[PATCH 05/13] writeback: account per-bdi accumulated written pages

[Wu Fengguang <fengguang.wu@intel.com>]

Andrew,
References: <20101117035821.000579293@intel.com>
Content-Disposition: inline; filename=writeback-bdi-written.patch

From: Jan Kara <jack@suse.cz>

Introduce the BDI_WRITTEN counter. It will be used for estimating the
bdi's write bandwidth.

Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 include/linux/backing-dev.h |    1 +
 mm/backing-dev.c            |    6 ++++--
 mm/page-writeback.c         |    1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

--- linux-next.orig/include/linux/backing-dev.h	2010-11-16 22:48:28.000000000 +0800
+++ linux-next/include/linux/backing-dev.h	2010-11-17 00:18:56.000000000 +0800
@@ -40,6 +40,7 @@ typedef int (congested_fn)(void *, int);
 enum bdi_stat_item {
 	BDI_RECLAIMABLE,
 	BDI_WRITEBACK,
+	BDI_WRITTEN,
 	NR_BDI_STAT_ITEMS
 };
 
--- linux-next.orig/mm/backing-dev.c	2010-11-16 22:48:28.000000000 +0800
+++ linux-next/mm/backing-dev.c	2010-11-17 00:18:56.000000000 +0800
@@ -92,6 +92,7 @@ static int bdi_debug_stats_show(struct s
 		   "BdiDirtyThresh:   %8lu kB\n"
 		   "DirtyThresh:      %8lu kB\n"
 		   "BackgroundThresh: %8lu kB\n"
+		   "BdiWritten:       %8lu kB\n"
 		   "b_dirty:          %8lu\n"
 		   "b_io:             %8lu\n"
 		   "b_more_io:        %8lu\n"
@@ -99,8 +100,9 @@ static int bdi_debug_stats_show(struct s
 		   "state:            %8lx\n",
 		   (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
 		   (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
-		   K(bdi_thresh), K(dirty_thresh),
-		   K(background_thresh), nr_dirty, nr_io, nr_more_io,
+		   K(bdi_thresh), K(dirty_thresh), K(background_thresh),
+		   (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
+		   nr_dirty, nr_io, nr_more_io,
 		   !list_empty(&bdi->bdi_list), bdi->state);
 #undef K
 
--- linux-next.orig/mm/page-writeback.c	2010-11-17 00:18:54.000000000 +0800
+++ linux-next/mm/page-writeback.c	2010-11-17 00:18:56.000000000 +0800
@@ -1292,6 +1292,7 @@ int test_clear_page_writeback(struct pag
 						PAGECACHE_TAG_WRITEBACK);
 			if (bdi_cap_account_writeback(bdi)) {
 				__dec_bdi_stat(bdi, BDI_WRITEBACK);
+				__inc_bdi_stat(bdi, BDI_WRITTEN);
 				__bdi_writeout_inc(bdi);
 			}
 		}