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authorKonstantin Khlebnikov <khlebnikov@openvz.org>2011-12-08 14:33:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-12-09 07:50:27 -0800
commit83aeeada7c69f35e5100b27ec354335597a7a488 (patch)
tree44644e68f303368feba7c8ba3e0e0991d6238ada
parent635697c663f38106063d5659f0cf2e45afcd4bb5 (diff)
downloadlinux-stericsson-83aeeada7c69f35e5100b27ec354335597a7a488.tar.gz
vmscan: use atomic-long for shrinker batching
Use atomic-long operations instead of looping around cmpxchg(). [akpm@linux-foundation.org: massage atomic.h inclusions] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/fs.h2
-rw-r--r--include/linux/mm.h1
-rw-r--r--include/linux/shrinker.h2
-rw-r--r--mm/vmscan.c17
4 files changed, 10 insertions, 12 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 019dc558df1a..e0bc4ffb8e7f 100644
--- a/include/linux/fs.h
+++ b/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/include/linux/mm.h b/include/linux/mm.h
index 3dc3a8c2c485..4baadd18f4ad 100644
--- a/include/linux/mm.h
+++ b/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/include/linux/shrinker.h b/include/linux/shrinker.h
index a83833a1f7a2..07ceb97d53fa 100644
--- a/include/linux/shrinker.h
+++ b/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/mm/vmscan.c b/mm/vmscan.c
index f5255442ae2b..f54a05b7a61d 100644
--- a/mm/vmscan.c
+++ b/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);
}