sched: rt-group: synchonised bandwidth period
Various SMP balancing algorithms require that the bandwidth period
run in sync.
Possible improvements are moving the rt_bandwidth thing into root_domain
and keeping a span per rt_bandwidth which marks throttled cpus.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 0a6d2e5..8bc1761 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -62,7 +62,7 @@
if (!rt_rq->tg)
return RUNTIME_INF;
- return rt_rq->tg->rt_runtime;
+ return rt_rq->tg->rt_bandwidth.rt_runtime;
}
#define for_each_leaf_rt_rq(rt_rq, rq) \
@@ -127,14 +127,29 @@
return p->prio != p->normal_prio;
}
+#ifdef CONFIG_SMP
+static inline cpumask_t sched_rt_period_mask(void)
+{
+ return cpu_rq(smp_processor_id())->rd->span;
+}
+#else
+static inline cpumask_t sched_rt_period_mask(void)
+{
+ return cpu_online_map;
+}
+#endif
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+ return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
+}
+
#else
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
- if (sysctl_sched_rt_runtime == -1)
- return RUNTIME_INF;
-
- return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
+ return def_rt_bandwidth.rt_runtime;
}
#define for_each_leaf_rt_rq(rt_rq, rq) \
@@ -173,8 +188,55 @@
{
return rt_rq->rt_throttled;
}
+
+static inline cpumask_t sched_rt_period_mask(void)
+{
+ return cpu_online_map;
+}
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+ return &cpu_rq(cpu)->rt;
+}
+
#endif
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
+{
+ int i, idle = 1;
+ cpumask_t span;
+
+ if (rt_b->rt_runtime == RUNTIME_INF)
+ return 1;
+
+ span = sched_rt_period_mask();
+ for_each_cpu_mask(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);
+
+ spin_lock(&rq->lock);
+ if (rt_rq->rt_time) {
+ u64 runtime = rt_b->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;
+ }
+
+ if (enqueue)
+ sched_rt_rq_enqueue(rt_rq);
+ spin_unlock(&rq->lock);
+ }
+
+ return idle;
+}
+
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_RT_GROUP_SCHED
@@ -198,11 +260,7 @@
return rt_rq_throttled(rt_rq);
if (rt_rq->rt_time > runtime) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
-
- rq->rt_throttled = 1;
rt_rq->rt_throttled = 1;
-
if (rt_rq_throttled(rt_rq)) {
sched_rt_rq_dequeue(rt_rq);
return 1;
@@ -212,29 +270,6 @@
return 0;
}
-static void update_sched_rt_period(struct rq *rq)
-{
- struct rt_rq *rt_rq;
- u64 period;
-
- while (rq->clock > rq->rt_period_expire) {
- period = (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
- rq->rt_period_expire += period;
-
- for_each_leaf_rt_rq(rt_rq, rq) {
- u64 runtime = sched_rt_runtime(rt_rq);
-
- rt_rq->rt_time -= min(rt_rq->rt_time, runtime);
- if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
- rt_rq->rt_throttled = 0;
- sched_rt_rq_enqueue(rt_rq);
- }
- }
-
- rq->rt_throttled = 0;
- }
-}
-
/*
* Update the current task's runtime statistics. Skip current tasks that
* are not in our scheduling class.
@@ -284,6 +319,11 @@
#ifdef CONFIG_RT_GROUP_SCHED
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted++;
+
+ if (rt_rq->tg)
+ start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
+#else
+ start_rt_bandwidth(&def_rt_bandwidth);
#endif
}