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

[Michael Ellerman]

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 <ldufour at linux.vnet.ibm.com>
> CC: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

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

cheers