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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-03-22 16:32:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-22 17:44:03 -0700
commit01d8b20dec5f4019283e244aba50ba86fe6ead6e (patch)
tree738a2e675547de61f74d6f4019dd5830c40446dd /include/linux/rmap.h
parent83813267c699ab11cc65a6d9d0f42db42f0862b3 (diff)
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mm: simplify anon_vma refcounts
This patch changes the anon_vma refcount to be 0 when the object is free. It does this by adding 1 ref to being in use in the anon_vma structure (iow. the anon_vma->head list is not empty). This allows a simpler release scheme without having to check both the refcount and the list as well as avoids taking a ref for each entry on the list. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> 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>
Diffstat (limited to 'include/linux/rmap.h')
-rw-r--r--include/linux/rmap.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index fd56111a52c..830e65dc01e 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -73,7 +73,13 @@ static inline void get_anon_vma(struct anon_vma *anon_vma)
atomic_inc(&anon_vma->refcount);
}
-void put_anon_vma(struct anon_vma *);
+void __put_anon_vma(struct anon_vma *anon_vma);
+
+static inline void put_anon_vma(struct anon_vma *anon_vma)
+{
+ if (atomic_dec_and_test(&anon_vma->refcount))
+ __put_anon_vma(anon_vma);
+}
static inline struct anon_vma *page_anon_vma(struct page *page)
{
@@ -116,7 +122,6 @@ void unlink_anon_vmas(struct vm_area_struct *);
int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
void __anon_vma_link(struct vm_area_struct *);
-void anon_vma_free(struct anon_vma *);
static inline void anon_vma_merge(struct vm_area_struct *vma,
struct vm_area_struct *next)
@@ -125,6 +130,8 @@ static inline void anon_vma_merge(struct vm_area_struct *vma,
unlink_anon_vmas(next);
}
+struct anon_vma *page_get_anon_vma(struct page *page);
+
/*
* rmap interfaces called when adding or removing pte of page
*/