mirror of
https://github.com/torvalds/linux.git
synced 2024-11-29 23:51:37 +00:00
659b66e98b
Call cpuidle_poll_state_init() only if it is needed to avoid doing useless work. Signed-off-by: Li RongQing <lirongqing@baidu.com> [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
147 lines
3.1 KiB
C
147 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* cpuidle driver for haltpoll governor.
|
|
*
|
|
* Copyright 2019 Red Hat, Inc. and/or its affiliates.
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*
|
|
* Authors: Marcelo Tosatti <mtosatti@redhat.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/cpuidle.h>
|
|
#include <linux/module.h>
|
|
#include <linux/sched/idle.h>
|
|
#include <linux/kvm_para.h>
|
|
#include <linux/cpuidle_haltpoll.h>
|
|
|
|
static bool force __read_mostly;
|
|
module_param(force, bool, 0444);
|
|
MODULE_PARM_DESC(force, "Load unconditionally");
|
|
|
|
static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
|
|
static enum cpuhp_state haltpoll_hp_state;
|
|
|
|
static int default_enter_idle(struct cpuidle_device *dev,
|
|
struct cpuidle_driver *drv, int index)
|
|
{
|
|
if (current_clr_polling_and_test()) {
|
|
local_irq_enable();
|
|
return index;
|
|
}
|
|
default_idle();
|
|
return index;
|
|
}
|
|
|
|
static struct cpuidle_driver haltpoll_driver = {
|
|
.name = "haltpoll",
|
|
.governor = "haltpoll",
|
|
.states = {
|
|
{ /* entry 0 is for polling */ },
|
|
{
|
|
.enter = default_enter_idle,
|
|
.exit_latency = 1,
|
|
.target_residency = 1,
|
|
.power_usage = -1,
|
|
.name = "haltpoll idle",
|
|
.desc = "default architecture idle",
|
|
},
|
|
},
|
|
.safe_state_index = 0,
|
|
.state_count = 2,
|
|
};
|
|
|
|
static int haltpoll_cpu_online(unsigned int cpu)
|
|
{
|
|
struct cpuidle_device *dev;
|
|
|
|
dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
|
|
if (!dev->registered) {
|
|
dev->cpu = cpu;
|
|
if (cpuidle_register_device(dev)) {
|
|
pr_notice("cpuidle_register_device %d failed!\n", cpu);
|
|
return -EIO;
|
|
}
|
|
arch_haltpoll_enable(cpu);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int haltpoll_cpu_offline(unsigned int cpu)
|
|
{
|
|
struct cpuidle_device *dev;
|
|
|
|
dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
|
|
if (dev->registered) {
|
|
arch_haltpoll_disable(cpu);
|
|
cpuidle_unregister_device(dev);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void haltpoll_uninit(void)
|
|
{
|
|
if (haltpoll_hp_state)
|
|
cpuhp_remove_state(haltpoll_hp_state);
|
|
cpuidle_unregister_driver(&haltpoll_driver);
|
|
|
|
free_percpu(haltpoll_cpuidle_devices);
|
|
haltpoll_cpuidle_devices = NULL;
|
|
}
|
|
|
|
static bool haltpoll_want(void)
|
|
{
|
|
return kvm_para_has_hint(KVM_HINTS_REALTIME) || force;
|
|
}
|
|
|
|
static int __init haltpoll_init(void)
|
|
{
|
|
int ret;
|
|
struct cpuidle_driver *drv = &haltpoll_driver;
|
|
|
|
/* Do not load haltpoll if idle= is passed */
|
|
if (boot_option_idle_override != IDLE_NO_OVERRIDE)
|
|
return -ENODEV;
|
|
|
|
if (!kvm_para_available() || !haltpoll_want())
|
|
return -ENODEV;
|
|
|
|
cpuidle_poll_state_init(drv);
|
|
|
|
ret = cpuidle_register_driver(drv);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
|
|
if (haltpoll_cpuidle_devices == NULL) {
|
|
cpuidle_unregister_driver(drv);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
|
|
haltpoll_cpu_online, haltpoll_cpu_offline);
|
|
if (ret < 0) {
|
|
haltpoll_uninit();
|
|
} else {
|
|
haltpoll_hp_state = ret;
|
|
ret = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __exit haltpoll_exit(void)
|
|
{
|
|
haltpoll_uninit();
|
|
}
|
|
|
|
module_init(haltpoll_init);
|
|
module_exit(haltpoll_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
|