diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 4dabf0f..5bc4fa5 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -108,6 +108,7 @@
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	PG_compound_lock,
 #endif
+	PG_readahead,		/* page in a readahead window */
 	__NR_PAGEFLAGS,
 
 	/* Filesystems */