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_verbose = true; 18 19 return 0; 20 } 21 early_param("sched_verbose", sched_debug_setup); 22 23 static inline bool sched_debug(void) 24 { 25 return sched_debug_verbose; 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_verbose) 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_verbose 0 156 # define sched_domain_debug(sd, cpu) do { } while (0) 157 static inline bool sched_debug(void) 158 { 159 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 static int sd_degenerate(struct sched_domain *sd) 171 { 172 if (cpumask_weight(sched_domain_span(sd)) == 1) 173 return 1; 174 175 /* Following flags need at least 2 groups */ 176 if ((sd->flags & SD_DEGENERATE_GROUPS_MASK) && 177 (sd->groups != sd->groups->next)) 178 return 0; 179 180 /* Following flags don't use groups */ 181 if (sd->flags & (SD_WAKE_AFFINE)) 182 return 0; 183 184 return 1; 185 } 186 187 static int 188 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 189 { 190 unsigned long cflags = sd->flags, pflags = parent->flags; 191 192 if (sd_degenerate(parent)) 193 return 1; 194 195 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 if (parent->groups == parent->groups->next) 200 pflags &= ~SD_DEGENERATE_GROUPS_MASK; 201 202 if (~cflags & pflags) 203 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 static void free_pd(struct perf_domain *pd) { } 449 #endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/ 450 451 static void free_rootdomain(struct rcu_head *rcu) 452 { 453 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 454 455 cpupri_cleanup(&rd->cpupri); 456 cpudl_cleanup(&rd->cpudl); 457 free_cpumask_var(rd->dlo_mask); 458 free_cpumask_var(rd->rto_mask); 459 free_cpumask_var(rd->online); 460 free_cpumask_var(rd->span); 461 free_pd(rd->pd); 462 kfree(rd); 463 } 464 465 void rq_attach_root(struct rq *rq, struct root_domain *rd) 466 { 467 struct root_domain *old_rd = NULL; 468 unsigned long flags; 469 470 raw_spin_lock_irqsave(&rq->lock, flags); 471 472 if (rq->rd) { 473 old_rd = rq->rd; 474 475 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 476 set_rq_offline(rq); 477 478 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 if (!atomic_dec_and_test(&old_rd->refcount)) 486 old_rd = NULL; 487 } 488 489 atomic_inc(&rd->refcount); 490 rq->rd = rd; 491 492 cpumask_set_cpu(rq->cpu, rd->span); 493 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 494 set_rq_online(rq); 495 496 raw_spin_unlock_irqrestore(&rq->lock, flags); 497 498 if (old_rd) 499 call_rcu(&old_rd->rcu, free_rootdomain); 500 } 501 502 void sched_get_rd(struct root_domain *rd) 503 { 504 atomic_inc(&rd->refcount); 505 } 506 507 void sched_put_rd(struct root_domain *rd) 508 { 509 if (!atomic_dec_and_test(&rd->refcount)) 510 return; 511 512 call_rcu(&rd->rcu, free_rootdomain); 513 } 514 515 static int init_rootdomain(struct root_domain *rd) 516 { 517 if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) 518 goto out; 519 if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) 520 goto free_span; 521 if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 522 goto free_online; 523 if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 524 goto free_dlo_mask; 525 526 #ifdef HAVE_RT_PUSH_IPI 527 rd->rto_cpu = -1; 528 raw_spin_lock_init(&rd->rto_lock); 529 init_irq_work(&rd->rto_push_work, rto_push_irq_work_func); 530 #endif 531 532 rd->visit_gen = 0; 533 init_dl_bw(&rd->dl_bw); 534 if (cpudl_init(&rd->cpudl) != 0) 535 goto free_rto_mask; 536 537 if (cpupri_init(&rd->cpupri) != 0) 538 goto free_cpudl; 539 return 0; 540 541 free_cpudl: 542 cpudl_cleanup(&rd->cpudl); 543 free_rto_mask: 544 free_cpumask_var(rd->rto_mask); 545 free_dlo_mask: 546 free_cpumask_var(rd->dlo_mask); 547 free_online: 548 free_cpumask_var(rd->online); 549 free_span: 550 free_cpumask_var(rd->span); 551 out: 552 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 void init_defrootdomain(void) 562 { 563 init_rootdomain(&def_root_domain); 564 565 atomic_set(&def_root_domain.refcount, 1); 566 } 567 568 static struct root_domain *alloc_rootdomain(void) 569 { 570 struct root_domain *rd; 571 572 rd = kzalloc(sizeof(*rd), GFP_KERNEL); 573 if (!rd) 574 return NULL; 575 576 if (init_rootdomain(rd) != 0) { 577 kfree(rd); 578 return NULL; 579 } 580 581 return rd; 582 } 583 584 static void free_sched_groups(struct sched_group *sg, int free_sgc) 585 { 586 struct sched_group *tmp, *first; 587 588 if (!sg) 589 return; 590 591 first = sg; 592 do { 593 tmp = sg->next; 594 595 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) 596 kfree(sg->sgc); 597 598 if (atomic_dec_and_test(&sg->ref)) 599 kfree(sg); 600 sg = tmp; 601 } while (sg != first); 602 } 603 604 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 free_sched_groups(sd->groups, 1); 612 613 if (sd->shared && atomic_dec_and_test(&sd->shared->ref)) 614 kfree(sd->shared); 615 kfree(sd); 616 } 617 618 static void destroy_sched_domains_rcu(struct rcu_head *rcu) 619 { 620 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 621 622 while (sd) { 623 struct sched_domain *parent = sd->parent; 624 destroy_sched_domain(sd); 625 sd = parent; 626 } 627 } 628 629 static void destroy_sched_domains(struct sched_domain *sd) 630 { 631 if (sd) 632 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 static void update_top_cache_domain(int cpu) 654 { 655 struct sched_domain_shared *sds = NULL; 656 struct sched_domain *sd; 657 int id = cpu; 658 int size = 1; 659 660 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 661 if (sd) { 662 id = cpumask_first(sched_domain_span(sd)); 663 size = cpumask_weight(sched_domain_span(sd)); 664 sds = sd->shared; 665 } 666 667 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 668 per_cpu(sd_llc_size, cpu) = size; 669 per_cpu(sd_llc_id, cpu) = id; 670 rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds); 671 672 sd = lowest_flag_domain(cpu, SD_NUMA); 673 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 674 675 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 676 rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd); 677 678 sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY); 679 rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd); 680 } 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 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 688 { 689 struct rq *rq = cpu_rq(cpu); 690 struct sched_domain *tmp; 691 int numa_distance = 0; 692 693 /* Remove the sched domains which do not contribute to scheduling. */ 694 for (tmp = sd; tmp; ) { 695 struct sched_domain *parent = tmp->parent; 696 if (!parent) 697 break; 698 699 if (sd_parent_degenerate(tmp, parent)) { 700 tmp->parent = parent->parent; 701 if (parent->parent) 702 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 if (parent->flags & SD_PREFER_SIBLING) 709 tmp->flags |= SD_PREFER_SIBLING; 710 destroy_sched_domain(parent); 711 } else 712 tmp = tmp->parent; 713 } 714 715 if (sd && sd_degenerate(sd)) { 716 tmp = sd; 717 sd = sd->parent; 718 destroy_sched_domain(tmp); 719 if (sd) 720 sd->child = NULL; 721 } 722 723 for (tmp = sd; tmp; tmp = tmp->parent) 724 numa_distance += !!(tmp->flags & SD_NUMA); 725 726 sched_domain_debug(sd, cpu); 727 728 rq_attach_root(rq, rd); 729 tmp = rq->sd; 730 rcu_assign_pointer(rq->sd, sd); 731 dirty_sched_domain_sysctl(cpu); 732 destroy_sched_domains(tmp); 733 734 update_top_cache_domain(cpu); 735 } 736 737 struct s_data { 738 struct sched_domain * __percpu *sd; 739 struct root_domain *rd; 740 }; 741 742 enum s_alloc { 743 sa_rootdomain, 744 sa_sd, 745 sa_sd_storage, 746 sa_none, 747 }; 748 749 /* 750 * Return the canonical balance CPU for this group, this is the first CPU 751 * of this group that's also in the balance mask. 752 * 753 * The balance mask are all those CPUs that could actually end up at this 754 * group. See build_balance_mask(). 755 * 756 * Also see should_we_balance(). 757 */ 758 int group_balance_cpu(struct sched_group *sg) 759 { 760 return cpumask_first(group_balance_mask(sg)); 761 } 762 763 764 /* 765 * NUMA topology (first read the regular topology blurb below) 766 * 767 * Given a node-distance table, for example: 768 * 769 * node 0 1 2 3 770 * 0: 10 20 30 20 771 * 1: 20 10 20 30 772 * 2: 30 20 10 20 773 * 3: 20 30 20 10 774 * 775 * which represents a 4 node ring topology like: 776 * 777 * 0 ----- 1 778 * | | 779 * | | 780 * | | 781 * 3 ----- 2 782 * 783 * We want to construct domains and groups to represent this. The way we go 784 * about doing this is to build the domains on 'hops'. For each NUMA level we 785 * construct the mask of all nodes reachable in @level hops. 786 * 787 * For the above NUMA topology that gives 3 levels: 788 * 789 * NUMA-2 0-3 0-3 0-3 0-3 790 * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2} 791 * 792 * NUMA-1 0-1,3 0-2 1-3 0,2-3 793 * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3} 794 * 795 * NUMA-0 0 1 2 3 796 * 797 * 798 * As can be seen; things don't nicely line up as with the regular topology. 799 * When we iterate a domain in child domain chunks some nodes can be 800 * represented multiple times -- hence the "overlap" naming for this part of 801 * the topology. 802 * 803 * In order to minimize this overlap, we only build enough groups to cover the 804 * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3. 805 * 806 * Because: 807 * 808 * - the first group of each domain is its child domain; this 809 * gets us the first 0-1,3 810 * - the only uncovered node is 2, who's child domain is 1-3. 811 * 812 * However, because of the overlap, computing a unique CPU for each group is 813 * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both 814 * groups include the CPUs of Node-0, while those CPUs would not in fact ever 815 * end up at those groups (they would end up in group: 0-1,3). 816 * 817 * To correct this we have to introduce the group balance mask. This mask 818 * will contain those CPUs in the group that can reach this group given the 819 * (child) domain tree. 820 * 821 * With this we can once again compute balance_cpu and sched_group_capacity 822 * relations. 823 * 824 * XXX include words on how balance_cpu is unique and therefore can be 825 * used for sched_group_capacity links. 826 * 827 * 828 * Another 'interesting' topology is: 829 * 830 * node 0 1 2 3 831 * 0: 10 20 20 30 832 * 1: 20 10 20 20 833 * 2: 20 20 10 20 834 * 3: 30 20 20 10 835 * 836 * Which looks a little like: 837 * 838 * 0 ----- 1 839 * | / | 840 * | / | 841 * | / | 842 * 2 ----- 3 843 * 844 * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3 845 * are not. 846 * 847 * This leads to a few particularly weird cases where the sched_domain's are 848 * not of the same number for each CPU. Consider: 849 * 850 * NUMA-2 0-3 0-3 851 * groups: {0-2},{1-3} {1-3},{0-2} 852 * 853 * NUMA-1 0-2 0-3 0-3 1-3 854 * 855 * NUMA-0 0 1 2 3 856 * 857 */ 858 859 860 /* 861 * Build the balance mask; it contains only those CPUs that can arrive at this 862 * group and should be considered to continue balancing. 863 * 864 * We do this during the group creation pass, therefore the group information 865 * isn't complete yet, however since each group represents a (child) domain we 866 * can fully construct this using the sched_domain bits (which are already 867 * complete). 868 */ 869 static void 870 build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask) 871 { 872 const struct cpumask *sg_span = sched_group_span(sg); 873 struct sd_data *sdd = sd->private; 874 struct sched_domain *sibling; 875 int i; 876 877 cpumask_clear(mask); 878 879 for_each_cpu(i, sg_span) { 880 sibling = *per_cpu_ptr(sdd->sd, i); 881 882 /* 883 * Can happen in the asymmetric case, where these siblings are 884 * unused. The mask will not be empty because those CPUs that 885 * do have the top domain _should_ span the domain. 886 */ 887 if (!sibling->child) 888 continue; 889 890 /* If we would not end up here, we can't continue from here */ 891 if (!cpumask_equal(sg_span, sched_domain_span(sibling->child))) 892 continue; 893 894 cpumask_set_cpu(i, mask); 895 } 896 897 /* We must not have empty masks here */ 898 WARN_ON_ONCE(cpumask_empty(mask)); 899 } 900 901 /* 902 * XXX: This creates per-node group entries; since the load-balancer will 903 * immediately access remote memory to construct this group's load-balance 904 * statistics having the groups node local is of dubious benefit. 905 */ 906 static struct sched_group * 907 build_group_from_child_sched_domain(struct sched_domain *sd, int cpu) 908 { 909 struct sched_group *sg; 910 struct cpumask *sg_span; 911 912 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 913 GFP_KERNEL, cpu_to_node(cpu)); 914 915 if (!sg) 916 return NULL; 917 918 sg_span = sched_group_span(sg); 919 if (sd->child) 920 cpumask_copy(sg_span, sched_domain_span(sd->child)); 921 else 922 cpumask_copy(sg_span, sched_domain_span(sd)); 923 924 atomic_inc(&sg->ref); 925 return sg; 926 } 927 928 static void init_overlap_sched_group(struct sched_domain *sd, 929 struct sched_group *sg) 930 { 931 struct cpumask *mask = sched_domains_tmpmask2; 932 struct sd_data *sdd = sd->private; 933 struct cpumask *sg_span; 934 int cpu; 935 936 build_balance_mask(sd, sg, mask); 937 cpu = cpumask_first(mask); 938 939 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); 940 if (atomic_inc_return(&sg->sgc->ref) == 1) 941 cpumask_copy(group_balance_mask(sg), mask); 942 else 943 WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask)); 944 945 /* 946 * Initialize sgc->capacity such that even if we mess up the 947 * domains and no possible iteration will get us here, we won't 948 * die on a /0 trap. 949 */ 950 sg_span = sched_group_span(sg); 951 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); 952 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; 953 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; 954 } 955 956 static struct sched_domain * 957 find_descended_sibling(struct sched_domain *sd, struct sched_domain *sibling) 958 { 959 /* 960 * The proper descendant would be the one whose child won't span out 961 * of sd 962 */ 963 while (sibling->child && 964 !cpumask_subset(sched_domain_span(sibling->child), 965 sched_domain_span(sd))) 966 sibling = sibling->child; 967 968 /* 969 * As we are referencing sgc across different topology level, we need 970 * to go down to skip those sched_domains which don't contribute to 971 * scheduling because they will be degenerated in cpu_attach_domain 972 */ 973 while (sibling->child && 974 cpumask_equal(sched_domain_span(sibling->child), 975 sched_domain_span(sibling))) 976 sibling = sibling->child; 977 978 return sibling; 979 } 980 981 static int 982 build_overlap_sched_groups(struct sched_domain *sd, int cpu) 983 { 984 struct sched_group *first = NULL, *last = NULL, *sg; 985 const struct cpumask *span = sched_domain_span(sd); 986 struct cpumask *covered = sched_domains_tmpmask; 987 struct sd_data *sdd = sd->private; 988 struct sched_domain *sibling; 989 int i; 990 991 cpumask_clear(covered); 992 993 for_each_cpu_wrap(i, span, cpu) { 994 struct cpumask *sg_span; 995 996 if (cpumask_test_cpu(i, covered)) 997 continue; 998 999 sibling = *per_cpu_ptr(sdd->sd, i); 1000 1001 /* 1002 * Asymmetric node setups can result in situations where the 1003 * domain tree is of unequal depth, make sure to skip domains 1004 * that already cover the entire range. 1005 * 1006 * In that case build_sched_domains() will have terminated the 1007 * iteration early and our sibling sd spans will be empty. 1008 * Domains should always include the CPU they're built on, so 1009 * check that. 1010 */ 1011 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 1012 continue; 1013 1014 /* 1015 * Usually we build sched_group by sibling's child sched_domain 1016 * But for machines whose NUMA diameter are 3 or above, we move 1017 * to build sched_group by sibling's proper descendant's child 1018 * domain because sibling's child sched_domain will span out of 1019 * the sched_domain being built as below. 1020 * 1021 * Smallest diameter=3 topology is: 1022 * 1023 * node 0 1 2 3 1024 * 0: 10 20 30 40 1025 * 1: 20 10 20 30 1026 * 2: 30 20 10 20 1027 * 3: 40 30 20 10 1028 * 1029 * 0 --- 1 --- 2 --- 3 1030 * 1031 * NUMA-3 0-3 N/A N/A 0-3 1032 * groups: {0-2},{1-3} {1-3},{0-2} 1033 * 1034 * NUMA-2 0-2 0-3 0-3 1-3 1035 * groups: {0-1},{1-3} {0-2},{2-3} {1-3},{0-1} {2-3},{0-2} 1036 * 1037 * NUMA-1 0-1 0-2 1-3 2-3 1038 * groups: {0},{1} {1},{2},{0} {2},{3},{1} {3},{2} 1039 * 1040 * NUMA-0 0 1 2 3 1041 * 1042 * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the 1043 * group span isn't a subset of the domain span. 1044 */ 1045 if (sibling->child && 1046 !cpumask_subset(sched_domain_span(sibling->child), span)) 1047 sibling = find_descended_sibling(sd, sibling); 1048 1049 sg = build_group_from_child_sched_domain(sibling, cpu); 1050 if (!sg) 1051 goto fail; 1052 1053 sg_span = sched_group_span(sg); 1054 cpumask_or(covered, covered, sg_span); 1055 1056 init_overlap_sched_group(sibling, sg); 1057 1058 if (!first) 1059 first = sg; 1060 if (last) 1061 last->next = sg; 1062 last = sg; 1063 last->next = first; 1064 } 1065 sd->groups = first; 1066 1067 return 0; 1068 1069 fail: 1070 free_sched_groups(first, 0); 1071 1072 return -ENOMEM; 1073 } 1074 1075 1076 /* 1077 * Package topology (also see the load-balance blurb in fair.c) 1078 * 1079 * The scheduler builds a tree structure to represent a number of important 1080 * topology features. By default (default_topology[]) these include: 1081 * 1082 * - Simultaneous multithreading (SMT) 1083 * - Multi-Core Cache (MC) 1084 * - Package (DIE) 1085 * 1086 * Where the last one more or less denotes everything up to a NUMA node. 1087 * 1088 * The tree consists of 3 primary data structures: 1089 * 1090 * sched_domain -> sched_group -> sched_group_capacity 1091 * ^ ^ ^ ^ 1092 * `-' `-' 1093 * 1094 * The sched_domains are per-CPU and have a two way link (parent & child) and 1095 * denote the ever growing mask of CPUs belonging to that level of topology. 1096 * 1097 * Each sched_domain has a circular (double) linked list of sched_group's, each 1098 * denoting the domains of the level below (or individual CPUs in case of the 1099 * first domain level). The sched_group linked by a sched_domain includes the 1100 * CPU of that sched_domain [*]. 1101 * 1102 * Take for instance a 2 threaded, 2 core, 2 cache cluster part: 1103 * 1104 * CPU 0 1 2 3 4 5 6 7 1105 * 1106 * DIE [ ] 1107 * MC [ ] [ ] 1108 * SMT [ ] [ ] [ ] [ ] 1109 * 1110 * - or - 1111 * 1112 * DIE 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7 1113 * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7 1114 * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7 1115 * 1116 * CPU 0 1 2 3 4 5 6 7 1117 * 1118 * One way to think about it is: sched_domain moves you up and down among these 1119 * topology levels, while sched_group moves you sideways through it, at child 1120 * domain granularity. 1121 * 1122 * sched_group_capacity ensures each unique sched_group has shared storage. 1123 * 1124 * There are two related construction problems, both require a CPU that 1125 * uniquely identify each group (for a given domain): 1126 * 1127 * - The first is the balance_cpu (see should_we_balance() and the 1128 * load-balance blub in fair.c); for each group we only want 1 CPU to 1129 * continue balancing at a higher domain. 1130 * 1131 * - The second is the sched_group_capacity; we want all identical groups 1132 * to share a single sched_group_capacity. 1133 * 1134 * Since these topologies are exclusive by construction. That is, its 1135 * impossible for an SMT thread to belong to multiple cores, and cores to 1136 * be part of multiple caches. There is a very clear and unique location 1137 * for each CPU in the hierarchy. 1138 * 1139 * Therefore computing a unique CPU for each group is trivial (the iteration 1140 * mask is redundant and set all 1s; all CPUs in a group will end up at _that_ 1141 * group), we can simply pick the first CPU in each group. 1142 * 1143 * 1144 * [*] in other words, the first group of each domain is its child domain. 1145 */ 1146 1147 static struct sched_group *get_group(int cpu, struct sd_data *sdd) 1148 { 1149 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 1150 struct sched_domain *child = sd->child; 1151 struct sched_group *sg; 1152 bool already_visited; 1153 1154 if (child) 1155 cpu = cpumask_first(sched_domain_span(child)); 1156 1157 sg = *per_cpu_ptr(sdd->sg, cpu); 1158 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); 1159 1160 /* Increase refcounts for claim_allocations: */ 1161 already_visited = atomic_inc_return(&sg->ref) > 1; 1162 /* sgc visits should follow a similar trend as sg */ 1163 WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1)); 1164 1165 /* If we have already visited that group, it's already initialized. */ 1166 if (already_visited) 1167 return sg; 1168 1169 if (child) { 1170 cpumask_copy(sched_group_span(sg), sched_domain_span(child)); 1171 cpumask_copy(group_balance_mask(sg), sched_group_span(sg)); 1172 } else { 1173 cpumask_set_cpu(cpu, sched_group_span(sg)); 1174 cpumask_set_cpu(cpu, group_balance_mask(sg)); 1175 } 1176 1177 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg)); 1178 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; 1179 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; 1180 1181 return sg; 1182 } 1183 1184 /* 1185 * build_sched_groups will build a circular linked list of the groups 1186 * covered by the given span, will set each group's ->cpumask correctly, 1187 * and will initialize their ->sgc. 1188 * 1189 * Assumes the sched_domain tree is fully constructed 1190 */ 1191 static int 1192 build_sched_groups(struct sched_domain *sd, int cpu) 1193 { 1194 struct sched_group *first = NULL, *last = NULL; 1195 struct sd_data *sdd = sd->private; 1196 const struct cpumask *span = sched_domain_span(sd); 1197 struct cpumask *covered; 1198 int i; 1199 1200 lockdep_assert_held(&sched_domains_mutex); 1201 covered = sched_domains_tmpmask; 1202 1203 cpumask_clear(covered); 1204 1205 for_each_cpu_wrap(i, span, cpu) { 1206 struct sched_group *sg; 1207 1208 if (cpumask_test_cpu(i, covered)) 1209 continue; 1210 1211 sg = get_group(i, sdd); 1212 1213 cpumask_or(covered, covered, sched_group_span(sg)); 1214 1215 if (!first) 1216 first = sg; 1217 if (last) 1218 last->next = sg; 1219 last = sg; 1220 } 1221 last->next = first; 1222 sd->groups = first; 1223 1224 return 0; 1225 } 1226 1227 /* 1228 * Initialize sched groups cpu_capacity. 1229 * 1230 * cpu_capacity indicates the capacity of sched group, which is used while 1231 * distributing the load between different sched groups in a sched domain. 1232 * Typically cpu_capacity for all the groups in a sched domain will be same 1233 * unless there are asymmetries in the topology. If there are asymmetries, 1234 * group having more cpu_capacity will pickup more load compared to the 1235 * group having less cpu_capacity. 1236 */ 1237 static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) 1238 { 1239 struct sched_group *sg = sd->groups; 1240 1241 WARN_ON(!sg); 1242 1243 do { 1244 int cpu, max_cpu = -1; 1245 1246 sg->group_weight = cpumask_weight(sched_group_span(sg)); 1247 1248 if (!(sd->flags & SD_ASYM_PACKING)) 1249 goto next; 1250 1251 for_each_cpu(cpu, sched_group_span(sg)) { 1252 if (max_cpu < 0) 1253 max_cpu = cpu; 1254 else if (sched_asym_prefer(cpu, max_cpu)) 1255 max_cpu = cpu; 1256 } 1257 sg->asym_prefer_cpu = max_cpu; 1258 1259 next: 1260 sg = sg->next; 1261 } while (sg != sd->groups); 1262 1263 if (cpu != group_balance_cpu(sg)) 1264 return; 1265 1266 update_group_capacity(sd, cpu); 1267 } 1268 1269 /* 1270 * Initializers for schedule domains 1271 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 1272 */ 1273 1274 static int default_relax_domain_level = -1; 1275 int sched_domain_level_max; 1276 1277 static int __init setup_relax_domain_level(char *str) 1278 { 1279 if (kstrtoint(str, 0, &default_relax_domain_level)) 1280 pr_warn("Unable to set relax_domain_level\n"); 1281 1282 return 1; 1283 } 1284 __setup("relax_domain_level=", setup_relax_domain_level); 1285 1286 static void set_domain_attribute(struct sched_domain *sd, 1287 struct sched_domain_attr *attr) 1288 { 1289 int request; 1290 1291 if (!attr || attr->relax_domain_level < 0) { 1292 if (default_relax_domain_level < 0) 1293 return; 1294 request = default_relax_domain_level; 1295 } else 1296 request = attr->relax_domain_level; 1297 1298 if (sd->level > request) { 1299 /* Turn off idle balance on this domain: */ 1300 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 1301 } 1302 } 1303 1304 static void __sdt_free(const struct cpumask *cpu_map); 1305 static int __sdt_alloc(const struct cpumask *cpu_map); 1306 1307 static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 1308 const struct cpumask *cpu_map) 1309 { 1310 switch (what) { 1311 case sa_rootdomain: 1312 if (!atomic_read(&d->rd->refcount)) 1313 free_rootdomain(&d->rd->rcu); 1314 fallthrough; 1315 case sa_sd: 1316 free_percpu(d->sd); 1317 fallthrough; 1318 case sa_sd_storage: 1319 __sdt_free(cpu_map); 1320 fallthrough; 1321 case sa_none: 1322 break; 1323 } 1324 } 1325 1326 static enum s_alloc 1327 __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) 1328 { 1329 memset(d, 0, sizeof(*d)); 1330 1331 if (__sdt_alloc(cpu_map)) 1332 return sa_sd_storage; 1333 d->sd = alloc_percpu(struct sched_domain *); 1334 if (!d->sd) 1335 return sa_sd_storage; 1336 d->rd = alloc_rootdomain(); 1337 if (!d->rd) 1338 return sa_sd; 1339 1340 return sa_rootdomain; 1341 } 1342 1343 /* 1344 * NULL the sd_data elements we've used to build the sched_domain and 1345 * sched_group structure so that the subsequent __free_domain_allocs() 1346 * will not free the data we're using. 1347 */ 1348 static void claim_allocations(int cpu, struct sched_domain *sd) 1349 { 1350 struct sd_data *sdd = sd->private; 1351 1352 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 1353 *per_cpu_ptr(sdd->sd, cpu) = NULL; 1354 1355 if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref)) 1356 *per_cpu_ptr(sdd->sds, cpu) = NULL; 1357 1358 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 1359 *per_cpu_ptr(sdd->sg, cpu) = NULL; 1360 1361 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) 1362 *per_cpu_ptr(sdd->sgc, cpu) = NULL; 1363 } 1364 1365 #ifdef CONFIG_NUMA 1366 enum numa_topology_type sched_numa_topology_type; 1367 1368 static int sched_domains_numa_levels; 1369 static int sched_domains_curr_level; 1370 1371 int sched_max_numa_distance; 1372 static int *sched_domains_numa_distance; 1373 static struct cpumask ***sched_domains_numa_masks; 1374 int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE; 1375 #endif 1376 1377 /* 1378 * SD_flags allowed in topology descriptions. 1379 * 1380 * These flags are purely descriptive of the topology and do not prescribe 1381 * behaviour. Behaviour is artificial and mapped in the below sd_init() 1382 * function: 1383 * 1384 * SD_SHARE_CPUCAPACITY - describes SMT topologies 1385 * SD_SHARE_PKG_RESOURCES - describes shared caches 1386 * SD_NUMA - describes NUMA topologies 1387 * 1388 * Odd one out, which beside describing the topology has a quirk also 1389 * prescribes the desired behaviour that goes along with it: 1390 * 1391 * SD_ASYM_PACKING - describes SMT quirks 1392 */ 1393 #define TOPOLOGY_SD_FLAGS \ 1394 (SD_SHARE_CPUCAPACITY | \ 1395 SD_SHARE_PKG_RESOURCES | \ 1396 SD_NUMA | \ 1397 SD_ASYM_PACKING) 1398 1399 static struct sched_domain * 1400 sd_init(struct sched_domain_topology_level *tl, 1401 const struct cpumask *cpu_map, 1402 struct sched_domain *child, int dflags, int cpu) 1403 { 1404 struct sd_data *sdd = &tl->data; 1405 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 1406 int sd_id, sd_weight, sd_flags = 0; 1407 1408 #ifdef CONFIG_NUMA 1409 /* 1410 * Ugly hack to pass state to sd_numa_mask()... 1411 */ 1412 sched_domains_curr_level = tl->numa_level; 1413 #endif 1414 1415 sd_weight = cpumask_weight(tl->mask(cpu)); 1416 1417 if (tl->sd_flags) 1418 sd_flags = (*tl->sd_flags)(); 1419 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, 1420 "wrong sd_flags in topology description\n")) 1421 sd_flags &= TOPOLOGY_SD_FLAGS; 1422 1423 /* Apply detected topology flags */ 1424 sd_flags |= dflags; 1425 1426 *sd = (struct sched_domain){ 1427 .min_interval = sd_weight, 1428 .max_interval = 2*sd_weight, 1429 .busy_factor = 16, 1430 .imbalance_pct = 117, 1431 1432 .cache_nice_tries = 0, 1433 1434 .flags = 1*SD_BALANCE_NEWIDLE 1435 | 1*SD_BALANCE_EXEC 1436 | 1*SD_BALANCE_FORK 1437 | 0*SD_BALANCE_WAKE 1438 | 1*SD_WAKE_AFFINE 1439 | 0*SD_SHARE_CPUCAPACITY 1440 | 0*SD_SHARE_PKG_RESOURCES 1441 | 0*SD_SERIALIZE 1442 | 1*SD_PREFER_SIBLING 1443 | 0*SD_NUMA 1444 | sd_flags 1445 , 1446 1447 .last_balance = jiffies, 1448 .balance_interval = sd_weight, 1449 .max_newidle_lb_cost = 0, 1450 .next_decay_max_lb_cost = jiffies, 1451 .child = child, 1452 #ifdef CONFIG_SCHED_DEBUG 1453 .name = tl->name, 1454 #endif 1455 }; 1456 1457 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 1458 sd_id = cpumask_first(sched_domain_span(sd)); 1459 1460 /* 1461 * Convert topological properties into behaviour. 1462 */ 1463 1464 /* Don't attempt to spread across CPUs of different capacities. */ 1465 if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child) 1466 sd->child->flags &= ~SD_PREFER_SIBLING; 1467 1468 if (sd->flags & SD_SHARE_CPUCAPACITY) { 1469 sd->imbalance_pct = 110; 1470 1471 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { 1472 sd->imbalance_pct = 117; 1473 sd->cache_nice_tries = 1; 1474 1475 #ifdef CONFIG_NUMA 1476 } else if (sd->flags & SD_NUMA) { 1477 sd->cache_nice_tries = 2; 1478 1479 sd->flags &= ~SD_PREFER_SIBLING; 1480 sd->flags |= SD_SERIALIZE; 1481 if (sched_domains_numa_distance[tl->numa_level] > node_reclaim_distance) { 1482 sd->flags &= ~(SD_BALANCE_EXEC | 1483 SD_BALANCE_FORK | 1484 SD_WAKE_AFFINE); 1485 } 1486 1487 #endif 1488 } else { 1489 sd->cache_nice_tries = 1; 1490 } 1491 1492 /* 1493 * For all levels sharing cache; connect a sched_domain_shared 1494 * instance. 1495 */ 1496 if (sd->flags & SD_SHARE_PKG_RESOURCES) { 1497 sd->shared = *per_cpu_ptr(sdd->sds, sd_id); 1498 atomic_inc(&sd->shared->ref); 1499 atomic_set(&sd->shared->nr_busy_cpus, sd_weight); 1500 } 1501 1502 sd->private = sdd; 1503 1504 return sd; 1505 } 1506 1507 /* 1508 * Topology list, bottom-up. 1509 */ 1510 static struct sched_domain_topology_level default_topology[] = { 1511 #ifdef CONFIG_SCHED_SMT 1512 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, 1513 #endif 1514 #ifdef CONFIG_SCHED_MC 1515 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, 1516 #endif 1517 { cpu_cpu_mask, SD_INIT_NAME(DIE) }, 1518 { NULL, }, 1519 }; 1520 1521 static struct sched_domain_topology_level *sched_domain_topology = 1522 default_topology; 1523 1524 #define for_each_sd_topology(tl) \ 1525 for (tl = sched_domain_topology; tl->mask; tl++) 1526 1527 void set_sched_topology(struct sched_domain_topology_level *tl) 1528 { 1529 if (WARN_ON_ONCE(sched_smp_initialized)) 1530 return; 1531 1532 sched_domain_topology = tl; 1533 } 1534 1535 #ifdef CONFIG_NUMA 1536 1537 static const struct cpumask *sd_numa_mask(int cpu) 1538 { 1539 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 1540 } 1541 1542 static void sched_numa_warn(const char *str) 1543 { 1544 static int done = false; 1545 int i,j; 1546 1547 if (done) 1548 return; 1549 1550 done = true; 1551 1552 printk(KERN_WARNING "ERROR: %s\n\n", str); 1553 1554 for (i = 0; i < nr_node_ids; i++) { 1555 printk(KERN_WARNING " "); 1556 for (j = 0; j < nr_node_ids; j++) 1557 printk(KERN_CONT "%02d ", node_distance(i,j)); 1558 printk(KERN_CONT "\n"); 1559 } 1560 printk(KERN_WARNING "\n"); 1561 } 1562 1563 bool find_numa_distance(int distance) 1564 { 1565 int i; 1566 1567 if (distance == node_distance(0, 0)) 1568 return true; 1569 1570 for (i = 0; i < sched_domains_numa_levels; i++) { 1571 if (sched_domains_numa_distance[i] == distance) 1572 return true; 1573 } 1574 1575 return false; 1576 } 1577 1578 /* 1579 * A system can have three types of NUMA topology: 1580 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system 1581 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes 1582 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane 1583 * 1584 * The difference between a glueless mesh topology and a backplane 1585 * topology lies in whether communication between not directly 1586 * connected nodes goes through intermediary nodes (where programs 1587 * could run), or through backplane controllers. This affects 1588 * placement of programs. 1589 * 1590 * The type of topology can be discerned with the following tests: 1591 * - If the maximum distance between any nodes is 1 hop, the system 1592 * is directly connected. 1593 * - If for two nodes A and B, located N > 1 hops away from each other, 1594 * there is an intermediary node C, which is < N hops away from both 1595 * nodes A and B, the system is a glueless mesh. 1596 */ 1597 static void init_numa_topology_type(void) 1598 { 1599 int a, b, c, n; 1600 1601 n = sched_max_numa_distance; 1602 1603 if (sched_domains_numa_levels <= 2) { 1604 sched_numa_topology_type = NUMA_DIRECT; 1605 return; 1606 } 1607 1608 for_each_online_node(a) { 1609 for_each_online_node(b) { 1610 /* Find two nodes furthest removed from each other. */ 1611 if (node_distance(a, b) < n) 1612 continue; 1613 1614 /* Is there an intermediary node between a and b? */ 1615 for_each_online_node(c) { 1616 if (node_distance(a, c) < n && 1617 node_distance(b, c) < n) { 1618 sched_numa_topology_type = 1619 NUMA_GLUELESS_MESH; 1620 return; 1621 } 1622 } 1623 1624 sched_numa_topology_type = NUMA_BACKPLANE; 1625 return; 1626 } 1627 } 1628 } 1629 1630 1631 #define NR_DISTANCE_VALUES (1 << DISTANCE_BITS) 1632 1633 void sched_init_numa(void) 1634 { 1635 struct sched_domain_topology_level *tl; 1636 unsigned long *distance_map; 1637 int nr_levels = 0; 1638 int i, j; 1639 1640 /* 1641 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 1642 * unique distances in the node_distance() table. 1643 */ 1644 distance_map = bitmap_alloc(NR_DISTANCE_VALUES, GFP_KERNEL); 1645 if (!distance_map) 1646 return; 1647 1648 bitmap_zero(distance_map, NR_DISTANCE_VALUES); 1649 for (i = 0; i < nr_node_ids; i++) { 1650 for (j = 0; j < nr_node_ids; j++) { 1651 int distance = node_distance(i, j); 1652 1653 if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) { 1654 sched_numa_warn("Invalid distance value range"); 1655 return; 1656 } 1657 1658 bitmap_set(distance_map, distance, 1); 1659 } 1660 } 1661 /* 1662 * We can now figure out how many unique distance values there are and 1663 * allocate memory accordingly. 1664 */ 1665 nr_levels = bitmap_weight(distance_map, NR_DISTANCE_VALUES); 1666 1667 sched_domains_numa_distance = kcalloc(nr_levels, sizeof(int), GFP_KERNEL); 1668 if (!sched_domains_numa_distance) { 1669 bitmap_free(distance_map); 1670 return; 1671 } 1672 1673 for (i = 0, j = 0; i < nr_levels; i++, j++) { 1674 j = find_next_bit(distance_map, NR_DISTANCE_VALUES, j); 1675 sched_domains_numa_distance[i] = j; 1676 } 1677 1678 bitmap_free(distance_map); 1679 1680 /* 1681 * 'nr_levels' contains the number of unique distances 1682 * 1683 * The sched_domains_numa_distance[] array includes the actual distance 1684 * numbers. 1685 */ 1686 1687 /* 1688 * Here, we should temporarily reset sched_domains_numa_levels to 0. 1689 * If it fails to allocate memory for array sched_domains_numa_masks[][], 1690 * the array will contain less then 'nr_levels' members. This could be 1691 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 1692 * in other functions. 1693 * 1694 * We reset it to 'nr_levels' at the end of this function. 1695 */ 1696 sched_domains_numa_levels = 0; 1697 1698 sched_domains_numa_masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL); 1699 if (!sched_domains_numa_masks) 1700 return; 1701 1702 /* 1703 * Now for each level, construct a mask per node which contains all 1704 * CPUs of nodes that are that many hops away from us. 1705 */ 1706 for (i = 0; i < nr_levels; i++) { 1707 sched_domains_numa_masks[i] = 1708 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 1709 if (!sched_domains_numa_masks[i]) 1710 return; 1711 1712 for (j = 0; j < nr_node_ids; j++) { 1713 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 1714 int k; 1715 1716 if (!mask) 1717 return; 1718 1719 sched_domains_numa_masks[i][j] = mask; 1720 1721 for_each_node(k) { 1722 if (sched_debug() && (node_distance(j, k) != node_distance(k, j))) 1723 sched_numa_warn("Node-distance not symmetric"); 1724 1725 if (node_distance(j, k) > sched_domains_numa_distance[i]) 1726 continue; 1727 1728 cpumask_or(mask, mask, cpumask_of_node(k)); 1729 } 1730 } 1731 } 1732 1733 /* Compute default topology size */ 1734 for (i = 0; sched_domain_topology[i].mask; i++); 1735 1736 tl = kzalloc((i + nr_levels + 1) * 1737 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 1738 if (!tl) 1739 return; 1740 1741 /* 1742 * Copy the default topology bits.. 1743 */ 1744 for (i = 0; sched_domain_topology[i].mask; i++) 1745 tl[i] = sched_domain_topology[i]; 1746 1747 /* 1748 * Add the NUMA identity distance, aka single NODE. 1749 */ 1750 tl[i++] = (struct sched_domain_topology_level){ 1751 .mask = sd_numa_mask, 1752 .numa_level = 0, 1753 SD_INIT_NAME(NODE) 1754 }; 1755 1756 /* 1757 * .. and append 'j' levels of NUMA goodness. 1758 */ 1759 for (j = 1; j < nr_levels; i++, j++) { 1760 tl[i] = (struct sched_domain_topology_level){ 1761 .mask = sd_numa_mask, 1762 .sd_flags = cpu_numa_flags, 1763 .flags = SDTL_OVERLAP, 1764 .numa_level = j, 1765 SD_INIT_NAME(NUMA) 1766 }; 1767 } 1768 1769 sched_domain_topology = tl; 1770 1771 sched_domains_numa_levels = nr_levels; 1772 sched_max_numa_distance = sched_domains_numa_distance[nr_levels - 1]; 1773 1774 init_numa_topology_type(); 1775 } 1776 1777 void sched_domains_numa_masks_set(unsigned int cpu) 1778 { 1779 int node = cpu_to_node(cpu); 1780 int i, j; 1781 1782 for (i = 0; i < sched_domains_numa_levels; i++) { 1783 for (j = 0; j < nr_node_ids; j++) { 1784 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 1785 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 1786 } 1787 } 1788 } 1789 1790 void sched_domains_numa_masks_clear(unsigned int cpu) 1791 { 1792 int i, j; 1793 1794 for (i = 0; i < sched_domains_numa_levels; i++) { 1795 for (j = 0; j < nr_node_ids; j++) 1796 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 1797 } 1798 } 1799 1800 /* 1801 * sched_numa_find_closest() - given the NUMA topology, find the cpu 1802 * closest to @cpu from @cpumask. 1803 * cpumask: cpumask to find a cpu from 1804 * cpu: cpu to be close to 1805 * 1806 * returns: cpu, or nr_cpu_ids when nothing found. 1807 */ 1808 int sched_numa_find_closest(const struct cpumask *cpus, int cpu) 1809 { 1810 int i, j = cpu_to_node(cpu); 1811 1812 for (i = 0; i < sched_domains_numa_levels; i++) { 1813 cpu = cpumask_any_and(cpus, sched_domains_numa_masks[i][j]); 1814 if (cpu < nr_cpu_ids) 1815 return cpu; 1816 } 1817 return nr_cpu_ids; 1818 } 1819 1820 #endif /* CONFIG_NUMA */ 1821 1822 static int __sdt_alloc(const struct cpumask *cpu_map) 1823 { 1824 struct sched_domain_topology_level *tl; 1825 int j; 1826 1827 for_each_sd_topology(tl) { 1828 struct sd_data *sdd = &tl->data; 1829 1830 sdd->sd = alloc_percpu(struct sched_domain *); 1831 if (!sdd->sd) 1832 return -ENOMEM; 1833 1834 sdd->sds = alloc_percpu(struct sched_domain_shared *); 1835 if (!sdd->sds) 1836 return -ENOMEM; 1837 1838 sdd->sg = alloc_percpu(struct sched_group *); 1839 if (!sdd->sg) 1840 return -ENOMEM; 1841 1842 sdd->sgc = alloc_percpu(struct sched_group_capacity *); 1843 if (!sdd->sgc) 1844 return -ENOMEM; 1845 1846 for_each_cpu(j, cpu_map) { 1847 struct sched_domain *sd; 1848 struct sched_domain_shared *sds; 1849 struct sched_group *sg; 1850 struct sched_group_capacity *sgc; 1851 1852 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 1853 GFP_KERNEL, cpu_to_node(j)); 1854 if (!sd) 1855 return -ENOMEM; 1856 1857 *per_cpu_ptr(sdd->sd, j) = sd; 1858 1859 sds = kzalloc_node(sizeof(struct sched_domain_shared), 1860 GFP_KERNEL, cpu_to_node(j)); 1861 if (!sds) 1862 return -ENOMEM; 1863 1864 *per_cpu_ptr(sdd->sds, j) = sds; 1865 1866 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 1867 GFP_KERNEL, cpu_to_node(j)); 1868 if (!sg) 1869 return -ENOMEM; 1870 1871 sg->next = sg; 1872 1873 *per_cpu_ptr(sdd->sg, j) = sg; 1874 1875 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), 1876 GFP_KERNEL, cpu_to_node(j)); 1877 if (!sgc) 1878 return -ENOMEM; 1879 1880 #ifdef CONFIG_SCHED_DEBUG 1881 sgc->id = j; 1882 #endif 1883 1884 *per_cpu_ptr(sdd->sgc, j) = sgc; 1885 } 1886 } 1887 1888 return 0; 1889 } 1890 1891 static void __sdt_free(const struct cpumask *cpu_map) 1892 { 1893 struct sched_domain_topology_level *tl; 1894 int j; 1895 1896 for_each_sd_topology(tl) { 1897 struct sd_data *sdd = &tl->data; 1898 1899 for_each_cpu(j, cpu_map) { 1900 struct sched_domain *sd; 1901 1902 if (sdd->sd) { 1903 sd = *per_cpu_ptr(sdd->sd, j); 1904 if (sd && (sd->flags & SD_OVERLAP)) 1905 free_sched_groups(sd->groups, 0); 1906 kfree(*per_cpu_ptr(sdd->sd, j)); 1907 } 1908 1909 if (sdd->sds) 1910 kfree(*per_cpu_ptr(sdd->sds, j)); 1911 if (sdd->sg) 1912 kfree(*per_cpu_ptr(sdd->sg, j)); 1913 if (sdd->sgc) 1914 kfree(*per_cpu_ptr(sdd->sgc, j)); 1915 } 1916 free_percpu(sdd->sd); 1917 sdd->sd = NULL; 1918 free_percpu(sdd->sds); 1919 sdd->sds = NULL; 1920 free_percpu(sdd->sg); 1921 sdd->sg = NULL; 1922 free_percpu(sdd->sgc); 1923 sdd->sgc = NULL; 1924 } 1925 } 1926 1927 static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 1928 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 1929 struct sched_domain *child, int dflags, int cpu) 1930 { 1931 struct sched_domain *sd = sd_init(tl, cpu_map, child, dflags, cpu); 1932 1933 if (child) { 1934 sd->level = child->level + 1; 1935 sched_domain_level_max = max(sched_domain_level_max, sd->level); 1936 child->parent = sd; 1937 1938 if (!cpumask_subset(sched_domain_span(child), 1939 sched_domain_span(sd))) { 1940 pr_err("BUG: arch topology borken\n"); 1941 #ifdef CONFIG_SCHED_DEBUG 1942 pr_err(" the %s domain not a subset of the %s domain\n", 1943 child->name, sd->name); 1944 #endif 1945 /* Fixup, ensure @sd has at least @child CPUs. */ 1946 cpumask_or(sched_domain_span(sd), 1947 sched_domain_span(sd), 1948 sched_domain_span(child)); 1949 } 1950 1951 } 1952 set_domain_attribute(sd, attr); 1953 1954 return sd; 1955 } 1956 1957 /* 1958 * Ensure topology masks are sane, i.e. there are no conflicts (overlaps) for 1959 * any two given CPUs at this (non-NUMA) topology level. 1960 */ 1961 static bool topology_span_sane(struct sched_domain_topology_level *tl, 1962 const struct cpumask *cpu_map, int cpu) 1963 { 1964 int i; 1965 1966 /* NUMA levels are allowed to overlap */ 1967 if (tl->flags & SDTL_OVERLAP) 1968 return true; 1969 1970 /* 1971 * Non-NUMA levels cannot partially overlap - they must be either 1972 * completely equal or completely disjoint. Otherwise we can end up 1973 * breaking the sched_group lists - i.e. a later get_group() pass 1974 * breaks the linking done for an earlier span. 1975 */ 1976 for_each_cpu(i, cpu_map) { 1977 if (i == cpu) 1978 continue; 1979 /* 1980 * We should 'and' all those masks with 'cpu_map' to exactly 1981 * match the topology we're about to build, but that can only 1982 * remove CPUs, which only lessens our ability to detect 1983 * overlaps 1984 */ 1985 if (!cpumask_equal(tl->mask(cpu), tl->mask(i)) && 1986 cpumask_intersects(tl->mask(cpu), tl->mask(i))) 1987 return false; 1988 } 1989 1990 return true; 1991 } 1992 1993 /* 1994 * Find the sched_domain_topology_level where all CPU capacities are visible 1995 * for all CPUs. 1996 */ 1997 static struct sched_domain_topology_level 1998 *asym_cpu_capacity_level(const struct cpumask *cpu_map) 1999 { 2000 int i, j, asym_level = 0; 2001 bool asym = false; 2002 struct sched_domain_topology_level *tl, *asym_tl = NULL; 2003 unsigned long cap; 2004 2005 /* Is there any asymmetry? */ 2006 cap = arch_scale_cpu_capacity(cpumask_first(cpu_map)); 2007 2008 for_each_cpu(i, cpu_map) { 2009 if (arch_scale_cpu_capacity(i) != cap) { 2010 asym = true; 2011 break; 2012 } 2013 } 2014 2015 if (!asym) 2016 return NULL; 2017 2018 /* 2019 * Examine topology from all CPU's point of views to detect the lowest 2020 * sched_domain_topology_level where a highest capacity CPU is visible 2021 * to everyone. 2022 */ 2023 for_each_cpu(i, cpu_map) { 2024 unsigned long max_capacity = arch_scale_cpu_capacity(i); 2025 int tl_id = 0; 2026 2027 for_each_sd_topology(tl) { 2028 if (tl_id < asym_level) 2029 goto next_level; 2030 2031 for_each_cpu_and(j, tl->mask(i), cpu_map) { 2032 unsigned long capacity; 2033 2034 capacity = arch_scale_cpu_capacity(j); 2035 2036 if (capacity <= max_capacity) 2037 continue; 2038 2039 max_capacity = capacity; 2040 asym_level = tl_id; 2041 asym_tl = tl; 2042 } 2043 next_level: 2044 tl_id++; 2045 } 2046 } 2047 2048 return asym_tl; 2049 } 2050 2051 2052 /* 2053 * Build sched domains for a given set of CPUs and attach the sched domains 2054 * to the individual CPUs 2055 */ 2056 static int 2057 build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr) 2058 { 2059 enum s_alloc alloc_state = sa_none; 2060 struct sched_domain *sd; 2061 struct s_data d; 2062 struct rq *rq = NULL; 2063 int i, ret = -ENOMEM; 2064 struct sched_domain_topology_level *tl_asym; 2065 bool has_asym = false; 2066 2067 if (WARN_ON(cpumask_empty(cpu_map))) 2068 goto error; 2069 2070 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 2071 if (alloc_state != sa_rootdomain) 2072 goto error; 2073 2074 tl_asym = asym_cpu_capacity_level(cpu_map); 2075 2076 /* Set up domains for CPUs specified by the cpu_map: */ 2077 for_each_cpu(i, cpu_map) { 2078 struct sched_domain_topology_level *tl; 2079 int dflags = 0; 2080 2081 sd = NULL; 2082 for_each_sd_topology(tl) { 2083 if (tl == tl_asym) { 2084 dflags |= SD_ASYM_CPUCAPACITY; 2085 has_asym = true; 2086 } 2087 2088 if (WARN_ON(!topology_span_sane(tl, cpu_map, i))) 2089 goto error; 2090 2091 sd = build_sched_domain(tl, cpu_map, attr, sd, dflags, i); 2092 2093 if (tl == sched_domain_topology) 2094 *per_cpu_ptr(d.sd, i) = sd; 2095 if (tl->flags & SDTL_OVERLAP) 2096 sd->flags |= SD_OVERLAP; 2097 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 2098 break; 2099 } 2100 } 2101 2102 /* Build the groups for the domains */ 2103 for_each_cpu(i, cpu_map) { 2104 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 2105 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 2106 if (sd->flags & SD_OVERLAP) { 2107 if (build_overlap_sched_groups(sd, i)) 2108 goto error; 2109 } else { 2110 if (build_sched_groups(sd, i)) 2111 goto error; 2112 } 2113 } 2114 } 2115 2116 /* Calculate CPU capacity for physical packages and nodes */ 2117 for (i = nr_cpumask_bits-1; i >= 0; i--) { 2118 if (!cpumask_test_cpu(i, cpu_map)) 2119 continue; 2120 2121 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 2122 claim_allocations(i, sd); 2123 init_sched_groups_capacity(i, sd); 2124 } 2125 } 2126 2127 /* Attach the domains */ 2128 rcu_read_lock(); 2129 for_each_cpu(i, cpu_map) { 2130 rq = cpu_rq(i); 2131 sd = *per_cpu_ptr(d.sd, i); 2132 2133 /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */ 2134 if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity)) 2135 WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig); 2136 2137 cpu_attach_domain(sd, d.rd, i); 2138 } 2139 rcu_read_unlock(); 2140 2141 if (has_asym) 2142 static_branch_inc_cpuslocked(&sched_asym_cpucapacity); 2143 2144 if (rq && sched_debug_verbose) { 2145 pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", 2146 cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); 2147 } 2148 2149 ret = 0; 2150 error: 2151 __free_domain_allocs(&d, alloc_state, cpu_map); 2152 2153 return ret; 2154 } 2155 2156 /* Current sched domains: */ 2157 static cpumask_var_t *doms_cur; 2158 2159 /* Number of sched domains in 'doms_cur': */ 2160 static int ndoms_cur; 2161 2162 /* Attributes of custom domains in 'doms_cur' */ 2163 static struct sched_domain_attr *dattr_cur; 2164 2165 /* 2166 * Special case: If a kmalloc() of a doms_cur partition (array of 2167 * cpumask) fails, then fallback to a single sched domain, 2168 * as determined by the single cpumask fallback_doms. 2169 */ 2170 static cpumask_var_t fallback_doms; 2171 2172 /* 2173 * arch_update_cpu_topology lets virtualized architectures update the 2174 * CPU core maps. It is supposed to return 1 if the topology changed 2175 * or 0 if it stayed the same. 2176 */ 2177 int __weak arch_update_cpu_topology(void) 2178 { 2179 return 0; 2180 } 2181 2182 cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 2183 { 2184 int i; 2185 cpumask_var_t *doms; 2186 2187 doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL); 2188 if (!doms) 2189 return NULL; 2190 for (i = 0; i < ndoms; i++) { 2191 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 2192 free_sched_domains(doms, i); 2193 return NULL; 2194 } 2195 } 2196 return doms; 2197 } 2198 2199 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 2200 { 2201 unsigned int i; 2202 for (i = 0; i < ndoms; i++) 2203 free_cpumask_var(doms[i]); 2204 kfree(doms); 2205 } 2206 2207 /* 2208 * Set up scheduler domains and groups. For now this just excludes isolated 2209 * CPUs, but could be used to exclude other special cases in the future. 2210 */ 2211 int sched_init_domains(const struct cpumask *cpu_map) 2212 { 2213 int err; 2214 2215 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL); 2216 zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL); 2217 zalloc_cpumask_var(&fallback_doms, GFP_KERNEL); 2218 2219 arch_update_cpu_topology(); 2220 ndoms_cur = 1; 2221 doms_cur = alloc_sched_domains(ndoms_cur); 2222 if (!doms_cur) 2223 doms_cur = &fallback_doms; 2224 cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN)); 2225 err = build_sched_domains(doms_cur[0], NULL); 2226 2227 return err; 2228 } 2229 2230 /* 2231 * Detach sched domains from a group of CPUs specified in cpu_map 2232 * These CPUs will now be attached to the NULL domain 2233 */ 2234 static void detach_destroy_domains(const struct cpumask *cpu_map) 2235 { 2236 unsigned int cpu = cpumask_any(cpu_map); 2237 int i; 2238 2239 if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu))) 2240 static_branch_dec_cpuslocked(&sched_asym_cpucapacity); 2241 2242 rcu_read_lock(); 2243 for_each_cpu(i, cpu_map) 2244 cpu_attach_domain(NULL, &def_root_domain, i); 2245 rcu_read_unlock(); 2246 } 2247 2248 /* handle null as "default" */ 2249 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 2250 struct sched_domain_attr *new, int idx_new) 2251 { 2252 struct sched_domain_attr tmp; 2253 2254 /* Fast path: */ 2255 if (!new && !cur) 2256 return 1; 2257 2258 tmp = SD_ATTR_INIT; 2259 2260 return !memcmp(cur ? (cur + idx_cur) : &tmp, 2261 new ? (new + idx_new) : &tmp, 2262 sizeof(struct sched_domain_attr)); 2263 } 2264 2265 /* 2266 * Partition sched domains as specified by the 'ndoms_new' 2267 * cpumasks in the array doms_new[] of cpumasks. This compares 2268 * doms_new[] to the current sched domain partitioning, doms_cur[]. 2269 * It destroys each deleted domain and builds each new domain. 2270 * 2271 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 2272 * The masks don't intersect (don't overlap.) We should setup one 2273 * sched domain for each mask. CPUs not in any of the cpumasks will 2274 * not be load balanced. If the same cpumask appears both in the 2275 * current 'doms_cur' domains and in the new 'doms_new', we can leave 2276 * it as it is. 2277 * 2278 * The passed in 'doms_new' should be allocated using 2279 * alloc_sched_domains. This routine takes ownership of it and will 2280 * free_sched_domains it when done with it. If the caller failed the 2281 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 2282 * and partition_sched_domains() will fallback to the single partition 2283 * 'fallback_doms', it also forces the domains to be rebuilt. 2284 * 2285 * If doms_new == NULL it will be replaced with cpu_online_mask. 2286 * ndoms_new == 0 is a special case for destroying existing domains, 2287 * and it will not create the default domain. 2288 * 2289 * Call with hotplug lock and sched_domains_mutex held 2290 */ 2291 void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[], 2292 struct sched_domain_attr *dattr_new) 2293 { 2294 bool __maybe_unused has_eas = false; 2295 int i, j, n; 2296 int new_topology; 2297 2298 lockdep_assert_held(&sched_domains_mutex); 2299 2300 /* Let the architecture update CPU core mappings: */ 2301 new_topology = arch_update_cpu_topology(); 2302 2303 if (!doms_new) { 2304 WARN_ON_ONCE(dattr_new); 2305 n = 0; 2306 doms_new = alloc_sched_domains(1); 2307 if (doms_new) { 2308 n = 1; 2309 cpumask_and(doms_new[0], cpu_active_mask, 2310 housekeeping_cpumask(HK_FLAG_DOMAIN)); 2311 } 2312 } else { 2313 n = ndoms_new; 2314 } 2315 2316 /* Destroy deleted domains: */ 2317 for (i = 0; i < ndoms_cur; i++) { 2318 for (j = 0; j < n && !new_topology; j++) { 2319 if (cpumask_equal(doms_cur[i], doms_new[j]) && 2320 dattrs_equal(dattr_cur, i, dattr_new, j)) { 2321 struct root_domain *rd; 2322 2323 /* 2324 * This domain won't be destroyed and as such 2325 * its dl_bw->total_bw needs to be cleared. It 2326 * will be recomputed in function 2327 * update_tasks_root_domain(). 2328 */ 2329 rd = cpu_rq(cpumask_any(doms_cur[i]))->rd; 2330 dl_clear_root_domain(rd); 2331 goto match1; 2332 } 2333 } 2334 /* No match - a current sched domain not in new doms_new[] */ 2335 detach_destroy_domains(doms_cur[i]); 2336 match1: 2337 ; 2338 } 2339 2340 n = ndoms_cur; 2341 if (!doms_new) { 2342 n = 0; 2343 doms_new = &fallback_doms; 2344 cpumask_and(doms_new[0], cpu_active_mask, 2345 housekeeping_cpumask(HK_FLAG_DOMAIN)); 2346 } 2347 2348 /* Build new domains: */ 2349 for (i = 0; i < ndoms_new; i++) { 2350 for (j = 0; j < n && !new_topology; j++) { 2351 if (cpumask_equal(doms_new[i], doms_cur[j]) && 2352 dattrs_equal(dattr_new, i, dattr_cur, j)) 2353 goto match2; 2354 } 2355 /* No match - add a new doms_new */ 2356 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 2357 match2: 2358 ; 2359 } 2360 2361 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) 2362 /* Build perf. domains: */ 2363 for (i = 0; i < ndoms_new; i++) { 2364 for (j = 0; j < n && !sched_energy_update; j++) { 2365 if (cpumask_equal(doms_new[i], doms_cur[j]) && 2366 cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) { 2367 has_eas = true; 2368 goto match3; 2369 } 2370 } 2371 /* No match - add perf. domains for a new rd */ 2372 has_eas |= build_perf_domains(doms_new[i]); 2373 match3: 2374 ; 2375 } 2376 sched_energy_set(has_eas); 2377 #endif 2378 2379 /* Remember the new sched domains: */ 2380 if (doms_cur != &fallback_doms) 2381 free_sched_domains(doms_cur, ndoms_cur); 2382 2383 kfree(dattr_cur); 2384 doms_cur = doms_new; 2385 dattr_cur = dattr_new; 2386 ndoms_cur = ndoms_new; 2387 2388 update_sched_domain_debugfs(); 2389 } 2390 2391 /* 2392 * Call with hotplug lock held 2393 */ 2394 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 2395 struct sched_domain_attr *dattr_new) 2396 { 2397 mutex_lock(&sched_domains_mutex); 2398 partition_sched_domains_locked(ndoms_new, doms_new, dattr_new); 2399 mutex_unlock(&sched_domains_mutex); 2400 } 2401