Merge tag 'v3.8-rc6' into next/soc

Linux 3.8-rc6

1 files changed, 13 insertions, 1 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 3b676b0c5c3..c38778610aa 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1679,9 +1679,21 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 	page_xchg_last_nid(new_page, page_last_nid(page));
 
 	isolated = numamigrate_isolate_page(pgdat, page);
-	if (!isolated) {
+
+	/*
+	 * Failing to isolate or a GUP pin prevents migration. The expected
+	 * page count is 2. 1 for anonymous pages without a mapping and 1
+	 * for the callers pin. If the page was isolated, the page will
+	 * need to be put back on the LRU.
+	 */
+	if (!isolated || page_count(page) != 2) {
 		count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR);
 		put_page(new_page);
+		if (isolated) {
+			putback_lru_page(page);
+			isolated = 0;
+			goto out;
+		}
 		goto out_keep_locked;
 	}