[tip: sched/core] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping

[tip-bot2 for Thara Gopinath]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     f12e4f66ab6a31f17da386b682e5fec87ae46537
Gitweb:        https://git.kernel.org/tip/f12e4f66ab6a31f17da386b682e5fec87ae46537
Author:        Thara Gopinath <thara.gopinath@xxxxxxxxxx>
AuthorDate:    Fri, 21 Feb 2020 19:52:12 -05:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 06 Mar 2020 12:57:21 +01:00

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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200222005213.3873-9-thara.gopinath@xxxxxxxxxx
---
 drivers/thermal/cpufreq_cooling.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index fe83d7a..4ae8c85 100644
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -431,6 +431,10 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 				 unsigned long state)
 {
 	struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
+	struct cpumask *cpus;
+	unsigned int frequency;
+	unsigned long max_capacity, capacity;
+	int ret;
 
 	/* Request state should be less than max_level */
 	if (WARN_ON(state > cpufreq_cdev->max_level))
@@ -442,8 +446,19 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 
 	cpufreq_cdev->cpufreq_state = state;
 
-	return freq_qos_update_request(&cpufreq_cdev->qos_req,
-				get_state_freq(cpufreq_cdev, state));
+	frequency = get_state_freq(cpufreq_cdev, state);
+
+	ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
+
+	if (ret > 0) {
+		cpus = cpufreq_cdev->policy->cpus;
+		max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));
+		capacity = frequency * max_capacity;
+		capacity /= cpufreq_cdev->policy->cpuinfo.max_freq;
+		arch_set_thermal_pressure(cpus, max_capacity - capacity);
+	}
+
+	return ret;
 }
 
 /* Bind cpufreq callbacks to thermal cooling device ops */