diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e31dea9..c95eb24 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -881,6 +881,9 @@
 		avg += (old - avg) >> 3;
 
 out:
+	if (wb_has_dirty_io(wb))
+		atomic_long_add(avg - wb->avg_write_bandwidth,
+				&wb->bdi->tot_write_bandwidth);
 	wb->write_bandwidth = bw;
 	wb->avg_write_bandwidth = avg;
 }