Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1922 insertions, 0 deletions

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
new file mode 100644
index 000000000..02e85cd23
--- /dev/null
+++ b/kernel/sched/topology.c
@@ -0,0 +1,1922 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler topology setup/handling methods
+ */
+#include "sched.h"
+
+DEFINE_MUTEX(sched_domains_mutex);
+
+/* Protected by sched_domains_mutex: */
+cpumask_var_t sched_domains_tmpmask;
+cpumask_var_t sched_domains_tmpmask2;
+
+#ifdef CONFIG_SCHED_DEBUG
+
+static int __init sched_debug_setup(char *str)
+{
+	sched_debug_enabled = true;
+
+	return 0;
+}
+early_param("sched_debug", sched_debug_setup);
+
+static inline bool sched_debug(void)
+{
+	return sched_debug_enabled;
+}
+
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
+				  struct cpumask *groupmask)
+{
+	struct sched_group *group = sd->groups;
+
+	cpumask_clear(groupmask);
+
+	printk(KERN_DEBUG "%*s domain-%d: ", level, "", level);
+
+	if (!(sd->flags & SD_LOAD_BALANCE)) {
+		printk("does not load-balance\n");
+		if (sd->parent)
+			printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain has parent");
+		return -1;
+	}
+
+	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);
+	}
+
+	printk(KERN_DEBUG "%*s groups:", level + 1, "");
+	do {
+		if (!group) {
+			printk("\n");
+			printk(KERN_ERR "ERROR: group is NULL\n");
+			break;
+		}
+
+		if (!cpumask_weight(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_enabled)
+		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_enabled 0
+# define sched_domain_debug(sd, cpu) do { } while (0)
+static inline bool sched_debug(void)
+{
+	return false;
+}
+#endif /* CONFIG_SCHED_DEBUG */
+
+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_LOAD_BALANCE |
+			 SD_BALANCE_NEWIDLE |
+			 SD_BALANCE_FORK |
+			 SD_BALANCE_EXEC |
+			 SD_SHARE_CPUCAPACITY |
+			 SD_ASYM_CPUCAPACITY |
+			 SD_SHARE_PKG_RESOURCES |
+			 SD_SHARE_POWERDOMAIN)) {
+		if (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_LOAD_BALANCE |
+				SD_BALANCE_NEWIDLE |
+				SD_BALANCE_FORK |
+				SD_BALANCE_EXEC |
+				SD_ASYM_CPUCAPACITY |
+				SD_SHARE_CPUCAPACITY |
+				SD_SHARE_PKG_RESOURCES |
+				SD_PREFER_SIBLING |
+				SD_SHARE_POWERDOMAIN);
+		if (nr_node_ids == 1)
+			pflags &= ~SD_SERIALIZE;
+	}
+	if (~cflags & pflags)
+		return 0;
+
+	return 1;
+}
+
+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);
+	kfree(rd);
+}
+
+void rq_attach_root(struct rq *rq, struct root_domain *rd)
+{
+	struct root_domain *old_rd = NULL;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rq->lock, 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_unlock_irqrestore(&rq->lock, flags);
+
+	if (old_rd)
+		call_rcu_sched(&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_sched(&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);
+	init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
+#endif
+
+	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 *, sd_llc);
+DEFINE_PER_CPU(int, sd_llc_size);
+DEFINE_PER_CPU(int, sd_llc_id);
+DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain *, sd_asym);
+
+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, 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)
+			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));
+	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_and(sched_group_span(sg), 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;
+}
+
+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;
+
+		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(sd, 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;
+
+	if (child)
+		cpu = cpumask_first(sched_domain_span(child));
+
+	sg = *per_cpu_ptr(sdd->sg, cpu);
+	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
+
+	/* For claim_allocations: */
+	atomic_inc(&sg->ref);
+	atomic_inc(&sg->sgc->ref);
+
+	if (child) {
+		cpumask_copy(sched_group_span(sg), sched_domain_span(child));
+		cpumask_copy(group_balance_mask(sg), sched_group_span(sg));
+	} 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;
+
+	return sg;
+}
+
+/*
+ * build_sched_groups will build a circular linked list of the groups
+ * covered by the given span, and will set each group's ->cpumask correctly,
+ * and ->cpu_capacity to 0.
+ *
+ * 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);
+}
+
+/*
+ * 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;
+		else
+			request = default_relax_domain_level;
+	} else
+		request = attr->relax_domain_level;
+	if (request < sd->level) {
+		/* Turn off idle balance on this domain: */
+		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
+	} else {
+		/* Turn on 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);
+		/* Fall through */
+	case sa_sd:
+		free_percpu(d->sd);
+		/* Fall through */
+	case sa_sd_storage:
+		__sdt_free(cpu_map);
+		/* Fall through */
+	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
+ *   SD_SHARE_POWERDOMAIN   - describes shared power domain
+ *   SD_ASYM_CPUCAPACITY    - describes mixed capacity 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	|	\
+	 SD_ASYM_CPUCAPACITY	|	\
+	 SD_SHARE_POWERDOMAIN)
+
+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;
+
+#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		= 32,
+		.imbalance_pct		= 125,
+
+		.cache_nice_tries	= 0,
+		.busy_idx		= 0,
+		.idle_idx		= 0,
+		.newidle_idx		= 0,
+		.wake_idx		= 0,
+		.forkexec_idx		= 0,
+
+		.flags			= 1*SD_LOAD_BALANCE
+					| 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
+					| 0*SD_PREFER_SIBLING
+					| 0*SD_NUMA
+					| sd_flags
+					,
+
+		.last_balance		= jiffies,
+		.balance_interval	= sd_weight,
+		.smt_gain		= 0,
+		.max_newidle_lb_cost	= 0,
+		.next_decay_max_lb_cost	= jiffies,
+		.child			= child,
+#ifdef CONFIG_SCHED_DEBUG
+		.name			= tl->name,
+#endif
+	};
+
+	cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
+	sd_id = cpumask_first(sched_domain_span(sd));
+
+	/*
+	 * Convert topological properties into behaviour.
+	 */
+
+	if (sd->flags & SD_ASYM_CPUCAPACITY) {
+		struct sched_domain *t = sd;
+
+		for_each_lower_domain(t)
+			t->flags |= SD_BALANCE_WAKE;
+	}
+
+	if (sd->flags & SD_SHARE_CPUCAPACITY) {
+		sd->flags |= SD_PREFER_SIBLING;
+		sd->imbalance_pct = 110;
+		sd->smt_gain = 1178; /* ~15% */
+
+	} else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->flags |= SD_PREFER_SIBLING;
+		sd->imbalance_pct = 117;
+		sd->cache_nice_tries = 1;
+		sd->busy_idx = 2;
+
+#ifdef CONFIG_NUMA
+	} else if (sd->flags & SD_NUMA) {
+		sd->cache_nice_tries = 2;
+		sd->busy_idx = 3;
+		sd->idle_idx = 2;
+
+		sd->flags |= SD_SERIALIZE;
+		if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
+			sd->flags &= ~(SD_BALANCE_EXEC |
+				       SD_BALANCE_FORK |
+				       SD_WAKE_AFFINE);
+		}
+
+#endif
+	} else {
+		sd->flags |= SD_PREFER_SIBLING;
+		sd->cache_nice_tries = 1;
+		sd->busy_idx = 2;
+		sd->idle_idx = 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_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;
+
+#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;
+}
+
+#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++)
+			printk(KERN_CONT "%02d ", node_distance(i,j));
+		printk(KERN_CONT "\n");
+	}
+	printk(KERN_WARNING "\n");
+}
+
+bool find_numa_distance(int distance)
+{
+	int i;
+
+	if (distance == node_distance(0, 0))
+		return true;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (sched_domains_numa_distance[i] == distance)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * 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(void)
+{
+	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_online_node(a) {
+		for_each_online_node(b) {
+			/* 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_online_node(c) {
+				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;
+		}
+	}
+}
+
+
+#define NR_DISTANCE_VALUES (1 << DISTANCE_BITS)
+
+void sched_init_numa(void)
+{
+	struct sched_domain_topology_level *tl;
+	unsigned long *distance_map;
+	int nr_levels = 0;
+	int i, j;
+
+	/*
+	 * 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 (i = 0; i < nr_node_ids; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			int distance = node_distance(i, j);
+
+			if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) {
+				sched_numa_warn("Invalid distance value range");
+				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);
+
+	sched_domains_numa_distance = kcalloc(nr_levels, sizeof(int), GFP_KERNEL);
+	if (!sched_domains_numa_distance) {
+		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);
+		sched_domains_numa_distance[i] = j;
+	}
+
+	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;
+
+	sched_domains_numa_masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
+	if (!sched_domains_numa_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++) {
+		sched_domains_numa_masks[i] =
+			kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
+		if (!sched_domains_numa_masks[i])
+			return;
+
+		for (j = 0; j < nr_node_ids; j++) {
+			struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
+			int k;
+
+			if (!mask)
+				return;
+
+			sched_domains_numa_masks[i][j] = mask;
+
+			for_each_node(k) {
+				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));
+			}
+		}
+	}
+
+	/* 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 = tl;
+
+	sched_domains_numa_levels = nr_levels;
+	sched_max_numa_distance = sched_domains_numa_distance[nr_levels - 1];
+
+	init_numa_topology_type();
+}
+
+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_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++)
+			cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
+	}
+}
+
+#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;
+}
+
+/*
+ * 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;
+	struct sched_domain *sd;
+	struct s_data d;
+	struct rq *rq = NULL;
+	int i, ret = -ENOMEM;
+
+	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) {
+			sd = build_sched_domain(tl, cpu_map, attr, sd, i);
+			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 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 (rq && sched_debug_enabled) {
+		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;
+
+/* Attribues 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. Callers must hold the hotplug lock.
+ * 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();
+	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_FLAG_DOMAIN));
+	err = build_sched_domains(doms_cur[0], NULL);
+	register_sched_domain_sysctl();
+
+	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)
+{
+	int i;
+
+	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 held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+			     struct sched_domain_attr *dattr_new)
+{
+	int i, j, n;
+	int new_topology;
+
+	mutex_lock(&sched_domains_mutex);
+
+	/* Always unregister in case we don't destroy any domains: */
+	unregister_sched_domain_sysctl();
+
+	/* Let the architecture update CPU core mappings: */
+	new_topology = arch_update_cpu_topology();
+
+	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_FLAG_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))
+				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_FLAG_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:
+		;
+	}
+
+	/* 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;
+
+	register_sched_domain_sysctl();
+
+	mutex_unlock(&sched_domains_mutex);
+}