--- a/runqueue.c
+++ b/runqueue.c
@@ -34,6 +34,58 @@ void runqueue_init(struct runqueue *q)
	INIT_SAFE_LIST(&q->tasks_inactive);
 }

+static struct runqueue_task *get_next_task_from_inactive_list(struct runqueue *q)
+{
+	struct runqueue_task *t, *tmp_node = NULL;
+	struct list_head *inactive_node,*active_node;
+	unsigned int i;
+
+	list_for_each(inactive_node, &q->tasks_inactive.list) {
+		t = container_of(inactive_node, struct runqueue_task, list.list);
+		if(tmp_node == t) {
+			//fprintf(stderr, "only depend task!\n");
+			return NULL;
+		}
+		if(!t->depend_task_num)
+			return t;
+		list_for_each(active_node, &q->tasks_active.list) {
+			for(i=0; i<t->depend_task_num; i++) {
+				if(container_of(active_node, struct runqueue_task,
+					list.list) == t->depend_task[i]) {
+						if(inactive_node == &q->tasks_inactive.list)
+							return NULL;
+						else
+							inactive_node = inactive_node->next;
+						safe_list_del(&t->list);
+						safe_list_add(&t->list, &q->tasks_inactive);
+						inactive_node = inactive_node->prev;
+						if(!tmp_node)
+							tmp_node = t;
+						goto ExitActiveErgo;
+				}
+			}
+		}
+ExitActiveErgo:
+		if(!tmp_node) {
+			struct list_head *node;
+			struct runqueue_task *depend_inactive_node = NULL;
+			list_for_each(node, &q->tasks_inactive.list) {
+				for(i=0; i<t->depend_task_num; i++) {
+					if(container_of(node, struct runqueue_task,
+						list.list) == t->depend_task[i]) {
+						if(!depend_inactive_node)
+							depend_inactive_node = t;
+					}
+				}
+			}
+			if(!depend_inactive_node)
+				return t;
+		}
+	}
+
+	return NULL;
+}
+
 static void __runqueue_start_next(struct uloop_timeout *timeout)
 {
	struct runqueue *q = container_of(timeout, struct runqueue, timeout);
@@ -48,10 +100,12 @@ static void __runqueue_start_next(struct

		if (q->max_running_tasks && q->running_tasks >= q->max_running_tasks)
			break;
-
-		t = list_first_entry(&q->tasks_inactive.list, struct runqueue_task, list.list);
+		t = get_next_task_from_inactive_list(q);
+		if(t == NULL)
+			break;
		safe_list_del(&t->list);
		safe_list_add(&t->list, &q->tasks_active);
+
		t->running = true;
		q->running_tasks++;
		if (t->run_timeout)
--- a/runqueue.h
+++ b/runqueue.h
@@ -80,6 +80,9 @@ struct runqueue_task {
	int cancel_timeout;
	int cancel_type;

+	unsigned int depend_task_num;
+	struct runqueue_task **depend_task;
+
	bool queued;
	bool running;
	bool cancelled;