| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Ingo Molnar | 5772 | 55.58% | 4 | 2.41% |
| Quentin Perret | 760 | 7.32% | 6 | 3.61% |
| Valentin Schneider | 625 | 6.02% | 16 | 9.64% |
| Peter Zijlstra | 456 | 4.39% | 31 | 18.67% |
| Beata Michalska | 440 | 4.24% | 1 | 0.60% |
| Huang Ying | 392 | 3.77% | 1 | 0.60% |
| Yury Norov | 375 | 3.61% | 6 | 3.61% |
| Shrikanth Hegde | 261 | 2.51% | 1 | 0.60% |
| Barry Song | 194 | 1.87% | 5 | 3.01% |
| Mel Gorman | 188 | 1.81% | 2 | 1.20% |
| Lauro Ramos Venancio | 174 | 1.68% | 3 | 1.81% |
| Steven Rostedt | 75 | 0.72% | 2 | 1.20% |
| Morten Rasmussen | 75 | 0.72% | 6 | 3.61% |
| Tim Chen | 65 | 0.63% | 2 | 1.20% |
| Vincent Guittot | 56 | 0.54% | 6 | 3.61% |
| Ricardo Neri | 52 | 0.50% | 1 | 0.60% |
| Zhen Ni | 51 | 0.49% | 1 | 0.60% |
| Mathieu J. Poirier | 42 | 0.40% | 2 | 1.20% |
| Wanpeng Li | 40 | 0.39% | 2 | 1.20% |
| Linus Torvalds (pre-git) | 34 | 0.33% | 6 | 3.61% |
| Suravee Suthikulpanit | 29 | 0.28% | 1 | 0.60% |
| Frédéric Weisbecker | 20 | 0.19% | 3 | 1.81% |
| Shu Wang | 18 | 0.17% | 1 | 0.60% |
| Joel A Fernandes | 15 | 0.14% | 1 | 0.60% |
| Suresh B. Siddha | 15 | 0.14% | 1 | 0.60% |
| Eric Dumazet | 11 | 0.11% | 1 | 0.60% |
| Ionela Voinescu | 11 | 0.11% | 2 | 1.20% |
| Thomas Gleixner | 10 | 0.10% | 2 | 1.20% |
| Hao Jia | 9 | 0.09% | 1 | 0.60% |
| Rafael J. Wysocki | 8 | 0.08% | 2 | 1.20% |
| Peng Liu | 6 | 0.06% | 1 | 0.60% |
| Paul Turner | 6 | 0.06% | 1 | 0.60% |
| Art Haas | 6 | 0.06% | 1 | 0.60% |
| Dario Faggioli | 6 | 0.06% | 1 | 0.60% |
| Gustavo A. R. Silva | 6 | 0.06% | 1 | 0.60% |
| Tang Chen | 6 | 0.06% | 1 | 0.60% |
| Hideaki Yoshifuji / 吉藤英明 | 5 | 0.05% | 1 | 0.60% |
| Heiko Carstens | 5 | 0.05% | 1 | 0.60% |
| Dietmar Eggemann | 5 | 0.05% | 2 | 1.20% |
| Chen Yu | 4 | 0.04% | 1 | 0.60% |
| K Prateek Nayak | 3 | 0.03% | 1 | 0.60% |
| Nikhil P Rao | 3 | 0.03% | 1 | 0.60% |
| Kees Cook | 3 | 0.03% | 1 | 0.60% |
| Eric W. Biedermann | 3 | 0.03% | 3 | 1.81% |
| Sebastian Andrzej Siewior | 3 | 0.03% | 1 | 0.60% |
| Alexei Starovoitov | 3 | 0.03% | 1 | 0.60% |
| Matteo Croce | 2 | 0.02% | 1 | 0.60% |
| Milton D. Miller II | 2 | 0.02% | 1 | 0.60% |
| Lukasz Luba | 2 | 0.02% | 1 | 0.60% |
| Juri Lelli | 2 | 0.02% | 2 | 1.20% |
| Yi Wang | 2 | 0.02% | 1 | 0.60% |
| Viresh Kumar | 2 | 0.02% | 2 | 1.20% |
| Paul E. McKenney | 2 | 0.02% | 1 | 0.60% |
| Srivatsa Vaddagiri | 2 | 0.02% | 1 | 0.60% |
| zhong jiang | 2 | 0.02% | 1 | 0.60% |
| Peter Williams | 2 | 0.02% | 1 | 0.60% |
| Linus Torvalds | 2 | 0.02% | 1 | 0.60% |
| Alexey Dobriyan | 2 | 0.02% | 1 | 0.60% |
| Tom Rix | 2 | 0.02% | 1 | 0.60% |
| Bing Huang | 2 | 0.02% | 2 | 1.20% |
| Pierre Gondois | 1 | 0.01% | 1 | 0.60% |
| Mike Travis | 1 | 0.01% | 1 | 0.60% |
| Srikar Dronamraju | 1 | 0.01% | 1 | 0.60% |
| Luc Van Oostenryck | 1 | 0.01% | 1 | 0.60% |
| Christoph Hellwig | 1 | 0.01% | 1 | 0.60% |
| Miaohe Lin | 1 | 0.01% | 1 | 0.60% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 0.60% |
| Octavian Purdila | 1 | 0.01% | 1 | 0.60% |
| Dmitry Torokhov | 1 | 0.01% | 1 | 0.60% |
| Nico Pitre | 1 | 0.01% | 1 | 0.60% |
| Matt Fleming | 1 | 0.01% | 1 | 0.60% |
| Total | 10385 | 166 |
// SPDX-License-Identifier: GPL-2.0 /* * Scheduler topology setup/handling methods */ #include <linux/bsearch.h> DEFINE_MUTEX(sched_domains_mutex); /* Protected by sched_domains_mutex: */ static cpumask_var_t sched_domains_tmpmask; static cpumask_var_t sched_domains_tmpmask2; #ifdef CONFIG_SCHED_DEBUG static int __init sched_debug_setup(char *str) { sched_debug_verbose = true; return 0; } early_param("sched_verbose", sched_debug_setup); static inline bool sched_debug(void) { return sched_debug_verbose; } #define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name }, const struct sd_flag_debug sd_flag_debug[] = { #include <linux/sched/sd_flags.h> }; #undef SD_FLAG static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, struct cpumask *groupmask) { struct sched_group *group = sd->groups; unsigned long flags = sd->flags; unsigned int idx; cpumask_clear(groupmask); printk(KERN_DEBUG "%*s domain-%d: ", level, "", level); printk(KERN_CONT "span=%*pbl level=%s\n", cpumask_pr_args(sched_domain_span(sd)), sd->name); if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu); } if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) { printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu); } for_each_set_bit(idx, &flags, __SD_FLAG_CNT) { unsigned int flag = BIT(idx); unsigned int meta_flags = sd_flag_debug[idx].meta_flags; if ((meta_flags & SDF_SHARED_CHILD) && sd->child && !(sd->child->flags & flag)) printk(KERN_ERR "ERROR: flag %s set here but not in child\n", sd_flag_debug[idx].name); if ((meta_flags & SDF_SHARED_PARENT) && sd->parent && !(sd->parent->flags & flag)) printk(KERN_ERR "ERROR: flag %s set here but not in parent\n", sd_flag_debug[idx].name); } printk(KERN_DEBUG "%*s groups:", level + 1, ""); do { if (!group) { printk("\n"); printk(KERN_ERR "ERROR: group is NULL\n"); break; } if (cpumask_empty(sched_group_span(group))) { printk(KERN_CONT "\n"); printk(KERN_ERR "ERROR: empty group\n"); break; } if (!(sd->flags & SD_OVERLAP) && cpumask_intersects(groupmask, sched_group_span(group))) { printk(KERN_CONT "\n"); printk(KERN_ERR "ERROR: repeated CPUs\n"); break; } cpumask_or(groupmask, groupmask, sched_group_span(group)); printk(KERN_CONT " %d:{ span=%*pbl", group->sgc->id, cpumask_pr_args(sched_group_span(group))); if ((sd->flags & SD_OVERLAP) && !cpumask_equal(group_balance_mask(group), sched_group_span(group))) { printk(KERN_CONT " mask=%*pbl", cpumask_pr_args(group_balance_mask(group))); } if (group->sgc->capacity != SCHED_CAPACITY_SCALE) printk(KERN_CONT " cap=%lu", group->sgc->capacity); if (group == sd->groups && sd->child && !cpumask_equal(sched_domain_span(sd->child), sched_group_span(group))) { printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n"); } printk(KERN_CONT " }"); group = group->next; if (group != sd->groups) printk(KERN_CONT ","); } while (group != sd->groups); printk(KERN_CONT "\n"); if (!cpumask_equal(sched_domain_span(sd), groupmask)) printk(KERN_ERR "ERROR: groups don't span domain->span\n"); if (sd->parent && !cpumask_subset(groupmask, sched_domain_span(sd->parent))) printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n"); return 0; } static void sched_domain_debug(struct sched_domain *sd, int cpu) { int level = 0; if (!sched_debug_verbose) return; if (!sd) { printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); return; } printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu); for (;;) { if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) break; level++; sd = sd->parent; if (!sd) break; } } #else /* !CONFIG_SCHED_DEBUG */ # define sched_debug_verbose 0 # define sched_domain_debug(sd, cpu) do { } while (0) static inline bool sched_debug(void) { return false; } #endif /* CONFIG_SCHED_DEBUG */ /* Generate a mask of SD flags with the SDF_NEEDS_GROUPS metaflag */ #define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_NEEDS_GROUPS)) | static const unsigned int SD_DEGENERATE_GROUPS_MASK = #include <linux/sched/sd_flags.h> 0; #undef SD_FLAG static int sd_degenerate(struct sched_domain *sd) { if (cpumask_weight(sched_domain_span(sd)) == 1) return 1; /* Following flags need at least 2 groups */ if ((sd->flags & SD_DEGENERATE_GROUPS_MASK) && (sd->groups != sd->groups->next)) return 0; /* Following flags don't use groups */ if (sd->flags & (SD_WAKE_AFFINE)) return 0; return 1; } static int sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) { unsigned long cflags = sd->flags, pflags = parent->flags; if (sd_degenerate(parent)) return 1; if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) return 0; /* Flags needing groups don't count if only 1 group in parent */ if (parent->groups == parent->groups->next) pflags &= ~SD_DEGENERATE_GROUPS_MASK; if (~cflags & pflags) return 0; return 1; } #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) DEFINE_STATIC_KEY_FALSE(sched_energy_present); static unsigned int sysctl_sched_energy_aware = 1; static DEFINE_MUTEX(sched_energy_mutex); static bool sched_energy_update; static bool sched_is_eas_possible(const struct cpumask *cpu_mask) { bool any_asym_capacity = false; struct cpufreq_policy *policy; struct cpufreq_governor *gov; int i; /* EAS is enabled for asymmetric CPU capacity topologies. */ for_each_cpu(i, cpu_mask) { if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, i))) { any_asym_capacity = true; break; } } if (!any_asym_capacity) { if (sched_debug()) { pr_info("rd %*pbl: Checking EAS, CPUs do not have asymmetric capacities\n", cpumask_pr_args(cpu_mask)); } return false; } /* EAS definitely does *not* handle SMT */ if (sched_smt_active()) { if (sched_debug()) { pr_info("rd %*pbl: Checking EAS, SMT is not supported\n", cpumask_pr_args(cpu_mask)); } return false; } if (!arch_scale_freq_invariant()) { if (sched_debug()) { pr_info("rd %*pbl: Checking EAS: frequency-invariant load tracking not yet supported", cpumask_pr_args(cpu_mask)); } return false; } /* Do not attempt EAS if schedutil is not being used. */ for_each_cpu(i, cpu_mask) { policy = cpufreq_cpu_get(i); if (!policy) { if (sched_debug()) { pr_info("rd %*pbl: Checking EAS, cpufreq policy not set for CPU: %d", cpumask_pr_args(cpu_mask), i); } return false; } gov = policy->governor; cpufreq_cpu_put(policy); if (gov != &schedutil_gov) { if (sched_debug()) { pr_info("rd %*pbl: Checking EAS, schedutil is mandatory\n", cpumask_pr_args(cpu_mask)); } return false; } } return true; } void rebuild_sched_domains_energy(void) { mutex_lock(&sched_energy_mutex); sched_energy_update = true; rebuild_sched_domains(); sched_energy_update = false; mutex_unlock(&sched_energy_mutex); } #ifdef CONFIG_PROC_SYSCTL static int sched_energy_aware_handler(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { int ret, state; if (write && !capable(CAP_SYS_ADMIN)) return -EPERM; if (!sched_is_eas_possible(cpu_active_mask)) { if (write) { return -EOPNOTSUPP; } else { *lenp = 0; return 0; } } ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (!ret && write) { state = static_branch_unlikely(&sched_energy_present); if (state != sysctl_sched_energy_aware) rebuild_sched_domains_energy(); } return ret; } static struct ctl_table sched_energy_aware_sysctls[] = { { .procname = "sched_energy_aware", .data = &sysctl_sched_energy_aware, .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = sched_energy_aware_handler, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, {} }; static int __init sched_energy_aware_sysctl_init(void) { register_sysctl_init("kernel", sched_energy_aware_sysctls); return 0; } late_initcall(sched_energy_aware_sysctl_init); #endif static void free_pd(struct perf_domain *pd) { struct perf_domain *tmp; while (pd) { tmp = pd->next; kfree(pd); pd = tmp; } } static struct perf_domain *find_pd(struct perf_domain *pd, int cpu) { while (pd) { if (cpumask_test_cpu(cpu, perf_domain_span(pd))) return pd; pd = pd->next; } return NULL; } static struct perf_domain *pd_init(int cpu) { struct em_perf_domain *obj = em_cpu_get(cpu); struct perf_domain *pd; if (!obj) { if (sched_debug()) pr_info("%s: no EM found for CPU%d\n", __func__, cpu); return NULL; } pd = kzalloc(sizeof(*pd), GFP_KERNEL); if (!pd) return NULL; pd->em_pd = obj; return pd; } static void perf_domain_debug(const struct cpumask *cpu_map, struct perf_domain *pd) { if (!sched_debug() || !pd) return; printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map)); while (pd) { printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_pstate=%d }", cpumask_first(perf_domain_span(pd)), cpumask_pr_args(perf_domain_span(pd)), em_pd_nr_perf_states(pd->em_pd)); pd = pd->next; } printk(KERN_CONT "\n"); } static void destroy_perf_domain_rcu(struct rcu_head *rp) { struct perf_domain *pd; pd = container_of(rp, struct perf_domain, rcu); free_pd(pd); } static void sched_energy_set(bool has_eas) { if (!has_eas && static_branch_unlikely(&sched_energy_present)) { if (sched_debug()) pr_info("%s: stopping EAS\n", __func__); static_branch_disable_cpuslocked(&sched_energy_present); } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) { if (sched_debug()) pr_info("%s: starting EAS\n", __func__); static_branch_enable_cpuslocked(&sched_energy_present); } } /* * EAS can be used on a root domain if it meets all the following conditions: * 1. an Energy Model (EM) is available; * 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy. * 3. no SMT is detected. * 4. schedutil is driving the frequency of all CPUs of the rd; * 5. frequency invariance support is present; */ static bool build_perf_domains(const struct cpumask *cpu_map) { int i; struct perf_domain *pd = NULL, *tmp; int cpu = cpumask_first(cpu_map); struct root_domain *rd = cpu_rq(cpu)->rd; if (!sysctl_sched_energy_aware) goto free; if (!sched_is_eas_possible(cpu_map)) goto free; for_each_cpu(i, cpu_map) { /* Skip already covered CPUs. */ if (find_pd(pd, i)) continue; /* Create the new pd and add it to the local list. */ tmp = pd_init(i); if (!tmp) goto free; tmp->next = pd; pd = tmp; } perf_domain_debug(cpu_map, pd); /* Attach the new list of performance domains to the root domain. */ tmp = rd->pd; rcu_assign_pointer(rd->pd, pd); if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); return !!pd; free: free_pd(pd); tmp = rd->pd; rcu_assign_pointer(rd->pd, NULL); if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); return false; } #else static void free_pd(struct perf_domain *pd) { } #endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/ static void free_rootdomain(struct rcu_head *rcu) { struct root_domain *rd = container_of(rcu, struct root_domain, rcu); cpupri_cleanup(&rd->cpupri); cpudl_cleanup(&rd->cpudl); free_cpumask_var(rd->dlo_mask); free_cpumask_var(rd->rto_mask); free_cpumask_var(rd->online); free_cpumask_var(rd->span); free_pd(rd->pd); kfree(rd); } void rq_attach_root(struct rq *rq, struct root_domain *rd) { struct root_domain *old_rd = NULL; struct rq_flags rf; rq_lock_irqsave(rq, &rf); if (rq->rd) { old_rd = rq->rd; if (cpumask_test_cpu(rq->cpu, old_rd->online)) set_rq_offline(rq); cpumask_clear_cpu(rq->cpu, old_rd->span); /* * If we dont want to free the old_rd yet then * set old_rd to NULL to skip the freeing later * in this function: */ if (!atomic_dec_and_test(&old_rd->refcount)) old_rd = NULL; } atomic_inc(&rd->refcount); rq->rd = rd; cpumask_set_cpu(rq->cpu, rd->span); if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) set_rq_online(rq); rq_unlock_irqrestore(rq, &rf); if (old_rd) call_rcu(&old_rd->rcu, free_rootdomain); } void sched_get_rd(struct root_domain *rd) { atomic_inc(&rd->refcount); } void sched_put_rd(struct root_domain *rd) { if (!atomic_dec_and_test(&rd->refcount)) return; call_rcu(&rd->rcu, free_rootdomain); } static int init_rootdomain(struct root_domain *rd) { if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) goto out; if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) goto free_span; if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) goto free_online; if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) goto free_dlo_mask; #ifdef HAVE_RT_PUSH_IPI rd->rto_cpu = -1; raw_spin_lock_init(&rd->rto_lock); rd->rto_push_work = IRQ_WORK_INIT_HARD(rto_push_irq_work_func); #endif rd->visit_gen = 0; init_dl_bw(&rd->dl_bw); if (cpudl_init(&rd->cpudl) != 0) goto free_rto_mask; if (cpupri_init(&rd->cpupri) != 0) goto free_cpudl; return 0; free_cpudl: cpudl_cleanup(&rd->cpudl); free_rto_mask: free_cpumask_var(rd->rto_mask); free_dlo_mask: free_cpumask_var(rd->dlo_mask); free_online: free_cpumask_var(rd->online); free_span: free_cpumask_var(rd->span); out: return -ENOMEM; } /* * By default the system creates a single root-domain with all CPUs as * members (mimicking the global state we have today). */ struct root_domain def_root_domain; void __init init_defrootdomain(void) { init_rootdomain(&def_root_domain); atomic_set(&def_root_domain.refcount, 1); } static struct root_domain *alloc_rootdomain(void) { struct root_domain *rd; rd = kzalloc(sizeof(*rd), GFP_KERNEL); if (!rd) return NULL; if (init_rootdomain(rd) != 0) { kfree(rd); return NULL; } return rd; } static void free_sched_groups(struct sched_group *sg, int free_sgc) { struct sched_group *tmp, *first; if (!sg) return; first = sg; do { tmp = sg->next; if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) kfree(sg->sgc); if (atomic_dec_and_test(&sg->ref)) kfree(sg); sg = tmp; } while (sg != first); } static void destroy_sched_domain(struct sched_domain *sd) { /* * A normal sched domain may have multiple group references, an * overlapping domain, having private groups, only one. Iterate, * dropping group/capacity references, freeing where none remain. */ free_sched_groups(sd->groups, 1); if (sd->shared && atomic_dec_and_test(&sd->shared->ref)) kfree(sd->shared); kfree(sd); } static void destroy_sched_domains_rcu(struct rcu_head *rcu) { struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); while (sd) { struct sched_domain *parent = sd->parent; destroy_sched_domain(sd); sd = parent; } } static void destroy_sched_domains(struct sched_domain *sd) { if (sd) call_rcu(&sd->rcu, destroy_sched_domains_rcu); } /* * Keep a special pointer to the highest sched_domain that has * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this * allows us to avoid some pointer chasing select_idle_sibling(). * * Also keep a unique ID per domain (we use the first CPU number in * the cpumask of the domain), this allows us to quickly tell if * two CPUs are in the same cache domain, see cpus_share_cache(). */ DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc); DEFINE_PER_CPU(int, sd_llc_size); DEFINE_PER_CPU(int, sd_llc_id); DEFINE_PER_CPU(int, sd_share_id); DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity); DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity); DEFINE_STATIC_KEY_FALSE(sched_cluster_active); static void update_top_cache_domain(int cpu) { struct sched_domain_shared *sds = NULL; struct sched_domain *sd; int id = cpu; int size = 1; sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); if (sd) { id = cpumask_first(sched_domain_span(sd)); size = cpumask_weight(sched_domain_span(sd)); sds = sd->shared; } rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); per_cpu(sd_llc_size, cpu) = size; per_cpu(sd_llc_id, cpu) = id; rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds); sd = lowest_flag_domain(cpu, SD_CLUSTER); if (sd) id = cpumask_first(sched_domain_span(sd)); /* * This assignment should be placed after the sd_llc_id as * we want this id equals to cluster id on cluster machines * but equals to LLC id on non-Cluster machines. */ per_cpu(sd_share_id, cpu) = id; sd = lowest_flag_domain(cpu, SD_NUMA); rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); sd = highest_flag_domain(cpu, SD_ASYM_PACKING); rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd); sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY_FULL); rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd); } /* * Attach the domain 'sd' to 'cpu' as its base domain. Callers must * hold the hotplug lock. */ static void cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) { struct rq *rq = cpu_rq(cpu); struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) { parent->parent->child = tmp; parent->parent->groups->flags = tmp->flags; } /* * Transfer SD_PREFER_SIBLING down in case of a * degenerate parent; the spans match for this * so the property transfers. */ if (parent->flags & SD_PREFER_SIBLING) tmp->flags |= SD_PREFER_SIBLING; destroy_sched_domain(parent); } else tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { tmp = sd; sd = sd->parent; destroy_sched_domain(tmp); if (sd) { struct sched_group *sg = sd->groups; /* * sched groups hold the flags of the child sched * domain for convenience. Clear such flags since * the child is being destroyed. */ do { sg->flags = 0; } while (sg != sd->groups); sd->child = NULL; } } sched_domain_debug(sd, cpu); rq_attach_root(rq, rd); tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); dirty_sched_domain_sysctl(cpu); destroy_sched_domains(tmp); update_top_cache_domain(cpu); } struct s_data { struct sched_domain * __percpu *sd; struct root_domain *rd; }; enum s_alloc { sa_rootdomain, sa_sd, sa_sd_storage, sa_none, }; /* * Return the canonical balance CPU for this group, this is the first CPU * of this group that's also in the balance mask. * * The balance mask are all those CPUs that could actually end up at this * group. See build_balance_mask(). * * Also see should_we_balance(). */ int group_balance_cpu(struct sched_group *sg) { return cpumask_first(group_balance_mask(sg)); } /* * NUMA topology (first read the regular topology blurb below) * * Given a node-distance table, for example: * * node 0 1 2 3 * 0: 10 20 30 20 * 1: 20 10 20 30 * 2: 30 20 10 20 * 3: 20 30 20 10 * * which represents a 4 node ring topology like: * * 0 ----- 1 * | | * | | * | | * 3 ----- 2 * * We want to construct domains and groups to represent this. The way we go * about doing this is to build the domains on 'hops'. For each NUMA level we * construct the mask of all nodes reachable in @level hops. * * For the above NUMA topology that gives 3 levels: * * NUMA-2 0-3 0-3 0-3 0-3 * groups: {0-1,3},{1-3} {0-2},{0,2-3} {1-3},{0-1,3} {0,2-3},{0-2} * * NUMA-1 0-1,3 0-2 1-3 0,2-3 * groups: {0},{1},{3} {0},{1},{2} {1},{2},{3} {0},{2},{3} * * NUMA-0 0 1 2 3 * * * As can be seen; things don't nicely line up as with the regular topology. * When we iterate a domain in child domain chunks some nodes can be * represented multiple times -- hence the "overlap" naming for this part of * the topology. * * In order to minimize this overlap, we only build enough groups to cover the * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3. * * Because: * * - the first group of each domain is its child domain; this * gets us the first 0-1,3 * - the only uncovered node is 2, who's child domain is 1-3. * * However, because of the overlap, computing a unique CPU for each group is * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both * groups include the CPUs of Node-0, while those CPUs would not in fact ever * end up at those groups (they would end up in group: 0-1,3). * * To correct this we have to introduce the group balance mask. This mask * will contain those CPUs in the group that can reach this group given the * (child) domain tree. * * With this we can once again compute balance_cpu and sched_group_capacity * relations. * * XXX include words on how balance_cpu is unique and therefore can be * used for sched_group_capacity links. * * * Another 'interesting' topology is: * * node 0 1 2 3 * 0: 10 20 20 30 * 1: 20 10 20 20 * 2: 20 20 10 20 * 3: 30 20 20 10 * * Which looks a little like: * * 0 ----- 1 * | / | * | / | * | / | * 2 ----- 3 * * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3 * are not. * * This leads to a few particularly weird cases where the sched_domain's are * not of the same number for each CPU. Consider: * * NUMA-2 0-3 0-3 * groups: {0-2},{1-3} {1-3},{0-2} * * NUMA-1 0-2 0-3 0-3 1-3 * * NUMA-0 0 1 2 3 * */ /* * Build the balance mask; it contains only those CPUs that can arrive at this * group and should be considered to continue balancing. * * We do this during the group creation pass, therefore the group information * isn't complete yet, however since each group represents a (child) domain we * can fully construct this using the sched_domain bits (which are already * complete). */ static void build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask) { const struct cpumask *sg_span = sched_group_span(sg); struct sd_data *sdd = sd->private; struct sched_domain *sibling; int i; cpumask_clear(mask); for_each_cpu(i, sg_span) { sibling = *per_cpu_ptr(sdd->sd, i); /* * Can happen in the asymmetric case, where these siblings are * unused. The mask will not be empty because those CPUs that * do have the top domain _should_ span the domain. */ if (!sibling->child) continue; /* If we would not end up here, we can't continue from here */ if (!cpumask_equal(sg_span, sched_domain_span(sibling->child))) continue; cpumask_set_cpu(i, mask); } /* We must not have empty masks here */ WARN_ON_ONCE(cpumask_empty(mask)); } /* * XXX: This creates per-node group entries; since the load-balancer will * immediately access remote memory to construct this group's load-balance * statistics having the groups node local is of dubious benefit. */ static struct sched_group * build_group_from_child_sched_domain(struct sched_domain *sd, int cpu) { struct sched_group *sg; struct cpumask *sg_span; sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), GFP_KERNEL, cpu_to_node(cpu)); if (!sg) return NULL; sg_span = sched_group_span(sg); if (sd->child) { cpumask_copy(sg_span, sched_domain_span(sd->child)); sg->flags = sd->child->flags; } else { cpumask_copy(sg_span, sched_domain_span(sd)); } atomic_inc(&sg->ref); return sg; } static void init_overlap_sched_group(struct sched_domain *sd, struct sched_group *sg) { struct cpumask *mask = sched_domains_tmpmask2; struct sd_data *sdd = sd->private; struct cpumask *sg_span; int cpu; build_balance_mask(sd, sg, mask); cpu = cpumask_first(mask); sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); if (atomic_inc_return(&sg->sgc->ref) == 1) cpumask_copy(group_balance_mask(sg), mask); else WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask)); /* * Initialize sgc->capacity such that even if we mess up the * domains and no possible iteration will get us here, we won't * die on a /0 trap. */ sg_span = sched_group_span(sg); sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; } static struct sched_domain * find_descended_sibling(struct sched_domain *sd, struct sched_domain *sibling) { /* * The proper descendant would be the one whose child won't span out * of sd */ while (sibling->child && !cpumask_subset(sched_domain_span(sibling->child), sched_domain_span(sd))) sibling = sibling->child; /* * As we are referencing sgc across different topology level, we need * to go down to skip those sched_domains which don't contribute to * scheduling because they will be degenerated in cpu_attach_domain */ while (sibling->child && cpumask_equal(sched_domain_span(sibling->child), sched_domain_span(sibling))) sibling = sibling->child; return sibling; } static int build_overlap_sched_groups(struct sched_domain *sd, int cpu) { struct sched_group *first = NULL, *last = NULL, *sg; const struct cpumask *span = sched_domain_span(sd); struct cpumask *covered = sched_domains_tmpmask; struct sd_data *sdd = sd->private; struct sched_domain *sibling; int i; cpumask_clear(covered); for_each_cpu_wrap(i, span, cpu) { struct cpumask *sg_span; if (cpumask_test_cpu(i, covered)) continue; sibling = *per_cpu_ptr(sdd->sd, i); /* * Asymmetric node setups can result in situations where the * domain tree is of unequal depth, make sure to skip domains * that already cover the entire range. * * In that case build_sched_domains() will have terminated the * iteration early and our sibling sd spans will be empty. * Domains should always include the CPU they're built on, so * check that. */ if (!cpumask_test_cpu(i, sched_domain_span(sibling))) continue; /* * Usually we build sched_group by sibling's child sched_domain * But for machines whose NUMA diameter are 3 or above, we move * to build sched_group by sibling's proper descendant's child * domain because sibling's child sched_domain will span out of * the sched_domain being built as below. * * Smallest diameter=3 topology is: * * node 0 1 2 3 * 0: 10 20 30 40 * 1: 20 10 20 30 * 2: 30 20 10 20 * 3: 40 30 20 10 * * 0 --- 1 --- 2 --- 3 * * NUMA-3 0-3 N/A N/A 0-3 * groups: {0-2},{1-3} {1-3},{0-2} * * NUMA-2 0-2 0-3 0-3 1-3 * groups: {0-1},{1-3} {0-2},{2-3} {1-3},{0-1} {2-3},{0-2} * * NUMA-1 0-1 0-2 1-3 2-3 * groups: {0},{1} {1},{2},{0} {2},{3},{1} {3},{2} * * NUMA-0 0 1 2 3 * * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the * group span isn't a subset of the domain span. */ if (sibling->child && !cpumask_subset(sched_domain_span(sibling->child), span)) sibling = find_descended_sibling(sd, sibling); sg = build_group_from_child_sched_domain(sibling, cpu); if (!sg) goto fail; sg_span = sched_group_span(sg); cpumask_or(covered, covered, sg_span); init_overlap_sched_group(sibling, sg); if (!first) first = sg; if (last) last->next = sg; last = sg; last->next = first; } sd->groups = first; return 0; fail: free_sched_groups(first, 0); return -ENOMEM; } /* * Package topology (also see the load-balance blurb in fair.c) * * The scheduler builds a tree structure to represent a number of important * topology features. By default (default_topology[]) these include: * * - Simultaneous multithreading (SMT) * - Multi-Core Cache (MC) * - Package (PKG) * * Where the last one more or less denotes everything up to a NUMA node. * * The tree consists of 3 primary data structures: * * sched_domain -> sched_group -> sched_group_capacity * ^ ^ ^ ^ * `-' `-' * * The sched_domains are per-CPU and have a two way link (parent & child) and * denote the ever growing mask of CPUs belonging to that level of topology. * * Each sched_domain has a circular (double) linked list of sched_group's, each * denoting the domains of the level below (or individual CPUs in case of the * first domain level). The sched_group linked by a sched_domain includes the * CPU of that sched_domain [*]. * * Take for instance a 2 threaded, 2 core, 2 cache cluster part: * * CPU 0 1 2 3 4 5 6 7 * * PKG [ ] * MC [ ] [ ] * SMT [ ] [ ] [ ] [ ] * * - or - * * PKG 0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7 * MC 0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7 * SMT 0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7 * * CPU 0 1 2 3 4 5 6 7 * * One way to think about it is: sched_domain moves you up and down among these * topology levels, while sched_group moves you sideways through it, at child * domain granularity. * * sched_group_capacity ensures each unique sched_group has shared storage. * * There are two related construction problems, both require a CPU that * uniquely identify each group (for a given domain): * * - The first is the balance_cpu (see should_we_balance() and the * load-balance blub in fair.c); for each group we only want 1 CPU to * continue balancing at a higher domain. * * - The second is the sched_group_capacity; we want all identical groups * to share a single sched_group_capacity. * * Since these topologies are exclusive by construction. That is, its * impossible for an SMT thread to belong to multiple cores, and cores to * be part of multiple caches. There is a very clear and unique location * for each CPU in the hierarchy. * * Therefore computing a unique CPU for each group is trivial (the iteration * mask is redundant and set all 1s; all CPUs in a group will end up at _that_ * group), we can simply pick the first CPU in each group. * * * [*] in other words, the first group of each domain is its child domain. */ static struct sched_group *get_group(int cpu, struct sd_data *sdd) { struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); struct sched_domain *child = sd->child; struct sched_group *sg; bool already_visited; if (child) cpu = cpumask_first(sched_domain_span(child)); sg = *per_cpu_ptr(sdd->sg, cpu); sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); /* Increase refcounts for claim_allocations: */ already_visited = atomic_inc_return(&sg->ref) > 1; /* sgc visits should follow a similar trend as sg */ WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1)); /* If we have already visited that group, it's already initialized. */ if (already_visited) return sg; if (child) { cpumask_copy(sched_group_span(sg), sched_domain_span(child)); cpumask_copy(group_balance_mask(sg), sched_group_span(sg)); sg->flags = child->flags; } else { cpumask_set_cpu(cpu, sched_group_span(sg)); cpumask_set_cpu(cpu, group_balance_mask(sg)); } sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg)); sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; return sg; } /* * build_sched_groups will build a circular linked list of the groups * covered by the given span, will set each group's ->cpumask correctly, * and will initialize their ->sgc. * * Assumes the sched_domain tree is fully constructed */ static int build_sched_groups(struct sched_domain *sd, int cpu) { struct sched_group *first = NULL, *last = NULL; struct sd_data *sdd = sd->private; const struct cpumask *span = sched_domain_span(sd); struct cpumask *covered; int i; lockdep_assert_held(&sched_domains_mutex); covered = sched_domains_tmpmask; cpumask_clear(covered); for_each_cpu_wrap(i, span, cpu) { struct sched_group *sg; if (cpumask_test_cpu(i, covered)) continue; sg = get_group(i, sdd); cpumask_or(covered, covered, sched_group_span(sg)); if (!first) first = sg; if (last) last->next = sg; last = sg; } last->next = first; sd->groups = first; return 0; } /* * Initialize sched groups cpu_capacity. * * cpu_capacity indicates the capacity of sched group, which is used while * distributing the load between different sched groups in a sched domain. * Typically cpu_capacity for all the groups in a sched domain will be same * unless there are asymmetries in the topology. If there are asymmetries, * group having more cpu_capacity will pickup more load compared to the * group having less cpu_capacity. */ static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) { struct sched_group *sg = sd->groups; struct cpumask *mask = sched_domains_tmpmask2; WARN_ON(!sg); do { int cpu, cores = 0, max_cpu = -1; sg->group_weight = cpumask_weight(sched_group_span(sg)); cpumask_copy(mask, sched_group_span(sg)); for_each_cpu(cpu, mask) { cores++; #ifdef CONFIG_SCHED_SMT cpumask_andnot(mask, mask, cpu_smt_mask(cpu)); #endif } sg->cores = cores; if (!(sd->flags & SD_ASYM_PACKING)) goto next; for_each_cpu(cpu, sched_group_span(sg)) { if (max_cpu < 0) max_cpu = cpu; else if (sched_asym_prefer(cpu, max_cpu)) max_cpu = cpu; } sg->asym_prefer_cpu = max_cpu; next: sg = sg->next; } while (sg != sd->groups); if (cpu != group_balance_cpu(sg)) return; update_group_capacity(sd, cpu); } /* * Asymmetric CPU capacity bits */ struct asym_cap_data { struct list_head link; unsigned long capacity; unsigned long cpus[]; }; /* * Set of available CPUs grouped by their corresponding capacities * Each list entry contains a CPU mask reflecting CPUs that share the same * capacity. * The lifespan of data is unlimited. */ static LIST_HEAD(asym_cap_list); #define cpu_capacity_span(asym_data) to_cpumask((asym_data)->cpus) /* * Verify whether there is any CPU capacity asymmetry in a given sched domain. * Provides sd_flags reflecting the asymmetry scope. */ static inline int asym_cpu_capacity_classify(const struct cpumask *sd_span, const struct cpumask *cpu_map) { struct asym_cap_data *entry; int count = 0, miss = 0; /* * Count how many unique CPU capacities this domain spans across * (compare sched_domain CPUs mask with ones representing available * CPUs capacities). Take into account CPUs that might be offline: * skip those. */ list_for_each_entry(entry, &asym_cap_list, link) { if (cpumask_intersects(sd_span, cpu_capacity_span(entry))) ++count; else if (cpumask_intersects(cpu_map, cpu_capacity_span(entry))) ++miss; } WARN_ON_ONCE(!count && !list_empty(&asym_cap_list)); /* No asymmetry detected */ if (count < 2) return 0; /* Some of the available CPU capacity values have not been detected */ if (miss) return SD_ASYM_CPUCAPACITY; /* Full asymmetry */ return SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL; } static inline void asym_cpu_capacity_update_data(int cpu) { unsigned long capacity = arch_scale_cpu_capacity(cpu); struct asym_cap_data *entry = NULL; list_for_each_entry(entry, &asym_cap_list, link) { if (capacity == entry->capacity) goto done; } entry = kzalloc(sizeof(*entry) + cpumask_size(), GFP_KERNEL); if (WARN_ONCE(!entry, "Failed to allocate memory for asymmetry data\n")) return; entry->capacity = capacity; list_add(&entry->link, &asym_cap_list); done: __cpumask_set_cpu(cpu, cpu_capacity_span(entry)); } /* * Build-up/update list of CPUs grouped by their capacities * An update requires explicit request to rebuild sched domains * with state indicating CPU topology changes. */ static void asym_cpu_capacity_scan(void) { struct asym_cap_data *entry, *next; int cpu; list_for_each_entry(entry, &asym_cap_list, link) cpumask_clear(cpu_capacity_span(entry)); for_each_cpu_and(cpu, cpu_possible_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)) asym_cpu_capacity_update_data(cpu); list_for_each_entry_safe(entry, next, &asym_cap_list, link) { if (cpumask_empty(cpu_capacity_span(entry))) { list_del(&entry->link); kfree(entry); } } /* * Only one capacity value has been detected i.e. this system is symmetric. * No need to keep this data around. */ if (list_is_singular(&asym_cap_list)) { entry = list_first_entry(&asym_cap_list, typeof(*entry), link); list_del(&entry->link); kfree(entry); } } /* * Initializers for schedule domains * Non-inlined to reduce accumulated stack pressure in build_sched_domains() */ static int default_relax_domain_level = -1; int sched_domain_level_max; static int __init setup_relax_domain_level(char *str) { if (kstrtoint(str, 0, &default_relax_domain_level)) pr_warn("Unable to set relax_domain_level\n"); return 1; } __setup("relax_domain_level=", setup_relax_domain_level); static void set_domain_attribute(struct sched_domain *sd, struct sched_domain_attr *attr) { int request; if (!attr || attr->relax_domain_level < 0) { if (default_relax_domain_level < 0) return; request = default_relax_domain_level; } else request = attr->relax_domain_level; if (sd->level > request) { /* Turn off idle balance on this domain: */ sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); } } static void __sdt_free(const struct cpumask *cpu_map); static int __sdt_alloc(const struct cpumask *cpu_map); static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { switch (what) { case sa_rootdomain: if (!atomic_read(&d->rd->refcount)) free_rootdomain(&d->rd->rcu); fallthrough; case sa_sd: free_percpu(d->sd); fallthrough; case sa_sd_storage: __sdt_free(cpu_map); fallthrough; case sa_none: break; } } static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { memset(d, 0, sizeof(*d)); if (__sdt_alloc(cpu_map)) return sa_sd_storage; d->sd = alloc_percpu(struct sched_domain *); if (!d->sd) return sa_sd_storage; d->rd = alloc_rootdomain(); if (!d->rd) return sa_sd; return sa_rootdomain; } /* * NULL the sd_data elements we've used to build the sched_domain and * sched_group structure so that the subsequent __free_domain_allocs() * will not free the data we're using. */ static void claim_allocations(int cpu, struct sched_domain *sd) { struct sd_data *sdd = sd->private; WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); *per_cpu_ptr(sdd->sd, cpu) = NULL; if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref)) *per_cpu_ptr(sdd->sds, cpu) = NULL; if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) *per_cpu_ptr(sdd->sg, cpu) = NULL; if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) *per_cpu_ptr(sdd->sgc, cpu) = NULL; } #ifdef CONFIG_NUMA enum numa_topology_type sched_numa_topology_type; static int sched_domains_numa_levels; static int sched_domains_curr_level; int sched_max_numa_distance; static int *sched_domains_numa_distance; static struct cpumask ***sched_domains_numa_masks; #endif /* * SD_flags allowed in topology descriptions. * * These flags are purely descriptive of the topology and do not prescribe * behaviour. Behaviour is artificial and mapped in the below sd_init() * function: * * SD_SHARE_CPUCAPACITY - describes SMT topologies * SD_SHARE_PKG_RESOURCES - describes shared caches * SD_NUMA - describes NUMA topologies * * Odd one out, which beside describing the topology has a quirk also * prescribes the desired behaviour that goes along with it: * * SD_ASYM_PACKING - describes SMT quirks */ #define TOPOLOGY_SD_FLAGS \ (SD_SHARE_CPUCAPACITY | \ SD_CLUSTER | \ SD_SHARE_PKG_RESOURCES | \ SD_NUMA | \ SD_ASYM_PACKING) static struct sched_domain * sd_init(struct sched_domain_topology_level *tl, const struct cpumask *cpu_map, struct sched_domain *child, int cpu) { struct sd_data *sdd = &tl->data; struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); int sd_id, sd_weight, sd_flags = 0; struct cpumask *sd_span; #ifdef CONFIG_NUMA /* * Ugly hack to pass state to sd_numa_mask()... */ sched_domains_curr_level = tl->numa_level; #endif sd_weight = cpumask_weight(tl->mask(cpu)); if (tl->sd_flags) sd_flags = (*tl->sd_flags)(); if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, "wrong sd_flags in topology description\n")) sd_flags &= TOPOLOGY_SD_FLAGS; *sd = (struct sched_domain){ .min_interval = sd_weight, .max_interval = 2*sd_weight, .busy_factor = 16, .imbalance_pct = 117, .cache_nice_tries = 0, .flags = 1*SD_BALANCE_NEWIDLE | 1*SD_BALANCE_EXEC | 1*SD_BALANCE_FORK | 0*SD_BALANCE_WAKE | 1*SD_WAKE_AFFINE | 0*SD_SHARE_CPUCAPACITY | 0*SD_SHARE_PKG_RESOURCES | 0*SD_SERIALIZE | 1*SD_PREFER_SIBLING | 0*SD_NUMA | sd_flags , .last_balance = jiffies, .balance_interval = sd_weight, .max_newidle_lb_cost = 0, .last_decay_max_lb_cost = jiffies, .child = child, #ifdef CONFIG_SCHED_DEBUG .name = tl->name, #endif }; sd_span = sched_domain_span(sd); cpumask_and(sd_span, cpu_map, tl->mask(cpu)); sd_id = cpumask_first(sd_span); sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map); WARN_ONCE((sd->flags & (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY)) == (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY), "CPU capacity asymmetry not supported on SMT\n"); /* * Convert topological properties into behaviour. */ /* Don't attempt to spread across CPUs of different capacities. */ if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child) sd->child->flags &= ~SD_PREFER_SIBLING; if (sd->flags & SD_SHARE_CPUCAPACITY) { sd->imbalance_pct = 110; } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { sd->imbalance_pct = 117; sd->cache_nice_tries = 1; #ifdef CONFIG_NUMA } else if (sd->flags & SD_NUMA) { sd->cache_nice_tries = 2; sd->flags &= ~SD_PREFER_SIBLING; sd->flags |= SD_SERIALIZE; if (sched_domains_numa_distance[tl->numa_level] > node_reclaim_distance) { sd->flags &= ~(SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE); } #endif } else { sd->cache_nice_tries = 1; } /* * For all levels sharing cache; connect a sched_domain_shared * instance. */ if (sd->flags & SD_SHARE_PKG_RESOURCES) { sd->shared = *per_cpu_ptr(sdd->sds, sd_id); atomic_inc(&sd->shared->ref); atomic_set(&sd->shared->nr_busy_cpus, sd_weight); } sd->private = sdd; return sd; } /* * Topology list, bottom-up. */ static struct sched_domain_topology_level default_topology[] = { #ifdef CONFIG_SCHED_SMT { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, #endif #ifdef CONFIG_SCHED_CLUSTER { cpu_clustergroup_mask, cpu_cluster_flags, SD_INIT_NAME(CLS) }, #endif #ifdef CONFIG_SCHED_MC { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, #endif { cpu_cpu_mask, SD_INIT_NAME(PKG) }, { NULL, }, }; static struct sched_domain_topology_level *sched_domain_topology = default_topology; static struct sched_domain_topology_level *sched_domain_topology_saved; #define for_each_sd_topology(tl) \ for (tl = sched_domain_topology; tl->mask; tl++) void __init set_sched_topology(struct sched_domain_topology_level *tl) { if (WARN_ON_ONCE(sched_smp_initialized)) return; sched_domain_topology = tl; sched_domain_topology_saved = NULL; } #ifdef CONFIG_NUMA static const struct cpumask *sd_numa_mask(int cpu) { return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; } static void sched_numa_warn(const char *str) { static int done = false; int i,j; if (done) return; done = true; printk(KERN_WARNING "ERROR: %s\n\n", str); for (i = 0; i < nr_node_ids; i++) { printk(KERN_WARNING " "); for (j = 0; j < nr_node_ids; j++) { if (!node_state(i, N_CPU) || !node_state(j, N_CPU)) printk(KERN_CONT "(%02d) ", node_distance(i,j)); else printk(KERN_CONT " %02d ", node_distance(i,j)); } printk(KERN_CONT "\n"); } printk(KERN_WARNING "\n"); } bool find_numa_distance(int distance) { bool found = false; int i, *distances; if (distance == node_distance(0, 0)) return true; rcu_read_lock(); distances = rcu_dereference(sched_domains_numa_distance); if (!distances) goto unlock; for (i = 0; i < sched_domains_numa_levels; i++) { if (distances[i] == distance) { found = true; break; } } unlock: rcu_read_unlock(); return found; } #define for_each_cpu_node_but(n, nbut) \ for_each_node_state(n, N_CPU) \ if (n == nbut) \ continue; \ else /* * A system can have three types of NUMA topology: * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes * NUMA_BACKPLANE: nodes can reach other nodes through a backplane * * The difference between a glueless mesh topology and a backplane * topology lies in whether communication between not directly * connected nodes goes through intermediary nodes (where programs * could run), or through backplane controllers. This affects * placement of programs. * * The type of topology can be discerned with the following tests: * - If the maximum distance between any nodes is 1 hop, the system * is directly connected. * - If for two nodes A and B, located N > 1 hops away from each other, * there is an intermediary node C, which is < N hops away from both * nodes A and B, the system is a glueless mesh. */ static void init_numa_topology_type(int offline_node) { int a, b, c, n; n = sched_max_numa_distance; if (sched_domains_numa_levels <= 2) { sched_numa_topology_type = NUMA_DIRECT; return; } for_each_cpu_node_but(a, offline_node) { for_each_cpu_node_but(b, offline_node) { /* Find two nodes furthest removed from each other. */ if (node_distance(a, b) < n) continue; /* Is there an intermediary node between a and b? */ for_each_cpu_node_but(c, offline_node) { if (node_distance(a, c) < n && node_distance(b, c) < n) { sched_numa_topology_type = NUMA_GLUELESS_MESH; return; } } sched_numa_topology_type = NUMA_BACKPLANE; return; } } pr_err("Failed to find a NUMA topology type, defaulting to DIRECT\n"); sched_numa_topology_type = NUMA_DIRECT; } #define NR_DISTANCE_VALUES (1 << DISTANCE_BITS) void sched_init_numa(int offline_node) { struct sched_domain_topology_level *tl; unsigned long *distance_map; int nr_levels = 0; int i, j; int *distances; struct cpumask ***masks; /* * O(nr_nodes^2) deduplicating selection sort -- in order to find the * unique distances in the node_distance() table. */ distance_map = bitmap_alloc(NR_DISTANCE_VALUES, GFP_KERNEL); if (!distance_map) return; bitmap_zero(distance_map, NR_DISTANCE_VALUES); for_each_cpu_node_but(i, offline_node) { for_each_cpu_node_but(j, offline_node) { int distance = node_distance(i, j); if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) { sched_numa_warn("Invalid distance value range"); bitmap_free(distance_map); return; } bitmap_set(distance_map, distance, 1); } } /* * We can now figure out how many unique distance values there are and * allocate memory accordingly. */ nr_levels = bitmap_weight(distance_map, NR_DISTANCE_VALUES); distances = kcalloc(nr_levels, sizeof(int), GFP_KERNEL); if (!distances) { bitmap_free(distance_map); return; } for (i = 0, j = 0; i < nr_levels; i++, j++) { j = find_next_bit(distance_map, NR_DISTANCE_VALUES, j); distances[i] = j; } rcu_assign_pointer(sched_domains_numa_distance, distances); bitmap_free(distance_map); /* * 'nr_levels' contains the number of unique distances * * The sched_domains_numa_distance[] array includes the actual distance * numbers. */ /* * Here, we should temporarily reset sched_domains_numa_levels to 0. * If it fails to allocate memory for array sched_domains_numa_masks[][], * the array will contain less then 'nr_levels' members. This could be * dangerous when we use it to iterate array sched_domains_numa_masks[][] * in other functions. * * We reset it to 'nr_levels' at the end of this function. */ sched_domains_numa_levels = 0; masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL); if (!masks) return; /* * Now for each level, construct a mask per node which contains all * CPUs of nodes that are that many hops away from us. */ for (i = 0; i < nr_levels; i++) { masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); if (!masks[i]) return; for_each_cpu_node_but(j, offline_node) { struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); int k; if (!mask) return; masks[i][j] = mask; for_each_cpu_node_but(k, offline_node) { if (sched_debug() && (node_distance(j, k) != node_distance(k, j))) sched_numa_warn("Node-distance not symmetric"); if (node_distance(j, k) > sched_domains_numa_distance[i]) continue; cpumask_or(mask, mask, cpumask_of_node(k)); } } } rcu_assign_pointer(sched_domains_numa_masks, masks); /* Compute default topology size */ for (i = 0; sched_domain_topology[i].mask; i++); tl = kzalloc((i + nr_levels + 1) * sizeof(struct sched_domain_topology_level), GFP_KERNEL); if (!tl) return; /* * Copy the default topology bits.. */ for (i = 0; sched_domain_topology[i].mask; i++) tl[i] = sched_domain_topology[i]; /* * Add the NUMA identity distance, aka single NODE. */ tl[i++] = (struct sched_domain_topology_level){ .mask = sd_numa_mask, .numa_level = 0, SD_INIT_NAME(NODE) }; /* * .. and append 'j' levels of NUMA goodness. */ for (j = 1; j < nr_levels; i++, j++) { tl[i] = (struct sched_domain_topology_level){ .mask = sd_numa_mask, .sd_flags = cpu_numa_flags, .flags = SDTL_OVERLAP, .numa_level = j, SD_INIT_NAME(NUMA) }; } sched_domain_topology_saved = sched_domain_topology; sched_domain_topology = tl; sched_domains_numa_levels = nr_levels; WRITE_ONCE(sched_max_numa_distance, sched_domains_numa_distance[nr_levels - 1]); init_numa_topology_type(offline_node); } static void sched_reset_numa(void) { int nr_levels, *distances; struct cpumask ***masks; nr_levels = sched_domains_numa_levels; sched_domains_numa_levels = 0; sched_max_numa_distance = 0; sched_numa_topology_type = NUMA_DIRECT; distances = sched_domains_numa_distance; rcu_assign_pointer(sched_domains_numa_distance, NULL); masks = sched_domains_numa_masks; rcu_assign_pointer(sched_domains_numa_masks, NULL); if (distances || masks) { int i, j; synchronize_rcu(); kfree(distances); for (i = 0; i < nr_levels && masks; i++) { if (!masks[i]) continue; for_each_node(j) kfree(masks[i][j]); kfree(masks[i]); } kfree(masks); } if (sched_domain_topology_saved) { kfree(sched_domain_topology); sched_domain_topology = sched_domain_topology_saved; sched_domain_topology_saved = NULL; } } /* * Call with hotplug lock held */ void sched_update_numa(int cpu, bool online) { int node; node = cpu_to_node(cpu); /* * Scheduler NUMA topology is updated when the first CPU of a * node is onlined or the last CPU of a node is offlined. */ if (cpumask_weight(cpumask_of_node(node)) != 1) return; sched_reset_numa(); sched_init_numa(online ? NUMA_NO_NODE : node); } void sched_domains_numa_masks_set(unsigned int cpu) { int node = cpu_to_node(cpu); int i, j; for (i = 0; i < sched_domains_numa_levels; i++) { for (j = 0; j < nr_node_ids; j++) { if (!node_state(j, N_CPU)) continue; /* Set ourselves in the remote node's masks */ if (node_distance(j, node) <= sched_domains_numa_distance[i]) cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); } } } void sched_domains_numa_masks_clear(unsigned int cpu) { int i, j; for (i = 0; i < sched_domains_numa_levels; i++) { for (j = 0; j < nr_node_ids; j++) { if (sched_domains_numa_masks[i][j]) cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); } } } /* * sched_numa_find_closest() - given the NUMA topology, find the cpu * closest to @cpu from @cpumask. * cpumask: cpumask to find a cpu from * cpu: cpu to be close to * * returns: cpu, or nr_cpu_ids when nothing found. */ int sched_numa_find_closest(const struct cpumask *cpus, int cpu) { int i, j = cpu_to_node(cpu), found = nr_cpu_ids; struct cpumask ***masks; rcu_read_lock(); masks = rcu_dereference(sched_domains_numa_masks); if (!masks) goto unlock; for (i = 0; i < sched_domains_numa_levels; i++) { if (!masks[i][j]) break; cpu = cpumask_any_and(cpus, masks[i][j]); if (cpu < nr_cpu_ids) { found = cpu; break; } } unlock: rcu_read_unlock(); return found; } struct __cmp_key { const struct cpumask *cpus; struct cpumask ***masks; int node; int cpu; int w; }; static int hop_cmp(const void *a, const void *b) { struct cpumask **prev_hop, **cur_hop = *(struct cpumask ***)b; struct __cmp_key *k = (struct __cmp_key *)a; if (cpumask_weight_and(k->cpus, cur_hop[k->node]) <= k->cpu) return 1; if (b == k->masks) { k->w = 0; return 0; } prev_hop = *((struct cpumask ***)b - 1); k->w = cpumask_weight_and(k->cpus, prev_hop[k->node]); if (k->w <= k->cpu) return 0; return -1; } /** * sched_numa_find_nth_cpu() - given the NUMA topology, find the Nth closest CPU * from @cpus to @cpu, taking into account distance * from a given @node. * @cpus: cpumask to find a cpu from * @cpu: CPU to start searching * @node: NUMA node to order CPUs by distance * * Return: cpu, or nr_cpu_ids when nothing found. */ int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node) { struct __cmp_key k = { .cpus = cpus, .cpu = cpu }; struct cpumask ***hop_masks; int hop, ret = nr_cpu_ids; if (node == NUMA_NO_NODE) return cpumask_nth_and(cpu, cpus, cpu_online_mask); rcu_read_lock(); /* CPU-less node entries are uninitialized in sched_domains_numa_masks */ node = numa_nearest_node(node, N_CPU); k.node = node; k.masks = rcu_dereference(sched_domains_numa_masks); if (!k.masks) goto unlock; hop_masks = bsearch(&k, k.masks, sched_domains_numa_levels, sizeof(k.masks[0]), hop_cmp); hop = hop_masks - k.masks; ret = hop ? cpumask_nth_and_andnot(cpu - k.w, cpus, k.masks[hop][node], k.masks[hop-1][node]) : cpumask_nth_and(cpu, cpus, k.masks[0][node]); unlock: rcu_read_unlock(); return ret; } EXPORT_SYMBOL_GPL(sched_numa_find_nth_cpu); /** * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away from * @node * @node: The node to count hops from. * @hops: Include CPUs up to that many hops away. 0 means local node. * * Return: On success, a pointer to a cpumask of CPUs at most @hops away from * @node, an error value otherwise. * * Requires rcu_lock to be held. Returned cpumask is only valid within that * read-side section, copy it if required beyond that. * * Note that not all hops are equal in distance; see sched_init_numa() for how * distances and masks are handled. * Also note that this is a reflection of sched_domains_numa_masks, which may change * during the lifetime of the system (offline nodes are taken out of the masks). */ const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops) { struct cpumask ***masks; if (node >= nr_node_ids || hops >= sched_domains_numa_levels) return ERR_PTR(-EINVAL); masks = rcu_dereference(sched_domains_numa_masks); if (!masks) return ERR_PTR(-EBUSY); return masks[hops][node]; } EXPORT_SYMBOL_GPL(sched_numa_hop_mask); #endif /* CONFIG_NUMA */ static int __sdt_alloc(const struct cpumask *cpu_map) { struct sched_domain_topology_level *tl; int j; for_each_sd_topology(tl) { struct sd_data *sdd = &tl->data; sdd->sd = alloc_percpu(struct sched_domain *); if (!sdd->sd) return -ENOMEM; sdd->sds = alloc_percpu(struct sched_domain_shared *); if (!sdd->sds) return -ENOMEM; sdd->sg = alloc_percpu(struct sched_group *); if (!sdd->sg) return -ENOMEM; sdd->sgc = alloc_percpu(struct sched_group_capacity *); if (!sdd->sgc) return -ENOMEM; for_each_cpu(j, cpu_map) { struct sched_domain *sd; struct sched_domain_shared *sds; struct sched_group *sg; struct sched_group_capacity *sgc; sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sd) return -ENOMEM; *per_cpu_ptr(sdd->sd, j) = sd; sds = kzalloc_node(sizeof(struct sched_domain_shared), GFP_KERNEL, cpu_to_node(j)); if (!sds) return -ENOMEM; *per_cpu_ptr(sdd->sds, j) = sds; sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sg) return -ENOMEM; sg->next = sg; *per_cpu_ptr(sdd->sg, j) = sg; sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sgc) return -ENOMEM; #ifdef CONFIG_SCHED_DEBUG sgc->id = j; #endif *per_cpu_ptr(sdd->sgc, j) = sgc; } } return 0; } static void __sdt_free(const struct cpumask *cpu_map) { struct sched_domain_topology_level *tl; int j; for_each_sd_topology(tl) { struct sd_data *sdd = &tl->data; for_each_cpu(j, cpu_map) { struct sched_domain *sd; if (sdd->sd) { sd = *per_cpu_ptr(sdd->sd, j); if (sd && (sd->flags & SD_OVERLAP)) free_sched_groups(sd->groups, 0); kfree(*per_cpu_ptr(sdd->sd, j)); } if (sdd->sds) kfree(*per_cpu_ptr(sdd->sds, j)); if (sdd->sg) kfree(*per_cpu_ptr(sdd->sg, j)); if (sdd->sgc) kfree(*per_cpu_ptr(sdd->sgc, j)); } free_percpu(sdd->sd); sdd->sd = NULL; free_percpu(sdd->sds); sdd->sds = NULL; free_percpu(sdd->sg); sdd->sg = NULL; free_percpu(sdd->sgc); sdd->sgc = NULL; } } static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, const struct cpumask *cpu_map, struct sched_domain_attr *attr, struct sched_domain *child, int cpu) { struct sched_domain *sd = sd_init(tl, cpu_map, child, cpu); if (child) { sd->level = child->level + 1; sched_domain_level_max = max(sched_domain_level_max, sd->level); child->parent = sd; if (!cpumask_subset(sched_domain_span(child), sched_domain_span(sd))) { pr_err("BUG: arch topology borken\n"); #ifdef CONFIG_SCHED_DEBUG pr_err(" the %s domain not a subset of the %s domain\n", child->name, sd->name); #endif /* Fixup, ensure @sd has at least @child CPUs. */ cpumask_or(sched_domain_span(sd), sched_domain_span(sd), sched_domain_span(child)); } } set_domain_attribute(sd, attr); return sd; } /* * Ensure topology masks are sane, i.e. there are no conflicts (overlaps) for * any two given CPUs at this (non-NUMA) topology level. */ static bool topology_span_sane(struct sched_domain_topology_level *tl, const struct cpumask *cpu_map, int cpu) { int i; /* NUMA levels are allowed to overlap */ if (tl->flags & SDTL_OVERLAP) return true; /* * Non-NUMA levels cannot partially overlap - they must be either * completely equal or completely disjoint. Otherwise we can end up * breaking the sched_group lists - i.e. a later get_group() pass * breaks the linking done for an earlier span. */ for_each_cpu(i, cpu_map) { if (i == cpu) continue; /* * We should 'and' all those masks with 'cpu_map' to exactly * match the topology we're about to build, but that can only * remove CPUs, which only lessens our ability to detect * overlaps */ if (!cpumask_equal(tl->mask(cpu), tl->mask(i)) && cpumask_intersects(tl->mask(cpu), tl->mask(i))) return false; } return true; } /* * Build sched domains for a given set of CPUs and attach the sched domains * to the individual CPUs */ static int build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr) { enum s_alloc alloc_state = sa_none; struct sched_domain *sd; struct s_data d; struct rq *rq = NULL; int i, ret = -ENOMEM; bool has_asym = false; bool has_cluster = false; if (WARN_ON(cpumask_empty(cpu_map))) goto error; alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) goto error; /* Set up domains for CPUs specified by the cpu_map: */ for_each_cpu(i, cpu_map) { struct sched_domain_topology_level *tl; sd = NULL; for_each_sd_topology(tl) { if (WARN_ON(!topology_span_sane(tl, cpu_map, i))) goto error; sd = build_sched_domain(tl, cpu_map, attr, sd, i); has_asym |= sd->flags & SD_ASYM_CPUCAPACITY; if (tl == sched_domain_topology) *per_cpu_ptr(d.sd, i) = sd; if (tl->flags & SDTL_OVERLAP) sd->flags |= SD_OVERLAP; if (cpumask_equal(cpu_map, sched_domain_span(sd))) break; } } /* Build the groups for the domains */ for_each_cpu(i, cpu_map) { for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { sd->span_weight = cpumask_weight(sched_domain_span(sd)); if (sd->flags & SD_OVERLAP) { if (build_overlap_sched_groups(sd, i)) goto error; } else { if (build_sched_groups(sd, i)) goto error; } } } /* * Calculate an allowed NUMA imbalance such that LLCs do not get * imbalanced. */ for_each_cpu(i, cpu_map) { unsigned int imb = 0; unsigned int imb_span = 1; for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { struct sched_domain *child = sd->child; if (!(sd->flags & SD_SHARE_PKG_RESOURCES) && child && (child->flags & SD_SHARE_PKG_RESOURCES)) { struct sched_domain __rcu *top_p; unsigned int nr_llcs; /* * For a single LLC per node, allow an * imbalance up to 12.5% of the node. This is * arbitrary cutoff based two factors -- SMT and * memory channels. For SMT-2, the intent is to * avoid premature sharing of HT resources but * SMT-4 or SMT-8 *may* benefit from a different * cutoff. For memory channels, this is a very * rough estimate of how many channels may be * active and is based on recent CPUs with * many cores. * * For multiple LLCs, allow an imbalance * until multiple tasks would share an LLC * on one node while LLCs on another node * remain idle. This assumes that there are * enough logical CPUs per LLC to avoid SMT * factors and that there is a correlation * between LLCs and memory channels. */ nr_llcs = sd->span_weight / child->span_weight; if (nr_llcs == 1) imb = sd->span_weight >> 3; else imb = nr_llcs; imb = max(1U, imb); sd->imb_numa_nr = imb; /* Set span based on the first NUMA domain. */ top_p = sd->parent; while (top_p && !(top_p->flags & SD_NUMA)) { top_p = top_p->parent; } imb_span = top_p ? top_p->span_weight : sd->span_weight; } else { int factor = max(1U, (sd->span_weight / imb_span)); sd->imb_numa_nr = imb * factor; } } } /* Calculate CPU capacity for physical packages and nodes */ for (i = nr_cpumask_bits-1; i >= 0; i--) { if (!cpumask_test_cpu(i, cpu_map)) continue; for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { claim_allocations(i, sd); init_sched_groups_capacity(i, sd); } } /* Attach the domains */ rcu_read_lock(); for_each_cpu(i, cpu_map) { unsigned long capacity; rq = cpu_rq(i); sd = *per_cpu_ptr(d.sd, i); capacity = arch_scale_cpu_capacity(i); /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */ if (capacity > READ_ONCE(d.rd->max_cpu_capacity)) WRITE_ONCE(d.rd->max_cpu_capacity, capacity); cpu_attach_domain(sd, d.rd, i); if (lowest_flag_domain(i, SD_CLUSTER)) has_cluster = true; } rcu_read_unlock(); if (has_asym) static_branch_inc_cpuslocked(&sched_asym_cpucapacity); if (has_cluster) static_branch_inc_cpuslocked(&sched_cluster_active); if (rq && sched_debug_verbose) { pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); } ret = 0; error: __free_domain_allocs(&d, alloc_state, cpu_map); return ret; } /* Current sched domains: */ static cpumask_var_t *doms_cur; /* Number of sched domains in 'doms_cur': */ static int ndoms_cur; /* Attributes of custom domains in 'doms_cur' */ static struct sched_domain_attr *dattr_cur; /* * Special case: If a kmalloc() of a doms_cur partition (array of * cpumask) fails, then fallback to a single sched domain, * as determined by the single cpumask fallback_doms. */ static cpumask_var_t fallback_doms; /* * arch_update_cpu_topology lets virtualized architectures update the * CPU core maps. It is supposed to return 1 if the topology changed * or 0 if it stayed the same. */ int __weak arch_update_cpu_topology(void) { return 0; } cpumask_var_t *alloc_sched_domains(unsigned int ndoms) { int i; cpumask_var_t *doms; doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL); if (!doms) return NULL; for (i = 0; i < ndoms; i++) { if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { free_sched_domains(doms, i); return NULL; } } return doms; } void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) { unsigned int i; for (i = 0; i < ndoms; i++) free_cpumask_var(doms[i]); kfree(doms); } /* * Set up scheduler domains and groups. For now this just excludes isolated * CPUs, but could be used to exclude other special cases in the future. */ int __init sched_init_domains(const struct cpumask *cpu_map) { int err; zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL); zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL); zalloc_cpumask_var(&fallback_doms, GFP_KERNEL); arch_update_cpu_topology(); asym_cpu_capacity_scan(); ndoms_cur = 1; doms_cur = alloc_sched_domains(ndoms_cur); if (!doms_cur) doms_cur = &fallback_doms; cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_TYPE_DOMAIN)); err = build_sched_domains(doms_cur[0], NULL); return err; } /* * Detach sched domains from a group of CPUs specified in cpu_map * These CPUs will now be attached to the NULL domain */ static void detach_destroy_domains(const struct cpumask *cpu_map) { unsigned int cpu = cpumask_any(cpu_map); int i; if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu))) static_branch_dec_cpuslocked(&sched_asym_cpucapacity); if (static_branch_unlikely(&sched_cluster_active)) static_branch_dec_cpuslocked(&sched_cluster_active); rcu_read_lock(); for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i); rcu_read_unlock(); } /* handle null as "default" */ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, struct sched_domain_attr *new, int idx_new) { struct sched_domain_attr tmp; /* Fast path: */ if (!new && !cur) return 1; tmp = SD_ATTR_INIT; return !memcmp(cur ? (cur + idx_cur) : &tmp, new ? (new + idx_new) : &tmp, sizeof(struct sched_domain_attr)); } /* * Partition sched domains as specified by the 'ndoms_new' * cpumasks in the array doms_new[] of cpumasks. This compares * doms_new[] to the current sched domain partitioning, doms_cur[]. * It destroys each deleted domain and builds each new domain. * * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. * The masks don't intersect (don't overlap.) We should setup one * sched domain for each mask. CPUs not in any of the cpumasks will * not be load balanced. If the same cpumask appears both in the * current 'doms_cur' domains and in the new 'doms_new', we can leave * it as it is. * * The passed in 'doms_new' should be allocated using * alloc_sched_domains. This routine takes ownership of it and will * free_sched_domains it when done with it. If the caller failed the * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, * and partition_sched_domains() will fallback to the single partition * 'fallback_doms', it also forces the domains to be rebuilt. * * If doms_new == NULL it will be replaced with cpu_online_mask. * ndoms_new == 0 is a special case for destroying existing domains, * and it will not create the default domain. * * Call with hotplug lock and sched_domains_mutex held */ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[], struct sched_domain_attr *dattr_new) { bool __maybe_unused has_eas = false; int i, j, n; int new_topology; lockdep_assert_held(&sched_domains_mutex); /* Let the architecture update CPU core mappings: */ new_topology = arch_update_cpu_topology(); /* Trigger rebuilding CPU capacity asymmetry data */ if (new_topology) asym_cpu_capacity_scan(); if (!doms_new) { WARN_ON_ONCE(dattr_new); n = 0; doms_new = alloc_sched_domains(1); if (doms_new) { n = 1; cpumask_and(doms_new[0], cpu_active_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)); } } else { n = ndoms_new; } /* Destroy deleted domains: */ for (i = 0; i < ndoms_cur; i++) { for (j = 0; j < n && !new_topology; j++) { if (cpumask_equal(doms_cur[i], doms_new[j]) && dattrs_equal(dattr_cur, i, dattr_new, j)) { struct root_domain *rd; /* * This domain won't be destroyed and as such * its dl_bw->total_bw needs to be cleared. It * will be recomputed in function * update_tasks_root_domain(). */ rd = cpu_rq(cpumask_any(doms_cur[i]))->rd; dl_clear_root_domain(rd); goto match1; } } /* No match - a current sched domain not in new doms_new[] */ detach_destroy_domains(doms_cur[i]); match1: ; } n = ndoms_cur; if (!doms_new) { n = 0; doms_new = &fallback_doms; cpumask_and(doms_new[0], cpu_active_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)); } /* Build new domains: */ for (i = 0; i < ndoms_new; i++) { for (j = 0; j < n && !new_topology; j++) { if (cpumask_equal(doms_new[i], doms_cur[j]) && dattrs_equal(dattr_new, i, dattr_cur, j)) goto match2; } /* No match - add a new doms_new */ build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); match2: ; } #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) /* Build perf. domains: */ for (i = 0; i < ndoms_new; i++) { for (j = 0; j < n && !sched_energy_update; j++) { if (cpumask_equal(doms_new[i], doms_cur[j]) && cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) { has_eas = true; goto match3; } } /* No match - add perf. domains for a new rd */ has_eas |= build_perf_domains(doms_new[i]); match3: ; } sched_energy_set(has_eas); #endif /* Remember the new sched domains: */ if (doms_cur != &fallback_doms) free_sched_domains(doms_cur, ndoms_cur); kfree(dattr_cur); doms_cur = doms_new; dattr_cur = dattr_new; ndoms_cur = ndoms_new; update_sched_domain_debugfs(); } /* * Call with hotplug lock held */ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], struct sched_domain_attr *dattr_new) { mutex_lock(&sched_domains_mutex); partition_sched_domains_locked(ndoms_new, doms_new, dattr_new); mutex_unlock(&sched_domains_mutex); }
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