[PATCH 3/6] sched/topology: Account asym capacities number

[Frederic Weisbecker]

The timer migration code will need to know the number of capacities
in the system and the maximum number of CPUs a capacity can contain
in order to build the tree accordingly.

Prepare the relevant APIs.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
 include/linux/sched/topology.h |  2 ++
 kernel/sched/topology.c        | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index b5d9d7c2b8ad..88632825136e 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -50,6 +50,8 @@ extern const struct cpumask *tl_mc_mask(struct sched_domain_topology_level *tl,
 extern const struct cpumask *tl_pkg_mask(struct sched_domain_topology_level *tl, int cpu);
 
 extern int arch_asym_cpu_priority(int cpu);
+extern int sched_asym_count(void);
+extern int sched_asym_max_cpus(void);
 
 struct sched_domain_attr {
 	int relax_domain_level;
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 622e2e01974c..3b3bd32aea40 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1746,6 +1746,20 @@ static inline void asym_cpu_capacity_update_data(int cpu)
 	__cpumask_set_cpu(cpu, cpu_capacity_span(entry));
 }
 
+static int asym_capacity_nr;
+
+int sched_asym_count(void)
+{
+	return asym_capacity_nr;
+}
+
+static int asym_capacity_max_cpus;
+
+int sched_asym_max_cpus(void)
+{
+	return asym_capacity_max_cpus;
+}
+
 /*
  * Build-up/update list of CPUs grouped by their capacities
  * An update requires explicit request to rebuild sched domains
@@ -1756,6 +1770,9 @@ static void asym_cpu_capacity_scan(void)
 	struct asym_cap_data *entry, *next;
 	int cpu;
 
+	asym_capacity_nr = 0;
+	asym_capacity_max_cpus = 0;
+
 	list_for_each_entry(entry, &asym_cap_list, link)
 		cpumask_clear(cpu_capacity_span(entry));
 
@@ -1766,6 +1783,13 @@ static void asym_cpu_capacity_scan(void)
 		if (cpumask_empty(cpu_capacity_span(entry))) {
 			list_del_rcu(&entry->link);
 			call_rcu(&entry->rcu, free_asym_cap_entry);
+		} else {
+			int weight;
+
+			asym_capacity_nr++;
+			weight = cpumask_weight(cpu_capacity_span(entry));
+			if (weight > asym_capacity_max_cpus)
+				asym_capacity_max_cpus = weight;
 		}
 	}
 
-- 
2.53.0