58919e83c8
It is useful to know the reason why cpufreq_update_util() has just been called and that can be passed as flags to cpufreq_update_util() and to the ->func() callback in struct update_util_data. However, doing that in addition to passing the util and max arguments they already take would be clumsy, so avoid it. Instead, use the observation that the schedutil governor is part of the scheduler proper, so it can access scheduler data directly. This allows the util and max arguments of cpufreq_update_util() and the ->func() callback in struct update_util_data to be replaced with a flags one, but schedutil has to be modified to follow. Thus make the schedutil governor obtain the CFS utilization information from the scheduler and use the "RT" and "DL" flags instead of the special utilization value of ULONG_MAX to track updates from the RT and DL sched classes. Make it non-modular too to avoid having to export scheduler variables to modules at large. Next, update all of the other users of cpufreq_update_util() and the ->func() callback in struct update_util_data accordingly. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
/*
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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 <rafael.j.wysocki@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include "sched.h"
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DEFINE_PER_CPU(struct update_util_data *, 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-sched callbacks to free any memory that might be
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* accessed via the old update_util_data pointer or invoke synchronize_sched()
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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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