mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()
authorJianyu Zhan <nasa4836@gmail.com>
Wed, 4 Jun 2014 23:09:51 +0000 (16:09 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 4 Jun 2014 23:54:07 +0000 (16:54 -0700)
commitbea04b073292b2acb522c7c1aa67a4fc58151530
tree9d4efd221e0fa4b649cc6fbcfa19baa22cb3b3be
parente9ade569910a82614ff5f2c2cea2b65a8d785da4
mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()

mlocked_vma_newpage() is called with pte lock held(a spinlock), which
implies preemtion disabled, and the vm stat counter is not modified from
interrupt context, so we need not use an irq-safe mod_zone_page_state()
here, using a light-weight version __mod_zone_page_state() would be OK.

This patch also documents __mod_zone_page_state() and some of its
callsites.  The comment above __mod_zone_page_state() is from Hugh
Dickins, and acked by Christoph.

Most credits to Hugh and Christoph for the clarification on the usage of
the __mod_zone_page_state().

[akpm@linux-foundation.org: coding-style fixes]
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/internal.h
mm/rmap.c
mm/vmstat.c