writeback: track if we're sleeping on progress in balance_dirty_pages()
Note in the bdi_writeback structure whenever a task ends up sleeping
waiting for progress. We can use that information in the lower layers
to increase the priority of writes.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 439cc63..52e2f8e 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1778,6 +1778,7 @@ static void balance_dirty_pages(struct address_space *mapping,
pause,
start_time);
__set_current_state(TASK_KILLABLE);
+ wb->dirty_sleep = now;
io_schedule_timeout(pause);
current->dirty_paused_when = now + pause;
