writeback: account per-bdi accumulated dirtied pages

Introduce the BDI_DIRTIED counter. It will be used for estimating the
bdi's dirty bandwidth.

CC: Jan Kara <jack@suse.cz>
CC: Michael Rubin <mrubin@google.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0e309cd1b5b9..0e6dd5c2ed31 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1322,6 +1322,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
                 __inc_zone_page_state(page, NR_FILE_DIRTY);
                 __inc_zone_page_state(page, NR_DIRTIED);
                 __inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
+                __inc_bdi_stat(mapping->backing_dev_info, BDI_DIRTIED);
                 task_dirty_inc(current);
                 task_io_account_write(PAGE_CACHE_SIZE);
         }