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    SubjectRe: 2.6.22-rc4-mm1
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    On Wed, 2007-06-06 at 19:06 +0200, Peter Zijlstra wrote:
    > On Wed, 2007-06-06 at 09:35 -0700, William Lee Irwin III wrote:
    > > On Wed, Jun 06, 2007 at 05:26:49PM +0100, Mel Gorman wrote:
    > > > I do not believe this is Nick's problem. I encountered the same issue and
    > > > the bisect ended up here;
    > > > # BISECT HERE
    > > > mm-variable-length-argument-support.patch
    > > > mm-variable-length-argument-support-fix.patch
    > > > # BISECT BAD
    > > > Reverting those two patches boots ok on my standalone x86 laptop.
    > > > Patch authors cc'd. I have not read the patches yet to see what might
    > > > be the problem.
    > >
    > > I found this a while ago and peterz already has a tentative fix for it at
    > > http://programming.kicks-ass.net/kernel-patches/max_arg_pages/move_anon_vma.patch
    > > I'm sure he himself will chime in with more/better code when he returns.
    >
    > Ah, yes indeed. We were discussing wether it would be better to update
    > page->index (as this patch does) or not change vma->vm_pgoff. Bill
    > argued that the latter would be safe, it would just limit the merge
    > capabilities of the anon vma (and the stack rarely, if ever, merges
    > anyway).
    >
    > I myself an not quite sure on the effects of ->vm_pgoff of anon vmas
    > yet.

    Ok, from what I can make of it, nobody relies on the value of
    vma->vm_pgoff for anon vmas as long as the following invariant is kept:

    vaddr = vma->vm_start + (page->index - vma->vm_pgoff)*PAGE_SIZE

    So the proper thing to do is not change vm_pgoff.

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