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77 lines
2.7 KiB
77 lines
2.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Scheduler code and data structures related to cpufreq. |
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* |
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* Copyright (C) 2016, Intel Corporation |
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* Author: Rafael J. Wysocki <[email protected]> |
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*/ |
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#include <linux/cpufreq.h> |
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#include "sched.h" |
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DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); |
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/** |
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* cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. |
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* @cpu: The CPU to set the pointer for. |
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* @data: New pointer value. |
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* @func: Callback function to set for the CPU. |
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* |
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* Set and publish the update_util_data pointer for the given CPU. |
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* |
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* The update_util_data pointer of @cpu is set to @data and the callback |
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* function pointer in the target struct update_util_data is set to @func. |
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* That function will be called by cpufreq_update_util() from RCU-sched |
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* read-side critical sections, so it must not sleep. @data will always be |
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* passed to it as the first argument which allows the function to get to the |
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* target update_util_data structure and its container. |
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* |
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* The update_util_data pointer of @cpu must be NULL when this function is |
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* called or it will WARN() and return with no effect. |
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*/ |
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void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, |
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void (*func)(struct update_util_data *data, u64 time, |
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unsigned int flags)) |
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{ |
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if (WARN_ON(!data || !func)) |
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return; |
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if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) |
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return; |
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data->func = func; |
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rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); |
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} |
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EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); |
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/** |
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* cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. |
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* @cpu: The CPU to clear the pointer for. |
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* |
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* Clear the update_util_data pointer for the given CPU. |
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* |
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* Callers must use RCU callbacks to free any memory that might be |
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* accessed via the old update_util_data pointer or invoke synchronize_rcu() |
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* right after this function to avoid use-after-free. |
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*/ |
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void cpufreq_remove_update_util_hook(int cpu) |
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{ |
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rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL); |
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} |
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EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook); |
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/** |
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* cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated. |
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* @policy: cpufreq policy to check. |
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* |
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* Return 'true' if: |
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* - the local and remote CPUs share @policy, |
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* - dvfs_possible_from_any_cpu is set in @policy and the local CPU is not going |
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* offline (in which case it is not expected to run cpufreq updates any more). |
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*/ |
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bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy) |
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{ |
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return cpumask_test_cpu(smp_processor_id(), policy->cpus) || |
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(policy->dvfs_possible_from_any_cpu && |
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rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data))); |
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}
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