linux-kernel - [Patch v4 5/6] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping

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Message-Id: <1571776465-29763-6-git-send-email-thara.gopinath@linaro.org>
Date:   Tue, 22 Oct 2019 16:34:24 -0400
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     mingo@...hat.com, peterz@...radead.org, ionela.voinescu@....com,
        vincent.guittot@...aro.org, rui.zhang@...el.com,
        edubezval@...il.com, qperret@...gle.com
Cc:     linux-kernel@...r.kernel.org, amit.kachhap@...il.com,
        javi.merino@...nel.org, daniel.lezcano@...aro.org
Subject: [Patch v4 5/6] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping

Thermal governors can request for a cpu's maximum supported frequency
to be capped in case of an overheat event. This in turn means that the
maximum capacity available for tasks to run on the particular cpu is
reduced. Delta between the original maximum capacity and capped
maximum capacity is known as thermal pressure. Enable cpufreq cooling
device to update the thermal pressure in event of a capped
maximum frequency.

Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
---
 drivers/thermal/cpu_cooling.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 391f397..2e6a979 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -218,6 +218,23 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
 }
 
 /**
+ * update_sched_max_capacity - update scheduler about change in cpu
+ *					max frequency.
+ * @policy - cpufreq policy whose max frequency is capped.
+ */
+static void update_sched_max_capacity(struct cpumask *cpus,
+				      unsigned int cur_max_freq,
+				      unsigned int max_freq)
+{
+	int cpu;
+	unsigned long capacity = (cur_max_freq << SCHED_CAPACITY_SHIFT) /
+				  max_freq;
+
+	for_each_cpu(cpu, cpus)
+		update_thermal_pressure(cpu, capacity);
+}
+
+/**
  * get_load() - get load for a cpu since last updated
  * @cpufreq_cdev:	&struct cpufreq_cooling_device for this cpu
  * @cpu:	cpu number
@@ -320,6 +337,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 				 unsigned long state)
 {
 	struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
+	int ret;
 
 	/* Request state should be less than max_level */
 	if (WARN_ON(state > cpufreq_cdev->max_level))
@@ -331,8 +349,17 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 
 	cpufreq_cdev->cpufreq_state = state;
 
-	return dev_pm_qos_update_request(&cpufreq_cdev->qos_req,
-				cpufreq_cdev->freq_table[state].frequency);
+	ret = dev_pm_qos_update_request
+				(&cpufreq_cdev->qos_req,
+				 cpufreq_cdev->freq_table[state].frequency);
+
+	if (ret > 0)
+		update_sched_max_capacity
+				(cpufreq_cdev->policy->cpus,
+				 cpufreq_cdev->freq_table[state].frequency,
+				 cpufreq_cdev->policy->cpuinfo.max_freq);
+
+	return ret;
 }
 
 /**
-- 
2.1.4