---

yaml
---
r: 83775
b: refs/heads/master
c: f1a9ee7
h: refs/heads/master
i:
  83773: a80e0d1
  83771: af6f2c3
  83767: 36763e7
  83759: c3ed69b
  83743: 6083148
  83711: c95b5eb
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fef1bdd68c81b71882ccb6f47c70980a03182063
+refs/heads/master: f1a9ee758de7de1e040de849fdef46e6802ea117

trunk/mm/vmscan.c

@@ -70,6 +70,13 @@ struct scan_control {
 
 	int order;
 
+	/*
+	 * Pages that have (or should have) IO pending.  If we run into
+	 * a lot of these, we're better off waiting a little for IO to
+	 * finish rather than scanning more pages in the VM.
+	 */
+	int nr_io_pages;
+
 	/* Which cgroup do we reclaim from */
 	struct mem_cgroup *mem_cgroup;
 
@@ -499,8 +506,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 			 */
 			if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs)
 				wait_on_page_writeback(page);
-			else
+			else {
+				sc->nr_io_pages++;
 				goto keep_locked;
+			}
 		}
 
 		referenced = page_referenced(page, 1, sc->mem_cgroup);
@@ -539,8 +548,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		if (PageDirty(page)) {
 			if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced)
 				goto keep_locked;
-			if (!may_enter_fs)
+			if (!may_enter_fs) {
+				sc->nr_io_pages++;
 				goto keep_locked;
+			}
 			if (!sc->may_writepage)
 				goto keep_locked;
 
@@ -551,8 +562,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 			case PAGE_ACTIVATE:
 				goto activate_locked;
 			case PAGE_SUCCESS:
-				if (PageWriteback(page) || PageDirty(page))
+				if (PageWriteback(page) || PageDirty(page)) {
+					sc->nr_io_pages++;
 					goto keep;
+				}
 				/*
 				 * A synchronous write - probably a ramdisk.  Go
 				 * ahead and try to reclaim the page.
@@ -1259,6 +1272,7 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
 
 	for (priority = DEF_PRIORITY; priority >= 0; priority--) {
 		sc->nr_scanned = 0;
+		sc->nr_io_pages = 0;
 		if (!priority)
 			disable_swap_token();
 		nr_reclaimed += shrink_zones(priority, zones, sc);
@@ -1292,7 +1306,8 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
 		}
 
 		/* Take a nap, wait for some writeback to complete */
-		if (sc->nr_scanned && priority < DEF_PRIORITY - 2)
+		if (sc->nr_scanned && priority < DEF_PRIORITY - 2 &&
+				sc->nr_io_pages > sc->swap_cluster_max)
 			congestion_wait(WRITE, HZ/10);
 	}
 	/* top priority shrink_caches still had more to do? don't OOM, then */
@@ -1424,6 +1439,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 		if (!priority)
 			disable_swap_token();
 
+		sc.nr_io_pages = 0;
 		all_zones_ok = 1;
 
 		/*
@@ -1516,7 +1532,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 		 * OK, kswapd is getting into trouble.  Take a nap, then take
 		 * another pass across the zones.
 		 */
-		if (total_scanned && priority < DEF_PRIORITY - 2)
+		if (total_scanned && priority < DEF_PRIORITY - 2 &&
+					sc.nr_io_pages > sc.swap_cluster_max)
 			congestion_wait(WRITE, HZ/10);
 
 		/*