+struct rt_bandwidth {
+ ktime_t rt_period;
+ u64 rt_runtime;
+ struct hrtimer rt_period_timer;
+};
+
+static struct rt_bandwidth def_rt_bandwidth;
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
+
+static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
+{
+ struct rt_bandwidth *rt_b =
+ container_of(timer, struct rt_bandwidth, rt_period_timer);
+ ktime_t now;
+ int overrun;
+ int idle = 0;
+
+ for (;;) {
+ now = hrtimer_cb_get_time(timer);
+ overrun = hrtimer_forward(timer, now, rt_b->rt_period);
+
+ if (!overrun)
+ break;
+
+ idle = do_sched_rt_period_timer(rt_b, overrun);
+ }
+
+ return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+static
+void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
+{
+ rt_b->rt_period = ns_to_ktime(period);
+ rt_b->rt_runtime = runtime;
+
+ hrtimer_init(&rt_b->rt_period_timer,
+ CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ rt_b->rt_period_timer.function = sched_rt_period_timer;
+ rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+}
+
+static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+ ktime_t now;
+
+ if (rt_b->rt_runtime == RUNTIME_INF)
+ return;
+
+ if (hrtimer_active(&rt_b->rt_period_timer))
+ return;
+
+ spin_lock(&rt_b->rt_runtime_lock);
+ for (;;) {
+ if (hrtimer_active(&rt_b->rt_period_timer))
+ break;
+
+ now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
+ hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
+ hrtimer_start(&rt_b->rt_period_timer,
+ rt_b->rt_period_timer.expires,
+ HRTIMER_MODE_ABS);
+ }
+ spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+ hrtimer_cancel(&rt_b->rt_period_timer);
+}
+#endif
+