[PATCH] Add node to zone for the NUMA case

Add the node in order to optimize zone_to_nid.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7477fb5..8e433bb 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -446,7 +446,11 @@
 
 static inline unsigned long zone_to_nid(struct zone *zone)
 {
-	return zone->zone_pgdat->node_id;
+#ifdef CONFIG_NUMA
+	return zone->node;
+#else
+	return 0;
+#endif
 }
 
 static inline unsigned long page_to_nid(struct page *page)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 562cf7a..59855b8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -168,6 +168,7 @@
 	unsigned long		lowmem_reserve[MAX_NR_ZONES];
 
 #ifdef CONFIG_NUMA
+	int node;
 	/*
 	 * zone reclaim becomes active if more unmapped pages exist.
 	 */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4c76188..d0432e4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2405,6 +2405,7 @@
 		zone->spanned_pages = size;
 		zone->present_pages = realsize;
 #ifdef CONFIG_NUMA
+		zone->node = nid;
 		zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
 						/ 100;
 		zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;