Re: [PATCH 0/2] cpufreq: governor: Apply limits with target_freq instead of policy->cur

["zhenglifeng (A)" <zhenglifeng1@huawei.com>]

On 3/12/2026 2:16 PM, Viresh Kumar wrote:
> On 10-03-26, 21:11, zhenglifeng (A) wrote:
>> I basically agree with what you said. But I have a little question. Do you
>> think the target freq should be updated when querying cpuinfo_cur_freq? I
>> think it should only be updated by governor or when limits changed.
> 
> I am not sure I understand the question. Where are we updating
> target-freq ? As far as cpuinfo_cur_freq goes, there is no need to
> make any changes when that is queried but..
> - cpufreq core caches the currently known freq as policy->cur and uses
>   it everywhere.
> - When cpuinfo_cur_freq is queried, we go and check with the hardware,
>   what the frequency is.
> - If a difference is found, we align policy->cur with that, given it
>   is still withing policy limits. That's all.
> 

When querying cpuinfo_cur_freq, based on the following call chain, the
target frequency will eventually be updated if policy->cur is out of
limits:

show_cpuinfo_cur_freq()
  __cpufreq_get()
    cpufreq_verify_current_freq()
      handle_update()
        refresh_frequency_limits()
          cpufreq_set_policy()
            cpufreq_governor_limits()
              cpufreq_dbs_governor_limits()
                cpufreq_policy_apply_limits()
                  __cpufreq_driver_target()

At least to me, it's strange that querying frequency would cause the
target frequency to be updated.