diff --git a/mm/migrate.c b/mm/migrate.c
index f9e16350d09c..626ca3c5d07b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1125,7 +1125,12 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 				nr_succeeded++;
 				break;
 			default:
-				/* Permanent failure */
+				/*
+				 * Permanent failure (-EBUSY, -ENOSYS, etc.):
+				 * unlike -EAGAIN case, the failed page is
+				 * removed from migration page list and not
+				 * retried in the next outer loop.
+				 */
 				nr_failed++;
 				break;
 			}