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-rw-r--r--kernel/sched/topology.c2647
1 files changed, 2647 insertions, 0 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
new file mode 100644
index 000000000..8739c2a5a
--- /dev/null
+++ b/kernel/sched/topology.c
@@ -0,0 +1,2647 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler topology setup/handling methods
+ */
+
+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;
+DEFINE_MUTEX(sched_energy_mutex);
+bool sched_energy_update;
+
+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;
+
+ 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. the EM complexity is low enough to keep scheduling overheads low;
+ * 5. schedutil is driving the frequency of all CPUs of the rd;
+ * 6. frequency invariance support is present;
+ *
+ * The complexity of the Energy Model is defined as:
+ *
+ * C = nr_pd * (nr_cpus + nr_ps)
+ *
+ * with parameters defined as:
+ * - nr_pd: the number of performance domains
+ * - nr_cpus: the number of CPUs
+ * - nr_ps: the sum of the number of performance states of all performance
+ * domains (for example, on a system with 2 performance domains,
+ * with 10 performance states each, nr_ps = 2 * 10 = 20).
+ *
+ * It is generally not a good idea to use such a model in the wake-up path on
+ * very complex platforms because of the associated scheduling overheads. The
+ * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs
+ * with per-CPU DVFS and less than 8 performance states each, for example.
+ */
+#define EM_MAX_COMPLEXITY 2048
+
+extern struct cpufreq_governor schedutil_gov;
+static bool build_perf_domains(const struct cpumask *cpu_map)
+{
+ int i, nr_pd = 0, nr_ps = 0, nr_cpus = cpumask_weight(cpu_map);
+ struct perf_domain *pd = NULL, *tmp;
+ int cpu = cpumask_first(cpu_map);
+ struct root_domain *rd = cpu_rq(cpu)->rd;
+ struct cpufreq_policy *policy;
+ struct cpufreq_governor *gov;
+
+ if (!sysctl_sched_energy_aware)
+ goto free;
+
+ /* EAS is enabled for asymmetric CPU capacity topologies. */
+ if (!per_cpu(sd_asym_cpucapacity, cpu)) {
+ if (sched_debug()) {
+ pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n",
+ cpumask_pr_args(cpu_map));
+ }
+ goto free;
+ }
+
+ /* EAS definitely does *not* handle SMT */
+ if (sched_smt_active()) {
+ pr_warn("rd %*pbl: Disabling EAS, SMT is not supported\n",
+ cpumask_pr_args(cpu_map));
+ goto free;
+ }
+
+ if (!arch_scale_freq_invariant()) {
+ if (sched_debug()) {
+ pr_warn("rd %*pbl: Disabling EAS: frequency-invariant load tracking not yet supported",
+ cpumask_pr_args(cpu_map));
+ }
+ goto free;
+ }
+
+ for_each_cpu(i, cpu_map) {
+ /* Skip already covered CPUs. */
+ if (find_pd(pd, i))
+ continue;
+
+ /* Do not attempt EAS if schedutil is not being used. */
+ policy = cpufreq_cpu_get(i);
+ if (!policy)
+ goto free;
+ gov = policy->governor;
+ cpufreq_cpu_put(policy);
+ if (gov != &schedutil_gov) {
+ if (rd->pd)
+ pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n",
+ cpumask_pr_args(cpu_map));
+ goto free;
+ }
+
+ /* Create the new pd and add it to the local list. */
+ tmp = pd_init(i);
+ if (!tmp)
+ goto free;
+ tmp->next = pd;
+ pd = tmp;
+
+ /*
+ * Count performance domains and performance states for the
+ * complexity check.
+ */
+ nr_pd++;
+ nr_ps += em_pd_nr_perf_states(pd->em_pd);
+ }
+
+ /* Bail out if the Energy Model complexity is too high. */
+ if (nr_pd * (nr_ps + nr_cpus) > EM_MAX_COMPLEXITY) {
+ WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n",
+ cpumask_pr_args(cpu_map));
+ goto free;
+ }
+
+ 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;
+ unsigned long flags;
+
+ raw_spin_rq_lock_irqsave(rq, flags);
+
+ 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);
+
+ raw_spin_rq_unlock_irqrestore(rq, flags);
+
+ 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_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(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);
+
+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_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;
+ /*
+ * 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 (DIE)
+ *
+ * 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
+ *
+ * DIE [ ]
+ * MC [ ] [ ]
+ * SMT [ ] [ ] [ ] [ ]
+ *
+ * - or -
+ *
+ * DIE 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;
+
+ WARN_ON(!sg);
+
+ do {
+ int cpu, max_cpu = -1;
+
+ sg->group_weight = cpumask_weight(sched_group_span(sg));
+
+ 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_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(DIE) },
+ { 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 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;
+}
+
+#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;
+
+ 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) {
+ rq = cpu_rq(i);
+ sd = *per_cpu_ptr(d.sd, i);
+
+ /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
+ if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
+ WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
+
+ cpu_attach_domain(sd, d.rd, i);
+ }
+ rcu_read_unlock();
+
+ if (has_asym)
+ static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
+
+ 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 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);
+
+ 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);
+}