[PATCH] reduce MAX_NR_ZONES: make ZONE_DMA32 optional

Make ZONE_DMA32 optional

- Add #ifdefs around ZONE_DMA32 specific code and definitions.

- Add CONFIG_ZONE_DMA32 config option and use that for x86_64
  that alone needs this zone.

- Remove the use of CONFIG_DMA_IS_DMA32 and CONFIG_DMA_IS_NORMAL
  for ia64 and fix up the way per node ZVCs are calculated.

- Fall back to prior GFP_ZONEMASK of 0x03 if there is no
  DMA32 zone.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 3 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 03a5a6eb0ffa..adae3c915938 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -109,12 +109,14 @@ enum zone_type {
          *                      <16M.
          */
         ZONE_DMA,
+#ifdef CONFIG_ZONE_DMA32
         /*
          * x86_64 needs two ZONE_DMAs because it supports devices that are
          * only able to do DMA to the lower 16M but also 32 bit devices that
          * can only do DMA areas below 4G.
          */
         ZONE_DMA32,
+#endif
         /*
          * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
          * performed on pages in ZONE_NORMAL if the DMA devices support
@@ -161,9 +163,13 @@ enum zone_type {
  *
  * NOTE! Make sure this matches the zones in <linux/gfp.h>
  */
-#define GFP_ZONEMASK    0x07
-/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */
-#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */
+#define GFP_ZONETYPES           ((GFP_ZONEMASK + 1) / 2 + 1)    /* Loner */
+
+#ifdef CONFIG_ZONE_DMA32
+#define GFP_ZONEMASK            0x07
+#else
+#define GFP_ZONEMASK            0x03
+#endif
 
 struct zone {
         /* Fields commonly accessed by the page allocator */
@@ -429,7 +435,11 @@ static inline int is_normal(struct zone *zone)
 
 static inline int is_dma32(struct zone *zone)
 {
+#ifdef CONFIG_ZONE_DMA32
         return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
+#else
+        return 0;
+#endif
 }
 
 static inline int is_dma(struct zone *zone)