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authorIngo Molnar <mingo@kernel.org>2012-12-02 19:56:46 +0000
committerMel Gorman <mgorman@suse.de>2012-12-11 14:43:00 +0000
commit5a505085f043e8380f83610f79642853c051e2f1 (patch)
treec9e86ee196b1ef87350ee9b268a515e2eae4d307 /include/linux/rmap.h
parentd28d433512f4f387e2563c14db45a7bb8a338b1a (diff)
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
Convert the struct anon_vma::mutex to an rwsem, which will help in solving a page-migration scalability problem. (Addressed in a separate patch.) The conversion is simple and straightforward: in every case where we mutex_lock()ed we'll now down_write(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
Diffstat (limited to 'include/linux/rmap.h')
-rw-r--r--include/linux/rmap.h16
1 files changed, 8 insertions, 8 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index bfe1f4780644..f3f41d242e25 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -7,7 +7,7 @@
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/mm.h>
-#include <linux/mutex.h>
+#include <linux/rwsem.h>
#include <linux/memcontrol.h>
/*
@@ -25,8 +25,8 @@
* pointing to this anon_vma once its vma list is empty.
*/
struct anon_vma {
- struct anon_vma *root; /* Root of this anon_vma tree */
- struct mutex mutex; /* Serialize access to vma list */
+ struct anon_vma *root; /* Root of this anon_vma tree */
+ struct rw_semaphore rwsem; /* W: modification, R: walking the list */
/*
* The refcount is taken on an anon_vma when there is no
* guarantee that the vma of page tables will exist for
@@ -64,7 +64,7 @@ struct anon_vma_chain {
struct vm_area_struct *vma;
struct anon_vma *anon_vma;
struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
- struct rb_node rb; /* locked by anon_vma->mutex */
+ struct rb_node rb; /* locked by anon_vma->rwsem */
unsigned long rb_subtree_last;
#ifdef CONFIG_DEBUG_VM_RB
unsigned long cached_vma_start, cached_vma_last;
@@ -108,24 +108,24 @@ static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
{
struct anon_vma *anon_vma = vma->anon_vma;
if (anon_vma)
- mutex_lock(&anon_vma->root->mutex);
+ down_write(&anon_vma->root->rwsem);
}
static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
{
struct anon_vma *anon_vma = vma->anon_vma;
if (anon_vma)
- mutex_unlock(&anon_vma->root->mutex);
+ up_write(&anon_vma->root->rwsem);
}
static inline void anon_vma_lock(struct anon_vma *anon_vma)
{
- mutex_lock(&anon_vma->root->mutex);
+ down_write(&anon_vma->root->rwsem);
}
static inline void anon_vma_unlock(struct anon_vma *anon_vma)
{
- mutex_unlock(&anon_vma->root->mutex);
+ up_write(&anon_vma->root->rwsem);
}
/*