Files
linux-net/drivers/cpuidle/governor.c
Ulf Hansson 2b8d594742 cpuidle: Respect the CPU system wakeup QoS limit for cpuidle
The CPU system wakeup QoS limit must be respected for the regular cpuidle
state selection. Therefore, let's extend the common governor helper
cpuidle_governor_latency_req(), to take the constraint into account.

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Kevin Hilman (TI) <khilman@baylibre.com>
Tested-by: Kevin Hilman (TI) <khilman@baylibre.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20251125112650.329269-6-ulf.hansson@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-11-25 19:01:29 +01:00

124 lines
2.8 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/cpu.h>
#include <linux/cpuidle.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/pm_qos.h>
#include "cpuidle.h"
char param_governor[CPUIDLE_NAME_LEN];
LIST_HEAD(cpuidle_governors);
struct cpuidle_governor *cpuidle_curr_governor;
struct cpuidle_governor *cpuidle_prev_governor;
/**
* cpuidle_find_governor - finds a governor of the specified name
* @str: the name
*
* Must be called with cpuidle_lock acquired.
*/
struct cpuidle_governor *cpuidle_find_governor(const char *str)
{
struct cpuidle_governor *gov;
list_for_each_entry(gov, &cpuidle_governors, governor_list)
if (!strncasecmp(str, gov->name, CPUIDLE_NAME_LEN))
return gov;
return NULL;
}
/**
* cpuidle_switch_governor - changes the governor
* @gov: the new target governor
* Must be called with cpuidle_lock acquired.
*/
int cpuidle_switch_governor(struct cpuidle_governor *gov)
{
struct cpuidle_device *dev;
if (!gov)
return -EINVAL;
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);
}
cpuidle_curr_governor = gov;
list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
cpuidle_enable_device(dev);
cpuidle_install_idle_handler();
pr_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 ||
!strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) ||
(cpuidle_curr_governor->rating < gov->rating &&
strncasecmp(param_governor, cpuidle_curr_governor->name,
CPUIDLE_NAME_LEN)))
cpuidle_switch_governor(gov);
}
mutex_unlock(&cpuidle_lock);
return ret;
}
/**
* cpuidle_governor_latency_req - Compute a latency constraint for CPU
* @cpu: Target CPU
*/
s64 cpuidle_governor_latency_req(unsigned int cpu)
{
struct device *device = get_cpu_device(cpu);
int device_req = dev_pm_qos_raw_resume_latency(device);
int global_req = cpu_latency_qos_limit();
int global_wake_req = cpu_wakeup_latency_qos_limit();
if (global_req > global_wake_req)
global_req = global_wake_req;
if (device_req > global_req)
device_req = global_req;
return (s64)device_req * NSEC_PER_USEC;
}