---

yaml
---
r: 176269
b: refs/heads/master
c: bb3ab59
h: refs/heads/master
i:
  176267: a76cb5f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f50de2d3811081957156b5d736778799379c29de
+refs/heads/master: bb3ab596832b920c703d1aea1ce76d69c0f71fb7

trunk/include/linux/vmstat.h

@@ -40,7 +40,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		PGSCAN_ZONE_RECLAIM_FAILED,
 #endif
 		PGINODESTEAL, SLABS_SCANNED, KSWAPD_STEAL, KSWAPD_INODESTEAL,
-		KSWAPD_PREMATURE_FAST, KSWAPD_PREMATURE_SLOW,
+		KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
+		KSWAPD_SKIP_CONGESTION_WAIT,
 		PAGEOUTRUN, ALLOCSTALL, PGROTATED,
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,

trunk/mm/vmscan.c

@@ -1905,19 +1905,25 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 #endif
 
 /* is kswapd sleeping prematurely? */
-static int sleeping_prematurely(int order, long remaining)
+static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
 {
-	struct zone *zone;
+	int i;
 
 	/* If a direct reclaimer woke kswapd within HZ/10, it's premature */
 	if (remaining)
 		return 1;
 
 	/* If after HZ/10, a zone is below the high mark, it's premature */
-	for_each_populated_zone(zone)
+	for (i = 0; i < pgdat->nr_zones; i++) {
+		struct zone *zone = pgdat->node_zones + i;
+
+		if (!populated_zone(zone))
+			continue;
+
 		if (!zone_watermark_ok(zone, order, high_wmark_pages(zone),
 								0, 0))
 			return 1;
+	}
 
 	return 0;
 }
@@ -1979,6 +1985,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 	for (priority = DEF_PRIORITY; priority >= 0; priority--) {
 		int end_zone = 0;	/* Inclusive.  0 = ZONE_DMA */
 		unsigned long lru_pages = 0;
+		int has_under_min_watermark_zone = 0;
 
 		/* The swap token gets in the way of swapout... */
 		if (!priority)
@@ -2085,15 +2092,28 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 			if (total_scanned > SWAP_CLUSTER_MAX * 2 &&
 			    total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
 				sc.may_writepage = 1;
+
+			/*
+			 * We are still under min water mark. it mean we have
+			 * GFP_ATOMIC allocation failure risk. Hurry up!
+			 */
+			if (!zone_watermark_ok(zone, order, min_wmark_pages(zone),
+					      end_zone, 0))
+				has_under_min_watermark_zone = 1;
+
 		}
 		if (all_zones_ok)
 			break;		/* kswapd: all done */
 		/*
 		 * OK, kswapd is getting into trouble.  Take a nap, then take
 		 * another pass across the zones.
 		 */
-		if (total_scanned && priority < DEF_PRIORITY - 2)
-			congestion_wait(BLK_RW_ASYNC, HZ/10);
+		if (total_scanned && (priority < DEF_PRIORITY - 2)) {
+			if (has_under_min_watermark_zone)
+				count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT);
+			else
+				congestion_wait(BLK_RW_ASYNC, HZ/10);
+		}
 
 		/*
 		 * We do this so kswapd doesn't build up large priorities for
@@ -2207,7 +2227,7 @@ static int kswapd(void *p)
 				long remaining = 0;
 
 				/* Try to sleep for a short interval */
-				if (!sleeping_prematurely(order, remaining)) {
+				if (!sleeping_prematurely(pgdat, order, remaining)) {
 					remaining = schedule_timeout(HZ/10);
 					finish_wait(&pgdat->kswapd_wait, &wait);
 					prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
@@ -2218,13 +2238,13 @@ static int kswapd(void *p)
 				 * premature sleep. If not, then go fully
 				 * to sleep until explicitly woken up
 				 */
-				if (!sleeping_prematurely(order, remaining))
+				if (!sleeping_prematurely(pgdat, order, remaining))
 					schedule();
 				else {
 					if (remaining)
-						count_vm_event(KSWAPD_PREMATURE_FAST);
+						count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY);
 					else
-						count_vm_event(KSWAPD_PREMATURE_SLOW);
+						count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY);
 				}
 			}
 

trunk/mm/vmstat.c

@@ -683,8 +683,9 @@ static const char * const vmstat_text[] = {
 	"slabs_scanned",
 	"kswapd_steal",
 	"kswapd_inodesteal",
-	"kswapd_slept_prematurely_fast",
-	"kswapd_slept_prematurely_slow",
+	"kswapd_low_wmark_hit_quickly",
+	"kswapd_high_wmark_hit_quickly",
+	"kswapd_skip_congestion_wait",
 	"pageoutrun",
 	"allocstall",