diff --git a/lib/workqueue.h b/lib/workqueue.h
index 7e0e78a..3150c32 100644
--- a/lib/workqueue.h
+++ b/lib/workqueue.h
@@ -47,11 +47,8 @@
   unsigned short ran;			/* # of times item has been run */
 };
 
-enum work_queue_flags
-{
-  WQ_UNPLUGGED = 0,
-  WQ_PLUGGED = 1,
-};
+#define WQ_UNPLUGGED	(1 << 0) /* available for draining */
+#define WQ_AIM_HEAD	(1 << 1) /* add new items before list head, not after tail */
 
 struct work_queue
 {
@@ -101,7 +98,7 @@
   } cycles;	/* cycle counts */
   
   /* private state */
-  enum work_queue_flags flags;		/* user set flag */
+  u_int16_t flags;		/* user set flag */
 };
 
 /* User API */
@@ -122,6 +119,8 @@
 extern void work_queue_plug (struct work_queue *wq);
 /* unplug the queue, allow it to be drained again */
 extern void work_queue_unplug (struct work_queue *wq);
+/* control the value for WQ_AIM_HEAD flag */
+extern void work_queue_aim_head (struct work_queue *wq, const unsigned);
 
 /* Helpers, exported for thread.c and command.c */
 extern int work_queue_run (struct thread *);