[PATCH] reduce MAX_NR_ZONES: use enum to define zones, reformat and comment

Use enum for zones and reformat zones dependent information

Add comments explaning the use of zones and add a zones_t type for zone
numbers.

Line up information that will be #ifdefd by the following patches.

[akpm@osdl.org: comment cleanups]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 13c102b..2410a3c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -68,7 +68,11 @@
  * TBD: should special case ZONE_DMA32 machines here - in those we normally
  * don't need any ZONE_NORMAL reservation
  */
-int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };
+int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
+	 256,
+	 256,
+	 32
+};
 
 EXPORT_SYMBOL(totalram_pages);
 
@@ -79,7 +83,13 @@
 struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
 EXPORT_SYMBOL(zone_table);
 
-static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };
+static char *zone_names[MAX_NR_ZONES] = {
+	 "DMA",
+	 "DMA32",
+	 "Normal",
+	 "HighMem"
+};
+
 int min_free_kbytes = 1024;
 
 unsigned long __meminitdata nr_kernel_pages;
@@ -1487,7 +1497,9 @@
 
 static void __meminit build_zonelists(pg_data_t *pgdat)
 {
-	int i, j, k, node, local_node;
+	int i, node, local_node;
+	enum zone_type k;
+	enum zone_type j;
 
 	local_node = pgdat->node_id;
 	for (i = 0; i < GFP_ZONETYPES; i++) {
@@ -1675,8 +1687,8 @@
 }
 
 #define ZONETABLE_INDEX(x, zone_nr)	((x << ZONES_SHIFT) | zone_nr)
-void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
-		unsigned long size)
+void zonetable_add(struct zone *zone, int nid, enum zone_type zid,
+		unsigned long pfn, unsigned long size)
 {
 	unsigned long snum = pfn_to_section_nr(pfn);
 	unsigned long end = pfn_to_section_nr(pfn + size);
@@ -1960,7 +1972,7 @@
 static void __meminit free_area_init_core(struct pglist_data *pgdat,
 		unsigned long *zones_size, unsigned long *zholes_size)
 {
-	unsigned long j;
+	enum zone_type j;
 	int nid = pgdat->node_id;
 	unsigned long zone_start_pfn = pgdat->node_start_pfn;
 	int ret;