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, 2 insertions, 0 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index a87da524a4a0..fea7e6efd1d7 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -97,6 +97,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
                    "BdiDirtyThresh:     %10lu kB\n"
                    "DirtyThresh:        %10lu kB\n"
                    "BackgroundThresh:   %10lu kB\n"
+                   "BdiDirtied:         %10lu kB\n"
                    "BdiWritten:         %10lu kB\n"
                    "BdiWriteBandwidth:  %10lu kBps\n"
                    "b_dirty:            %10lu\n"
@@ -109,6 +110,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
                    K(bdi_thresh),
                    K(dirty_thresh),
                    K(background_thresh),
+                   (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
                    (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
                    (unsigned long) K(bdi->write_bandwidth),
                    nr_dirty,