From 42c6bfe2496e5191f4f4b8ab6eb4124523c3becb Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@openvz.org>
Date: Thu, 8 Dec 2011 14:33:54 -0800
Subject: [PATCH] --- yaml --- r: 276533 b: refs/heads/master c:
 83aeeada7c69f35e5100b27ec354335597a7a488 h: refs/heads/master i:   276531:
 8c3c06490f0f8df62b3503d2ebc30addaeaa3d19 v: v3

---
 [refs]                         |  2 +-
 trunk/include/linux/fs.h       |  2 +-
 trunk/include/linux/mm.h       |  1 +
 trunk/include/linux/shrinker.h |  2 +-
 trunk/mm/vmscan.c              | 17 +++++++----------
 5 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/[refs] b/[refs]
index 5108ef06cd7d..dd61eca4e200 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 635697c663f38106063d5659f0cf2e45afcd4bb5
+refs/heads/master: 83aeeada7c69f35e5100b27ec354335597a7a488
diff --git a/trunk/include/linux/fs.h b/trunk/include/linux/fs.h
index 019dc558df1a..e0bc4ffb8e7f 100644
--- a/trunk/include/linux/fs.h
+++ b/trunk/include/linux/fs.h
@@ -393,8 +393,8 @@ struct inodes_stat_t {
 #include <linux/semaphore.h>
 #include <linux/fiemap.h>
 #include <linux/rculist_bl.h>
-#include <linux/shrinker.h>
 #include <linux/atomic.h>
+#include <linux/shrinker.h>
 
 #include <asm/byteorder.h>
 
diff --git a/trunk/include/linux/mm.h b/trunk/include/linux/mm.h
index 3dc3a8c2c485..4baadd18f4ad 100644
--- a/trunk/include/linux/mm.h
+++ b/trunk/include/linux/mm.h
@@ -10,6 +10,7 @@
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
 #include <linux/prio_tree.h>
+#include <linux/atomic.h>
 #include <linux/debug_locks.h>
 #include <linux/mm_types.h>
 #include <linux/range.h>
diff --git a/trunk/include/linux/shrinker.h b/trunk/include/linux/shrinker.h
index a83833a1f7a2..07ceb97d53fa 100644
--- a/trunk/include/linux/shrinker.h
+++ b/trunk/include/linux/shrinker.h
@@ -35,7 +35,7 @@ struct shrinker {
 
 	/* These are for internal use */
 	struct list_head list;
-	long nr;	/* objs pending delete */
+	atomic_long_t nr_in_batch; /* objs pending delete */
 };
 #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
 extern void register_shrinker(struct shrinker *);
diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
index f5255442ae2b..f54a05b7a61d 100644
--- a/trunk/mm/vmscan.c
+++ b/trunk/mm/vmscan.c
@@ -183,7 +183,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone,
  */
 void register_shrinker(struct shrinker *shrinker)
 {
-	shrinker->nr = 0;
+	atomic_long_set(&shrinker->nr_in_batch, 0);
 	down_write(&shrinker_rwsem);
 	list_add_tail(&shrinker->list, &shrinker_list);
 	up_write(&shrinker_rwsem);
@@ -264,9 +264,7 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		 * and zero it so that other concurrent shrinker invocations
 		 * don't also do this scanning work.
 		 */
-		do {
-			nr = shrinker->nr;
-		} while (cmpxchg(&shrinker->nr, nr, 0) != nr);
+		nr = atomic_long_xchg(&shrinker->nr_in_batch, 0);
 
 		total_scan = nr;
 		delta = (4 * nr_pages_scanned) / shrinker->seeks;
@@ -328,12 +326,11 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		 * manner that handles concurrent updates. If we exhausted the
 		 * scan, there is no need to do an update.
 		 */
-		do {
-			nr = shrinker->nr;
-			new_nr = total_scan + nr;
-			if (total_scan <= 0)
-				break;
-		} while (cmpxchg(&shrinker->nr, nr, new_nr) != nr);
+		if (total_scan > 0)
+			new_nr = atomic_long_add_return(total_scan,
+					&shrinker->nr_in_batch);
+		else
+			new_nr = atomic_long_read(&shrinker->nr_in_batch);
 
 		trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr);
 	}