1/*
   2 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
   3 * policies)
   4 */
   5
   6#include "sched.h"
   7
   8#include <linux/slab.h>
   9
  10static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
  11
  12struct rt_bandwidth def_rt_bandwidth;
  13
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  14static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
  15{
  16	struct rt_bandwidth *rt_b =
  17		container_of(timer, struct rt_bandwidth, rt_period_timer);
  18	ktime_t now;
  19	int overrun;
  20	int idle = 0;
 
  21
 
  22	for (;;) {
  23		now = hrtimer_cb_get_time(timer);
  24		overrun = hrtimer_forward(timer, now, rt_b->rt_period);
  25
  26		if (!overrun)
  27			break;
  28
 
  29		idle = do_sched_rt_period_timer(rt_b, overrun);
 
  30	}
 
 
 
  31
  32	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
  33}
  34
  35void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
  36{
  37	rt_b->rt_period = ns_to_ktime(period);
  38	rt_b->rt_runtime = runtime;
  39
  40	raw_spin_lock_init(&rt_b->rt_runtime_lock);
  41
  42	hrtimer_init(&rt_b->rt_period_timer,
  43			CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  44	rt_b->rt_period_timer.function = sched_rt_period_timer;
  45}
  46
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  47static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
  48{
  49	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
  50		return;
  51
  52	if (hrtimer_active(&rt_b->rt_period_timer))
  53		return;
  54
  55	raw_spin_lock(&rt_b->rt_runtime_lock);
  56	start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period);
  57	raw_spin_unlock(&rt_b->rt_runtime_lock);
  58}
  59
  60void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
  61{
  62	struct rt_prio_array *array;
  63	int i;
  64
  65	array = &rt_rq->active;
  66	for (i = 0; i < MAX_RT_PRIO; i++) {
  67		INIT_LIST_HEAD(array->queue + i);
  68		__clear_bit(i, array->bitmap);
  69	}
  70	/* delimiter for bitsearch: */
  71	__set_bit(MAX_RT_PRIO, array->bitmap);
  72
  73#if defined CONFIG_SMP
  74	rt_rq->highest_prio.curr = MAX_RT_PRIO;
  75	rt_rq->highest_prio.next = MAX_RT_PRIO;
  76	rt_rq->rt_nr_migratory = 0;
  77	rt_rq->overloaded = 0;
  78	plist_head_init(&rt_rq->pushable_tasks);
  79#endif
 
 
  80
  81	rt_rq->rt_time = 0;
  82	rt_rq->rt_throttled = 0;
  83	rt_rq->rt_runtime = 0;
  84	raw_spin_lock_init(&rt_rq->rt_runtime_lock);
  85}
  86
  87#ifdef CONFIG_RT_GROUP_SCHED
  88static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
  89{
  90	hrtimer_cancel(&rt_b->rt_period_timer);
  91}
  92
  93#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
  94
  95static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
  96{
  97#ifdef CONFIG_SCHED_DEBUG
  98	WARN_ON_ONCE(!rt_entity_is_task(rt_se));
  99#endif
 100	return container_of(rt_se, struct task_struct, rt);
 101}
 102
 103static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
 104{
 105	return rt_rq->rq;
 106}
 107
 108static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
 109{
 110	return rt_se->rt_rq;
 111}
 112
 113void free_rt_sched_group(struct task_group *tg)
 114{
 115	int i;
 
 
 
 116
 
 
 117	if (tg->rt_se)
 118		destroy_rt_bandwidth(&tg->rt_bandwidth);
 119
 
 
 
 
 
 
 120	for_each_possible_cpu(i) {
 121		if (tg->rt_rq)
 122			kfree(tg->rt_rq[i]);
 123		if (tg->rt_se)
 124			kfree(tg->rt_se[i]);
 125	}
 126
 127	kfree(tg->rt_rq);
 128	kfree(tg->rt_se);
 129}
 130
 131void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
 132		struct sched_rt_entity *rt_se, int cpu,
 133		struct sched_rt_entity *parent)
 134{
 135	struct rq *rq = cpu_rq(cpu);
 136
 137	rt_rq->highest_prio.curr = MAX_RT_PRIO;
 138	rt_rq->rt_nr_boosted = 0;
 139	rt_rq->rq = rq;
 140	rt_rq->tg = tg;
 141
 142	tg->rt_rq[cpu] = rt_rq;
 143	tg->rt_se[cpu] = rt_se;
 144
 145	if (!rt_se)
 146		return;
 147
 148	if (!parent)
 149		rt_se->rt_rq = &rq->rt;
 150	else
 151		rt_se->rt_rq = parent->my_q;
 152
 153	rt_se->my_q = rt_rq;
 154	rt_se->parent = parent;
 155	INIT_LIST_HEAD(&rt_se->run_list);
 156}
 157
 158int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 159{
 160	struct rt_rq *rt_rq;
 161	struct sched_rt_entity *rt_se;
 162	int i;
 163
 164	tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
 165	if (!tg->rt_rq)
 166		goto err;
 167	tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
 168	if (!tg->rt_se)
 169		goto err;
 170
 171	init_rt_bandwidth(&tg->rt_bandwidth,
 172			ktime_to_ns(def_rt_bandwidth.rt_period), 0);
 173
 174	for_each_possible_cpu(i) {
 175		rt_rq = kzalloc_node(sizeof(struct rt_rq),
 176				     GFP_KERNEL, cpu_to_node(i));
 177		if (!rt_rq)
 178			goto err;
 179
 180		rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
 181				     GFP_KERNEL, cpu_to_node(i));
 182		if (!rt_se)
 183			goto err_free_rq;
 184
 185		init_rt_rq(rt_rq, cpu_rq(i));
 186		rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
 187		init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
 188	}
 189
 190	return 1;
 191
 192err_free_rq:
 193	kfree(rt_rq);
 194err:
 195	return 0;
 196}
 197
 198#else /* CONFIG_RT_GROUP_SCHED */
 199
 200#define rt_entity_is_task(rt_se) (1)
 201
 202static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
 203{
 204	return container_of(rt_se, struct task_struct, rt);
 205}
 206
 207static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
 208{
 209	return container_of(rt_rq, struct rq, rt);
 210}
 211
 212static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
 213{
 214	struct task_struct *p = rt_task_of(rt_se);
 215	struct rq *rq = task_rq(p);
 
 
 
 
 
 
 216
 217	return &rq->rt;
 218}
 219
 
 
 220void free_rt_sched_group(struct task_group *tg) { }
 221
 222int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 223{
 224	return 1;
 225}
 226#endif /* CONFIG_RT_GROUP_SCHED */
 227
 228#ifdef CONFIG_SMP
 229
 
 
 
 
 
 
 230static inline int rt_overloaded(struct rq *rq)
 231{
 232	return atomic_read(&rq->rd->rto_count);
 233}
 234
 235static inline void rt_set_overload(struct rq *rq)
 236{
 237	if (!rq->online)
 238		return;
 239
 240	cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
 241	/*
 242	 * Make sure the mask is visible before we set
 243	 * the overload count. That is checked to determine
 244	 * if we should look at the mask. It would be a shame
 245	 * if we looked at the mask, but the mask was not
 246	 * updated yet.
 
 
 247	 */
 248	wmb();
 249	atomic_inc(&rq->rd->rto_count);
 250}
 251
 252static inline void rt_clear_overload(struct rq *rq)
 253{
 254	if (!rq->online)
 255		return;
 256
 257	/* the order here really doesn't matter */
 258	atomic_dec(&rq->rd->rto_count);
 259	cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
 260}
 261
 262static void update_rt_migration(struct rt_rq *rt_rq)
 263{
 264	if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
 265		if (!rt_rq->overloaded) {
 266			rt_set_overload(rq_of_rt_rq(rt_rq));
 267			rt_rq->overloaded = 1;
 268		}
 269	} else if (rt_rq->overloaded) {
 270		rt_clear_overload(rq_of_rt_rq(rt_rq));
 271		rt_rq->overloaded = 0;
 272	}
 273}
 274
 275static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 276{
 277	struct task_struct *p;
 278
 279	if (!rt_entity_is_task(rt_se))
 280		return;
 281
 282	p = rt_task_of(rt_se);
 283	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
 284
 285	rt_rq->rt_nr_total++;
 286	if (p->nr_cpus_allowed > 1)
 287		rt_rq->rt_nr_migratory++;
 288
 289	update_rt_migration(rt_rq);
 290}
 291
 292static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 293{
 294	struct task_struct *p;
 295
 296	if (!rt_entity_is_task(rt_se))
 297		return;
 298
 299	p = rt_task_of(rt_se);
 300	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
 301
 302	rt_rq->rt_nr_total--;
 303	if (p->nr_cpus_allowed > 1)
 304		rt_rq->rt_nr_migratory--;
 305
 306	update_rt_migration(rt_rq);
 307}
 308
 309static inline int has_pushable_tasks(struct rq *rq)
 310{
 311	return !plist_head_empty(&rq->rt.pushable_tasks);
 312}
 313
 314static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
 315{
 316	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
 317	plist_node_init(&p->pushable_tasks, p->prio);
 318	plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
 319
 320	/* Update the highest prio pushable task */
 321	if (p->prio < rq->rt.highest_prio.next)
 322		rq->rt.highest_prio.next = p->prio;
 
 
 
 
 
 323}
 324
 325static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
 326{
 327	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
 328
 329	/* Update the new highest prio pushable task */
 330	if (has_pushable_tasks(rq)) {
 331		p = plist_first_entry(&rq->rt.pushable_tasks,
 332				      struct task_struct, pushable_tasks);
 333		rq->rt.highest_prio.next = p->prio;
 334	} else
 335		rq->rt.highest_prio.next = MAX_RT_PRIO;
 
 
 
 
 
 
 336}
 337
 338#else
 339
 340static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
 341{
 342}
 343
 344static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
 345{
 346}
 347
 348static inline
 349void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 350{
 351}
 
 352
 353static inline
 354void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 
 
 355{
 
 356}
 357
 358#endif /* CONFIG_SMP */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 359
 360static inline int on_rt_rq(struct sched_rt_entity *rt_se)
 
 
 
 
 
 
 
 
 
 
 
 
 361{
 362	return !list_empty(&rt_se->run_list);
 363}
 
 364
 365#ifdef CONFIG_RT_GROUP_SCHED
 366
 367static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
 368{
 369	if (!rt_rq->tg)
 370		return RUNTIME_INF;
 371
 372	return rt_rq->rt_runtime;
 373}
 374
 375static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 376{
 377	return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
 378}
 379
 380typedef struct task_group *rt_rq_iter_t;
 381
 382static inline struct task_group *next_task_group(struct task_group *tg)
 383{
 384	do {
 385		tg = list_entry_rcu(tg->list.next,
 386			typeof(struct task_group), list);
 387	} while (&tg->list != &task_groups && task_group_is_autogroup(tg));
 388
 389	if (&tg->list == &task_groups)
 390		tg = NULL;
 391
 392	return tg;
 393}
 394
 395#define for_each_rt_rq(rt_rq, iter, rq)					\
 396	for (iter = container_of(&task_groups, typeof(*iter), list);	\
 397		(iter = next_task_group(iter)) &&			\
 398		(rt_rq = iter->rt_rq[cpu_of(rq)]);)
 399
 400static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
 401{
 402	list_add_rcu(&rt_rq->leaf_rt_rq_list,
 403			&rq_of_rt_rq(rt_rq)->leaf_rt_rq_list);
 404}
 405
 406static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
 407{
 408	list_del_rcu(&rt_rq->leaf_rt_rq_list);
 409}
 410
 411#define for_each_leaf_rt_rq(rt_rq, rq) \
 412	list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
 413
 414#define for_each_sched_rt_entity(rt_se) \
 415	for (; rt_se; rt_se = rt_se->parent)
 416
 417static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
 418{
 419	return rt_se->my_q;
 420}
 421
 422static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head);
 423static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
 424
 425static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 426{
 427	struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
 
 428	struct sched_rt_entity *rt_se;
 429
 430	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
 431
 432	rt_se = rt_rq->tg->rt_se[cpu];
 433
 434	if (rt_rq->rt_nr_running) {
 435		if (rt_se && !on_rt_rq(rt_se))
 436			enqueue_rt_entity(rt_se, false);
 
 
 
 437		if (rt_rq->highest_prio.curr < curr->prio)
 438			resched_task(curr);
 439	}
 440}
 441
 442static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 443{
 444	struct sched_rt_entity *rt_se;
 445	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
 446
 447	rt_se = rt_rq->tg->rt_se[cpu];
 448
 449	if (rt_se && on_rt_rq(rt_se))
 450		dequeue_rt_entity(rt_se);
 
 
 
 
 
 451}
 452
 453static inline int rt_rq_throttled(struct rt_rq *rt_rq)
 454{
 455	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
 456}
 457
 458static int rt_se_boosted(struct sched_rt_entity *rt_se)
 459{
 460	struct rt_rq *rt_rq = group_rt_rq(rt_se);
 461	struct task_struct *p;
 462
 463	if (rt_rq)
 464		return !!rt_rq->rt_nr_boosted;
 465
 466	p = rt_task_of(rt_se);
 467	return p->prio != p->normal_prio;
 468}
 469
 470#ifdef CONFIG_SMP
 471static inline const struct cpumask *sched_rt_period_mask(void)
 472{
 473	return cpu_rq(smp_processor_id())->rd->span;
 474}
 475#else
 476static inline const struct cpumask *sched_rt_period_mask(void)
 477{
 478	return cpu_online_mask;
 479}
 480#endif
 481
 482static inline
 483struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
 484{
 485	return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
 486}
 487
 488static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
 489{
 490	return &rt_rq->tg->rt_bandwidth;
 491}
 492
 493#else /* !CONFIG_RT_GROUP_SCHED */
 494
 495static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
 496{
 497	return rt_rq->rt_runtime;
 498}
 499
 500static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 501{
 502	return ktime_to_ns(def_rt_bandwidth.rt_period);
 503}
 504
 505typedef struct rt_rq *rt_rq_iter_t;
 506
 507#define for_each_rt_rq(rt_rq, iter, rq) \
 508	for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
 509
 510static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
 511{
 512}
 513
 514static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
 515{
 516}
 517
 518#define for_each_leaf_rt_rq(rt_rq, rq) \
 519	for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
 520
 521#define for_each_sched_rt_entity(rt_se) \
 522	for (; rt_se; rt_se = NULL)
 523
 524static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
 525{
 526	return NULL;
 527}
 528
 529static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 530{
 531	if (rt_rq->rt_nr_running)
 532		resched_task(rq_of_rt_rq(rt_rq)->curr);
 
 
 
 
 
 533}
 534
 535static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 536{
 
 537}
 538
 539static inline int rt_rq_throttled(struct rt_rq *rt_rq)
 540{
 541	return rt_rq->rt_throttled;
 542}
 543
 544static inline const struct cpumask *sched_rt_period_mask(void)
 545{
 546	return cpu_online_mask;
 547}
 548
 549static inline
 550struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
 551{
 552	return &cpu_rq(cpu)->rt;
 553}
 554
 555static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
 556{
 557	return &def_rt_bandwidth;
 558}
 559
 560#endif /* CONFIG_RT_GROUP_SCHED */
 561
 
 
 
 
 
 
 
 
 562#ifdef CONFIG_SMP
 563/*
 564 * We ran out of runtime, see if we can borrow some from our neighbours.
 565 */
 566static int do_balance_runtime(struct rt_rq *rt_rq)
 567{
 568	struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
 569	struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
 570	int i, weight, more = 0;
 571	u64 rt_period;
 572
 573	weight = cpumask_weight(rd->span);
 574
 575	raw_spin_lock(&rt_b->rt_runtime_lock);
 576	rt_period = ktime_to_ns(rt_b->rt_period);
 577	for_each_cpu(i, rd->span) {
 578		struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
 579		s64 diff;
 580
 581		if (iter == rt_rq)
 582			continue;
 583
 584		raw_spin_lock(&iter->rt_runtime_lock);
 585		/*
 586		 * Either all rqs have inf runtime and there's nothing to steal
 587		 * or __disable_runtime() below sets a specific rq to inf to
 588		 * indicate its been disabled and disalow stealing.
 589		 */
 590		if (iter->rt_runtime == RUNTIME_INF)
 591			goto next;
 592
 593		/*
 594		 * From runqueues with spare time, take 1/n part of their
 595		 * spare time, but no more than our period.
 596		 */
 597		diff = iter->rt_runtime - iter->rt_time;
 598		if (diff > 0) {
 599			diff = div_u64((u64)diff, weight);
 600			if (rt_rq->rt_runtime + diff > rt_period)
 601				diff = rt_period - rt_rq->rt_runtime;
 602			iter->rt_runtime -= diff;
 603			rt_rq->rt_runtime += diff;
 604			more = 1;
 605			if (rt_rq->rt_runtime == rt_period) {
 606				raw_spin_unlock(&iter->rt_runtime_lock);
 607				break;
 608			}
 609		}
 610next:
 611		raw_spin_unlock(&iter->rt_runtime_lock);
 612	}
 613	raw_spin_unlock(&rt_b->rt_runtime_lock);
 614
 615	return more;
 616}
 617
 618/*
 619 * Ensure this RQ takes back all the runtime it lend to its neighbours.
 620 */
 621static void __disable_runtime(struct rq *rq)
 622{
 623	struct root_domain *rd = rq->rd;
 624	rt_rq_iter_t iter;
 625	struct rt_rq *rt_rq;
 626
 627	if (unlikely(!scheduler_running))
 628		return;
 629
 630	for_each_rt_rq(rt_rq, iter, rq) {
 631		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
 632		s64 want;
 633		int i;
 634
 635		raw_spin_lock(&rt_b->rt_runtime_lock);
 636		raw_spin_lock(&rt_rq->rt_runtime_lock);
 637		/*
 638		 * Either we're all inf and nobody needs to borrow, or we're
 639		 * already disabled and thus have nothing to do, or we have
 640		 * exactly the right amount of runtime to take out.
 641		 */
 642		if (rt_rq->rt_runtime == RUNTIME_INF ||
 643				rt_rq->rt_runtime == rt_b->rt_runtime)
 644			goto balanced;
 645		raw_spin_unlock(&rt_rq->rt_runtime_lock);
 646
 647		/*
 648		 * Calculate the difference between what we started out with
 649		 * and what we current have, that's the amount of runtime
 650		 * we lend and now have to reclaim.
 651		 */
 652		want = rt_b->rt_runtime - rt_rq->rt_runtime;
 653
 654		/*
 655		 * Greedy reclaim, take back as much as we can.
 656		 */
 657		for_each_cpu(i, rd->span) {
 658			struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
 659			s64 diff;
 660
 661			/*
 662			 * Can't reclaim from ourselves or disabled runqueues.
 663			 */
 664			if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
 665				continue;
 666
 667			raw_spin_lock(&iter->rt_runtime_lock);
 668			if (want > 0) {
 669				diff = min_t(s64, iter->rt_runtime, want);
 670				iter->rt_runtime -= diff;
 671				want -= diff;
 672			} else {
 673				iter->rt_runtime -= want;
 674				want -= want;
 675			}
 676			raw_spin_unlock(&iter->rt_runtime_lock);
 677
 678			if (!want)
 679				break;
 680		}
 681
 682		raw_spin_lock(&rt_rq->rt_runtime_lock);
 683		/*
 684		 * We cannot be left wanting - that would mean some runtime
 685		 * leaked out of the system.
 686		 */
 687		BUG_ON(want);
 688balanced:
 689		/*
 690		 * Disable all the borrow logic by pretending we have inf
 691		 * runtime - in which case borrowing doesn't make sense.
 692		 */
 693		rt_rq->rt_runtime = RUNTIME_INF;
 
 694		raw_spin_unlock(&rt_rq->rt_runtime_lock);
 695		raw_spin_unlock(&rt_b->rt_runtime_lock);
 696	}
 697}
 698
 699static void disable_runtime(struct rq *rq)
 700{
 701	unsigned long flags;
 702
 703	raw_spin_lock_irqsave(&rq->lock, flags);
 704	__disable_runtime(rq);
 705	raw_spin_unlock_irqrestore(&rq->lock, flags);
 706}
 707
 708static void __enable_runtime(struct rq *rq)
 709{
 710	rt_rq_iter_t iter;
 711	struct rt_rq *rt_rq;
 712
 713	if (unlikely(!scheduler_running))
 714		return;
 715
 716	/*
 717	 * Reset each runqueue's bandwidth settings
 718	 */
 719	for_each_rt_rq(rt_rq, iter, rq) {
 720		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
 721
 722		raw_spin_lock(&rt_b->rt_runtime_lock);
 723		raw_spin_lock(&rt_rq->rt_runtime_lock);
 724		rt_rq->rt_runtime = rt_b->rt_runtime;
 725		rt_rq->rt_time = 0;
 726		rt_rq->rt_throttled = 0;
 727		raw_spin_unlock(&rt_rq->rt_runtime_lock);
 728		raw_spin_unlock(&rt_b->rt_runtime_lock);
 729	}
 730}
 731
 732static void enable_runtime(struct rq *rq)
 733{
 734	unsigned long flags;
 735
 736	raw_spin_lock_irqsave(&rq->lock, flags);
 737	__enable_runtime(rq);
 738	raw_spin_unlock_irqrestore(&rq->lock, flags);
 739}
 740
 741int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
 742{
 743	int cpu = (int)(long)hcpu;
 744
 745	switch (action) {
 746	case CPU_DOWN_PREPARE:
 747	case CPU_DOWN_PREPARE_FROZEN:
 748		disable_runtime(cpu_rq(cpu));
 749		return NOTIFY_OK;
 750
 751	case CPU_DOWN_FAILED:
 752	case CPU_DOWN_FAILED_FROZEN:
 753	case CPU_ONLINE:
 754	case CPU_ONLINE_FROZEN:
 755		enable_runtime(cpu_rq(cpu));
 756		return NOTIFY_OK;
 757
 758	default:
 759		return NOTIFY_DONE;
 760	}
 761}
 762
 763static int balance_runtime(struct rt_rq *rt_rq)
 764{
 765	int more = 0;
 766
 767	if (!sched_feat(RT_RUNTIME_SHARE))
 768		return more;
 769
 770	if (rt_rq->rt_time > rt_rq->rt_runtime) {
 771		raw_spin_unlock(&rt_rq->rt_runtime_lock);
 772		more = do_balance_runtime(rt_rq);
 773		raw_spin_lock(&rt_rq->rt_runtime_lock);
 774	}
 775
 776	return more;
 777}
 778#else /* !CONFIG_SMP */
 779static inline int balance_runtime(struct rt_rq *rt_rq)
 780{
 781	return 0;
 782}
 783#endif /* CONFIG_SMP */
 784
 785static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 786{
 787	int i, idle = 1, throttled = 0;
 788	const struct cpumask *span;
 789
 790	span = sched_rt_period_mask();
 
 
 
 
 
 
 
 
 
 
 
 
 
 791	for_each_cpu(i, span) {
 792		int enqueue = 0;
 793		struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
 794		struct rq *rq = rq_of_rt_rq(rt_rq);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 795
 796		raw_spin_lock(&rq->lock);
 797		if (rt_rq->rt_time) {
 798			u64 runtime;
 799
 800			raw_spin_lock(&rt_rq->rt_runtime_lock);
 801			if (rt_rq->rt_throttled)
 802				balance_runtime(rt_rq);
 803			runtime = rt_rq->rt_runtime;
 804			rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
 805			if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
 806				rt_rq->rt_throttled = 0;
 807				enqueue = 1;
 808
 809				/*
 810				 * Force a clock update if the CPU was idle,
 811				 * lest wakeup -> unthrottle time accumulate.
 
 
 
 812				 */
 813				if (rt_rq->rt_nr_running && rq->curr == rq->idle)
 814					rq->skip_clock_update = -1;
 815			}
 816			if (rt_rq->rt_time || rt_rq->rt_nr_running)
 817				idle = 0;
 818			raw_spin_unlock(&rt_rq->rt_runtime_lock);
 819		} else if (rt_rq->rt_nr_running) {
 820			idle = 0;
 821			if (!rt_rq_throttled(rt_rq))
 822				enqueue = 1;
 823		}
 824		if (rt_rq->rt_throttled)
 825			throttled = 1;
 826
 827		if (enqueue)
 828			sched_rt_rq_enqueue(rt_rq);
 829		raw_spin_unlock(&rq->lock);
 830	}
 831
 832	if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
 833		return 1;
 834
 835	return idle;
 836}
 837
 838static inline int rt_se_prio(struct sched_rt_entity *rt_se)
 839{
 840#ifdef CONFIG_RT_GROUP_SCHED
 841	struct rt_rq *rt_rq = group_rt_rq(rt_se);
 842
 843	if (rt_rq)
 844		return rt_rq->highest_prio.curr;
 845#endif
 846
 847	return rt_task_of(rt_se)->prio;
 848}
 849
 850static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 851{
 852	u64 runtime = sched_rt_runtime(rt_rq);
 853
 854	if (rt_rq->rt_throttled)
 855		return rt_rq_throttled(rt_rq);
 856
 857	if (runtime >= sched_rt_period(rt_rq))
 858		return 0;
 859
 860	balance_runtime(rt_rq);
 861	runtime = sched_rt_runtime(rt_rq);
 862	if (runtime == RUNTIME_INF)
 863		return 0;
 864
 865	if (rt_rq->rt_time > runtime) {
 866		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
 867
 868		/*
 869		 * Don't actually throttle groups that have no runtime assigned
 870		 * but accrue some time due to boosting.
 871		 */
 872		if (likely(rt_b->rt_runtime)) {
 873			static bool once = false;
 874
 875			rt_rq->rt_throttled = 1;
 876
 877			if (!once) {
 878				once = true;
 879				printk_sched("sched: RT throttling activated\n");
 880			}
 881		} else {
 882			/*
 883			 * In case we did anyway, make it go away,
 884			 * replenishment is a joke, since it will replenish us
 885			 * with exactly 0 ns.
 886			 */
 887			rt_rq->rt_time = 0;
 888		}
 889
 890		if (rt_rq_throttled(rt_rq)) {
 891			sched_rt_rq_dequeue(rt_rq);
 892			return 1;
 893		}
 894	}
 895
 896	return 0;
 897}
 898
 899/*
 900 * Update the current task's runtime statistics. Skip current tasks that
 901 * are not in our scheduling class.
 902 */
 903static void update_curr_rt(struct rq *rq)
 904{
 905	struct task_struct *curr = rq->curr;
 906	struct sched_rt_entity *rt_se = &curr->rt;
 907	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
 908	u64 delta_exec;
 909
 910	if (curr->sched_class != &rt_sched_class)
 911		return;
 912
 913	delta_exec = rq->clock_task - curr->se.exec_start;
 914	if (unlikely((s64)delta_exec < 0))
 915		delta_exec = 0;
 916
 917	schedstat_set(curr->se.statistics.exec_max,
 918		      max(curr->se.statistics.exec_max, delta_exec));
 919
 920	curr->se.sum_exec_runtime += delta_exec;
 921	account_group_exec_runtime(curr, delta_exec);
 922
 923	curr->se.exec_start = rq->clock_task;
 924	cpuacct_charge(curr, delta_exec);
 925
 926	sched_rt_avg_update(rq, delta_exec);
 927
 928	if (!rt_bandwidth_enabled())
 929		return;
 930
 931	for_each_sched_rt_entity(rt_se) {
 932		rt_rq = rt_rq_of_se(rt_se);
 
 933
 934		if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
 935			raw_spin_lock(&rt_rq->rt_runtime_lock);
 936			rt_rq->rt_time += delta_exec;
 937			if (sched_rt_runtime_exceeded(rt_rq))
 938				resched_task(curr);
 
 939			raw_spin_unlock(&rt_rq->rt_runtime_lock);
 
 
 940		}
 941	}
 942}
 943
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 944#if defined CONFIG_SMP
 945
 946static void
 947inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
 948{
 949	struct rq *rq = rq_of_rt_rq(rt_rq);
 950
 
 
 
 
 
 
 
 951	if (rq->online && prio < prev_prio)
 952		cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
 953}
 954
 955static void
 956dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
 957{
 958	struct rq *rq = rq_of_rt_rq(rt_rq);
 959
 
 
 
 
 
 
 
 960	if (rq->online && rt_rq->highest_prio.curr != prev_prio)
 961		cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
 962}
 963
 964#else /* CONFIG_SMP */
 965
 966static inline
 967void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
 968static inline
 969void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
 970
 971#endif /* CONFIG_SMP */
 972
 973#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
 974static void
 975inc_rt_prio(struct rt_rq *rt_rq, int prio)
 976{
 977	int prev_prio = rt_rq->highest_prio.curr;
 978
 979	if (prio < prev_prio)
 980		rt_rq->highest_prio.curr = prio;
 981
 982	inc_rt_prio_smp(rt_rq, prio, prev_prio);
 983}
 984
 985static void
 986dec_rt_prio(struct rt_rq *rt_rq, int prio)
 987{
 988	int prev_prio = rt_rq->highest_prio.curr;
 989
 990	if (rt_rq->rt_nr_running) {
 991
 992		WARN_ON(prio < prev_prio);
 993
 994		/*
 995		 * This may have been our highest task, and therefore
 996		 * we may have some recomputation to do
 997		 */
 998		if (prio == prev_prio) {
 999			struct rt_prio_array *array = &rt_rq->active;
1000
1001			rt_rq->highest_prio.curr =
1002				sched_find_first_bit(array->bitmap);
1003		}
1004
1005	} else
1006		rt_rq->highest_prio.curr = MAX_RT_PRIO;
 
1007
1008	dec_rt_prio_smp(rt_rq, prio, prev_prio);
1009}
1010
1011#else
1012
1013static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
1014static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
1015
1016#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
1017
1018#ifdef CONFIG_RT_GROUP_SCHED
1019
1020static void
1021inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1022{
1023	if (rt_se_boosted(rt_se))
1024		rt_rq->rt_nr_boosted++;
1025
1026	if (rt_rq->tg)
1027		start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
1028}
1029
1030static void
1031dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1032{
1033	if (rt_se_boosted(rt_se))
1034		rt_rq->rt_nr_boosted--;
1035
1036	WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1037}
1038
1039#else /* CONFIG_RT_GROUP_SCHED */
1040
1041static void
1042inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1043{
1044	start_rt_bandwidth(&def_rt_bandwidth);
1045}
1046
1047static inline
1048void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
1049
1050#endif /* CONFIG_RT_GROUP_SCHED */
1051
1052static inline
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1053void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1054{
1055	int prio = rt_se_prio(rt_se);
1056
1057	WARN_ON(!rt_prio(prio));
1058	rt_rq->rt_nr_running++;
 
1059
1060	inc_rt_prio(rt_rq, prio);
1061	inc_rt_migration(rt_se, rt_rq);
1062	inc_rt_group(rt_se, rt_rq);
1063}
1064
1065static inline
1066void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1067{
1068	WARN_ON(!rt_prio(rt_se_prio(rt_se)));
1069	WARN_ON(!rt_rq->rt_nr_running);
1070	rt_rq->rt_nr_running--;
 
1071
1072	dec_rt_prio(rt_rq, rt_se_prio(rt_se));
1073	dec_rt_migration(rt_se, rt_rq);
1074	dec_rt_group(rt_se, rt_rq);
1075}
1076
1077static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1078{
1079	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1080	struct rt_prio_array *array = &rt_rq->active;
1081	struct rt_rq *group_rq = group_rt_rq(rt_se);
1082	struct list_head *queue = array->queue + rt_se_prio(rt_se);
1083
1084	/*
1085	 * Don't enqueue the group if its throttled, or when empty.
1086	 * The latter is a consequence of the former when a child group
1087	 * get throttled and the current group doesn't have any other
1088	 * active members.
1089	 */
1090	if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
 
 
1091		return;
 
1092
1093	if (!rt_rq->rt_nr_running)
1094		list_add_leaf_rt_rq(rt_rq);
 
 
 
 
1095
1096	if (head)
1097		list_add(&rt_se->run_list, queue);
1098	else
1099		list_add_tail(&rt_se->run_list, queue);
1100	__set_bit(rt_se_prio(rt_se), array->bitmap);
1101
1102	inc_rt_tasks(rt_se, rt_rq);
1103}
1104
1105static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
1106{
1107	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1108	struct rt_prio_array *array = &rt_rq->active;
1109
1110	list_del_init(&rt_se->run_list);
1111	if (list_empty(array->queue + rt_se_prio(rt_se)))
1112		__clear_bit(rt_se_prio(rt_se), array->bitmap);
 
 
1113
1114	dec_rt_tasks(rt_se, rt_rq);
1115	if (!rt_rq->rt_nr_running)
1116		list_del_leaf_rt_rq(rt_rq);
1117}
1118
1119/*
1120 * Because the prio of an upper entry depends on the lower
1121 * entries, we must remove entries top - down.
1122 */
1123static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
1124{
1125	struct sched_rt_entity *back = NULL;
 
1126
1127	for_each_sched_rt_entity(rt_se) {
1128		rt_se->back = back;
1129		back = rt_se;
1130	}
1131
 
 
1132	for (rt_se = back; rt_se; rt_se = rt_se->back) {
1133		if (on_rt_rq(rt_se))
1134			__dequeue_rt_entity(rt_se);
1135	}
 
 
1136}
1137
1138static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1139{
1140	dequeue_rt_stack(rt_se);
 
 
 
 
1141	for_each_sched_rt_entity(rt_se)
1142		__enqueue_rt_entity(rt_se, head);
 
1143}
1144
1145static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
1146{
1147	dequeue_rt_stack(rt_se);
 
 
 
 
1148
1149	for_each_sched_rt_entity(rt_se) {
1150		struct rt_rq *rt_rq = group_rt_rq(rt_se);
1151
1152		if (rt_rq && rt_rq->rt_nr_running)
1153			__enqueue_rt_entity(rt_se, false);
1154	}
 
1155}
1156
1157/*
1158 * Adding/removing a task to/from a priority array:
1159 */
1160static void
1161enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1162{
1163	struct sched_rt_entity *rt_se = &p->rt;
1164
1165	if (flags & ENQUEUE_WAKEUP)
1166		rt_se->timeout = 0;
1167
1168	enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
 
 
 
1169
1170	if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
1171		enqueue_pushable_task(rq, p);
1172
1173	inc_nr_running(rq);
1174}
1175
1176static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1177{
1178	struct sched_rt_entity *rt_se = &p->rt;
1179
1180	update_curr_rt(rq);
1181	dequeue_rt_entity(rt_se);
1182
1183	dequeue_pushable_task(rq, p);
1184
1185	dec_nr_running(rq);
1186}
1187
1188/*
1189 * Put task to the head or the end of the run list without the overhead of
1190 * dequeue followed by enqueue.
1191 */
1192static void
1193requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
1194{
1195	if (on_rt_rq(rt_se)) {
1196		struct rt_prio_array *array = &rt_rq->active;
1197		struct list_head *queue = array->queue + rt_se_prio(rt_se);
1198
1199		if (head)
1200			list_move(&rt_se->run_list, queue);
1201		else
1202			list_move_tail(&rt_se->run_list, queue);
1203	}
1204}
1205
1206static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
1207{
1208	struct sched_rt_entity *rt_se = &p->rt;
1209	struct rt_rq *rt_rq;
1210
1211	for_each_sched_rt_entity(rt_se) {
1212		rt_rq = rt_rq_of_se(rt_se);
1213		requeue_rt_entity(rt_rq, rt_se, head);
1214	}
1215}
1216
1217static void yield_task_rt(struct rq *rq)
1218{
1219	requeue_task_rt(rq, rq->curr, 0);
1220}
1221
1222#ifdef CONFIG_SMP
1223static int find_lowest_rq(struct task_struct *task);
1224
1225static int
1226select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
1227{
1228	struct task_struct *curr;
1229	struct rq *rq;
1230	int cpu;
1231
1232	cpu = task_cpu(p);
1233
1234	if (p->nr_cpus_allowed == 1)
1235		goto out;
1236
1237	/* For anything but wake ups, just return the task_cpu */
1238	if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
1239		goto out;
1240
1241	rq = cpu_rq(cpu);
1242
1243	rcu_read_lock();
1244	curr = ACCESS_ONCE(rq->curr); /* unlocked access */
1245
1246	/*
1247	 * If the current task on @p's runqueue is an RT task, then
1248	 * try to see if we can wake this RT task up on another
1249	 * runqueue. Otherwise simply start this RT task
1250	 * on its current runqueue.
1251	 *
1252	 * We want to avoid overloading runqueues. If the woken
1253	 * task is a higher priority, then it will stay on this CPU
1254	 * and the lower prio task should be moved to another CPU.
1255	 * Even though this will probably make the lower prio task
1256	 * lose its cache, we do not want to bounce a higher task
1257	 * around just because it gave up its CPU, perhaps for a
1258	 * lock?
1259	 *
1260	 * For equal prio tasks, we just let the scheduler sort it out.
1261	 *
1262	 * Otherwise, just let it ride on the affined RQ and the
1263	 * post-schedule router will push the preempted task away
1264	 *
1265	 * This test is optimistic, if we get it wrong the load-balancer
1266	 * will have to sort it out.
 
 
 
 
1267	 */
1268	if (curr && unlikely(rt_task(curr)) &&
1269	    (curr->nr_cpus_allowed < 2 ||
1270	     curr->prio <= p->prio) &&
1271	    (p->nr_cpus_allowed > 1)) {
 
1272		int target = find_lowest_rq(p);
1273
1274		if (target != -1)
 
 
 
 
 
 
 
 
 
 
 
 
1275			cpu = target;
1276	}
 
 
1277	rcu_read_unlock();
1278
1279out:
1280	return cpu;
1281}
1282
1283static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
1284{
1285	if (rq->curr->nr_cpus_allowed == 1)
1286		return;
1287
1288	if (p->nr_cpus_allowed != 1
1289	    && cpupri_find(&rq->rd->cpupri, p, NULL))
 
1290		return;
1291
1292	if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
 
 
 
 
 
1293		return;
1294
1295	/*
1296	 * There appears to be other cpus that can accept
1297	 * current and none to run 'p', so lets reschedule
1298	 * to try and push current away:
1299	 */
1300	requeue_task_rt(rq, p, 1);
1301	resched_task(rq->curr);
1302}
1303
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1304#endif /* CONFIG_SMP */
1305
1306/*
1307 * Preempt the current task with a newly woken task if needed:
1308 */
1309static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
1310{
1311	if (p->prio < rq->curr->prio) {
1312		resched_task(rq->curr);
1313		return;
1314	}
1315
1316#ifdef CONFIG_SMP
1317	/*
1318	 * If:
1319	 *
1320	 * - the newly woken task is of equal priority to the current task
1321	 * - the newly woken task is non-migratable while current is migratable
1322	 * - current will be preempted on the next reschedule
1323	 *
1324	 * we should check to see if current can readily move to a different
1325	 * cpu.  If so, we will reschedule to allow the push logic to try
1326	 * to move current somewhere else, making room for our non-migratable
1327	 * task.
1328	 */
1329	if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1330		check_preempt_equal_prio(rq, p);
1331#endif
1332}
1333
1334static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
1335						   struct rt_rq *rt_rq)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1336{
1337	struct rt_prio_array *array = &rt_rq->active;
1338	struct sched_rt_entity *next = NULL;
1339	struct list_head *queue;
1340	int idx;
1341
1342	idx = sched_find_first_bit(array->bitmap);
1343	BUG_ON(idx >= MAX_RT_PRIO);
1344
1345	queue = array->queue + idx;
 
 
1346	next = list_entry(queue->next, struct sched_rt_entity, run_list);
1347
1348	return next;
1349}
1350
1351static struct task_struct *_pick_next_task_rt(struct rq *rq)
1352{
1353	struct sched_rt_entity *rt_se;
1354	struct task_struct *p;
1355	struct rt_rq *rt_rq;
1356
1357	rt_rq = &rq->rt;
1358
1359	if (!rt_rq->rt_nr_running)
1360		return NULL;
1361
1362	if (rt_rq_throttled(rt_rq))
1363		return NULL;
1364
1365	do {
1366		rt_se = pick_next_rt_entity(rq, rt_rq);
1367		BUG_ON(!rt_se);
 
1368		rt_rq = group_rt_rq(rt_se);
1369	} while (rt_rq);
1370
1371	p = rt_task_of(rt_se);
1372	p->se.exec_start = rq->clock_task;
 
 
 
 
 
 
 
 
 
1373
1374	return p;
1375}
1376
1377static struct task_struct *pick_next_task_rt(struct rq *rq)
1378{
1379	struct task_struct *p = _pick_next_task_rt(rq);
1380
1381	/* The running task is never eligible for pushing */
1382	if (p)
1383		dequeue_pushable_task(rq, p);
1384
1385#ifdef CONFIG_SMP
1386	/*
1387	 * We detect this state here so that we can avoid taking the RQ
1388	 * lock again later if there is no need to push
1389	 */
1390	rq->post_schedule = has_pushable_tasks(rq);
1391#endif
1392
1393	return p;
1394}
1395
1396static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
1397{
 
 
 
 
 
 
1398	update_curr_rt(rq);
1399
 
 
1400	/*
1401	 * The previous task needs to be made eligible for pushing
1402	 * if it is still active
1403	 */
1404	if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
1405		enqueue_pushable_task(rq, p);
1406}
1407
1408#ifdef CONFIG_SMP
1409
1410/* Only try algorithms three times */
1411#define RT_MAX_TRIES 3
1412
1413static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
1414{
1415	if (!task_running(rq, p) &&
1416	    (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
1417	    (p->nr_cpus_allowed > 1))
1418		return 1;
 
1419	return 0;
1420}
1421
1422/* Return the second highest RT task, NULL otherwise */
1423static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
 
 
 
1424{
1425	struct task_struct *next = NULL;
1426	struct sched_rt_entity *rt_se;
1427	struct rt_prio_array *array;
1428	struct rt_rq *rt_rq;
1429	int idx;
1430
1431	for_each_leaf_rt_rq(rt_rq, rq) {
1432		array = &rt_rq->active;
1433		idx = sched_find_first_bit(array->bitmap);
1434next_idx:
1435		if (idx >= MAX_RT_PRIO)
1436			continue;
1437		if (next && next->prio <= idx)
1438			continue;
1439		list_for_each_entry(rt_se, array->queue + idx, run_list) {
1440			struct task_struct *p;
1441
1442			if (!rt_entity_is_task(rt_se))
1443				continue;
1444
1445			p = rt_task_of(rt_se);
1446			if (pick_rt_task(rq, p, cpu)) {
1447				next = p;
1448				break;
1449			}
1450		}
1451		if (!next) {
1452			idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
1453			goto next_idx;
1454		}
1455	}
1456
1457	return next;
1458}
1459
1460static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
1461
1462static int find_lowest_rq(struct task_struct *task)
1463{
1464	struct sched_domain *sd;
1465	struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
1466	int this_cpu = smp_processor_id();
1467	int cpu      = task_cpu(task);
 
1468
1469	/* Make sure the mask is initialized first */
1470	if (unlikely(!lowest_mask))
1471		return -1;
1472
1473	if (task->nr_cpus_allowed == 1)
1474		return -1; /* No other targets possible */
1475
1476	if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1477		return -1; /* No targets found */
1478
1479	/*
1480	 * At this point we have built a mask of cpus representing the
1481	 * lowest priority tasks in the system.  Now we want to elect
1482	 * the best one based on our affinity and topology.
1483	 *
1484	 * We prioritize the last cpu that the task executed on since
1485	 * it is most likely cache-hot in that location.
1486	 */
1487	if (cpumask_test_cpu(cpu, lowest_mask))
1488		return cpu;
1489
1490	/*
1491	 * Otherwise, we consult the sched_domains span maps to figure
1492	 * out which cpu is logically closest to our hot cache data.
1493	 */
1494	if (!cpumask_test_cpu(this_cpu, lowest_mask))
1495		this_cpu = -1; /* Skip this_cpu opt if not among lowest */
1496
1497	rcu_read_lock();
1498	for_each_domain(cpu, sd) {
1499		if (sd->flags & SD_WAKE_AFFINE) {
1500			int best_cpu;
1501
1502			/*
1503			 * "this_cpu" is cheaper to preempt than a
1504			 * remote processor.
1505			 */
1506			if (this_cpu != -1 &&
1507			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1508				rcu_read_unlock();
1509				return this_cpu;
1510			}
1511
1512			best_cpu = cpumask_first_and(lowest_mask,
1513						     sched_domain_span(sd));
1514			if (best_cpu < nr_cpu_ids) {
1515				rcu_read_unlock();
1516				return best_cpu;
1517			}
1518		}
1519	}
1520	rcu_read_unlock();
1521
1522	/*
1523	 * And finally, if there were no matches within the domains
1524	 * just give the caller *something* to work with from the compatible
1525	 * locations.
1526	 */
1527	if (this_cpu != -1)
1528		return this_cpu;
1529
1530	cpu = cpumask_any(lowest_mask);
1531	if (cpu < nr_cpu_ids)
1532		return cpu;
 
1533	return -1;
1534}
1535
1536/* Will lock the rq it finds */
1537static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1538{
1539	struct rq *lowest_rq = NULL;
1540	int tries;
1541	int cpu;
1542
1543	for (tries = 0; tries < RT_MAX_TRIES; tries++) {
1544		cpu = find_lowest_rq(task);
1545
1546		if ((cpu == -1) || (cpu == rq->cpu))
1547			break;
1548
1549		lowest_rq = cpu_rq(cpu);
1550
 
 
 
 
 
 
 
 
 
 
1551		/* if the prio of this runqueue changed, try again */
1552		if (double_lock_balance(rq, lowest_rq)) {
1553			/*
1554			 * We had to unlock the run queue. In
1555			 * the mean time, task could have
1556			 * migrated already or had its affinity changed.
1557			 * Also make sure that it wasn't scheduled on its rq.
 
 
 
1558			 */
1559			if (unlikely(task_rq(task) != rq ||
1560				     !cpumask_test_cpu(lowest_rq->cpu,
1561						       tsk_cpus_allowed(task)) ||
1562				     task_running(rq, task) ||
1563				     !task->on_rq)) {
 
1564
1565				double_unlock_balance(rq, lowest_rq);
1566				lowest_rq = NULL;
1567				break;
1568			}
1569		}
1570
1571		/* If this rq is still suitable use it. */
1572		if (lowest_rq->rt.highest_prio.curr > task->prio)
1573			break;
1574
1575		/* try again */
1576		double_unlock_balance(rq, lowest_rq);
1577		lowest_rq = NULL;
1578	}
1579
1580	return lowest_rq;
1581}
1582
1583static struct task_struct *pick_next_pushable_task(struct rq *rq)
1584{
1585	struct task_struct *p;
1586
1587	if (!has_pushable_tasks(rq))
1588		return NULL;
1589
1590	p = plist_first_entry(&rq->rt.pushable_tasks,
1591			      struct task_struct, pushable_tasks);
1592
1593	BUG_ON(rq->cpu != task_cpu(p));
1594	BUG_ON(task_current(rq, p));
1595	BUG_ON(p->nr_cpus_allowed <= 1);
1596
1597	BUG_ON(!p->on_rq);
1598	BUG_ON(!rt_task(p));
1599
1600	return p;
1601}
1602
1603/*
1604 * If the current CPU has more than one RT task, see if the non
1605 * running task can migrate over to a CPU that is running a task
1606 * of lesser priority.
1607 */
1608static int push_rt_task(struct rq *rq)
1609{
1610	struct task_struct *next_task;
1611	struct rq *lowest_rq;
1612	int ret = 0;
1613
1614	if (!rq->rt.overloaded)
1615		return 0;
1616
1617	next_task = pick_next_pushable_task(rq);
1618	if (!next_task)
1619		return 0;
1620
1621#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1622       if (unlikely(task_running(rq, next_task)))
1623               return 0;
1624#endif
1625
1626retry:
1627	if (unlikely(next_task == rq->curr)) {
1628		WARN_ON(1);
1629		return 0;
1630	}
1631
1632	/*
1633	 * It's possible that the next_task slipped in of
1634	 * higher priority than current. If that's the case
1635	 * just reschedule current.
1636	 */
1637	if (unlikely(next_task->prio < rq->curr->prio)) {
1638		resched_task(rq->curr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1639		return 0;
1640	}
1641
 
 
 
1642	/* We might release rq lock */
1643	get_task_struct(next_task);
1644
1645	/* find_lock_lowest_rq locks the rq if found */
1646	lowest_rq = find_lock_lowest_rq(next_task, rq);
1647	if (!lowest_rq) {
1648		struct task_struct *task;
1649		/*
1650		 * find_lock_lowest_rq releases rq->lock
1651		 * so it is possible that next_task has migrated.
1652		 *
1653		 * We need to make sure that the task is still on the same
1654		 * run-queue and is also still the next task eligible for
1655		 * pushing.
1656		 */
1657		task = pick_next_pushable_task(rq);
1658		if (task_cpu(next_task) == rq->cpu && task == next_task) {
1659			/*
1660			 * The task hasn't migrated, and is still the next
1661			 * eligible task, but we failed to find a run-queue
1662			 * to push it to.  Do not retry in this case, since
1663			 * other cpus will pull from us when ready.
1664			 */
1665			goto out;
1666		}
1667
1668		if (!task)
1669			/* No more tasks, just exit */
1670			goto out;
1671
1672		/*
1673		 * Something has shifted, try again.
1674		 */
1675		put_task_struct(next_task);
1676		next_task = task;
1677		goto retry;
1678	}
1679
1680	deactivate_task(rq, next_task, 0);
1681	set_task_cpu(next_task, lowest_rq->cpu);
1682	activate_task(lowest_rq, next_task, 0);
 
1683	ret = 1;
1684
1685	resched_task(lowest_rq->curr);
1686
1687	double_unlock_balance(rq, lowest_rq);
1688
1689out:
1690	put_task_struct(next_task);
1691
1692	return ret;
1693}
1694
1695static void push_rt_tasks(struct rq *rq)
1696{
1697	/* push_rt_task will return true if it moved an RT */
1698	while (push_rt_task(rq))
1699		;
1700}
1701
1702static int pull_rt_task(struct rq *this_rq)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1703{
1704	int this_cpu = this_rq->cpu, ret = 0, cpu;
1705	struct task_struct *p;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1706	struct rq *src_rq;
 
1707
1708	if (likely(!rt_overloaded(this_rq)))
1709		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1710
1711	for_each_cpu(cpu, this_rq->rd->rto_mask) {
1712		if (this_cpu == cpu)
1713			continue;
1714
1715		src_rq = cpu_rq(cpu);
1716
1717		/*
1718		 * Don't bother taking the src_rq->lock if the next highest
1719		 * task is known to be lower-priority than our current task.
1720		 * This may look racy, but if this value is about to go
1721		 * logically higher, the src_rq will push this task away.
1722		 * And if its going logically lower, we do not care
1723		 */
1724		if (src_rq->rt.highest_prio.next >=
1725		    this_rq->rt.highest_prio.curr)
1726			continue;
1727
1728		/*
1729		 * We can potentially drop this_rq's lock in
1730		 * double_lock_balance, and another CPU could
1731		 * alter this_rq
1732		 */
 
1733		double_lock_balance(this_rq, src_rq);
1734
1735		/*
1736		 * Are there still pullable RT tasks?
 
1737		 */
1738		if (src_rq->rt.rt_nr_running <= 1)
1739			goto skip;
1740
1741		p = pick_next_highest_task_rt(src_rq, this_cpu);
1742
1743		/*
1744		 * Do we have an RT task that preempts
1745		 * the to-be-scheduled task?
1746		 */
1747		if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
1748			WARN_ON(p == src_rq->curr);
1749			WARN_ON(!p->on_rq);
1750
1751			/*
1752			 * There's a chance that p is higher in priority
1753			 * than what's currently running on its cpu.
1754			 * This is just that p is wakeing up and hasn't
1755			 * had a chance to schedule. We only pull
1756			 * p if it is lower in priority than the
1757			 * current task on the run queue
1758			 */
1759			if (p->prio < src_rq->curr->prio)
1760				goto skip;
1761
1762			ret = 1;
1763
1764			deactivate_task(src_rq, p, 0);
1765			set_task_cpu(p, this_cpu);
1766			activate_task(this_rq, p, 0);
 
 
 
1767			/*
1768			 * We continue with the search, just in
1769			 * case there's an even higher prio task
1770			 * in another runqueue. (low likelihood
1771			 * but possible)
1772			 */
1773		}
1774skip:
1775		double_unlock_balance(this_rq, src_rq);
1776	}
1777
1778	return ret;
1779}
1780
1781static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1782{
1783	/* Try to pull RT tasks here if we lower this rq's prio */
1784	if (rq->rt.highest_prio.curr > prev->prio)
1785		pull_rt_task(rq);
1786}
1787
1788static void post_schedule_rt(struct rq *rq)
1789{
1790	push_rt_tasks(rq);
1791}
1792
1793/*
1794 * If we are not running and we are not going to reschedule soon, we should
1795 * try to push tasks away now
1796 */
1797static void task_woken_rt(struct rq *rq, struct task_struct *p)
1798{
1799	if (!task_running(rq, p) &&
1800	    !test_tsk_need_resched(rq->curr) &&
1801	    has_pushable_tasks(rq) &&
1802	    p->nr_cpus_allowed > 1 &&
1803	    rt_task(rq->curr) &&
1804	    (rq->curr->nr_cpus_allowed < 2 ||
1805	     rq->curr->prio <= p->prio))
1806		push_rt_tasks(rq);
1807}
1808
1809static void set_cpus_allowed_rt(struct task_struct *p,
1810				const struct cpumask *new_mask)
1811{
1812	struct rq *rq;
1813	int weight;
1814
1815	BUG_ON(!rt_task(p));
1816
1817	if (!p->on_rq)
1818		return;
1819
1820	weight = cpumask_weight(new_mask);
1821
1822	/*
1823	 * Only update if the process changes its state from whether it
1824	 * can migrate or not.
1825	 */
1826	if ((p->nr_cpus_allowed > 1) == (weight > 1))
1827		return;
1828
1829	rq = task_rq(p);
1830
1831	/*
1832	 * The process used to be able to migrate OR it can now migrate
1833	 */
1834	if (weight <= 1) {
1835		if (!task_current(rq, p))
1836			dequeue_pushable_task(rq, p);
1837		BUG_ON(!rq->rt.rt_nr_migratory);
1838		rq->rt.rt_nr_migratory--;
1839	} else {
1840		if (!task_current(rq, p))
1841			enqueue_pushable_task(rq, p);
1842		rq->rt.rt_nr_migratory++;
1843	}
1844
1845	update_rt_migration(&rq->rt);
1846}
1847
1848/* Assumes rq->lock is held */
1849static void rq_online_rt(struct rq *rq)
1850{
1851	if (rq->rt.overloaded)
1852		rt_set_overload(rq);
1853
1854	__enable_runtime(rq);
1855
1856	cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
1857}
1858
1859/* Assumes rq->lock is held */
1860static void rq_offline_rt(struct rq *rq)
1861{
1862	if (rq->rt.overloaded)
1863		rt_clear_overload(rq);
1864
1865	__disable_runtime(rq);
1866
1867	cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1868}
1869
1870/*
1871 * When switch from the rt queue, we bring ourselves to a position
1872 * that we might want to pull RT tasks from other runqueues.
1873 */
1874static void switched_from_rt(struct rq *rq, struct task_struct *p)
1875{
1876	/*
1877	 * If there are other RT tasks then we will reschedule
1878	 * and the scheduling of the other RT tasks will handle
1879	 * the balancing. But if we are the last RT task
1880	 * we may need to handle the pulling of RT tasks
1881	 * now.
1882	 */
1883	if (p->on_rq && !rq->rt.rt_nr_running)
1884		pull_rt_task(rq);
 
 
1885}
1886
1887void init_sched_rt_class(void)
1888{
1889	unsigned int i;
1890
1891	for_each_possible_cpu(i) {
1892		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
1893					GFP_KERNEL, cpu_to_node(i));
1894	}
1895}
1896#endif /* CONFIG_SMP */
1897
1898/*
1899 * When switching a task to RT, we may overload the runqueue
1900 * with RT tasks. In this case we try to push them off to
1901 * other runqueues.
1902 */
1903static void switched_to_rt(struct rq *rq, struct task_struct *p)
1904{
1905	int check_resched = 1;
 
 
 
 
 
 
 
1906
1907	/*
1908	 * If we are already running, then there's nothing
1909	 * that needs to be done. But if we are not running
1910	 * we may need to preempt the current running task.
1911	 * If that current running task is also an RT task
1912	 * then see if we can move to another run queue.
1913	 */
1914	if (p->on_rq && rq->curr != p) {
1915#ifdef CONFIG_SMP
1916		if (rq->rt.overloaded && push_rt_task(rq) &&
1917		    /* Don't resched if we changed runqueues */
1918		    rq != task_rq(p))
1919			check_resched = 0;
1920#endif /* CONFIG_SMP */
1921		if (check_resched && p->prio < rq->curr->prio)
1922			resched_task(rq->curr);
1923	}
1924}
1925
1926/*
1927 * Priority of the task has changed. This may cause
1928 * us to initiate a push or pull.
1929 */
1930static void
1931prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
1932{
1933	if (!p->on_rq)
1934		return;
1935
1936	if (rq->curr == p) {
1937#ifdef CONFIG_SMP
1938		/*
1939		 * If our priority decreases while running, we
1940		 * may need to pull tasks to this runqueue.
1941		 */
1942		if (oldprio < p->prio)
1943			pull_rt_task(rq);
 
1944		/*
1945		 * If there's a higher priority task waiting to run
1946		 * then reschedule. Note, the above pull_rt_task
1947		 * can release the rq lock and p could migrate.
1948		 * Only reschedule if p is still on the same runqueue.
1949		 */
1950		if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
1951			resched_task(p);
1952#else
1953		/* For UP simply resched on drop of prio */
1954		if (oldprio < p->prio)
1955			resched_task(p);
1956#endif /* CONFIG_SMP */
1957	} else {
1958		/*
1959		 * This task is not running, but if it is
1960		 * greater than the current running task
1961		 * then reschedule.
1962		 */
1963		if (p->prio < rq->curr->prio)
1964			resched_task(rq->curr);
1965	}
1966}
1967
 
1968static void watchdog(struct rq *rq, struct task_struct *p)
1969{
1970	unsigned long soft, hard;
1971
1972	/* max may change after cur was read, this will be fixed next tick */
1973	soft = task_rlimit(p, RLIMIT_RTTIME);
1974	hard = task_rlimit_max(p, RLIMIT_RTTIME);
1975
1976	if (soft != RLIM_INFINITY) {
1977		unsigned long next;
1978
1979		p->rt.timeout++;
 
 
 
 
1980		next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1981		if (p->rt.timeout > next)
1982			p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
 
 
1983	}
1984}
 
 
 
1985
 
 
 
 
 
 
 
 
1986static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
1987{
1988	struct sched_rt_entity *rt_se = &p->rt;
1989
1990	update_curr_rt(rq);
 
1991
1992	watchdog(rq, p);
1993
1994	/*
1995	 * RR tasks need a special form of timeslice management.
1996	 * FIFO tasks have no timeslices.
1997	 */
1998	if (p->policy != SCHED_RR)
1999		return;
2000
2001	if (--p->rt.time_slice)
2002		return;
2003
2004	p->rt.time_slice = RR_TIMESLICE;
2005
2006	/*
2007	 * Requeue to the end of queue if we (and all of our ancestors) are the
2008	 * only element on the queue
2009	 */
2010	for_each_sched_rt_entity(rt_se) {
2011		if (rt_se->run_list.prev != rt_se->run_list.next) {
2012			requeue_task_rt(rq, p, 0);
2013			set_tsk_need_resched(p);
2014			return;
2015		}
2016	}
2017}
2018
2019static void set_curr_task_rt(struct rq *rq)
2020{
2021	struct task_struct *p = rq->curr;
2022
2023	p->se.exec_start = rq->clock_task;
2024
2025	/* The running task is never eligible for pushing */
2026	dequeue_pushable_task(rq, p);
2027}
2028
2029static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
2030{
2031	/*
2032	 * Time slice is 0 for SCHED_FIFO tasks
2033	 */
2034	if (task->policy == SCHED_RR)
2035		return RR_TIMESLICE;
2036	else
2037		return 0;
2038}
2039
2040const struct sched_class rt_sched_class = {
2041	.next			= &fair_sched_class,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2042	.enqueue_task		= enqueue_task_rt,
2043	.dequeue_task		= dequeue_task_rt,
2044	.yield_task		= yield_task_rt,
2045
2046	.check_preempt_curr	= check_preempt_curr_rt,
2047
2048	.pick_next_task		= pick_next_task_rt,
2049	.put_prev_task		= put_prev_task_rt,
 
2050
2051#ifdef CONFIG_SMP
 
 
2052	.select_task_rq		= select_task_rq_rt,
2053
2054	.set_cpus_allowed       = set_cpus_allowed_rt,
2055	.rq_online              = rq_online_rt,
2056	.rq_offline             = rq_offline_rt,
2057	.pre_schedule		= pre_schedule_rt,
2058	.post_schedule		= post_schedule_rt,
2059	.task_woken		= task_woken_rt,
2060	.switched_from		= switched_from_rt,
 
2061#endif
2062
2063	.set_curr_task          = set_curr_task_rt,
2064	.task_tick		= task_tick_rt,
2065
2066	.get_rr_interval	= get_rr_interval_rt,
2067
2068	.prio_changed		= prio_changed_rt,
2069	.switched_to		= switched_to_rt,
 
 
 
 
 
 
 
 
 
 
2070};
2071
2072#ifdef CONFIG_SCHED_DEBUG
2073extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2074
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2075void print_rt_stats(struct seq_file *m, int cpu)
2076{
2077	rt_rq_iter_t iter;
2078	struct rt_rq *rt_rq;
2079
2080	rcu_read_lock();
2081	for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2082		print_rt_rq(m, cpu, rt_rq);
2083	rcu_read_unlock();
2084}
2085#endif /* CONFIG_SCHED_DEBUG */