[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/mm/page-writeback.c b/mm/page-writeback.c
index 0faacfe..da85478 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -109,7 +109,7 @@
 
 static void get_writeback_state(struct writeback_state *wbs)
 {
-	wbs->nr_dirty = read_page_state(nr_dirty);
+	wbs->nr_dirty = global_page_state(NR_FILE_DIRTY);
 	wbs->nr_unstable = read_page_state(nr_unstable);
 	wbs->nr_mapped = global_page_state(NR_FILE_MAPPED) +
 				global_page_state(NR_ANON_PAGES);
@@ -641,7 +641,8 @@
 			if (mapping2) { /* Race with truncate? */
 				BUG_ON(mapping2 != mapping);
 				if (mapping_cap_account_dirty(mapping))
-					inc_page_state(nr_dirty);
+					__inc_zone_page_state(page,
+								NR_FILE_DIRTY);
 				radix_tree_tag_set(&mapping->page_tree,
 					page_index(page), PAGECACHE_TAG_DIRTY);
 			}
@@ -728,9 +729,9 @@
 			radix_tree_tag_clear(&mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_DIRTY);
-			write_unlock_irqrestore(&mapping->tree_lock, flags);
 			if (mapping_cap_account_dirty(mapping))
-				dec_page_state(nr_dirty);
+				__dec_zone_page_state(page, NR_FILE_DIRTY);
+			write_unlock_irqrestore(&mapping->tree_lock, flags);
 			return 1;
 		}
 		write_unlock_irqrestore(&mapping->tree_lock, flags);
@@ -761,7 +762,7 @@
 	if (mapping) {
 		if (TestClearPageDirty(page)) {
 			if (mapping_cap_account_dirty(mapping))
-				dec_page_state(nr_dirty);
+				dec_zone_page_state(page, NR_FILE_DIRTY);
 			return 1;
 		}
 		return 0;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ed3f2a7..c2b9aa4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1314,7 +1314,7 @@
 		"unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
 		active,
 		inactive,
-		ps.nr_dirty,
+		global_page_state(NR_FILE_DIRTY),
 		ps.nr_writeback,
 		ps.nr_unstable,
 		nr_free_pages(),
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 292a35f..1982fb5 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -400,9 +400,9 @@
 	"nr_file_pages",
 	"nr_slab",
 	"nr_page_table_pages",
+	"nr_dirty",
 
 	/* Page state */
-	"nr_dirty",
 	"nr_writeback",
 	"nr_unstable",