6.16-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit e0423541477dfb684fbc6e6b5386054bc650f264 upstream.
The intel_pstate driver manages CPU capacity changes itself and it does not need an update of the capacity of all CPUs in the system to be carried out after registering a PD.
Moreover, in some configurations (for instance, an SMT-capable hybrid x86 system booted with nosmt in the kernel command line) the em_check_capacity_update() call at the end of em_dev_register_perf_domain() always fails and reschedules itself to run once again in 1 s, so effectively it runs in vain every 1 s forever.
To address this, introduce a new variant of em_dev_register_perf_domain(), called em_dev_register_pd_no_update(), that does not invoke em_check_capacity_update(), and make intel_pstate use it instead of the original.
Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms") Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.... Reported-by: Kenneth R. Crudup kenny@panix.com Tested-by: Kenneth R. Crudup kenny@panix.com Cc: 6.16+ stable@vger.kernel.org # 6.16+ Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cpufreq/intel_pstate.c | 4 ++-- include/linux/energy_model.h | 10 ++++++++++ kernel/power/energy_model.c | 29 +++++++++++++++++++++++++---- 3 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f366d35c5840..0d5d283a5429 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1034,8 +1034,8 @@ static bool hybrid_register_perf_domain(unsigned int cpu) if (!cpu_dev) return false;
- if (em_dev_register_perf_domain(cpu_dev, HYBRID_EM_STATE_COUNT, &cb, - cpumask_of(cpu), false)) + if (em_dev_register_pd_no_update(cpu_dev, HYBRID_EM_STATE_COUNT, &cb, + cpumask_of(cpu), false)) return false;
cpudata->pd_registered = true; diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 7fa1eb3cc823..61d50571ad88 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -171,6 +171,9 @@ int em_dev_update_perf_domain(struct device *dev, int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, const struct em_data_callback *cb, const cpumask_t *cpus, bool microwatts); +int em_dev_register_pd_no_update(struct device *dev, unsigned int nr_states, + const struct em_data_callback *cb, + const cpumask_t *cpus, bool microwatts); void em_dev_unregister_perf_domain(struct device *dev); struct em_perf_table *em_table_alloc(struct em_perf_domain *pd); void em_table_free(struct em_perf_table *table); @@ -350,6 +353,13 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, { return -EINVAL; } +static inline +int em_dev_register_pd_no_update(struct device *dev, unsigned int nr_states, + const struct em_data_callback *cb, + const cpumask_t *cpus, bool microwatts) +{ + return -EINVAL; +} static inline void em_dev_unregister_perf_domain(struct device *dev) { } diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index ea7995a25780..8df55397414a 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -552,6 +552,30 @@ EXPORT_SYMBOL_GPL(em_cpu_get); int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, const struct em_data_callback *cb, const cpumask_t *cpus, bool microwatts) +{ + int ret = em_dev_register_pd_no_update(dev, nr_states, cb, cpus, microwatts); + + if (_is_cpu_device(dev)) + em_check_capacity_update(); + + return ret; +} +EXPORT_SYMBOL_GPL(em_dev_register_perf_domain); + +/** + * em_dev_register_pd_no_update() - Register a perf domain for a device + * @dev : Device to register the PD for + * @nr_states : Number of performance states in the new PD + * @cb : Callback functions for populating the energy model + * @cpus : CPUs to include in the new PD (mandatory if @dev is a CPU device) + * @microwatts : Whether or not the power values in the EM will be in uW + * + * Like em_dev_register_perf_domain(), but does not trigger a CPU capacity + * update after registering the PD, even if @dev is a CPU device. + */ +int em_dev_register_pd_no_update(struct device *dev, unsigned int nr_states, + const struct em_data_callback *cb, + const cpumask_t *cpus, bool microwatts) { struct em_perf_table *em_table; unsigned long cap, prev_cap = 0; @@ -636,12 +660,9 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, unlock: mutex_unlock(&em_pd_mutex);
- if (_is_cpu_device(dev)) - em_check_capacity_update(); - return ret; } -EXPORT_SYMBOL_GPL(em_dev_register_perf_domain); +EXPORT_SYMBOL_GPL(em_dev_register_pd_no_update);
/** * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device