2 * Scheduler topology setup/handling methods
4 #include <linux/sched.h>
5 #include <linux/mutex.h>
9 DEFINE_MUTEX(sched_domains_mutex
);
11 /* Protected by sched_domains_mutex: */
12 cpumask_var_t sched_domains_tmpmask
;
13 cpumask_var_t sched_domains_tmpmask2
;
15 #ifdef CONFIG_SCHED_DEBUG
17 static int __init
sched_debug_setup(char *str
)
19 sched_debug_enabled
= true;
23 early_param("sched_debug", sched_debug_setup
);
25 static inline bool sched_debug(void)
27 return sched_debug_enabled
;
30 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
31 struct cpumask
*groupmask
)
33 struct sched_group
*group
= sd
->groups
;
35 cpumask_clear(groupmask
);
37 printk(KERN_DEBUG
"%*s domain-%d: ", level
, "", level
);
39 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
40 printk("does not load-balance\n");
42 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
47 printk(KERN_CONT
"span=%*pbl level=%s\n",
48 cpumask_pr_args(sched_domain_span(sd
)), sd
->name
);
50 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
51 printk(KERN_ERR
"ERROR: domain->span does not contain "
54 if (!cpumask_test_cpu(cpu
, sched_group_span(group
))) {
55 printk(KERN_ERR
"ERROR: domain->groups does not contain"
59 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
63 printk(KERN_ERR
"ERROR: group is NULL\n");
67 if (!cpumask_weight(sched_group_span(group
))) {
68 printk(KERN_CONT
"\n");
69 printk(KERN_ERR
"ERROR: empty group\n");
73 if (!(sd
->flags
& SD_OVERLAP
) &&
74 cpumask_intersects(groupmask
, sched_group_span(group
))) {
75 printk(KERN_CONT
"\n");
76 printk(KERN_ERR
"ERROR: repeated CPUs\n");
80 cpumask_or(groupmask
, groupmask
, sched_group_span(group
));
82 printk(KERN_CONT
" %d:{ span=%*pbl",
84 cpumask_pr_args(sched_group_span(group
)));
86 if ((sd
->flags
& SD_OVERLAP
) &&
87 !cpumask_equal(group_balance_mask(group
), sched_group_span(group
))) {
88 printk(KERN_CONT
" mask=%*pbl",
89 cpumask_pr_args(group_balance_mask(group
)));
92 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
)
93 printk(KERN_CONT
" cap=%lu", group
->sgc
->capacity
);
95 if (group
== sd
->groups
&& sd
->child
&&
96 !cpumask_equal(sched_domain_span(sd
->child
),
97 sched_group_span(group
))) {
98 printk(KERN_ERR
"ERROR: domain->groups does not match domain->child\n");
101 printk(KERN_CONT
" }");
105 if (group
!= sd
->groups
)
106 printk(KERN_CONT
",");
108 } while (group
!= sd
->groups
);
109 printk(KERN_CONT
"\n");
111 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
112 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
115 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
116 printk(KERN_ERR
"ERROR: parent span is not a superset "
117 "of domain->span\n");
121 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
125 if (!sched_debug_enabled
)
129 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
133 printk(KERN_DEBUG
"CPU%d attaching sched-domain(s):\n", cpu
);
136 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
144 #else /* !CONFIG_SCHED_DEBUG */
146 # define sched_debug_enabled 0
147 # define sched_domain_debug(sd, cpu) do { } while (0)
148 static inline bool sched_debug(void)
152 #endif /* CONFIG_SCHED_DEBUG */
154 static int sd_degenerate(struct sched_domain
*sd
)
156 if (cpumask_weight(sched_domain_span(sd
)) == 1)
159 /* Following flags need at least 2 groups */
160 if (sd
->flags
& (SD_LOAD_BALANCE
|
164 SD_SHARE_CPUCAPACITY
|
165 SD_ASYM_CPUCAPACITY
|
166 SD_SHARE_PKG_RESOURCES
|
167 SD_SHARE_POWERDOMAIN
)) {
168 if (sd
->groups
!= sd
->groups
->next
)
172 /* Following flags don't use groups */
173 if (sd
->flags
& (SD_WAKE_AFFINE
))
180 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
182 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
184 if (sd_degenerate(parent
))
187 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
190 /* Flags needing groups don't count if only 1 group in parent */
191 if (parent
->groups
== parent
->groups
->next
) {
192 pflags
&= ~(SD_LOAD_BALANCE
|
196 SD_ASYM_CPUCAPACITY
|
197 SD_SHARE_CPUCAPACITY
|
198 SD_SHARE_PKG_RESOURCES
|
200 SD_SHARE_POWERDOMAIN
);
201 if (nr_node_ids
== 1)
202 pflags
&= ~SD_SERIALIZE
;
204 if (~cflags
& pflags
)
210 static void free_rootdomain(struct rcu_head
*rcu
)
212 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
214 cpupri_cleanup(&rd
->cpupri
);
215 cpudl_cleanup(&rd
->cpudl
);
216 free_cpumask_var(rd
->dlo_mask
);
217 free_cpumask_var(rd
->rto_mask
);
218 free_cpumask_var(rd
->online
);
219 free_cpumask_var(rd
->span
);
223 void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
225 struct root_domain
*old_rd
= NULL
;
228 raw_spin_lock_irqsave(&rq
->lock
, flags
);
233 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
236 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
239 * If we dont want to free the old_rd yet then
240 * set old_rd to NULL to skip the freeing later
243 if (!atomic_dec_and_test(&old_rd
->refcount
))
247 atomic_inc(&rd
->refcount
);
250 cpumask_set_cpu(rq
->cpu
, rd
->span
);
251 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
254 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
257 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
260 static int init_rootdomain(struct root_domain
*rd
)
262 if (!zalloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
264 if (!zalloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
266 if (!zalloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
268 if (!zalloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
271 init_dl_bw(&rd
->dl_bw
);
272 if (cpudl_init(&rd
->cpudl
) != 0)
275 if (cpupri_init(&rd
->cpupri
) != 0)
280 cpudl_cleanup(&rd
->cpudl
);
282 free_cpumask_var(rd
->rto_mask
);
284 free_cpumask_var(rd
->dlo_mask
);
286 free_cpumask_var(rd
->online
);
288 free_cpumask_var(rd
->span
);
294 * By default the system creates a single root-domain with all CPUs as
295 * members (mimicking the global state we have today).
297 struct root_domain def_root_domain
;
299 void init_defrootdomain(void)
301 init_rootdomain(&def_root_domain
);
303 atomic_set(&def_root_domain
.refcount
, 1);
306 static struct root_domain
*alloc_rootdomain(void)
308 struct root_domain
*rd
;
310 rd
= kzalloc(sizeof(*rd
), GFP_KERNEL
);
314 if (init_rootdomain(rd
) != 0) {
322 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
324 struct sched_group
*tmp
, *first
;
333 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
336 if (atomic_dec_and_test(&sg
->ref
))
339 } while (sg
!= first
);
342 static void destroy_sched_domain(struct sched_domain
*sd
)
345 * A normal sched domain may have multiple group references, an
346 * overlapping domain, having private groups, only one. Iterate,
347 * dropping group/capacity references, freeing where none remain.
349 free_sched_groups(sd
->groups
, 1);
351 if (sd
->shared
&& atomic_dec_and_test(&sd
->shared
->ref
))
356 static void destroy_sched_domains_rcu(struct rcu_head
*rcu
)
358 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
361 struct sched_domain
*parent
= sd
->parent
;
362 destroy_sched_domain(sd
);
367 static void destroy_sched_domains(struct sched_domain
*sd
)
370 call_rcu(&sd
->rcu
, destroy_sched_domains_rcu
);
374 * Keep a special pointer to the highest sched_domain that has
375 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
376 * allows us to avoid some pointer chasing select_idle_sibling().
378 * Also keep a unique ID per domain (we use the first CPU number in
379 * the cpumask of the domain), this allows us to quickly tell if
380 * two CPUs are in the same cache domain, see cpus_share_cache().
382 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
383 DEFINE_PER_CPU(int, sd_llc_size
);
384 DEFINE_PER_CPU(int, sd_llc_id
);
385 DEFINE_PER_CPU(struct sched_domain_shared
*, sd_llc_shared
);
386 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
387 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
389 static void update_top_cache_domain(int cpu
)
391 struct sched_domain_shared
*sds
= NULL
;
392 struct sched_domain
*sd
;
396 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
398 id
= cpumask_first(sched_domain_span(sd
));
399 size
= cpumask_weight(sched_domain_span(sd
));
403 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
404 per_cpu(sd_llc_size
, cpu
) = size
;
405 per_cpu(sd_llc_id
, cpu
) = id
;
406 rcu_assign_pointer(per_cpu(sd_llc_shared
, cpu
), sds
);
408 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
409 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
411 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
412 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
416 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
417 * hold the hotplug lock.
420 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
422 struct rq
*rq
= cpu_rq(cpu
);
423 struct sched_domain
*tmp
;
425 /* Remove the sched domains which do not contribute to scheduling. */
426 for (tmp
= sd
; tmp
; ) {
427 struct sched_domain
*parent
= tmp
->parent
;
431 if (sd_parent_degenerate(tmp
, parent
)) {
432 tmp
->parent
= parent
->parent
;
434 parent
->parent
->child
= tmp
;
436 * Transfer SD_PREFER_SIBLING down in case of a
437 * degenerate parent; the spans match for this
438 * so the property transfers.
440 if (parent
->flags
& SD_PREFER_SIBLING
)
441 tmp
->flags
|= SD_PREFER_SIBLING
;
442 destroy_sched_domain(parent
);
447 if (sd
&& sd_degenerate(sd
)) {
450 destroy_sched_domain(tmp
);
455 sched_domain_debug(sd
, cpu
);
457 rq_attach_root(rq
, rd
);
459 rcu_assign_pointer(rq
->sd
, sd
);
460 dirty_sched_domain_sysctl(cpu
);
461 destroy_sched_domains(tmp
);
463 update_top_cache_domain(cpu
);
466 /* Setup the mask of CPUs configured for isolated domains */
467 static int __init
isolated_cpu_setup(char *str
)
471 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
472 ret
= cpulist_parse(str
, cpu_isolated_map
);
474 pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids
);
479 __setup("isolcpus=", isolated_cpu_setup
);
482 struct sched_domain
** __percpu sd
;
483 struct root_domain
*rd
;
494 * Return the canonical balance CPU for this group, this is the first CPU
495 * of this group that's also in the balance mask.
497 * The balance mask are all those CPUs that could actually end up at this
498 * group. See build_balance_mask().
500 * Also see should_we_balance().
502 int group_balance_cpu(struct sched_group
*sg
)
504 return cpumask_first(group_balance_mask(sg
));
509 * NUMA topology (first read the regular topology blurb below)
511 * Given a node-distance table, for example:
519 * which represents a 4 node ring topology like:
527 * We want to construct domains and groups to represent this. The way we go
528 * about doing this is to build the domains on 'hops'. For each NUMA level we
529 * construct the mask of all nodes reachable in @level hops.
531 * For the above NUMA topology that gives 3 levels:
533 * NUMA-2 0-3 0-3 0-3 0-3
534 * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2}
536 * NUMA-1 0-1,3 0-2 1-3 0,2-3
537 * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3}
542 * As can be seen; things don't nicely line up as with the regular topology.
543 * When we iterate a domain in child domain chunks some nodes can be
544 * represented multiple times -- hence the "overlap" naming for this part of
547 * In order to minimize this overlap, we only build enough groups to cover the
548 * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3.
552 * - the first group of each domain is its child domain; this
553 * gets us the first 0-1,3
554 * - the only uncovered node is 2, who's child domain is 1-3.
556 * However, because of the overlap, computing a unique CPU for each group is
557 * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both
558 * groups include the CPUs of Node-0, while those CPUs would not in fact ever
559 * end up at those groups (they would end up in group: 0-1,3).
561 * To correct this we have to introduce the group balance mask. This mask
562 * will contain those CPUs in the group that can reach this group given the
563 * (child) domain tree.
565 * With this we can once again compute balance_cpu and sched_group_capacity
568 * XXX include words on how balance_cpu is unique and therefore can be
569 * used for sched_group_capacity links.
572 * Another 'interesting' topology is:
580 * Which looks a little like:
588 * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3
591 * This leads to a few particularly weird cases where the sched_domain's are
592 * not of the same number for each cpu. Consider:
595 * groups: {0-2},{1-3} {1-3},{0-2}
597 * NUMA-1 0-2 0-3 0-3 1-3
605 * Build the balance mask; it contains only those CPUs that can arrive at this
606 * group and should be considered to continue balancing.
608 * We do this during the group creation pass, therefore the group information
609 * isn't complete yet, however since each group represents a (child) domain we
610 * can fully construct this using the sched_domain bits (which are already
614 build_balance_mask(struct sched_domain
*sd
, struct sched_group
*sg
, struct cpumask
*mask
)
616 const struct cpumask
*sg_span
= sched_group_span(sg
);
617 struct sd_data
*sdd
= sd
->private;
618 struct sched_domain
*sibling
;
623 for_each_cpu(i
, sg_span
) {
624 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
627 * Can happen in the asymmetric case, where these siblings are
628 * unused. The mask will not be empty because those CPUs that
629 * do have the top domain _should_ span the domain.
634 /* If we would not end up here, we can't continue from here */
635 if (!cpumask_equal(sg_span
, sched_domain_span(sibling
->child
)))
638 cpumask_set_cpu(i
, mask
);
641 /* We must not have empty masks here */
642 WARN_ON_ONCE(cpumask_empty(mask
));
646 * XXX: This creates per-node group entries; since the load-balancer will
647 * immediately access remote memory to construct this group's load-balance
648 * statistics having the groups node local is of dubious benefit.
650 static struct sched_group
*
651 build_group_from_child_sched_domain(struct sched_domain
*sd
, int cpu
)
653 struct sched_group
*sg
;
654 struct cpumask
*sg_span
;
656 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
657 GFP_KERNEL
, cpu_to_node(cpu
));
662 sg_span
= sched_group_span(sg
);
664 cpumask_copy(sg_span
, sched_domain_span(sd
->child
));
666 cpumask_copy(sg_span
, sched_domain_span(sd
));
668 atomic_inc(&sg
->ref
);
672 static void init_overlap_sched_group(struct sched_domain
*sd
,
673 struct sched_group
*sg
)
675 struct cpumask
*mask
= sched_domains_tmpmask2
;
676 struct sd_data
*sdd
= sd
->private;
677 struct cpumask
*sg_span
;
680 build_balance_mask(sd
, sg
, mask
);
681 cpu
= cpumask_first_and(sched_group_span(sg
), mask
);
683 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
684 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
685 cpumask_copy(group_balance_mask(sg
), mask
);
687 WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg
), mask
));
690 * Initialize sgc->capacity such that even if we mess up the
691 * domains and no possible iteration will get us here, we won't
694 sg_span
= sched_group_span(sg
);
695 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
696 sg
->sgc
->min_capacity
= SCHED_CAPACITY_SCALE
;
700 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
702 struct sched_group
*first
= NULL
, *last
= NULL
, *sg
;
703 const struct cpumask
*span
= sched_domain_span(sd
);
704 struct cpumask
*covered
= sched_domains_tmpmask
;
705 struct sd_data
*sdd
= sd
->private;
706 struct sched_domain
*sibling
;
709 cpumask_clear(covered
);
711 for_each_cpu_wrap(i
, span
, cpu
) {
712 struct cpumask
*sg_span
;
714 if (cpumask_test_cpu(i
, covered
))
717 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
720 * Asymmetric node setups can result in situations where the
721 * domain tree is of unequal depth, make sure to skip domains
722 * that already cover the entire range.
724 * In that case build_sched_domains() will have terminated the
725 * iteration early and our sibling sd spans will be empty.
726 * Domains should always include the CPU they're built on, so
729 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
732 sg
= build_group_from_child_sched_domain(sibling
, cpu
);
736 sg_span
= sched_group_span(sg
);
737 cpumask_or(covered
, covered
, sg_span
);
739 init_overlap_sched_group(sd
, sg
);
753 free_sched_groups(first
, 0);
760 * Package topology (also see the load-balance blurb in fair.c)
762 * The scheduler builds a tree structure to represent a number of important
763 * topology features. By default (default_topology[]) these include:
765 * - Simultaneous multithreading (SMT)
766 * - Multi-Core Cache (MC)
769 * Where the last one more or less denotes everything up to a NUMA node.
771 * The tree consists of 3 primary data structures:
773 * sched_domain -> sched_group -> sched_group_capacity
777 * The sched_domains are per-cpu and have a two way link (parent & child) and
778 * denote the ever growing mask of CPUs belonging to that level of topology.
780 * Each sched_domain has a circular (double) linked list of sched_group's, each
781 * denoting the domains of the level below (or individual CPUs in case of the
782 * first domain level). The sched_group linked by a sched_domain includes the
783 * CPU of that sched_domain [*].
785 * Take for instance a 2 threaded, 2 core, 2 cache cluster part:
787 * CPU 0 1 2 3 4 5 6 7
791 * SMT [ ] [ ] [ ] [ ]
795 * DIE 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7
796 * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7
797 * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7
799 * CPU 0 1 2 3 4 5 6 7
801 * One way to think about it is: sched_domain moves you up and down among these
802 * topology levels, while sched_group moves you sideways through it, at child
803 * domain granularity.
805 * sched_group_capacity ensures each unique sched_group has shared storage.
807 * There are two related construction problems, both require a CPU that
808 * uniquely identify each group (for a given domain):
810 * - The first is the balance_cpu (see should_we_balance() and the
811 * load-balance blub in fair.c); for each group we only want 1 CPU to
812 * continue balancing at a higher domain.
814 * - The second is the sched_group_capacity; we want all identical groups
815 * to share a single sched_group_capacity.
817 * Since these topologies are exclusive by construction. That is, its
818 * impossible for an SMT thread to belong to multiple cores, and cores to
819 * be part of multiple caches. There is a very clear and unique location
820 * for each CPU in the hierarchy.
822 * Therefore computing a unique CPU for each group is trivial (the iteration
823 * mask is redundant and set all 1s; all CPUs in a group will end up at _that_
824 * group), we can simply pick the first CPU in each group.
827 * [*] in other words, the first group of each domain is its child domain.
830 static struct sched_group
*get_group(int cpu
, struct sd_data
*sdd
)
832 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
833 struct sched_domain
*child
= sd
->child
;
834 struct sched_group
*sg
;
837 cpu
= cpumask_first(sched_domain_span(child
));
839 sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
840 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
842 /* For claim_allocations: */
843 atomic_inc(&sg
->ref
);
844 atomic_inc(&sg
->sgc
->ref
);
847 cpumask_copy(sched_group_span(sg
), sched_domain_span(child
));
848 cpumask_copy(group_balance_mask(sg
), sched_group_span(sg
));
850 cpumask_set_cpu(cpu
, sched_group_span(sg
));
851 cpumask_set_cpu(cpu
, group_balance_mask(sg
));
854 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sched_group_span(sg
));
855 sg
->sgc
->min_capacity
= SCHED_CAPACITY_SCALE
;
861 * build_sched_groups will build a circular linked list of the groups
862 * covered by the given span, and will set each group's ->cpumask correctly,
863 * and ->cpu_capacity to 0.
865 * Assumes the sched_domain tree is fully constructed
868 build_sched_groups(struct sched_domain
*sd
, int cpu
)
870 struct sched_group
*first
= NULL
, *last
= NULL
;
871 struct sd_data
*sdd
= sd
->private;
872 const struct cpumask
*span
= sched_domain_span(sd
);
873 struct cpumask
*covered
;
876 lockdep_assert_held(&sched_domains_mutex
);
877 covered
= sched_domains_tmpmask
;
879 cpumask_clear(covered
);
881 for_each_cpu_wrap(i
, span
, cpu
) {
882 struct sched_group
*sg
;
884 if (cpumask_test_cpu(i
, covered
))
887 sg
= get_group(i
, sdd
);
889 cpumask_or(covered
, covered
, sched_group_span(sg
));
904 * Initialize sched groups cpu_capacity.
906 * cpu_capacity indicates the capacity of sched group, which is used while
907 * distributing the load between different sched groups in a sched domain.
908 * Typically cpu_capacity for all the groups in a sched domain will be same
909 * unless there are asymmetries in the topology. If there are asymmetries,
910 * group having more cpu_capacity will pickup more load compared to the
911 * group having less cpu_capacity.
913 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
915 struct sched_group
*sg
= sd
->groups
;
920 int cpu
, max_cpu
= -1;
922 sg
->group_weight
= cpumask_weight(sched_group_span(sg
));
924 if (!(sd
->flags
& SD_ASYM_PACKING
))
927 for_each_cpu(cpu
, sched_group_span(sg
)) {
930 else if (sched_asym_prefer(cpu
, max_cpu
))
933 sg
->asym_prefer_cpu
= max_cpu
;
937 } while (sg
!= sd
->groups
);
939 if (cpu
!= group_balance_cpu(sg
))
942 update_group_capacity(sd
, cpu
);
946 * Initializers for schedule domains
947 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
950 static int default_relax_domain_level
= -1;
951 int sched_domain_level_max
;
953 static int __init
setup_relax_domain_level(char *str
)
955 if (kstrtoint(str
, 0, &default_relax_domain_level
))
956 pr_warn("Unable to set relax_domain_level\n");
960 __setup("relax_domain_level=", setup_relax_domain_level
);
962 static void set_domain_attribute(struct sched_domain
*sd
,
963 struct sched_domain_attr
*attr
)
967 if (!attr
|| attr
->relax_domain_level
< 0) {
968 if (default_relax_domain_level
< 0)
971 request
= default_relax_domain_level
;
973 request
= attr
->relax_domain_level
;
974 if (request
< sd
->level
) {
975 /* Turn off idle balance on this domain: */
976 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
978 /* Turn on idle balance on this domain: */
979 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
983 static void __sdt_free(const struct cpumask
*cpu_map
);
984 static int __sdt_alloc(const struct cpumask
*cpu_map
);
986 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
987 const struct cpumask
*cpu_map
)
991 if (!atomic_read(&d
->rd
->refcount
))
992 free_rootdomain(&d
->rd
->rcu
);
1006 __visit_domain_allocation_hell(struct s_data
*d
, const struct cpumask
*cpu_map
)
1008 memset(d
, 0, sizeof(*d
));
1010 if (__sdt_alloc(cpu_map
))
1011 return sa_sd_storage
;
1012 d
->sd
= alloc_percpu(struct sched_domain
*);
1014 return sa_sd_storage
;
1015 d
->rd
= alloc_rootdomain();
1018 return sa_rootdomain
;
1022 * NULL the sd_data elements we've used to build the sched_domain and
1023 * sched_group structure so that the subsequent __free_domain_allocs()
1024 * will not free the data we're using.
1026 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
1028 struct sd_data
*sdd
= sd
->private;
1030 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
1031 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
1033 if (atomic_read(&(*per_cpu_ptr(sdd
->sds
, cpu
))->ref
))
1034 *per_cpu_ptr(sdd
->sds
, cpu
) = NULL
;
1036 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
1037 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
1039 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
1040 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
1044 static int sched_domains_numa_levels
;
1045 enum numa_topology_type sched_numa_topology_type
;
1046 static int *sched_domains_numa_distance
;
1047 int sched_max_numa_distance
;
1048 static struct cpumask
***sched_domains_numa_masks
;
1049 static int sched_domains_curr_level
;
1053 * SD_flags allowed in topology descriptions.
1055 * These flags are purely descriptive of the topology and do not prescribe
1056 * behaviour. Behaviour is artificial and mapped in the below sd_init()
1059 * SD_SHARE_CPUCAPACITY - describes SMT topologies
1060 * SD_SHARE_PKG_RESOURCES - describes shared caches
1061 * SD_NUMA - describes NUMA topologies
1062 * SD_SHARE_POWERDOMAIN - describes shared power domain
1063 * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies
1065 * Odd one out, which beside describing the topology has a quirk also
1066 * prescribes the desired behaviour that goes along with it:
1068 * SD_ASYM_PACKING - describes SMT quirks
1070 #define TOPOLOGY_SD_FLAGS \
1071 (SD_SHARE_CPUCAPACITY | \
1072 SD_SHARE_PKG_RESOURCES | \
1075 SD_ASYM_CPUCAPACITY | \
1076 SD_SHARE_POWERDOMAIN)
1078 static struct sched_domain
*
1079 sd_init(struct sched_domain_topology_level
*tl
,
1080 const struct cpumask
*cpu_map
,
1081 struct sched_domain
*child
, int cpu
)
1083 struct sd_data
*sdd
= &tl
->data
;
1084 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
1085 int sd_id
, sd_weight
, sd_flags
= 0;
1089 * Ugly hack to pass state to sd_numa_mask()...
1091 sched_domains_curr_level
= tl
->numa_level
;
1094 sd_weight
= cpumask_weight(tl
->mask(cpu
));
1097 sd_flags
= (*tl
->sd_flags
)();
1098 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
1099 "wrong sd_flags in topology description\n"))
1100 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
1102 *sd
= (struct sched_domain
){
1103 .min_interval
= sd_weight
,
1104 .max_interval
= 2*sd_weight
,
1106 .imbalance_pct
= 125,
1108 .cache_nice_tries
= 0,
1115 .flags
= 1*SD_LOAD_BALANCE
1116 | 1*SD_BALANCE_NEWIDLE
1121 | 0*SD_SHARE_CPUCAPACITY
1122 | 0*SD_SHARE_PKG_RESOURCES
1124 | 0*SD_PREFER_SIBLING
1129 .last_balance
= jiffies
,
1130 .balance_interval
= sd_weight
,
1132 .max_newidle_lb_cost
= 0,
1133 .next_decay_max_lb_cost
= jiffies
,
1135 #ifdef CONFIG_SCHED_DEBUG
1140 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
1141 sd_id
= cpumask_first(sched_domain_span(sd
));
1144 * Convert topological properties into behaviour.
1147 if (sd
->flags
& SD_ASYM_CPUCAPACITY
) {
1148 struct sched_domain
*t
= sd
;
1150 for_each_lower_domain(t
)
1151 t
->flags
|= SD_BALANCE_WAKE
;
1154 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
1155 sd
->flags
|= SD_PREFER_SIBLING
;
1156 sd
->imbalance_pct
= 110;
1157 sd
->smt_gain
= 1178; /* ~15% */
1159 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
1160 sd
->imbalance_pct
= 117;
1161 sd
->cache_nice_tries
= 1;
1165 } else if (sd
->flags
& SD_NUMA
) {
1166 sd
->cache_nice_tries
= 2;
1170 sd
->flags
|= SD_SERIALIZE
;
1171 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
1172 sd
->flags
&= ~(SD_BALANCE_EXEC
|
1179 sd
->flags
|= SD_PREFER_SIBLING
;
1180 sd
->cache_nice_tries
= 1;
1186 * For all levels sharing cache; connect a sched_domain_shared
1189 if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
1190 sd
->shared
= *per_cpu_ptr(sdd
->sds
, sd_id
);
1191 atomic_inc(&sd
->shared
->ref
);
1192 atomic_set(&sd
->shared
->nr_busy_cpus
, sd_weight
);
1201 * Topology list, bottom-up.
1203 static struct sched_domain_topology_level default_topology
[] = {
1204 #ifdef CONFIG_SCHED_SMT
1205 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
1207 #ifdef CONFIG_SCHED_MC
1208 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
1210 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
1214 static struct sched_domain_topology_level
*sched_domain_topology
=
1217 #define for_each_sd_topology(tl) \
1218 for (tl = sched_domain_topology; tl->mask; tl++)
1220 void set_sched_topology(struct sched_domain_topology_level
*tl
)
1222 if (WARN_ON_ONCE(sched_smp_initialized
))
1225 sched_domain_topology
= tl
;
1230 static const struct cpumask
*sd_numa_mask(int cpu
)
1232 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
1235 static void sched_numa_warn(const char *str
)
1237 static int done
= false;
1245 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
1247 for (i
= 0; i
< nr_node_ids
; i
++) {
1248 printk(KERN_WARNING
" ");
1249 for (j
= 0; j
< nr_node_ids
; j
++)
1250 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
1251 printk(KERN_CONT
"\n");
1253 printk(KERN_WARNING
"\n");
1256 bool find_numa_distance(int distance
)
1260 if (distance
== node_distance(0, 0))
1263 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
1264 if (sched_domains_numa_distance
[i
] == distance
)
1272 * A system can have three types of NUMA topology:
1273 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
1274 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
1275 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
1277 * The difference between a glueless mesh topology and a backplane
1278 * topology lies in whether communication between not directly
1279 * connected nodes goes through intermediary nodes (where programs
1280 * could run), or through backplane controllers. This affects
1281 * placement of programs.
1283 * The type of topology can be discerned with the following tests:
1284 * - If the maximum distance between any nodes is 1 hop, the system
1285 * is directly connected.
1286 * - If for two nodes A and B, located N > 1 hops away from each other,
1287 * there is an intermediary node C, which is < N hops away from both
1288 * nodes A and B, the system is a glueless mesh.
1290 static void init_numa_topology_type(void)
1294 n
= sched_max_numa_distance
;
1296 if (sched_domains_numa_levels
<= 1) {
1297 sched_numa_topology_type
= NUMA_DIRECT
;
1301 for_each_online_node(a
) {
1302 for_each_online_node(b
) {
1303 /* Find two nodes furthest removed from each other. */
1304 if (node_distance(a
, b
) < n
)
1307 /* Is there an intermediary node between a and b? */
1308 for_each_online_node(c
) {
1309 if (node_distance(a
, c
) < n
&&
1310 node_distance(b
, c
) < n
) {
1311 sched_numa_topology_type
=
1317 sched_numa_topology_type
= NUMA_BACKPLANE
;
1323 void sched_init_numa(void)
1325 int next_distance
, curr_distance
= node_distance(0, 0);
1326 struct sched_domain_topology_level
*tl
;
1330 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
1331 if (!sched_domains_numa_distance
)
1335 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
1336 * unique distances in the node_distance() table.
1338 * Assumes node_distance(0,j) includes all distances in
1339 * node_distance(i,j) in order to avoid cubic time.
1341 next_distance
= curr_distance
;
1342 for (i
= 0; i
< nr_node_ids
; i
++) {
1343 for (j
= 0; j
< nr_node_ids
; j
++) {
1344 for (k
= 0; k
< nr_node_ids
; k
++) {
1345 int distance
= node_distance(i
, k
);
1347 if (distance
> curr_distance
&&
1348 (distance
< next_distance
||
1349 next_distance
== curr_distance
))
1350 next_distance
= distance
;
1353 * While not a strong assumption it would be nice to know
1354 * about cases where if node A is connected to B, B is not
1355 * equally connected to A.
1357 if (sched_debug() && node_distance(k
, i
) != distance
)
1358 sched_numa_warn("Node-distance not symmetric");
1360 if (sched_debug() && i
&& !find_numa_distance(distance
))
1361 sched_numa_warn("Node-0 not representative");
1363 if (next_distance
!= curr_distance
) {
1364 sched_domains_numa_distance
[level
++] = next_distance
;
1365 sched_domains_numa_levels
= level
;
1366 curr_distance
= next_distance
;
1371 * In case of sched_debug() we verify the above assumption.
1381 * 'level' contains the number of unique distances, excluding the
1382 * identity distance node_distance(i,i).
1384 * The sched_domains_numa_distance[] array includes the actual distance
1389 * Here, we should temporarily reset sched_domains_numa_levels to 0.
1390 * If it fails to allocate memory for array sched_domains_numa_masks[][],
1391 * the array will contain less then 'level' members. This could be
1392 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
1393 * in other functions.
1395 * We reset it to 'level' at the end of this function.
1397 sched_domains_numa_levels
= 0;
1399 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
1400 if (!sched_domains_numa_masks
)
1404 * Now for each level, construct a mask per node which contains all
1405 * CPUs of nodes that are that many hops away from us.
1407 for (i
= 0; i
< level
; i
++) {
1408 sched_domains_numa_masks
[i
] =
1409 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
1410 if (!sched_domains_numa_masks
[i
])
1413 for (j
= 0; j
< nr_node_ids
; j
++) {
1414 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
1418 sched_domains_numa_masks
[i
][j
] = mask
;
1421 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
1424 cpumask_or(mask
, mask
, cpumask_of_node(k
));
1429 /* Compute default topology size */
1430 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
1432 tl
= kzalloc((i
+ level
+ 1) *
1433 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
1438 * Copy the default topology bits..
1440 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
1441 tl
[i
] = sched_domain_topology
[i
];
1444 * .. and append 'j' levels of NUMA goodness.
1446 for (j
= 0; j
< level
; i
++, j
++) {
1447 tl
[i
] = (struct sched_domain_topology_level
){
1448 .mask
= sd_numa_mask
,
1449 .sd_flags
= cpu_numa_flags
,
1450 .flags
= SDTL_OVERLAP
,
1456 sched_domain_topology
= tl
;
1458 sched_domains_numa_levels
= level
;
1459 sched_max_numa_distance
= sched_domains_numa_distance
[level
- 1];
1461 init_numa_topology_type();
1464 void sched_domains_numa_masks_set(unsigned int cpu
)
1466 int node
= cpu_to_node(cpu
);
1469 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
1470 for (j
= 0; j
< nr_node_ids
; j
++) {
1471 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
1472 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
1477 void sched_domains_numa_masks_clear(unsigned int cpu
)
1481 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
1482 for (j
= 0; j
< nr_node_ids
; j
++)
1483 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
1487 #endif /* CONFIG_NUMA */
1489 static int __sdt_alloc(const struct cpumask
*cpu_map
)
1491 struct sched_domain_topology_level
*tl
;
1494 for_each_sd_topology(tl
) {
1495 struct sd_data
*sdd
= &tl
->data
;
1497 sdd
->sd
= alloc_percpu(struct sched_domain
*);
1501 sdd
->sds
= alloc_percpu(struct sched_domain_shared
*);
1505 sdd
->sg
= alloc_percpu(struct sched_group
*);
1509 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
1513 for_each_cpu(j
, cpu_map
) {
1514 struct sched_domain
*sd
;
1515 struct sched_domain_shared
*sds
;
1516 struct sched_group
*sg
;
1517 struct sched_group_capacity
*sgc
;
1519 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
1520 GFP_KERNEL
, cpu_to_node(j
));
1524 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
1526 sds
= kzalloc_node(sizeof(struct sched_domain_shared
),
1527 GFP_KERNEL
, cpu_to_node(j
));
1531 *per_cpu_ptr(sdd
->sds
, j
) = sds
;
1533 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
1534 GFP_KERNEL
, cpu_to_node(j
));
1540 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
1542 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
1543 GFP_KERNEL
, cpu_to_node(j
));
1547 #ifdef CONFIG_SCHED_DEBUG
1551 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
1558 static void __sdt_free(const struct cpumask
*cpu_map
)
1560 struct sched_domain_topology_level
*tl
;
1563 for_each_sd_topology(tl
) {
1564 struct sd_data
*sdd
= &tl
->data
;
1566 for_each_cpu(j
, cpu_map
) {
1567 struct sched_domain
*sd
;
1570 sd
= *per_cpu_ptr(sdd
->sd
, j
);
1571 if (sd
&& (sd
->flags
& SD_OVERLAP
))
1572 free_sched_groups(sd
->groups
, 0);
1573 kfree(*per_cpu_ptr(sdd
->sd
, j
));
1577 kfree(*per_cpu_ptr(sdd
->sds
, j
));
1579 kfree(*per_cpu_ptr(sdd
->sg
, j
));
1581 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
1583 free_percpu(sdd
->sd
);
1585 free_percpu(sdd
->sds
);
1587 free_percpu(sdd
->sg
);
1589 free_percpu(sdd
->sgc
);
1594 static struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
1595 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
1596 struct sched_domain
*child
, int cpu
)
1598 struct sched_domain
*sd
= sd_init(tl
, cpu_map
, child
, cpu
);
1601 sd
->level
= child
->level
+ 1;
1602 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
1605 if (!cpumask_subset(sched_domain_span(child
),
1606 sched_domain_span(sd
))) {
1607 pr_err("BUG: arch topology borken\n");
1608 #ifdef CONFIG_SCHED_DEBUG
1609 pr_err(" the %s domain not a subset of the %s domain\n",
1610 child
->name
, sd
->name
);
1612 /* Fixup, ensure @sd has at least @child cpus. */
1613 cpumask_or(sched_domain_span(sd
),
1614 sched_domain_span(sd
),
1615 sched_domain_span(child
));
1619 set_domain_attribute(sd
, attr
);
1625 * Build sched domains for a given set of CPUs and attach the sched domains
1626 * to the individual CPUs
1629 build_sched_domains(const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
)
1631 enum s_alloc alloc_state
;
1632 struct sched_domain
*sd
;
1634 struct rq
*rq
= NULL
;
1635 int i
, ret
= -ENOMEM
;
1637 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
1638 if (alloc_state
!= sa_rootdomain
)
1641 /* Set up domains for CPUs specified by the cpu_map: */
1642 for_each_cpu(i
, cpu_map
) {
1643 struct sched_domain_topology_level
*tl
;
1646 for_each_sd_topology(tl
) {
1647 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
1648 if (tl
== sched_domain_topology
)
1649 *per_cpu_ptr(d
.sd
, i
) = sd
;
1650 if (tl
->flags
& SDTL_OVERLAP
)
1651 sd
->flags
|= SD_OVERLAP
;
1652 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
1657 /* Build the groups for the domains */
1658 for_each_cpu(i
, cpu_map
) {
1659 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
1660 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
1661 if (sd
->flags
& SD_OVERLAP
) {
1662 if (build_overlap_sched_groups(sd
, i
))
1665 if (build_sched_groups(sd
, i
))
1671 /* Calculate CPU capacity for physical packages and nodes */
1672 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
1673 if (!cpumask_test_cpu(i
, cpu_map
))
1676 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
1677 claim_allocations(i
, sd
);
1678 init_sched_groups_capacity(i
, sd
);
1682 /* Attach the domains */
1684 for_each_cpu(i
, cpu_map
) {
1686 sd
= *per_cpu_ptr(d
.sd
, i
);
1688 /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
1689 if (rq
->cpu_capacity_orig
> READ_ONCE(d
.rd
->max_cpu_capacity
))
1690 WRITE_ONCE(d
.rd
->max_cpu_capacity
, rq
->cpu_capacity_orig
);
1692 cpu_attach_domain(sd
, d
.rd
, i
);
1696 if (rq
&& sched_debug_enabled
) {
1697 pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
1698 cpumask_pr_args(cpu_map
), rq
->rd
->max_cpu_capacity
);
1703 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
1707 /* Current sched domains: */
1708 static cpumask_var_t
*doms_cur
;
1710 /* Number of sched domains in 'doms_cur': */
1711 static int ndoms_cur
;
1713 /* Attribues of custom domains in 'doms_cur' */
1714 static struct sched_domain_attr
*dattr_cur
;
1717 * Special case: If a kmalloc() of a doms_cur partition (array of
1718 * cpumask) fails, then fallback to a single sched domain,
1719 * as determined by the single cpumask fallback_doms.
1721 static cpumask_var_t fallback_doms
;
1724 * arch_update_cpu_topology lets virtualized architectures update the
1725 * CPU core maps. It is supposed to return 1 if the topology changed
1726 * or 0 if it stayed the same.
1728 int __weak
arch_update_cpu_topology(void)
1733 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
1736 cpumask_var_t
*doms
;
1738 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
1741 for (i
= 0; i
< ndoms
; i
++) {
1742 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
1743 free_sched_domains(doms
, i
);
1750 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
1753 for (i
= 0; i
< ndoms
; i
++)
1754 free_cpumask_var(doms
[i
]);
1759 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
1760 * For now this just excludes isolated CPUs, but could be used to
1761 * exclude other special cases in the future.
1763 int sched_init_domains(const struct cpumask
*cpu_map
)
1767 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_KERNEL
);
1768 zalloc_cpumask_var(&sched_domains_tmpmask2
, GFP_KERNEL
);
1769 zalloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
1771 arch_update_cpu_topology();
1773 doms_cur
= alloc_sched_domains(ndoms_cur
);
1775 doms_cur
= &fallback_doms
;
1776 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
1777 err
= build_sched_domains(doms_cur
[0], NULL
);
1778 register_sched_domain_sysctl();
1784 * Detach sched domains from a group of CPUs specified in cpu_map
1785 * These CPUs will now be attached to the NULL domain
1787 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
1792 for_each_cpu(i
, cpu_map
)
1793 cpu_attach_domain(NULL
, &def_root_domain
, i
);
1797 /* handle null as "default" */
1798 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
1799 struct sched_domain_attr
*new, int idx_new
)
1801 struct sched_domain_attr tmp
;
1808 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
1809 new ? (new + idx_new
) : &tmp
,
1810 sizeof(struct sched_domain_attr
));
1814 * Partition sched domains as specified by the 'ndoms_new'
1815 * cpumasks in the array doms_new[] of cpumasks. This compares
1816 * doms_new[] to the current sched domain partitioning, doms_cur[].
1817 * It destroys each deleted domain and builds each new domain.
1819 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
1820 * The masks don't intersect (don't overlap.) We should setup one
1821 * sched domain for each mask. CPUs not in any of the cpumasks will
1822 * not be load balanced. If the same cpumask appears both in the
1823 * current 'doms_cur' domains and in the new 'doms_new', we can leave
1826 * The passed in 'doms_new' should be allocated using
1827 * alloc_sched_domains. This routine takes ownership of it and will
1828 * free_sched_domains it when done with it. If the caller failed the
1829 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
1830 * and partition_sched_domains() will fallback to the single partition
1831 * 'fallback_doms', it also forces the domains to be rebuilt.
1833 * If doms_new == NULL it will be replaced with cpu_online_mask.
1834 * ndoms_new == 0 is a special case for destroying existing domains,
1835 * and it will not create the default domain.
1837 * Call with hotplug lock held
1839 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
1840 struct sched_domain_attr
*dattr_new
)
1845 mutex_lock(&sched_domains_mutex
);
1847 /* Always unregister in case we don't destroy any domains: */
1848 unregister_sched_domain_sysctl();
1850 /* Let the architecture update CPU core mappings: */
1851 new_topology
= arch_update_cpu_topology();
1854 WARN_ON_ONCE(dattr_new
);
1856 doms_new
= alloc_sched_domains(1);
1859 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
1865 /* Destroy deleted domains: */
1866 for (i
= 0; i
< ndoms_cur
; i
++) {
1867 for (j
= 0; j
< n
&& !new_topology
; j
++) {
1868 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
1869 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
1872 /* No match - a current sched domain not in new doms_new[] */
1873 detach_destroy_domains(doms_cur
[i
]);
1881 doms_new
= &fallback_doms
;
1882 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
1885 /* Build new domains: */
1886 for (i
= 0; i
< ndoms_new
; i
++) {
1887 for (j
= 0; j
< n
&& !new_topology
; j
++) {
1888 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
1889 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
1892 /* No match - add a new doms_new */
1893 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
1898 /* Remember the new sched domains: */
1899 if (doms_cur
!= &fallback_doms
)
1900 free_sched_domains(doms_cur
, ndoms_cur
);
1903 doms_cur
= doms_new
;
1904 dattr_cur
= dattr_new
;
1905 ndoms_cur
= ndoms_new
;
1907 register_sched_domain_sysctl();
1909 mutex_unlock(&sched_domains_mutex
);