[PATCH] Use ZVC for free_pages

This is again simplifies some of the VM counter calculations through the use
of the ZVC consolidated counters.

[michal.k.k.piotrowski@gmail.com: build fix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mmzone.h

@@ -47,6 +47,7 @@ struct zone_padding {
 #endif
 
 enum zone_stat_item {
+	NR_FREE_PAGES,
 	NR_INACTIVE,
 	NR_ACTIVE,
 	NR_ANON_PAGES,	/* Mapped anonymous pages */
@@ -157,7 +158,6 @@ enum zone_type {
 
 struct zone {
 	/* Fields commonly accessed by the page allocator */
-	unsigned long		free_pages;
 	unsigned long		pages_min, pages_low, pages_high;
 	/*
 	 * We don't know if the memory that we're going to allocate will be freeable