Messages in this thread | | | Date | Tue, 9 Apr 2024 15:47:56 +0100 | Subject | Re: [PATCH 1/2] PM: EM: Add min/max available performance state limits | From | Hongyan Xia <> |
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On 03/04/2024 17:23, Lukasz Luba wrote: > [...] > > diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c > index 927cc55ba0b3d..1a8b394251cb2 100644 > --- a/kernel/power/energy_model.c > +++ b/kernel/power/energy_model.c > @@ -628,6 +628,8 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, > goto unlock; > > dev->em_pd->flags |= flags; > + dev->em_pd->min_ps = 0; > + dev->em_pd->max_ps = nr_states - 1; > > em_cpufreq_update_efficiencies(dev, dev->em_pd->em_table->state); > > @@ -856,3 +858,49 @@ int em_dev_update_chip_binning(struct device *dev) > return em_recalc_and_update(dev, pd, em_table); > } > EXPORT_SYMBOL_GPL(em_dev_update_chip_binning); > + > + > +/** > + * em_update_performance_limits() - Update Energy Model with performance > + * limits information. > + * @pd : Performance Domain with EM that has to be updated. > + * @freq_min_khz : New minimum allowed frequency for this device. > + * @freq_max_khz : New maximum allowed frequency for this device. > + * > + * This function allows to update the EM with information about available > + * performance levels. It takes the minimum and maximum frequency in kHz > + * and does internal translation to performance levels. > + * Returns 0 on success or -EINVAL when failed. > + */ > +int em_update_performance_limits(struct em_perf_domain *pd, > + unsigned long freq_min_khz, unsigned long freq_max_khz) > +{ > + struct em_perf_state *table; > + int min_ps = -1; > + int max_ps = -1; > + int i; > + > + if (!pd) > + return -EINVAL; > + > + rcu_read_lock(); > + table = em_perf_state_from_pd(pd); > + > + for (i = 0; i < pd->nr_perf_states; i++) { > + if (freq_min_khz == table[i].frequency) > + min_ps = i; > + if (freq_max_khz == table[i].frequency) > + max_ps = i; > + } > + rcu_read_unlock(); > + > + /* Only update when both are found and sane */ > + if (min_ps < 0 || max_ps < 0 || max_ps < min_ps) > + return -EINVAL; > + > + pd->min_ps = min_ps; > + pd->max_ps = max_ps;
Are we sure we are protected against multiple simultaneous updates? Or is this a concern for the caller?
The rest of the patch LGTM.
> + > + return 0; > +} > +EXPORT_SYMBOL_GPL(em_update_performance_limits);
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