1 files changed, 17 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 44019da9632e..01e6b614839d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3329,6 +3329,20 @@ static inline unsigned long wait_table_bits(unsigned long size)
 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
 
 /*
+ * Check if a pageblock contains reserved pages
+ */
+static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
+{
+        unsigned long pfn;
+
+        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+                if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
+                        return 1;
+        }
+        return 0;
+}
+
+/*
  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
  * of blocks reserved is based on min_wmark_pages(zone). The memory within
  * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
@@ -3337,7 +3351,7 @@ static inline unsigned long wait_table_bits(unsigned long size)
  */
 static void setup_zone_migrate_reserve(struct zone *zone)
 {
-        unsigned long start_pfn, pfn, end_pfn;
+        unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
         struct page *page;
         unsigned long block_migratetype;
         int reserve;
@@ -3367,7 +3381,8 @@ static void setup_zone_migrate_reserve(struct zone *zone)
                         continue;
 
                 /* Blocks with reserved pages will never free, skip them. */
-                if (PageReserved(page))
+                block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
+                if (pageblock_is_reserved(pfn, block_end_pfn))
                         continue;
 
                 block_migratetype = get_pageblock_migratetype(page);