mm: thp: set the accessed flag for old pages on access fault
authorWill Deacon <will.deacon@arm.com>
Wed, 12 Dec 2012 00:01:27 +0000 (16:01 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 12 Dec 2012 01:22:24 +0000 (17:22 -0800)
commita1dd450bcb1a05e8218b9aac0ee36f8755d8a140
treea46f3306e3802b59ed5df6eef0e03b8b11cca30c
parenteb2db439a3203ae86c35ad277ac4a3268a94baa1
mm: thp: set the accessed flag for old pages on access fault

On x86 memory accesses to pages without the ACCESSED flag set result in
the ACCESSED flag being set automatically.  With the ARM architecture a
page access fault is raised instead (and it will continue to be raised
until the ACCESSED flag is set for the appropriate PTE/PMD).

For normal memory pages, handle_pte_fault will call pte_mkyoung
(effectively setting the ACCESSED flag).  For transparent huge pages,
pmd_mkyoung will only be called for a write fault.

This patch ensures that faults on transparent hugepages which do not
result in a CoW update the access flags for the faulting pmd.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/huge_mm.h
mm/huge_memory.c
mm/memory.c