1 files changed, 45 insertions, 46 deletions

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 10d1391e7416..63aecd2a7a9f 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -657,13 +657,13 @@ static void destroy_sched_domains(struct sched_domain *sd)
 }
 
 /*
- * 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().
+ * Keep a special pointer to the highest sched_domain that has SD_SHARE_LLC 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().
+ * 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);
@@ -684,7 +684,7 @@ static void update_top_cache_domain(int cpu)
 	int id = cpu;
 	int size = 1;
 
-	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
+	sd = highest_flag_domain(cpu, SD_SHARE_LLC);
 	if (sd) {
 		id = cpumask_first(sched_domain_span(sd));
 		size = cpumask_weight(sched_domain_span(sd));
@@ -1330,23 +1330,12 @@ next:
 }
 
 /*
- * 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)
+LIST_HEAD(asym_cap_list);
 
 /*
  * Verify whether there is any CPU capacity asymmetry in a given sched domain.
@@ -1386,21 +1375,39 @@ asym_cpu_capacity_classify(const struct cpumask *sd_span,
 
 }
 
+static void free_asym_cap_entry(struct rcu_head *head)
+{
+	struct asym_cap_data *entry = container_of(head, struct asym_cap_data, rcu);
+	kfree(entry);
+}
+
 static inline void asym_cpu_capacity_update_data(int cpu)
 {
 	unsigned long capacity = arch_scale_cpu_capacity(cpu);
-	struct asym_cap_data *entry = NULL;
+	struct asym_cap_data *insert_entry = NULL;
+	struct asym_cap_data *entry;
 
+	/*
+	 * Search if capacity already exits. If not, track which the entry
+	 * where we should insert to keep the list ordered descendingly.
+	 */
 	list_for_each_entry(entry, &asym_cap_list, link) {
 		if (capacity == entry->capacity)
 			goto done;
+		else if (!insert_entry && capacity > entry->capacity)
+			insert_entry = list_prev_entry(entry, link);
 	}
 
 	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);
+
+	/* If NULL then the new capacity is the smallest, add last. */
+	if (!insert_entry)
+		list_add_tail_rcu(&entry->link, &asym_cap_list);
+	else
+		list_add_rcu(&entry->link, &insert_entry->link);
 done:
 	__cpumask_set_cpu(cpu, cpu_capacity_span(entry));
 }
@@ -1423,8 +1430,8 @@ static void asym_cpu_capacity_scan(void)
 
 	list_for_each_entry_safe(entry, next, &asym_cap_list, link) {
 		if (cpumask_empty(cpu_capacity_span(entry))) {
-			list_del(&entry->link);
-			kfree(entry);
+			list_del_rcu(&entry->link);
+			call_rcu(&entry->rcu, free_asym_cap_entry);
 		}
 	}
 
@@ -1434,8 +1441,8 @@ static void asym_cpu_capacity_scan(void)
 	 */
 	if (list_is_singular(&asym_cap_list)) {
 		entry = list_first_entry(&asym_cap_list, typeof(*entry), link);
-		list_del(&entry->link);
-		kfree(entry);
+		list_del_rcu(&entry->link);
+		call_rcu(&entry->rcu, free_asym_cap_entry);
 	}
 }
 
@@ -1551,11 +1558,12 @@ static struct cpumask		***sched_domains_numa_masks;
  *
  * These flags are purely descriptive of the topology and do not prescribe
  * behaviour. Behaviour is artificial and mapped in the below sd_init()
- * function:
+ * function. For details, see include/linux/sched/sd_flags.h.
  *
- *   SD_SHARE_CPUCAPACITY   - describes SMT topologies
- *   SD_SHARE_PKG_RESOURCES - describes shared caches
- *   SD_NUMA                - describes NUMA topologies
+ *   SD_SHARE_CPUCAPACITY
+ *   SD_SHARE_LLC
+ *   SD_CLUSTER
+ *   SD_NUMA
  *
  * Odd one out, which beside describing the topology has a quirk also
  * prescribes the desired behaviour that goes along with it:
@@ -1565,7 +1573,7 @@ static struct cpumask		***sched_domains_numa_masks;
 #define TOPOLOGY_SD_FLAGS		\
 	(SD_SHARE_CPUCAPACITY	|	\
 	 SD_CLUSTER		|	\
-	 SD_SHARE_PKG_RESOURCES |	\
+	 SD_SHARE_LLC		|	\
 	 SD_NUMA		|	\
 	 SD_ASYM_PACKING)
 
@@ -1608,7 +1616,7 @@ sd_init(struct sched_domain_topology_level *tl,
 					| 0*SD_BALANCE_WAKE
 					| 1*SD_WAKE_AFFINE
 					| 0*SD_SHARE_CPUCAPACITY
-					| 0*SD_SHARE_PKG_RESOURCES
+					| 0*SD_SHARE_LLC
 					| 0*SD_SERIALIZE
 					| 1*SD_PREFER_SIBLING
 					| 0*SD_NUMA
@@ -1645,7 +1653,7 @@ sd_init(struct sched_domain_topology_level *tl,
 	if (sd->flags & SD_SHARE_CPUCAPACITY) {
 		sd->imbalance_pct = 110;
 
-	} else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+	} else if (sd->flags & SD_SHARE_LLC) {
 		sd->imbalance_pct = 117;
 		sd->cache_nice_tries = 1;
 
@@ -1670,7 +1678,7 @@ sd_init(struct sched_domain_topology_level *tl,
 	 * For all levels sharing cache; connect a sched_domain_shared
 	 * instance.
 	 */
-	if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+	if (sd->flags & SD_SHARE_LLC) {
 		sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
 		atomic_inc(&sd->shared->ref);
 		atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
@@ -2445,8 +2453,8 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 		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)) {
+			if (!(sd->flags & SD_SHARE_LLC) && child &&
+			    (child->flags & SD_SHARE_LLC)) {
 				struct sched_domain __rcu *top_p;
 				unsigned int nr_llcs;
 
@@ -2506,16 +2514,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 	/* Attach the domains */
 	rcu_read_lock();
 	for_each_cpu(i, cpu_map) {
-		unsigned long capacity;
-
 		rq = cpu_rq(i);
 		sd = *per_cpu_ptr(d.sd, i);
 
-		capacity = arch_scale_cpu_capacity(i);
-		/* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
-		if (capacity > READ_ONCE(d.rd->max_cpu_capacity))
-			WRITE_ONCE(d.rd->max_cpu_capacity, capacity);
-
 		cpu_attach_domain(sd, d.rd, i);
 
 		if (lowest_flag_domain(i, SD_CLUSTER))
@@ -2529,10 +2530,8 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 	if (has_cluster)
 		static_branch_inc_cpuslocked(&sched_cluster_active);
 
-	if (rq && sched_debug_verbose) {
-		pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
-			cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
-	}
+	if (rq && sched_debug_verbose)
+		pr_info("root domain span: %*pbl\n", cpumask_pr_args(cpu_map));
 
 	ret = 0;
 error: