writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account

[firefly-linux-kernel-4.4.55.git] / include / linux / backing-dev-defs.h

diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index d631a61f40237bfde6f810447ad13d760aea63c1..8c857d723023260e6b7aa117e53b143af41a8a26 100644 (file)
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -98,7 +98,7 @@ struct bdi_writeback {
        unsigned long dirtied_stamp;
        unsigned long written_stamp;    /* pages written at bw_time_stamp */
        unsigned long write_bandwidth;  /* the estimated write bandwidth */
-       unsigned long avg_write_bandwidth; /* further smoothed write bw */
+       unsigned long avg_write_bandwidth; /* further smoothed write bw, > 0 */
 
        /*
         * The base dirty throttle rate, re-calculated on every 200ms.
@@ -142,7 +142,11 @@ struct backing_dev_info {
        unsigned int min_ratio;
        unsigned int max_ratio, max_prop_frac;
 
-       atomic_long_t tot_write_bandwidth; /* sum of active avg_write_bw */
+       /*
+        * Sum of avg_write_bw of wbs with dirty inodes.  > 0 if there are
+        * any dirty wbs, which is depended upon by bdi_has_dirty().
+        */
+       atomic_long_t tot_write_bandwidth;
 
        struct bdi_writeback wb;  /* the root writeback info for this bdi */
        struct bdi_writeback_congested wb_congested; /* its congested state */