sched: rework enqueue/dequeue_entity() to get rid of set_curr_task()

rework enqueue/dequeue_entity() to get rid of 
sched_class::set_curr_task(). This simplifies sched_setscheduler(), 
rt_mutex_setprio() and sched_move_tasks().

   text    data     bss     dec     hex filename
  24330    2734      20   27084    69cc sched.o.before
  24233    2730      20   26983    6967 sched.o.after

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 26 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index e1f784f4b4d..72c936d3e33 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3915,8 +3915,8 @@ EXPORT_SYMBOL(sleep_on_timeout);
  */
 void rt_mutex_setprio(struct task_struct *p, int prio)
 {
-	int oldprio, on_rq, running;
 	unsigned long flags;
+	int oldprio, on_rq;
 	struct rq *rq;
 
 	BUG_ON(prio < 0 || prio > MAX_PRIO);
@@ -3926,12 +3926,8 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
 
 	oldprio = p->prio;
 	on_rq = p->se.on_rq;
-	running = task_running(rq, p);
-	if (on_rq) {
+	if (on_rq)
 		dequeue_task(rq, p, 0);
-		if (running)
-			p->sched_class->put_prev_task(rq, p);
-	}
 
 	if (rt_prio(prio))
 		p->sched_class = &rt_sched_class;
@@ -3941,15 +3937,13 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
 	p->prio = prio;
 
 	if (on_rq) {
-		if (running)
-			p->sched_class->set_curr_task(rq);
 		enqueue_task(rq, p, 0);
 		/*
 		 * Reschedule if we are currently running on this runqueue and
 		 * our priority decreased, or if we are not currently running on
 		 * this runqueue and our priority is higher than the current's
 		 */
-		if (running) {
+		if (task_running(rq, p)) {
 			if (p->prio > oldprio)
 				resched_task(rq->curr);
 		} else {
@@ -4155,7 +4149,7 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
 int sched_setscheduler(struct task_struct *p, int policy,
 		       struct sched_param *param)
 {
-	int retval, oldprio, oldpolicy = -1, on_rq, running;
+	int retval, oldprio, oldpolicy = -1, on_rq;
 	unsigned long flags;
 	struct rq *rq;
 
@@ -4237,24 +4231,20 @@ recheck:
 	}
 	update_rq_clock(rq);
 	on_rq = p->se.on_rq;
-	running = task_running(rq, p);
-	if (on_rq) {
+	if (on_rq)
 		deactivate_task(rq, p, 0);
-		if (running)
-			p->sched_class->put_prev_task(rq, p);
-	}
+
 	oldprio = p->prio;
 	__setscheduler(rq, p, policy, param->sched_priority);
+
 	if (on_rq) {
-		if (running)
-			p->sched_class->set_curr_task(rq);
 		activate_task(rq, p, 0);
 		/*
 		 * Reschedule if we are currently running on this runqueue and
 		 * our priority decreased, or if we are not currently running on
 		 * this runqueue and our priority is higher than the current's
 		 */
-		if (running) {
+		if (task_running(rq, p)) {
 			if (p->prio > oldprio)
 				resched_task(rq->curr);
 		} else {
@@ -6855,19 +6845,13 @@ static void sched_move_task(struct container_subsys *ss, struct container *cont,
 	running = task_running(rq, tsk);
 	on_rq = tsk->se.on_rq;
 
-	if (on_rq) {
+	if (on_rq)
 		dequeue_task(rq, tsk, 0);
-		if (unlikely(running))
-			tsk->sched_class->put_prev_task(rq, tsk);
-	}
 
 	set_task_cfs_rq(tsk);
 
-	if (on_rq) {
-		if (unlikely(running))
-			tsk->sched_class->set_curr_task(rq);
+	if (on_rq)
 		enqueue_task(rq, tsk, 0);
-	}
 
 done:
 	task_rq_unlock(rq, &flags);