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>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 932a8aac6f76344280b331f7ae1fe0e013653a28..bcaab4e6fe913ac6e3f2ef0a6c83ea24d8972867 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -241,13 +241,13 @@ struct inode;
 /* It's valid only if the page is free path or free_list */
 static inline void set_freepage_migratetype(struct page *page, int migratetype)
 {
-       set_page_private(page, migratetype);
+       page->index = migratetype;
 }
 
 /* It's valid only if the page is free path or free_list */
 static inline int get_freepage_migratetype(struct page *page)
 {
-       return page_private(page);
+       return page->index;
 }
 
 /*

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d27209a31d32fbe58f3a5e5b54322b73f2bd54c3..cd2bfddccbc47acd43455c24b581207e0f4d4919 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -728,6 +728,7 @@ 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;
@@ -736,8 +737,9 @@ 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);
 }
 
@@ -958,6 +960,7 @@ 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;
        }