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 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 29 struct cpumask *groupmask) 30 { 31 struct sched_group *group = sd->groups; 32 33 cpumask_clear(groupmask); 34 35 printk(KERN_DEBUG "%*s domain-%d: ", level, "", level); 36 37 if (!(sd->flags & SD_LOAD_BALANCE)) { 38 printk("does not load-balance\n"); 39 if (sd->parent) 40 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain has parent"); 41 return -1; 42 } 43 44 printk(KERN_CONT "span=%*pbl level=%s\n", 45 cpumask_pr_args(sched_domain_span(sd)), sd->name); 46 47 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 48 printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu); 49 } 50 if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) { 51 printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu); 52 } 53 54 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 55 do { 56 if (!group) { 57 printk("\n"); 58 printk(KERN_ERR "ERROR: group is NULL\n"); 59 break; 60 } 61 62 if (!cpumask_weight(sched_group_span(group))) { 63 printk(KERN_CONT "\n"); 64 printk(KERN_ERR "ERROR: empty group\n"); 65 break; 66 } 67 68 if (!(sd->flags & SD_OVERLAP) && 69 cpumask_intersects(groupmask, sched_group_span(group))) { 70 printk(KERN_CONT "\n"); 71 printk(KERN_ERR "ERROR: repeated CPUs\n"); 72 break; 73 } 74 75 cpumask_or(groupmask, groupmask, sched_group_span(group)); 76 77 printk(KERN_CONT " %d:{ span=%*pbl", 78 group->sgc->id, 79 cpumask_pr_args(sched_group_span(group))); 80 81 if ((sd->flags & SD_OVERLAP) && 82 !cpumask_equal(group_balance_mask(group), sched_group_span(group))) { 83 printk(KERN_CONT " mask=%*pbl", 84 cpumask_pr_args(group_balance_mask(group))); 85 } 86 87 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) 88 printk(KERN_CONT " cap=%lu", group->sgc->capacity); 89 90 if (group == sd->groups && sd->child && 91 !cpumask_equal(sched_domain_span(sd->child), 92 sched_group_span(group))) { 93 printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n"); 94 } 95 96 printk(KERN_CONT " }"); 97 98 group = group->next; 99 100 if (group != sd->groups) 101 printk(KERN_CONT ","); 102 103 } while (group != sd->groups); 104 printk(KERN_CONT "\n"); 105 106 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 107 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 108 109 if (sd->parent && 110 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 111 printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n"); 112 return 0; 113 } 114 115 static void sched_domain_debug(struct sched_domain *sd, int cpu) 116 { 117 int level = 0; 118 119 if (!sched_debug_enabled) 120 return; 121 122 if (!sd) { 123 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 124 return; 125 } 126 127 printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu); 128 129 for (;;) { 130 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 131 break; 132 level++; 133 sd = sd->parent; 134 if (!sd) 135 break; 136 } 137 } 138 #else /* !CONFIG_SCHED_DEBUG */ 139 140 # define sched_debug_enabled 0 141 # define sched_domain_debug(sd, cpu) do { } while (0) 142 static inline bool sched_debug(void) 143 { 144 return false; 145 } 146 #endif /* CONFIG_SCHED_DEBUG */ 147 148 static int sd_degenerate(struct sched_domain *sd) 149 { 150 if (cpumask_weight(sched_domain_span(sd)) == 1) 151 return 1; 152 153 /* Following flags need at least 2 groups */ 154 if (sd->flags & (SD_LOAD_BALANCE | 155 SD_BALANCE_NEWIDLE | 156 SD_BALANCE_FORK | 157 SD_BALANCE_EXEC | 158 SD_SHARE_CPUCAPACITY | 159 SD_ASYM_CPUCAPACITY | 160 SD_SHARE_PKG_RESOURCES | 161 SD_SHARE_POWERDOMAIN)) { 162 if (sd->groups != sd->groups->next) 163 return 0; 164 } 165 166 /* Following flags don't use groups */ 167 if (sd->flags & (SD_WAKE_AFFINE)) 168 return 0; 169 170 return 1; 171 } 172 173 static int 174 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 175 { 176 unsigned long cflags = sd->flags, pflags = parent->flags; 177 178 if (sd_degenerate(parent)) 179 return 1; 180 181 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 182 return 0; 183 184 /* Flags needing groups don't count if only 1 group in parent */ 185 if (parent->groups == parent->groups->next) { 186 pflags &= ~(SD_LOAD_BALANCE | 187 SD_BALANCE_NEWIDLE | 188 SD_BALANCE_FORK | 189 SD_BALANCE_EXEC | 190 SD_ASYM_CPUCAPACITY | 191 SD_SHARE_CPUCAPACITY | 192 SD_SHARE_PKG_RESOURCES | 193 SD_PREFER_SIBLING | 194 SD_SHARE_POWERDOMAIN); 195 if (nr_node_ids == 1) 196 pflags &= ~SD_SERIALIZE; 197 } 198 if (~cflags & pflags) 199 return 0; 200 201 return 1; 202 } 203 204 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) 205 DEFINE_STATIC_KEY_FALSE(sched_energy_present); 206 unsigned int sysctl_sched_energy_aware = 1; 207 DEFINE_MUTEX(sched_energy_mutex); 208 bool sched_energy_update; 209 210 #ifdef CONFIG_PROC_SYSCTL 211 int sched_energy_aware_handler(struct ctl_table *table, int write, 212 void __user *buffer, size_t *lenp, loff_t *ppos) 213 { 214 int ret, state; 215 216 if (write && !capable(CAP_SYS_ADMIN)) 217 return -EPERM; 218 219 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 220 if (!ret && write) { 221 state = static_branch_unlikely(&sched_energy_present); 222 if (state != sysctl_sched_energy_aware) { 223 mutex_lock(&sched_energy_mutex); 224 sched_energy_update = 1; 225 rebuild_sched_domains(); 226 sched_energy_update = 0; 227 mutex_unlock(&sched_energy_mutex); 228 } 229 } 230 231 return ret; 232 } 233 #endif 234 235 static void free_pd(struct perf_domain *pd) 236 { 237 struct perf_domain *tmp; 238 239 while (pd) { 240 tmp = pd->next; 241 kfree(pd); 242 pd = tmp; 243 } 244 } 245 246 static struct perf_domain *find_pd(struct perf_domain *pd, int cpu) 247 { 248 while (pd) { 249 if (cpumask_test_cpu(cpu, perf_domain_span(pd))) 250 return pd; 251 pd = pd->next; 252 } 253 254 return NULL; 255 } 256 257 static struct perf_domain *pd_init(int cpu) 258 { 259 struct em_perf_domain *obj = em_cpu_get(cpu); 260 struct perf_domain *pd; 261 262 if (!obj) { 263 if (sched_debug()) 264 pr_info("%s: no EM found for CPU%d\n", __func__, cpu); 265 return NULL; 266 } 267 268 pd = kzalloc(sizeof(*pd), GFP_KERNEL); 269 if (!pd) 270 return NULL; 271 pd->em_pd = obj; 272 273 return pd; 274 } 275 276 static void perf_domain_debug(const struct cpumask *cpu_map, 277 struct perf_domain *pd) 278 { 279 if (!sched_debug() || !pd) 280 return; 281 282 printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map)); 283 284 while (pd) { 285 printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_cstate=%d }", 286 cpumask_first(perf_domain_span(pd)), 287 cpumask_pr_args(perf_domain_span(pd)), 288 em_pd_nr_cap_states(pd->em_pd)); 289 pd = pd->next; 290 } 291 292 printk(KERN_CONT "\n"); 293 } 294 295 static void destroy_perf_domain_rcu(struct rcu_head *rp) 296 { 297 struct perf_domain *pd; 298 299 pd = container_of(rp, struct perf_domain, rcu); 300 free_pd(pd); 301 } 302 303 static void sched_energy_set(bool has_eas) 304 { 305 if (!has_eas && static_branch_unlikely(&sched_energy_present)) { 306 if (sched_debug()) 307 pr_info("%s: stopping EAS\n", __func__); 308 static_branch_disable_cpuslocked(&sched_energy_present); 309 } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) { 310 if (sched_debug()) 311 pr_info("%s: starting EAS\n", __func__); 312 static_branch_enable_cpuslocked(&sched_energy_present); 313 } 314 } 315 316 /* 317 * EAS can be used on a root domain if it meets all the following conditions: 318 * 1. an Energy Model (EM) is available; 319 * 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy. 320 * 3. the EM complexity is low enough to keep scheduling overheads low; 321 * 4. schedutil is driving the frequency of all CPUs of the rd; 322 * 323 * The complexity of the Energy Model is defined as: 324 * 325 * C = nr_pd * (nr_cpus + nr_cs) 326 * 327 * with parameters defined as: 328 * - nr_pd: the number of performance domains 329 * - nr_cpus: the number of CPUs 330 * - nr_cs: the sum of the number of capacity states of all performance 331 * domains (for example, on a system with 2 performance domains, 332 * with 10 capacity states each, nr_cs = 2 * 10 = 20). 333 * 334 * It is generally not a good idea to use such a model in the wake-up path on 335 * very complex platforms because of the associated scheduling overheads. The 336 * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs 337 * with per-CPU DVFS and less than 8 capacity states each, for example. 338 */ 339 #define EM_MAX_COMPLEXITY 2048 340 341 extern struct cpufreq_governor schedutil_gov; 342 static bool build_perf_domains(const struct cpumask *cpu_map) 343 { 344 int i, nr_pd = 0, nr_cs = 0, nr_cpus = cpumask_weight(cpu_map); 345 struct perf_domain *pd = NULL, *tmp; 346 int cpu = cpumask_first(cpu_map); 347 struct root_domain *rd = cpu_rq(cpu)->rd; 348 struct cpufreq_policy *policy; 349 struct cpufreq_governor *gov; 350 351 if (!sysctl_sched_energy_aware) 352 goto free; 353 354 /* EAS is enabled for asymmetric CPU capacity topologies. */ 355 if (!per_cpu(sd_asym_cpucapacity, cpu)) { 356 if (sched_debug()) { 357 pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n", 358 cpumask_pr_args(cpu_map)); 359 } 360 goto free; 361 } 362 363 for_each_cpu(i, cpu_map) { 364 /* Skip already covered CPUs. */ 365 if (find_pd(pd, i)) 366 continue; 367 368 /* Do not attempt EAS if schedutil is not being used. */ 369 policy = cpufreq_cpu_get(i); 370 if (!policy) 371 goto free; 372 gov = policy->governor; 373 cpufreq_cpu_put(policy); 374 if (gov != &schedutil_gov) { 375 if (rd->pd) 376 pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n", 377 cpumask_pr_args(cpu_map)); 378 goto free; 379 } 380 381 /* Create the new pd and add it to the local list. */ 382 tmp = pd_init(i); 383 if (!tmp) 384 goto free; 385 tmp->next = pd; 386 pd = tmp; 387 388 /* 389 * Count performance domains and capacity states for the 390 * complexity check. 391 */ 392 nr_pd++; 393 nr_cs += em_pd_nr_cap_states(pd->em_pd); 394 } 395 396 /* Bail out if the Energy Model complexity is too high. */ 397 if (nr_pd * (nr_cs + nr_cpus) > EM_MAX_COMPLEXITY) { 398 WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n", 399 cpumask_pr_args(cpu_map)); 400 goto free; 401 } 402 403 perf_domain_debug(cpu_map, pd); 404 405 /* Attach the new list of performance domains to the root domain. */ 406 tmp = rd->pd; 407 rcu_assign_pointer(rd->pd, pd); 408 if (tmp) 409 call_rcu(&tmp->rcu, destroy_perf_domain_rcu); 410 411 return !!pd; 412 413 free: 414 free_pd(pd); 415 tmp = rd->pd; 416 rcu_assign_pointer(rd->pd, NULL); 417 if (tmp) 418 call_rcu(&tmp->rcu, destroy_perf_domain_rcu); 419 420 return false; 421 } 422 #else 423 static void free_pd(struct perf_domain *pd) { } 424 #endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/ 425 426 static void free_rootdomain(struct rcu_head *rcu) 427 { 428 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 429 430 cpupri_cleanup(&rd->cpupri); 431 cpudl_cleanup(&rd->cpudl); 432 free_cpumask_var(rd->dlo_mask); 433 free_cpumask_var(rd->rto_mask); 434 free_cpumask_var(rd->online); 435 free_cpumask_var(rd->span); 436 free_pd(rd->pd); 437 kfree(rd); 438 } 439 440 void rq_attach_root(struct rq *rq, struct root_domain *rd) 441 { 442 struct root_domain *old_rd = NULL; 443 unsigned long flags; 444 445 raw_spin_lock_irqsave(&rq->lock, flags); 446 447 if (rq->rd) { 448 old_rd = rq->rd; 449 450 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 451 set_rq_offline(rq); 452 453 cpumask_clear_cpu(rq->cpu, old_rd->span); 454 455 /* 456 * If we dont want to free the old_rd yet then 457 * set old_rd to NULL to skip the freeing later 458 * in this function: 459 */ 460 if (!atomic_dec_and_test(&old_rd->refcount)) 461 old_rd = NULL; 462 } 463 464 atomic_inc(&rd->refcount); 465 rq->rd = rd; 466 467 cpumask_set_cpu(rq->cpu, rd->span); 468 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 469 set_rq_online(rq); 470 471 raw_spin_unlock_irqrestore(&rq->lock, flags); 472 473 if (old_rd) 474 call_rcu(&old_rd->rcu, free_rootdomain); 475 } 476 477 void sched_get_rd(struct root_domain *rd) 478 { 479 atomic_inc(&rd->refcount); 480 } 481 482 void sched_put_rd(struct root_domain *rd) 483 { 484 if (!atomic_dec_and_test(&rd->refcount)) 485 return; 486 487 call_rcu(&rd->rcu, free_rootdomain); 488 } 489 490 static int init_rootdomain(struct root_domain *rd) 491 { 492 if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) 493 goto out; 494 if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) 495 goto free_span; 496 if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 497 goto free_online; 498 if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 499 goto free_dlo_mask; 500 501 #ifdef HAVE_RT_PUSH_IPI 502 rd->rto_cpu = -1; 503 raw_spin_lock_init(&rd->rto_lock); 504 init_irq_work(&rd->rto_push_work, rto_push_irq_work_func); 505 #endif 506 507 init_dl_bw(&rd->dl_bw); 508 if (cpudl_init(&rd->cpudl) != 0) 509 goto free_rto_mask; 510 511 if (cpupri_init(&rd->cpupri) != 0) 512 goto free_cpudl; 513 return 0; 514 515 free_cpudl: 516 cpudl_cleanup(&rd->cpudl); 517 free_rto_mask: 518 free_cpumask_var(rd->rto_mask); 519 free_dlo_mask: 520 free_cpumask_var(rd->dlo_mask); 521 free_online: 522 free_cpumask_var(rd->online); 523 free_span: 524 free_cpumask_var(rd->span); 525 out: 526 return -ENOMEM; 527 } 528 529 /* 530 * By default the system creates a single root-domain with all CPUs as 531 * members (mimicking the global state we have today). 532 */ 533 struct root_domain def_root_domain; 534 535 void init_defrootdomain(void) 536 { 537 init_rootdomain(&def_root_domain); 538 539 atomic_set(&def_root_domain.refcount, 1); 540 } 541 542 static struct root_domain *alloc_rootdomain(void) 543 { 544 struct root_domain *rd; 545 546 rd = kzalloc(sizeof(*rd), GFP_KERNEL); 547 if (!rd) 548 return NULL; 549 550 if (init_rootdomain(rd) != 0) { 551 kfree(rd); 552 return NULL; 553 } 554 555 return rd; 556 } 557 558 static void free_sched_groups(struct sched_group *sg, int free_sgc) 559 { 560 struct sched_group *tmp, *first; 561 562 if (!sg) 563 return; 564 565 first = sg; 566 do { 567 tmp = sg->next; 568 569 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) 570 kfree(sg->sgc); 571 572 if (atomic_dec_and_test(&sg->ref)) 573 kfree(sg); 574 sg = tmp; 575 } while (sg != first); 576 } 577 578 static void destroy_sched_domain(struct sched_domain *sd) 579 { 580 /* 581 * A normal sched domain may have multiple group references, an 582 * overlapping domain, having private groups, only one. Iterate, 583 * dropping group/capacity references, freeing where none remain. 584 */ 585 free_sched_groups(sd->groups, 1); 586 587 if (sd->shared && atomic_dec_and_test(&sd->shared->ref)) 588 kfree(sd->shared); 589 kfree(sd); 590 } 591 592 static void destroy_sched_domains_rcu(struct rcu_head *rcu) 593 { 594 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 595 596 while (sd) { 597 struct sched_domain *parent = sd->parent; 598 destroy_sched_domain(sd); 599 sd = parent; 600 } 601 } 602 603 static void destroy_sched_domains(struct sched_domain *sd) 604 { 605 if (sd) 606 call_rcu(&sd->rcu, destroy_sched_domains_rcu); 607 } 608 609 /* 610 * Keep a special pointer to the highest sched_domain that has 611 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 612 * allows us to avoid some pointer chasing select_idle_sibling(). 613 * 614 * Also keep a unique ID per domain (we use the first CPU number in 615 * the cpumask of the domain), this allows us to quickly tell if 616 * two CPUs are in the same cache domain, see cpus_share_cache(). 617 */ 618 DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc); 619 DEFINE_PER_CPU(int, sd_llc_size); 620 DEFINE_PER_CPU(int, sd_llc_id); 621 DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared); 622 DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa); 623 DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); 624 DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity); 625 DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity); 626 627 static void update_top_cache_domain(int cpu) 628 { 629 struct sched_domain_shared *sds = NULL; 630 struct sched_domain *sd; 631 int id = cpu; 632 int size = 1; 633 634 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 635 if (sd) { 636 id = cpumask_first(sched_domain_span(sd)); 637 size = cpumask_weight(sched_domain_span(sd)); 638 sds = sd->shared; 639 } 640 641 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 642 per_cpu(sd_llc_size, cpu) = size; 643 per_cpu(sd_llc_id, cpu) = id; 644 rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds); 645 646 sd = lowest_flag_domain(cpu, SD_NUMA); 647 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 648 649 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 650 rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd); 651 652 sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY); 653 rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd); 654 } 655 656 /* 657 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 658 * hold the hotplug lock. 659 */ 660 static void 661 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 662 { 663 struct rq *rq = cpu_rq(cpu); 664 struct sched_domain *tmp; 665 666 /* Remove the sched domains which do not contribute to scheduling. */ 667 for (tmp = sd; tmp; ) { 668 struct sched_domain *parent = tmp->parent; 669 if (!parent) 670 break; 671 672 if (sd_parent_degenerate(tmp, parent)) { 673 tmp->parent = parent->parent; 674 if (parent->parent) 675 parent->parent->child = tmp; 676 /* 677 * Transfer SD_PREFER_SIBLING down in case of a 678 * degenerate parent; the spans match for this 679 * so the property transfers. 680 */ 681 if (parent->flags & SD_PREFER_SIBLING) 682 tmp->flags |= SD_PREFER_SIBLING; 683 destroy_sched_domain(parent); 684 } else 685 tmp = tmp->parent; 686 } 687 688 if (sd && sd_degenerate(sd)) { 689 tmp = sd; 690 sd = sd->parent; 691 destroy_sched_domain(tmp); 692 if (sd) 693 sd->child = NULL; 694 } 695 696 sched_domain_debug(sd, cpu); 697 698 rq_attach_root(rq, rd); 699 tmp = rq->sd; 700 rcu_assign_pointer(rq->sd, sd); 701 dirty_sched_domain_sysctl(cpu); 702 destroy_sched_domains(tmp); 703 704 update_top_cache_domain(cpu); 705 } 706 707 struct s_data { 708 struct sched_domain * __percpu *sd; 709 struct root_domain *rd; 710 }; 711 712 enum s_alloc { 713 sa_rootdomain, 714 sa_sd, 715 sa_sd_storage, 716 sa_none, 717 }; 718 719 /* 720 * Return the canonical balance CPU for this group, this is the first CPU 721 * of this group that's also in the balance mask. 722 * 723 * The balance mask are all those CPUs that could actually end up at this 724 * group. See build_balance_mask(). 725 * 726 * Also see should_we_balance(). 727 */ 728 int group_balance_cpu(struct sched_group *sg) 729 { 730 return cpumask_first(group_balance_mask(sg)); 731 } 732 733 734 /* 735 * NUMA topology (first read the regular topology blurb below) 736 * 737 * Given a node-distance table, for example: 738 * 739 * node 0 1 2 3 740 * 0: 10 20 30 20 741 * 1: 20 10 20 30 742 * 2: 30 20 10 20 743 * 3: 20 30 20 10 744 * 745 * which represents a 4 node ring topology like: 746 * 747 * 0 ----- 1 748 * | | 749 * | | 750 * | | 751 * 3 ----- 2 752 * 753 * We want to construct domains and groups to represent this. The way we go 754 * about doing this is to build the domains on 'hops'. For each NUMA level we 755 * construct the mask of all nodes reachable in @level hops. 756 * 757 * For the above NUMA topology that gives 3 levels: 758 * 759 * NUMA-2 0-3 0-3 0-3 0-3 760 * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2} 761 * 762 * NUMA-1 0-1,3 0-2 1-3 0,2-3 763 * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3} 764 * 765 * NUMA-0 0 1 2 3 766 * 767 * 768 * As can be seen; things don't nicely line up as with the regular topology. 769 * When we iterate a domain in child domain chunks some nodes can be 770 * represented multiple times -- hence the "overlap" naming for this part of 771 * the topology. 772 * 773 * In order to minimize this overlap, we only build enough groups to cover the 774 * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3. 775 * 776 * Because: 777 * 778 * - the first group of each domain is its child domain; this 779 * gets us the first 0-1,3 780 * - the only uncovered node is 2, who's child domain is 1-3. 781 * 782 * However, because of the overlap, computing a unique CPU for each group is 783 * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both 784 * groups include the CPUs of Node-0, while those CPUs would not in fact ever 785 * end up at those groups (they would end up in group: 0-1,3). 786 * 787 * To correct this we have to introduce the group balance mask. This mask 788 * will contain those CPUs in the group that can reach this group given the 789 * (child) domain tree. 790 * 791 * With this we can once again compute balance_cpu and sched_group_capacity 792 * relations. 793 * 794 * XXX include words on how balance_cpu is unique and therefore can be 795 * used for sched_group_capacity links. 796 * 797 * 798 * Another 'interesting' topology is: 799 * 800 * node 0 1 2 3 801 * 0: 10 20 20 30 802 * 1: 20 10 20 20 803 * 2: 20 20 10 20 804 * 3: 30 20 20 10 805 * 806 * Which looks a little like: 807 * 808 * 0 ----- 1 809 * | / | 810 * | / | 811 * | / | 812 * 2 ----- 3 813 * 814 * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3 815 * are not. 816 * 817 * This leads to a few particularly weird cases where the sched_domain's are 818 * not of the same number for each CPU. Consider: 819 * 820 * NUMA-2 0-3 0-3 821 * groups: {0-2},{1-3} {1-3},{0-2} 822 * 823 * NUMA-1 0-2 0-3 0-3 1-3 824 * 825 * NUMA-0 0 1 2 3 826 * 827 */ 828 829 830 /* 831 * Build the balance mask; it contains only those CPUs that can arrive at this 832 * group and should be considered to continue balancing. 833 * 834 * We do this during the group creation pass, therefore the group information 835 * isn't complete yet, however since each group represents a (child) domain we 836 * can fully construct this using the sched_domain bits (which are already 837 * complete). 838 */ 839 static void 840 build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask) 841 { 842 const struct cpumask *sg_span = sched_group_span(sg); 843 struct sd_data *sdd = sd->private; 844 struct sched_domain *sibling; 845 int i; 846 847 cpumask_clear(mask); 848 849 for_each_cpu(i, sg_span) { 850 sibling = *per_cpu_ptr(sdd->sd, i); 851 852 /* 853 * Can happen in the asymmetric case, where these siblings are 854 * unused. The mask will not be empty because those CPUs that 855 * do have the top domain _should_ span the domain. 856 */ 857 if (!sibling->child) 858 continue; 859 860 /* If we would not end up here, we can't continue from here */ 861 if (!cpumask_equal(sg_span, sched_domain_span(sibling->child))) 862 continue; 863 864 cpumask_set_cpu(i, mask); 865 } 866 867 /* We must not have empty masks here */ 868 WARN_ON_ONCE(cpumask_empty(mask)); 869 } 870 871 /* 872 * XXX: This creates per-node group entries; since the load-balancer will 873 * immediately access remote memory to construct this group's load-balance 874 * statistics having the groups node local is of dubious benefit. 875 */ 876 static struct sched_group * 877 build_group_from_child_sched_domain(struct sched_domain *sd, int cpu) 878 { 879 struct sched_group *sg; 880 struct cpumask *sg_span; 881 882 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 883 GFP_KERNEL, cpu_to_node(cpu)); 884 885 if (!sg) 886 return NULL; 887 888 sg_span = sched_group_span(sg); 889 if (sd->child) 890 cpumask_copy(sg_span, sched_domain_span(sd->child)); 891 else 892 cpumask_copy(sg_span, sched_domain_span(sd)); 893 894 atomic_inc(&sg->ref); 895 return sg; 896 } 897 898 static void init_overlap_sched_group(struct sched_domain *sd, 899 struct sched_group *sg) 900 { 901 struct cpumask *mask = sched_domains_tmpmask2; 902 struct sd_data *sdd = sd->private; 903 struct cpumask *sg_span; 904 int cpu; 905 906 build_balance_mask(sd, sg, mask); 907 cpu = cpumask_first_and(sched_group_span(sg), mask); 908 909 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); 910 if (atomic_inc_return(&sg->sgc->ref) == 1) 911 cpumask_copy(group_balance_mask(sg), mask); 912 else 913 WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask)); 914 915 /* 916 * Initialize sgc->capacity such that even if we mess up the 917 * domains and no possible iteration will get us here, we won't 918 * die on a /0 trap. 919 */ 920 sg_span = sched_group_span(sg); 921 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); 922 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; 923 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; 924 } 925 926 static int 927 build_overlap_sched_groups(struct sched_domain *sd, int cpu) 928 { 929 struct sched_group *first = NULL, *last = NULL, *sg; 930 const struct cpumask *span = sched_domain_span(sd); 931 struct cpumask *covered = sched_domains_tmpmask; 932 struct sd_data *sdd = sd->private; 933 struct sched_domain *sibling; 934 int i; 935 936 cpumask_clear(covered); 937 938 for_each_cpu_wrap(i, span, cpu) { 939 struct cpumask *sg_span; 940 941 if (cpumask_test_cpu(i, covered)) 942 continue; 943 944 sibling = *per_cpu_ptr(sdd->sd, i); 945 946 /* 947 * Asymmetric node setups can result in situations where the 948 * domain tree is of unequal depth, make sure to skip domains 949 * that already cover the entire range. 950 * 951 * In that case build_sched_domains() will have terminated the 952 * iteration early and our sibling sd spans will be empty. 953 * Domains should always include the CPU they're built on, so 954 * check that. 955 */ 956 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 957 continue; 958 959 sg = build_group_from_child_sched_domain(sibling, cpu); 960 if (!sg) 961 goto fail; 962 963 sg_span = sched_group_span(sg); 964 cpumask_or(covered, covered, sg_span); 965 966 init_overlap_sched_group(sd, sg); 967 968 if (!first) 969 first = sg; 970 if (last) 971 last->next = sg; 972 last = sg; 973 last->next = first; 974 } 975 sd->groups = first; 976 977 return 0; 978 979 fail: 980 free_sched_groups(first, 0); 981 982 return -ENOMEM; 983 } 984 985 986 /* 987 * Package topology (also see the load-balance blurb in fair.c) 988 * 989 * The scheduler builds a tree structure to represent a number of important 990 * topology features. By default (default_topology[]) these include: 991 * 992 * - Simultaneous multithreading (SMT) 993 * - Multi-Core Cache (MC) 994 * - Package (DIE) 995 * 996 * Where the last one more or less denotes everything up to a NUMA node. 997 * 998 * The tree consists of 3 primary data structures: 999 * 1000 * sched_domain -> sched_group -> sched_group_capacity 1001 * ^ ^ ^ ^ 1002 * `-' `-' 1003 * 1004 * The sched_domains are per-CPU and have a two way link (parent & child) and 1005 * denote the ever growing mask of CPUs belonging to that level of topology. 1006 * 1007 * Each sched_domain has a circular (double) linked list of sched_group's, each 1008 * denoting the domains of the level below (or individual CPUs in case of the 1009 * first domain level). The sched_group linked by a sched_domain includes the 1010 * CPU of that sched_domain [*]. 1011 * 1012 * Take for instance a 2 threaded, 2 core, 2 cache cluster part: 1013 * 1014 * CPU 0 1 2 3 4 5 6 7 1015 * 1016 * DIE [ ] 1017 * MC [ ] [ ] 1018 * SMT [ ] [ ] [ ] [ ] 1019 * 1020 * - or - 1021 * 1022 * DIE 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7 1023 * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7 1024 * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7 1025 * 1026 * CPU 0 1 2 3 4 5 6 7 1027 * 1028 * One way to think about it is: sched_domain moves you up and down among these 1029 * topology levels, while sched_group moves you sideways through it, at child 1030 * domain granularity. 1031 * 1032 * sched_group_capacity ensures each unique sched_group has shared storage. 1033 * 1034 * There are two related construction problems, both require a CPU that 1035 * uniquely identify each group (for a given domain): 1036 * 1037 * - The first is the balance_cpu (see should_we_balance() and the 1038 * load-balance blub in fair.c); for each group we only want 1 CPU to 1039 * continue balancing at a higher domain. 1040 * 1041 * - The second is the sched_group_capacity; we want all identical groups 1042 * to share a single sched_group_capacity. 1043 * 1044 * Since these topologies are exclusive by construction. That is, its 1045 * impossible for an SMT thread to belong to multiple cores, and cores to 1046 * be part of multiple caches. There is a very clear and unique location 1047 * for each CPU in the hierarchy. 1048 * 1049 * Therefore computing a unique CPU for each group is trivial (the iteration 1050 * mask is redundant and set all 1s; all CPUs in a group will end up at _that_ 1051 * group), we can simply pick the first CPU in each group. 1052 * 1053 * 1054 * [*] in other words, the first group of each domain is its child domain. 1055 */ 1056 1057 static struct sched_group *get_group(int cpu, struct sd_data *sdd) 1058 { 1059 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 1060 struct sched_domain *child = sd->child; 1061 struct sched_group *sg; 1062 bool already_visited; 1063 1064 if (child) 1065 cpu = cpumask_first(sched_domain_span(child)); 1066 1067 sg = *per_cpu_ptr(sdd->sg, cpu); 1068 sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); 1069 1070 /* Increase refcounts for claim_allocations: */ 1071 already_visited = atomic_inc_return(&sg->ref) > 1; 1072 /* sgc visits should follow a similar trend as sg */ 1073 WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1)); 1074 1075 /* If we have already visited that group, it's already initialized. */ 1076 if (already_visited) 1077 return sg; 1078 1079 if (child) { 1080 cpumask_copy(sched_group_span(sg), sched_domain_span(child)); 1081 cpumask_copy(group_balance_mask(sg), sched_group_span(sg)); 1082 } else { 1083 cpumask_set_cpu(cpu, sched_group_span(sg)); 1084 cpumask_set_cpu(cpu, group_balance_mask(sg)); 1085 } 1086 1087 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg)); 1088 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; 1089 sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; 1090 1091 return sg; 1092 } 1093 1094 /* 1095 * build_sched_groups will build a circular linked list of the groups 1096 * covered by the given span, will set each group's ->cpumask correctly, 1097 * and will initialize their ->sgc. 1098 * 1099 * Assumes the sched_domain tree is fully constructed 1100 */ 1101 static int 1102 build_sched_groups(struct sched_domain *sd, int cpu) 1103 { 1104 struct sched_group *first = NULL, *last = NULL; 1105 struct sd_data *sdd = sd->private; 1106 const struct cpumask *span = sched_domain_span(sd); 1107 struct cpumask *covered; 1108 int i; 1109 1110 lockdep_assert_held(&sched_domains_mutex); 1111 covered = sched_domains_tmpmask; 1112 1113 cpumask_clear(covered); 1114 1115 for_each_cpu_wrap(i, span, cpu) { 1116 struct sched_group *sg; 1117 1118 if (cpumask_test_cpu(i, covered)) 1119 continue; 1120 1121 sg = get_group(i, sdd); 1122 1123 cpumask_or(covered, covered, sched_group_span(sg)); 1124 1125 if (!first) 1126 first = sg; 1127 if (last) 1128 last->next = sg; 1129 last = sg; 1130 } 1131 last->next = first; 1132 sd->groups = first; 1133 1134 return 0; 1135 } 1136 1137 /* 1138 * Initialize sched groups cpu_capacity. 1139 * 1140 * cpu_capacity indicates the capacity of sched group, which is used while 1141 * distributing the load between different sched groups in a sched domain. 1142 * Typically cpu_capacity for all the groups in a sched domain will be same 1143 * unless there are asymmetries in the topology. If there are asymmetries, 1144 * group having more cpu_capacity will pickup more load compared to the 1145 * group having less cpu_capacity. 1146 */ 1147 static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) 1148 { 1149 struct sched_group *sg = sd->groups; 1150 1151 WARN_ON(!sg); 1152 1153 do { 1154 int cpu, max_cpu = -1; 1155 1156 sg->group_weight = cpumask_weight(sched_group_span(sg)); 1157 1158 if (!(sd->flags & SD_ASYM_PACKING)) 1159 goto next; 1160 1161 for_each_cpu(cpu, sched_group_span(sg)) { 1162 if (max_cpu < 0) 1163 max_cpu = cpu; 1164 else if (sched_asym_prefer(cpu, max_cpu)) 1165 max_cpu = cpu; 1166 } 1167 sg->asym_prefer_cpu = max_cpu; 1168 1169 next: 1170 sg = sg->next; 1171 } while (sg != sd->groups); 1172 1173 if (cpu != group_balance_cpu(sg)) 1174 return; 1175 1176 update_group_capacity(sd, cpu); 1177 } 1178 1179 /* 1180 * Initializers for schedule domains 1181 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 1182 */ 1183 1184 static int default_relax_domain_level = -1; 1185 int sched_domain_level_max; 1186 1187 static int __init setup_relax_domain_level(char *str) 1188 { 1189 if (kstrtoint(str, 0, &default_relax_domain_level)) 1190 pr_warn("Unable to set relax_domain_level\n"); 1191 1192 return 1; 1193 } 1194 __setup("relax_domain_level=", setup_relax_domain_level); 1195 1196 static void set_domain_attribute(struct sched_domain *sd, 1197 struct sched_domain_attr *attr) 1198 { 1199 int request; 1200 1201 if (!attr || attr->relax_domain_level < 0) { 1202 if (default_relax_domain_level < 0) 1203 return; 1204 else 1205 request = default_relax_domain_level; 1206 } else 1207 request = attr->relax_domain_level; 1208 if (request < sd->level) { 1209 /* Turn off idle balance on this domain: */ 1210 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 1211 } else { 1212 /* Turn on idle balance on this domain: */ 1213 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 1214 } 1215 } 1216 1217 static void __sdt_free(const struct cpumask *cpu_map); 1218 static int __sdt_alloc(const struct cpumask *cpu_map); 1219 1220 static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 1221 const struct cpumask *cpu_map) 1222 { 1223 switch (what) { 1224 case sa_rootdomain: 1225 if (!atomic_read(&d->rd->refcount)) 1226 free_rootdomain(&d->rd->rcu); 1227 /* Fall through */ 1228 case sa_sd: 1229 free_percpu(d->sd); 1230 /* Fall through */ 1231 case sa_sd_storage: 1232 __sdt_free(cpu_map); 1233 /* Fall through */ 1234 case sa_none: 1235 break; 1236 } 1237 } 1238 1239 static enum s_alloc 1240 __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) 1241 { 1242 memset(d, 0, sizeof(*d)); 1243 1244 if (__sdt_alloc(cpu_map)) 1245 return sa_sd_storage; 1246 d->sd = alloc_percpu(struct sched_domain *); 1247 if (!d->sd) 1248 return sa_sd_storage; 1249 d->rd = alloc_rootdomain(); 1250 if (!d->rd) 1251 return sa_sd; 1252 1253 return sa_rootdomain; 1254 } 1255 1256 /* 1257 * NULL the sd_data elements we've used to build the sched_domain and 1258 * sched_group structure so that the subsequent __free_domain_allocs() 1259 * will not free the data we're using. 1260 */ 1261 static void claim_allocations(int cpu, struct sched_domain *sd) 1262 { 1263 struct sd_data *sdd = sd->private; 1264 1265 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 1266 *per_cpu_ptr(sdd->sd, cpu) = NULL; 1267 1268 if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref)) 1269 *per_cpu_ptr(sdd->sds, cpu) = NULL; 1270 1271 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 1272 *per_cpu_ptr(sdd->sg, cpu) = NULL; 1273 1274 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) 1275 *per_cpu_ptr(sdd->sgc, cpu) = NULL; 1276 } 1277 1278 #ifdef CONFIG_NUMA 1279 enum numa_topology_type sched_numa_topology_type; 1280 1281 static int sched_domains_numa_levels; 1282 static int sched_domains_curr_level; 1283 1284 int sched_max_numa_distance; 1285 static int *sched_domains_numa_distance; 1286 static struct cpumask ***sched_domains_numa_masks; 1287 #endif 1288 1289 /* 1290 * SD_flags allowed in topology descriptions. 1291 * 1292 * These flags are purely descriptive of the topology and do not prescribe 1293 * behaviour. Behaviour is artificial and mapped in the below sd_init() 1294 * function: 1295 * 1296 * SD_SHARE_CPUCAPACITY - describes SMT topologies 1297 * SD_SHARE_PKG_RESOURCES - describes shared caches 1298 * SD_NUMA - describes NUMA topologies 1299 * SD_SHARE_POWERDOMAIN - describes shared power domain 1300 * 1301 * Odd one out, which beside describing the topology has a quirk also 1302 * prescribes the desired behaviour that goes along with it: 1303 * 1304 * SD_ASYM_PACKING - describes SMT quirks 1305 */ 1306 #define TOPOLOGY_SD_FLAGS \ 1307 (SD_SHARE_CPUCAPACITY | \ 1308 SD_SHARE_PKG_RESOURCES | \ 1309 SD_NUMA | \ 1310 SD_ASYM_PACKING | \ 1311 SD_SHARE_POWERDOMAIN) 1312 1313 static struct sched_domain * 1314 sd_init(struct sched_domain_topology_level *tl, 1315 const struct cpumask *cpu_map, 1316 struct sched_domain *child, int dflags, int cpu) 1317 { 1318 struct sd_data *sdd = &tl->data; 1319 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 1320 int sd_id, sd_weight, sd_flags = 0; 1321 1322 #ifdef CONFIG_NUMA 1323 /* 1324 * Ugly hack to pass state to sd_numa_mask()... 1325 */ 1326 sched_domains_curr_level = tl->numa_level; 1327 #endif 1328 1329 sd_weight = cpumask_weight(tl->mask(cpu)); 1330 1331 if (tl->sd_flags) 1332 sd_flags = (*tl->sd_flags)(); 1333 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, 1334 "wrong sd_flags in topology description\n")) 1335 sd_flags &= ~TOPOLOGY_SD_FLAGS; 1336 1337 /* Apply detected topology flags */ 1338 sd_flags |= dflags; 1339 1340 *sd = (struct sched_domain){ 1341 .min_interval = sd_weight, 1342 .max_interval = 2*sd_weight, 1343 .busy_factor = 32, 1344 .imbalance_pct = 125, 1345 1346 .cache_nice_tries = 0, 1347 .busy_idx = 0, 1348 .idle_idx = 0, 1349 .newidle_idx = 0, 1350 .wake_idx = 0, 1351 .forkexec_idx = 0, 1352 1353 .flags = 1*SD_LOAD_BALANCE 1354 | 1*SD_BALANCE_NEWIDLE 1355 | 1*SD_BALANCE_EXEC 1356 | 1*SD_BALANCE_FORK 1357 | 0*SD_BALANCE_WAKE 1358 | 1*SD_WAKE_AFFINE 1359 | 0*SD_SHARE_CPUCAPACITY 1360 | 0*SD_SHARE_PKG_RESOURCES 1361 | 0*SD_SERIALIZE 1362 | 1*SD_PREFER_SIBLING 1363 | 0*SD_NUMA 1364 | sd_flags 1365 , 1366 1367 .last_balance = jiffies, 1368 .balance_interval = sd_weight, 1369 .max_newidle_lb_cost = 0, 1370 .next_decay_max_lb_cost = jiffies, 1371 .child = child, 1372 #ifdef CONFIG_SCHED_DEBUG 1373 .name = tl->name, 1374 #endif 1375 }; 1376 1377 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 1378 sd_id = cpumask_first(sched_domain_span(sd)); 1379 1380 /* 1381 * Convert topological properties into behaviour. 1382 */ 1383 1384 if (sd->flags & SD_ASYM_CPUCAPACITY) { 1385 struct sched_domain *t = sd; 1386 1387 /* 1388 * Don't attempt to spread across CPUs of different capacities. 1389 */ 1390 if (sd->child) 1391 sd->child->flags &= ~SD_PREFER_SIBLING; 1392 1393 for_each_lower_domain(t) 1394 t->flags |= SD_BALANCE_WAKE; 1395 } 1396 1397 if (sd->flags & SD_SHARE_CPUCAPACITY) { 1398 sd->imbalance_pct = 110; 1399 1400 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { 1401 sd->imbalance_pct = 117; 1402 sd->cache_nice_tries = 1; 1403 sd->busy_idx = 2; 1404 1405 #ifdef CONFIG_NUMA 1406 } else if (sd->flags & SD_NUMA) { 1407 sd->cache_nice_tries = 2; 1408 sd->busy_idx = 3; 1409 sd->idle_idx = 2; 1410 1411 sd->flags &= ~SD_PREFER_SIBLING; 1412 sd->flags |= SD_SERIALIZE; 1413 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { 1414 sd->flags &= ~(SD_BALANCE_EXEC | 1415 SD_BALANCE_FORK | 1416 SD_WAKE_AFFINE); 1417 } 1418 1419 #endif 1420 } else { 1421 sd->cache_nice_tries = 1; 1422 sd->busy_idx = 2; 1423 sd->idle_idx = 1; 1424 } 1425 1426 /* 1427 * For all levels sharing cache; connect a sched_domain_shared 1428 * instance. 1429 */ 1430 if (sd->flags & SD_SHARE_PKG_RESOURCES) { 1431 sd->shared = *per_cpu_ptr(sdd->sds, sd_id); 1432 atomic_inc(&sd->shared->ref); 1433 atomic_set(&sd->shared->nr_busy_cpus, sd_weight); 1434 } 1435 1436 sd->private = sdd; 1437 1438 return sd; 1439 } 1440 1441 /* 1442 * Topology list, bottom-up. 1443 */ 1444 static struct sched_domain_topology_level default_topology[] = { 1445 #ifdef CONFIG_SCHED_SMT 1446 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, 1447 #endif 1448 #ifdef CONFIG_SCHED_MC 1449 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, 1450 #endif 1451 { cpu_cpu_mask, SD_INIT_NAME(DIE) }, 1452 { NULL, }, 1453 }; 1454 1455 static struct sched_domain_topology_level *sched_domain_topology = 1456 default_topology; 1457 1458 #define for_each_sd_topology(tl) \ 1459 for (tl = sched_domain_topology; tl->mask; tl++) 1460 1461 void set_sched_topology(struct sched_domain_topology_level *tl) 1462 { 1463 if (WARN_ON_ONCE(sched_smp_initialized)) 1464 return; 1465 1466 sched_domain_topology = tl; 1467 } 1468 1469 #ifdef CONFIG_NUMA 1470 1471 static const struct cpumask *sd_numa_mask(int cpu) 1472 { 1473 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 1474 } 1475 1476 static void sched_numa_warn(const char *str) 1477 { 1478 static int done = false; 1479 int i,j; 1480 1481 if (done) 1482 return; 1483 1484 done = true; 1485 1486 printk(KERN_WARNING "ERROR: %s\n\n", str); 1487 1488 for (i = 0; i < nr_node_ids; i++) { 1489 printk(KERN_WARNING " "); 1490 for (j = 0; j < nr_node_ids; j++) 1491 printk(KERN_CONT "%02d ", node_distance(i,j)); 1492 printk(KERN_CONT "\n"); 1493 } 1494 printk(KERN_WARNING "\n"); 1495 } 1496 1497 bool find_numa_distance(int distance) 1498 { 1499 int i; 1500 1501 if (distance == node_distance(0, 0)) 1502 return true; 1503 1504 for (i = 0; i < sched_domains_numa_levels; i++) { 1505 if (sched_domains_numa_distance[i] == distance) 1506 return true; 1507 } 1508 1509 return false; 1510 } 1511 1512 /* 1513 * A system can have three types of NUMA topology: 1514 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system 1515 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes 1516 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane 1517 * 1518 * The difference between a glueless mesh topology and a backplane 1519 * topology lies in whether communication between not directly 1520 * connected nodes goes through intermediary nodes (where programs 1521 * could run), or through backplane controllers. This affects 1522 * placement of programs. 1523 * 1524 * The type of topology can be discerned with the following tests: 1525 * - If the maximum distance between any nodes is 1 hop, the system 1526 * is directly connected. 1527 * - If for two nodes A and B, located N > 1 hops away from each other, 1528 * there is an intermediary node C, which is < N hops away from both 1529 * nodes A and B, the system is a glueless mesh. 1530 */ 1531 static void init_numa_topology_type(void) 1532 { 1533 int a, b, c, n; 1534 1535 n = sched_max_numa_distance; 1536 1537 if (sched_domains_numa_levels <= 2) { 1538 sched_numa_topology_type = NUMA_DIRECT; 1539 return; 1540 } 1541 1542 for_each_online_node(a) { 1543 for_each_online_node(b) { 1544 /* Find two nodes furthest removed from each other. */ 1545 if (node_distance(a, b) < n) 1546 continue; 1547 1548 /* Is there an intermediary node between a and b? */ 1549 for_each_online_node(c) { 1550 if (node_distance(a, c) < n && 1551 node_distance(b, c) < n) { 1552 sched_numa_topology_type = 1553 NUMA_GLUELESS_MESH; 1554 return; 1555 } 1556 } 1557 1558 sched_numa_topology_type = NUMA_BACKPLANE; 1559 return; 1560 } 1561 } 1562 } 1563 1564 void sched_init_numa(void) 1565 { 1566 int next_distance, curr_distance = node_distance(0, 0); 1567 struct sched_domain_topology_level *tl; 1568 int level = 0; 1569 int i, j, k; 1570 1571 sched_domains_numa_distance = kzalloc(sizeof(int) * (nr_node_ids + 1), GFP_KERNEL); 1572 if (!sched_domains_numa_distance) 1573 return; 1574 1575 /* Includes NUMA identity node at level 0. */ 1576 sched_domains_numa_distance[level++] = curr_distance; 1577 sched_domains_numa_levels = level; 1578 1579 /* 1580 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 1581 * unique distances in the node_distance() table. 1582 * 1583 * Assumes node_distance(0,j) includes all distances in 1584 * node_distance(i,j) in order to avoid cubic time. 1585 */ 1586 next_distance = curr_distance; 1587 for (i = 0; i < nr_node_ids; i++) { 1588 for (j = 0; j < nr_node_ids; j++) { 1589 for (k = 0; k < nr_node_ids; k++) { 1590 int distance = node_distance(i, k); 1591 1592 if (distance > curr_distance && 1593 (distance < next_distance || 1594 next_distance == curr_distance)) 1595 next_distance = distance; 1596 1597 /* 1598 * While not a strong assumption it would be nice to know 1599 * about cases where if node A is connected to B, B is not 1600 * equally connected to A. 1601 */ 1602 if (sched_debug() && node_distance(k, i) != distance) 1603 sched_numa_warn("Node-distance not symmetric"); 1604 1605 if (sched_debug() && i && !find_numa_distance(distance)) 1606 sched_numa_warn("Node-0 not representative"); 1607 } 1608 if (next_distance != curr_distance) { 1609 sched_domains_numa_distance[level++] = next_distance; 1610 sched_domains_numa_levels = level; 1611 curr_distance = next_distance; 1612 } else break; 1613 } 1614 1615 /* 1616 * In case of sched_debug() we verify the above assumption. 1617 */ 1618 if (!sched_debug()) 1619 break; 1620 } 1621 1622 /* 1623 * 'level' contains the number of unique distances 1624 * 1625 * The sched_domains_numa_distance[] array includes the actual distance 1626 * numbers. 1627 */ 1628 1629 /* 1630 * Here, we should temporarily reset sched_domains_numa_levels to 0. 1631 * If it fails to allocate memory for array sched_domains_numa_masks[][], 1632 * the array will contain less then 'level' members. This could be 1633 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 1634 * in other functions. 1635 * 1636 * We reset it to 'level' at the end of this function. 1637 */ 1638 sched_domains_numa_levels = 0; 1639 1640 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 1641 if (!sched_domains_numa_masks) 1642 return; 1643 1644 /* 1645 * Now for each level, construct a mask per node which contains all 1646 * CPUs of nodes that are that many hops away from us. 1647 */ 1648 for (i = 0; i < level; i++) { 1649 sched_domains_numa_masks[i] = 1650 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 1651 if (!sched_domains_numa_masks[i]) 1652 return; 1653 1654 for (j = 0; j < nr_node_ids; j++) { 1655 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 1656 if (!mask) 1657 return; 1658 1659 sched_domains_numa_masks[i][j] = mask; 1660 1661 for_each_node(k) { 1662 if (node_distance(j, k) > sched_domains_numa_distance[i]) 1663 continue; 1664 1665 cpumask_or(mask, mask, cpumask_of_node(k)); 1666 } 1667 } 1668 } 1669 1670 /* Compute default topology size */ 1671 for (i = 0; sched_domain_topology[i].mask; i++); 1672 1673 tl = kzalloc((i + level + 1) * 1674 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 1675 if (!tl) 1676 return; 1677 1678 /* 1679 * Copy the default topology bits.. 1680 */ 1681 for (i = 0; sched_domain_topology[i].mask; i++) 1682 tl[i] = sched_domain_topology[i]; 1683 1684 /* 1685 * Add the NUMA identity distance, aka single NODE. 1686 */ 1687 tl[i++] = (struct sched_domain_topology_level){ 1688 .mask = sd_numa_mask, 1689 .numa_level = 0, 1690 SD_INIT_NAME(NODE) 1691 }; 1692 1693 /* 1694 * .. and append 'j' levels of NUMA goodness. 1695 */ 1696 for (j = 1; j < level; i++, j++) { 1697 tl[i] = (struct sched_domain_topology_level){ 1698 .mask = sd_numa_mask, 1699 .sd_flags = cpu_numa_flags, 1700 .flags = SDTL_OVERLAP, 1701 .numa_level = j, 1702 SD_INIT_NAME(NUMA) 1703 }; 1704 } 1705 1706 sched_domain_topology = tl; 1707 1708 sched_domains_numa_levels = level; 1709 sched_max_numa_distance = sched_domains_numa_distance[level - 1]; 1710 1711 init_numa_topology_type(); 1712 } 1713 1714 void sched_domains_numa_masks_set(unsigned int cpu) 1715 { 1716 int node = cpu_to_node(cpu); 1717 int i, j; 1718 1719 for (i = 0; i < sched_domains_numa_levels; i++) { 1720 for (j = 0; j < nr_node_ids; j++) { 1721 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 1722 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 1723 } 1724 } 1725 } 1726 1727 void sched_domains_numa_masks_clear(unsigned int cpu) 1728 { 1729 int i, j; 1730 1731 for (i = 0; i < sched_domains_numa_levels; i++) { 1732 for (j = 0; j < nr_node_ids; j++) 1733 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 1734 } 1735 } 1736 1737 #endif /* CONFIG_NUMA */ 1738 1739 static int __sdt_alloc(const struct cpumask *cpu_map) 1740 { 1741 struct sched_domain_topology_level *tl; 1742 int j; 1743 1744 for_each_sd_topology(tl) { 1745 struct sd_data *sdd = &tl->data; 1746 1747 sdd->sd = alloc_percpu(struct sched_domain *); 1748 if (!sdd->sd) 1749 return -ENOMEM; 1750 1751 sdd->sds = alloc_percpu(struct sched_domain_shared *); 1752 if (!sdd->sds) 1753 return -ENOMEM; 1754 1755 sdd->sg = alloc_percpu(struct sched_group *); 1756 if (!sdd->sg) 1757 return -ENOMEM; 1758 1759 sdd->sgc = alloc_percpu(struct sched_group_capacity *); 1760 if (!sdd->sgc) 1761 return -ENOMEM; 1762 1763 for_each_cpu(j, cpu_map) { 1764 struct sched_domain *sd; 1765 struct sched_domain_shared *sds; 1766 struct sched_group *sg; 1767 struct sched_group_capacity *sgc; 1768 1769 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 1770 GFP_KERNEL, cpu_to_node(j)); 1771 if (!sd) 1772 return -ENOMEM; 1773 1774 *per_cpu_ptr(sdd->sd, j) = sd; 1775 1776 sds = kzalloc_node(sizeof(struct sched_domain_shared), 1777 GFP_KERNEL, cpu_to_node(j)); 1778 if (!sds) 1779 return -ENOMEM; 1780 1781 *per_cpu_ptr(sdd->sds, j) = sds; 1782 1783 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 1784 GFP_KERNEL, cpu_to_node(j)); 1785 if (!sg) 1786 return -ENOMEM; 1787 1788 sg->next = sg; 1789 1790 *per_cpu_ptr(sdd->sg, j) = sg; 1791 1792 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), 1793 GFP_KERNEL, cpu_to_node(j)); 1794 if (!sgc) 1795 return -ENOMEM; 1796 1797 #ifdef CONFIG_SCHED_DEBUG 1798 sgc->id = j; 1799 #endif 1800 1801 *per_cpu_ptr(sdd->sgc, j) = sgc; 1802 } 1803 } 1804 1805 return 0; 1806 } 1807 1808 static void __sdt_free(const struct cpumask *cpu_map) 1809 { 1810 struct sched_domain_topology_level *tl; 1811 int j; 1812 1813 for_each_sd_topology(tl) { 1814 struct sd_data *sdd = &tl->data; 1815 1816 for_each_cpu(j, cpu_map) { 1817 struct sched_domain *sd; 1818 1819 if (sdd->sd) { 1820 sd = *per_cpu_ptr(sdd->sd, j); 1821 if (sd && (sd->flags & SD_OVERLAP)) 1822 free_sched_groups(sd->groups, 0); 1823 kfree(*per_cpu_ptr(sdd->sd, j)); 1824 } 1825 1826 if (sdd->sds) 1827 kfree(*per_cpu_ptr(sdd->sds, j)); 1828 if (sdd->sg) 1829 kfree(*per_cpu_ptr(sdd->sg, j)); 1830 if (sdd->sgc) 1831 kfree(*per_cpu_ptr(sdd->sgc, j)); 1832 } 1833 free_percpu(sdd->sd); 1834 sdd->sd = NULL; 1835 free_percpu(sdd->sds); 1836 sdd->sds = NULL; 1837 free_percpu(sdd->sg); 1838 sdd->sg = NULL; 1839 free_percpu(sdd->sgc); 1840 sdd->sgc = NULL; 1841 } 1842 } 1843 1844 static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 1845 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 1846 struct sched_domain *child, int dflags, int cpu) 1847 { 1848 struct sched_domain *sd = sd_init(tl, cpu_map, child, dflags, cpu); 1849 1850 if (child) { 1851 sd->level = child->level + 1; 1852 sched_domain_level_max = max(sched_domain_level_max, sd->level); 1853 child->parent = sd; 1854 1855 if (!cpumask_subset(sched_domain_span(child), 1856 sched_domain_span(sd))) { 1857 pr_err("BUG: arch topology borken\n"); 1858 #ifdef CONFIG_SCHED_DEBUG 1859 pr_err(" the %s domain not a subset of the %s domain\n", 1860 child->name, sd->name); 1861 #endif 1862 /* Fixup, ensure @sd has at least @child CPUs. */ 1863 cpumask_or(sched_domain_span(sd), 1864 sched_domain_span(sd), 1865 sched_domain_span(child)); 1866 } 1867 1868 } 1869 set_domain_attribute(sd, attr); 1870 1871 return sd; 1872 } 1873 1874 /* 1875 * Find the sched_domain_topology_level where all CPU capacities are visible 1876 * for all CPUs. 1877 */ 1878 static struct sched_domain_topology_level 1879 *asym_cpu_capacity_level(const struct cpumask *cpu_map) 1880 { 1881 int i, j, asym_level = 0; 1882 bool asym = false; 1883 struct sched_domain_topology_level *tl, *asym_tl = NULL; 1884 unsigned long cap; 1885 1886 /* Is there any asymmetry? */ 1887 cap = arch_scale_cpu_capacity(NULL, cpumask_first(cpu_map)); 1888 1889 for_each_cpu(i, cpu_map) { 1890 if (arch_scale_cpu_capacity(NULL, i) != cap) { 1891 asym = true; 1892 break; 1893 } 1894 } 1895 1896 if (!asym) 1897 return NULL; 1898 1899 /* 1900 * Examine topology from all CPU's point of views to detect the lowest 1901 * sched_domain_topology_level where a highest capacity CPU is visible 1902 * to everyone. 1903 */ 1904 for_each_cpu(i, cpu_map) { 1905 unsigned long max_capacity = arch_scale_cpu_capacity(NULL, i); 1906 int tl_id = 0; 1907 1908 for_each_sd_topology(tl) { 1909 if (tl_id < asym_level) 1910 goto next_level; 1911 1912 for_each_cpu_and(j, tl->mask(i), cpu_map) { 1913 unsigned long capacity; 1914 1915 capacity = arch_scale_cpu_capacity(NULL, j); 1916 1917 if (capacity <= max_capacity) 1918 continue; 1919 1920 max_capacity = capacity; 1921 asym_level = tl_id; 1922 asym_tl = tl; 1923 } 1924 next_level: 1925 tl_id++; 1926 } 1927 } 1928 1929 return asym_tl; 1930 } 1931 1932 1933 /* 1934 * Build sched domains for a given set of CPUs and attach the sched domains 1935 * to the individual CPUs 1936 */ 1937 static int 1938 build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr) 1939 { 1940 enum s_alloc alloc_state; 1941 struct sched_domain *sd; 1942 struct s_data d; 1943 struct rq *rq = NULL; 1944 int i, ret = -ENOMEM; 1945 struct sched_domain_topology_level *tl_asym; 1946 bool has_asym = false; 1947 1948 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 1949 if (alloc_state != sa_rootdomain) 1950 goto error; 1951 1952 tl_asym = asym_cpu_capacity_level(cpu_map); 1953 1954 /* Set up domains for CPUs specified by the cpu_map: */ 1955 for_each_cpu(i, cpu_map) { 1956 struct sched_domain_topology_level *tl; 1957 1958 sd = NULL; 1959 for_each_sd_topology(tl) { 1960 int dflags = 0; 1961 1962 if (tl == tl_asym) { 1963 dflags |= SD_ASYM_CPUCAPACITY; 1964 has_asym = true; 1965 } 1966 1967 sd = build_sched_domain(tl, cpu_map, attr, sd, dflags, i); 1968 1969 if (tl == sched_domain_topology) 1970 *per_cpu_ptr(d.sd, i) = sd; 1971 if (tl->flags & SDTL_OVERLAP) 1972 sd->flags |= SD_OVERLAP; 1973 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 1974 break; 1975 } 1976 } 1977 1978 /* Build the groups for the domains */ 1979 for_each_cpu(i, cpu_map) { 1980 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 1981 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 1982 if (sd->flags & SD_OVERLAP) { 1983 if (build_overlap_sched_groups(sd, i)) 1984 goto error; 1985 } else { 1986 if (build_sched_groups(sd, i)) 1987 goto error; 1988 } 1989 } 1990 } 1991 1992 /* Calculate CPU capacity for physical packages and nodes */ 1993 for (i = nr_cpumask_bits-1; i >= 0; i--) { 1994 if (!cpumask_test_cpu(i, cpu_map)) 1995 continue; 1996 1997 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 1998 claim_allocations(i, sd); 1999 init_sched_groups_capacity(i, sd); 2000 } 2001 } 2002 2003 /* Attach the domains */ 2004 rcu_read_lock(); 2005 for_each_cpu(i, cpu_map) { 2006 rq = cpu_rq(i); 2007 sd = *per_cpu_ptr(d.sd, i); 2008 2009 /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */ 2010 if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity)) 2011 WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig); 2012 2013 cpu_attach_domain(sd, d.rd, i); 2014 } 2015 rcu_read_unlock(); 2016 2017 if (has_asym) 2018 static_branch_enable_cpuslocked(&sched_asym_cpucapacity); 2019 2020 if (rq && sched_debug_enabled) { 2021 pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", 2022 cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); 2023 } 2024 2025 ret = 0; 2026 error: 2027 __free_domain_allocs(&d, alloc_state, cpu_map); 2028 2029 return ret; 2030 } 2031 2032 /* Current sched domains: */ 2033 static cpumask_var_t *doms_cur; 2034 2035 /* Number of sched domains in 'doms_cur': */ 2036 static int ndoms_cur; 2037 2038 /* Attribues of custom domains in 'doms_cur' */ 2039 static struct sched_domain_attr *dattr_cur; 2040 2041 /* 2042 * Special case: If a kmalloc() of a doms_cur partition (array of 2043 * cpumask) fails, then fallback to a single sched domain, 2044 * as determined by the single cpumask fallback_doms. 2045 */ 2046 static cpumask_var_t fallback_doms; 2047 2048 /* 2049 * arch_update_cpu_topology lets virtualized architectures update the 2050 * CPU core maps. It is supposed to return 1 if the topology changed 2051 * or 0 if it stayed the same. 2052 */ 2053 int __weak arch_update_cpu_topology(void) 2054 { 2055 return 0; 2056 } 2057 2058 cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 2059 { 2060 int i; 2061 cpumask_var_t *doms; 2062 2063 doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL); 2064 if (!doms) 2065 return NULL; 2066 for (i = 0; i < ndoms; i++) { 2067 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 2068 free_sched_domains(doms, i); 2069 return NULL; 2070 } 2071 } 2072 return doms; 2073 } 2074 2075 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 2076 { 2077 unsigned int i; 2078 for (i = 0; i < ndoms; i++) 2079 free_cpumask_var(doms[i]); 2080 kfree(doms); 2081 } 2082 2083 /* 2084 * Set up scheduler domains and groups. For now this just excludes isolated 2085 * CPUs, but could be used to exclude other special cases in the future. 2086 */ 2087 int sched_init_domains(const struct cpumask *cpu_map) 2088 { 2089 int err; 2090 2091 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL); 2092 zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL); 2093 zalloc_cpumask_var(&fallback_doms, GFP_KERNEL); 2094 2095 arch_update_cpu_topology(); 2096 ndoms_cur = 1; 2097 doms_cur = alloc_sched_domains(ndoms_cur); 2098 if (!doms_cur) 2099 doms_cur = &fallback_doms; 2100 cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN)); 2101 err = build_sched_domains(doms_cur[0], NULL); 2102 register_sched_domain_sysctl(); 2103 2104 return err; 2105 } 2106 2107 /* 2108 * Detach sched domains from a group of CPUs specified in cpu_map 2109 * These CPUs will now be attached to the NULL domain 2110 */ 2111 static void detach_destroy_domains(const struct cpumask *cpu_map) 2112 { 2113 int i; 2114 2115 rcu_read_lock(); 2116 for_each_cpu(i, cpu_map) 2117 cpu_attach_domain(NULL, &def_root_domain, i); 2118 rcu_read_unlock(); 2119 } 2120 2121 /* handle null as "default" */ 2122 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 2123 struct sched_domain_attr *new, int idx_new) 2124 { 2125 struct sched_domain_attr tmp; 2126 2127 /* Fast path: */ 2128 if (!new && !cur) 2129 return 1; 2130 2131 tmp = SD_ATTR_INIT; 2132 2133 return !memcmp(cur ? (cur + idx_cur) : &tmp, 2134 new ? (new + idx_new) : &tmp, 2135 sizeof(struct sched_domain_attr)); 2136 } 2137 2138 /* 2139 * Partition sched domains as specified by the 'ndoms_new' 2140 * cpumasks in the array doms_new[] of cpumasks. This compares 2141 * doms_new[] to the current sched domain partitioning, doms_cur[]. 2142 * It destroys each deleted domain and builds each new domain. 2143 * 2144 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 2145 * The masks don't intersect (don't overlap.) We should setup one 2146 * sched domain for each mask. CPUs not in any of the cpumasks will 2147 * not be load balanced. If the same cpumask appears both in the 2148 * current 'doms_cur' domains and in the new 'doms_new', we can leave 2149 * it as it is. 2150 * 2151 * The passed in 'doms_new' should be allocated using 2152 * alloc_sched_domains. This routine takes ownership of it and will 2153 * free_sched_domains it when done with it. If the caller failed the 2154 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 2155 * and partition_sched_domains() will fallback to the single partition 2156 * 'fallback_doms', it also forces the domains to be rebuilt. 2157 * 2158 * If doms_new == NULL it will be replaced with cpu_online_mask. 2159 * ndoms_new == 0 is a special case for destroying existing domains, 2160 * and it will not create the default domain. 2161 * 2162 * Call with hotplug lock held 2163 */ 2164 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 2165 struct sched_domain_attr *dattr_new) 2166 { 2167 bool __maybe_unused has_eas = false; 2168 int i, j, n; 2169 int new_topology; 2170 2171 mutex_lock(&sched_domains_mutex); 2172 2173 /* Always unregister in case we don't destroy any domains: */ 2174 unregister_sched_domain_sysctl(); 2175 2176 /* Let the architecture update CPU core mappings: */ 2177 new_topology = arch_update_cpu_topology(); 2178 2179 if (!doms_new) { 2180 WARN_ON_ONCE(dattr_new); 2181 n = 0; 2182 doms_new = alloc_sched_domains(1); 2183 if (doms_new) { 2184 n = 1; 2185 cpumask_and(doms_new[0], cpu_active_mask, 2186 housekeeping_cpumask(HK_FLAG_DOMAIN)); 2187 } 2188 } else { 2189 n = ndoms_new; 2190 } 2191 2192 /* Destroy deleted domains: */ 2193 for (i = 0; i < ndoms_cur; i++) { 2194 for (j = 0; j < n && !new_topology; j++) { 2195 if (cpumask_equal(doms_cur[i], doms_new[j]) && 2196 dattrs_equal(dattr_cur, i, dattr_new, j)) 2197 goto match1; 2198 } 2199 /* No match - a current sched domain not in new doms_new[] */ 2200 detach_destroy_domains(doms_cur[i]); 2201 match1: 2202 ; 2203 } 2204 2205 n = ndoms_cur; 2206 if (!doms_new) { 2207 n = 0; 2208 doms_new = &fallback_doms; 2209 cpumask_and(doms_new[0], cpu_active_mask, 2210 housekeeping_cpumask(HK_FLAG_DOMAIN)); 2211 } 2212 2213 /* Build new domains: */ 2214 for (i = 0; i < ndoms_new; i++) { 2215 for (j = 0; j < n && !new_topology; j++) { 2216 if (cpumask_equal(doms_new[i], doms_cur[j]) && 2217 dattrs_equal(dattr_new, i, dattr_cur, j)) 2218 goto match2; 2219 } 2220 /* No match - add a new doms_new */ 2221 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 2222 match2: 2223 ; 2224 } 2225 2226 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) 2227 /* Build perf. domains: */ 2228 for (i = 0; i < ndoms_new; i++) { 2229 for (j = 0; j < n && !sched_energy_update; j++) { 2230 if (cpumask_equal(doms_new[i], doms_cur[j]) && 2231 cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) { 2232 has_eas = true; 2233 goto match3; 2234 } 2235 } 2236 /* No match - add perf. domains for a new rd */ 2237 has_eas |= build_perf_domains(doms_new[i]); 2238 match3: 2239 ; 2240 } 2241 sched_energy_set(has_eas); 2242 #endif 2243 2244 /* Remember the new sched domains: */ 2245 if (doms_cur != &fallback_doms) 2246 free_sched_domains(doms_cur, ndoms_cur); 2247 2248 kfree(dattr_cur); 2249 doms_cur = doms_new; 2250 dattr_cur = dattr_new; 2251 ndoms_cur = ndoms_new; 2252 2253 register_sched_domain_sysctl(); 2254 2255 mutex_unlock(&sched_domains_mutex); 2256 } 2257