sched: rt: account the cpu time during the tick

Realtime tasks would not account their runtime during ticks. Which would lead
to:

struct sched_param param = { .sched_priority = 10 };
pthread_setschedparam(pthread_self(), SCHED_FIFO, &param);

while (1) ;

Not showing up in top.

Signed-off-by: Peter Zijlstra <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>

kernel/sched_rt.c

···
 
 static void task_tick_rt(struct rq *rq, struct task_struct *p)
 {
+	update_curr_rt(rq);
+
 	/*
 	 * RR tasks need a special form of timeslice management.
 	 * FIFO tasks have no timeslices.