The normal code pattern used in the kernel is: get/put.
Reviewed-by: KAMEZAWA Hiroyuki <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
---
include/linux/rmap.h | 4 ++--
mm/ksm.c | 23 +++++------------------
mm/migrate.c | 4 ++--
mm/rmap.c | 4 ++--
4 files changed, 11 insertions(+), 24 deletions(-)
Index: linux-2.6/include/linux/rmap.h
===================================================================
--- linux-2.6.orig/include/linux/rmap.h
+++ linux-2.6/include/linux/rmap.h
@@ -87,7 +87,7 @@ static inline void get_anon_vma(struct a
atomic_inc(&anon_vma->external_refcount);
}
-void drop_anon_vma(struct anon_vma *);
+void put_anon_vma(struct anon_vma *);
#else
static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
{
@@ -102,7 +102,7 @@ static inline void get_anon_vma(struct a
{
}
-static inline void drop_anon_vma(struct anon_vma *anon_vma)
+static inline void put_anon_vma(struct anon_vma *anon_vma)
{
}
#endif /* CONFIG_KSM */
Index: linux-2.6/mm/ksm.c
===================================================================
--- linux-2.6.orig/mm/ksm.c
+++ linux-2.6/mm/ksm.c
@@ -301,20 +301,6 @@ static inline int in_stable_tree(struct
return rmap_item->address & STABLE_FLAG;
}
-static void hold_anon_vma(struct rmap_item *rmap_item,
- struct anon_vma *anon_vma)
-{
- rmap_item->anon_vma = anon_vma;
- get_anon_vma(anon_vma);
-}
-
-static void ksm_drop_anon_vma(struct rmap_item *rmap_item)
-{
- struct anon_vma *anon_vma = rmap_item->anon_vma;
-
- drop_anon_vma(anon_vma);
-}
-
/*
* ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's
* page tables after it has passed through ksm_exit() - which, if necessary,
@@ -397,7 +383,7 @@ static void break_cow(struct rmap_item *
* It is not an accident that whenever we want to break COW
* to undo, we also need to drop a reference to the anon_vma.
*/
- ksm_drop_anon_vma(rmap_item);
+ put_anon_vma(rmap_item->anon_vma);
down_read(&mm->mmap_sem);
if (ksm_test_exit(mm))
@@ -466,7 +452,7 @@ static void remove_node_from_stable_tree
ksm_pages_sharing--;
else
ksm_pages_shared--;
- ksm_drop_anon_vma(rmap_item);
+ put_anon_vma(rmap_item->anon_vma);
rmap_item->address &= PAGE_MASK;
cond_resched();
}
@@ -554,7 +540,7 @@ static void remove_rmap_item_from_tree(s
else
ksm_pages_shared--;
- ksm_drop_anon_vma(rmap_item);
+ put_anon_vma(rmap_item->anon_vma);
rmap_item->address &= PAGE_MASK;
} else if (rmap_item->address & UNSTABLE_FLAG) {
@@ -949,7 +935,8 @@ static int try_to_merge_with_ksm_page(st
goto out;
/* Must get reference to anon_vma while still holding mmap_sem */
- hold_anon_vma(rmap_item, vma->anon_vma);
+ rmap_item->anon_vma = vma->anon_vma;
+ get_anon_vma(vma->anon_vma);
out:
up_read(&mm->mmap_sem);
return err;
Index: linux-2.6/mm/migrate.c
===================================================================
--- linux-2.6.orig/mm/migrate.c
+++ linux-2.6/mm/migrate.c
@@ -764,7 +764,7 @@ static int unmap_and_move(new_page_t get
/* Drop an anon_vma reference if we took one */
if (anon_vma)
- drop_anon_vma(anon_vma);
+ put_anon_vma(anon_vma);
uncharge:
if (!charge)
@@ -857,7 +857,7 @@ static int unmap_and_move_huge_page(new_
remove_migration_ptes(hpage, hpage);
if (anon_vma)
- drop_anon_vma(anon_vma);
+ put_anon_vma(anon_vma);
out:
unlock_page(hpage);
Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c
+++ linux-2.6/mm/rmap.c
@@ -278,7 +278,7 @@ static void anon_vma_unlink(struct anon_
if (empty) {
/* We no longer need the root anon_vma */
if (anon_vma->root != anon_vma)
- drop_anon_vma(anon_vma->root);
+ put_anon_vma(anon_vma->root);
anon_vma_free(anon_vma);
}
}
@@ -1489,7 +1489,7 @@ int try_to_munlock(struct page *page)
* we know we are the last user, nobody else can get a reference and we
* can do the freeing without the lock.
*/
-void drop_anon_vma(struct anon_vma *anon_vma)
+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)) {
On 02/17/2011 11:19 AM, Peter Zijlstra wrote:
Reviewed-by: Rik van Riel <[email protected]>
On Thu, Feb 17, 2011 at 05:19:49PM +0100, Peter Zijlstra wrote:
> The normal code pattern used in the kernel is: get/put.
>
> Reviewed-by: KAMEZAWA Hiroyuki <[email protected]>
> Acked-by: Hugh Dickins <[email protected]>
> Signed-off-by: Peter Zijlstra <[email protected]>
Acked-by: Mel Gorman <[email protected]>
--
Mel Gorman
SUSE Labs