[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/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d89f6fb..26b1fe9 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -315,6 +315,7 @@
 						req->wb_index, NFS_PAGE_TAG_DIRTY);
 				nfs_list_remove_request(req);
 				nfs_list_add_request(req, dst);
+				dec_zone_page_state(req->wb_page, NR_FILE_DIRTY);
 				res++;
 			}
 		}