diff options
Diffstat (limited to 'kernel/sched/rt.c')
| -rw-r--r-- | kernel/sched/rt.c | 109 |
1 files changed, 105 insertions, 4 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 8ec86abe0ea1..541b8494450e 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -8,6 +8,8 @@ #include <linux/slab.h> #include <linux/irq_work.h> +#include "walt.h" + int sched_rr_timeslice = RR_TIMESLICE; static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun); @@ -889,6 +891,51 @@ static inline int rt_se_prio(struct sched_rt_entity *rt_se) return rt_task_of(rt_se)->prio; } +static void dump_throttled_rt_tasks(struct rt_rq *rt_rq) +{ + struct rt_prio_array *array = &rt_rq->active; + struct sched_rt_entity *rt_se; + char buf[500]; + char *pos = buf; + char *end = buf + sizeof(buf); + int idx; + + pos += snprintf(pos, sizeof(buf), + "sched: RT throttling activated for rt_rq %p (cpu %d)\n", + rt_rq, cpu_of(rq_of_rt_rq(rt_rq))); + + if (bitmap_empty(array->bitmap, MAX_RT_PRIO)) + goto out; + + pos += snprintf(pos, end - pos, "potential CPU hogs:\n"); + idx = sched_find_first_bit(array->bitmap); + while (idx < MAX_RT_PRIO) { + list_for_each_entry(rt_se, array->queue + idx, run_list) { + struct task_struct *p; + + if (!rt_entity_is_task(rt_se)) + continue; + + p = rt_task_of(rt_se); + if (pos < end) + pos += snprintf(pos, end - pos, "\t%s (%d)\n", + p->comm, p->pid); + } + idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx + 1); + } +out: +#ifdef CONFIG_PANIC_ON_RT_THROTTLING + /* + * Use pr_err() in the BUG() case since printk_sched() will + * not get flushed and deadlock is not a concern. + */ + pr_err("%s", buf); + BUG(); +#else + printk_deferred("%s", buf); +#endif +} + static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) { u64 runtime = sched_rt_runtime(rt_rq); @@ -912,8 +959,14 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) * but accrue some time due to boosting. */ if (likely(rt_b->rt_runtime)) { + static bool once = false; + rt_rq->rt_throttled = 1; - printk_deferred_once("sched: RT throttling activated\n"); + + if (!once) { + once = true; + dump_throttled_rt_tasks(rt_rq); + } } else { /* * In case we did anyway, make it go away, @@ -1261,6 +1314,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags) rt_se->timeout = 0; enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD); + walt_inc_cumulative_runnable_avg(rq, p); if (!task_current(rq, p) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); @@ -1272,6 +1326,7 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags) update_curr_rt(rq); dequeue_rt_entity(rt_se); + walt_dec_cumulative_runnable_avg(rq, p); dequeue_pushable_task(rq, p); } @@ -1426,6 +1481,41 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag #endif } +#ifdef CONFIG_SMP +static void sched_rt_update_capacity_req(struct rq *rq) +{ + u64 total, used, age_stamp, avg; + s64 delta; + + if (!sched_freq()) + return; + + sched_avg_update(rq); + /* + * Since we're reading these variables without serialization make sure + * we read them once before doing sanity checks on them. + */ + age_stamp = READ_ONCE(rq->age_stamp); + avg = READ_ONCE(rq->rt_avg); + delta = rq_clock(rq) - age_stamp; + + if (unlikely(delta < 0)) + delta = 0; + + total = sched_avg_period() + delta; + + used = div_u64(avg, total); + if (unlikely(used > SCHED_CAPACITY_SCALE)) + used = SCHED_CAPACITY_SCALE; + + set_rt_cpu_capacity(rq->cpu, 1, (unsigned long)(used)); +} +#else +static inline void sched_rt_update_capacity_req(struct rq *rq) +{ } + +#endif + static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, struct rt_rq *rt_rq) { @@ -1494,8 +1584,17 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev) if (prev->sched_class == &rt_sched_class) update_curr_rt(rq); - if (!rt_rq->rt_queued) + if (!rt_rq->rt_queued) { + /* + * The next task to be picked on this rq will have a lower + * priority than rt tasks so we can spend some time to update + * the capacity used by rt tasks based on the last activity. + * This value will be the used as an estimation of the next + * activity. + */ + sched_rt_update_capacity_req(rq); return NULL; + } put_prev_task(rq, prev); @@ -2136,10 +2235,9 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p) #ifdef CONFIG_SMP if (p->nr_cpus_allowed > 1 && rq->rt.overloaded) queue_push_tasks(rq); -#else +#endif /* CONFIG_SMP */ if (p->prio < rq->curr->prio) resched_curr(rq); -#endif /* CONFIG_SMP */ } } @@ -2212,6 +2310,9 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) update_curr_rt(rq); + if (rq->rt.rt_nr_running) + sched_rt_update_capacity_req(rq); + watchdog(rq, p); /* |