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/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 0156540..c904188 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -22,6 +22,7 @@
#define CPUIDLE_DESC_LEN 32
struct cpuidle_device;
+struct cpuidle_driver;
/****************************
@@ -45,6 +46,7 @@
unsigned int target_residency; /* in US */
int (*enter) (struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
int index);
};
@@ -83,12 +85,10 @@
struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
- unsigned int power_specified:1;
unsigned int cpu;
int last_residency;
int state_count;
- struct cpuidle_state states[CPUIDLE_STATE_MAX];
struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
@@ -96,7 +96,6 @@
struct kobject kobj;
struct completion kobj_unregister;
void *governor_data;
- int safe_state_index;
};
DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
@@ -120,6 +119,11 @@
struct cpuidle_driver {
char name[CPUIDLE_NAME_LEN];
struct module *owner;
+
+ unsigned int power_specified:1;
+ struct cpuidle_state states[CPUIDLE_STATE_MAX];
+ int state_count;
+ int safe_state_index;
};
#ifdef CONFIG_CPU_IDLE
@@ -166,10 +170,13 @@
struct list_head governor_list;
unsigned int rating;
- int (*enable) (struct cpuidle_device *dev);
- void (*disable) (struct cpuidle_device *dev);
+ int (*enable) (struct cpuidle_driver *drv,
+ struct cpuidle_device *dev);
+ void (*disable) (struct cpuidle_driver *drv,
+ struct cpuidle_device *dev);
- int (*select) (struct cpuidle_device *dev);
+ int (*select) (struct cpuidle_driver *drv,
+ struct cpuidle_device *dev);
void (*reflect) (struct cpuidle_device *dev, int index);
struct module *owner;