cpuidle: Single/Global registration of idle states
This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.
Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.
Reference:
https://lkml.org/lkml/2011/4/25/83
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index a4e0f1b..9d7bc9f 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -426,7 +426,7 @@
if (action == CPU_ONLINE && pr) {
acpi_processor_ppc_has_changed(pr, 0);
- acpi_processor_cst_has_changed(pr);
+ acpi_processor_hotplug(pr);
acpi_processor_reevaluate_tstate(pr, action);
acpi_processor_tstate_has_changed(pr);
}
@@ -503,8 +503,7 @@
acpi_processor_get_throttling_info(pr);
acpi_processor_get_limit_info(pr);
-
- if (cpuidle_get_driver() == &acpi_idle_driver)
+ if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
acpi_processor_power_init(pr, device);
pr->cdev = thermal_cooling_device_register("Processor", device,
@@ -800,17 +799,9 @@
memset(&errata, 0, sizeof(errata));
- if (!cpuidle_register_driver(&acpi_idle_driver)) {
- printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
- acpi_idle_driver.name);
- } else {
- printk(KERN_DEBUG "ACPI: acpi_idle yielding to %s\n",
- cpuidle_get_driver()->name);
- }
-
result = acpi_bus_register_driver(&acpi_processor_driver);
if (result < 0)
- goto out_cpuidle;
+ return result;
acpi_processor_install_hotplug_notify();
@@ -821,11 +812,6 @@
acpi_processor_throttling_init();
return 0;
-
-out_cpuidle:
- cpuidle_unregister_driver(&acpi_idle_driver);
-
- return result;
}
static void __exit acpi_processor_exit(void)