linux/kernel/sched/cpufreq.c
Peter Zijlstra 3d7e10188a sched: Make clangd usable
Due to the weird Makefile setup of sched the various files do not
compile as stand alone units. The new generation of editors are trying
to do just this -- mostly to offer fancy things like completions but
also better syntax highlighting and code navigation.

Specifically, I've been playing around with neovim and clangd.

Setting up clangd on the kernel source is a giant pain in the arse
(this really should be improved), but once you do manage, you run into
dumb stuff like the above.

Fix up the scheduler files to at least pretend to work.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/20250523164348.GN39944@noisy.programming.kicks-ass.net
2025-06-11 11:20:53 +02:00

75 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Scheduler code and data structures related to cpufreq.
*
* Copyright (C) 2016, Intel Corporation
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*/
#include "sched.h"
DEFINE_PER_CPU(struct update_util_data __rcu *, 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 int flags))
{
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 callbacks to free any memory that might be
* accessed via the old update_util_data pointer or invoke synchronize_rcu()
* 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);
/**
* cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated.
* @policy: cpufreq policy to check.
*
* Return 'true' if:
* - the local and remote CPUs share @policy,
* - dvfs_possible_from_any_cpu is set in @policy and the local CPU is not going
* offline (in which case it is not expected to run cpufreq updates any more).
*/
bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy)
{
return cpumask_test_cpu(smp_processor_id(), policy->cpus) ||
(policy->dvfs_possible_from_any_cpu &&
rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)));
}