From: Andrew Morton <akpm@osdl.org>

As Nick points out, only ia64 uses PG_uncached.  So we can push it up into the
higher 32-bits of page->flags and make room for another flag on 32-bit
machines.

Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Jesse Barnes <jbarnes@sgi.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 include/linux/mmzone.h     |    2 +-
 include/linux/page-flags.h |    7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff -puN include/linux/page-flags.h~pg_uncached-is-ia64-only include/linux/page-flags.h
--- devel/include/linux/page-flags.h~pg_uncached-is-ia64-only	2006-04-06 21:50:51.000000000 -0700
+++ devel-akpm/include/linux/page-flags.h	2006-04-06 21:50:51.000000000 -0700
@@ -7,6 +7,8 @@
 
 #include <linux/percpu.h>
 #include <linux/cache.h>
+#include <linux/types.h>
+
 #include <asm/pgtable.h>
 
 /*
@@ -86,7 +88,10 @@
 #define PG_mappedtodisk		16	/* Has blocks allocated on-disk */
 #define PG_reclaim		17	/* To be reclaimed asap */
 #define PG_nosave_free		18	/* Free, should not be written */
-#define PG_uncached		19	/* Page has been mapped as uncached */
+
+#if (BITS_PER_LONG > 32)
+#define PG_uncached		32	/* Page has been mapped as uncached */
+#endif
 
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
diff -puN include/linux/mmzone.h~pg_uncached-is-ia64-only include/linux/mmzone.h
--- devel/include/linux/mmzone.h~pg_uncached-is-ia64-only	2006-04-06 21:50:56.000000000 -0700
+++ devel-akpm/include/linux/mmzone.h	2006-04-06 21:51:12.000000000 -0700
@@ -457,7 +457,7 @@ extern struct zone *next_zone(struct zon
 /*
  * with 64 bit flags field, there's plenty of room.
  */
-#define FLAGS_RESERVED		32
+#define FLAGS_RESERVED		24
 
 #else
 
_