2 * Scheduler code and data structures related to cpufreq.
4 * Copyright (C) 2016, Intel Corporation
5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
16 * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
17 * @cpu: The CPU to set the pointer for.
18 * @data: New pointer value.
19 * @func: Callback function to set for the CPU.
21 * Set and publish the update_util_data pointer for the given CPU.
23 * The update_util_data pointer of @cpu is set to @data and the callback
24 * function pointer in the target struct update_util_data is set to @func.
25 * That function will be called by cpufreq_update_util() from RCU-sched
26 * read-side critical sections, so it must not sleep. @data will always be
27 * passed to it as the first argument which allows the function to get to the
28 * target update_util_data structure and its container.
30 * The update_util_data pointer of @cpu must be NULL when this function is
31 * called or it will WARN() and return with no effect.
33 void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
34 void (*func)(struct update_util_data *data, u64 time,
37 if (WARN_ON(!data || !func))
40 if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
44 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
46 EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
49 * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
50 * @cpu: The CPU to clear the pointer for.
52 * Clear the update_util_data pointer for the given CPU.
54 * Callers must use RCU-sched callbacks to free any memory that might be
55 * accessed via the old update_util_data pointer or invoke synchronize_sched()
56 * right after this function to avoid use-after-free.
58 void cpufreq_remove_update_util_hook(int cpu)
60 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
62 EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);