[PATCH] Add node to zone for the NUMA case

Add the node in order to optimize zone_to_nid.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Acked-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/linux/mm.h

@@ -446,7 +446,11 @@ static inline struct zone *page_zone(struct page *page)
 
 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)

include/linux/mmzone.h

@@ -168,6 +168,7 @@ struct zone {
 	unsigned long		lowmem_reserve[MAX_NR_ZONES];
 
 #ifdef CONFIG_NUMA
+	int node;
 	/*
 	 * zone reclaim becomes active if more unmapped pages exist.
 	 */

mm/page_alloc.c

@@ -2405,6 +2405,7 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
 		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;