3 files changed, 51 insertions, 18 deletions

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index bb2bbdbe5464..7a9323aef4a3 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -23,6 +23,7 @@ extern int fragmentation_index(struct zone *zone, unsigned int order);
 extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
                         int order, gfp_t gfp_mask, nodemask_t *mask,
                         bool sync);
+extern int compact_pgdat(pg_data_t *pgdat, int order);
 extern unsigned long compaction_suitable(struct zone *zone, int order);
 
 /* Do not skip compaction more than 64 times */
@@ -62,6 +63,11 @@ static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
         return COMPACT_CONTINUE;
 }
 
+static inline int compact_pgdat(pg_data_t *pgdat, int order)
+{
+        return COMPACT_CONTINUE;
+}
+
 static inline unsigned long compaction_suitable(struct zone *zone, int order)
 {
         return COMPACT_SKIPPED;
diff --git a/mm/compaction.c b/mm/compaction.c
index d9ebebe1a2aa..36f0f61f4a24 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -675,44 +675,61 @@ 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);
+                cc->nr_freepages = 0;
+                cc->nr_migratepages = 0;
+                cc->zone = zone;
+                INIT_LIST_HEAD(&cc->freepages);
+                INIT_LIST_HEAD(&cc->migratepages);
 
-                compact_zone(zone, &cc);
+                if (cc->order < 0 || !compaction_deferred(zone))
+                        compact_zone(zone, cc);
 
-                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)
+{
+        pg_data_t *pgdat;
+        struct compact_control cc = {
+                .order = -1,
+                .sync = true,
+        };
+
+        if (nid < 0 || nid >= nr_node_ids || !node_online(nid))
+                return -EINVAL;
+        pgdat = NODE_DATA(nid);
+
+        return __compact_pgdat(pgdat, &cc);
+}
+
 /* Compact all nodes in the system */
 static int compact_nodes(void)
 {
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d7dad2a4e69c..b2b4c4a0ada2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2919,6 +2919,8 @@ out:
          * and it is potentially going to sleep here.
          */
         if (order) {
+                int zones_need_compaction = 1;
+
                 for (i = 0; i <= end_zone; i++) {
                         struct zone *zone = pgdat->node_zones + i;
 
@@ -2939,9 +2941,17 @@ out:
                                 goto loop_again;
                         }
 
+                        /* Check if the memory needs to be defragmented. */
+                        if (zone_watermark_ok(zone, order,
+                                    low_wmark_pages(zone), *classzone_idx, 0))
+                                zones_need_compaction = 0;
+
                         /* If balanced, clear the congested flag */
                         zone_clear_flag(zone, ZONE_CONGESTED);
                 }
+
+                if (zones_need_compaction)
+                        compact_pgdat(pgdat, order);
         }
 
         /*