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-rw-r--r--kernel/sched/topology.c1658
1 files changed, 1658 insertions, 0 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
new file mode 100644
index 000000000000..1b0b4fb12837
--- /dev/null
+++ b/kernel/sched/topology.c
@@ -0,0 +1,1658 @@
1/*
2 * Scheduler topology setup/handling methods
3 */
4#include <linux/sched.h>
5#include <linux/mutex.h>
6
7#include "sched.h"
8
9DEFINE_MUTEX(sched_domains_mutex);
10
11/* Protected by sched_domains_mutex: */
12cpumask_var_t sched_domains_tmpmask;
13
14#ifdef CONFIG_SCHED_DEBUG
15
16static __read_mostly int sched_debug_enabled;
17
18static int __init sched_debug_setup(char *str)
19{
20 sched_debug_enabled = 1;
21
22 return 0;
23}
24early_param("sched_debug", sched_debug_setup);
25
26static inline bool sched_debug(void)
27{
28 return sched_debug_enabled;
29}
30
31static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
32 struct cpumask *groupmask)
33{
34 struct sched_group *group = sd->groups;
35
36 cpumask_clear(groupmask);
37
38 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
39
40 if (!(sd->flags & SD_LOAD_BALANCE)) {
41 printk("does not load-balance\n");
42 if (sd->parent)
43 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
44 " has parent");
45 return -1;
46 }
47
48 printk(KERN_CONT "span %*pbl level %s\n",
49 cpumask_pr_args(sched_domain_span(sd)), sd->name);
50
51 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
52 printk(KERN_ERR "ERROR: domain->span does not contain "
53 "CPU%d\n", cpu);
54 }
55 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
56 printk(KERN_ERR "ERROR: domain->groups does not contain"
57 " CPU%d\n", cpu);
58 }
59
60 printk(KERN_DEBUG "%*s groups:", level + 1, "");
61 do {
62 if (!group) {
63 printk("\n");
64 printk(KERN_ERR "ERROR: group is NULL\n");
65 break;
66 }
67
68 if (!cpumask_weight(sched_group_cpus(group))) {
69 printk(KERN_CONT "\n");
70 printk(KERN_ERR "ERROR: empty group\n");
71 break;
72 }
73
74 if (!(sd->flags & SD_OVERLAP) &&
75 cpumask_intersects(groupmask, sched_group_cpus(group))) {
76 printk(KERN_CONT "\n");
77 printk(KERN_ERR "ERROR: repeated CPUs\n");
78 break;
79 }
80
81 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
82
83 printk(KERN_CONT " %*pbl",
84 cpumask_pr_args(sched_group_cpus(group)));
85 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) {
86 printk(KERN_CONT " (cpu_capacity = %lu)",
87 group->sgc->capacity);
88 }
89
90 group = group->next;
91 } while (group != sd->groups);
92 printk(KERN_CONT "\n");
93
94 if (!cpumask_equal(sched_domain_span(sd), groupmask))
95 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
96
97 if (sd->parent &&
98 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
99 printk(KERN_ERR "ERROR: parent span is not a superset "
100 "of domain->span\n");
101 return 0;
102}
103
104static void sched_domain_debug(struct sched_domain *sd, int cpu)
105{
106 int level = 0;
107
108 if (!sched_debug_enabled)
109 return;
110
111 if (!sd) {
112 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
113 return;
114 }
115
116 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
117
118 for (;;) {
119 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
120 break;
121 level++;
122 sd = sd->parent;
123 if (!sd)
124 break;
125 }
126}
127#else /* !CONFIG_SCHED_DEBUG */
128
129# define sched_debug_enabled 0
130# define sched_domain_debug(sd, cpu) do { } while (0)
131static inline bool sched_debug(void)
132{
133 return false;
134}
135#endif /* CONFIG_SCHED_DEBUG */
136
137static int sd_degenerate(struct sched_domain *sd)
138{
139 if (cpumask_weight(sched_domain_span(sd)) == 1)
140 return 1;
141
142 /* Following flags need at least 2 groups */
143 if (sd->flags & (SD_LOAD_BALANCE |
144 SD_BALANCE_NEWIDLE |
145 SD_BALANCE_FORK |
146 SD_BALANCE_EXEC |
147 SD_SHARE_CPUCAPACITY |
148 SD_ASYM_CPUCAPACITY |
149 SD_SHARE_PKG_RESOURCES |
150 SD_SHARE_POWERDOMAIN)) {
151 if (sd->groups != sd->groups->next)
152 return 0;
153 }
154
155 /* Following flags don't use groups */
156 if (sd->flags & (SD_WAKE_AFFINE))
157 return 0;
158
159 return 1;
160}
161
162static int
163sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
164{
165 unsigned long cflags = sd->flags, pflags = parent->flags;
166
167 if (sd_degenerate(parent))
168 return 1;
169
170 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
171 return 0;
172
173 /* Flags needing groups don't count if only 1 group in parent */
174 if (parent->groups == parent->groups->next) {
175 pflags &= ~(SD_LOAD_BALANCE |
176 SD_BALANCE_NEWIDLE |
177 SD_BALANCE_FORK |
178 SD_BALANCE_EXEC |
179 SD_ASYM_CPUCAPACITY |
180 SD_SHARE_CPUCAPACITY |
181 SD_SHARE_PKG_RESOURCES |
182 SD_PREFER_SIBLING |
183 SD_SHARE_POWERDOMAIN);
184 if (nr_node_ids == 1)
185 pflags &= ~SD_SERIALIZE;
186 }
187 if (~cflags & pflags)
188 return 0;
189
190 return 1;
191}
192
193static void free_rootdomain(struct rcu_head *rcu)
194{
195 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
196
197 cpupri_cleanup(&rd->cpupri);
198 cpudl_cleanup(&rd->cpudl);
199 free_cpumask_var(rd->dlo_mask);
200 free_cpumask_var(rd->rto_mask);
201 free_cpumask_var(rd->online);
202 free_cpumask_var(rd->span);
203 kfree(rd);
204}
205
206void rq_attach_root(struct rq *rq, struct root_domain *rd)
207{
208 struct root_domain *old_rd = NULL;
209 unsigned long flags;
210
211 raw_spin_lock_irqsave(&rq->lock, flags);
212
213 if (rq->rd) {
214 old_rd = rq->rd;
215
216 if (cpumask_test_cpu(rq->cpu, old_rd->online))
217 set_rq_offline(rq);
218
219 cpumask_clear_cpu(rq->cpu, old_rd->span);
220
221 /*
222 * If we dont want to free the old_rd yet then
223 * set old_rd to NULL to skip the freeing later
224 * in this function:
225 */
226 if (!atomic_dec_and_test(&old_rd->refcount))
227 old_rd = NULL;
228 }
229
230 atomic_inc(&rd->refcount);
231 rq->rd = rd;
232
233 cpumask_set_cpu(rq->cpu, rd->span);
234 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
235 set_rq_online(rq);
236
237 raw_spin_unlock_irqrestore(&rq->lock, flags);
238
239 if (old_rd)
240 call_rcu_sched(&old_rd->rcu, free_rootdomain);
241}
242
243static int init_rootdomain(struct root_domain *rd)
244{
245 memset(rd, 0, sizeof(*rd));
246
247 if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
248 goto out;
249 if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
250 goto free_span;
251 if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
252 goto free_online;
253 if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
254 goto free_dlo_mask;
255
256 init_dl_bw(&rd->dl_bw);
257 if (cpudl_init(&rd->cpudl) != 0)
258 goto free_rto_mask;
259
260 if (cpupri_init(&rd->cpupri) != 0)
261 goto free_cpudl;
262 return 0;
263
264free_cpudl:
265 cpudl_cleanup(&rd->cpudl);
266free_rto_mask:
267 free_cpumask_var(rd->rto_mask);
268free_dlo_mask:
269 free_cpumask_var(rd->dlo_mask);
270free_online:
271 free_cpumask_var(rd->online);
272free_span:
273 free_cpumask_var(rd->span);
274out:
275 return -ENOMEM;
276}
277
278/*
279 * By default the system creates a single root-domain with all CPUs as
280 * members (mimicking the global state we have today).
281 */
282struct root_domain def_root_domain;
283
284void init_defrootdomain(void)
285{
286 init_rootdomain(&def_root_domain);
287
288 atomic_set(&def_root_domain.refcount, 1);
289}
290
291static struct root_domain *alloc_rootdomain(void)
292{
293 struct root_domain *rd;
294
295 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
296 if (!rd)
297 return NULL;
298
299 if (init_rootdomain(rd) != 0) {
300 kfree(rd);
301 return NULL;
302 }
303
304 return rd;
305}
306
307static void free_sched_groups(struct sched_group *sg, int free_sgc)
308{
309 struct sched_group *tmp, *first;
310
311 if (!sg)
312 return;
313
314 first = sg;
315 do {
316 tmp = sg->next;
317
318 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
319 kfree(sg->sgc);
320
321 kfree(sg);
322 sg = tmp;
323 } while (sg != first);
324}
325
326static void destroy_sched_domain(struct sched_domain *sd)
327{
328 /*
329 * If its an overlapping domain it has private groups, iterate and
330 * nuke them all.
331 */
332 if (sd->flags & SD_OVERLAP) {
333 free_sched_groups(sd->groups, 1);
334 } else if (atomic_dec_and_test(&sd->groups->ref)) {
335 kfree(sd->groups->sgc);
336 kfree(sd->groups);
337 }
338 if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
339 kfree(sd->shared);
340 kfree(sd);
341}
342
343static void destroy_sched_domains_rcu(struct rcu_head *rcu)
344{
345 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
346
347 while (sd) {
348 struct sched_domain *parent = sd->parent;
349 destroy_sched_domain(sd);
350 sd = parent;
351 }
352}
353
354static void destroy_sched_domains(struct sched_domain *sd)
355{
356 if (sd)
357 call_rcu(&sd->rcu, destroy_sched_domains_rcu);
358}
359
360/*
361 * Keep a special pointer to the highest sched_domain that has
362 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
363 * allows us to avoid some pointer chasing select_idle_sibling().
364 *
365 * Also keep a unique ID per domain (we use the first CPU number in
366 * the cpumask of the domain), this allows us to quickly tell if
367 * two CPUs are in the same cache domain, see cpus_share_cache().
368 */
369DEFINE_PER_CPU(struct sched_domain *, sd_llc);
370DEFINE_PER_CPU(int, sd_llc_size);
371DEFINE_PER_CPU(int, sd_llc_id);
372DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
373DEFINE_PER_CPU(struct sched_domain *, sd_numa);
374DEFINE_PER_CPU(struct sched_domain *, sd_asym);
375
376static void update_top_cache_domain(int cpu)
377{
378 struct sched_domain_shared *sds = NULL;
379 struct sched_domain *sd;
380 int id = cpu;
381 int size = 1;
382
383 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
384 if (sd) {
385 id = cpumask_first(sched_domain_span(sd));
386 size = cpumask_weight(sched_domain_span(sd));
387 sds = sd->shared;
388 }
389
390 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
391 per_cpu(sd_llc_size, cpu) = size;
392 per_cpu(sd_llc_id, cpu) = id;
393 rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
394
395 sd = lowest_flag_domain(cpu, SD_NUMA);
396 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
397
398 sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
399 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd);
400}
401
402/*
403 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
404 * hold the hotplug lock.
405 */
406static void
407cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
408{
409 struct rq *rq = cpu_rq(cpu);
410 struct sched_domain *tmp;
411
412 /* Remove the sched domains which do not contribute to scheduling. */
413 for (tmp = sd; tmp; ) {
414 struct sched_domain *parent = tmp->parent;
415 if (!parent)
416 break;
417
418 if (sd_parent_degenerate(tmp, parent)) {
419 tmp->parent = parent->parent;
420 if (parent->parent)
421 parent->parent->child = tmp;
422 /*
423 * Transfer SD_PREFER_SIBLING down in case of a
424 * degenerate parent; the spans match for this
425 * so the property transfers.
426 */
427 if (parent->flags & SD_PREFER_SIBLING)
428 tmp->flags |= SD_PREFER_SIBLING;
429 destroy_sched_domain(parent);
430 } else
431 tmp = tmp->parent;
432 }
433
434 if (sd && sd_degenerate(sd)) {
435 tmp = sd;
436 sd = sd->parent;
437 destroy_sched_domain(tmp);
438 if (sd)
439 sd->child = NULL;
440 }
441
442 sched_domain_debug(sd, cpu);
443
444 rq_attach_root(rq, rd);
445 tmp = rq->sd;
446 rcu_assign_pointer(rq->sd, sd);
447 destroy_sched_domains(tmp);
448
449 update_top_cache_domain(cpu);
450}
451
452/* Setup the mask of CPUs configured for isolated domains */
453static int __init isolated_cpu_setup(char *str)
454{
455 int ret;
456
457 alloc_bootmem_cpumask_var(&cpu_isolated_map);
458 ret = cpulist_parse(str, cpu_isolated_map);
459 if (ret) {
460 pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids);
461 return 0;
462 }
463 return 1;
464}
465__setup("isolcpus=", isolated_cpu_setup);
466
467struct s_data {
468 struct sched_domain ** __percpu sd;
469 struct root_domain *rd;
470};
471
472enum s_alloc {
473 sa_rootdomain,
474 sa_sd,
475 sa_sd_storage,
476 sa_none,
477};
478
479/*
480 * Build an iteration mask that can exclude certain CPUs from the upwards
481 * domain traversal.
482 *
483 * Asymmetric node setups can result in situations where the domain tree is of
484 * unequal depth, make sure to skip domains that already cover the entire
485 * range.
486 *
487 * In that case build_sched_domains() will have terminated the iteration early
488 * and our sibling sd spans will be empty. Domains should always include the
489 * CPU they're built on, so check that.
490 */
491static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
492{
493 const struct cpumask *span = sched_domain_span(sd);
494 struct sd_data *sdd = sd->private;
495 struct sched_domain *sibling;
496 int i;
497
498 for_each_cpu(i, span) {
499 sibling = *per_cpu_ptr(sdd->sd, i);
500 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
501 continue;
502
503 cpumask_set_cpu(i, sched_group_mask(sg));
504 }
505}
506
507/*
508 * Return the canonical balance CPU for this group, this is the first CPU
509 * of this group that's also in the iteration mask.
510 */
511int group_balance_cpu(struct sched_group *sg)
512{
513 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
514}
515
516static int
517build_overlap_sched_groups(struct sched_domain *sd, int cpu)
518{
519 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
520 const struct cpumask *span = sched_domain_span(sd);
521 struct cpumask *covered = sched_domains_tmpmask;
522 struct sd_data *sdd = sd->private;
523 struct sched_domain *sibling;
524 int i;
525
526 cpumask_clear(covered);
527
528 for_each_cpu(i, span) {
529 struct cpumask *sg_span;
530
531 if (cpumask_test_cpu(i, covered))
532 continue;
533
534 sibling = *per_cpu_ptr(sdd->sd, i);
535
536 /* See the comment near build_group_mask(). */
537 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
538 continue;
539
540 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
541 GFP_KERNEL, cpu_to_node(cpu));
542
543 if (!sg)
544 goto fail;
545
546 sg_span = sched_group_cpus(sg);
547 if (sibling->child)
548 cpumask_copy(sg_span, sched_domain_span(sibling->child));
549 else
550 cpumask_set_cpu(i, sg_span);
551
552 cpumask_or(covered, covered, sg_span);
553
554 sg->sgc = *per_cpu_ptr(sdd->sgc, i);
555 if (atomic_inc_return(&sg->sgc->ref) == 1)
556 build_group_mask(sd, sg);
557
558 /*
559 * Initialize sgc->capacity such that even if we mess up the
560 * domains and no possible iteration will get us here, we won't
561 * die on a /0 trap.
562 */
563 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
564 sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
565
566 /*
567 * Make sure the first group of this domain contains the
568 * canonical balance CPU. Otherwise the sched_domain iteration
569 * breaks. See update_sg_lb_stats().
570 */
571 if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
572 group_balance_cpu(sg) == cpu)
573 groups = sg;
574
575 if (!first)
576 first = sg;
577 if (last)
578 last->next = sg;
579 last = sg;
580 last->next = first;
581 }
582 sd->groups = groups;
583
584 return 0;
585
586fail:
587 free_sched_groups(first, 0);
588
589 return -ENOMEM;
590}
591
592static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
593{
594 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
595 struct sched_domain *child = sd->child;
596
597 if (child)
598 cpu = cpumask_first(sched_domain_span(child));
599
600 if (sg) {
601 *sg = *per_cpu_ptr(sdd->sg, cpu);
602 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu);
603
604 /* For claim_allocations: */
605 atomic_set(&(*sg)->sgc->ref, 1);
606 }
607
608 return cpu;
609}
610
611/*
612 * build_sched_groups will build a circular linked list of the groups
613 * covered by the given span, and will set each group's ->cpumask correctly,
614 * and ->cpu_capacity to 0.
615 *
616 * Assumes the sched_domain tree is fully constructed
617 */
618static int
619build_sched_groups(struct sched_domain *sd, int cpu)
620{
621 struct sched_group *first = NULL, *last = NULL;
622 struct sd_data *sdd = sd->private;
623 const struct cpumask *span = sched_domain_span(sd);
624 struct cpumask *covered;
625 int i;
626
627 get_group(cpu, sdd, &sd->groups);
628 atomic_inc(&sd->groups->ref);
629
630 if (cpu != cpumask_first(span))
631 return 0;
632
633 lockdep_assert_held(&sched_domains_mutex);
634 covered = sched_domains_tmpmask;
635
636 cpumask_clear(covered);
637
638 for_each_cpu(i, span) {
639 struct sched_group *sg;
640 int group, j;
641
642 if (cpumask_test_cpu(i, covered))
643 continue;
644
645 group = get_group(i, sdd, &sg);
646 cpumask_setall(sched_group_mask(sg));
647
648 for_each_cpu(j, span) {
649 if (get_group(j, sdd, NULL) != group)
650 continue;
651
652 cpumask_set_cpu(j, covered);
653 cpumask_set_cpu(j, sched_group_cpus(sg));
654 }
655
656 if (!first)
657 first = sg;
658 if (last)
659 last->next = sg;
660 last = sg;
661 }
662 last->next = first;
663
664 return 0;
665}
666
667/*
668 * Initialize sched groups cpu_capacity.
669 *
670 * cpu_capacity indicates the capacity of sched group, which is used while
671 * distributing the load between different sched groups in a sched domain.
672 * Typically cpu_capacity for all the groups in a sched domain will be same
673 * unless there are asymmetries in the topology. If there are asymmetries,
674 * group having more cpu_capacity will pickup more load compared to the
675 * group having less cpu_capacity.
676 */
677static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
678{
679 struct sched_group *sg = sd->groups;
680
681 WARN_ON(!sg);
682
683 do {
684 int cpu, max_cpu = -1;
685
686 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
687
688 if (!(sd->flags & SD_ASYM_PACKING))
689 goto next;
690
691 for_each_cpu(cpu, sched_group_cpus(sg)) {
692 if (max_cpu < 0)
693 max_cpu = cpu;
694 else if (sched_asym_prefer(cpu, max_cpu))
695 max_cpu = cpu;
696 }
697 sg->asym_prefer_cpu = max_cpu;
698
699next:
700 sg = sg->next;
701 } while (sg != sd->groups);
702
703 if (cpu != group_balance_cpu(sg))
704 return;
705
706 update_group_capacity(sd, cpu);
707}
708
709/*
710 * Initializers for schedule domains
711 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
712 */
713
714static int default_relax_domain_level = -1;
715int sched_domain_level_max;
716
717static int __init setup_relax_domain_level(char *str)
718{
719 if (kstrtoint(str, 0, &default_relax_domain_level))
720 pr_warn("Unable to set relax_domain_level\n");
721
722 return 1;
723}
724__setup("relax_domain_level=", setup_relax_domain_level);
725
726static void set_domain_attribute(struct sched_domain *sd,
727 struct sched_domain_attr *attr)
728{
729 int request;
730
731 if (!attr || attr->relax_domain_level < 0) {
732 if (default_relax_domain_level < 0)
733 return;
734 else
735 request = default_relax_domain_level;
736 } else
737 request = attr->relax_domain_level;
738 if (request < sd->level) {
739 /* Turn off idle balance on this domain: */
740 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
741 } else {
742 /* Turn on idle balance on this domain: */
743 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
744 }
745}
746
747static void __sdt_free(const struct cpumask *cpu_map);
748static int __sdt_alloc(const struct cpumask *cpu_map);
749
750static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
751 const struct cpumask *cpu_map)
752{
753 switch (what) {
754 case sa_rootdomain:
755 if (!atomic_read(&d->rd->refcount))
756 free_rootdomain(&d->rd->rcu);
757 /* Fall through */
758 case sa_sd:
759 free_percpu(d->sd);
760 /* Fall through */
761 case sa_sd_storage:
762 __sdt_free(cpu_map);
763 /* Fall through */
764 case sa_none:
765 break;
766 }
767}
768
769static enum s_alloc
770__visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map)
771{
772 memset(d, 0, sizeof(*d));
773
774 if (__sdt_alloc(cpu_map))
775 return sa_sd_storage;
776 d->sd = alloc_percpu(struct sched_domain *);
777 if (!d->sd)
778 return sa_sd_storage;
779 d->rd = alloc_rootdomain();
780 if (!d->rd)
781 return sa_sd;
782 return sa_rootdomain;
783}
784
785/*
786 * NULL the sd_data elements we've used to build the sched_domain and
787 * sched_group structure so that the subsequent __free_domain_allocs()
788 * will not free the data we're using.
789 */
790static void claim_allocations(int cpu, struct sched_domain *sd)
791{
792 struct sd_data *sdd = sd->private;
793
794 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
795 *per_cpu_ptr(sdd->sd, cpu) = NULL;
796
797 if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
798 *per_cpu_ptr(sdd->sds, cpu) = NULL;
799
800 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
801 *per_cpu_ptr(sdd->sg, cpu) = NULL;
802
803 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
804 *per_cpu_ptr(sdd->sgc, cpu) = NULL;
805}
806
807#ifdef CONFIG_NUMA
808static int sched_domains_numa_levels;
809enum numa_topology_type sched_numa_topology_type;
810static int *sched_domains_numa_distance;
811int sched_max_numa_distance;
812static struct cpumask ***sched_domains_numa_masks;
813static int sched_domains_curr_level;
814#endif
815
816/*
817 * SD_flags allowed in topology descriptions.
818 *
819 * These flags are purely descriptive of the topology and do not prescribe
820 * behaviour. Behaviour is artificial and mapped in the below sd_init()
821 * function:
822 *
823 * SD_SHARE_CPUCAPACITY - describes SMT topologies
824 * SD_SHARE_PKG_RESOURCES - describes shared caches
825 * SD_NUMA - describes NUMA topologies
826 * SD_SHARE_POWERDOMAIN - describes shared power domain
827 * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies
828 *
829 * Odd one out, which beside describing the topology has a quirk also
830 * prescribes the desired behaviour that goes along with it:
831 *
832 * SD_ASYM_PACKING - describes SMT quirks
833 */
834#define TOPOLOGY_SD_FLAGS \
835 (SD_SHARE_CPUCAPACITY | \
836 SD_SHARE_PKG_RESOURCES | \
837 SD_NUMA | \
838 SD_ASYM_PACKING | \
839 SD_ASYM_CPUCAPACITY | \
840 SD_SHARE_POWERDOMAIN)
841
842static struct sched_domain *
843sd_init(struct sched_domain_topology_level *tl,
844 const struct cpumask *cpu_map,
845 struct sched_domain *child, int cpu)
846{
847 struct sd_data *sdd = &tl->data;
848 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
849 int sd_id, sd_weight, sd_flags = 0;
850
851#ifdef CONFIG_NUMA
852 /*
853 * Ugly hack to pass state to sd_numa_mask()...
854 */
855 sched_domains_curr_level = tl->numa_level;
856#endif
857
858 sd_weight = cpumask_weight(tl->mask(cpu));
859
860 if (tl->sd_flags)
861 sd_flags = (*tl->sd_flags)();
862 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
863 "wrong sd_flags in topology description\n"))
864 sd_flags &= ~TOPOLOGY_SD_FLAGS;
865
866 *sd = (struct sched_domain){
867 .min_interval = sd_weight,
868 .max_interval = 2*sd_weight,
869 .busy_factor = 32,
870 .imbalance_pct = 125,
871
872 .cache_nice_tries = 0,
873 .busy_idx = 0,
874 .idle_idx = 0,
875 .newidle_idx = 0,
876 .wake_idx = 0,
877 .forkexec_idx = 0,
878
879 .flags = 1*SD_LOAD_BALANCE
880 | 1*SD_BALANCE_NEWIDLE
881 | 1*SD_BALANCE_EXEC
882 | 1*SD_BALANCE_FORK
883 | 0*SD_BALANCE_WAKE
884 | 1*SD_WAKE_AFFINE
885 | 0*SD_SHARE_CPUCAPACITY
886 | 0*SD_SHARE_PKG_RESOURCES
887 | 0*SD_SERIALIZE
888 | 0*SD_PREFER_SIBLING
889 | 0*SD_NUMA
890 | sd_flags
891 ,
892
893 .last_balance = jiffies,
894 .balance_interval = sd_weight,
895 .smt_gain = 0,
896 .max_newidle_lb_cost = 0,
897 .next_decay_max_lb_cost = jiffies,
898 .child = child,
899#ifdef CONFIG_SCHED_DEBUG
900 .name = tl->name,
901#endif
902 };
903
904 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
905 sd_id = cpumask_first(sched_domain_span(sd));
906
907 /*
908 * Convert topological properties into behaviour.
909 */
910
911 if (sd->flags & SD_ASYM_CPUCAPACITY) {
912 struct sched_domain *t = sd;
913
914 for_each_lower_domain(t)
915 t->flags |= SD_BALANCE_WAKE;
916 }
917
918 if (sd->flags & SD_SHARE_CPUCAPACITY) {
919 sd->flags |= SD_PREFER_SIBLING;
920 sd->imbalance_pct = 110;
921 sd->smt_gain = 1178; /* ~15% */
922
923 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
924 sd->imbalance_pct = 117;
925 sd->cache_nice_tries = 1;
926 sd->busy_idx = 2;
927
928#ifdef CONFIG_NUMA
929 } else if (sd->flags & SD_NUMA) {
930 sd->cache_nice_tries = 2;
931 sd->busy_idx = 3;
932 sd->idle_idx = 2;
933
934 sd->flags |= SD_SERIALIZE;
935 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
936 sd->flags &= ~(SD_BALANCE_EXEC |
937 SD_BALANCE_FORK |
938 SD_WAKE_AFFINE);
939 }
940
941#endif
942 } else {
943 sd->flags |= SD_PREFER_SIBLING;
944 sd->cache_nice_tries = 1;
945 sd->busy_idx = 2;
946 sd->idle_idx = 1;
947 }
948
949 /*
950 * For all levels sharing cache; connect a sched_domain_shared
951 * instance.
952 */
953 if (sd->flags & SD_SHARE_PKG_RESOURCES) {
954 sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
955 atomic_inc(&sd->shared->ref);
956 atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
957 }
958
959 sd->private = sdd;
960
961 return sd;
962}
963
964/*
965 * Topology list, bottom-up.
966 */
967static struct sched_domain_topology_level default_topology[] = {
968#ifdef CONFIG_SCHED_SMT
969 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
970#endif
971#ifdef CONFIG_SCHED_MC
972 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
973#endif
974 { cpu_cpu_mask, SD_INIT_NAME(DIE) },
975 { NULL, },
976};
977
978static struct sched_domain_topology_level *sched_domain_topology =
979 default_topology;
980
981#define for_each_sd_topology(tl) \
982 for (tl = sched_domain_topology; tl->mask; tl++)
983
984void set_sched_topology(struct sched_domain_topology_level *tl)
985{
986 if (WARN_ON_ONCE(sched_smp_initialized))
987 return;
988
989 sched_domain_topology = tl;
990}
991
992#ifdef CONFIG_NUMA
993
994static const struct cpumask *sd_numa_mask(int cpu)
995{
996 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
997}
998
999static void sched_numa_warn(const char *str)
1000{
1001 static int done = false;
1002 int i,j;
1003
1004 if (done)
1005 return;
1006
1007 done = true;
1008
1009 printk(KERN_WARNING "ERROR: %s\n\n", str);
1010
1011 for (i = 0; i < nr_node_ids; i++) {
1012 printk(KERN_WARNING " ");
1013 for (j = 0; j < nr_node_ids; j++)
1014 printk(KERN_CONT "%02d ", node_distance(i,j));
1015 printk(KERN_CONT "\n");
1016 }
1017 printk(KERN_WARNING "\n");
1018}
1019
1020bool find_numa_distance(int distance)
1021{
1022 int i;
1023
1024 if (distance == node_distance(0, 0))
1025 return true;
1026
1027 for (i = 0; i < sched_domains_numa_levels; i++) {
1028 if (sched_domains_numa_distance[i] == distance)
1029 return true;
1030 }
1031
1032 return false;
1033}
1034
1035/*
1036 * A system can have three types of NUMA topology:
1037 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
1038 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
1039 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
1040 *
1041 * The difference between a glueless mesh topology and a backplane
1042 * topology lies in whether communication between not directly
1043 * connected nodes goes through intermediary nodes (where programs
1044 * could run), or through backplane controllers. This affects
1045 * placement of programs.
1046 *
1047 * The type of topology can be discerned with the following tests:
1048 * - If the maximum distance between any nodes is 1 hop, the system
1049 * is directly connected.
1050 * - If for two nodes A and B, located N > 1 hops away from each other,
1051 * there is an intermediary node C, which is < N hops away from both
1052 * nodes A and B, the system is a glueless mesh.
1053 */
1054static void init_numa_topology_type(void)
1055{
1056 int a, b, c, n;
1057
1058 n = sched_max_numa_distance;
1059
1060 if (sched_domains_numa_levels <= 1) {
1061 sched_numa_topology_type = NUMA_DIRECT;
1062 return;
1063 }
1064
1065 for_each_online_node(a) {
1066 for_each_online_node(b) {
1067 /* Find two nodes furthest removed from each other. */
1068 if (node_distance(a, b) < n)
1069 continue;
1070
1071 /* Is there an intermediary node between a and b? */
1072 for_each_online_node(c) {
1073 if (node_distance(a, c) < n &&
1074 node_distance(b, c) < n) {
1075 sched_numa_topology_type =
1076 NUMA_GLUELESS_MESH;
1077 return;
1078 }
1079 }
1080
1081 sched_numa_topology_type = NUMA_BACKPLANE;
1082 return;
1083 }
1084 }
1085}
1086
1087void sched_init_numa(void)
1088{
1089 int next_distance, curr_distance = node_distance(0, 0);
1090 struct sched_domain_topology_level *tl;
1091 int level = 0;
1092 int i, j, k;
1093
1094 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
1095 if (!sched_domains_numa_distance)
1096 return;
1097
1098 /*
1099 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
1100 * unique distances in the node_distance() table.
1101 *
1102 * Assumes node_distance(0,j) includes all distances in
1103 * node_distance(i,j) in order to avoid cubic time.
1104 */
1105 next_distance = curr_distance;
1106 for (i = 0; i < nr_node_ids; i++) {
1107 for (j = 0; j < nr_node_ids; j++) {
1108 for (k = 0; k < nr_node_ids; k++) {
1109 int distance = node_distance(i, k);
1110
1111 if (distance > curr_distance &&
1112 (distance < next_distance ||
1113 next_distance == curr_distance))
1114 next_distance = distance;
1115
1116 /*
1117 * While not a strong assumption it would be nice to know
1118 * about cases where if node A is connected to B, B is not
1119 * equally connected to A.
1120 */
1121 if (sched_debug() && node_distance(k, i) != distance)
1122 sched_numa_warn("Node-distance not symmetric");
1123
1124 if (sched_debug() && i && !find_numa_distance(distance))
1125 sched_numa_warn("Node-0 not representative");
1126 }
1127 if (next_distance != curr_distance) {
1128 sched_domains_numa_distance[level++] = next_distance;
1129 sched_domains_numa_levels = level;
1130 curr_distance = next_distance;
1131 } else break;
1132 }
1133
1134 /*
1135 * In case of sched_debug() we verify the above assumption.
1136 */
1137 if (!sched_debug())
1138 break;
1139 }
1140
1141 if (!level)
1142 return;
1143
1144 /*
1145 * 'level' contains the number of unique distances, excluding the
1146 * identity distance node_distance(i,i).
1147 *
1148 * The sched_domains_numa_distance[] array includes the actual distance
1149 * numbers.
1150 */
1151
1152 /*
1153 * Here, we should temporarily reset sched_domains_numa_levels to 0.
1154 * If it fails to allocate memory for array sched_domains_numa_masks[][],
1155 * the array will contain less then 'level' members. This could be
1156 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
1157 * in other functions.
1158 *
1159 * We reset it to 'level' at the end of this function.
1160 */
1161 sched_domains_numa_levels = 0;
1162
1163 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
1164 if (!sched_domains_numa_masks)
1165 return;
1166
1167 /*
1168 * Now for each level, construct a mask per node which contains all
1169 * CPUs of nodes that are that many hops away from us.
1170 */
1171 for (i = 0; i < level; i++) {
1172 sched_domains_numa_masks[i] =
1173 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
1174 if (!sched_domains_numa_masks[i])
1175 return;
1176
1177 for (j = 0; j < nr_node_ids; j++) {
1178 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
1179 if (!mask)
1180 return;
1181
1182 sched_domains_numa_masks[i][j] = mask;
1183
1184 for_each_node(k) {
1185 if (node_distance(j, k) > sched_domains_numa_distance[i])
1186 continue;
1187
1188 cpumask_or(mask, mask, cpumask_of_node(k));
1189 }
1190 }
1191 }
1192
1193 /* Compute default topology size */
1194 for (i = 0; sched_domain_topology[i].mask; i++);
1195
1196 tl = kzalloc((i + level + 1) *
1197 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
1198 if (!tl)
1199 return;
1200
1201 /*
1202 * Copy the default topology bits..
1203 */
1204 for (i = 0; sched_domain_topology[i].mask; i++)
1205 tl[i] = sched_domain_topology[i];
1206
1207 /*
1208 * .. and append 'j' levels of NUMA goodness.
1209 */
1210 for (j = 0; j < level; i++, j++) {
1211 tl[i] = (struct sched_domain_topology_level){
1212 .mask = sd_numa_mask,
1213 .sd_flags = cpu_numa_flags,
1214 .flags = SDTL_OVERLAP,
1215 .numa_level = j,
1216 SD_INIT_NAME(NUMA)
1217 };
1218 }
1219
1220 sched_domain_topology = tl;
1221
1222 sched_domains_numa_levels = level;
1223 sched_max_numa_distance = sched_domains_numa_distance[level - 1];
1224
1225 init_numa_topology_type();
1226}
1227
1228void sched_domains_numa_masks_set(unsigned int cpu)
1229{
1230 int node = cpu_to_node(cpu);
1231 int i, j;
1232
1233 for (i = 0; i < sched_domains_numa_levels; i++) {
1234 for (j = 0; j < nr_node_ids; j++) {
1235 if (node_distance(j, node) <= sched_domains_numa_distance[i])
1236 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
1237 }
1238 }
1239}
1240
1241void sched_domains_numa_masks_clear(unsigned int cpu)
1242{
1243 int i, j;
1244
1245 for (i = 0; i < sched_domains_numa_levels; i++) {
1246 for (j = 0; j < nr_node_ids; j++)
1247 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
1248 }
1249}
1250
1251#endif /* CONFIG_NUMA */
1252
1253static int __sdt_alloc(const struct cpumask *cpu_map)
1254{
1255 struct sched_domain_topology_level *tl;
1256 int j;
1257
1258 for_each_sd_topology(tl) {
1259 struct sd_data *sdd = &tl->data;
1260
1261 sdd->sd = alloc_percpu(struct sched_domain *);
1262 if (!sdd->sd)
1263 return -ENOMEM;
1264
1265 sdd->sds = alloc_percpu(struct sched_domain_shared *);
1266 if (!sdd->sds)
1267 return -ENOMEM;
1268
1269 sdd->sg = alloc_percpu(struct sched_group *);
1270 if (!sdd->sg)
1271 return -ENOMEM;
1272
1273 sdd->sgc = alloc_percpu(struct sched_group_capacity *);
1274 if (!sdd->sgc)
1275 return -ENOMEM;
1276
1277 for_each_cpu(j, cpu_map) {
1278 struct sched_domain *sd;
1279 struct sched_domain_shared *sds;
1280 struct sched_group *sg;
1281 struct sched_group_capacity *sgc;
1282
1283 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
1284 GFP_KERNEL, cpu_to_node(j));
1285 if (!sd)
1286 return -ENOMEM;
1287
1288 *per_cpu_ptr(sdd->sd, j) = sd;
1289
1290 sds = kzalloc_node(sizeof(struct sched_domain_shared),
1291 GFP_KERNEL, cpu_to_node(j));
1292 if (!sds)
1293 return -ENOMEM;
1294
1295 *per_cpu_ptr(sdd->sds, j) = sds;
1296
1297 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
1298 GFP_KERNEL, cpu_to_node(j));
1299 if (!sg)
1300 return -ENOMEM;
1301
1302 sg->next = sg;
1303
1304 *per_cpu_ptr(sdd->sg, j) = sg;
1305
1306 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
1307 GFP_KERNEL, cpu_to_node(j));
1308 if (!sgc)
1309 return -ENOMEM;
1310
1311 *per_cpu_ptr(sdd->sgc, j) = sgc;
1312 }
1313 }
1314
1315 return 0;
1316}
1317
1318static void __sdt_free(const struct cpumask *cpu_map)
1319{
1320 struct sched_domain_topology_level *tl;
1321 int j;
1322
1323 for_each_sd_topology(tl) {
1324 struct sd_data *sdd = &tl->data;
1325
1326 for_each_cpu(j, cpu_map) {
1327 struct sched_domain *sd;
1328
1329 if (sdd->sd) {
1330 sd = *per_cpu_ptr(sdd->sd, j);
1331 if (sd && (sd->flags & SD_OVERLAP))
1332 free_sched_groups(sd->groups, 0);
1333 kfree(*per_cpu_ptr(sdd->sd, j));
1334 }
1335
1336 if (sdd->sds)
1337 kfree(*per_cpu_ptr(sdd->sds, j));
1338 if (sdd->sg)
1339 kfree(*per_cpu_ptr(sdd->sg, j));
1340 if (sdd->sgc)
1341 kfree(*per_cpu_ptr(sdd->sgc, j));
1342 }
1343 free_percpu(sdd->sd);
1344 sdd->sd = NULL;
1345 free_percpu(sdd->sds);
1346 sdd->sds = NULL;
1347 free_percpu(sdd->sg);
1348 sdd->sg = NULL;
1349 free_percpu(sdd->sgc);
1350 sdd->sgc = NULL;
1351 }
1352}
1353
1354struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
1355 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
1356 struct sched_domain *child, int cpu)
1357{
1358 struct sched_domain *sd = sd_init(tl, cpu_map, child, cpu);
1359
1360 if (child) {
1361 sd->level = child->level + 1;
1362 sched_domain_level_max = max(sched_domain_level_max, sd->level);
1363 child->parent = sd;
1364
1365 if (!cpumask_subset(sched_domain_span(child),
1366 sched_domain_span(sd))) {
1367 pr_err("BUG: arch topology borken\n");
1368#ifdef CONFIG_SCHED_DEBUG
1369 pr_err(" the %s domain not a subset of the %s domain\n",
1370 child->name, sd->name);
1371#endif
1372 /* Fixup, ensure @sd has at least @child cpus. */
1373 cpumask_or(sched_domain_span(sd),
1374 sched_domain_span(sd),
1375 sched_domain_span(child));
1376 }
1377
1378 }
1379 set_domain_attribute(sd, attr);
1380
1381 return sd;
1382}
1383
1384/*
1385 * Build sched domains for a given set of CPUs and attach the sched domains
1386 * to the individual CPUs
1387 */
1388static int
1389build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr)
1390{
1391 enum s_alloc alloc_state;
1392 struct sched_domain *sd;
1393 struct s_data d;
1394 struct rq *rq = NULL;
1395 int i, ret = -ENOMEM;
1396
1397 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
1398 if (alloc_state != sa_rootdomain)
1399 goto error;
1400
1401 /* Set up domains for CPUs specified by the cpu_map: */
1402 for_each_cpu(i, cpu_map) {
1403 struct sched_domain_topology_level *tl;
1404
1405 sd = NULL;
1406 for_each_sd_topology(tl) {
1407 sd = build_sched_domain(tl, cpu_map, attr, sd, i);
1408 if (tl == sched_domain_topology)
1409 *per_cpu_ptr(d.sd, i) = sd;
1410 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
1411 sd->flags |= SD_OVERLAP;
1412 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
1413 break;
1414 }
1415 }
1416
1417 /* Build the groups for the domains */
1418 for_each_cpu(i, cpu_map) {
1419 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
1420 sd->span_weight = cpumask_weight(sched_domain_span(sd));
1421 if (sd->flags & SD_OVERLAP) {
1422 if (build_overlap_sched_groups(sd, i))
1423 goto error;
1424 } else {
1425 if (build_sched_groups(sd, i))
1426 goto error;
1427 }
1428 }
1429 }
1430
1431 /* Calculate CPU capacity for physical packages and nodes */
1432 for (i = nr_cpumask_bits-1; i >= 0; i--) {
1433 if (!cpumask_test_cpu(i, cpu_map))
1434 continue;
1435
1436 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
1437 claim_allocations(i, sd);
1438 init_sched_groups_capacity(i, sd);
1439 }
1440 }
1441
1442 /* Attach the domains */
1443 rcu_read_lock();
1444 for_each_cpu(i, cpu_map) {
1445 rq = cpu_rq(i);
1446 sd = *per_cpu_ptr(d.sd, i);
1447
1448 /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
1449 if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
1450 WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
1451
1452 cpu_attach_domain(sd, d.rd, i);
1453 }
1454 rcu_read_unlock();
1455
1456 if (rq && sched_debug_enabled) {
1457 pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
1458 cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
1459 }
1460
1461 ret = 0;
1462error:
1463 __free_domain_allocs(&d, alloc_state, cpu_map);
1464 return ret;
1465}
1466
1467/* Current sched domains: */
1468static cpumask_var_t *doms_cur;
1469
1470/* Number of sched domains in 'doms_cur': */
1471static int ndoms_cur;
1472
1473/* Attribues of custom domains in 'doms_cur' */
1474static struct sched_domain_attr *dattr_cur;
1475
1476/*
1477 * Special case: If a kmalloc() of a doms_cur partition (array of
1478 * cpumask) fails, then fallback to a single sched domain,
1479 * as determined by the single cpumask fallback_doms.
1480 */
1481cpumask_var_t fallback_doms;
1482
1483/*
1484 * arch_update_cpu_topology lets virtualized architectures update the
1485 * CPU core maps. It is supposed to return 1 if the topology changed
1486 * or 0 if it stayed the same.
1487 */
1488int __weak arch_update_cpu_topology(void)
1489{
1490 return 0;
1491}
1492
1493cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
1494{
1495 int i;
1496 cpumask_var_t *doms;
1497
1498 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
1499 if (!doms)
1500 return NULL;
1501 for (i = 0; i < ndoms; i++) {
1502 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
1503 free_sched_domains(doms, i);
1504 return NULL;
1505 }
1506 }
1507 return doms;
1508}
1509
1510void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
1511{
1512 unsigned int i;
1513 for (i = 0; i < ndoms; i++)
1514 free_cpumask_var(doms[i]);
1515 kfree(doms);
1516}
1517
1518/*
1519 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
1520 * For now this just excludes isolated CPUs, but could be used to
1521 * exclude other special cases in the future.
1522 */
1523int init_sched_domains(const struct cpumask *cpu_map)
1524{
1525 int err;
1526
1527 arch_update_cpu_topology();
1528 ndoms_cur = 1;
1529 doms_cur = alloc_sched_domains(ndoms_cur);
1530 if (!doms_cur)
1531 doms_cur = &fallback_doms;
1532 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
1533 err = build_sched_domains(doms_cur[0], NULL);
1534 register_sched_domain_sysctl();
1535
1536 return err;
1537}
1538
1539/*
1540 * Detach sched domains from a group of CPUs specified in cpu_map
1541 * These CPUs will now be attached to the NULL domain
1542 */
1543static void detach_destroy_domains(const struct cpumask *cpu_map)
1544{
1545 int i;
1546
1547 rcu_read_lock();
1548 for_each_cpu(i, cpu_map)
1549 cpu_attach_domain(NULL, &def_root_domain, i);
1550 rcu_read_unlock();
1551}
1552
1553/* handle null as "default" */
1554static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
1555 struct sched_domain_attr *new, int idx_new)
1556{
1557 struct sched_domain_attr tmp;
1558
1559 /* Fast path: */
1560 if (!new && !cur)
1561 return 1;
1562
1563 tmp = SD_ATTR_INIT;
1564 return !memcmp(cur ? (cur + idx_cur) : &tmp,
1565 new ? (new + idx_new) : &tmp,
1566 sizeof(struct sched_domain_attr));
1567}
1568
1569/*
1570 * Partition sched domains as specified by the 'ndoms_new'
1571 * cpumasks in the array doms_new[] of cpumasks. This compares
1572 * doms_new[] to the current sched domain partitioning, doms_cur[].
1573 * It destroys each deleted domain and builds each new domain.
1574 *
1575 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
1576 * The masks don't intersect (don't overlap.) We should setup one
1577 * sched domain for each mask. CPUs not in any of the cpumasks will
1578 * not be load balanced. If the same cpumask appears both in the
1579 * current 'doms_cur' domains and in the new 'doms_new', we can leave
1580 * it as it is.
1581 *
1582 * The passed in 'doms_new' should be allocated using
1583 * alloc_sched_domains. This routine takes ownership of it and will
1584 * free_sched_domains it when done with it. If the caller failed the
1585 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
1586 * and partition_sched_domains() will fallback to the single partition
1587 * 'fallback_doms', it also forces the domains to be rebuilt.
1588 *
1589 * If doms_new == NULL it will be replaced with cpu_online_mask.
1590 * ndoms_new == 0 is a special case for destroying existing domains,
1591 * and it will not create the default domain.
1592 *
1593 * Call with hotplug lock held
1594 */
1595void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1596 struct sched_domain_attr *dattr_new)
1597{
1598 int i, j, n;
1599 int new_topology;
1600
1601 mutex_lock(&sched_domains_mutex);
1602
1603 /* Always unregister in case we don't destroy any domains: */
1604 unregister_sched_domain_sysctl();
1605
1606 /* Let the architecture update CPU core mappings: */
1607 new_topology = arch_update_cpu_topology();
1608
1609 n = doms_new ? ndoms_new : 0;
1610
1611 /* Destroy deleted domains: */
1612 for (i = 0; i < ndoms_cur; i++) {
1613 for (j = 0; j < n && !new_topology; j++) {
1614 if (cpumask_equal(doms_cur[i], doms_new[j])
1615 && dattrs_equal(dattr_cur, i, dattr_new, j))
1616 goto match1;
1617 }
1618 /* No match - a current sched domain not in new doms_new[] */
1619 detach_destroy_domains(doms_cur[i]);
1620match1:
1621 ;
1622 }
1623
1624 n = ndoms_cur;
1625 if (doms_new == NULL) {
1626 n = 0;
1627 doms_new = &fallback_doms;
1628 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
1629 WARN_ON_ONCE(dattr_new);
1630 }
1631
1632 /* Build new domains: */
1633 for (i = 0; i < ndoms_new; i++) {
1634 for (j = 0; j < n && !new_topology; j++) {
1635 if (cpumask_equal(doms_new[i], doms_cur[j])
1636 && dattrs_equal(dattr_new, i, dattr_cur, j))
1637 goto match2;
1638 }
1639 /* No match - add a new doms_new */
1640 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
1641match2:
1642 ;
1643 }
1644
1645 /* Remember the new sched domains: */
1646 if (doms_cur != &fallback_doms)
1647 free_sched_domains(doms_cur, ndoms_cur);
1648
1649 kfree(dattr_cur);
1650 doms_cur = doms_new;
1651 dattr_cur = dattr_new;
1652 ndoms_cur = ndoms_new;
1653
1654 register_sched_domain_sysctl();
1655
1656 mutex_unlock(&sched_domains_mutex);
1657}
1658
generated by cgit v1.2.2 (git 2.25.0) at 2025-05-01 03:44:30 -0400