1 files changed, 40 insertions, 20 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2cff0d4..4d4e859 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -205,19 +205,24 @@ static inline int do_shrinker_shrink(struct shrinker *shrinker,
  *
  * Returns the number of slab objects which we shrunk.
  */
-unsigned long shrink_slab(struct shrink_control *shrink,
+unsigned long shrink_slab(struct shrink_control *shrinkctl,
 			  unsigned long nr_pages_scanned,
 			  unsigned long lru_pages)
 {
 	struct shrinker *shrinker;
-	unsigned long ret = 0;
+	unsigned long freed = 0;
 
 	if (nr_pages_scanned == 0)
 		nr_pages_scanned = SWAP_CLUSTER_MAX;
 
 	if (!down_read_trylock(&shrinker_rwsem)) {
-		/* Assume we'll be able to shrink next time */
-		ret = 1;
+		/*
+		 * If we would return 0, our callers would understand that we
+		 * have nothing else to shrink and give up trying. By returning
+		 * 1 we keep it going and assume we'll be able to shrink next
+		 * time.
+		 */
+		freed = 1;
 		goto out;
 	}
 
@@ -225,14 +230,16 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		unsigned long long delta;
 		long total_scan;
 		long max_pass;
-		int shrink_ret = 0;
 		long nr;
 		long new_nr;
 		long batch_size = shrinker->batch ? shrinker->batch
 						  : SHRINK_BATCH;
 
-		max_pass = do_shrinker_shrink(shrinker, shrink, 0);
-		if (max_pass <= 0)
+		if (shrinker->count_objects)
+			max_pass = shrinker->count_objects(shrinker, shrinkctl);
+		else
+			max_pass = do_shrinker_shrink(shrinker, shrinkctl, 0);
+		if (max_pass == 0)
 			continue;
 
 		/*
@@ -248,8 +255,8 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		do_div(delta, lru_pages + 1);
 		total_scan += delta;
 		if (total_scan < 0) {
-			printk(KERN_ERR "shrink_slab: %pF negative objects to "
-			       "delete nr=%ld\n",
+			printk(KERN_ERR
+			"shrink_slab: %pF negative objects to delete nr=%ld\n",
 			       shrinker->shrink, total_scan);
 			total_scan = max_pass;
 		}
@@ -277,20 +284,33 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		if (total_scan > max_pass * 2)
 			total_scan = max_pass * 2;
 
-		trace_mm_shrink_slab_start(shrinker, shrink, nr,
+		trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
 					nr_pages_scanned, lru_pages,
 					max_pass, delta, total_scan);
 
 		while (total_scan >= batch_size) {
-			int nr_before;
 
-			nr_before = do_shrinker_shrink(shrinker, shrink, 0);
-			shrink_ret = do_shrinker_shrink(shrinker, shrink,
-							batch_size);
-			if (shrink_ret == -1)
-				break;
-			if (shrink_ret < nr_before)
-				ret += nr_before - shrink_ret;
+			if (shrinker->scan_objects) {
+				unsigned long ret;
+				shrinkctl->nr_to_scan = batch_size;
+				ret = shrinker->scan_objects(shrinker, shrinkctl);
+
+				if (ret == SHRINK_STOP)
+					break;
+				freed += ret;
+			} else {
+				int nr_before;
+				long ret;
+
+				nr_before = do_shrinker_shrink(shrinker, shrinkctl, 0);
+				ret = do_shrinker_shrink(shrinker, shrinkctl,
+								batch_size);
+				if (ret == -1)
+					break;
+				if (ret < nr_before)
+					freed += nr_before - ret;
+			}
+
 			count_vm_events(SLABS_SCANNED, batch_size);
 			total_scan -= batch_size;
 
@@ -308,12 +328,12 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		else
 			new_nr = atomic_long_read(&shrinker->nr_in_batch);
 
-		trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr);
+		trace_mm_shrink_slab_end(shrinker, freed, nr, new_nr);
 	}
 	up_read(&shrinker_rwsem);
 out:
 	cond_resched();
-	return ret;
+	return freed;
 }
 
 static inline int is_page_cache_freeable(struct page *page)