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 e1f784f4b4db..72c936d3e332 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);