[PATCH] zoned vm counters: conversion of nr_pagecache to per zone counter

Currently a single atomic variable is used to establish the size of the page
cache in the whole machine.  The zoned VM counters have the same method of
implementation as the nr_pagecache code but also allow the determination of
the pagecache size per zone.

Remove the special implementation for nr_pagecache and make it a zoned counter
named NR_FILE_PAGES.

Updates of the page cache counters are always performed with interrupts off.
We can therefore use the __ variant here.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
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 eb42c12..08be91e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -49,7 +49,7 @@
 enum zone_stat_item {
 	NR_FILE_MAPPED,	/* mapped into pagetables.
 			   only modified from process context */
-
+	NR_FILE_PAGES,
 	NR_VM_ZONE_STAT_ITEMS };
 
 struct per_cpu_pages {