Index: linux-2.6.30-bfs014/kernel/sched_bfs.c
===================================================================
--- linux-2.6.30-bfs014.orig/kernel/sched_bfs.c	2009-08-25 16:16:30.826750871 +1000
+++ linux-2.6.30-bfs014/kernel/sched_bfs.c	2009-08-25 16:43:53.828049190 +1000
@@ -283,13 +283,6 @@
 #endif
 }
 
-static inline void time_lock_rq(struct rq *rq)
-	__acquires(grq.lock)
-{
-	spin_lock(&grq.lock);
-	update_rq_clock(rq);
-}
-
 static inline int task_running(struct task_struct *p)
 {
 	return (!!p->oncpu);
@@ -313,6 +306,13 @@
 	spin_lock_irq(&grq.lock);
 }
 
+static inline void time_lock_rq(struct rq *rq)
+	__acquires(grq.lock)
+{
+	grq_lock();
+	update_rq_clock(rq);
+}
+
 static inline void grq_unlock_irq(void)
 	__releases(grq.lock)
 {
@@ -491,14 +491,9 @@
 	sched_info_queued(p);
 }
 
-/*
- * Requeue a running task that's running. The position in the run list is
- * irrelevant for SCHED_NORMAL tasks. RT tasks only need moving.
- */
+/* No need to do anything, it happens on return_task */
 static inline void requeue_task(struct task_struct *p)
 {
-	if (rt_task(p))
-		list_move_tail(&p->run_list, grq.queue + p->prio);
 	sched_info_queued(p);
 }
 
@@ -1863,18 +1858,25 @@
 #endif
 
 /*
- * Deadline is "now" in jiffies + (offset by priority).
+ * Deadline is "now" in jiffies + (offset by priority). Setting the deadline
+ * is the key to everything. It distributes cpu fairly amongst tasks of the
+ * same nice value, it proportions cpu according to nice level, it means the
+ * task that last woke up the longest ago has the earliest deadline, thus
+ * ensuring that interactive tasks get low latency on wake up.
  */
-static inline void set_deadline(struct task_struct *p)
+static inline void time_slice_expired(struct task_struct *p)
 {
-	if (p->time_slice > 0 || rt_task(p))
-		return;
-
 	reset_first_time_slice(p);
 	p->time_slice = timeslice();
 	p->deadline = jiffies + (prio_ratio(p) * rr_interval * HZ / 1000 / 100);
 }
 
+static inline void check_deadline(struct task_struct *p)
+{
+	if (p->time_slice <= 0)
+		time_slice_expired(p);
+}
+
 static inline int longest_deadline(void)
 {
 	return (prio_ratios[39] * rr_interval * HZ / 100) + 1;
@@ -2034,7 +2036,7 @@
 	}
 
 	if (prev != rq->idle) {
-		set_deadline(prev);
+		check_deadline(prev);
 		return_task(prev, deactivate);
 	}
 
@@ -3191,12 +3193,12 @@
  */
 SYSCALL_DEFINE0(sched_yield)
 {
-	struct task_struct *p = current;
+	struct task_struct *p;
 
 	grq_lock_irq();
+	p = current;
 	schedstat_inc(this_rq(), yld_count);
-	if (!rt_task(p))
-		p->deadline = jiffies + longest_deadline();
+	time_slice_expired(p);
 	requeue_task(p);
 
 	/*