+
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
+static void __disable_runtime(struct rq *rq)
+{
+ struct root_domain *rd = rq->rd;
+ struct rt_rq *rt_rq;
+
+ if (unlikely(!scheduler_running))
+ return;
+
+ for_each_leaf_rt_rq(rt_rq, rq) {
+ struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+ s64 want;
+ int i;
+
+ raw_spin_lock(&rt_b->rt_runtime_lock);
+ raw_spin_lock(&rt_rq->rt_runtime_lock);
+ /*
+ * Either we're all inf and nobody needs to borrow, or we're
+ * already disabled and thus have nothing to do, or we have
+ * exactly the right amount of runtime to take out.
+ */
+ if (rt_rq->rt_runtime == RUNTIME_INF ||
+ rt_rq->rt_runtime == rt_b->rt_runtime)
+ goto balanced;
+ raw_spin_unlock(&rt_rq->rt_runtime_lock);
+
+ /*
+ * Calculate the difference between what we started out with
+ * and what we current have, that's the amount of runtime
+ * we lend and now have to reclaim.
+ */
+ want = rt_b->rt_runtime - rt_rq->rt_runtime;
+
+ /*
+ * Greedy reclaim, take back as much as we can.
+ */
+ for_each_cpu(i, rd->span) {
+ struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+ s64 diff;
+
+ /*
+ * Can't reclaim from ourselves or disabled runqueues.
+ */
+ if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
+ continue;
+
+ raw_spin_lock(&iter->rt_runtime_lock);
+ if (want > 0) {
+ diff = min_t(s64, iter->rt_runtime, want);
+ iter->rt_runtime -= diff;
+ want -= diff;
+ } else {
+ iter->rt_runtime -= want;
+ want -= want;
+ }
+ raw_spin_unlock(&iter->rt_runtime_lock);
+
+ if (!want)
+ break;
+ }
+
+ raw_spin_lock(&rt_rq->rt_runtime_lock);
+ /*
+ * We cannot be left wanting - that would mean some runtime
+ * leaked out of the system.
+ */
+ BUG_ON(want);
+balanced:
+ /*
+ * Disable all the borrow logic by pretending we have inf
+ * runtime - in which case borrowing doesn't make sense.
+ */
+ rt_rq->rt_runtime = RUNTIME_INF;
+ raw_spin_unlock(&rt_rq->rt_runtime_lock);
+ raw_spin_unlock(&rt_b->rt_runtime_lock);
+ }
+}
+
+static void disable_runtime(struct rq *rq)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ __disable_runtime(rq);
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static void __enable_runtime(struct rq *rq)
+{
+ struct rt_rq *rt_rq;
+
+ if (unlikely(!scheduler_running))
+ return;
+
+ /*
+ * Reset each runqueue's bandwidth settings
+ */
+ for_each_leaf_rt_rq(rt_rq, rq) {
+ struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+ raw_spin_lock(&rt_b->rt_runtime_lock);
+ raw_spin_lock(&rt_rq->rt_runtime_lock);
+ rt_rq->rt_runtime = rt_b->rt_runtime;
+ rt_rq->rt_time = 0;
+ rt_rq->rt_throttled = 0;
+ raw_spin_unlock(&rt_rq->rt_runtime_lock);
+ raw_spin_unlock(&rt_b->rt_runtime_lock);
+ }
+}
+
+static void enable_runtime(struct rq *rq)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ __enable_runtime(rq);
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static int balance_runtime(struct rt_rq *rt_rq)
+{
+ int more = 0;
+
+ if (rt_rq->rt_time > rt_rq->rt_runtime) {
+ raw_spin_unlock(&rt_rq->rt_runtime_lock);
+ more = do_balance_runtime(rt_rq);
+ raw_spin_lock(&rt_rq->rt_runtime_lock);
+ }
+
+ return more;
+}
+#else /* !CONFIG_SMP */
+static inline int balance_runtime(struct rt_rq *rt_rq)
+{
+ return 0;
+}
+#endif /* CONFIG_SMP */
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
+{
+ int i, idle = 1;
+ const struct cpumask *span;
+
+ if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
+ return 1;
+
+ span = sched_rt_period_mask();
+ for_each_cpu(i, span) {
+ int enqueue = 0;
+ struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
+ struct rq *rq = rq_of_rt_rq(rt_rq);
+
+ raw_spin_lock(&rq->lock);
+ if (rt_rq->rt_time) {
+ u64 runtime;
+
+ raw_spin_lock(&rt_rq->rt_runtime_lock);
+ if (rt_rq->rt_throttled)
+ balance_runtime(rt_rq);
+ runtime = rt_rq->rt_runtime;
+ rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
+ if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
+ rt_rq->rt_throttled = 0;
+ enqueue = 1;
+ }
+ if (rt_rq->rt_time || rt_rq->rt_nr_running)
+ idle = 0;
+ raw_spin_unlock(&rt_rq->rt_runtime_lock);
+ } else if (rt_rq->rt_nr_running)
+ idle = 0;
+
+ if (enqueue)
+ sched_rt_rq_enqueue(rt_rq);
+ raw_spin_unlock(&rq->lock);
+ }
+
+ return idle;
+}