---

yaml
---
r: 126261
b: refs/heads/master
c: 73ce02e
h: refs/heads/master
i:
  126259: 9bf9ea0
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 594fe1a044325bb0a1a49ca7d086e3df4f1df59a
+refs/heads/master: 73ce02e96fe34a983199a9855b2ae738f960a6ee

trunk/mm/vmscan.c

@@ -1867,6 +1867,23 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 
 		try_to_freeze();
 
+		/*
+		 * Fragmentation may mean that the system cannot be
+		 * rebalanced for high-order allocations in all zones.
+		 * At this point, if nr_reclaimed < SWAP_CLUSTER_MAX,
+		 * it means the zones have been fully scanned and are still
+		 * not balanced. For high-order allocations, there is
+		 * little point trying all over again as kswapd may
+		 * infinite loop.
+		 *
+		 * Instead, recheck all watermarks at order-0 as they
+		 * are the most important. If watermarks are ok, kswapd will go
+		 * back to sleep. High-order users can still perform direct
+		 * reclaim if they wish.
+		 */
+		if (sc.nr_reclaimed < SWAP_CLUSTER_MAX)
+			order = sc.order = 0;
+
 		goto loop_again;
 	}