diff --git a/src/threads/thread.c b/src/threads/thread.c
index 146a430..709fcef 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -256,7 +256,7 @@ thread_unblock (struct thread *t)
 
   old_level = intr_disable ();
   ASSERT (t->status == THREAD_BLOCKED);
-  list_push_back (&ready_list, &t->elem);
+  list_insert_ordered (&ready_list, &t->elem, &thread_priority_greater, NULL);
   t->status = THREAD_READY;
   intr_set_level (old_level);
 }
@@ -327,7 +327,8 @@ thread_yield (void)
 
   old_level = intr_disable ();
   if (cur != idle_thread) 
-    list_push_back (&ready_list, &cur->elem);
+    list_insert_ordered (&ready_list, &cur->elem, thread_priority_greater,
+                         NULL);
   cur->status = THREAD_READY;
   schedule ();
   intr_set_level (old_level);