1 files changed, 76 insertions, 25 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 71a58f67f48..74a8c825ff2 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -35,7 +35,7 @@ struct compact_control {
 	unsigned long migrate_pfn;	/* isolate_migratepages search base */
 	bool sync;			/* Synchronous migration */
 
-	unsigned int order;		/* order a direct compactor needs */
+	int order;			/* order a direct compactor needs */
 	int migratetype;		/* MOVABLE, RECLAIMABLE etc */
 	struct zone *zone;
 };
@@ -313,12 +313,34 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 		} else if (!locked)
 			spin_lock_irq(&zone->lru_lock);
 
+		/*
+		 * migrate_pfn does not necessarily start aligned to a
+		 * pageblock. Ensure that pfn_valid is called when moving
+		 * into a new MAX_ORDER_NR_PAGES range in case of large
+		 * memory holes within the zone
+		 */
+		if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
+			if (!pfn_valid(low_pfn)) {
+				low_pfn += MAX_ORDER_NR_PAGES - 1;
+				continue;
+			}
+		}
+
 		if (!pfn_valid_within(low_pfn))
 			continue;
 		nr_scanned++;
 
-		/* Get the page and skip if free */
+		/*
+		 * Get the page and ensure the page is within the same zone.
+		 * See the comment in isolate_freepages about overlapping
+		 * nodes. It is deliberate that the new zone lock is not taken
+		 * as memory compaction should not move pages between nodes.
+		 */
 		page = pfn_to_page(low_pfn);
+		if (page_zone(page) != zone)
+			continue;
+
+		/* Skip if free */
 		if (PageBuddy(page))
 			continue;
 
@@ -653,49 +675,71 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
 
 
 /* Compact all zones within a node */
-static int compact_node(int nid)
+static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
 {
 	int zoneid;
-	pg_data_t *pgdat;
 	struct zone *zone;
 
-	if (nid < 0 || nid >= nr_node_ids || !node_online(nid))
-		return -EINVAL;
-	pgdat = NODE_DATA(nid);
-
-	/* Flush pending updates to the LRU lists */
-	lru_add_drain_all();
-
 	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
-		struct compact_control cc = {
-			.nr_freepages = 0,
-			.nr_migratepages = 0,
-			.order = -1,
-			.sync = true,
-		};
 
 		zone = &pgdat->node_zones[zoneid];
 		if (!populated_zone(zone))
 			continue;
 
-		cc.zone = zone;
-		INIT_LIST_HEAD(&cc.freepages);
-		INIT_LIST_HEAD(&cc.migratepages);
-
-		compact_zone(zone, &cc);
+		cc->nr_freepages = 0;
+		cc->nr_migratepages = 0;
+		cc->zone = zone;
+		INIT_LIST_HEAD(&cc->freepages);
+		INIT_LIST_HEAD(&cc->migratepages);
+
+		if (cc->order == -1 || !compaction_deferred(zone, cc->order))
+			compact_zone(zone, cc);
+
+		if (cc->order > 0) {
+			int ok = zone_watermark_ok(zone, cc->order,
+						low_wmark_pages(zone), 0, 0);
+			if (ok && cc->order > zone->compact_order_failed)
+				zone->compact_order_failed = cc->order + 1;
+			/* Currently async compaction is never deferred. */
+			else if (!ok && cc->sync)
+				defer_compaction(zone, cc->order);
+		}
 
-		VM_BUG_ON(!list_empty(&cc.freepages));
-		VM_BUG_ON(!list_empty(&cc.migratepages));
+		VM_BUG_ON(!list_empty(&cc->freepages));
+		VM_BUG_ON(!list_empty(&cc->migratepages));
 	}
 
 	return 0;
 }
 
+int compact_pgdat(pg_data_t *pgdat, int order)
+{
+	struct compact_control cc = {
+		.order = order,
+		.sync = false,
+	};
+
+	return __compact_pgdat(pgdat, &cc);
+}
+
+static int compact_node(int nid)
+{
+	struct compact_control cc = {
+		.order = -1,
+		.sync = true,
+	};
+
+	return __compact_pgdat(NODE_DATA(nid), &cc);
+}
+
 /* Compact all nodes in the system */
 static int compact_nodes(void)
 {
 	int nid;
 
+	/* Flush pending updates to the LRU lists */
+	lru_add_drain_all();
+
 	for_each_online_node(nid)
 		compact_node(nid);
 
@@ -728,7 +772,14 @@ ssize_t sysfs_compact_node(struct device *dev,
 			struct device_attribute *attr,
 			const char *buf, size_t count)
 {
-	compact_node(dev->id);
+	int nid = dev->id;
+
+	if (nid >= 0 && nid < nr_node_ids && node_online(nid)) {
+		/* Flush pending updates to the LRU lists */
+		lru_add_drain_all();
+
+		compact_node(nid);
+	}
 
 	return count;
 }