Merge branches 'pm-cpufreq', 'pm-cpuidle', 'pm-devfreq', 'pm-opp' and 'pm-tools'

[linux-drm-fsl-dcu.git] / kernel / sched / rt.c

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index ee15f5a0d1c1896c1cc6edf2d202c3f1652c87f8..f4d4b077eba0a67a5c55e6a04dee8f6ce78f322c 100644 (file)
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -831,11 +831,14 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
                                enqueue = 1;
 
                                /*
-                                * Force a clock update if the CPU was idle,
-                                * lest wakeup -> unthrottle time accumulate.
+                                * When we're idle and a woken (rt) task is
+                                * throttled check_preempt_curr() will set
+                                * skip_update and the time between the wakeup
+                                * and this unthrottle will get accounted as
+                                * 'runtime'.
                                 */
                                if (rt_rq->rt_nr_running && rq->curr == rq->idle)
-                                       rq->skip_clock_update = -1;
+                                       rq_clock_skip_update(rq, false);
                        }
                        if (rt_rq->rt_time || rt_rq->rt_nr_running)
                                idle = 0;
@@ -1337,7 +1340,12 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
             curr->prio <= p->prio)) {
                int target = find_lowest_rq(p);
 
-               if (target != -1)
+               /*
+                * Don't bother moving it if the destination CPU is
+                * not running a lower priority task.
+                */
+               if (target != -1 &&
+                   p->prio < cpu_rq(target)->rt.highest_prio.curr)
                        cpu = target;
        }
        rcu_read_unlock();
@@ -1614,6 +1622,16 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
 
                lowest_rq = cpu_rq(cpu);
 
+               if (lowest_rq->rt.highest_prio.curr <= task->prio) {
+                       /*
+                        * Target rq has tasks of equal or higher priority,
+                        * retrying does not release any lock and is unlikely
+                        * to yield a different result.
+                        */
+                       lowest_rq = NULL;
+                       break;
+               }
+
                /* if the prio of this runqueue changed, try again */
                if (double_lock_balance(rq, lowest_rq)) {
                        /*