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

This makes nr_dirty a per zone counter.  Looping over all processors is
avoided during writeback state determination.

The counter aggregation for nr_dirty had to be undone in the NFS layer since
we summed up the page counts from multiple zones.  Someone more familiar with
NFS should probably review what I have done.

[akpm@osdl.org: bugfix]
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/drivers/base/node.c b/drivers/base/node.c
index c22fb67e..6fed520 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -50,8 +50,6 @@
 	__get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
 
 	/* Check for negative values in these approximate counters */
-	if ((long)ps.nr_dirty < 0)
-		ps.nr_dirty = 0;
 	if ((long)ps.nr_writeback < 0)
 		ps.nr_writeback = 0;
 
@@ -81,7 +79,7 @@
 		       nid, K(i.freehigh),
 		       nid, K(i.totalram - i.totalhigh),
 		       nid, K(i.freeram - i.freehigh),
-		       nid, K(ps.nr_dirty),
+		       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
 		       nid, K(ps.nr_writeback),
 		       nid, K(node_page_state(nid, NR_FILE_PAGES)),
 		       nid, K(node_page_state(nid, NR_FILE_MAPPED)),