Revert "sched: Throttle qos cfs_rq when current cpu is running online task"

This reverts commit a10c09df.

kernel/sched/core.c

@@ -6975,10 +6975,8 @@ static int cpu_qos_write(struct cgroup_subsys_state *css,
 
 	if (qos_level == -1) {
 		policy = SCHED_IDLE;
-		cfs_bandwidth_usage_inc();
 	} else {
 		policy = SCHED_NORMAL;
-		cfs_bandwidth_usage_dec();
 	}
 
 	tg->qos_level = qos_level;

kernel/sched/fair.c

@@ -99,10 +99,6 @@ int __weak arch_asym_cpu_priority(int cpu)
 }
 #endif
 
-#ifdef CONFIG_QOS_SCHED
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct list_head, qos_throttled_cfs_rq);
-#endif
-
 #ifdef CONFIG_CFS_BANDWIDTH
 /*
  * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
@@ -6873,128 +6869,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 		set_last_buddy(se);
 }
 
-#ifdef CONFIG_QOS_SCHED
-static void throttle_qos_cfs_rq(struct cfs_rq *cfs_rq)
-{
-	struct rq *rq = rq_of(cfs_rq);
-	struct sched_entity *se;
-	long task_delta, idle_task_delta, dequeue = 1;
-
-	se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
-
-	/* freeze hierarchy runnable averages while throttled */
-	rcu_read_lock();
-	walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
-	rcu_read_unlock();
-
-	task_delta = cfs_rq->h_nr_running;
-	idle_task_delta = cfs_rq->idle_h_nr_running;
-	for_each_sched_entity(se) {
-		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
-		/* throttled entity or throttle-on-deactivate */
-		if (!se->on_rq)
-			break;
-
-		if (dequeue)
-			dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
-		qcfs_rq->h_nr_running -= task_delta;
-		qcfs_rq->idle_h_nr_running -= idle_task_delta;
-
-		if (qcfs_rq->load.weight)
-			dequeue = 0;
-	}
-
-	if (!se) {
-		sub_nr_running(rq, task_delta);
-	}
-
-	cfs_rq->throttled = 1;
-	cfs_rq->throttled_clock = rq_clock(rq);
-
-	list_add(&cfs_rq->throttled_list, &per_cpu(qos_throttled_cfs_rq, cpu_of(rq)));
-}
-
-static void unthrottle_qos_cfs_rq(struct cfs_rq *cfs_rq)
-{
-	struct rq *rq = rq_of(cfs_rq);
-	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
-	struct sched_entity *se;
-	int enqueue = 1;
-	long task_delta, idle_task_delta;
-
-	se = cfs_rq->tg->se[cpu_of(rq)];
-
-	cfs_rq->throttled = 0;
-
-	update_rq_clock(rq);
-
-	cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock;
-	list_del_init(&cfs_rq->throttled_list);
-
-	/* update hierarchical throttle state */
-	walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
-
-	if (!cfs_rq->load.weight)
-		return;
-
-	task_delta = cfs_rq->h_nr_running;
-	idle_task_delta = cfs_rq->idle_h_nr_running;
-	for_each_sched_entity(se) {
-		if (se->on_rq)
-			enqueue = 0;
-
-		cfs_rq = cfs_rq_of(se);
-		if (enqueue)
-			enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
-		cfs_rq->h_nr_running += task_delta;
-		cfs_rq->idle_h_nr_running += idle_task_delta;
-
-		if (cfs_rq_throttled(cfs_rq))
-			break;
-	}
-
-	assert_list_leaf_cfs_rq(rq);
-
-	if (!se) {
-		add_nr_running(rq, task_delta);
-	}
-
-	/* Determine whether we need to wake up potentially idle CPU: */
-	if (rq->curr == rq->idle && rq->cfs.nr_running)
-		resched_curr(rq);
-}
-
-static int unthrottle_qos_cfs_rqs(int cpu)
-{
-	struct cfs_rq *cfs_rq, *tmp_rq;
-	int res = 0;
-
-	list_for_each_entry_safe(cfs_rq, tmp_rq, &per_cpu(qos_throttled_cfs_rq, cpu),
-				throttled_list) {
-		if (cfs_rq_throttled(cfs_rq)) {
-			unthrottle_qos_cfs_rq(cfs_rq);
-			res++;
-		}
-	}
-
-	return res;
-}
-
-static bool check_qos_cfs_rq(struct cfs_rq *cfs_rq)
-{
-	if (!cfs_bandwidth_used())
-		return false;
-
-	if (cfs_rq && cfs_rq->tg->qos_level < 0 &&
-	    !sched_idle_cpu(cpu_of(rq_of(cfs_rq)))) {
-		throttle_qos_cfs_rq(cfs_rq);
-		return true;
-	}
-
-	return false;
-}
-#endif
-
 static struct task_struct *
 pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 {
@@ -7053,12 +6927,6 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf
 
 		se = pick_next_entity(cfs_rq, curr);
 		cfs_rq = group_cfs_rq(se);
-#ifdef CONFIG_QOS_SCHED
-		if (check_qos_cfs_rq(cfs_rq)) {
-			cfs_rq = &rq->cfs;
-			BUG_ON(cfs_rq->nr_running == 0);
-		}
-#endif
 	} while (cfs_rq);
 
 	p = task_of(se);
@@ -7148,12 +7016,6 @@ done: __maybe_unused;
 	if (new_tasks > 0)
 		goto again;
 
-#ifdef CONFIG_QOS_SCHED
-	if (unthrottle_qos_cfs_rqs(cpu_of(rq))) {
-		goto again;
-	}
-#endif
-
 	return NULL;
 }
 
@@ -10821,14 +10683,6 @@ void show_numa_stats(struct task_struct *p, struct seq_file *m)
 
 __init void init_sched_fair_class(void)
 {
-#ifdef CONFIG_QOS_SCHED
-	int i;
-
-	for_each_possible_cpu(i) {
-		INIT_LIST_HEAD(&per_cpu(qos_throttled_cfs_rq, i));
-	}
-#endif
-
 #ifdef CONFIG_SMP
 	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);