[lkml]   [2013]   [Aug]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [patch 1/2] [PATCH] mm: Save soft-dirty bits on swapped pages
On Wed, 31 Jul 2013 00:41:55 +0400 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.

So the implication is that if another architecture wants to support
this (and, realistically, wants to support CRIU), that architecture
must find a spare pte bit to implement _PTE_SWP_SOFT_DIRTY. Yes?

 \ /
  Last update: 2013-08-07 22:41    [W:0.191 / U:0.908 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site