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7a474350d8
commit fef05776eb upstream.
The tz->lock must be hold during the looping over the instances in that
thermal zone. This lock was missing in the governor code since the
beginning, so it's hard to point into a particular commit.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210422153624.6074-2-lukasz.luba@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* fair_share.c - A simple weight based Thermal governor
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*
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* Copyright (C) 2012 Intel Corp
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* Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#include <linux/thermal.h>
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#include <trace/events/thermal.h>
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#include "thermal_core.h"
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/**
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* get_trip_level: - obtains the current trip level for a zone
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* @tz: thermal zone device
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*/
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static int get_trip_level(struct thermal_zone_device *tz)
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{
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int count = 0;
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int trip_temp;
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enum thermal_trip_type trip_type;
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if (tz->trips == 0 || !tz->ops->get_trip_temp)
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return 0;
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for (count = 0; count < tz->trips; count++) {
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tz->ops->get_trip_temp(tz, count, &trip_temp);
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if (tz->temperature < trip_temp)
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break;
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}
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/*
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* count > 0 only if temperature is greater than first trip
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* point, in which case, trip_point = count - 1
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*/
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if (count > 0) {
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tz->ops->get_trip_type(tz, count - 1, &trip_type);
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trace_thermal_zone_trip(tz, count - 1, trip_type);
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}
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return count;
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}
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static long get_target_state(struct thermal_zone_device *tz,
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struct thermal_cooling_device *cdev, int percentage, int level)
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{
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unsigned long max_state;
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cdev->ops->get_max_state(cdev, &max_state);
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return (long)(percentage * level * max_state) / (100 * tz->trips);
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}
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/**
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* fair_share_throttle - throttles devices associated with the given zone
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* @tz - thermal_zone_device
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* @trip - trip point index
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*
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* Throttling Logic: This uses three parameters to calculate the new
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* throttle state of the cooling devices associated with the given zone.
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*
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* Parameters used for Throttling:
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* P1. max_state: Maximum throttle state exposed by the cooling device.
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* P2. percentage[i]/100:
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* How 'effective' the 'i'th device is, in cooling the given zone.
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* P3. cur_trip_level/max_no_of_trips:
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* This describes the extent to which the devices should be throttled.
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* We do not want to throttle too much when we trip a lower temperature,
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* whereas the throttling is at full swing if we trip critical levels.
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* (Heavily assumes the trip points are in ascending order)
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* new_state of cooling device = P3 * P2 * P1
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*/
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static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
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{
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struct thermal_instance *instance;
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int total_weight = 0;
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int total_instance = 0;
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int cur_trip_level = get_trip_level(tz);
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mutex_lock(&tz->lock);
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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if (instance->trip != trip)
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continue;
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total_weight += instance->weight;
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total_instance++;
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}
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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int percentage;
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struct thermal_cooling_device *cdev = instance->cdev;
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if (instance->trip != trip)
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continue;
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if (!total_weight)
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percentage = 100 / total_instance;
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else
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percentage = (instance->weight * 100) / total_weight;
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instance->target = get_target_state(tz, cdev, percentage,
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cur_trip_level);
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mutex_lock(&instance->cdev->lock);
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instance->cdev->updated = false;
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mutex_unlock(&instance->cdev->lock);
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thermal_cdev_update(cdev);
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}
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mutex_unlock(&tz->lock);
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return 0;
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}
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static struct thermal_governor thermal_gov_fair_share = {
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.name = "fair_share",
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.throttle = fair_share_throttle,
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};
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THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share);
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