Index: linux-2.6.18-mm2/include/linux/mm.h
===================================================================
--- linux-2.6.18-mm2.orig/include/linux/mm.h	2006-09-30 13:23:06.604463587 -0500
+++ linux-2.6.18-mm2/include/linux/mm.h	2006-10-02 13:59:45.478225851 -0500
@@ -421,7 +421,12 @@ void split_page(struct page *page, unsig
 #else
 #define ZONEID_SHIFT		(NODES_SHIFT + ZONES_SHIFT)
 #endif
+
+#if ZONES_WIDTH > 0
 #define ZONEID_PGSHIFT		ZONES_PGSHIFT
+#else
+#define ZONEID_PGSHIFT		NODES_PGOFF
+#endif
 
 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED