Re: [v5] powerpc/mm: Add page soft dirty tracking

On Thu, 2015-03-12 at 10:29:19 UTC, Laurent Dufour wrote:

User space checkpoint and restart tool (CRIU) needs the page's change
to be soft tracked. This allows to do a pre checkpoint and then dump
only touched pages.

This is done by using a newly assigned PTE bit (_PAGE_SOFT_DIRTY) when
the page is backed in memory, and a new _PAGE_SWP_SOFT_DIRTY bit when
the page is swapped out.

To introduce a new PTE _PAGE_SOFT_DIRTY bit value common to hash 4k
and hash 64k pte, the bits already defined in hash-*4k.h should be
shifted left by one.

The _PAGE_SWP_SOFT_DIRTY bit is dynamically put after the swap type in
the swap pte. A check is added to ensure that the bit is not
overwritten by _PAGE_HPTEFLAGS.

Signed-off-by: Laurent Dufour <redacted>
CC: Aneesh Kumar K.V <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/7207f43665b83ed7881c5111bc

cheers