[PATCH] sparsemem base: reorganize page->flags bit operations
Generify the value fields in the page_flags. The aim is to allow the location
and size of these fields to be varied. Additionally we want to move away from
fixed allocations per field whilst still enforcing the overall bit utilisation
limits. We rely on the compiler to spot and optimise the accessor functions.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index b79633d..39e9127 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -414,30 +414,25 @@
#include <asm/mmzone.h>
+#endif /* !CONFIG_DISCONTIGMEM */
+
#if BITS_PER_LONG == 32 || defined(ARCH_HAS_ATOMIC_UNSIGNED)
/*
* with 32 bit page->flags field, we reserve 8 bits for node/zone info.
* there are 3 zones (2 bits) and this leaves 8-2=6 bits for nodes.
*/
-#define MAX_NODES_SHIFT 6
+#define FLAGS_RESERVED 8
+
#elif BITS_PER_LONG == 64
/*
* with 64 bit flags field, there's plenty of room.
*/
-#define MAX_NODES_SHIFT 10
-#endif
+#define FLAGS_RESERVED 32
-#endif /* !CONFIG_DISCONTIGMEM */
+#else
-#if NODES_SHIFT > MAX_NODES_SHIFT
-#error NODES_SHIFT > MAX_NODES_SHIFT
-#endif
+#error BITS_PER_LONG not defined
-/* There are currently 3 zones: DMA, Normal & Highmem, thus we need 2 bits */
-#define MAX_ZONES_SHIFT 2
-
-#if ZONES_SHIFT > MAX_ZONES_SHIFT
-#error ZONES_SHIFT > MAX_ZONES_SHIFT
#endif
#endif /* !__ASSEMBLY__ */