Re: [PATCH 3/3] mm,migration: Remove straggling migration PTEswhen page tables are being moved after the VMA has already moved

[Andrea Arcangeli]

On Wed, Apr 28, 2010 at 10:29:28AM +0900, KAMEZAWA Hiroyuki wrote:
> Hmm..Mel's patch 2/3 takes vma->anon_vma->lock in vma_adjust(),
> so this patch clears vma->anon_vma...

yep, it should be safe with patch 2 applied too. And I'm unsure why Mel's
patch locks the anon_vma also when vm_start != start. See the other
email I sent about patch 2.

> I think we can unlock this just after move_page_tables().

Checking this, I can't see where exactly is vma->vm_pgoff adjusted
during the atomic section I protected with the anon_vma->lock?
For a moment it looks like these pages become unmovable.

I guess this is why I thought initially that it was move_page_tables
to adjust the page->index. If it doesn't then the vma->vm_pgoff has to
be moved down of shift >>PAGE_SHIFT and it doesn't seem to be
happening which is an unrelated bug.
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