Messages in this thread | | | Date | Wed, 31 Jul 2013 12:16:12 +0400 | From | Pavel Emelyanov <> | Subject | Re: [patch 1/2] [PATCH] mm: Save soft-dirty bits on swapped pages |
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On 07/31/2013 12:41 AM, Cyrill Gorcunov wrote:
> Andy Lutomirski reported that in case if a page with _PAGE_SOFT_DIRTY > bit set get swapped out, the bit is getting lost and no longer > available when pte read back. > > To resolve this we introduce _PTE_SWP_SOFT_DIRTY bit which is > saved in pte entry for the page being swapped out. When such page > is to be read back from a swap cache we check for bit presence > and if it's there we clear it and restore the former _PAGE_SOFT_DIRTY > bit back. > > One of the problem was to find a place in pte entry where we can > save the _PTE_SWP_SOFT_DIRTY bit while page is in swap. The > _PAGE_PSE was chosen for that, it doesn't intersect with swap > entry format stored in pte. > > Reported-by: Andy Lutomirski <luto@amacapital.net> > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
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