mm: migration: share the anon_vma ref counts between KSM and page migration

For clarity of review, KSM and page migration have separate refcounts on
the anon_vma.  While clear, this is a waste of memory.  This patch gets
KSM and page migration to share their toys in a spirit of harmony.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman
2010-05-24 14:32:18 -07:00
committed by Linus Torvalds
parent 3f6c82728f
commit 7f60c214fd
4 changed files with 24 additions and 40 deletions

View File

@@ -601,7 +601,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
rcu_read_lock();
rcu_locked = 1;
anon_vma = page_anon_vma(page);
atomic_inc(&anon_vma->migrate_refcount);
atomic_inc(&anon_vma->external_refcount);
}
/*
@@ -643,7 +643,7 @@ skip_unmap:
rcu_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma && atomic_dec_and_lock(&anon_vma->migrate_refcount, &anon_vma->lock)) {
if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
int empty = list_empty(&anon_vma->head);
spin_unlock(&anon_vma->lock);
if (empty)