linux-kernel - [PATCH v1 08/16] thermal: gov_step_wise: Use .manage() callback instead of .throttle()

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Date: Wed, 10 Apr 2024 18:13:55 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Lukasz Luba <lukasz.luba@....com>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject:
 [PATCH v1 08/16] thermal: gov_step_wise: Use .manage() callback instead of
 .throttle()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Make the Step-Wise governor use the new .manage() callback instead of
throttle().

Even though using .throttle() is not particularly problematic for the
Step-Wise governor, using .manage() instead still allows it to reduce
overhead by updating all of the colling devices once after setting
target values for all of the thermal instances.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/thermal/gov_step_wise.c |   39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

Index: linux-pm/drivers/thermal/gov_step_wise.c
===================================================================
--- linux-pm.orig/drivers/thermal/gov_step_wise.c
+++ linux-pm/drivers/thermal/gov_step_wise.c
@@ -109,34 +109,37 @@ static void thermal_zone_trip_update(str
 	}
 }
 
-/**
- * step_wise_throttle - throttles devices associated with the given zone
- * @tz: thermal_zone_device
- * @trip: trip point
- *
- * Throttling Logic: This uses the trend of the thermal zone to throttle.
- * If the thermal zone is 'heating up' this throttles all the cooling
- * devices associated with the zone and its particular trip point, by one
- * step. If the zone is 'cooling down' it brings back the performance of
- * the devices by one step.
- */
-static int step_wise_throttle(struct thermal_zone_device *tz,
-			      const struct thermal_trip *trip)
+static void step_wise_manage(struct thermal_zone_device *tz)
 {
+	const struct thermal_trip_desc *td;
 	struct thermal_instance *instance;
 
 	lockdep_assert_held(&tz->lock);
 
-	thermal_zone_trip_update(tz, trip);
+	/*
+	 * Throttling Logic: Use the trend of the thermal zone to throttle.
+	 * If the thermal zone is 'heating up', throttle all of the cooling
+	 * devices associated with each trip point by one step. If the zone
+	 * is 'cooling down', it brings back the performance of the devices
+	 * by one step.
+	 */
+	for_each_trip_desc(tz, td) {
+		const struct thermal_trip *trip = &td->trip;
+
+		if (trip->temperature == THERMAL_TEMP_INVALID ||
+		    trip->type == THERMAL_TRIP_CRITICAL ||
+		    trip->type == THERMAL_TRIP_HOT)
+			continue;
+
+		thermal_zone_trip_update(tz, trip);
+	}
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
 		thermal_cdev_update(instance->cdev);
-
-	return 0;
 }
 
 static struct thermal_governor thermal_gov_step_wise = {
-	.name		= "step_wise",
-	.throttle	= step_wise_throttle,
+	.name	= "step_wise",
+	.manage	= step_wise_manage,
 };
 THERMAL_GOVERNOR_DECLARE(thermal_gov_step_wise);