mm/page_alloc: fix freeing of MIGRATE_RESERVE migratetype pages

Pages allocated from MIGRATE_RESERVE migratetype pageblocks
are not freed back to MIGRATE_RESERVE migratetype free
lists in free_pcppages_bulk()->__free_one_page() if we got
to free_pcppages_bulk() through drain_[zone_]pages().
The freeing through free_hot_cold_page() is okay because
freepage migratetype is set to pageblock migratetype before
calling free_pcppages_bulk().  If pages of MIGRATE_RESERVE
migratetype end up on the free lists of other migratetype
whole Reserved pageblock may be later changed to the other
migratetype in __rmqueue_fallback() and it will be never
changed back to be a Reserved pageblock.  Fix the issue by
preserving freepage migratetype as a pageblock migratetype
(instead of overriding it to the requested migratetype)
for MIGRATE_RESERVE migratetype pages in rmqueue_bulk().

The problem was introduced in v2.6.31 by commit ed0ae21
("page allocator: do not call get_pageblock_migratetype()
more than necessary").

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reported-by: Yong-Taek Lee <ytk.lee@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: I1d4ab2a3241387160dd376b0ead864cd2b0c59f0

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 5c76737..dc40e42 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -63,6 +63,11 @@ enum {
        MIGRATE_TYPES
 };
 
+static inline bool is_migrate_reserve(int migratetype)
+{
+       return unlikely(migratetype == MIGRATE_RESERVE);
+}
+
 #ifdef CONFIG_CMA
 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
 #else

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8855d81..e18eb70 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1140,7 +1140,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
                        unsigned long count, struct list_head *list,
                        int migratetype, int cold)
 {
-       int mt = migratetype, i;
+       int mt, i;
 
        spin_lock(&zone->lock);
        for (i = 0; i < count; ++i) {
@@ -1161,9 +1161,13 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
                        list_add(&page->lru, list);
                else
                        list_add_tail(&page->lru, list);
+               mt = get_pageblock_migratetype(page);
                if (IS_ENABLED(CONFIG_CMA)) {
-                       mt = get_pageblock_migratetype(page);
-                       if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
+                       if (!is_migrate_cma(mt) && !is_migrate_isolate(mt) &&
+                           !is_migrate_reserve(mt))
+                               mt = migratetype;
+               } else {
+                       if (!is_migrate_reserve(mt))
                                mt = migratetype;
                }
                set_freepage_migratetype(page, mt);