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| author |   Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-03-22 16:32:49 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-22 17:44:03 -0700 |
| commit | 01d8b20dec5f4019283e244aba50ba86fe6ead6e (patch) | |
| tree | 738a2e675547de61f74d6f4019dd5830c40446dd /include/linux/rmap.h | |
| parent | mm: move anon_vma ref out from under CONFIG_foo (diff) | |
| download | linux-dev-01d8b20dec5f4019283e244aba50ba86fe6ead6e.tar.xz linux-dev-01d8b20dec5f4019283e244aba50ba86fe6ead6e.zip | |
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.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index fd56111a52c1..830e65dc01ee 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 */ |