Messages in this thread | | | Date | Wed, 24 Jul 2013 22:52:35 +0400 | From | Pavel Emelyanov <> | Subject | Re: [PATCH] mm: Save soft-dirty bits on swapped pages |
| |
On 07/24/2013 08:08 PM, 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: Pavel Emelyanov <xemul@parallels.com> > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Matt Mackall <mpm@selenic.com> > Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> > Cc: Marcelo Tosatti <mtosatti@redhat.com> > Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> > Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
| |