62027aea23
useful for disabling cpuidle to fall back to architecture-default idle loop cpuidle drivers and governors will fail to register. on x86 they'll say so: intel_idle: intel_idle yielding to (null) ACPI: acpi_idle yielding to (null) Signed-off-by: Len Brown <len.brown@intel.com>
142 lines
3.2 KiB
C
142 lines
3.2 KiB
C
/*
|
|
* governor.c - governor support
|
|
*
|
|
* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
|
|
* Shaohua Li <shaohua.li@intel.com>
|
|
* Adam Belay <abelay@novell.com>
|
|
*
|
|
* This code is licenced under the GPL.
|
|
*/
|
|
|
|
#include <linux/mutex.h>
|
|
#include <linux/module.h>
|
|
#include <linux/cpuidle.h>
|
|
|
|
#include "cpuidle.h"
|
|
|
|
LIST_HEAD(cpuidle_governors);
|
|
struct cpuidle_governor *cpuidle_curr_governor;
|
|
|
|
/**
|
|
* __cpuidle_find_governor - finds a governor of the specified name
|
|
* @str: the name
|
|
*
|
|
* Must be called with cpuidle_lock acquired.
|
|
*/
|
|
static struct cpuidle_governor * __cpuidle_find_governor(const char *str)
|
|
{
|
|
struct cpuidle_governor *gov;
|
|
|
|
list_for_each_entry(gov, &cpuidle_governors, governor_list)
|
|
if (!strnicmp(str, gov->name, CPUIDLE_NAME_LEN))
|
|
return gov;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* cpuidle_switch_governor - changes the governor
|
|
* @gov: the new target governor
|
|
*
|
|
* NOTE: "gov" can be NULL to specify disabled
|
|
* Must be called with cpuidle_lock acquired.
|
|
*/
|
|
int cpuidle_switch_governor(struct cpuidle_governor *gov)
|
|
{
|
|
struct cpuidle_device *dev;
|
|
|
|
if (gov == cpuidle_curr_governor)
|
|
return 0;
|
|
|
|
cpuidle_uninstall_idle_handler();
|
|
|
|
if (cpuidle_curr_governor) {
|
|
list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
|
|
cpuidle_disable_device(dev);
|
|
module_put(cpuidle_curr_governor->owner);
|
|
}
|
|
|
|
cpuidle_curr_governor = gov;
|
|
|
|
if (gov) {
|
|
if (!try_module_get(cpuidle_curr_governor->owner))
|
|
return -EINVAL;
|
|
list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
|
|
cpuidle_enable_device(dev);
|
|
cpuidle_install_idle_handler();
|
|
printk(KERN_INFO "cpuidle: using governor %s\n", gov->name);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cpuidle_register_governor - registers a governor
|
|
* @gov: the governor
|
|
*/
|
|
int cpuidle_register_governor(struct cpuidle_governor *gov)
|
|
{
|
|
int ret = -EEXIST;
|
|
|
|
if (!gov || !gov->select)
|
|
return -EINVAL;
|
|
|
|
if (cpuidle_disabled())
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&cpuidle_lock);
|
|
if (__cpuidle_find_governor(gov->name) == NULL) {
|
|
ret = 0;
|
|
list_add_tail(&gov->governor_list, &cpuidle_governors);
|
|
if (!cpuidle_curr_governor ||
|
|
cpuidle_curr_governor->rating < gov->rating)
|
|
cpuidle_switch_governor(gov);
|
|
}
|
|
mutex_unlock(&cpuidle_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cpuidle_replace_governor - find a replacement governor
|
|
* @exclude_rating: the rating that will be skipped while looking for
|
|
* new governor.
|
|
*/
|
|
static struct cpuidle_governor *cpuidle_replace_governor(int exclude_rating)
|
|
{
|
|
struct cpuidle_governor *gov;
|
|
struct cpuidle_governor *ret_gov = NULL;
|
|
unsigned int max_rating = 0;
|
|
|
|
list_for_each_entry(gov, &cpuidle_governors, governor_list) {
|
|
if (gov->rating == exclude_rating)
|
|
continue;
|
|
if (gov->rating > max_rating) {
|
|
max_rating = gov->rating;
|
|
ret_gov = gov;
|
|
}
|
|
}
|
|
|
|
return ret_gov;
|
|
}
|
|
|
|
/**
|
|
* cpuidle_unregister_governor - unregisters a governor
|
|
* @gov: the governor
|
|
*/
|
|
void cpuidle_unregister_governor(struct cpuidle_governor *gov)
|
|
{
|
|
if (!gov)
|
|
return;
|
|
|
|
mutex_lock(&cpuidle_lock);
|
|
if (gov == cpuidle_curr_governor) {
|
|
struct cpuidle_governor *new_gov;
|
|
new_gov = cpuidle_replace_governor(gov->rating);
|
|
cpuidle_switch_governor(new_gov);
|
|
}
|
|
list_del(&gov->governor_list);
|
|
mutex_unlock(&cpuidle_lock);
|
|
}
|
|
|