1 files changed, 45 insertions, 36 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5db32fdfaf39..1838c15ca4fd 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -443,6 +443,10 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
 		BUG_ON(PageActive(page));
 
 		sc->nr_scanned++;
+
+		if (!sc->may_swap && page_mapped(page))
+			goto keep_locked;
+
 		/* Double the slab pressure for mapped and swapcache pages */
 		if (page_mapped(page) || PageSwapCache(page))
 			sc->nr_scanned++;
@@ -1191,9 +1195,47 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
 	struct page *page;
 	struct pagevec pvec;
 	int reclaim_mapped = 0;
-	long mapped_ratio;
-	long distress;
-	long swap_tendency;
+
+	if (unlikely(sc->may_swap)) {
+		long mapped_ratio;
+		long distress;
+		long swap_tendency;
+
+		/*
+		 * `distress' is a measure of how much trouble we're having
+		 * reclaiming pages.  0 -> no problems.  100 -> great trouble.
+		 */
+		distress = 100 >> zone->prev_priority;
+
+		/*
+		 * The point of this algorithm is to decide when to start
+		 * reclaiming mapped memory instead of just pagecache.  Work out
+		 * how much memory
+		 * is mapped.
+		 */
+		mapped_ratio = (sc->nr_mapped * 100) / total_memory;
+
+		/*
+		 * Now decide how much we really want to unmap some pages.  The
+		 * mapped ratio is downgraded - just because there's a lot of
+		 * mapped memory doesn't necessarily mean that page reclaim
+		 * isn't succeeding.
+		 *
+		 * The distress ratio is important - we don't want to start
+		 * going oom.
+		 *
+		 * A 100% value of vm_swappiness overrides this algorithm
+		 * altogether.
+		 */
+		swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
+
+		/*
+		 * Now use this metric to decide whether to start moving mapped
+		 * memory onto the inactive list.
+		 */
+		if (swap_tendency >= 100)
+			reclaim_mapped = 1;
+	}
 
 	lru_add_drain();
 	spin_lock_irq(&zone->lru_lock);
@@ -1203,37 +1245,6 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
 	zone->nr_active -= pgmoved;
 	spin_unlock_irq(&zone->lru_lock);
 
-	/*
-	 * `distress' is a measure of how much trouble we're having reclaiming
-	 * pages.  0 -> no problems.  100 -> great trouble.
-	 */
-	distress = 100 >> zone->prev_priority;
-
-	/*
-	 * The point of this algorithm is to decide when to start reclaiming
-	 * mapped memory instead of just pagecache.  Work out how much memory
-	 * is mapped.
-	 */
-	mapped_ratio = (sc->nr_mapped * 100) / total_memory;
-
-	/*
-	 * Now decide how much we really want to unmap some pages.  The mapped
-	 * ratio is downgraded - just because there's a lot of mapped memory
-	 * doesn't necessarily mean that page reclaim isn't succeeding.
-	 *
-	 * The distress ratio is important - we don't want to start going oom.
-	 *
-	 * A 100% value of vm_swappiness overrides this algorithm altogether.
-	 */
-	swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
-
-	/*
-	 * Now use this metric to decide whether to start moving mapped memory
-	 * onto the inactive list.
-	 */
-	if (swap_tendency >= 100)
-		reclaim_mapped = 1;
-
 	while (!list_empty(&l_hold)) {
 		cond_resched();
 		page = lru_to_page(&l_hold);
@@ -1610,9 +1621,7 @@ scan:
 			sc.nr_reclaimed = 0;
 			sc.priority = priority;
 			sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
-			atomic_inc(&zone->reclaim_in_progress);
 			shrink_zone(zone, &sc);
-			atomic_dec(&zone->reclaim_in_progress);
 			reclaim_state->reclaimed_slab = 0;
 			nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
 						lru_pages);