mm: Add comment explaining task state setting in bdi_forker_thread()

CC: Wu Fengguang <[email protected]> CC: Andrew Morton <[email protected]> Signed-off-by: Jan Kara <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
jeffegg · Sep 2, 2011 · 09f40f9 · 09f40f9
1 parent 5a042aa
commit 09f40f9
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
@@ -401,6 +401,13 @@ static int bdi_forker_thread(void *ptr)
 		}
 
 		spin_lock_bh(&bdi_lock);
+		/*
+		 * In the following loop we are going to check whether we have
+		 * some work to do without any synchronization with tasks
+		 * waking us up to do work for them. So we have to set task
+		 * state already here so that we don't miss wakeups coming
+		 * after we verify some condition.
+		 */
 		set_current_state(TASK_INTERRUPTIBLE);
 
 		list_for_each_entry(bdi, &bdi_list, bdi_list) {