64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
/*
|
|
* Scheduler code and data structures related to cpufreq.
|
|
*
|
|
* Copyright (C) 2016, Intel Corporation
|
|
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include "sched.h"
|
|
|
|
DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
|
|
|
|
/**
|
|
* cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
|
|
* @cpu: The CPU to set the pointer for.
|
|
* @data: New pointer value.
|
|
* @func: Callback function to set for the CPU.
|
|
*
|
|
* Set and publish the update_util_data pointer for the given CPU.
|
|
*
|
|
* The update_util_data pointer of @cpu is set to @data and the callback
|
|
* function pointer in the target struct update_util_data is set to @func.
|
|
* That function will be called by cpufreq_update_util() from RCU-sched
|
|
* read-side critical sections, so it must not sleep. @data will always be
|
|
* passed to it as the first argument which allows the function to get to the
|
|
* target update_util_data structure and its container.
|
|
*
|
|
* The update_util_data pointer of @cpu must be NULL when this function is
|
|
* called or it will WARN() and return with no effect.
|
|
*/
|
|
void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
|
|
void (*func)(struct update_util_data *data, u64 time,
|
|
unsigned long util, unsigned long max))
|
|
{
|
|
if (WARN_ON(!data || !func))
|
|
return;
|
|
|
|
if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
|
|
return;
|
|
|
|
data->func = func;
|
|
rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
|
|
|
|
/**
|
|
* cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
|
|
* @cpu: The CPU to clear the pointer for.
|
|
*
|
|
* Clear the update_util_data pointer for the given CPU.
|
|
*
|
|
* Callers must use RCU-sched callbacks to free any memory that might be
|
|
* accessed via the old update_util_data pointer or invoke synchronize_sched()
|
|
* right after this function to avoid use-after-free.
|
|
*/
|
|
void cpufreq_remove_update_util_hook(int cpu)
|
|
{
|
|
rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
|