1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Scheduler topology setup/handling methods
4 */
5#include "sched.h"
6
7DEFINE_MUTEX(sched_domains_mutex);
8
9/* Protected by sched_domains_mutex: */
10static cpumask_var_t sched_domains_tmpmask;
11static cpumask_var_t sched_domains_tmpmask2;
12
13#ifdef CONFIG_SCHED_DEBUG
14
15static int __init sched_debug_setup(char *str)
16{
17 sched_debug_enabled = true;
18
19 return 0;
20}
21early_param("sched_debug", sched_debug_setup);
22
23static inline bool sched_debug(void)
24{
25 return sched_debug_enabled;
26}
27
28static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
29 struct cpumask *groupmask)
30{
31 struct sched_group *group = sd->groups;
32
33 cpumask_clear(groupmask);
34
35 printk(KERN_DEBUG "%*s domain-%d: ", level, "", level);
36
37 if (!(sd->flags & SD_LOAD_BALANCE)) {
38 printk("does not load-balance\n");
39 if (sd->parent)
40 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain has parent");
41 return -1;
42 }
43
44 printk(KERN_CONT "span=%*pbl level=%s\n",
45 cpumask_pr_args(sched_domain_span(sd)), sd->name);
46
47 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
48 printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu);
49 }
50 if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) {
51 printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
52 }
53
54 printk(KERN_DEBUG "%*s groups:", level + 1, "");
55 do {
56 if (!group) {
57 printk("\n");
58 printk(KERN_ERR "ERROR: group is NULL\n");
59 break;
60 }
61
62 if (!cpumask_weight(sched_group_span(group))) {
63 printk(KERN_CONT "\n");
64 printk(KERN_ERR "ERROR: empty group\n");
65 break;
66 }
67
68 if (!(sd->flags & SD_OVERLAP) &&
69 cpumask_intersects(groupmask, sched_group_span(group))) {
70 printk(KERN_CONT "\n");
71 printk(KERN_ERR "ERROR: repeated CPUs\n");
72 break;
73 }
74
75 cpumask_or(groupmask, groupmask, sched_group_span(group));
76
77 printk(KERN_CONT " %d:{ span=%*pbl",
78 group->sgc->id,
79 cpumask_pr_args(sched_group_span(group)));
80
81 if ((sd->flags & SD_OVERLAP) &&
82 !cpumask_equal(group_balance_mask(group), sched_group_span(group))) {
83 printk(KERN_CONT " mask=%*pbl",
84 cpumask_pr_args(group_balance_mask(group)));
85 }
86
87 if (group->sgc->capacity != SCHED_CAPACITY_SCALE)
88 printk(KERN_CONT " cap=%lu", group->sgc->capacity);
89
90 if (group == sd->groups && sd->child &&
91 !cpumask_equal(sched_domain_span(sd->child),
92 sched_group_span(group))) {
93 printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n");
94 }
95
96 printk(KERN_CONT " }");
97
98 group = group->next;
99
100 if (group != sd->groups)
101 printk(KERN_CONT ",");
102
103 } while (group != sd->groups);
104 printk(KERN_CONT "\n");
105
106 if (!cpumask_equal(sched_domain_span(sd), groupmask))
107 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
108
109 if (sd->parent &&
110 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
111 printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
112 return 0;
113}
114
115static void sched_domain_debug(struct sched_domain *sd, int cpu)
116{
117 int level = 0;
118
119 if (!sched_debug_enabled)
120 return;
121
122 if (!sd) {
123 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
124 return;
125 }
126
127 printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu);
128
129 for (;;) {
130 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
131 break;
132 level++;
133 sd = sd->parent;
134 if (!sd)
135 break;
136 }
137}
138#else /* !CONFIG_SCHED_DEBUG */
139
140# define sched_debug_enabled 0
141# define sched_domain_debug(sd, cpu) do { } while (0)
142static inline bool sched_debug(void)
143{
144 return false;
145}
146#endif /* CONFIG_SCHED_DEBUG */
147
148static int sd_degenerate(struct sched_domain *sd)
149{
150 if (cpumask_weight(sched_domain_span(sd)) == 1)
151 return 1;
152
153 /* Following flags need at least 2 groups */
154 if (sd->flags & (SD_LOAD_BALANCE |
155 SD_BALANCE_NEWIDLE |
156 SD_BALANCE_FORK |
157 SD_BALANCE_EXEC |
158 SD_SHARE_CPUCAPACITY |
159 SD_ASYM_CPUCAPACITY |
160 SD_SHARE_PKG_RESOURCES |
161 SD_SHARE_POWERDOMAIN)) {
162 if (sd->groups != sd->groups->next)
163 return 0;
164 }
165
166 /* Following flags don't use groups */
167 if (sd->flags & (SD_WAKE_AFFINE))
168 return 0;
169
170 return 1;
171}
172
173static int
174sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
175{
176 unsigned long cflags = sd->flags, pflags = parent->flags;
177
178 if (sd_degenerate(parent))
179 return 1;
180
181 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
182 return 0;
183
184 /* Flags needing groups don't count if only 1 group in parent */
185 if (parent->groups == parent->groups->next) {
186 pflags &= ~(SD_LOAD_BALANCE |
187 SD_BALANCE_NEWIDLE |
188 SD_BALANCE_FORK |
189 SD_BALANCE_EXEC |
190 SD_ASYM_CPUCAPACITY |
191 SD_SHARE_CPUCAPACITY |
192 SD_SHARE_PKG_RESOURCES |
193 SD_PREFER_SIBLING |
194 SD_SHARE_POWERDOMAIN);
195 if (nr_node_ids == 1)
196 pflags &= ~SD_SERIALIZE;
197 }
198 if (~cflags & pflags)
199 return 0;
200
201 return 1;
202}
203
204#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
205DEFINE_STATIC_KEY_FALSE(sched_energy_present);
206unsigned int sysctl_sched_energy_aware = 1;
207DEFINE_MUTEX(sched_energy_mutex);
208bool sched_energy_update;
209
210#ifdef CONFIG_PROC_SYSCTL
211int sched_energy_aware_handler(struct ctl_table *table, int write,
212 void __user *buffer, size_t *lenp, loff_t *ppos)
213{
214 int ret, state;
215
216 if (write && !capable(CAP_SYS_ADMIN))
217 return -EPERM;
218
219 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
220 if (!ret && write) {
221 state = static_branch_unlikely(&sched_energy_present);
222 if (state != sysctl_sched_energy_aware) {
223 mutex_lock(&sched_energy_mutex);
224 sched_energy_update = 1;
225 rebuild_sched_domains();
226 sched_energy_update = 0;
227 mutex_unlock(&sched_energy_mutex);
228 }
229 }
230
231 return ret;
232}
233#endif
234
235static void free_pd(struct perf_domain *pd)
236{
237 struct perf_domain *tmp;
238
239 while (pd) {
240 tmp = pd->next;
241 kfree(pd);
242 pd = tmp;
243 }
244}
245
246static struct perf_domain *find_pd(struct perf_domain *pd, int cpu)
247{
248 while (pd) {
249 if (cpumask_test_cpu(cpu, perf_domain_span(pd)))
250 return pd;
251 pd = pd->next;
252 }
253
254 return NULL;
255}
256
257static struct perf_domain *pd_init(int cpu)
258{
259 struct em_perf_domain *obj = em_cpu_get(cpu);
260 struct perf_domain *pd;
261
262 if (!obj) {
263 if (sched_debug())
264 pr_info("%s: no EM found for CPU%d\n", __func__, cpu);
265 return NULL;
266 }
267
268 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
269 if (!pd)
270 return NULL;
271 pd->em_pd = obj;
272
273 return pd;
274}
275
276static void perf_domain_debug(const struct cpumask *cpu_map,
277 struct perf_domain *pd)
278{
279 if (!sched_debug() || !pd)
280 return;
281
282 printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map));
283
284 while (pd) {
285 printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_cstate=%d }",
286 cpumask_first(perf_domain_span(pd)),
287 cpumask_pr_args(perf_domain_span(pd)),
288 em_pd_nr_cap_states(pd->em_pd));
289 pd = pd->next;
290 }
291
292 printk(KERN_CONT "\n");
293}
294
295static void destroy_perf_domain_rcu(struct rcu_head *rp)
296{
297 struct perf_domain *pd;
298
299 pd = container_of(rp, struct perf_domain, rcu);
300 free_pd(pd);
301}
302
303static void sched_energy_set(bool has_eas)
304{
305 if (!has_eas && static_branch_unlikely(&sched_energy_present)) {
306 if (sched_debug())
307 pr_info("%s: stopping EAS\n", __func__);
308 static_branch_disable_cpuslocked(&sched_energy_present);
309 } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) {
310 if (sched_debug())
311 pr_info("%s: starting EAS\n", __func__);
312 static_branch_enable_cpuslocked(&sched_energy_present);
313 }
314}
315
316/*
317 * EAS can be used on a root domain if it meets all the following conditions:
318 * 1. an Energy Model (EM) is available;
319 * 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
320 * 3. the EM complexity is low enough to keep scheduling overheads low;
321 * 4. schedutil is driving the frequency of all CPUs of the rd;
322 *
323 * The complexity of the Energy Model is defined as:
324 *
325 * C = nr_pd * (nr_cpus + nr_cs)
326 *
327 * with parameters defined as:
328 * - nr_pd: the number of performance domains
329 * - nr_cpus: the number of CPUs
330 * - nr_cs: the sum of the number of capacity states of all performance
331 * domains (for example, on a system with 2 performance domains,
332 * with 10 capacity states each, nr_cs = 2 * 10 = 20).
333 *
334 * It is generally not a good idea to use such a model in the wake-up path on
335 * very complex platforms because of the associated scheduling overheads. The
336 * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs
337 * with per-CPU DVFS and less than 8 capacity states each, for example.
338 */
339#define EM_MAX_COMPLEXITY 2048
340
341extern struct cpufreq_governor schedutil_gov;
342static bool build_perf_domains(const struct cpumask *cpu_map)
343{
344 int i, nr_pd = 0, nr_cs = 0, nr_cpus = cpumask_weight(cpu_map);
345 struct perf_domain *pd = NULL, *tmp;
346 int cpu = cpumask_first(cpu_map);
347 struct root_domain *rd = cpu_rq(cpu)->rd;
348 struct cpufreq_policy *policy;
349 struct cpufreq_governor *gov;
350
351 if (!sysctl_sched_energy_aware)
352 goto free;
353
354 /* EAS is enabled for asymmetric CPU capacity topologies. */
355 if (!per_cpu(sd_asym_cpucapacity, cpu)) {
356 if (sched_debug()) {
357 pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n",
358 cpumask_pr_args(cpu_map));
359 }
360 goto free;
361 }
362
363 for_each_cpu(i, cpu_map) {
364 /* Skip already covered CPUs. */
365 if (find_pd(pd, i))
366 continue;
367
368 /* Do not attempt EAS if schedutil is not being used. */
369 policy = cpufreq_cpu_get(i);
370 if (!policy)
371 goto free;
372 gov = policy->governor;
373 cpufreq_cpu_put(policy);
374 if (gov != &schedutil_gov) {
375 if (rd->pd)
376 pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n",
377 cpumask_pr_args(cpu_map));
378 goto free;
379 }
380
381 /* Create the new pd and add it to the local list. */
382 tmp = pd_init(i);
383 if (!tmp)
384 goto free;
385 tmp->next = pd;
386 pd = tmp;
387
388 /*
389 * Count performance domains and capacity states for the
390 * complexity check.
391 */
392 nr_pd++;
393 nr_cs += em_pd_nr_cap_states(pd->em_pd);
394 }
395
396 /* Bail out if the Energy Model complexity is too high. */
397 if (nr_pd * (nr_cs + nr_cpus) > EM_MAX_COMPLEXITY) {
398 WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n",
399 cpumask_pr_args(cpu_map));
400 goto free;
401 }
402
403 perf_domain_debug(cpu_map, pd);
404
405 /* Attach the new list of performance domains to the root domain. */
406 tmp = rd->pd;
407 rcu_assign_pointer(rd->pd, pd);
408 if (tmp)
409 call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
410
411 return !!pd;
412
413free:
414 free_pd(pd);
415 tmp = rd->pd;
416 rcu_assign_pointer(rd->pd, NULL);
417 if (tmp)
418 call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
419
420 return false;
421}
422#else
423static void free_pd(struct perf_domain *pd) { }
424#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/
425
426static void free_rootdomain(struct rcu_head *rcu)
427{
428 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
429
430 cpupri_cleanup(&rd->cpupri);
431 cpudl_cleanup(&rd->cpudl);
432 free_cpumask_var(rd->dlo_mask);
433 free_cpumask_var(rd->rto_mask);
434 free_cpumask_var(rd->online);
435 free_cpumask_var(rd->span);
436 free_pd(rd->pd);
437 kfree(rd);
438}
439
440void rq_attach_root(struct rq *rq, struct root_domain *rd)
441{
442 struct root_domain *old_rd = NULL;
443 unsigned long flags;
444
445 raw_spin_lock_irqsave(&rq->lock, flags);
446
447 if (rq->rd) {
448 old_rd = rq->rd;
449
450 if (cpumask_test_cpu(rq->cpu, old_rd->online))
451 set_rq_offline(rq);
452
453 cpumask_clear_cpu(rq->cpu, old_rd->span);
454
455 /*
456 * If we dont want to free the old_rd yet then
457 * set old_rd to NULL to skip the freeing later
458 * in this function:
459 */
460 if (!atomic_dec_and_test(&old_rd->refcount))
461 old_rd = NULL;
462 }
463
464 atomic_inc(&rd->refcount);
465 rq->rd = rd;
466
467 cpumask_set_cpu(rq->cpu, rd->span);
468 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
469 set_rq_online(rq);
470
471 raw_spin_unlock_irqrestore(&rq->lock, flags);
472
473 if (old_rd)
474 call_rcu(&old_rd->rcu, free_rootdomain);
475}
476
477void sched_get_rd(struct root_domain *rd)
478{
479 atomic_inc(&rd->refcount);
480}
481
482void sched_put_rd(struct root_domain *rd)
483{
484 if (!atomic_dec_and_test(&rd->refcount))
485 return;
486
487 call_rcu(&rd->rcu, free_rootdomain);
488}
489
490static int init_rootdomain(struct root_domain *rd)
491{
492 if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
493 goto out;
494 if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
495 goto free_span;
496 if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
497 goto free_online;
498 if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
499 goto free_dlo_mask;
500
501#ifdef HAVE_RT_PUSH_IPI
502 rd->rto_cpu = -1;
503 raw_spin_lock_init(&rd->rto_lock);
504 init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
505#endif
506
507 init_dl_bw(&rd->dl_bw);
508 if (cpudl_init(&rd->cpudl) != 0)
509 goto free_rto_mask;
510
511 if (cpupri_init(&rd->cpupri) != 0)
512 goto free_cpudl;
513 return 0;
514
515free_cpudl:
516 cpudl_cleanup(&rd->cpudl);
517free_rto_mask:
518 free_cpumask_var(rd->rto_mask);
519free_dlo_mask:
520 free_cpumask_var(rd->dlo_mask);
521free_online:
522 free_cpumask_var(rd->online);
523free_span:
524 free_cpumask_var(rd->span);
525out:
526 return -ENOMEM;
527}
528
529/*
530 * By default the system creates a single root-domain with all CPUs as
531 * members (mimicking the global state we have today).
532 */
533struct root_domain def_root_domain;
534
535void init_defrootdomain(void)
536{
537 init_rootdomain(&def_root_domain);
538
539 atomic_set(&def_root_domain.refcount, 1);
540}
541
542static struct root_domain *alloc_rootdomain(void)
543{
544 struct root_domain *rd;
545
546 rd = kzalloc(sizeof(*rd), GFP_KERNEL);
547 if (!rd)
548 return NULL;
549
550 if (init_rootdomain(rd) != 0) {
551 kfree(rd);
552 return NULL;
553 }
554
555 return rd;
556}
557
558static void free_sched_groups(struct sched_group *sg, int free_sgc)
559{
560 struct sched_group *tmp, *first;
561
562 if (!sg)
563 return;
564
565 first = sg;
566 do {
567 tmp = sg->next;
568
569 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
570 kfree(sg->sgc);
571
572 if (atomic_dec_and_test(&sg->ref))
573 kfree(sg);
574 sg = tmp;
575 } while (sg != first);
576}
577
578static void destroy_sched_domain(struct sched_domain *sd)
579{
580 /*
581 * A normal sched domain may have multiple group references, an
582 * overlapping domain, having private groups, only one. Iterate,
583 * dropping group/capacity references, freeing where none remain.
584 */
585 free_sched_groups(sd->groups, 1);
586
587 if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
588 kfree(sd->shared);
589 kfree(sd);
590}
591
592static void destroy_sched_domains_rcu(struct rcu_head *rcu)
593{
594 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
595
596 while (sd) {
597 struct sched_domain *parent = sd->parent;
598 destroy_sched_domain(sd);
599 sd = parent;
600 }
601}
602
603static void destroy_sched_domains(struct sched_domain *sd)
604{
605 if (sd)
606 call_rcu(&sd->rcu, destroy_sched_domains_rcu);
607}
608
609/*
610 * Keep a special pointer to the highest sched_domain that has
611 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
612 * allows us to avoid some pointer chasing select_idle_sibling().
613 *
614 * Also keep a unique ID per domain (we use the first CPU number in
615 * the cpumask of the domain), this allows us to quickly tell if
616 * two CPUs are in the same cache domain, see cpus_share_cache().
617 */
618DEFINE_PER_CPU(struct sched_domain *, sd_llc);
619DEFINE_PER_CPU(int, sd_llc_size);
620DEFINE_PER_CPU(int, sd_llc_id);
621DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
622DEFINE_PER_CPU(struct sched_domain *, sd_numa);
623DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing);
624DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
625DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
626
627static void update_top_cache_domain(int cpu)
628{
629 struct sched_domain_shared *sds = NULL;
630 struct sched_domain *sd;
631 int id = cpu;
632 int size = 1;
633
634 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
635 if (sd) {
636 id = cpumask_first(sched_domain_span(sd));
637 size = cpumask_weight(sched_domain_span(sd));
638 sds = sd->shared;
639 }
640
641 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
642 per_cpu(sd_llc_size, cpu) = size;
643 per_cpu(sd_llc_id, cpu) = id;
644 rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
645
646 sd = lowest_flag_domain(cpu, SD_NUMA);
647 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
648
649 sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
650 rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd);
651
652 sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY);
653 rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd);
654}
655
656/*
657 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
658 * hold the hotplug lock.
659 */
660static void
661cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
662{
663 struct rq *rq = cpu_rq(cpu);
664 struct sched_domain *tmp;
665
666 /* Remove the sched domains which do not contribute to scheduling. */
667 for (tmp = sd; tmp; ) {
668 struct sched_domain *parent = tmp->parent;
669 if (!parent)
670 break;
671
672 if (sd_parent_degenerate(tmp, parent)) {
673 tmp->parent = parent->parent;
674 if (parent->parent)
675 parent->parent->child = tmp;
676 /*
677 * Transfer SD_PREFER_SIBLING down in case of a
678 * degenerate parent; the spans match for this
679 * so the property transfers.
680 */
681 if (parent->flags & SD_PREFER_SIBLING)
682 tmp->flags |= SD_PREFER_SIBLING;
683 destroy_sched_domain(parent);
684 } else
685 tmp = tmp->parent;
686 }
687
688 if (sd && sd_degenerate(sd)) {
689 tmp = sd;
690 sd = sd->parent;
691 destroy_sched_domain(tmp);
692 if (sd)
693 sd->child = NULL;
694 }
695
696 sched_domain_debug(sd, cpu);
697
698 rq_attach_root(rq, rd);
699 tmp = rq->sd;
700 rcu_assign_pointer(rq->sd, sd);
701 dirty_sched_domain_sysctl(cpu);
702 destroy_sched_domains(tmp);
703
704 update_top_cache_domain(cpu);
705}
706
707struct s_data {
708 struct sched_domain * __percpu *sd;
709 struct root_domain *rd;
710};
711
712enum s_alloc {
713 sa_rootdomain,
714 sa_sd,
715 sa_sd_storage,
716 sa_none,
717};
718
719/*
720 * Return the canonical balance CPU for this group, this is the first CPU
721 * of this group that's also in the balance mask.
722 *
723 * The balance mask are all those CPUs that could actually end up at this
724 * group. See build_balance_mask().
725 *
726 * Also see should_we_balance().
727 */
728int group_balance_cpu(struct sched_group *sg)
729{
730 return cpumask_first(group_balance_mask(sg));
731}
732
733
734/*
735 * NUMA topology (first read the regular topology blurb below)
736 *
737 * Given a node-distance table, for example:
738 *
739 * node 0 1 2 3
740 * 0: 10 20 30 20
741 * 1: 20 10 20 30
742 * 2: 30 20 10 20
743 * 3: 20 30 20 10
744 *
745 * which represents a 4 node ring topology like:
746 *
747 * 0 ----- 1
748 * | |
749 * | |
750 * | |
751 * 3 ----- 2
752 *
753 * We want to construct domains and groups to represent this. The way we go
754 * about doing this is to build the domains on 'hops'. For each NUMA level we
755 * construct the mask of all nodes reachable in @level hops.
756 *
757 * For the above NUMA topology that gives 3 levels:
758 *
759 * NUMA-2 0-3 0-3 0-3 0-3
760 * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2}
761 *
762 * NUMA-1 0-1,3 0-2 1-3 0,2-3
763 * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3}
764 *
765 * NUMA-0 0 1 2 3
766 *
767 *
768 * As can be seen; things don't nicely line up as with the regular topology.
769 * When we iterate a domain in child domain chunks some nodes can be
770 * represented multiple times -- hence the "overlap" naming for this part of
771 * the topology.
772 *
773 * In order to minimize this overlap, we only build enough groups to cover the
774 * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3.
775 *
776 * Because:
777 *
778 * - the first group of each domain is its child domain; this
779 * gets us the first 0-1,3
780 * - the only uncovered node is 2, who's child domain is 1-3.
781 *
782 * However, because of the overlap, computing a unique CPU for each group is
783 * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both
784 * groups include the CPUs of Node-0, while those CPUs would not in fact ever
785 * end up at those groups (they would end up in group: 0-1,3).
786 *
787 * To correct this we have to introduce the group balance mask. This mask
788 * will contain those CPUs in the group that can reach this group given the
789 * (child) domain tree.
790 *
791 * With this we can once again compute balance_cpu and sched_group_capacity
792 * relations.
793 *
794 * XXX include words on how balance_cpu is unique and therefore can be
795 * used for sched_group_capacity links.
796 *
797 *
798 * Another 'interesting' topology is:
799 *
800 * node 0 1 2 3
801 * 0: 10 20 20 30
802 * 1: 20 10 20 20
803 * 2: 20 20 10 20
804 * 3: 30 20 20 10
805 *
806 * Which looks a little like:
807 *
808 * 0 ----- 1
809 * | / |
810 * | / |
811 * | / |
812 * 2 ----- 3
813 *
814 * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3
815 * are not.
816 *
817 * This leads to a few particularly weird cases where the sched_domain's are
818 * not of the same number for each CPU. Consider:
819 *
820 * NUMA-2 0-3 0-3
821 * groups: {0-2},{1-3} {1-3},{0-2}
822 *
823 * NUMA-1 0-2 0-3 0-3 1-3
824 *
825 * NUMA-0 0 1 2 3
826 *
827 */
828
829
830/*
831 * Build the balance mask; it contains only those CPUs that can arrive at this
832 * group and should be considered to continue balancing.
833 *
834 * We do this during the group creation pass, therefore the group information
835 * isn't complete yet, however since each group represents a (child) domain we
836 * can fully construct this using the sched_domain bits (which are already
837 * complete).
838 */
839static void
840build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask)
841{
842 const struct cpumask *sg_span = sched_group_span(sg);
843 struct sd_data *sdd = sd->private;
844 struct sched_domain *sibling;
845 int i;
846
847 cpumask_clear(mask);
848
849 for_each_cpu(i, sg_span) {
850 sibling = *per_cpu_ptr(sdd->sd, i);
851
852 /*
853 * Can happen in the asymmetric case, where these siblings are
854 * unused. The mask will not be empty because those CPUs that
855 * do have the top domain _should_ span the domain.
856 */
857 if (!sibling->child)
858 continue;
859
860 /* If we would not end up here, we can't continue from here */
861 if (!cpumask_equal(sg_span, sched_domain_span(sibling->child)))
862 continue;
863
864 cpumask_set_cpu(i, mask);
865 }
866
867 /* We must not have empty masks here */
868 WARN_ON_ONCE(cpumask_empty(mask));
869}
870
871/*
872 * XXX: This creates per-node group entries; since the load-balancer will
873 * immediately access remote memory to construct this group's load-balance
874 * statistics having the groups node local is of dubious benefit.
875 */
876static struct sched_group *
877build_group_from_child_sched_domain(struct sched_domain *sd, int cpu)
878{
879 struct sched_group *sg;
880 struct cpumask *sg_span;
881
882 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
883 GFP_KERNEL, cpu_to_node(cpu));
884
885 if (!sg)
886 return NULL;
887
888 sg_span = sched_group_span(sg);
889 if (sd->child)
890 cpumask_copy(sg_span, sched_domain_span(sd->child));
891 else
892 cpumask_copy(sg_span, sched_domain_span(sd));
893
894 atomic_inc(&sg->ref);
895 return sg;
896}
897
898static void init_overlap_sched_group(struct sched_domain *sd,
899 struct sched_group *sg)
900{
901 struct cpumask *mask = sched_domains_tmpmask2;
902 struct sd_data *sdd = sd->private;
903 struct cpumask *sg_span;
904 int cpu;
905
906 build_balance_mask(sd, sg, mask);
907 cpu = cpumask_first_and(sched_group_span(sg), mask);
908
909 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
910 if (atomic_inc_return(&sg->sgc->ref) == 1)
911 cpumask_copy(group_balance_mask(sg), mask);
912 else
913 WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask));
914
915 /*
916 * Initialize sgc->capacity such that even if we mess up the
917 * domains and no possible iteration will get us here, we won't
918 * die on a /0 trap.
919 */
920 sg_span = sched_group_span(sg);
921 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
922 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
923 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
924}
925
926static int
927build_overlap_sched_groups(struct sched_domain *sd, int cpu)
928{
929 struct sched_group *first = NULL, *last = NULL, *sg;
930 const struct cpumask *span = sched_domain_span(sd);
931 struct cpumask *covered = sched_domains_tmpmask;
932 struct sd_data *sdd = sd->private;
933 struct sched_domain *sibling;
934 int i;
935
936 cpumask_clear(covered);
937
938 for_each_cpu_wrap(i, span, cpu) {
939 struct cpumask *sg_span;
940
941 if (cpumask_test_cpu(i, covered))
942 continue;
943
944 sibling = *per_cpu_ptr(sdd->sd, i);
945
946 /*
947 * Asymmetric node setups can result in situations where the
948 * domain tree is of unequal depth, make sure to skip domains
949 * that already cover the entire range.
950 *
951 * In that case build_sched_domains() will have terminated the
952 * iteration early and our sibling sd spans will be empty.
953 * Domains should always include the CPU they're built on, so
954 * check that.
955 */
956 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
957 continue;
958
959 sg = build_group_from_child_sched_domain(sibling, cpu);
960 if (!sg)
961 goto fail;
962
963 sg_span = sched_group_span(sg);
964 cpumask_or(covered, covered, sg_span);
965
966 init_overlap_sched_group(sd, sg);
967
968 if (!first)
969 first = sg;
970 if (last)
971 last->next = sg;
972 last = sg;
973 last->next = first;
974 }
975 sd->groups = first;
976
977 return 0;
978
979fail:
980 free_sched_groups(first, 0);
981
982 return -ENOMEM;
983}
984
985
986/*
987 * Package topology (also see the load-balance blurb in fair.c)
988 *
989 * The scheduler builds a tree structure to represent a number of important
990 * topology features. By default (default_topology[]) these include:
991 *
992 * - Simultaneous multithreading (SMT)
993 * - Multi-Core Cache (MC)
994 * - Package (DIE)
995 *
996 * Where the last one more or less denotes everything up to a NUMA node.
997 *
998 * The tree consists of 3 primary data structures:
999 *
1000 * sched_domain -> sched_group -> sched_group_capacity
1001 * ^ ^ ^ ^
1002 * `-' `-'
1003 *
1004 * The sched_domains are per-CPU and have a two way link (parent & child) and
1005 * denote the ever growing mask of CPUs belonging to that level of topology.
1006 *
1007 * Each sched_domain has a circular (double) linked list of sched_group's, each
1008 * denoting the domains of the level below (or individual CPUs in case of the
1009 * first domain level). The sched_group linked by a sched_domain includes the
1010 * CPU of that sched_domain [*].
1011 *
1012 * Take for instance a 2 threaded, 2 core, 2 cache cluster part:
1013 *
1014 * CPU 0 1 2 3 4 5 6 7
1015 *
1016 * DIE [ ]
1017 * MC [ ] [ ]
1018 * SMT [ ] [ ] [ ] [ ]
1019 *
1020 * - or -
1021 *
1022 * DIE 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7
1023 * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7
1024 * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7
1025 *
1026 * CPU 0 1 2 3 4 5 6 7
1027 *
1028 * One way to think about it is: sched_domain moves you up and down among these
1029 * topology levels, while sched_group moves you sideways through it, at child
1030 * domain granularity.
1031 *
1032 * sched_group_capacity ensures each unique sched_group has shared storage.
1033 *
1034 * There are two related construction problems, both require a CPU that
1035 * uniquely identify each group (for a given domain):
1036 *
1037 * - The first is the balance_cpu (see should_we_balance() and the
1038 * load-balance blub in fair.c); for each group we only want 1 CPU to
1039 * continue balancing at a higher domain.
1040 *
1041 * - The second is the sched_group_capacity; we want all identical groups
1042 * to share a single sched_group_capacity.
1043 *
1044 * Since these topologies are exclusive by construction. That is, its
1045 * impossible for an SMT thread to belong to multiple cores, and cores to
1046 * be part of multiple caches. There is a very clear and unique location
1047 * for each CPU in the hierarchy.
1048 *
1049 * Therefore computing a unique CPU for each group is trivial (the iteration
1050 * mask is redundant and set all 1s; all CPUs in a group will end up at _that_
1051 * group), we can simply pick the first CPU in each group.
1052 *
1053 *
1054 * [*] in other words, the first group of each domain is its child domain.
1055 */
1056
1057static struct sched_group *get_group(int cpu, struct sd_data *sdd)
1058{
1059 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
1060 struct sched_domain *child = sd->child;
1061 struct sched_group *sg;
1062
1063 if (child)
1064 cpu = cpumask_first(sched_domain_span(child));
1065
1066 sg = *per_cpu_ptr(sdd->sg, cpu);
1067 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
1068
1069 /* For claim_allocations: */
1070 atomic_inc(&sg->ref);
1071 atomic_inc(&sg->sgc->ref);
1072
1073 if (child) {
1074 cpumask_copy(sched_group_span(sg), sched_domain_span(child));
1075 cpumask_copy(group_balance_mask(sg), sched_group_span(sg));
1076 } else {
1077 cpumask_set_cpu(cpu, sched_group_span(sg));
1078 cpumask_set_cpu(cpu, group_balance_mask(sg));
1079 }
1080
1081 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
1082 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
1083 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
1084
1085 return sg;
1086}
1087
1088/*
1089 * build_sched_groups will build a circular linked list of the groups
1090 * covered by the given span, and will set each group's ->cpumask correctly,
1091 * and ->cpu_capacity to 0.
1092 *
1093 * Assumes the sched_domain tree is fully constructed
1094 */
1095static int
1096build_sched_groups(struct sched_domain *sd, int cpu)
1097{
1098 struct sched_group *first = NULL, *last = NULL;
1099 struct sd_data *sdd = sd->private;
1100 const struct cpumask *span = sched_domain_span(sd);
1101 struct cpumask *covered;
1102 int i;
1103
1104 lockdep_assert_held(&sched_domains_mutex);
1105 covered = sched_domains_tmpmask;
1106
1107 cpumask_clear(covered);
1108
1109 for_each_cpu_wrap(i, span, cpu) {
1110 struct sched_group *sg;
1111
1112 if (cpumask_test_cpu(i, covered))
1113 continue;
1114
1115 sg = get_group(i, sdd);
1116
1117 cpumask_or(covered, covered, sched_group_span(sg));
1118
1119 if (!first)
1120 first = sg;
1121 if (last)
1122 last->next = sg;
1123 last = sg;
1124 }
1125 last->next = first;
1126 sd->groups = first;
1127
1128 return 0;
1129}
1130
1131/*
1132 * Initialize sched groups cpu_capacity.
1133 *
1134 * cpu_capacity indicates the capacity of sched group, which is used while
1135 * distributing the load between different sched groups in a sched domain.
1136 * Typically cpu_capacity for all the groups in a sched domain will be same
1137 * unless there are asymmetries in the topology. If there are asymmetries,
1138 * group having more cpu_capacity will pickup more load compared to the
1139 * group having less cpu_capacity.
1140 */
1141static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
1142{
1143 struct sched_group *sg = sd->groups;
1144
1145 WARN_ON(!sg);
1146
1147 do {
1148 int cpu, max_cpu = -1;
1149
1150 sg->group_weight = cpumask_weight(sched_group_span(sg));
1151
1152 if (!(sd->flags & SD_ASYM_PACKING))
1153 goto next;
1154
1155 for_each_cpu(cpu, sched_group_span(sg)) {
1156 if (max_cpu < 0)
1157 max_cpu = cpu;
1158 else if (sched_asym_prefer(cpu, max_cpu))
1159 max_cpu = cpu;
1160 }
1161 sg->asym_prefer_cpu = max_cpu;
1162
1163next:
1164 sg = sg->next;
1165 } while (sg != sd->groups);
1166
1167 if (cpu != group_balance_cpu(sg))
1168 return;
1169
1170 update_group_capacity(sd, cpu);
1171}
1172
1173/*
1174 * Initializers for schedule domains
1175 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
1176 */
1177
1178static int default_relax_domain_level = -1;
1179int sched_domain_level_max;
1180
1181static int __init setup_relax_domain_level(char *str)
1182{
1183 if (kstrtoint(str, 0, &default_relax_domain_level))
1184 pr_warn("Unable to set relax_domain_level\n");
1185
1186 return 1;
1187}
1188__setup("relax_domain_level=", setup_relax_domain_level);
1189
1190static void set_domain_attribute(struct sched_domain *sd,
1191 struct sched_domain_attr *attr)
1192{
1193 int request;
1194
1195 if (!attr || attr->relax_domain_level < 0) {
1196 if (default_relax_domain_level < 0)
1197 return;
1198 else
1199 request = default_relax_domain_level;
1200 } else
1201 request = attr->relax_domain_level;
1202 if (request < sd->level) {
1203 /* Turn off idle balance on this domain: */
1204 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
1205 } else {
1206 /* Turn on idle balance on this domain: */
1207 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
1208 }
1209}
1210
1211static void __sdt_free(const struct cpumask *cpu_map);
1212static int __sdt_alloc(const struct cpumask *cpu_map);
1213
1214static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
1215 const struct cpumask *cpu_map)
1216{
1217 switch (what) {
1218 case sa_rootdomain:
1219 if (!atomic_read(&d->rd->refcount))
1220 free_rootdomain(&d->rd->rcu);
1221 /* Fall through */
1222 case sa_sd:
1223 free_percpu(d->sd);
1224 /* Fall through */
1225 case sa_sd_storage:
1226 __sdt_free(cpu_map);
1227 /* Fall through */
1228 case sa_none:
1229 break;
1230 }
1231}
1232
1233static enum s_alloc
1234__visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map)
1235{
1236 memset(d, 0, sizeof(*d));
1237
1238 if (__sdt_alloc(cpu_map))
1239 return sa_sd_storage;
1240 d->sd = alloc_percpu(struct sched_domain *);
1241 if (!d->sd)
1242 return sa_sd_storage;
1243 d->rd = alloc_rootdomain();
1244 if (!d->rd)
1245 return sa_sd;
1246
1247 return sa_rootdomain;
1248}
1249
1250/*
1251 * NULL the sd_data elements we've used to build the sched_domain and
1252 * sched_group structure so that the subsequent __free_domain_allocs()
1253 * will not free the data we're using.
1254 */
1255static void claim_allocations(int cpu, struct sched_domain *sd)
1256{
1257 struct sd_data *sdd = sd->private;
1258
1259 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
1260 *per_cpu_ptr(sdd->sd, cpu) = NULL;
1261
1262 if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
1263 *per_cpu_ptr(sdd->sds, cpu) = NULL;
1264
1265 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
1266 *per_cpu_ptr(sdd->sg, cpu) = NULL;
1267
1268 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
1269 *per_cpu_ptr(sdd->sgc, cpu) = NULL;
1270}
1271
1272#ifdef CONFIG_NUMA
1273enum numa_topology_type sched_numa_topology_type;
1274
1275static int sched_domains_numa_levels;
1276static int sched_domains_curr_level;
1277
1278int sched_max_numa_distance;
1279static int *sched_domains_numa_distance;
1280static struct cpumask ***sched_domains_numa_masks;
1281#endif
1282
1283/*
1284 * SD_flags allowed in topology descriptions.
1285 *
1286 * These flags are purely descriptive of the topology and do not prescribe
1287 * behaviour. Behaviour is artificial and mapped in the below sd_init()
1288 * function:
1289 *
1290 * SD_SHARE_CPUCAPACITY - describes SMT topologies
1291 * SD_SHARE_PKG_RESOURCES - describes shared caches
1292 * SD_NUMA - describes NUMA topologies
1293 * SD_SHARE_POWERDOMAIN - describes shared power domain
1294 *
1295 * Odd one out, which beside describing the topology has a quirk also
1296 * prescribes the desired behaviour that goes along with it:
1297 *
1298 * SD_ASYM_PACKING - describes SMT quirks
1299 */
1300#define TOPOLOGY_SD_FLAGS \
1301 (SD_SHARE_CPUCAPACITY | \
1302 SD_SHARE_PKG_RESOURCES | \
1303 SD_NUMA | \
1304 SD_ASYM_PACKING | \
1305 SD_SHARE_POWERDOMAIN)
1306
1307static struct sched_domain *
1308sd_init(struct sched_domain_topology_level *tl,
1309 const struct cpumask *cpu_map,
1310 struct sched_domain *child, int dflags, int cpu)
1311{
1312 struct sd_data *sdd = &tl->data;
1313 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
1314 int sd_id, sd_weight, sd_flags = 0;
1315
1316#ifdef CONFIG_NUMA
1317 /*
1318 * Ugly hack to pass state to sd_numa_mask()...
1319 */
1320 sched_domains_curr_level = tl->numa_level;
1321#endif
1322
1323 sd_weight = cpumask_weight(tl->mask(cpu));
1324
1325 if (tl->sd_flags)
1326 sd_flags = (*tl->sd_flags)();
1327 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
1328 "wrong sd_flags in topology description\n"))
1329 sd_flags &= ~TOPOLOGY_SD_FLAGS;
1330
1331 /* Apply detected topology flags */
1332 sd_flags |= dflags;
1333
1334 *sd = (struct sched_domain){
1335 .min_interval = sd_weight,
1336 .max_interval = 2*sd_weight,
1337 .busy_factor = 32,
1338 .imbalance_pct = 125,
1339
1340 .cache_nice_tries = 0,
1341 .busy_idx = 0,
1342 .idle_idx = 0,
1343 .newidle_idx = 0,
1344 .wake_idx = 0,
1345 .forkexec_idx = 0,
1346
1347 .flags = 1*SD_LOAD_BALANCE
1348 | 1*SD_BALANCE_NEWIDLE
1349 | 1*SD_BALANCE_EXEC
1350 | 1*SD_BALANCE_FORK
1351 | 0*SD_BALANCE_WAKE
1352 | 1*SD_WAKE_AFFINE
1353 | 0*SD_SHARE_CPUCAPACITY
1354 | 0*SD_SHARE_PKG_RESOURCES
1355 | 0*SD_SERIALIZE
1356 | 1*SD_PREFER_SIBLING
1357 | 0*SD_NUMA
1358 | sd_flags
1359 ,
1360
1361 .last_balance = jiffies,
1362 .balance_interval = sd_weight,
1363 .max_newidle_lb_cost = 0,
1364 .next_decay_max_lb_cost = jiffies,
1365 .child = child,
1366#ifdef CONFIG_SCHED_DEBUG
1367 .name = tl->name,
1368#endif
1369 };
1370
1371 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
1372 sd_id = cpumask_first(sched_domain_span(sd));
1373
1374 /*
1375 * Convert topological properties into behaviour.
1376 */
1377
1378 if (sd->flags & SD_ASYM_CPUCAPACITY) {
1379 struct sched_domain *t = sd;
1380
1381 /*
1382 * Don't attempt to spread across CPUs of different capacities.
1383 */
1384 if (sd->child)
1385 sd->child->flags &= ~SD_PREFER_SIBLING;
1386
1387 for_each_lower_domain(t)
1388 t->flags |= SD_BALANCE_WAKE;
1389 }
1390
1391 if (sd->flags & SD_SHARE_CPUCAPACITY) {
1392 sd->imbalance_pct = 110;
1393
1394 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
1395 sd->imbalance_pct = 117;
1396 sd->cache_nice_tries = 1;
1397 sd->busy_idx = 2;
1398
1399#ifdef CONFIG_NUMA
1400 } else if (sd->flags & SD_NUMA) {
1401 sd->cache_nice_tries = 2;
1402 sd->busy_idx = 3;
1403 sd->idle_idx = 2;
1404
1405 sd->flags &= ~SD_PREFER_SIBLING;
1406 sd->flags |= SD_SERIALIZE;
1407 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
1408 sd->flags &= ~(SD_BALANCE_EXEC |
1409 SD_BALANCE_FORK |
1410 SD_WAKE_AFFINE);
1411 }
1412
1413#endif
1414 } else {
1415 sd->cache_nice_tries = 1;
1416 sd->busy_idx = 2;
1417 sd->idle_idx = 1;
1418 }
1419
1420 /*
1421 * For all levels sharing cache; connect a sched_domain_shared
1422 * instance.
1423 */
1424 if (sd->flags & SD_SHARE_PKG_RESOURCES) {
1425 sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
1426 atomic_inc(&sd->shared->ref);
1427 atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
1428 }
1429
1430 sd->private = sdd;
1431
1432 return sd;
1433}
1434
1435/*
1436 * Topology list, bottom-up.
1437 */
1438static struct sched_domain_topology_level default_topology[] = {
1439#ifdef CONFIG_SCHED_SMT
1440 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
1441#endif
1442#ifdef CONFIG_SCHED_MC
1443 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
1444#endif
1445 { cpu_cpu_mask, SD_INIT_NAME(DIE) },
1446 { NULL, },
1447};
1448
1449static struct sched_domain_topology_level *sched_domain_topology =
1450 default_topology;
1451
1452#define for_each_sd_topology(tl) \
1453 for (tl = sched_domain_topology; tl->mask; tl++)
1454
1455void set_sched_topology(struct sched_domain_topology_level *tl)
1456{
1457 if (WARN_ON_ONCE(sched_smp_initialized))
1458 return;
1459
1460 sched_domain_topology = tl;
1461}
1462
1463#ifdef CONFIG_NUMA
1464
1465static const struct cpumask *sd_numa_mask(int cpu)
1466{
1467 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
1468}
1469
1470static void sched_numa_warn(const char *str)
1471{
1472 static int done = false;
1473 int i,j;
1474
1475 if (done)
1476 return;
1477
1478 done = true;
1479
1480 printk(KERN_WARNING "ERROR: %s\n\n", str);
1481
1482 for (i = 0; i < nr_node_ids; i++) {
1483 printk(KERN_WARNING " ");
1484 for (j = 0; j < nr_node_ids; j++)
1485 printk(KERN_CONT "%02d ", node_distance(i,j));
1486 printk(KERN_CONT "\n");
1487 }
1488 printk(KERN_WARNING "\n");
1489}
1490
1491bool find_numa_distance(int distance)
1492{
1493 int i;
1494
1495 if (distance == node_distance(0, 0))
1496 return true;
1497
1498 for (i = 0; i < sched_domains_numa_levels; i++) {
1499 if (sched_domains_numa_distance[i] == distance)
1500 return true;
1501 }
1502
1503 return false;
1504}
1505
1506/*
1507 * A system can have three types of NUMA topology:
1508 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
1509 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
1510 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
1511 *
1512 * The difference between a glueless mesh topology and a backplane
1513 * topology lies in whether communication between not directly
1514 * connected nodes goes through intermediary nodes (where programs
1515 * could run), or through backplane controllers. This affects
1516 * placement of programs.
1517 *
1518 * The type of topology can be discerned with the following tests:
1519 * - If the maximum distance between any nodes is 1 hop, the system
1520 * is directly connected.
1521 * - If for two nodes A and B, located N > 1 hops away from each other,
1522 * there is an intermediary node C, which is < N hops away from both
1523 * nodes A and B, the system is a glueless mesh.
1524 */
1525static void init_numa_topology_type(void)
1526{
1527 int a, b, c, n;
1528
1529 n = sched_max_numa_distance;
1530
1531 if (sched_domains_numa_levels <= 2) {
1532 sched_numa_topology_type = NUMA_DIRECT;
1533 return;
1534 }
1535
1536 for_each_online_node(a) {
1537 for_each_online_node(b) {
1538 /* Find two nodes furthest removed from each other. */
1539 if (node_distance(a, b) < n)
1540 continue;
1541
1542 /* Is there an intermediary node between a and b? */
1543 for_each_online_node(c) {
1544 if (node_distance(a, c) < n &&
1545 node_distance(b, c) < n) {
1546 sched_numa_topology_type =
1547 NUMA_GLUELESS_MESH;
1548 return;
1549 }
1550 }
1551
1552 sched_numa_topology_type = NUMA_BACKPLANE;
1553 return;
1554 }
1555 }
1556}
1557
1558void sched_init_numa(void)
1559{
1560 int next_distance, curr_distance = node_distance(0, 0);
1561 struct sched_domain_topology_level *tl;
1562 int level = 0;
1563 int i, j, k;
1564
1565 sched_domains_numa_distance = kzalloc(sizeof(int) * (nr_node_ids + 1), GFP_KERNEL);
1566 if (!sched_domains_numa_distance)
1567 return;
1568
1569 /* Includes NUMA identity node at level 0. */
1570 sched_domains_numa_distance[level++] = curr_distance;
1571 sched_domains_numa_levels = level;
1572
1573 /*
1574 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
1575 * unique distances in the node_distance() table.
1576 *
1577 * Assumes node_distance(0,j) includes all distances in
1578 * node_distance(i,j) in order to avoid cubic time.
1579 */
1580 next_distance = curr_distance;
1581 for (i = 0; i < nr_node_ids; i++) {
1582 for (j = 0; j < nr_node_ids; j++) {
1583 for (k = 0; k < nr_node_ids; k++) {
1584 int distance = node_distance(i, k);
1585
1586 if (distance > curr_distance &&
1587 (distance < next_distance ||
1588 next_distance == curr_distance))
1589 next_distance = distance;
1590
1591 /*
1592 * While not a strong assumption it would be nice to know
1593 * about cases where if node A is connected to B, B is not
1594 * equally connected to A.
1595 */
1596 if (sched_debug() && node_distance(k, i) != distance)
1597 sched_numa_warn("Node-distance not symmetric");
1598
1599 if (sched_debug() && i && !find_numa_distance(distance))
1600 sched_numa_warn("Node-0 not representative");
1601 }
1602 if (next_distance != curr_distance) {
1603 sched_domains_numa_distance[level++] = next_distance;
1604 sched_domains_numa_levels = level;
1605 curr_distance = next_distance;
1606 } else break;
1607 }
1608
1609 /*
1610 * In case of sched_debug() we verify the above assumption.
1611 */
1612 if (!sched_debug())
1613 break;
1614 }
1615
1616 /*
1617 * 'level' contains the number of unique distances
1618 *
1619 * The sched_domains_numa_distance[] array includes the actual distance
1620 * numbers.
1621 */
1622
1623 /*
1624 * Here, we should temporarily reset sched_domains_numa_levels to 0.
1625 * If it fails to allocate memory for array sched_domains_numa_masks[][],
1626 * the array will contain less then 'level' members. This could be
1627 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
1628 * in other functions.
1629 *
1630 * We reset it to 'level' at the end of this function.
1631 */
1632 sched_domains_numa_levels = 0;
1633
1634 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
1635 if (!sched_domains_numa_masks)
1636 return;
1637
1638 /*
1639 * Now for each level, construct a mask per node which contains all
1640 * CPUs of nodes that are that many hops away from us.
1641 */
1642 for (i = 0; i < level; i++) {
1643 sched_domains_numa_masks[i] =
1644 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
1645 if (!sched_domains_numa_masks[i])
1646 return;
1647
1648 for (j = 0; j < nr_node_ids; j++) {
1649 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
1650 if (!mask)
1651 return;
1652
1653 sched_domains_numa_masks[i][j] = mask;
1654
1655 for_each_node(k) {
1656 if (node_distance(j, k) > sched_domains_numa_distance[i])
1657 continue;
1658
1659 cpumask_or(mask, mask, cpumask_of_node(k));
1660 }
1661 }
1662 }
1663
1664 /* Compute default topology size */
1665 for (i = 0; sched_domain_topology[i].mask; i++);
1666
1667 tl = kzalloc((i + level + 1) *
1668 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
1669 if (!tl)
1670 return;
1671
1672 /*
1673 * Copy the default topology bits..
1674 */
1675 for (i = 0; sched_domain_topology[i].mask; i++)
1676 tl[i] = sched_domain_topology[i];
1677
1678 /*
1679 * Add the NUMA identity distance, aka single NODE.
1680 */
1681 tl[i++] = (struct sched_domain_topology_level){
1682 .mask = sd_numa_mask,
1683 .numa_level = 0,
1684 SD_INIT_NAME(NODE)
1685 };
1686
1687 /*
1688 * .. and append 'j' levels of NUMA goodness.
1689 */
1690 for (j = 1; j < level; i++, j++) {
1691 tl[i] = (struct sched_domain_topology_level){
1692 .mask = sd_numa_mask,
1693 .sd_flags = cpu_numa_flags,
1694 .flags = SDTL_OVERLAP,
1695 .numa_level = j,
1696 SD_INIT_NAME(NUMA)
1697 };
1698 }
1699
1700 sched_domain_topology = tl;
1701
1702 sched_domains_numa_levels = level;
1703 sched_max_numa_distance = sched_domains_numa_distance[level - 1];
1704
1705 init_numa_topology_type();
1706}
1707
1708void sched_domains_numa_masks_set(unsigned int cpu)
1709{
1710 int node = cpu_to_node(cpu);
1711 int i, j;
1712
1713 for (i = 0; i < sched_domains_numa_levels; i++) {
1714 for (j = 0; j < nr_node_ids; j++) {
1715 if (node_distance(j, node) <= sched_domains_numa_distance[i])
1716 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
1717 }
1718 }
1719}
1720
1721void sched_domains_numa_masks_clear(unsigned int cpu)
1722{
1723 int i, j;
1724
1725 for (i = 0; i < sched_domains_numa_levels; i++) {
1726 for (j = 0; j < nr_node_ids; j++)
1727 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
1728 }
1729}
1730
1731#endif /* CONFIG_NUMA */
1732
1733static int __sdt_alloc(const struct cpumask *cpu_map)
1734{
1735 struct sched_domain_topology_level *tl;
1736 int j;
1737
1738 for_each_sd_topology(tl) {
1739 struct sd_data *sdd = &tl->data;
1740
1741 sdd->sd = alloc_percpu(struct sched_domain *);
1742 if (!sdd->sd)
1743 return -ENOMEM;
1744
1745 sdd->sds = alloc_percpu(struct sched_domain_shared *);
1746 if (!sdd->sds)
1747 return -ENOMEM;
1748
1749 sdd->sg = alloc_percpu(struct sched_group *);
1750 if (!sdd->sg)
1751 return -ENOMEM;
1752
1753 sdd->sgc = alloc_percpu(struct sched_group_capacity *);
1754 if (!sdd->sgc)
1755 return -ENOMEM;
1756
1757 for_each_cpu(j, cpu_map) {
1758 struct sched_domain *sd;
1759 struct sched_domain_shared *sds;
1760 struct sched_group *sg;
1761 struct sched_group_capacity *sgc;
1762
1763 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
1764 GFP_KERNEL, cpu_to_node(j));
1765 if (!sd)
1766 return -ENOMEM;
1767
1768 *per_cpu_ptr(sdd->sd, j) = sd;
1769
1770 sds = kzalloc_node(sizeof(struct sched_domain_shared),
1771 GFP_KERNEL, cpu_to_node(j));
1772 if (!sds)
1773 return -ENOMEM;
1774
1775 *per_cpu_ptr(sdd->sds, j) = sds;
1776
1777 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
1778 GFP_KERNEL, cpu_to_node(j));
1779 if (!sg)
1780 return -ENOMEM;
1781
1782 sg->next = sg;
1783
1784 *per_cpu_ptr(sdd->sg, j) = sg;
1785
1786 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
1787 GFP_KERNEL, cpu_to_node(j));
1788 if (!sgc)
1789 return -ENOMEM;
1790
1791#ifdef CONFIG_SCHED_DEBUG
1792 sgc->id = j;
1793#endif
1794
1795 *per_cpu_ptr(sdd->sgc, j) = sgc;
1796 }
1797 }
1798
1799 return 0;
1800}
1801
1802static void __sdt_free(const struct cpumask *cpu_map)
1803{
1804 struct sched_domain_topology_level *tl;
1805 int j;
1806
1807 for_each_sd_topology(tl) {
1808 struct sd_data *sdd = &tl->data;
1809
1810 for_each_cpu(j, cpu_map) {
1811 struct sched_domain *sd;
1812
1813 if (sdd->sd) {
1814 sd = *per_cpu_ptr(sdd->sd, j);
1815 if (sd && (sd->flags & SD_OVERLAP))
1816 free_sched_groups(sd->groups, 0);
1817 kfree(*per_cpu_ptr(sdd->sd, j));
1818 }
1819
1820 if (sdd->sds)
1821 kfree(*per_cpu_ptr(sdd->sds, j));
1822 if (sdd->sg)
1823 kfree(*per_cpu_ptr(sdd->sg, j));
1824 if (sdd->sgc)
1825 kfree(*per_cpu_ptr(sdd->sgc, j));
1826 }
1827 free_percpu(sdd->sd);
1828 sdd->sd = NULL;
1829 free_percpu(sdd->sds);
1830 sdd->sds = NULL;
1831 free_percpu(sdd->sg);
1832 sdd->sg = NULL;
1833 free_percpu(sdd->sgc);
1834 sdd->sgc = NULL;
1835 }
1836}
1837
1838static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
1839 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
1840 struct sched_domain *child, int dflags, int cpu)
1841{
1842 struct sched_domain *sd = sd_init(tl, cpu_map, child, dflags, cpu);
1843
1844 if (child) {
1845 sd->level = child->level + 1;
1846 sched_domain_level_max = max(sched_domain_level_max, sd->level);
1847 child->parent = sd;
1848
1849 if (!cpumask_subset(sched_domain_span(child),
1850 sched_domain_span(sd))) {
1851 pr_err("BUG: arch topology borken\n");
1852#ifdef CONFIG_SCHED_DEBUG
1853 pr_err(" the %s domain not a subset of the %s domain\n",
1854 child->name, sd->name);
1855#endif
1856 /* Fixup, ensure @sd has at least @child CPUs. */
1857 cpumask_or(sched_domain_span(sd),
1858 sched_domain_span(sd),
1859 sched_domain_span(child));
1860 }
1861
1862 }
1863 set_domain_attribute(sd, attr);
1864
1865 return sd;
1866}
1867
1868/*
1869 * Find the sched_domain_topology_level where all CPU capacities are visible
1870 * for all CPUs.
1871 */
1872static struct sched_domain_topology_level
1873*asym_cpu_capacity_level(const struct cpumask *cpu_map)
1874{
1875 int i, j, asym_level = 0;
1876 bool asym = false;
1877 struct sched_domain_topology_level *tl, *asym_tl = NULL;
1878 unsigned long cap;
1879
1880 /* Is there any asymmetry? */
1881 cap = arch_scale_cpu_capacity(NULL, cpumask_first(cpu_map));
1882
1883 for_each_cpu(i, cpu_map) {
1884 if (arch_scale_cpu_capacity(NULL, i) != cap) {
1885 asym = true;
1886 break;
1887 }
1888 }
1889
1890 if (!asym)
1891 return NULL;
1892
1893 /*
1894 * Examine topology from all CPU's point of views to detect the lowest
1895 * sched_domain_topology_level where a highest capacity CPU is visible
1896 * to everyone.
1897 */
1898 for_each_cpu(i, cpu_map) {
1899 unsigned long max_capacity = arch_scale_cpu_capacity(NULL, i);
1900 int tl_id = 0;
1901
1902 for_each_sd_topology(tl) {
1903 if (tl_id < asym_level)
1904 goto next_level;
1905
1906 for_each_cpu_and(j, tl->mask(i), cpu_map) {
1907 unsigned long capacity;
1908
1909 capacity = arch_scale_cpu_capacity(NULL, j);
1910
1911 if (capacity <= max_capacity)
1912 continue;
1913
1914 max_capacity = capacity;
1915 asym_level = tl_id;
1916 asym_tl = tl;
1917 }
1918next_level:
1919 tl_id++;
1920 }
1921 }
1922
1923 return asym_tl;
1924}
1925
1926
1927/*
1928 * Build sched domains for a given set of CPUs and attach the sched domains
1929 * to the individual CPUs
1930 */
1931static int
1932build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr)
1933{
1934 enum s_alloc alloc_state;
1935 struct sched_domain *sd;
1936 struct s_data d;
1937 struct rq *rq = NULL;
1938 int i, ret = -ENOMEM;
1939 struct sched_domain_topology_level *tl_asym;
1940 bool has_asym = false;
1941
1942 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
1943 if (alloc_state != sa_rootdomain)
1944 goto error;
1945
1946 tl_asym = asym_cpu_capacity_level(cpu_map);
1947
1948 /* Set up domains for CPUs specified by the cpu_map: */
1949 for_each_cpu(i, cpu_map) {
1950 struct sched_domain_topology_level *tl;
1951
1952 sd = NULL;
1953 for_each_sd_topology(tl) {
1954 int dflags = 0;
1955
1956 if (tl == tl_asym) {
1957 dflags |= SD_ASYM_CPUCAPACITY;
1958 has_asym = true;
1959 }
1960
1961 sd = build_sched_domain(tl, cpu_map, attr, sd, dflags, i);
1962
1963 if (tl == sched_domain_topology)
1964 *per_cpu_ptr(d.sd, i) = sd;
1965 if (tl->flags & SDTL_OVERLAP)
1966 sd->flags |= SD_OVERLAP;
1967 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
1968 break;
1969 }
1970 }
1971
1972 /* Build the groups for the domains */
1973 for_each_cpu(i, cpu_map) {
1974 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
1975 sd->span_weight = cpumask_weight(sched_domain_span(sd));
1976 if (sd->flags & SD_OVERLAP) {
1977 if (build_overlap_sched_groups(sd, i))
1978 goto error;
1979 } else {
1980 if (build_sched_groups(sd, i))
1981 goto error;
1982 }
1983 }
1984 }
1985
1986 /* Calculate CPU capacity for physical packages and nodes */
1987 for (i = nr_cpumask_bits-1; i >= 0; i--) {
1988 if (!cpumask_test_cpu(i, cpu_map))
1989 continue;
1990
1991 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
1992 claim_allocations(i, sd);
1993 init_sched_groups_capacity(i, sd);
1994 }
1995 }
1996
1997 /* Attach the domains */
1998 rcu_read_lock();
1999 for_each_cpu(i, cpu_map) {
2000 rq = cpu_rq(i);
2001 sd = *per_cpu_ptr(d.sd, i);
2002
2003 /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
2004 if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
2005 WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
2006
2007 cpu_attach_domain(sd, d.rd, i);
2008 }
2009 rcu_read_unlock();
2010
2011 if (has_asym)
2012 static_branch_enable_cpuslocked(&sched_asym_cpucapacity);
2013
2014 if (rq && sched_debug_enabled) {
2015 pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
2016 cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
2017 }
2018
2019 ret = 0;
2020error:
2021 __free_domain_allocs(&d, alloc_state, cpu_map);
2022
2023 return ret;
2024}
2025
2026/* Current sched domains: */
2027static cpumask_var_t *doms_cur;
2028
2029/* Number of sched domains in 'doms_cur': */
2030static int ndoms_cur;
2031
2032/* Attribues of custom domains in 'doms_cur' */
2033static struct sched_domain_attr *dattr_cur;
2034
2035/*
2036 * Special case: If a kmalloc() of a doms_cur partition (array of
2037 * cpumask) fails, then fallback to a single sched domain,
2038 * as determined by the single cpumask fallback_doms.
2039 */
2040static cpumask_var_t fallback_doms;
2041
2042/*
2043 * arch_update_cpu_topology lets virtualized architectures update the
2044 * CPU core maps. It is supposed to return 1 if the topology changed
2045 * or 0 if it stayed the same.
2046 */
2047int __weak arch_update_cpu_topology(void)
2048{
2049 return 0;
2050}
2051
2052cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
2053{
2054 int i;
2055 cpumask_var_t *doms;
2056
2057 doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL);
2058 if (!doms)
2059 return NULL;
2060 for (i = 0; i < ndoms; i++) {
2061 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
2062 free_sched_domains(doms, i);
2063 return NULL;
2064 }
2065 }
2066 return doms;
2067}
2068
2069void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
2070{
2071 unsigned int i;
2072 for (i = 0; i < ndoms; i++)
2073 free_cpumask_var(doms[i]);
2074 kfree(doms);
2075}
2076
2077/*
2078 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
2079 * For now this just excludes isolated CPUs, but could be used to
2080 * exclude other special cases in the future.
2081 */
2082int sched_init_domains(const struct cpumask *cpu_map)
2083{
2084 int err;
2085
2086 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL);
2087 zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL);
2088 zalloc_cpumask_var(&fallback_doms, GFP_KERNEL);
2089
2090 arch_update_cpu_topology();
2091 ndoms_cur = 1;
2092 doms_cur = alloc_sched_domains(ndoms_cur);
2093 if (!doms_cur)
2094 doms_cur = &fallback_doms;
2095 cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN));
2096 err = build_sched_domains(doms_cur[0], NULL);
2097 register_sched_domain_sysctl();
2098
2099 return err;
2100}
2101
2102/*
2103 * Detach sched domains from a group of CPUs specified in cpu_map
2104 * These CPUs will now be attached to the NULL domain
2105 */
2106static void detach_destroy_domains(const struct cpumask *cpu_map)
2107{
2108 int i;
2109
2110 rcu_read_lock();
2111 for_each_cpu(i, cpu_map)
2112 cpu_attach_domain(NULL, &def_root_domain, i);
2113 rcu_read_unlock();
2114}
2115
2116/* handle null as "default" */
2117static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
2118 struct sched_domain_attr *new, int idx_new)
2119{
2120 struct sched_domain_attr tmp;
2121
2122 /* Fast path: */
2123 if (!new && !cur)
2124 return 1;
2125
2126 tmp = SD_ATTR_INIT;
2127
2128 return !memcmp(cur ? (cur + idx_cur) : &tmp,
2129 new ? (new + idx_new) : &tmp,
2130 sizeof(struct sched_domain_attr));
2131}
2132
2133/*
2134 * Partition sched domains as specified by the 'ndoms_new'
2135 * cpumasks in the array doms_new[] of cpumasks. This compares
2136 * doms_new[] to the current sched domain partitioning, doms_cur[].
2137 * It destroys each deleted domain and builds each new domain.
2138 *
2139 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
2140 * The masks don't intersect (don't overlap.) We should setup one
2141 * sched domain for each mask. CPUs not in any of the cpumasks will
2142 * not be load balanced. If the same cpumask appears both in the
2143 * current 'doms_cur' domains and in the new 'doms_new', we can leave
2144 * it as it is.
2145 *
2146 * The passed in 'doms_new' should be allocated using
2147 * alloc_sched_domains. This routine takes ownership of it and will
2148 * free_sched_domains it when done with it. If the caller failed the
2149 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
2150 * and partition_sched_domains() will fallback to the single partition
2151 * 'fallback_doms', it also forces the domains to be rebuilt.
2152 *
2153 * If doms_new == NULL it will be replaced with cpu_online_mask.
2154 * ndoms_new == 0 is a special case for destroying existing domains,
2155 * and it will not create the default domain.
2156 *
2157 * Call with hotplug lock held
2158 */
2159void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
2160 struct sched_domain_attr *dattr_new)
2161{
2162 bool __maybe_unused has_eas = false;
2163 int i, j, n;
2164 int new_topology;
2165
2166 mutex_lock(&sched_domains_mutex);
2167
2168 /* Always unregister in case we don't destroy any domains: */
2169 unregister_sched_domain_sysctl();
2170
2171 /* Let the architecture update CPU core mappings: */
2172 new_topology = arch_update_cpu_topology();
2173
2174 if (!doms_new) {
2175 WARN_ON_ONCE(dattr_new);
2176 n = 0;
2177 doms_new = alloc_sched_domains(1);
2178 if (doms_new) {
2179 n = 1;
2180 cpumask_and(doms_new[0], cpu_active_mask,
2181 housekeeping_cpumask(HK_FLAG_DOMAIN));
2182 }
2183 } else {
2184 n = ndoms_new;
2185 }
2186
2187 /* Destroy deleted domains: */
2188 for (i = 0; i < ndoms_cur; i++) {
2189 for (j = 0; j < n && !new_topology; j++) {
2190 if (cpumask_equal(doms_cur[i], doms_new[j]) &&
2191 dattrs_equal(dattr_cur, i, dattr_new, j))
2192 goto match1;
2193 }
2194 /* No match - a current sched domain not in new doms_new[] */
2195 detach_destroy_domains(doms_cur[i]);
2196match1:
2197 ;
2198 }
2199
2200 n = ndoms_cur;
2201 if (!doms_new) {
2202 n = 0;
2203 doms_new = &fallback_doms;
2204 cpumask_and(doms_new[0], cpu_active_mask,
2205 housekeeping_cpumask(HK_FLAG_DOMAIN));
2206 }
2207
2208 /* Build new domains: */
2209 for (i = 0; i < ndoms_new; i++) {
2210 for (j = 0; j < n && !new_topology; j++) {
2211 if (cpumask_equal(doms_new[i], doms_cur[j]) &&
2212 dattrs_equal(dattr_new, i, dattr_cur, j))
2213 goto match2;
2214 }
2215 /* No match - add a new doms_new */
2216 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
2217match2:
2218 ;
2219 }
2220
2221#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
2222 /* Build perf. domains: */
2223 for (i = 0; i < ndoms_new; i++) {
2224 for (j = 0; j < n && !sched_energy_update; j++) {
2225 if (cpumask_equal(doms_new[i], doms_cur[j]) &&
2226 cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) {
2227 has_eas = true;
2228 goto match3;
2229 }
2230 }
2231 /* No match - add perf. domains for a new rd */
2232 has_eas |= build_perf_domains(doms_new[i]);
2233match3:
2234 ;
2235 }
2236 sched_energy_set(has_eas);
2237#endif
2238
2239 /* Remember the new sched domains: */
2240 if (doms_cur != &fallback_doms)
2241 free_sched_domains(doms_cur, ndoms_cur);
2242
2243 kfree(dattr_cur);
2244 doms_cur = doms_new;
2245 dattr_cur = dattr_new;
2246 ndoms_cur = ndoms_new;
2247
2248 register_sched_domain_sysctl();
2249
2250 mutex_unlock(&sched_domains_mutex);
2251}
2252