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

Peter Zijlstra
2019-10-28T15:33:25Z

On Tue, Oct 22, 2019 at 04:34:24PM -0400, Thara Gopinath wrote:
> 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@linaro.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.

Uhm, this function doesn't have a @policy argument.

> + */
> +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;

check your types and ranges. What units is _freq in and does 'freq *
SCHED_CAPACITY' fit in 'unsigned int'? If so, why do you assign it to an
'unsigned long'?

> +
> + for_each_cpu(cpu, cpus)
> + update_thermal_pressure(cpu, capacity);
> +}

> @@ -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);

Codingstyle wants that in { }.

> +
> + return ret;
> }
>
> /**
> --
> 2.1.4
>