On Thu, Dec 14, 2023 at 10:07 AM Lukasz Luba <lukasz.luba@xxxxxxx> wrote: > > On 12/14/23 07:57, Vincent Guittot wrote: > > On Thu, 14 Dec 2023 at 06:43, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote: > >> > >> On 12-12-23, 15:27, Vincent Guittot wrote: > >>> @@ -2618,6 +2663,9 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, > >>> policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H); > >>> trace_cpu_frequency_limits(policy); > >>> > >>> + cpus = policy->related_cpus; > >>> + cpufreq_update_pressure(cpus, policy->max); > >>> + > >>> policy->cached_target_freq = UINT_MAX; > >> > >> One more question, why are you doing this from cpufreq_set_policy ? If > >> due to cpufreq cooling or from userspace, we end up limiting the > >> maximum possible frequency, will this routine always get called ? > > > > Yes, any update of a FREQ_QOS_MAX ends up calling cpufreq_set_policy() > > to update the policy->max > > > > Agree, cpufreq sysfs scaling_max_freq is also important to handle > in this new design. Currently we don't reflect that as reduced CPU > capacity in the scheduler. There was discussion when I proposed to feed > that CPU frequency reduction into thermal_pressure [1]. > > The same applies for the DTPM which is missing currently the proper > impact to the CPU reduced capacity in the scheduler. > > IMHO any limit set into FREQ_QOS_MAX should be visible in this > new design of capacity reduction signaling. > > [1] https://lore.kernel.org/lkml/20220930094821.31665-2-lukasz.luba@xxxxxxx/ Actually, freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX) will return the requisite limit.
