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    SubjectRe: [PATCH 04/14] mm,migration: Allow the migration of PageSwapCache pages
    On Sat, Apr 24, 2010 at 11:52:27AM +0100, Mel Gorman wrote:
    > I think you're right. This is a new bug introduced by the anon_vma changes. On
    > the plus side, it means we don't have to worry about -stable.

    Correct, no worry about -stable.

    > > vma_adjust already takes the anon_vma->lock and of course I also
    > > further verified that trying to apply your snippet to vma_adjust
    > > results in immediately deadlock as the very same lock is already taken
    > > in my tree as it's the same anon-vma (simpler).
    > Yes, I expected that. Previously, there was only one anon_vma so if you
    > double-take the lock, bad things happen.
    > > So aa.git will be
    > > immune from these bugs for now.
    > >
    > It should be. I expect that's why you have never seen the bugon in
    > swapops.

    Correct, I never seen it, and I keep it under very great stress with
    swap storms of hugepages, lots of I/O and khugepaged at 100% cpu.

    Also keep in mind expand_downwards which also adjusts
    vm_start/vm_pgoff the same way (and without mmap_sem write mode).

     \ /
      Last update: 2010-04-24 13:17    [W:0.020 / U:139.680 seconds]
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