Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Scheduler topology setup/handling methods
4 : */
5 : #include "sched.h"
6 :
7 : DEFINE_MUTEX(sched_domains_mutex);
8 :
9 : /* Protected by sched_domains_mutex: */
10 : static cpumask_var_t sched_domains_tmpmask;
11 : static cpumask_var_t sched_domains_tmpmask2;
12 :
13 : #ifdef CONFIG_SCHED_DEBUG
14 :
15 : static int __init sched_debug_setup(char *str)
16 : {
17 : sched_debug_enabled = true;
18 :
19 : return 0;
20 : }
21 : early_param("sched_debug", sched_debug_setup);
22 :
23 : static inline bool sched_debug(void)
24 : {
25 : return sched_debug_enabled;
26 : }
27 :
28 : #define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name },
29 : const struct sd_flag_debug sd_flag_debug[] = {
30 : #include <linux/sched/sd_flags.h>
31 : };
32 : #undef SD_FLAG
33 :
34 : static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
35 : struct cpumask *groupmask)
36 : {
37 : struct sched_group *group = sd->groups;
38 : unsigned long flags = sd->flags;
39 : unsigned int idx;
40 :
41 : cpumask_clear(groupmask);
42 :
43 : printk(KERN_DEBUG "%*s domain-%d: ", level, "", level);
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 : for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
55 : unsigned int flag = BIT(idx);
56 : unsigned int meta_flags = sd_flag_debug[idx].meta_flags;
57 :
58 : if ((meta_flags & SDF_SHARED_CHILD) && sd->child &&
59 : !(sd->child->flags & flag))
60 : printk(KERN_ERR "ERROR: flag %s set here but not in child\n",
61 : sd_flag_debug[idx].name);
62 :
63 : if ((meta_flags & SDF_SHARED_PARENT) && sd->parent &&
64 : !(sd->parent->flags & flag))
65 : printk(KERN_ERR "ERROR: flag %s set here but not in parent\n",
66 : sd_flag_debug[idx].name);
67 : }
68 :
69 : printk(KERN_DEBUG "%*s groups:", level + 1, "");
70 : do {
71 : if (!group) {
72 : printk("\n");
73 : printk(KERN_ERR "ERROR: group is NULL\n");
74 : break;
75 : }
76 :
77 : if (!cpumask_weight(sched_group_span(group))) {
78 : printk(KERN_CONT "\n");
79 : printk(KERN_ERR "ERROR: empty group\n");
80 : break;
81 : }
82 :
83 : if (!(sd->flags & SD_OVERLAP) &&
84 : cpumask_intersects(groupmask, sched_group_span(group))) {
85 : printk(KERN_CONT "\n");
86 : printk(KERN_ERR "ERROR: repeated CPUs\n");
87 : break;
88 : }
89 :
90 : cpumask_or(groupmask, groupmask, sched_group_span(group));
91 :
92 : printk(KERN_CONT " %d:{ span=%*pbl",
93 : group->sgc->id,
94 : cpumask_pr_args(sched_group_span(group)));
95 :
96 : if ((sd->flags & SD_OVERLAP) &&
97 : !cpumask_equal(group_balance_mask(group), sched_group_span(group))) {
98 : printk(KERN_CONT " mask=%*pbl",
99 : cpumask_pr_args(group_balance_mask(group)));
100 : }
101 :
102 : if (group->sgc->capacity != SCHED_CAPACITY_SCALE)
103 : printk(KERN_CONT " cap=%lu", group->sgc->capacity);
104 :
105 : if (group == sd->groups && sd->child &&
106 : !cpumask_equal(sched_domain_span(sd->child),
107 : sched_group_span(group))) {
108 : printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n");
109 : }
110 :
111 : printk(KERN_CONT " }");
112 :
113 : group = group->next;
114 :
115 : if (group != sd->groups)
116 : printk(KERN_CONT ",");
117 :
118 : } while (group != sd->groups);
119 : printk(KERN_CONT "\n");
120 :
121 : if (!cpumask_equal(sched_domain_span(sd), groupmask))
122 : printk(KERN_ERR "ERROR: groups don't span domain->span\n");
123 :
124 : if (sd->parent &&
125 : !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
126 : printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
127 : return 0;
128 : }
129 :
130 : static void sched_domain_debug(struct sched_domain *sd, int cpu)
131 : {
132 : int level = 0;
133 :
134 : if (!sched_debug_enabled)
135 : return;
136 :
137 : if (!sd) {
138 : printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
139 : return;
140 : }
141 :
142 : printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu);
143 :
144 : for (;;) {
145 : if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
146 : break;
147 : level++;
148 : sd = sd->parent;
149 : if (!sd)
150 : break;
151 : }
152 : }
153 : #else /* !CONFIG_SCHED_DEBUG */
154 :
155 : # define sched_debug_enabled 0
156 : # define sched_domain_debug(sd, cpu) do { } while (0)
157 1 : static inline bool sched_debug(void)
158 : {
159 1 : return false;
160 : }
161 : #endif /* CONFIG_SCHED_DEBUG */
162 :
163 : /* Generate a mask of SD flags with the SDF_NEEDS_GROUPS metaflag */
164 : #define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_NEEDS_GROUPS)) |
165 : static const unsigned int SD_DEGENERATE_GROUPS_MASK =
166 : #include <linux/sched/sd_flags.h>
167 : 0;
168 : #undef SD_FLAG
169 :
170 12 : static int sd_degenerate(struct sched_domain *sd)
171 : {
172 12 : if (cpumask_weight(sched_domain_span(sd)) == 1)
173 : return 1;
174 :
175 : /* Following flags need at least 2 groups */
176 4 : if ((sd->flags & SD_DEGENERATE_GROUPS_MASK) &&
177 4 : (sd->groups != sd->groups->next))
178 : return 0;
179 :
180 : /* Following flags don't use groups */
181 0 : if (sd->flags & (SD_WAKE_AFFINE))
182 0 : return 0;
183 :
184 : return 1;
185 : }
186 :
187 : static int
188 8 : sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
189 : {
190 8 : unsigned long cflags = sd->flags, pflags = parent->flags;
191 :
192 8 : if (sd_degenerate(parent))
193 : return 1;
194 :
195 4 : if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
196 : return 0;
197 :
198 : /* Flags needing groups don't count if only 1 group in parent */
199 0 : if (parent->groups == parent->groups->next)
200 0 : pflags &= ~SD_DEGENERATE_GROUPS_MASK;
201 :
202 0 : if (~cflags & pflags)
203 0 : return 0;
204 :
205 : return 1;
206 : }
207 :
208 : #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
209 : DEFINE_STATIC_KEY_FALSE(sched_energy_present);
210 : unsigned int sysctl_sched_energy_aware = 1;
211 : DEFINE_MUTEX(sched_energy_mutex);
212 : bool sched_energy_update;
213 :
214 : void rebuild_sched_domains_energy(void)
215 : {
216 : mutex_lock(&sched_energy_mutex);
217 : sched_energy_update = true;
218 : rebuild_sched_domains();
219 : sched_energy_update = false;
220 : mutex_unlock(&sched_energy_mutex);
221 : }
222 :
223 : #ifdef CONFIG_PROC_SYSCTL
224 : int sched_energy_aware_handler(struct ctl_table *table, int write,
225 : void *buffer, size_t *lenp, loff_t *ppos)
226 : {
227 : int ret, state;
228 :
229 : if (write && !capable(CAP_SYS_ADMIN))
230 : return -EPERM;
231 :
232 : ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
233 : if (!ret && write) {
234 : state = static_branch_unlikely(&sched_energy_present);
235 : if (state != sysctl_sched_energy_aware)
236 : rebuild_sched_domains_energy();
237 : }
238 :
239 : return ret;
240 : }
241 : #endif
242 :
243 : static void free_pd(struct perf_domain *pd)
244 : {
245 : struct perf_domain *tmp;
246 :
247 : while (pd) {
248 : tmp = pd->next;
249 : kfree(pd);
250 : pd = tmp;
251 : }
252 : }
253 :
254 : static struct perf_domain *find_pd(struct perf_domain *pd, int cpu)
255 : {
256 : while (pd) {
257 : if (cpumask_test_cpu(cpu, perf_domain_span(pd)))
258 : return pd;
259 : pd = pd->next;
260 : }
261 :
262 : return NULL;
263 : }
264 :
265 : static struct perf_domain *pd_init(int cpu)
266 : {
267 : struct em_perf_domain *obj = em_cpu_get(cpu);
268 : struct perf_domain *pd;
269 :
270 : if (!obj) {
271 : if (sched_debug())
272 : pr_info("%s: no EM found for CPU%d\n", __func__, cpu);
273 : return NULL;
274 : }
275 :
276 : pd = kzalloc(sizeof(*pd), GFP_KERNEL);
277 : if (!pd)
278 : return NULL;
279 : pd->em_pd = obj;
280 :
281 : return pd;
282 : }
283 :
284 : static void perf_domain_debug(const struct cpumask *cpu_map,
285 : struct perf_domain *pd)
286 : {
287 : if (!sched_debug() || !pd)
288 : return;
289 :
290 : printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map));
291 :
292 : while (pd) {
293 : printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_pstate=%d }",
294 : cpumask_first(perf_domain_span(pd)),
295 : cpumask_pr_args(perf_domain_span(pd)),
296 : em_pd_nr_perf_states(pd->em_pd));
297 : pd = pd->next;
298 : }
299 :
300 : printk(KERN_CONT "\n");
301 : }
302 :
303 : static void destroy_perf_domain_rcu(struct rcu_head *rp)
304 : {
305 : struct perf_domain *pd;
306 :
307 : pd = container_of(rp, struct perf_domain, rcu);
308 : free_pd(pd);
309 : }
310 :
311 : static void sched_energy_set(bool has_eas)
312 : {
313 : if (!has_eas && static_branch_unlikely(&sched_energy_present)) {
314 : if (sched_debug())
315 : pr_info("%s: stopping EAS\n", __func__);
316 : static_branch_disable_cpuslocked(&sched_energy_present);
317 : } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) {
318 : if (sched_debug())
319 : pr_info("%s: starting EAS\n", __func__);
320 : static_branch_enable_cpuslocked(&sched_energy_present);
321 : }
322 : }
323 :
324 : /*
325 : * EAS can be used on a root domain if it meets all the following conditions:
326 : * 1. an Energy Model (EM) is available;
327 : * 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
328 : * 3. no SMT is detected.
329 : * 4. the EM complexity is low enough to keep scheduling overheads low;
330 : * 5. schedutil is driving the frequency of all CPUs of the rd;
331 : * 6. frequency invariance support is present;
332 : *
333 : * The complexity of the Energy Model is defined as:
334 : *
335 : * C = nr_pd * (nr_cpus + nr_ps)
336 : *
337 : * with parameters defined as:
338 : * - nr_pd: the number of performance domains
339 : * - nr_cpus: the number of CPUs
340 : * - nr_ps: the sum of the number of performance states of all performance
341 : * domains (for example, on a system with 2 performance domains,
342 : * with 10 performance states each, nr_ps = 2 * 10 = 20).
343 : *
344 : * It is generally not a good idea to use such a model in the wake-up path on
345 : * very complex platforms because of the associated scheduling overheads. The
346 : * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs
347 : * with per-CPU DVFS and less than 8 performance states each, for example.
348 : */
349 : #define EM_MAX_COMPLEXITY 2048
350 :
351 : extern struct cpufreq_governor schedutil_gov;
352 : static bool build_perf_domains(const struct cpumask *cpu_map)
353 : {
354 : int i, nr_pd = 0, nr_ps = 0, nr_cpus = cpumask_weight(cpu_map);
355 : struct perf_domain *pd = NULL, *tmp;
356 : int cpu = cpumask_first(cpu_map);
357 : struct root_domain *rd = cpu_rq(cpu)->rd;
358 : struct cpufreq_policy *policy;
359 : struct cpufreq_governor *gov;
360 :
361 : if (!sysctl_sched_energy_aware)
362 : goto free;
363 :
364 : /* EAS is enabled for asymmetric CPU capacity topologies. */
365 : if (!per_cpu(sd_asym_cpucapacity, cpu)) {
366 : if (sched_debug()) {
367 : pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n",
368 : cpumask_pr_args(cpu_map));
369 : }
370 : goto free;
371 : }
372 :
373 : /* EAS definitely does *not* handle SMT */
374 : if (sched_smt_active()) {
375 : pr_warn("rd %*pbl: Disabling EAS, SMT is not supported\n",
376 : cpumask_pr_args(cpu_map));
377 : goto free;
378 : }
379 :
380 : if (!arch_scale_freq_invariant()) {
381 : if (sched_debug()) {
382 : pr_warn("rd %*pbl: Disabling EAS: frequency-invariant load tracking not yet supported",
383 : cpumask_pr_args(cpu_map));
384 : }
385 : goto free;
386 : }
387 :
388 : for_each_cpu(i, cpu_map) {
389 : /* Skip already covered CPUs. */
390 : if (find_pd(pd, i))
391 : continue;
392 :
393 : /* Do not attempt EAS if schedutil is not being used. */
394 : policy = cpufreq_cpu_get(i);
395 : if (!policy)
396 : goto free;
397 : gov = policy->governor;
398 : cpufreq_cpu_put(policy);
399 : if (gov != &schedutil_gov) {
400 : if (rd->pd)
401 : pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n",
402 : cpumask_pr_args(cpu_map));
403 : goto free;
404 : }
405 :
406 : /* Create the new pd and add it to the local list. */
407 : tmp = pd_init(i);
408 : if (!tmp)
409 : goto free;
410 : tmp->next = pd;
411 : pd = tmp;
412 :
413 : /*
414 : * Count performance domains and performance states for the
415 : * complexity check.
416 : */
417 : nr_pd++;
418 : nr_ps += em_pd_nr_perf_states(pd->em_pd);
419 : }
420 :
421 : /* Bail out if the Energy Model complexity is too high. */
422 : if (nr_pd * (nr_ps + nr_cpus) > EM_MAX_COMPLEXITY) {
423 : WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n",
424 : cpumask_pr_args(cpu_map));
425 : goto free;
426 : }
427 :
428 : perf_domain_debug(cpu_map, pd);
429 :
430 : /* Attach the new list of performance domains to the root domain. */
431 : tmp = rd->pd;
432 : rcu_assign_pointer(rd->pd, pd);
433 : if (tmp)
434 : call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
435 :
436 : return !!pd;
437 :
438 : free:
439 : free_pd(pd);
440 : tmp = rd->pd;
441 : rcu_assign_pointer(rd->pd, NULL);
442 : if (tmp)
443 : call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
444 :
445 : return false;
446 : }
447 : #else
448 0 : static void free_pd(struct perf_domain *pd) { }
449 : #endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/
450 :
451 0 : static void free_rootdomain(struct rcu_head *rcu)
452 : {
453 0 : struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
454 :
455 0 : cpupri_cleanup(&rd->cpupri);
456 0 : cpudl_cleanup(&rd->cpudl);
457 0 : free_cpumask_var(rd->dlo_mask);
458 0 : free_cpumask_var(rd->rto_mask);
459 0 : free_cpumask_var(rd->online);
460 0 : free_cpumask_var(rd->span);
461 0 : free_pd(rd->pd);
462 0 : kfree(rd);
463 0 : }
464 :
465 8 : void rq_attach_root(struct rq *rq, struct root_domain *rd)
466 : {
467 8 : struct root_domain *old_rd = NULL;
468 8 : unsigned long flags;
469 :
470 8 : raw_spin_lock_irqsave(&rq->lock, flags);
471 :
472 8 : if (rq->rd) {
473 4 : old_rd = rq->rd;
474 :
475 4 : if (cpumask_test_cpu(rq->cpu, old_rd->online))
476 4 : set_rq_offline(rq);
477 :
478 4 : cpumask_clear_cpu(rq->cpu, old_rd->span);
479 :
480 : /*
481 : * If we dont want to free the old_rd yet then
482 : * set old_rd to NULL to skip the freeing later
483 : * in this function:
484 : */
485 8 : if (!atomic_dec_and_test(&old_rd->refcount))
486 4 : old_rd = NULL;
487 : }
488 :
489 8 : atomic_inc(&rd->refcount);
490 8 : rq->rd = rd;
491 :
492 8 : cpumask_set_cpu(rq->cpu, rd->span);
493 8 : if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
494 5 : set_rq_online(rq);
495 :
496 8 : raw_spin_unlock_irqrestore(&rq->lock, flags);
497 :
498 8 : if (old_rd)
499 0 : call_rcu(&old_rd->rcu, free_rootdomain);
500 8 : }
501 :
502 0 : void sched_get_rd(struct root_domain *rd)
503 : {
504 0 : atomic_inc(&rd->refcount);
505 0 : }
506 :
507 0 : void sched_put_rd(struct root_domain *rd)
508 : {
509 0 : if (!atomic_dec_and_test(&rd->refcount))
510 : return;
511 :
512 0 : call_rcu(&rd->rcu, free_rootdomain);
513 : }
514 :
515 2 : static int init_rootdomain(struct root_domain *rd)
516 : {
517 2 : if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
518 : goto out;
519 2 : if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
520 : goto free_span;
521 2 : if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
522 : goto free_online;
523 2 : if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
524 : goto free_dlo_mask;
525 :
526 : #ifdef HAVE_RT_PUSH_IPI
527 2 : rd->rto_cpu = -1;
528 2 : raw_spin_lock_init(&rd->rto_lock);
529 2 : init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
530 : #endif
531 :
532 2 : rd->visit_gen = 0;
533 2 : init_dl_bw(&rd->dl_bw);
534 2 : if (cpudl_init(&rd->cpudl) != 0)
535 0 : goto free_rto_mask;
536 :
537 2 : if (cpupri_init(&rd->cpupri) != 0)
538 0 : goto free_cpudl;
539 : return 0;
540 :
541 0 : free_cpudl:
542 0 : cpudl_cleanup(&rd->cpudl);
543 0 : free_rto_mask:
544 0 : free_cpumask_var(rd->rto_mask);
545 0 : free_dlo_mask:
546 0 : free_cpumask_var(rd->dlo_mask);
547 0 : free_online:
548 0 : free_cpumask_var(rd->online);
549 0 : free_span:
550 0 : free_cpumask_var(rd->span);
551 0 : out:
552 0 : return -ENOMEM;
553 : }
554 :
555 : /*
556 : * By default the system creates a single root-domain with all CPUs as
557 : * members (mimicking the global state we have today).
558 : */
559 : struct root_domain def_root_domain;
560 :
561 1 : void init_defrootdomain(void)
562 : {
563 1 : init_rootdomain(&def_root_domain);
564 :
565 1 : atomic_set(&def_root_domain.refcount, 1);
566 1 : }
567 :
568 1 : static struct root_domain *alloc_rootdomain(void)
569 : {
570 1 : struct root_domain *rd;
571 :
572 1 : rd = kzalloc(sizeof(*rd), GFP_KERNEL);
573 1 : if (!rd)
574 : return NULL;
575 :
576 1 : if (init_rootdomain(rd) != 0) {
577 0 : kfree(rd);
578 0 : return NULL;
579 : }
580 :
581 : return rd;
582 : }
583 :
584 8 : static void free_sched_groups(struct sched_group *sg, int free_sgc)
585 : {
586 8 : struct sched_group *tmp, *first;
587 :
588 8 : if (!sg)
589 : return;
590 :
591 8 : first = sg;
592 8 : do {
593 8 : tmp = sg->next;
594 :
595 16 : if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
596 8 : kfree(sg->sgc);
597 :
598 16 : if (atomic_dec_and_test(&sg->ref))
599 8 : kfree(sg);
600 8 : sg = tmp;
601 8 : } while (sg != first);
602 : }
603 :
604 8 : static void destroy_sched_domain(struct sched_domain *sd)
605 : {
606 : /*
607 : * A normal sched domain may have multiple group references, an
608 : * overlapping domain, having private groups, only one. Iterate,
609 : * dropping group/capacity references, freeing where none remain.
610 : */
611 8 : free_sched_groups(sd->groups, 1);
612 :
613 16 : if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
614 8 : kfree(sd->shared);
615 8 : kfree(sd);
616 8 : }
617 :
618 0 : static void destroy_sched_domains_rcu(struct rcu_head *rcu)
619 : {
620 0 : struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
621 :
622 0 : while (sd) {
623 0 : struct sched_domain *parent = sd->parent;
624 0 : destroy_sched_domain(sd);
625 0 : sd = parent;
626 : }
627 0 : }
628 :
629 4 : static void destroy_sched_domains(struct sched_domain *sd)
630 : {
631 4 : if (sd)
632 0 : call_rcu(&sd->rcu, destroy_sched_domains_rcu);
633 : }
634 :
635 : /*
636 : * Keep a special pointer to the highest sched_domain that has
637 : * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
638 : * allows us to avoid some pointer chasing select_idle_sibling().
639 : *
640 : * Also keep a unique ID per domain (we use the first CPU number in
641 : * the cpumask of the domain), this allows us to quickly tell if
642 : * two CPUs are in the same cache domain, see cpus_share_cache().
643 : */
644 : DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
645 : DEFINE_PER_CPU(int, sd_llc_size);
646 : DEFINE_PER_CPU(int, sd_llc_id);
647 : DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
648 : DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
649 : DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
650 : DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
651 : DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
652 :
653 4 : static void update_top_cache_domain(int cpu)
654 : {
655 4 : struct sched_domain_shared *sds = NULL;
656 4 : struct sched_domain *sd;
657 4 : int id = cpu;
658 4 : int size = 1;
659 :
660 4 : sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
661 4 : if (sd) {
662 0 : id = cpumask_first(sched_domain_span(sd));
663 0 : size = cpumask_weight(sched_domain_span(sd));
664 0 : sds = sd->shared;
665 : }
666 :
667 4 : rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
668 4 : per_cpu(sd_llc_size, cpu) = size;
669 4 : per_cpu(sd_llc_id, cpu) = id;
670 4 : rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
671 :
672 4 : sd = lowest_flag_domain(cpu, SD_NUMA);
673 4 : rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
674 :
675 4 : sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
676 4 : rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd);
677 :
678 4 : sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY);
679 4 : rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd);
680 4 : }
681 :
682 : /*
683 : * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
684 : * hold the hotplug lock.
685 : */
686 : static void
687 4 : cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
688 : {
689 4 : struct rq *rq = cpu_rq(cpu);
690 4 : struct sched_domain *tmp;
691 4 : int numa_distance = 0;
692 :
693 : /* Remove the sched domains which do not contribute to scheduling. */
694 16 : for (tmp = sd; tmp; ) {
695 12 : struct sched_domain *parent = tmp->parent;
696 12 : if (!parent)
697 : break;
698 :
699 8 : if (sd_parent_degenerate(tmp, parent)) {
700 4 : tmp->parent = parent->parent;
701 4 : if (parent->parent)
702 4 : parent->parent->child = tmp;
703 : /*
704 : * Transfer SD_PREFER_SIBLING down in case of a
705 : * degenerate parent; the spans match for this
706 : * so the property transfers.
707 : */
708 4 : if (parent->flags & SD_PREFER_SIBLING)
709 4 : tmp->flags |= SD_PREFER_SIBLING;
710 4 : destroy_sched_domain(parent);
711 : } else
712 : tmp = tmp->parent;
713 : }
714 :
715 4 : if (sd && sd_degenerate(sd)) {
716 4 : tmp = sd;
717 4 : sd = sd->parent;
718 4 : destroy_sched_domain(tmp);
719 4 : if (sd)
720 4 : sd->child = NULL;
721 : }
722 :
723 8 : for (tmp = sd; tmp; tmp = tmp->parent)
724 4 : numa_distance += !!(tmp->flags & SD_NUMA);
725 :
726 : /*
727 : * FIXME: Diameter >=3 is misrepresented.
728 : *
729 : * Smallest diameter=3 topology is:
730 : *
731 : * node 0 1 2 3
732 : * 0: 10 20 30 40
733 : * 1: 20 10 20 30
734 : * 2: 30 20 10 20
735 : * 3: 40 30 20 10
736 : *
737 : * 0 --- 1 --- 2 --- 3
738 : *
739 : * NUMA-3 0-3 N/A N/A 0-3
740 : * groups: {0-2},{1-3} {1-3},{0-2}
741 : *
742 : * NUMA-2 0-2 0-3 0-3 1-3
743 : * groups: {0-1},{1-3} {0-2},{2-3} {1-3},{0-1} {2-3},{0-2}
744 : *
745 : * NUMA-1 0-1 0-2 1-3 2-3
746 : * groups: {0},{1} {1},{2},{0} {2},{3},{1} {3},{2}
747 : *
748 : * NUMA-0 0 1 2 3
749 : *
750 : * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the
751 : * group span isn't a subset of the domain span.
752 : */
753 4 : WARN_ONCE(numa_distance > 2, "Shortest NUMA path spans too many nodes\n");
754 :
755 4 : sched_domain_debug(sd, cpu);
756 :
757 4 : rq_attach_root(rq, rd);
758 4 : tmp = rq->sd;
759 4 : rcu_assign_pointer(rq->sd, sd);
760 4 : dirty_sched_domain_sysctl(cpu);
761 4 : destroy_sched_domains(tmp);
762 :
763 4 : update_top_cache_domain(cpu);
764 4 : }
765 :
766 : struct s_data {
767 : struct sched_domain * __percpu *sd;
768 : struct root_domain *rd;
769 : };
770 :
771 : enum s_alloc {
772 : sa_rootdomain,
773 : sa_sd,
774 : sa_sd_storage,
775 : sa_none,
776 : };
777 :
778 : /*
779 : * Return the canonical balance CPU for this group, this is the first CPU
780 : * of this group that's also in the balance mask.
781 : *
782 : * The balance mask are all those CPUs that could actually end up at this
783 : * group. See build_balance_mask().
784 : *
785 : * Also see should_we_balance().
786 : */
787 1721 : int group_balance_cpu(struct sched_group *sg)
788 : {
789 1709 : return cpumask_first(group_balance_mask(sg));
790 : }
791 :
792 :
793 : /*
794 : * NUMA topology (first read the regular topology blurb below)
795 : *
796 : * Given a node-distance table, for example:
797 : *
798 : * node 0 1 2 3
799 : * 0: 10 20 30 20
800 : * 1: 20 10 20 30
801 : * 2: 30 20 10 20
802 : * 3: 20 30 20 10
803 : *
804 : * which represents a 4 node ring topology like:
805 : *
806 : * 0 ----- 1
807 : * | |
808 : * | |
809 : * | |
810 : * 3 ----- 2
811 : *
812 : * We want to construct domains and groups to represent this. The way we go
813 : * about doing this is to build the domains on 'hops'. For each NUMA level we
814 : * construct the mask of all nodes reachable in @level hops.
815 : *
816 : * For the above NUMA topology that gives 3 levels:
817 : *
818 : * NUMA-2 0-3 0-3 0-3 0-3
819 : * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2}
820 : *
821 : * NUMA-1 0-1,3 0-2 1-3 0,2-3
822 : * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3}
823 : *
824 : * NUMA-0 0 1 2 3
825 : *
826 : *
827 : * As can be seen; things don't nicely line up as with the regular topology.
828 : * When we iterate a domain in child domain chunks some nodes can be
829 : * represented multiple times -- hence the "overlap" naming for this part of
830 : * the topology.
831 : *
832 : * In order to minimize this overlap, we only build enough groups to cover the
833 : * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3.
834 : *
835 : * Because:
836 : *
837 : * - the first group of each domain is its child domain; this
838 : * gets us the first 0-1,3
839 : * - the only uncovered node is 2, who's child domain is 1-3.
840 : *
841 : * However, because of the overlap, computing a unique CPU for each group is
842 : * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both
843 : * groups include the CPUs of Node-0, while those CPUs would not in fact ever
844 : * end up at those groups (they would end up in group: 0-1,3).
845 : *
846 : * To correct this we have to introduce the group balance mask. This mask
847 : * will contain those CPUs in the group that can reach this group given the
848 : * (child) domain tree.
849 : *
850 : * With this we can once again compute balance_cpu and sched_group_capacity
851 : * relations.
852 : *
853 : * XXX include words on how balance_cpu is unique and therefore can be
854 : * used for sched_group_capacity links.
855 : *
856 : *
857 : * Another 'interesting' topology is:
858 : *
859 : * node 0 1 2 3
860 : * 0: 10 20 20 30
861 : * 1: 20 10 20 20
862 : * 2: 20 20 10 20
863 : * 3: 30 20 20 10
864 : *
865 : * Which looks a little like:
866 : *
867 : * 0 ----- 1
868 : * | / |
869 : * | / |
870 : * | / |
871 : * 2 ----- 3
872 : *
873 : * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3
874 : * are not.
875 : *
876 : * This leads to a few particularly weird cases where the sched_domain's are
877 : * not of the same number for each CPU. Consider:
878 : *
879 : * NUMA-2 0-3 0-3
880 : * groups: {0-2},{1-3} {1-3},{0-2}
881 : *
882 : * NUMA-1 0-2 0-3 0-3 1-3
883 : *
884 : * NUMA-0 0 1 2 3
885 : *
886 : */
887 :
888 :
889 : /*
890 : * Build the balance mask; it contains only those CPUs that can arrive at this
891 : * group and should be considered to continue balancing.
892 : *
893 : * We do this during the group creation pass, therefore the group information
894 : * isn't complete yet, however since each group represents a (child) domain we
895 : * can fully construct this using the sched_domain bits (which are already
896 : * complete).
897 : */
898 : static void
899 0 : build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask)
900 : {
901 0 : const struct cpumask *sg_span = sched_group_span(sg);
902 0 : struct sd_data *sdd = sd->private;
903 0 : struct sched_domain *sibling;
904 0 : int i;
905 :
906 0 : cpumask_clear(mask);
907 :
908 0 : for_each_cpu(i, sg_span) {
909 0 : sibling = *per_cpu_ptr(sdd->sd, i);
910 :
911 : /*
912 : * Can happen in the asymmetric case, where these siblings are
913 : * unused. The mask will not be empty because those CPUs that
914 : * do have the top domain _should_ span the domain.
915 : */
916 0 : if (!sibling->child)
917 0 : continue;
918 :
919 : /* If we would not end up here, we can't continue from here */
920 0 : if (!cpumask_equal(sg_span, sched_domain_span(sibling->child)))
921 0 : continue;
922 :
923 0 : cpumask_set_cpu(i, mask);
924 : }
925 :
926 : /* We must not have empty masks here */
927 0 : WARN_ON_ONCE(cpumask_empty(mask));
928 0 : }
929 :
930 : /*
931 : * XXX: This creates per-node group entries; since the load-balancer will
932 : * immediately access remote memory to construct this group's load-balance
933 : * statistics having the groups node local is of dubious benefit.
934 : */
935 : static struct sched_group *
936 0 : build_group_from_child_sched_domain(struct sched_domain *sd, int cpu)
937 : {
938 0 : struct sched_group *sg;
939 0 : struct cpumask *sg_span;
940 :
941 0 : sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
942 : GFP_KERNEL, cpu_to_node(cpu));
943 :
944 0 : if (!sg)
945 : return NULL;
946 :
947 0 : sg_span = sched_group_span(sg);
948 0 : if (sd->child)
949 0 : cpumask_copy(sg_span, sched_domain_span(sd->child));
950 : else
951 0 : cpumask_copy(sg_span, sched_domain_span(sd));
952 :
953 0 : atomic_inc(&sg->ref);
954 0 : return sg;
955 : }
956 :
957 0 : static void init_overlap_sched_group(struct sched_domain *sd,
958 : struct sched_group *sg)
959 : {
960 0 : struct cpumask *mask = sched_domains_tmpmask2;
961 0 : struct sd_data *sdd = sd->private;
962 0 : struct cpumask *sg_span;
963 0 : int cpu;
964 :
965 0 : build_balance_mask(sd, sg, mask);
966 0 : cpu = cpumask_first_and(sched_group_span(sg), mask);
967 :
968 0 : sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
969 0 : if (atomic_inc_return(&sg->sgc->ref) == 1)
970 0 : cpumask_copy(group_balance_mask(sg), mask);
971 : else
972 0 : WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask));
973 :
974 : /*
975 : * Initialize sgc->capacity such that even if we mess up the
976 : * domains and no possible iteration will get us here, we won't
977 : * die on a /0 trap.
978 : */
979 0 : sg_span = sched_group_span(sg);
980 0 : sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
981 0 : sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
982 0 : sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
983 0 : }
984 :
985 : static int
986 0 : build_overlap_sched_groups(struct sched_domain *sd, int cpu)
987 : {
988 0 : struct sched_group *first = NULL, *last = NULL, *sg;
989 0 : const struct cpumask *span = sched_domain_span(sd);
990 0 : struct cpumask *covered = sched_domains_tmpmask;
991 0 : struct sd_data *sdd = sd->private;
992 0 : struct sched_domain *sibling;
993 0 : int i;
994 :
995 0 : cpumask_clear(covered);
996 :
997 0 : for_each_cpu_wrap(i, span, cpu) {
998 0 : struct cpumask *sg_span;
999 :
1000 0 : if (cpumask_test_cpu(i, covered))
1001 0 : continue;
1002 :
1003 0 : sibling = *per_cpu_ptr(sdd->sd, i);
1004 :
1005 : /*
1006 : * Asymmetric node setups can result in situations where the
1007 : * domain tree is of unequal depth, make sure to skip domains
1008 : * that already cover the entire range.
1009 : *
1010 : * In that case build_sched_domains() will have terminated the
1011 : * iteration early and our sibling sd spans will be empty.
1012 : * Domains should always include the CPU they're built on, so
1013 : * check that.
1014 : */
1015 0 : if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
1016 0 : continue;
1017 :
1018 0 : sg = build_group_from_child_sched_domain(sibling, cpu);
1019 0 : if (!sg)
1020 0 : goto fail;
1021 :
1022 0 : sg_span = sched_group_span(sg);
1023 0 : cpumask_or(covered, covered, sg_span);
1024 :
1025 0 : init_overlap_sched_group(sd, sg);
1026 :
1027 0 : if (!first)
1028 0 : first = sg;
1029 0 : if (last)
1030 0 : last->next = sg;
1031 0 : last = sg;
1032 0 : last->next = first;
1033 : }
1034 0 : sd->groups = first;
1035 :
1036 0 : return 0;
1037 :
1038 0 : fail:
1039 0 : free_sched_groups(first, 0);
1040 :
1041 0 : return -ENOMEM;
1042 : }
1043 :
1044 :
1045 : /*
1046 : * Package topology (also see the load-balance blurb in fair.c)
1047 : *
1048 : * The scheduler builds a tree structure to represent a number of important
1049 : * topology features. By default (default_topology[]) these include:
1050 : *
1051 : * - Simultaneous multithreading (SMT)
1052 : * - Multi-Core Cache (MC)
1053 : * - Package (DIE)
1054 : *
1055 : * Where the last one more or less denotes everything up to a NUMA node.
1056 : *
1057 : * The tree consists of 3 primary data structures:
1058 : *
1059 : * sched_domain -> sched_group -> sched_group_capacity
1060 : * ^ ^ ^ ^
1061 : * `-' `-'
1062 : *
1063 : * The sched_domains are per-CPU and have a two way link (parent & child) and
1064 : * denote the ever growing mask of CPUs belonging to that level of topology.
1065 : *
1066 : * Each sched_domain has a circular (double) linked list of sched_group's, each
1067 : * denoting the domains of the level below (or individual CPUs in case of the
1068 : * first domain level). The sched_group linked by a sched_domain includes the
1069 : * CPU of that sched_domain [*].
1070 : *
1071 : * Take for instance a 2 threaded, 2 core, 2 cache cluster part:
1072 : *
1073 : * CPU 0 1 2 3 4 5 6 7
1074 : *
1075 : * DIE [ ]
1076 : * MC [ ] [ ]
1077 : * SMT [ ] [ ] [ ] [ ]
1078 : *
1079 : * - or -
1080 : *
1081 : * DIE 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7
1082 : * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7
1083 : * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7
1084 : *
1085 : * CPU 0 1 2 3 4 5 6 7
1086 : *
1087 : * One way to think about it is: sched_domain moves you up and down among these
1088 : * topology levels, while sched_group moves you sideways through it, at child
1089 : * domain granularity.
1090 : *
1091 : * sched_group_capacity ensures each unique sched_group has shared storage.
1092 : *
1093 : * There are two related construction problems, both require a CPU that
1094 : * uniquely identify each group (for a given domain):
1095 : *
1096 : * - The first is the balance_cpu (see should_we_balance() and the
1097 : * load-balance blub in fair.c); for each group we only want 1 CPU to
1098 : * continue balancing at a higher domain.
1099 : *
1100 : * - The second is the sched_group_capacity; we want all identical groups
1101 : * to share a single sched_group_capacity.
1102 : *
1103 : * Since these topologies are exclusive by construction. That is, its
1104 : * impossible for an SMT thread to belong to multiple cores, and cores to
1105 : * be part of multiple caches. There is a very clear and unique location
1106 : * for each CPU in the hierarchy.
1107 : *
1108 : * Therefore computing a unique CPU for each group is trivial (the iteration
1109 : * mask is redundant and set all 1s; all CPUs in a group will end up at _that_
1110 : * group), we can simply pick the first CPU in each group.
1111 : *
1112 : *
1113 : * [*] in other words, the first group of each domain is its child domain.
1114 : */
1115 :
1116 24 : static struct sched_group *get_group(int cpu, struct sd_data *sdd)
1117 : {
1118 24 : struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
1119 24 : struct sched_domain *child = sd->child;
1120 24 : struct sched_group *sg;
1121 24 : bool already_visited;
1122 :
1123 24 : if (child)
1124 20 : cpu = cpumask_first(sched_domain_span(child));
1125 :
1126 24 : sg = *per_cpu_ptr(sdd->sg, cpu);
1127 24 : sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
1128 :
1129 : /* Increase refcounts for claim_allocations: */
1130 24 : already_visited = atomic_inc_return(&sg->ref) > 1;
1131 : /* sgc visits should follow a similar trend as sg */
1132 48 : WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1));
1133 :
1134 : /* If we have already visited that group, it's already initialized. */
1135 24 : if (already_visited)
1136 : return sg;
1137 :
1138 12 : if (child) {
1139 8 : cpumask_copy(sched_group_span(sg), sched_domain_span(child));
1140 8 : cpumask_copy(group_balance_mask(sg), sched_group_span(sg));
1141 : } else {
1142 4 : cpumask_set_cpu(cpu, sched_group_span(sg));
1143 4 : cpumask_set_cpu(cpu, group_balance_mask(sg));
1144 : }
1145 :
1146 12 : sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
1147 12 : sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
1148 12 : sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
1149 :
1150 12 : return sg;
1151 : }
1152 :
1153 : /*
1154 : * build_sched_groups will build a circular linked list of the groups
1155 : * covered by the given span, will set each group's ->cpumask correctly,
1156 : * and will initialize their ->sgc.
1157 : *
1158 : * Assumes the sched_domain tree is fully constructed
1159 : */
1160 : static int
1161 12 : build_sched_groups(struct sched_domain *sd, int cpu)
1162 : {
1163 12 : struct sched_group *first = NULL, *last = NULL;
1164 12 : struct sd_data *sdd = sd->private;
1165 12 : const struct cpumask *span = sched_domain_span(sd);
1166 12 : struct cpumask *covered;
1167 12 : int i;
1168 :
1169 36 : lockdep_assert_held(&sched_domains_mutex);
1170 12 : covered = sched_domains_tmpmask;
1171 :
1172 12 : cpumask_clear(covered);
1173 :
1174 36 : for_each_cpu_wrap(i, span, cpu) {
1175 24 : struct sched_group *sg;
1176 :
1177 24 : if (cpumask_test_cpu(i, covered))
1178 0 : continue;
1179 :
1180 24 : sg = get_group(i, sdd);
1181 :
1182 24 : cpumask_or(covered, covered, sched_group_span(sg));
1183 :
1184 24 : if (!first)
1185 12 : first = sg;
1186 24 : if (last)
1187 12 : last->next = sg;
1188 : last = sg;
1189 : }
1190 12 : last->next = first;
1191 12 : sd->groups = first;
1192 :
1193 12 : return 0;
1194 : }
1195 :
1196 : /*
1197 : * Initialize sched groups cpu_capacity.
1198 : *
1199 : * cpu_capacity indicates the capacity of sched group, which is used while
1200 : * distributing the load between different sched groups in a sched domain.
1201 : * Typically cpu_capacity for all the groups in a sched domain will be same
1202 : * unless there are asymmetries in the topology. If there are asymmetries,
1203 : * group having more cpu_capacity will pickup more load compared to the
1204 : * group having less cpu_capacity.
1205 : */
1206 12 : static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
1207 : {
1208 12 : struct sched_group *sg = sd->groups;
1209 :
1210 12 : WARN_ON(!sg);
1211 :
1212 24 : do {
1213 24 : int cpu, max_cpu = -1;
1214 :
1215 24 : sg->group_weight = cpumask_weight(sched_group_span(sg));
1216 :
1217 24 : if (!(sd->flags & SD_ASYM_PACKING))
1218 24 : goto next;
1219 :
1220 0 : for_each_cpu(cpu, sched_group_span(sg)) {
1221 0 : if (max_cpu < 0)
1222 : max_cpu = cpu;
1223 0 : else if (sched_asym_prefer(cpu, max_cpu))
1224 0 : max_cpu = cpu;
1225 : }
1226 0 : sg->asym_prefer_cpu = max_cpu;
1227 :
1228 24 : next:
1229 24 : sg = sg->next;
1230 24 : } while (sg != sd->groups);
1231 :
1232 12 : if (cpu != group_balance_cpu(sg))
1233 : return;
1234 :
1235 12 : update_group_capacity(sd, cpu);
1236 : }
1237 :
1238 : /*
1239 : * Initializers for schedule domains
1240 : * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
1241 : */
1242 :
1243 : static int default_relax_domain_level = -1;
1244 : int sched_domain_level_max;
1245 :
1246 0 : static int __init setup_relax_domain_level(char *str)
1247 : {
1248 0 : if (kstrtoint(str, 0, &default_relax_domain_level))
1249 0 : pr_warn("Unable to set relax_domain_level\n");
1250 :
1251 0 : return 1;
1252 : }
1253 : __setup("relax_domain_level=", setup_relax_domain_level);
1254 :
1255 12 : static void set_domain_attribute(struct sched_domain *sd,
1256 : struct sched_domain_attr *attr)
1257 : {
1258 12 : int request;
1259 :
1260 12 : if (!attr || attr->relax_domain_level < 0) {
1261 12 : if (default_relax_domain_level < 0)
1262 : return;
1263 : request = default_relax_domain_level;
1264 : } else
1265 : request = attr->relax_domain_level;
1266 :
1267 0 : if (sd->level > request) {
1268 : /* Turn off idle balance on this domain: */
1269 0 : sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
1270 : }
1271 : }
1272 :
1273 : static void __sdt_free(const struct cpumask *cpu_map);
1274 : static int __sdt_alloc(const struct cpumask *cpu_map);
1275 :
1276 1 : static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
1277 : const struct cpumask *cpu_map)
1278 : {
1279 1 : switch (what) {
1280 1 : case sa_rootdomain:
1281 1 : if (!atomic_read(&d->rd->refcount))
1282 0 : free_rootdomain(&d->rd->rcu);
1283 1 : fallthrough;
1284 : case sa_sd:
1285 1 : free_percpu(d->sd);
1286 1 : fallthrough;
1287 1 : case sa_sd_storage:
1288 1 : __sdt_free(cpu_map);
1289 : fallthrough;
1290 : case sa_none:
1291 : break;
1292 : }
1293 1 : }
1294 :
1295 : static enum s_alloc
1296 1 : __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map)
1297 : {
1298 1 : memset(d, 0, sizeof(*d));
1299 :
1300 1 : if (__sdt_alloc(cpu_map))
1301 : return sa_sd_storage;
1302 1 : d->sd = alloc_percpu(struct sched_domain *);
1303 1 : if (!d->sd)
1304 : return sa_sd_storage;
1305 1 : d->rd = alloc_rootdomain();
1306 1 : if (!d->rd)
1307 0 : return sa_sd;
1308 :
1309 : return sa_rootdomain;
1310 : }
1311 :
1312 : /*
1313 : * NULL the sd_data elements we've used to build the sched_domain and
1314 : * sched_group structure so that the subsequent __free_domain_allocs()
1315 : * will not free the data we're using.
1316 : */
1317 12 : static void claim_allocations(int cpu, struct sched_domain *sd)
1318 : {
1319 12 : struct sd_data *sdd = sd->private;
1320 :
1321 12 : WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
1322 12 : *per_cpu_ptr(sdd->sd, cpu) = NULL;
1323 :
1324 12 : if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
1325 8 : *per_cpu_ptr(sdd->sds, cpu) = NULL;
1326 :
1327 12 : if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
1328 12 : *per_cpu_ptr(sdd->sg, cpu) = NULL;
1329 :
1330 12 : if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
1331 12 : *per_cpu_ptr(sdd->sgc, cpu) = NULL;
1332 12 : }
1333 :
1334 : #ifdef CONFIG_NUMA
1335 : enum numa_topology_type sched_numa_topology_type;
1336 :
1337 : static int sched_domains_numa_levels;
1338 : static int sched_domains_curr_level;
1339 :
1340 : int sched_max_numa_distance;
1341 : static int *sched_domains_numa_distance;
1342 : static struct cpumask ***sched_domains_numa_masks;
1343 : int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE;
1344 : #endif
1345 :
1346 : /*
1347 : * SD_flags allowed in topology descriptions.
1348 : *
1349 : * These flags are purely descriptive of the topology and do not prescribe
1350 : * behaviour. Behaviour is artificial and mapped in the below sd_init()
1351 : * function:
1352 : *
1353 : * SD_SHARE_CPUCAPACITY - describes SMT topologies
1354 : * SD_SHARE_PKG_RESOURCES - describes shared caches
1355 : * SD_NUMA - describes NUMA topologies
1356 : *
1357 : * Odd one out, which beside describing the topology has a quirk also
1358 : * prescribes the desired behaviour that goes along with it:
1359 : *
1360 : * SD_ASYM_PACKING - describes SMT quirks
1361 : */
1362 : #define TOPOLOGY_SD_FLAGS \
1363 : (SD_SHARE_CPUCAPACITY | \
1364 : SD_SHARE_PKG_RESOURCES | \
1365 : SD_NUMA | \
1366 : SD_ASYM_PACKING)
1367 :
1368 : static struct sched_domain *
1369 12 : sd_init(struct sched_domain_topology_level *tl,
1370 : const struct cpumask *cpu_map,
1371 : struct sched_domain *child, int dflags, int cpu)
1372 : {
1373 12 : struct sd_data *sdd = &tl->data;
1374 12 : struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
1375 12 : int sd_id, sd_weight, sd_flags = 0;
1376 :
1377 : #ifdef CONFIG_NUMA
1378 : /*
1379 : * Ugly hack to pass state to sd_numa_mask()...
1380 : */
1381 12 : sched_domains_curr_level = tl->numa_level;
1382 : #endif
1383 :
1384 12 : sd_weight = cpumask_weight(tl->mask(cpu));
1385 :
1386 12 : if (tl->sd_flags)
1387 8 : sd_flags = (*tl->sd_flags)();
1388 12 : if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
1389 : "wrong sd_flags in topology description\n"))
1390 0 : sd_flags &= TOPOLOGY_SD_FLAGS;
1391 :
1392 : /* Apply detected topology flags */
1393 12 : sd_flags |= dflags;
1394 :
1395 12 : *sd = (struct sched_domain){
1396 : .min_interval = sd_weight,
1397 12 : .max_interval = 2*sd_weight,
1398 : .busy_factor = 16,
1399 : .imbalance_pct = 117,
1400 :
1401 : .cache_nice_tries = 0,
1402 :
1403 : .flags = 1*SD_BALANCE_NEWIDLE
1404 : | 1*SD_BALANCE_EXEC
1405 : | 1*SD_BALANCE_FORK
1406 : | 0*SD_BALANCE_WAKE
1407 : | 1*SD_WAKE_AFFINE
1408 : | 0*SD_SHARE_CPUCAPACITY
1409 : | 0*SD_SHARE_PKG_RESOURCES
1410 : | 0*SD_SERIALIZE
1411 : | 1*SD_PREFER_SIBLING
1412 : | 0*SD_NUMA
1413 12 : | sd_flags
1414 : ,
1415 :
1416 : .last_balance = jiffies,
1417 : .balance_interval = sd_weight,
1418 : .max_newidle_lb_cost = 0,
1419 : .next_decay_max_lb_cost = jiffies,
1420 : .child = child,
1421 : #ifdef CONFIG_SCHED_DEBUG
1422 : .name = tl->name,
1423 : #endif
1424 : };
1425 :
1426 12 : cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
1427 12 : sd_id = cpumask_first(sched_domain_span(sd));
1428 :
1429 : /*
1430 : * Convert topological properties into behaviour.
1431 : */
1432 :
1433 : /* Don't attempt to spread across CPUs of different capacities. */
1434 12 : if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child)
1435 0 : sd->child->flags &= ~SD_PREFER_SIBLING;
1436 :
1437 12 : if (sd->flags & SD_SHARE_CPUCAPACITY) {
1438 4 : sd->imbalance_pct = 110;
1439 :
1440 8 : } else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
1441 4 : sd->imbalance_pct = 117;
1442 4 : sd->cache_nice_tries = 1;
1443 :
1444 : #ifdef CONFIG_NUMA
1445 4 : } else if (sd->flags & SD_NUMA) {
1446 0 : sd->cache_nice_tries = 2;
1447 :
1448 0 : sd->flags &= ~SD_PREFER_SIBLING;
1449 0 : sd->flags |= SD_SERIALIZE;
1450 0 : if (sched_domains_numa_distance[tl->numa_level] > node_reclaim_distance) {
1451 0 : sd->flags &= ~(SD_BALANCE_EXEC |
1452 : SD_BALANCE_FORK |
1453 : SD_WAKE_AFFINE);
1454 : }
1455 :
1456 : #endif
1457 : } else {
1458 4 : sd->cache_nice_tries = 1;
1459 : }
1460 :
1461 : /*
1462 : * For all levels sharing cache; connect a sched_domain_shared
1463 : * instance.
1464 : */
1465 12 : if (sd->flags & SD_SHARE_PKG_RESOURCES) {
1466 8 : sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
1467 8 : atomic_inc(&sd->shared->ref);
1468 8 : atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
1469 : }
1470 :
1471 12 : sd->private = sdd;
1472 :
1473 12 : return sd;
1474 : }
1475 :
1476 : /*
1477 : * Topology list, bottom-up.
1478 : */
1479 : static struct sched_domain_topology_level default_topology[] = {
1480 : #ifdef CONFIG_SCHED_SMT
1481 : { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
1482 : #endif
1483 : #ifdef CONFIG_SCHED_MC
1484 : { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
1485 : #endif
1486 : { cpu_cpu_mask, SD_INIT_NAME(DIE) },
1487 : { NULL, },
1488 : };
1489 :
1490 : static struct sched_domain_topology_level *sched_domain_topology =
1491 : default_topology;
1492 :
1493 : #define for_each_sd_topology(tl) \
1494 : for (tl = sched_domain_topology; tl->mask; tl++)
1495 :
1496 1 : void set_sched_topology(struct sched_domain_topology_level *tl)
1497 : {
1498 1 : if (WARN_ON_ONCE(sched_smp_initialized))
1499 : return;
1500 :
1501 1 : sched_domain_topology = tl;
1502 : }
1503 :
1504 : #ifdef CONFIG_NUMA
1505 :
1506 0 : static const struct cpumask *sd_numa_mask(int cpu)
1507 : {
1508 0 : return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
1509 : }
1510 :
1511 0 : static void sched_numa_warn(const char *str)
1512 : {
1513 0 : static int done = false;
1514 0 : int i,j;
1515 :
1516 0 : if (done)
1517 : return;
1518 :
1519 0 : done = true;
1520 :
1521 0 : printk(KERN_WARNING "ERROR: %s\n\n", str);
1522 :
1523 0 : for (i = 0; i < nr_node_ids; i++) {
1524 0 : printk(KERN_WARNING " ");
1525 0 : for (j = 0; j < nr_node_ids; j++)
1526 0 : printk(KERN_CONT "%02d ", node_distance(i,j));
1527 0 : printk(KERN_CONT "\n");
1528 : }
1529 0 : printk(KERN_WARNING "\n");
1530 : }
1531 :
1532 0 : bool find_numa_distance(int distance)
1533 : {
1534 0 : int i;
1535 :
1536 0 : if (distance == node_distance(0, 0))
1537 : return true;
1538 :
1539 0 : for (i = 0; i < sched_domains_numa_levels; i++) {
1540 0 : if (sched_domains_numa_distance[i] == distance)
1541 : return true;
1542 : }
1543 :
1544 : return false;
1545 : }
1546 :
1547 : /*
1548 : * A system can have three types of NUMA topology:
1549 : * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
1550 : * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
1551 : * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
1552 : *
1553 : * The difference between a glueless mesh topology and a backplane
1554 : * topology lies in whether communication between not directly
1555 : * connected nodes goes through intermediary nodes (where programs
1556 : * could run), or through backplane controllers. This affects
1557 : * placement of programs.
1558 : *
1559 : * The type of topology can be discerned with the following tests:
1560 : * - If the maximum distance between any nodes is 1 hop, the system
1561 : * is directly connected.
1562 : * - If for two nodes A and B, located N > 1 hops away from each other,
1563 : * there is an intermediary node C, which is < N hops away from both
1564 : * nodes A and B, the system is a glueless mesh.
1565 : */
1566 1 : static void init_numa_topology_type(void)
1567 : {
1568 1 : int a, b, c, n;
1569 :
1570 1 : n = sched_max_numa_distance;
1571 :
1572 1 : if (sched_domains_numa_levels <= 2) {
1573 1 : sched_numa_topology_type = NUMA_DIRECT;
1574 1 : return;
1575 : }
1576 :
1577 0 : for_each_online_node(a) {
1578 0 : for_each_online_node(b) {
1579 : /* Find two nodes furthest removed from each other. */
1580 0 : if (node_distance(a, b) < n)
1581 0 : continue;
1582 :
1583 : /* Is there an intermediary node between a and b? */
1584 0 : for_each_online_node(c) {
1585 0 : if (node_distance(a, c) < n &&
1586 0 : node_distance(b, c) < n) {
1587 0 : sched_numa_topology_type =
1588 : NUMA_GLUELESS_MESH;
1589 0 : return;
1590 : }
1591 : }
1592 :
1593 0 : sched_numa_topology_type = NUMA_BACKPLANE;
1594 0 : return;
1595 : }
1596 : }
1597 : }
1598 :
1599 :
1600 : #define NR_DISTANCE_VALUES (1 << DISTANCE_BITS)
1601 :
1602 1 : void sched_init_numa(void)
1603 : {
1604 1 : struct sched_domain_topology_level *tl;
1605 1 : unsigned long *distance_map;
1606 1 : int nr_levels = 0;
1607 1 : int i, j;
1608 :
1609 : /*
1610 : * O(nr_nodes^2) deduplicating selection sort -- in order to find the
1611 : * unique distances in the node_distance() table.
1612 : */
1613 1 : distance_map = bitmap_alloc(NR_DISTANCE_VALUES, GFP_KERNEL);
1614 1 : if (!distance_map)
1615 : return;
1616 :
1617 1 : bitmap_zero(distance_map, NR_DISTANCE_VALUES);
1618 2 : for (i = 0; i < nr_node_ids; i++) {
1619 2 : for (j = 0; j < nr_node_ids; j++) {
1620 1 : int distance = node_distance(i, j);
1621 :
1622 1 : if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) {
1623 0 : sched_numa_warn("Invalid distance value range");
1624 0 : return;
1625 : }
1626 :
1627 1 : bitmap_set(distance_map, distance, 1);
1628 : }
1629 : }
1630 : /*
1631 : * We can now figure out how many unique distance values there are and
1632 : * allocate memory accordingly.
1633 : */
1634 1 : nr_levels = bitmap_weight(distance_map, NR_DISTANCE_VALUES);
1635 :
1636 1 : sched_domains_numa_distance = kcalloc(nr_levels, sizeof(int), GFP_KERNEL);
1637 1 : if (!sched_domains_numa_distance) {
1638 0 : bitmap_free(distance_map);
1639 0 : return;
1640 : }
1641 :
1642 2 : for (i = 0, j = 0; i < nr_levels; i++, j++) {
1643 1 : j = find_next_bit(distance_map, NR_DISTANCE_VALUES, j);
1644 1 : sched_domains_numa_distance[i] = j;
1645 : }
1646 :
1647 1 : bitmap_free(distance_map);
1648 :
1649 : /*
1650 : * 'nr_levels' contains the number of unique distances
1651 : *
1652 : * The sched_domains_numa_distance[] array includes the actual distance
1653 : * numbers.
1654 : */
1655 :
1656 : /*
1657 : * Here, we should temporarily reset sched_domains_numa_levels to 0.
1658 : * If it fails to allocate memory for array sched_domains_numa_masks[][],
1659 : * the array will contain less then 'nr_levels' members. This could be
1660 : * dangerous when we use it to iterate array sched_domains_numa_masks[][]
1661 : * in other functions.
1662 : *
1663 : * We reset it to 'nr_levels' at the end of this function.
1664 : */
1665 1 : sched_domains_numa_levels = 0;
1666 :
1667 1 : sched_domains_numa_masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
1668 1 : if (!sched_domains_numa_masks)
1669 : return;
1670 :
1671 : /*
1672 : * Now for each level, construct a mask per node which contains all
1673 : * CPUs of nodes that are that many hops away from us.
1674 : */
1675 2 : for (i = 0; i < nr_levels; i++) {
1676 2 : sched_domains_numa_masks[i] =
1677 1 : kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
1678 1 : if (!sched_domains_numa_masks[i])
1679 : return;
1680 :
1681 2 : for (j = 0; j < nr_node_ids; j++) {
1682 1 : struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
1683 1 : int k;
1684 :
1685 1 : if (!mask)
1686 : return;
1687 :
1688 1 : sched_domains_numa_masks[i][j] = mask;
1689 :
1690 2 : for_each_node(k) {
1691 1 : if (sched_debug() && (node_distance(j, k) != node_distance(k, j)))
1692 : sched_numa_warn("Node-distance not symmetric");
1693 :
1694 1 : if (node_distance(j, k) > sched_domains_numa_distance[i])
1695 0 : continue;
1696 :
1697 1 : cpumask_or(mask, mask, cpumask_of_node(k));
1698 : }
1699 : }
1700 : }
1701 :
1702 : /* Compute default topology size */
1703 4 : for (i = 0; sched_domain_topology[i].mask; i++);
1704 :
1705 1 : tl = kzalloc((i + nr_levels + 1) *
1706 : sizeof(struct sched_domain_topology_level), GFP_KERNEL);
1707 1 : if (!tl)
1708 : return;
1709 :
1710 : /*
1711 : * Copy the default topology bits..
1712 : */
1713 4 : for (i = 0; sched_domain_topology[i].mask; i++)
1714 3 : tl[i] = sched_domain_topology[i];
1715 :
1716 : /*
1717 : * Add the NUMA identity distance, aka single NODE.
1718 : */
1719 1 : tl[i++] = (struct sched_domain_topology_level){
1720 : .mask = sd_numa_mask,
1721 : .numa_level = 0,
1722 : SD_INIT_NAME(NODE)
1723 : };
1724 :
1725 : /*
1726 : * .. and append 'j' levels of NUMA goodness.
1727 : */
1728 1 : for (j = 1; j < nr_levels; i++, j++) {
1729 0 : tl[i] = (struct sched_domain_topology_level){
1730 : .mask = sd_numa_mask,
1731 : .sd_flags = cpu_numa_flags,
1732 : .flags = SDTL_OVERLAP,
1733 : .numa_level = j,
1734 : SD_INIT_NAME(NUMA)
1735 : };
1736 : }
1737 :
1738 1 : sched_domain_topology = tl;
1739 :
1740 1 : sched_domains_numa_levels = nr_levels;
1741 1 : sched_max_numa_distance = sched_domains_numa_distance[nr_levels - 1];
1742 :
1743 1 : init_numa_topology_type();
1744 : }
1745 :
1746 0 : void sched_domains_numa_masks_set(unsigned int cpu)
1747 : {
1748 0 : int node = cpu_to_node(cpu);
1749 0 : int i, j;
1750 :
1751 0 : for (i = 0; i < sched_domains_numa_levels; i++) {
1752 0 : for (j = 0; j < nr_node_ids; j++) {
1753 0 : if (node_distance(j, node) <= sched_domains_numa_distance[i])
1754 0 : cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
1755 : }
1756 : }
1757 0 : }
1758 :
1759 0 : void sched_domains_numa_masks_clear(unsigned int cpu)
1760 : {
1761 0 : int i, j;
1762 :
1763 0 : for (i = 0; i < sched_domains_numa_levels; i++) {
1764 0 : for (j = 0; j < nr_node_ids; j++)
1765 0 : cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
1766 : }
1767 0 : }
1768 :
1769 : /*
1770 : * sched_numa_find_closest() - given the NUMA topology, find the cpu
1771 : * closest to @cpu from @cpumask.
1772 : * cpumask: cpumask to find a cpu from
1773 : * cpu: cpu to be close to
1774 : *
1775 : * returns: cpu, or nr_cpu_ids when nothing found.
1776 : */
1777 0 : int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
1778 : {
1779 0 : int i, j = cpu_to_node(cpu);
1780 :
1781 0 : for (i = 0; i < sched_domains_numa_levels; i++) {
1782 0 : cpu = cpumask_any_and(cpus, sched_domains_numa_masks[i][j]);
1783 0 : if (cpu < nr_cpu_ids)
1784 0 : return cpu;
1785 : }
1786 0 : return nr_cpu_ids;
1787 : }
1788 :
1789 : #endif /* CONFIG_NUMA */
1790 :
1791 1 : static int __sdt_alloc(const struct cpumask *cpu_map)
1792 : {
1793 1 : struct sched_domain_topology_level *tl;
1794 1 : int j;
1795 :
1796 5 : for_each_sd_topology(tl) {
1797 4 : struct sd_data *sdd = &tl->data;
1798 :
1799 4 : sdd->sd = alloc_percpu(struct sched_domain *);
1800 4 : if (!sdd->sd)
1801 : return -ENOMEM;
1802 :
1803 4 : sdd->sds = alloc_percpu(struct sched_domain_shared *);
1804 4 : if (!sdd->sds)
1805 : return -ENOMEM;
1806 :
1807 4 : sdd->sg = alloc_percpu(struct sched_group *);
1808 4 : if (!sdd->sg)
1809 : return -ENOMEM;
1810 :
1811 4 : sdd->sgc = alloc_percpu(struct sched_group_capacity *);
1812 4 : if (!sdd->sgc)
1813 : return -ENOMEM;
1814 :
1815 20 : for_each_cpu(j, cpu_map) {
1816 16 : struct sched_domain *sd;
1817 16 : struct sched_domain_shared *sds;
1818 16 : struct sched_group *sg;
1819 16 : struct sched_group_capacity *sgc;
1820 :
1821 16 : sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
1822 : GFP_KERNEL, cpu_to_node(j));
1823 16 : if (!sd)
1824 : return -ENOMEM;
1825 :
1826 16 : *per_cpu_ptr(sdd->sd, j) = sd;
1827 :
1828 16 : sds = kzalloc_node(sizeof(struct sched_domain_shared),
1829 : GFP_KERNEL, cpu_to_node(j));
1830 16 : if (!sds)
1831 : return -ENOMEM;
1832 :
1833 16 : *per_cpu_ptr(sdd->sds, j) = sds;
1834 :
1835 16 : sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
1836 : GFP_KERNEL, cpu_to_node(j));
1837 16 : if (!sg)
1838 : return -ENOMEM;
1839 :
1840 16 : sg->next = sg;
1841 :
1842 16 : *per_cpu_ptr(sdd->sg, j) = sg;
1843 :
1844 16 : sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
1845 : GFP_KERNEL, cpu_to_node(j));
1846 16 : if (!sgc)
1847 : return -ENOMEM;
1848 :
1849 : #ifdef CONFIG_SCHED_DEBUG
1850 : sgc->id = j;
1851 : #endif
1852 :
1853 16 : *per_cpu_ptr(sdd->sgc, j) = sgc;
1854 : }
1855 : }
1856 :
1857 : return 0;
1858 : }
1859 :
1860 1 : static void __sdt_free(const struct cpumask *cpu_map)
1861 : {
1862 1 : struct sched_domain_topology_level *tl;
1863 1 : int j;
1864 :
1865 5 : for_each_sd_topology(tl) {
1866 20 : struct sd_data *sdd = &tl->data;
1867 :
1868 20 : for_each_cpu(j, cpu_map) {
1869 16 : struct sched_domain *sd;
1870 :
1871 16 : if (sdd->sd) {
1872 16 : sd = *per_cpu_ptr(sdd->sd, j);
1873 16 : if (sd && (sd->flags & SD_OVERLAP))
1874 0 : free_sched_groups(sd->groups, 0);
1875 16 : kfree(*per_cpu_ptr(sdd->sd, j));
1876 : }
1877 :
1878 16 : if (sdd->sds)
1879 16 : kfree(*per_cpu_ptr(sdd->sds, j));
1880 16 : if (sdd->sg)
1881 16 : kfree(*per_cpu_ptr(sdd->sg, j));
1882 16 : if (sdd->sgc)
1883 16 : kfree(*per_cpu_ptr(sdd->sgc, j));
1884 : }
1885 4 : free_percpu(sdd->sd);
1886 4 : sdd->sd = NULL;
1887 4 : free_percpu(sdd->sds);
1888 4 : sdd->sds = NULL;
1889 4 : free_percpu(sdd->sg);
1890 4 : sdd->sg = NULL;
1891 4 : free_percpu(sdd->sgc);
1892 4 : sdd->sgc = NULL;
1893 : }
1894 1 : }
1895 :
1896 12 : static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
1897 : const struct cpumask *cpu_map, struct sched_domain_attr *attr,
1898 : struct sched_domain *child, int dflags, int cpu)
1899 : {
1900 12 : struct sched_domain *sd = sd_init(tl, cpu_map, child, dflags, cpu);
1901 :
1902 12 : if (child) {
1903 8 : sd->level = child->level + 1;
1904 8 : sched_domain_level_max = max(sched_domain_level_max, sd->level);
1905 8 : child->parent = sd;
1906 :
1907 8 : if (!cpumask_subset(sched_domain_span(child),
1908 8 : sched_domain_span(sd))) {
1909 0 : pr_err("BUG: arch topology borken\n");
1910 : #ifdef CONFIG_SCHED_DEBUG
1911 : pr_err(" the %s domain not a subset of the %s domain\n",
1912 : child->name, sd->name);
1913 : #endif
1914 : /* Fixup, ensure @sd has at least @child CPUs. */
1915 0 : cpumask_or(sched_domain_span(sd),
1916 0 : sched_domain_span(sd),
1917 0 : sched_domain_span(child));
1918 : }
1919 :
1920 : }
1921 12 : set_domain_attribute(sd, attr);
1922 :
1923 12 : return sd;
1924 : }
1925 :
1926 : /*
1927 : * Ensure topology masks are sane, i.e. there are no conflicts (overlaps) for
1928 : * any two given CPUs at this (non-NUMA) topology level.
1929 : */
1930 12 : static bool topology_span_sane(struct sched_domain_topology_level *tl,
1931 : const struct cpumask *cpu_map, int cpu)
1932 : {
1933 12 : int i;
1934 :
1935 : /* NUMA levels are allowed to overlap */
1936 12 : if (tl->flags & SDTL_OVERLAP)
1937 : return true;
1938 :
1939 : /*
1940 : * Non-NUMA levels cannot partially overlap - they must be either
1941 : * completely equal or completely disjoint. Otherwise we can end up
1942 : * breaking the sched_group lists - i.e. a later get_group() pass
1943 : * breaks the linking done for an earlier span.
1944 : */
1945 60 : for_each_cpu(i, cpu_map) {
1946 48 : if (i == cpu)
1947 12 : continue;
1948 : /*
1949 : * We should 'and' all those masks with 'cpu_map' to exactly
1950 : * match the topology we're about to build, but that can only
1951 : * remove CPUs, which only lessens our ability to detect
1952 : * overlaps
1953 : */
1954 60 : if (!cpumask_equal(tl->mask(cpu), tl->mask(i)) &&
1955 24 : cpumask_intersects(tl->mask(cpu), tl->mask(i)))
1956 : return false;
1957 : }
1958 :
1959 : return true;
1960 : }
1961 :
1962 : /*
1963 : * Find the sched_domain_topology_level where all CPU capacities are visible
1964 : * for all CPUs.
1965 : */
1966 : static struct sched_domain_topology_level
1967 1 : *asym_cpu_capacity_level(const struct cpumask *cpu_map)
1968 : {
1969 1 : int i, j, asym_level = 0;
1970 1 : bool asym = false;
1971 1 : struct sched_domain_topology_level *tl, *asym_tl = NULL;
1972 1 : unsigned long cap;
1973 :
1974 : /* Is there any asymmetry? */
1975 1 : cap = arch_scale_cpu_capacity(cpumask_first(cpu_map));
1976 :
1977 6 : for_each_cpu(i, cpu_map) {
1978 5 : if (arch_scale_cpu_capacity(i) != cap) {
1979 : asym = true;
1980 : break;
1981 : }
1982 : }
1983 :
1984 1 : if (!asym)
1985 1 : return NULL;
1986 :
1987 : /*
1988 : * Examine topology from all CPU's point of views to detect the lowest
1989 : * sched_domain_topology_level where a highest capacity CPU is visible
1990 : * to everyone.
1991 : */
1992 : for_each_cpu(i, cpu_map) {
1993 : unsigned long max_capacity = arch_scale_cpu_capacity(i);
1994 : int tl_id = 0;
1995 :
1996 : for_each_sd_topology(tl) {
1997 : if (tl_id < asym_level)
1998 : goto next_level;
1999 :
2000 : for_each_cpu_and(j, tl->mask(i), cpu_map) {
2001 : unsigned long capacity;
2002 :
2003 : capacity = arch_scale_cpu_capacity(j);
2004 :
2005 : if (capacity <= max_capacity)
2006 : continue;
2007 :
2008 : max_capacity = capacity;
2009 : asym_level = tl_id;
2010 : asym_tl = tl;
2011 : }
2012 : next_level:
2013 : tl_id++;
2014 : }
2015 : }
2016 :
2017 : return asym_tl;
2018 : }
2019 :
2020 :
2021 : /*
2022 : * Build sched domains for a given set of CPUs and attach the sched domains
2023 : * to the individual CPUs
2024 : */
2025 : static int
2026 1 : build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr)
2027 : {
2028 1 : enum s_alloc alloc_state = sa_none;
2029 1 : struct sched_domain *sd;
2030 1 : struct s_data d;
2031 1 : struct rq *rq = NULL;
2032 1 : int i, ret = -ENOMEM;
2033 1 : struct sched_domain_topology_level *tl_asym;
2034 1 : bool has_asym = false;
2035 :
2036 1 : if (WARN_ON(cpumask_empty(cpu_map)))
2037 0 : goto error;
2038 :
2039 1 : alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
2040 1 : if (alloc_state != sa_rootdomain)
2041 0 : goto error;
2042 :
2043 1 : tl_asym = asym_cpu_capacity_level(cpu_map);
2044 :
2045 : /* Set up domains for CPUs specified by the cpu_map: */
2046 6 : for_each_cpu(i, cpu_map) {
2047 4 : struct sched_domain_topology_level *tl;
2048 4 : int dflags = 0;
2049 :
2050 4 : sd = NULL;
2051 12 : for_each_sd_topology(tl) {
2052 12 : if (tl == tl_asym) {
2053 0 : dflags |= SD_ASYM_CPUCAPACITY;
2054 0 : has_asym = true;
2055 : }
2056 :
2057 12 : if (WARN_ON(!topology_span_sane(tl, cpu_map, i)))
2058 0 : goto error;
2059 :
2060 12 : sd = build_sched_domain(tl, cpu_map, attr, sd, dflags, i);
2061 :
2062 12 : if (tl == sched_domain_topology)
2063 4 : *per_cpu_ptr(d.sd, i) = sd;
2064 12 : if (tl->flags & SDTL_OVERLAP)
2065 0 : sd->flags |= SD_OVERLAP;
2066 12 : if (cpumask_equal(cpu_map, sched_domain_span(sd)))
2067 : break;
2068 : }
2069 : }
2070 :
2071 : /* Build the groups for the domains */
2072 5 : for_each_cpu(i, cpu_map) {
2073 16 : for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
2074 12 : sd->span_weight = cpumask_weight(sched_domain_span(sd));
2075 12 : if (sd->flags & SD_OVERLAP) {
2076 0 : if (build_overlap_sched_groups(sd, i))
2077 0 : goto error;
2078 : } else {
2079 12 : if (build_sched_groups(sd, i))
2080 0 : goto error;
2081 : }
2082 : }
2083 : }
2084 :
2085 : /* Calculate CPU capacity for physical packages and nodes */
2086 17 : for (i = nr_cpumask_bits-1; i >= 0; i--) {
2087 16 : if (!cpumask_test_cpu(i, cpu_map))
2088 12 : continue;
2089 :
2090 16 : for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
2091 12 : claim_allocations(i, sd);
2092 12 : init_sched_groups_capacity(i, sd);
2093 : }
2094 : }
2095 :
2096 : /* Attach the domains */
2097 1 : rcu_read_lock();
2098 5 : for_each_cpu(i, cpu_map) {
2099 4 : rq = cpu_rq(i);
2100 4 : sd = *per_cpu_ptr(d.sd, i);
2101 :
2102 : /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
2103 4 : if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
2104 1 : WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
2105 :
2106 4 : cpu_attach_domain(sd, d.rd, i);
2107 : }
2108 1 : rcu_read_unlock();
2109 :
2110 1 : if (has_asym)
2111 0 : static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
2112 :
2113 : if (rq && sched_debug_enabled) {
2114 : pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
2115 : cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
2116 : }
2117 :
2118 : ret = 0;
2119 1 : error:
2120 1 : __free_domain_allocs(&d, alloc_state, cpu_map);
2121 :
2122 1 : return ret;
2123 : }
2124 :
2125 : /* Current sched domains: */
2126 : static cpumask_var_t *doms_cur;
2127 :
2128 : /* Number of sched domains in 'doms_cur': */
2129 : static int ndoms_cur;
2130 :
2131 : /* Attribues of custom domains in 'doms_cur' */
2132 : static struct sched_domain_attr *dattr_cur;
2133 :
2134 : /*
2135 : * Special case: If a kmalloc() of a doms_cur partition (array of
2136 : * cpumask) fails, then fallback to a single sched domain,
2137 : * as determined by the single cpumask fallback_doms.
2138 : */
2139 : static cpumask_var_t fallback_doms;
2140 :
2141 : /*
2142 : * arch_update_cpu_topology lets virtualized architectures update the
2143 : * CPU core maps. It is supposed to return 1 if the topology changed
2144 : * or 0 if it stayed the same.
2145 : */
2146 0 : int __weak arch_update_cpu_topology(void)
2147 : {
2148 0 : return 0;
2149 : }
2150 :
2151 1 : cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
2152 : {
2153 1 : int i;
2154 1 : cpumask_var_t *doms;
2155 :
2156 1 : doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL);
2157 1 : if (!doms)
2158 : return NULL;
2159 1 : for (i = 0; i < ndoms; i++) {
2160 : if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
2161 : free_sched_domains(doms, i);
2162 : return NULL;
2163 : }
2164 : }
2165 : return doms;
2166 : }
2167 :
2168 0 : void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
2169 : {
2170 0 : unsigned int i;
2171 0 : for (i = 0; i < ndoms; i++)
2172 : free_cpumask_var(doms[i]);
2173 0 : kfree(doms);
2174 0 : }
2175 :
2176 : /*
2177 : * Set up scheduler domains and groups. For now this just excludes isolated
2178 : * CPUs, but could be used to exclude other special cases in the future.
2179 : */
2180 1 : int sched_init_domains(const struct cpumask *cpu_map)
2181 : {
2182 1 : int err;
2183 :
2184 1 : zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL);
2185 1 : zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL);
2186 1 : zalloc_cpumask_var(&fallback_doms, GFP_KERNEL);
2187 :
2188 1 : arch_update_cpu_topology();
2189 1 : ndoms_cur = 1;
2190 1 : doms_cur = alloc_sched_domains(ndoms_cur);
2191 1 : if (!doms_cur)
2192 0 : doms_cur = &fallback_doms;
2193 1 : cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN));
2194 1 : err = build_sched_domains(doms_cur[0], NULL);
2195 1 : register_sched_domain_sysctl();
2196 :
2197 1 : return err;
2198 : }
2199 :
2200 : /*
2201 : * Detach sched domains from a group of CPUs specified in cpu_map
2202 : * These CPUs will now be attached to the NULL domain
2203 : */
2204 0 : static void detach_destroy_domains(const struct cpumask *cpu_map)
2205 : {
2206 0 : unsigned int cpu = cpumask_any(cpu_map);
2207 0 : int i;
2208 :
2209 0 : if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu)))
2210 0 : static_branch_dec_cpuslocked(&sched_asym_cpucapacity);
2211 :
2212 0 : rcu_read_lock();
2213 0 : for_each_cpu(i, cpu_map)
2214 0 : cpu_attach_domain(NULL, &def_root_domain, i);
2215 0 : rcu_read_unlock();
2216 0 : }
2217 :
2218 : /* handle null as "default" */
2219 0 : static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
2220 : struct sched_domain_attr *new, int idx_new)
2221 : {
2222 0 : struct sched_domain_attr tmp;
2223 :
2224 : /* Fast path: */
2225 0 : if (!new && !cur)
2226 : return 1;
2227 :
2228 0 : tmp = SD_ATTR_INIT;
2229 :
2230 0 : return !memcmp(cur ? (cur + idx_cur) : &tmp,
2231 0 : new ? (new + idx_new) : &tmp,
2232 : sizeof(struct sched_domain_attr));
2233 : }
2234 :
2235 : /*
2236 : * Partition sched domains as specified by the 'ndoms_new'
2237 : * cpumasks in the array doms_new[] of cpumasks. This compares
2238 : * doms_new[] to the current sched domain partitioning, doms_cur[].
2239 : * It destroys each deleted domain and builds each new domain.
2240 : *
2241 : * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
2242 : * The masks don't intersect (don't overlap.) We should setup one
2243 : * sched domain for each mask. CPUs not in any of the cpumasks will
2244 : * not be load balanced. If the same cpumask appears both in the
2245 : * current 'doms_cur' domains and in the new 'doms_new', we can leave
2246 : * it as it is.
2247 : *
2248 : * The passed in 'doms_new' should be allocated using
2249 : * alloc_sched_domains. This routine takes ownership of it and will
2250 : * free_sched_domains it when done with it. If the caller failed the
2251 : * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
2252 : * and partition_sched_domains() will fallback to the single partition
2253 : * 'fallback_doms', it also forces the domains to be rebuilt.
2254 : *
2255 : * If doms_new == NULL it will be replaced with cpu_online_mask.
2256 : * ndoms_new == 0 is a special case for destroying existing domains,
2257 : * and it will not create the default domain.
2258 : *
2259 : * Call with hotplug lock and sched_domains_mutex held
2260 : */
2261 0 : void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
2262 : struct sched_domain_attr *dattr_new)
2263 : {
2264 0 : bool __maybe_unused has_eas = false;
2265 0 : int i, j, n;
2266 0 : int new_topology;
2267 :
2268 0 : lockdep_assert_held(&sched_domains_mutex);
2269 :
2270 : /* Always unregister in case we don't destroy any domains: */
2271 0 : unregister_sched_domain_sysctl();
2272 :
2273 : /* Let the architecture update CPU core mappings: */
2274 0 : new_topology = arch_update_cpu_topology();
2275 :
2276 0 : if (!doms_new) {
2277 0 : WARN_ON_ONCE(dattr_new);
2278 0 : n = 0;
2279 0 : doms_new = alloc_sched_domains(1);
2280 0 : if (doms_new) {
2281 0 : n = 1;
2282 0 : cpumask_and(doms_new[0], cpu_active_mask,
2283 : housekeeping_cpumask(HK_FLAG_DOMAIN));
2284 : }
2285 : } else {
2286 : n = ndoms_new;
2287 : }
2288 :
2289 : /* Destroy deleted domains: */
2290 0 : for (i = 0; i < ndoms_cur; i++) {
2291 0 : for (j = 0; j < n && !new_topology; j++) {
2292 0 : if (cpumask_equal(doms_cur[i], doms_new[j]) &&
2293 0 : dattrs_equal(dattr_cur, i, dattr_new, j)) {
2294 0 : struct root_domain *rd;
2295 :
2296 : /*
2297 : * This domain won't be destroyed and as such
2298 : * its dl_bw->total_bw needs to be cleared. It
2299 : * will be recomputed in function
2300 : * update_tasks_root_domain().
2301 : */
2302 0 : rd = cpu_rq(cpumask_any(doms_cur[i]))->rd;
2303 0 : dl_clear_root_domain(rd);
2304 0 : goto match1;
2305 : }
2306 : }
2307 : /* No match - a current sched domain not in new doms_new[] */
2308 0 : detach_destroy_domains(doms_cur[i]);
2309 0 : match1:
2310 0 : ;
2311 : }
2312 :
2313 0 : n = ndoms_cur;
2314 0 : if (!doms_new) {
2315 0 : n = 0;
2316 0 : doms_new = &fallback_doms;
2317 0 : cpumask_and(doms_new[0], cpu_active_mask,
2318 : housekeeping_cpumask(HK_FLAG_DOMAIN));
2319 : }
2320 :
2321 : /* Build new domains: */
2322 0 : for (i = 0; i < ndoms_new; i++) {
2323 0 : for (j = 0; j < n && !new_topology; j++) {
2324 0 : if (cpumask_equal(doms_new[i], doms_cur[j]) &&
2325 0 : dattrs_equal(dattr_new, i, dattr_cur, j))
2326 0 : goto match2;
2327 : }
2328 : /* No match - add a new doms_new */
2329 0 : build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
2330 0 : match2:
2331 0 : ;
2332 : }
2333 :
2334 : #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
2335 : /* Build perf. domains: */
2336 : for (i = 0; i < ndoms_new; i++) {
2337 : for (j = 0; j < n && !sched_energy_update; j++) {
2338 : if (cpumask_equal(doms_new[i], doms_cur[j]) &&
2339 : cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) {
2340 : has_eas = true;
2341 : goto match3;
2342 : }
2343 : }
2344 : /* No match - add perf. domains for a new rd */
2345 : has_eas |= build_perf_domains(doms_new[i]);
2346 : match3:
2347 : ;
2348 : }
2349 : sched_energy_set(has_eas);
2350 : #endif
2351 :
2352 : /* Remember the new sched domains: */
2353 0 : if (doms_cur != &fallback_doms)
2354 0 : free_sched_domains(doms_cur, ndoms_cur);
2355 :
2356 0 : kfree(dattr_cur);
2357 0 : doms_cur = doms_new;
2358 0 : dattr_cur = dattr_new;
2359 0 : ndoms_cur = ndoms_new;
2360 :
2361 0 : register_sched_domain_sysctl();
2362 0 : }
2363 :
2364 : /*
2365 : * Call with hotplug lock held
2366 : */
2367 0 : void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
2368 : struct sched_domain_attr *dattr_new)
2369 : {
2370 0 : mutex_lock(&sched_domains_mutex);
2371 0 : partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
2372 0 : mutex_unlock(&sched_domains_mutex);
2373 0 : }
|
