Re: [PATCH 3/9] powerpc/mm: Add _PAGE_DEVMAP for ppc64.

Oliver O'Halloran [off-list ref] writes:

From: "Aneesh Kumar K.V" <redacted>

Add a _PAGE_DEVMAP bit for PTE and DAX PMD entires. PowerPC doesn't
currently support PUD faults so we haven't extended it to the PUD
level.

Cc: Aneesh Kumar K.V <redacted>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

Few changes we would need. We will now need to make sure a devmap
pmd entry is not confused with THP. ie,

we should compare against _PAGE_PTE and _PAGE_DEVMAP in
pmd_trans_huge(). hash already has one bit we use to differentiate
between hugetlb and THP. May be we can genarlize this and come up with a
way to differentiate THP, HUGETLB,pmd DEVMAP entries ?


also I don't see you handing get_user_pages_fast() ?


-aneesh