[PATCH 2/2] GFP_ZONETYPES calculate from GFP_ZONEMASK

[Andy Whitcroft <apw@shadowen.org>]

GFP_ZONETYPES calculate from GFP_ZONEMASK

GFP_ZONETYPES's value is directly related to the value of GFP_ZONEMASK. 
It takes one of two forms depending whether the top bit of GFP_ZONEMASK
is a 'loner'.  Supply both forms, enabling the loner.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
---
 mmzone.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff -upN reference/include/linux/mmzone.h current/include/linux/mmzone.h
--- reference/include/linux/mmzone.h
+++ current/include/linux/mmzone.h
@@ -98,11 +98,14 @@ struct per_cpu_pageset {
  * of three zone modifier bits, we could require up to eight zonelists.
  * If the left most zone modifier is a "loner" then the highest valid
  * zonelist would be four allowing us to allocate only five zonelists.
+ * Use the first form for GFP_ZONETYPES when the left most bit is not
+ * a "loner", otherwise use the second.
  *
  * NOTE! Make sure this matches the zones in <linux/gfp.h>
  */
 #define GFP_ZONEMASK	0x07
-#define GFP_ZONETYPES	5
+/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */
+#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */
 
 /*
  * On machines where it is needed (eg PCs) we divide physical memory