Add set preempt need resched on every call to set_tsk_need_resched where
explicit reschedule does not occur.

---
 kernel/sched/bfs.c |   22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

Index: linux-3.16-ck1/kernel/sched/bfs.c
===================================================================
--- linux-3.16-ck1.orig/kernel/sched/bfs.c	2014-08-22 17:07:04.000000000 +1000
+++ linux-3.16-ck1/kernel/sched/bfs.c	2014-08-22 20:17:51.925549648 +1000
@@ -1179,6 +1179,13 @@ static inline void return_task(struct ta
 	}
 }
 
+/* Enter with grq lock held. We know p is on the local cpu */
+static inline void __set_tsk_resched(struct task_struct *p)
+{
+	set_tsk_need_resched(p);
+	set_preempt_need_resched();
+}
+
 /*
  * resched_task - mark a task 'to be rescheduled now'.
  *
@@ -1788,7 +1795,7 @@ after_ts_init:
 			 * do child-runs-first in anticipation of an exec. This
 			 * usually avoids a lot of COW overhead.
 			 */
-			set_tsk_need_resched(parent);
+			__set_tsk_resched(parent);
 		} else
 			try_preempt(p, rq);
 	} else {
@@ -1800,7 +1807,7 @@ after_ts_init:
 		 	* be slightly earlier.
 		 	*/
 			rq->rq_time_slice = 0;
-			set_tsk_need_resched(parent);
+			__set_tsk_resched(parent);
 		}
 		time_slice_expired(p);
 	}
@@ -2925,9 +2932,10 @@ static void task_running_tick(struct rq
 
 	/* p->time_slice < RESCHED_US. We only modify task_struct under grq lock */
 	p = rq->curr;
+
 	grq_lock();
 	requeue_task(p);
-	set_tsk_need_resched(p);
+	__set_tsk_resched(p);
 	grq_unlock();
 }
 
@@ -4757,9 +4765,9 @@ EXPORT_SYMBOL(yield);
  */
 int __sched yield_to(struct task_struct *p, bool preempt)
 {
+	struct rq *rq, *p_rq;
 	unsigned long flags;
 	int yielded = 0;
-	struct rq *rq;
 
 	rq = this_rq();
 	grq_lock_irqsave(&flags);
@@ -4767,6 +4775,8 @@ int __sched yield_to(struct task_struct
 		yielded = -ESRCH;
 		goto out_unlock;
 	}
+
+	p_rq = task_rq(p);
 	yielded = 1;
 	if (p->deadline > rq->rq_deadline)
 		p->deadline = rq->rq_deadline;
@@ -4774,7 +4784,8 @@ int __sched yield_to(struct task_struct
 	rq->rq_time_slice = 0;
 	if (p->time_slice > timeslice())
 		p->time_slice = timeslice();
-	set_tsk_need_resched(rq->curr);
+	if (preempt && rq != rq)
+		resched_task(p_rq->curr);
 out_unlock:
 	grq_unlock_irqrestore(&flags);
 
@@ -5040,7 +5051,6 @@ void init_idle(struct task_struct *idle,
 #if defined(CONFIG_SMP)
 	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
 #endif
-	set_tsk_need_resched(idle);
 }
 
 void resched_cpu(int cpu)