mm: check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE

[pandora-kernel.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 44019da..01e6b61 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3328,6 +3328,20 @@ 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
@@ -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);