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linux-next/drivers/acpi/processor_driver.c
Rafael J. Wysocki 3000ce3c52 cpufreq: Use per-policy frequency QoS
Replace the CPU device PM QoS used for the management of min and max
frequency constraints in cpufreq (and its users) with per-policy
frequency QoS to avoid problems with cpufreq policies covering
more then one CPU.

Namely, a cpufreq driver is registered with the subsys interface
which calls cpufreq_add_dev() for each CPU, starting from CPU0, so
currently the PM QoS notifiers are added to the first CPU in the
policy (i.e. CPU0 in the majority of cases).

In turn, when the cpufreq driver is unregistered, the subsys interface
doing that calls cpufreq_remove_dev() for each CPU, starting from CPU0,
and the PM QoS notifiers are only removed when cpufreq_remove_dev() is
called for the last CPU in the policy, say CPUx, which as a rule is
not CPU0 if the policy covers more than one CPU.  Then, the PM QoS
notifiers cannot be removed, because CPUx does not have them, and
they are still there in the device PM QoS notifiers list of CPU0,
which prevents new PM QoS notifiers from being registered for CPU0
on the next attempt to register the cpufreq driver.

The same issue occurs when the first CPU in the policy goes offline
before unregistering the driver.

After this change it does not matter which CPU is the policy CPU at
the driver registration time and whether or not it is online all the
time, because the frequency QoS is per policy and not per CPU.

Fixes: 67d874c3b2 ("cpufreq: Register notifiers with the PM QoS framework")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Diagnosed-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/linux-pm/5ad2624194baa2f53acc1f1e627eb7684c577a19.1562210705.git.viresh.kumar@linaro.org/T/#md2d89e95906b8c91c15f582146173dce2e86e99f
Link: https://lore.kernel.org/linux-pm/20191017094612.6tbkwoq4harsjcqv@vireshk-i7/T/#m30d48cc23b9a80467fbaa16e30f90b3828a5a29b
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-10-21 02:05:21 +02:00

368 lines
8.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* processor_driver.c - ACPI Processor Driver
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
* Copyright (C) 2013, Intel Corporation
* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include "internal.h"
#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
#define ACPI_PROCESSOR_NOTIFY_POWER 0x81
#define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_driver");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Processor Driver");
MODULE_LICENSE("GPL");
static int acpi_processor_start(struct device *dev);
static int acpi_processor_stop(struct device *dev);
static const struct acpi_device_id processor_device_ids[] = {
{ACPI_PROCESSOR_OBJECT_HID, 0},
{ACPI_PROCESSOR_DEVICE_HID, 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, processor_device_ids);
static struct device_driver acpi_processor_driver = {
.name = "processor",
.bus = &cpu_subsys,
.acpi_match_table = processor_device_ids,
.probe = acpi_processor_start,
.remove = acpi_processor_stop,
};
static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
{
struct acpi_device *device = data;
struct acpi_processor *pr;
int saved;
if (device->handle != handle)
return;
pr = acpi_driver_data(device);
if (!pr)
return;
switch (event) {
case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
saved = pr->performance_platform_limit;
acpi_processor_ppc_has_changed(pr, 1);
if (saved == pr->performance_platform_limit)
break;
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event,
pr->performance_platform_limit);
break;
case ACPI_PROCESSOR_NOTIFY_POWER:
acpi_processor_power_state_has_changed(pr);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event, 0);
break;
case ACPI_PROCESSOR_NOTIFY_THROTTLING:
acpi_processor_tstate_has_changed(pr);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event, 0);
break;
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Unsupported event [0x%x]\n", event));
break;
}
return;
}
static int __acpi_processor_start(struct acpi_device *device);
static int acpi_soft_cpu_online(unsigned int cpu)
{
struct acpi_processor *pr = per_cpu(processors, cpu);
struct acpi_device *device;
if (!pr || acpi_bus_get_device(pr->handle, &device))
return 0;
/*
* CPU got physically hotplugged and onlined for the first time:
* Initialize missing things.
*/
if (pr->flags.need_hotplug_init) {
int ret;
pr_info("Will online and init hotplugged CPU: %d\n",
pr->id);
pr->flags.need_hotplug_init = 0;
ret = __acpi_processor_start(device);
WARN(ret, "Failed to start CPU: %d\n", pr->id);
} else {
/* Normal CPU soft online event. */
acpi_processor_ppc_has_changed(pr, 0);
acpi_processor_hotplug(pr);
acpi_processor_reevaluate_tstate(pr, false);
acpi_processor_tstate_has_changed(pr);
}
return 0;
}
static int acpi_soft_cpu_dead(unsigned int cpu)
{
struct acpi_processor *pr = per_cpu(processors, cpu);
struct acpi_device *device;
if (!pr || acpi_bus_get_device(pr->handle, &device))
return 0;
acpi_processor_reevaluate_tstate(pr, true);
return 0;
}
#ifdef CONFIG_ACPI_CPU_FREQ_PSS
static int acpi_pss_perf_init(struct acpi_processor *pr,
struct acpi_device *device)
{
int result = 0;
acpi_processor_ppc_has_changed(pr, 0);
acpi_processor_get_throttling_info(pr);
if (pr->flags.throttling)
pr->flags.limit = 1;
pr->cdev = thermal_cooling_device_register("Processor", device,
&processor_cooling_ops);
if (IS_ERR(pr->cdev)) {
result = PTR_ERR(pr->cdev);
return result;
}
dev_dbg(&device->dev, "registered as cooling_device%d\n",
pr->cdev->id);
result = sysfs_create_link(&device->dev.kobj,
&pr->cdev->device.kobj,
"thermal_cooling");
if (result) {
dev_err(&device->dev,
"Failed to create sysfs link 'thermal_cooling'\n");
goto err_thermal_unregister;
}
result = sysfs_create_link(&pr->cdev->device.kobj,
&device->dev.kobj,
"device");
if (result) {
dev_err(&pr->cdev->device,
"Failed to create sysfs link 'device'\n");
goto err_remove_sysfs_thermal;
}
return 0;
err_remove_sysfs_thermal:
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
err_thermal_unregister:
thermal_cooling_device_unregister(pr->cdev);
return result;
}
static void acpi_pss_perf_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
if (pr->cdev) {
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
sysfs_remove_link(&pr->cdev->device.kobj, "device");
thermal_cooling_device_unregister(pr->cdev);
pr->cdev = NULL;
}
}
#else
static inline int acpi_pss_perf_init(struct acpi_processor *pr,
struct acpi_device *device)
{
return 0;
}
static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
struct acpi_device *device) {}
#endif /* CONFIG_ACPI_CPU_FREQ_PSS */
static int __acpi_processor_start(struct acpi_device *device)
{
struct acpi_processor *pr = acpi_driver_data(device);
acpi_status status;
int result = 0;
if (!pr)
return -ENODEV;
if (pr->flags.need_hotplug_init)
return 0;
result = acpi_cppc_processor_probe(pr);
if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
dev_dbg(&device->dev, "CPPC data invalid or not present\n");
if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
acpi_processor_power_init(pr);
result = acpi_pss_perf_init(pr, device);
if (result)
goto err_power_exit;
status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
acpi_processor_notify, device);
if (ACPI_SUCCESS(status))
return 0;
result = -ENODEV;
acpi_pss_perf_exit(pr, device);
err_power_exit:
acpi_processor_power_exit(pr);
return result;
}
static int acpi_processor_start(struct device *dev)
{
struct acpi_device *device = ACPI_COMPANION(dev);
int ret;
if (!device)
return -ENODEV;
/* Protect against concurrent CPU hotplug operations */
cpu_hotplug_disable();
ret = __acpi_processor_start(device);
cpu_hotplug_enable();
return ret;
}
static int acpi_processor_stop(struct device *dev)
{
struct acpi_device *device = ACPI_COMPANION(dev);
struct acpi_processor *pr;
if (!device)
return 0;
acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
acpi_processor_notify);
pr = acpi_driver_data(device);
if (!pr)
return 0;
acpi_processor_power_exit(pr);
acpi_pss_perf_exit(pr, device);
acpi_cppc_processor_exit(pr);
return 0;
}
bool acpi_processor_cpufreq_init;
static int acpi_processor_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
if (event == CPUFREQ_CREATE_POLICY) {
acpi_thermal_cpufreq_init(policy);
acpi_processor_ppc_init(policy);
} else if (event == CPUFREQ_REMOVE_POLICY) {
acpi_processor_ppc_exit(policy);
acpi_thermal_cpufreq_exit(policy);
}
return 0;
}
static struct notifier_block acpi_processor_notifier_block = {
.notifier_call = acpi_processor_notifier,
};
/*
* We keep the driver loaded even when ACPI is not running.
* This is needed for the powernow-k8 driver, that works even without
* ACPI, but needs symbols from this driver
*/
static enum cpuhp_state hp_online;
static int __init acpi_processor_driver_init(void)
{
int result = 0;
if (acpi_disabled)
return 0;
result = driver_register(&acpi_processor_driver);
if (result < 0)
return result;
result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"acpi/cpu-drv:online",
acpi_soft_cpu_online, NULL);
if (result < 0)
goto err;
hp_online = result;
cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
NULL, acpi_soft_cpu_dead);
if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
CPUFREQ_POLICY_NOTIFIER)) {
acpi_processor_cpufreq_init = true;
acpi_processor_ignore_ppc_init();
}
acpi_processor_throttling_init();
return 0;
err:
driver_unregister(&acpi_processor_driver);
return result;
}
static void __exit acpi_processor_driver_exit(void)
{
if (acpi_disabled)
return;
if (acpi_processor_cpufreq_init) {
cpufreq_unregister_notifier(&acpi_processor_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
acpi_processor_cpufreq_init = false;
}
cpuhp_remove_state_nocalls(hp_online);
cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
driver_unregister(&acpi_processor_driver);
}
module_init(acpi_processor_driver_init);
module_exit(acpi_processor_driver_exit);
MODULE_ALIAS("processor");