thp: do_huge_pmd_wp_page(): handle huge zero page
authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Wed, 12 Dec 2012 21:50:54 +0000 (13:50 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 13 Dec 2012 01:38:31 +0000 (17:38 -0800)
commit93b4796dede916de74b21fbd637588da6a99a7ec
tree3833de6051bb1b8d361a614743aafa56b43902e1
parentfc9fe822f7112db23e51e2be3b886f5d8f0afdb6
thp: do_huge_pmd_wp_page(): handle huge zero page

On write access to huge zero page we alloc a new huge page and clear it.

If ENOMEM, graceful fallback: we create a new pmd table and set pte around
fault address to newly allocated normal (4k) page.  All other ptes in the
pmd set to normal zero page.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mm.h
mm/huge_memory.c
mm/memory.c