mm: move anon_vma ref out from under CONFIG_foo
We need the anon_vma refcount unconditionally to simplify the anon_vma
lifetime rules.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index ad416af..873cd9e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -272,7 +272,7 @@
list_del(&anon_vma_chain->same_anon_vma);
/* We must garbage collect the anon_vma if it's empty */
- empty = list_empty(&anon_vma->head) && !anonvma_external_refcount(anon_vma);
+ empty = list_empty(&anon_vma->head) && !atomic_read(&anon_vma->refcount);
anon_vma_unlock(anon_vma);
if (empty) {
@@ -303,7 +303,7 @@
struct anon_vma *anon_vma = data;
spin_lock_init(&anon_vma->lock);
- anonvma_external_refcount_init(anon_vma);
+ atomic_set(&anon_vma->refcount, 0);
INIT_LIST_HEAD(&anon_vma->head);
}
@@ -1486,7 +1486,6 @@
return try_to_unmap_file(page, TTU_MUNLOCK);
}
-#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
/*
* Drop an anon_vma refcount, freeing the anon_vma and anon_vma->root
* if necessary. Be careful to do all the tests under the lock. Once
@@ -1495,8 +1494,8 @@
*/
void put_anon_vma(struct anon_vma *anon_vma)
{
- BUG_ON(atomic_read(&anon_vma->external_refcount) <= 0);
- if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->root->lock)) {
+ BUG_ON(atomic_read(&anon_vma->refcount) <= 0);
+ if (atomic_dec_and_lock(&anon_vma->refcount, &anon_vma->root->lock)) {
struct anon_vma *root = anon_vma->root;
int empty = list_empty(&anon_vma->head);
int last_root_user = 0;
@@ -1507,8 +1506,8 @@
* the refcount on the root and check if we need to free it.
*/
if (empty && anon_vma != root) {
- BUG_ON(atomic_read(&root->external_refcount) <= 0);
- last_root_user = atomic_dec_and_test(&root->external_refcount);
+ BUG_ON(atomic_read(&root->refcount) <= 0);
+ last_root_user = atomic_dec_and_test(&root->refcount);
root_empty = list_empty(&root->head);
}
anon_vma_unlock(anon_vma);
@@ -1520,7 +1519,6 @@
}
}
}
-#endif
#ifdef CONFIG_MIGRATION
/*