1 files changed, 19 insertions, 1 deletions

diff --git a/mm/mmzone.c b/mm/mmzone.c
index 4596d81b89b1..bce796e8487f 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -1,7 +1,7 @@
 /*
  * linux/mm/mmzone.c
  *
- * management codes for pgdats and zones.
+ * management codes for pgdats, zones and page flags
  */
 
 
@@ -96,3 +96,21 @@ void lruvec_init(struct lruvec *lruvec)
         for_each_lru(lru)
                 INIT_LIST_HEAD(&lruvec->lists[lru]);
 }
+
+#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_NID_NOT_IN_PAGE_FLAGS)
+int page_xchg_last_nid(struct page *page, int nid)
+{
+        unsigned long old_flags, flags;
+        int last_nid;
+
+        do {
+                old_flags = flags = page->flags;
+                last_nid = page_last_nid(page);
+
+                flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT);
+                flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT;
+        } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
+
+        return last_nid;
+}
+#endif