sched: add set_curr_task() calls

p->sched_class->set_curr_task() has to be called before 
activate_task()/enqueue_task() in rt_mutex_setprio(), 
sched_setschedule() and sched_move_task() in order to set up 
'cfs_rq->curr'. The logic of enqueueing depends on whether a task to be 
inserted is 'current' or not.

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.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, 13 insertions, 9 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index b2688ce54b11..6d1892192e21 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);
@@ -3926,9 +3926,10 @@ 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) {
                 dequeue_task(rq, p, 0);
-                if (task_running(rq, p))
+                if (running)
                         p->sched_class->put_prev_task(rq, p);
         }
 
@@ -3940,16 +3941,17 @@ 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 (task_running(rq, p)) {
+                if (running) {
                         if (p->prio > oldprio)
                                 resched_task(rq->curr);
-                        p->sched_class->set_curr_task(rq);
                 } else {
                         check_preempt_curr(rq, p);
                 }
@@ -4153,7 +4155,7 @@ __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;
+        int retval, oldprio, oldpolicy = -1, on_rq, running;
         unsigned long flags;
         struct rq *rq;
 
@@ -4235,24 +4237,26 @@ recheck:
         }
         update_rq_clock(rq);
         on_rq = p->se.on_rq;
+        running = task_running(rq, p);
         if (on_rq) {
                 deactivate_task(rq, p, 0);
-                if (task_running(rq, p))
+                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 (task_running(rq, p)) {
+                if (running) {
                         if (p->prio > oldprio)
                                 resched_task(rq->curr);
-                        p->sched_class->set_curr_task(rq);
                 } else {
                         check_preempt_curr(rq, p);
                 }
@@ -6861,9 +6865,9 @@ static void sched_move_task(struct container_subsys *ss, struct container *cont,
         set_task_cfs_rq(tsk);
 
         if (on_rq) {
-                enqueue_task(rq, tsk, 0);
                 if (unlikely(running))
                         tsk->sched_class->set_curr_task(rq);
+                enqueue_task(rq, tsk, 0);
         }
 
 done: