2 files changed, 33 insertions, 7 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4721e9aa3ced..a8140a9a65e8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -37,11 +37,13 @@
 #define MIGRATE_UNMOVABLE     0
 #define MIGRATE_RECLAIMABLE   1
 #define MIGRATE_MOVABLE       2
-#define MIGRATE_TYPES         3
+#define MIGRATE_HIGHATOMIC    3
+#define MIGRATE_TYPES         4
 #else
 #define MIGRATE_UNMOVABLE     0
 #define MIGRATE_UNRECLAIMABLE 0
 #define MIGRATE_MOVABLE       0
+#define MIGRATE_HIGHATOMIC    0
 #define MIGRATE_TYPES         1
 #endif
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 29f4de1423c9..03fef8d987f6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -170,10 +170,16 @@ static void set_pageblock_migratetype(struct page *page, int migratetype)
                                         PB_migrate, PB_migrate_end);
 }
 
-static inline int gfpflags_to_migratetype(gfp_t gfp_flags)
+static inline int allocflags_to_migratetype(gfp_t gfp_flags, int order)
 {
         WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
 
+        /* Cluster high-order atomic allocations together */
+        if (unlikely(order > 0) &&
+                        (!(gfp_flags & __GFP_WAIT) || in_interrupt()))
+                return MIGRATE_HIGHATOMIC;
+
+        /* Cluster based on mobility */
         return (((gfp_flags & __GFP_MOVABLE) != 0) << 1) |
                 ((gfp_flags & __GFP_RECLAIMABLE) != 0);
 }
@@ -188,7 +194,7 @@ static void set_pageblock_migratetype(struct page *page, int migratetype)
 {
 }
 
-static inline int gfpflags_to_migratetype(gfp_t gfp_flags)
+static inline int allocflags_to_migratetype(gfp_t gfp_flags, int order)
 {
         return MIGRATE_UNMOVABLE;
 }
@@ -679,9 +685,10 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
  * the free lists for the desirable migrate type are depleted
  */
 static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
-        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE   },
-        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE   },
-        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE },
+        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,  MIGRATE_HIGHATOMIC },
+        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,  MIGRATE_HIGHATOMIC },
+        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE,MIGRATE_HIGHATOMIC },
+        [MIGRATE_HIGHATOMIC]  = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE,MIGRATE_MOVABLE},
 };
 
 /*
@@ -758,13 +765,24 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order,
         int current_order;
         struct page *page;
         int migratetype, i;
+        int nonatomic_fallback_atomic = 0;
 
+retry:
         /* Find the largest possible block of pages in the other list */
         for (current_order = MAX_ORDER-1; current_order >= order;
                                                 --current_order) {
                 for (i = 0; i < MIGRATE_TYPES - 1; i++) {
                         migratetype = fallbacks[start_migratetype][i];
 
+                        /*
+                         * Make it hard to fallback to blocks used for
+                         * high-order atomic allocations
+                         */
+                        if (migratetype == MIGRATE_HIGHATOMIC &&
+                                start_migratetype != MIGRATE_UNMOVABLE &&
+                                !nonatomic_fallback_atomic)
+                                continue;
+
                         area = &(zone->free_area[current_order]);
                         if (list_empty(&area->free_list[migratetype]))
                                 continue;
@@ -797,6 +815,12 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order,
                 }
         }
 
+        /* Allow fallback to high-order atomic blocks if memory is that low */
+        if (!nonatomic_fallback_atomic) {
+                nonatomic_fallback_atomic = 1;
+                goto retry;
+        }
+
         return NULL;
 }
 #else
@@ -1058,7 +1082,7 @@ static struct page *buffered_rmqueue(struct zonelist *zonelist,
         struct page *page;
         int cold = !!(gfp_flags & __GFP_COLD);
         int cpu;
-        int migratetype = gfpflags_to_migratetype(gfp_flags);
+        int migratetype = allocflags_to_migratetype(gfp_flags, order);
 
 again:
         cpu  = get_cpu();