Re: [PATCH] mm: Save soft-dirty bits on swapped pages

From: Cyrill Gorcunov
Date: Wed Jul 24 2013 - 13:17:36 EST


On Wed, Jul 24, 2013 at 10:06:53AM -0700, Andy Lutomirski wrote:
> > Hi Andy, if I understand you correctly "file-backed pages" are carried
> > in pte with _PAGE_FILE bit set and the swap soft-dirty bit won't be
> > used on them but _PAGE_SOFT_DIRTY will be set on write if only I've
> > not missed something obvious (Pavel?).
>
> If I understand this stuff correctly, the vmscan code calls
> try_to_unmap when it reclaims memory, which makes its way into
> try_to_unmap_one, which clears the pte (and loses the soft-dirty bit).

Indeed, I was so stareing into swap that forgot about files. I'll do
a separate patch for that, thanks!
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