Re: [PATCH v3 4/5] cpufreq: qcom-cpufreq-hw: Use new thermal pressure update function

Thara Gopinath
2021-11-05T19:13:57Z

Hi Lukasz,

On 11/3/21 12:10 PM, Lukasz Luba wrote:
> Thermal pressure provides a new API, which allows to use CPU frequency
> as an argument. That removes the need of local conversion to capacity.
> Use this new API and remove old local conversion code.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> ---
> drivers/cpufreq/qcom-cpufreq-hw.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 0138b2ec406d..425f351450ad 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -275,10 +275,10 @@ static unsigned int qcom_lmh_get_throttle_freq(struct qcom_cpufreq_data *data)
>
> static void qcom_lmh_dcvs_notify(struct qcom_cpufreq_data *data)
> {
> - unsigned long max_capacity, capacity, freq_hz, throttled_freq;
> struct cpufreq_policy *policy = data->policy;
> int cpu = cpumask_first(policy->cpus);
> struct device *dev = get_cpu_device(cpu);
> + unsigned long freq_hz, throttled_freq;
> struct dev_pm_opp *opp;
> unsigned int freq;
>
> @@ -295,17 +295,12 @@ static void qcom_lmh_dcvs_notify(struct qcom_cpufreq_data *data)
>
> throttled_freq = freq_hz / HZ_PER_KHZ;
>
> - /* Update thermal pressure */
> -
> - max_capacity = arch_scale_cpu_capacity(cpu);
> - capacity = mult_frac(max_capacity, throttled_freq, policy->cpuinfo.max_freq);
> -
> /* Don't pass boost capacity to scheduler */
> - if (capacity > max_capacity)
> - capacity = max_capacity;

So, I think this should go into the common
topology_update_thermal_pressure in lieu of

+ if (WARN_ON(max_freq < capped_freq))
+ return;

This will fix the issue Steev Klimaszewski has been reporting
https://lore.kernel.org/linux-arm-kernel/3cba148a-7077-7b6b-f131-dc65045aa348@arm.com/

--
Warm Regards
Thara (She/Her/Hers)

> + if (throttled_freq > policy->cpuinfo.max_freq)
> + throttled_freq = policy->cpuinfo.max_freq;
>
> - arch_set_thermal_pressure(policy->related_cpus,
> - max_capacity - capacity);
> + /* Update thermal pressure */
> + arch_update_thermal_pressure(policy->related_cpus, throttled_freq);
>
> /*
> * In the unlikely case policy is unregistered do not enable