mm: remain migratetype in freed page

The page allocator caches the pageblock information in page->private while
it is in the PCP freelists but this is overwritten with the order of the
page when freed to the buddy allocator.  This patch stores the migratetype
of the page in the page->index field so that it is available at all times
when the page remain in free_list.

This patch adds a new call site in __free_pages_ok so it might be overhead
a bit but it's for high order allocation.  So I believe damage isn't hurt.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6aa0a8e89c5d..94fd283dde98 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -729,6 +729,7 @@ static void __free_pages_ok(struct page *page, unsigned int order)
 {
         unsigned long flags;
         int wasMlocked = __TestClearPageMlocked(page);
+        int migratetype;
 
         if (!free_pages_prepare(page, order))
                 return;
@@ -737,8 +738,9 @@ static void __free_pages_ok(struct page *page, unsigned int order)
         if (unlikely(wasMlocked))
                 free_page_mlock(page);
         __count_vm_events(PGFREE, 1 << order);
-        free_one_page(page_zone(page), page, order,
-                                        get_pageblock_migratetype(page));
+        migratetype = get_pageblock_migratetype(page);
+        set_freepage_migratetype(page, migratetype);
+        free_one_page(page_zone(page), page, order, migratetype);
         local_irq_restore(flags);
 }
 
@@ -959,6 +961,7 @@ static int move_freepages(struct zone *zone,
                 order = page_order(page);
                 list_move(&page->lru,
                           &zone->free_area[order].free_list[migratetype]);
+                set_freepage_migratetype(page, migratetype);
                 page += 1 << order;
                 pages_moved += 1 << order;
         }