[PATCH] thermal/drivers/cpuidle_cooling: Make sure that idle_duration is larger than residency
From: <hidden>
Date: 2021-04-02 04:56:31
Also in:
lkml
Subsystem:
power management core, the rest, thermal, thermal/cpu_cooling · Maintainers:
"Rafael J. Wysocki", Linus Torvalds, Daniel Lezcano, Amit Daniel Kachhap, Viresh Kumar
From: Guangqing Zhu <redacted> The injected idle duration should be greater than the idle state min residency, otherwise we end up consuming more energy and potentially invert the mitigation effect. In function __cpuidle_cooling_register(), if of_property_read_u32(np, "exit-latency-us", &latency_us) is failed, then maybe we should not use latency_us. In this case, a zero latency_us for forced_idle_latency_limit_ns is better than UMAX_INT. It means to use governors in the usual way. Signed-off-by: Guangqing Zhu <redacted> --- drivers/powercap/idle_inject.c | 1 - drivers/thermal/cpuidle_cooling.c | 8 +++++++- 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index 6e1a0043c411..d76eef1e9387 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c@@ -309,7 +309,6 @@ struct idle_inject_device *idle_inject_register(struct cpumask *cpumask) cpumask_copy(to_cpumask(ii_dev->cpumask), cpumask); hrtimer_init(&ii_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); ii_dev->timer.function = idle_inject_timer_fn; - ii_dev->latency_us = UINT_MAX; for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {
diff --git a/drivers/thermal/cpuidle_cooling.c b/drivers/thermal/cpuidle_cooling.c
index 7ecab4b16b29..de770eb5b2ba 100644
--- a/drivers/thermal/cpuidle_cooling.c
+++ b/drivers/thermal/cpuidle_cooling.c@@ -175,7 +175,8 @@ static int __cpuidle_cooling_register(struct device_node *np, struct cpuidle_cooling_device *idle_cdev; struct thermal_cooling_device *cdev; unsigned int idle_duration_us = TICK_USEC; - unsigned int latency_us = UINT_MAX; + unsigned int latency_us = 0; + unsigned int residency_us = UINT_MAX; char dev_name[THERMAL_NAME_LENGTH]; int id, ret;
@@ -199,6 +200,11 @@ static int __cpuidle_cooling_register(struct device_node *np, of_property_read_u32(np, "duration-us", &idle_duration_us); of_property_read_u32(np, "exit-latency-us", &latency_us); + of_property_read_u32(np, "min-residency-us", &residency_us); + if (idle_duration_us <= residency_us) { + ret = -EINVAL; + goto out_unregister; + } idle_inject_set_duration(ii_dev, TICK_USEC, idle_duration_us); idle_inject_set_latency(ii_dev, latency_us);
--
2.17.1