arch_topology: Relocate cpu_scale to topology.[h|c]

arch_topology.c provides functionality to parse and scale CPU capacity.
It also provides a corresponding sysfs interface. Some architectures
parse and scale CPU capacity differently as per their own needs. On
Intel processors, for instance, it is responsibility of the Intel
P-state driver.

Relocate the implementation of that interface to a common location in
topology.c. Architectures can use the interface and populate it using
their own mechanisms.

An alternative approach would be to compile arch_topology.c even if
not needed only to get this interface. This approach would create
duplicated and conflicting functionality and data structures.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Tested-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20250419025504.9760-2-ricardo.neri-calderon@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index af0029d30dbec76184629d75a95b4730d5b21122..1037169abb4598f830d59aa17fa522133f8a5700 100644 (file)
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -154,14 +154,6 @@ void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
                per_cpu(arch_freq_scale, i) = scale;
 }
 
-DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
-EXPORT_PER_CPU_SYMBOL_GPL(cpu_scale);
-
-void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
-{
-       per_cpu(cpu_scale, cpu) = capacity;
-}
-
 DEFINE_PER_CPU(unsigned long, hw_pressure);
 
 /**
@@ -207,53 +199,9 @@ void topology_update_hw_pressure(const struct cpumask *cpus,
 }
 EXPORT_SYMBOL_GPL(topology_update_hw_pressure);
 
-static ssize_t cpu_capacity_show(struct device *dev,
-                                struct device_attribute *attr,
-                                char *buf)
-{
-       struct cpu *cpu = container_of(dev, struct cpu, dev);
-
-       return sysfs_emit(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
-}
-
 static void update_topology_flags_workfn(struct work_struct *work);
 static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);
 
-static DEVICE_ATTR_RO(cpu_capacity);
-
-static int cpu_capacity_sysctl_add(unsigned int cpu)
-{
-       struct device *cpu_dev = get_cpu_device(cpu);
-
-       if (!cpu_dev)
-               return -ENOENT;
-
-       device_create_file(cpu_dev, &dev_attr_cpu_capacity);
-
-       return 0;
-}
-
-static int cpu_capacity_sysctl_remove(unsigned int cpu)
-{
-       struct device *cpu_dev = get_cpu_device(cpu);
-
-       if (!cpu_dev)
-               return -ENOENT;
-
-       device_remove_file(cpu_dev, &dev_attr_cpu_capacity);
-
-       return 0;
-}
-
-static int register_cpu_capacity_sysctl(void)
-{
-       cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "topology/cpu-capacity",
-                         cpu_capacity_sysctl_add, cpu_capacity_sysctl_remove);
-
-       return 0;
-}
-subsys_initcall(register_cpu_capacity_sysctl);
-
 static int update_topology;
 
 int topology_update_cpu_topology(void)

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index b962da263eeefcdf6efd47b2c690d5500ec22757..8b42df05feffada71febacf6693efc043fb356c0 100644 (file)
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -208,3 +208,55 @@ static int __init topology_sysfs_init(void)
 }
 
 device_initcall(topology_sysfs_init);
+
+DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
+EXPORT_PER_CPU_SYMBOL_GPL(cpu_scale);
+
+void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
+{
+       per_cpu(cpu_scale, cpu) = capacity;
+}
+
+static ssize_t cpu_capacity_show(struct device *dev,
+                                struct device_attribute *attr,
+                                char *buf)
+{
+       struct cpu *cpu = container_of(dev, struct cpu, dev);
+
+       return sysfs_emit(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
+}
+
+static DEVICE_ATTR_RO(cpu_capacity);
+
+static int cpu_capacity_sysctl_add(unsigned int cpu)
+{
+       struct device *cpu_dev = get_cpu_device(cpu);
+
+       if (!cpu_dev)
+               return -ENOENT;
+
+       device_create_file(cpu_dev, &dev_attr_cpu_capacity);
+
+       return 0;
+}
+
+static int cpu_capacity_sysctl_remove(unsigned int cpu)
+{
+       struct device *cpu_dev = get_cpu_device(cpu);
+
+       if (!cpu_dev)
+               return -ENOENT;
+
+       device_remove_file(cpu_dev, &dev_attr_cpu_capacity);
+
+       return 0;
+}
+
+static int register_cpu_capacity_sysctl(void)
+{
+       cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "topology/cpu-capacity",
+                         cpu_capacity_sysctl_add, cpu_capacity_sysctl_remove);
+
+       return 0;
+}
+subsys_initcall(register_cpu_capacity_sysctl);

diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index 2222e8b03ff4b2708312b1609a88675016e38268..d72d6e5aa2002260f04d76071fa14f35120bb4d8 100644 (file)
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -14,14 +14,6 @@ int topology_update_cpu_topology(void);
 struct device_node;
 bool topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu);
 
-DECLARE_PER_CPU(unsigned long, cpu_scale);
-
-static inline unsigned long topology_get_cpu_scale(int cpu)
-{
-       return per_cpu(cpu_scale, cpu);
-}
-
-void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity);
 
 DECLARE_PER_CPU(unsigned long, capacity_freq_ref);
 

diff --git a/include/linux/topology.h b/include/linux/topology.h
index 24e715f0f6d23a98cc173ed80607b6ce129fa038..cd6b4bdc9cfd37585d8b50026c60eca827743727 100644 (file)
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -332,4 +332,13 @@ sched_numa_hop_mask(unsigned int node, unsigned int hops)
             !IS_ERR_OR_NULL(mask);                                            \
             __hops++)
 
+DECLARE_PER_CPU(unsigned long, cpu_scale);
+
+static inline unsigned long topology_get_cpu_scale(int cpu)
+{
+       return per_cpu(cpu_scale, cpu);
+}
+
+void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity);
+
 #endif /* _LINUX_TOPOLOGY_H */