1 files changed, 10 insertions, 3 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 9c1c199f88ce..a9a08d88a745 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -439,10 +439,17 @@ static int bdi_forker_thread(void *ptr)
                         break;
 
                 case NO_ACTION:
-                        if (dirty_writeback_interval)
-                                schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
+                        if (!wb_has_dirty_io(me) || !dirty_writeback_interval)
+                                /*
+                                 * There are no dirty data. The only thing we
+                                 * should now care about is checking for
+                                 * inactive bdi threads and killing them. Thus,
+                                 * let's sleep for longer time, save energy and
+                                 * be friendly for battery-driven devices.
+                                 */
+                                schedule_timeout(bdi_longest_inactive());
                         else
-                                schedule();
+                                schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
                         try_to_freeze();
                         /* Back to the main loop */
                         continue;