1 files changed, 110 insertions, 28 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b864584c92b4..f7873a47fa8e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -687,16 +687,48 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
 	return 0;
 }
 
+/*
+ * Go through the free lists for the given migratetype and remove
+ * the smallest available page from the freelists
+ */
+static struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
+						int migratetype)
+{
+	unsigned int current_order;
+	struct free_area * area;
+	struct page *page;
+
+	/* Find a page of the appropriate size in the preferred list */
+	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
+		area = &(zone->free_area[current_order]);
+		if (list_empty(&area->free_list[migratetype]))
+			continue;
+
+		page = list_entry(area->free_list[migratetype].next,
+							struct page, lru);
+		list_del(&page->lru);
+		rmv_page_order(page);
+		area->nr_free--;
+		__mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
+		expand(zone, page, order, current_order, area, migratetype);
+		return page;
+	}
+
+	return NULL;
+}
+
+
 #ifdef CONFIG_PAGE_GROUP_BY_MOBILITY
 /*
  * This array describes the order lists are fallen back to when
  * 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_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},
+	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_HIGHATOMIC, MIGRATE_RESERVE },
+	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_HIGHATOMIC, MIGRATE_RESERVE },
+	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_HIGHATOMIC, MIGRATE_RESERVE },
+	[MIGRATE_HIGHATOMIC]  = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_MOVABLE,    MIGRATE_RESERVE },
+	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE,    MIGRATE_RESERVE }, /* Never used */
 };
 
 /*
@@ -799,6 +831,9 @@ retry:
 		for (i = 0; i < MIGRATE_TYPES - 1; i++) {
 			migratetype = fallbacks[start_migratetype][i];
 
+			/* MIGRATE_RESERVE handled later if necessary */
+			if (migratetype == MIGRATE_RESERVE)
+				continue;
 			/*
 			 * Make it hard to fallback to blocks used for
 			 * high-order atomic allocations
@@ -861,7 +896,8 @@ retry:
 		goto retry;
 	}
 
-	return NULL;
+	/* Use MIGRATE_RESERVE rather than fail an allocation */
+	return __rmqueue_smallest(zone, order, MIGRATE_RESERVE);
 }
 #else
 static struct page *__rmqueue_fallback(struct zone *zone, int order,
@@ -871,36 +907,19 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order,
 }
 #endif /* CONFIG_PAGE_GROUP_BY_MOBILITY */
 
-/* 
+/*
  * Do the hard work of removing an element from the buddy allocator.
  * Call me with the zone->lock already held.
  */
 static struct page *__rmqueue(struct zone *zone, unsigned int order,
 						int migratetype)
 {
-	struct free_area * area;
-	unsigned int current_order;
 	struct page *page;
 
-	/* Find a page of the appropriate size in the preferred list */
-	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
-		area = &(zone->free_area[current_order]);
-		if (list_empty(&area->free_list[migratetype]))
-			continue;
-
-		page = list_entry(area->free_list[migratetype].next,
-							struct page, lru);
-		list_del(&page->lru);
-		rmv_page_order(page);
-		area->nr_free--;
-		__mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
-		expand(zone, page, order, current_order, area, migratetype);
-		goto got_page;
-	}
-
-	page = __rmqueue_fallback(zone, order, migratetype);
+	page = __rmqueue_smallest(zone, order, migratetype);
 
-got_page:
+	if (unlikely(!page))
+		page = __rmqueue_fallback(zone, order, migratetype);
 
 	return page;
 }
@@ -2506,6 +2525,65 @@ static inline unsigned long wait_table_bits(unsigned long size)
 
 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
 
+#ifdef CONFIG_PAGE_GROUP_BY_MOBILITY
+/*
+ * Mark a number of MAX_ORDER_NR_PAGES blocks as MIGRATE_RESERVE. The number
+ * of blocks reserved is based on zone->pages_min. The memory within the
+ * reserve will tend to store contiguous free pages. Setting min_free_kbytes
+ * higher will lead to a bigger reserve which will get freed as contiguous
+ * blocks as reclaim kicks in
+ */
+static void setup_zone_migrate_reserve(struct zone *zone)
+{
+	unsigned long start_pfn, pfn, end_pfn;
+	struct page *page;
+	unsigned long reserve, block_migratetype;
+
+	/* Get the start pfn, end pfn and the number of blocks to reserve */
+	start_pfn = zone->zone_start_pfn;
+	end_pfn = start_pfn + zone->spanned_pages;
+	reserve = roundup(zone->pages_min, MAX_ORDER_NR_PAGES) >> (MAX_ORDER-1);
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += MAX_ORDER_NR_PAGES) {
+		if (!pfn_valid(pfn))
+			continue;
+		page = pfn_to_page(pfn);
+
+		/* Blocks with reserved pages will never free, skip them. */
+		if (PageReserved(page))
+			continue;
+
+		block_migratetype = get_pageblock_migratetype(page);
+
+		/* If this block is reserved, account for it */
+		if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
+			reserve--;
+			continue;
+		}
+
+		/* Suitable for reserving if this block is movable */
+		if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
+			set_pageblock_migratetype(page, MIGRATE_RESERVE);
+			move_freepages_block(zone, page, MIGRATE_RESERVE);
+			reserve--;
+			continue;
+		}
+
+		/*
+		 * If the reserve is met and this is a previous reserved block,
+		 * take it back
+		 */
+		if (block_migratetype == MIGRATE_RESERVE) {
+			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+			move_freepages_block(zone, page, MIGRATE_MOVABLE);
+		}
+	}
+}
+#else
+static inline void setup_zone_migrate_reserve(struct zone *zone)
+{
+}
+#endif /* CONFIG_PAGE_GROUP_BY_MOBILITY */
 /*
  * Initially all pages are reserved - free ones are freed
  * up by free_all_bootmem() once the early boot process is
@@ -2541,9 +2619,12 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 		 * movable at startup. This will force kernel allocations
 		 * to reserve their blocks rather than leaking throughout
 		 * the address space during boot when many long-lived
-		 * kernel allocations are made
+		 * kernel allocations are made. Later some blocks near
+		 * the start are marked MIGRATE_RESERVE by
+		 * setup_zone_migrate_reserve()
 		 */
-		set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+		if ((pfn & (MAX_ORDER_NR_PAGES-1)))
+			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
 
 		INIT_LIST_HEAD(&page->lru);
 #ifdef WANT_PAGE_VIRTUAL
@@ -4078,6 +4159,7 @@ void setup_per_zone_pages_min(void)
 
 		zone->pages_low   = zone->pages_min + (tmp >> 2);
 		zone->pages_high  = zone->pages_min + (tmp >> 1);
+		setup_zone_migrate_reserve(zone);
 		spin_unlock_irqrestore(&zone->lru_lock, flags);
 	}