > extra references are kept :/ >
Reclaim would not work either as it is effectively a leak.
> Can you check that this indeed solves your test case ? >
It does. Thanks very much.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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