Re: [PATCH v9] cpufreq: powernv: Add sysfs attributes to show throttle stats

Viresh Kumar
2016-02-09T05:20:12Z

On 08-02-16, 20:14, Shilpasri G Bhat wrote:
> Create sysfs attributes to export throttle information in
> /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory. The
> newly added sysfs files are as follows:
>
> 1)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
> 2)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub-turbo_stat
> 3)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
> 4)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
> 5)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
> 6)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
> 7)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
> 8)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
>
> Detailed explanation of each attribute is added to
> Documentation/ABI/testing/sysfs-devices-system-cpu
>
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
> ---
> Changes from v8:
> - Moved the sysfs attributes from cpu/cpufreq/chipX to cpuX/cpufreq/throttle_stats
> - Adhering to one-value-per-file, replace throttle_table with multiple
> sysfs files.
> - Using CPUFREQ_POLICY_NOTIFIER to add/remove attribute_group.

Looks far better and sensible, but there are few bugs we have to fix
first.

> static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
> {
> struct powernv_smp_call_data freq_data;
> @@ -589,6 +694,7 @@ static int init_chip_info(void)
> }
>
> return 0;
> +

Unrelated change.

> free_chip_map:
> kfree(core_to_chip_map);
> out:
> @@ -615,6 +721,8 @@ static int __init powernv_cpufreq_init(void)
> if (rc)
> return rc;
>
> + cpufreq_register_notifier(&powernv_cpufreq_policy_nb,
> + CPUFREQ_POLICY_NOTIFIER);
> register_reboot_notifier(&powernv_cpufreq_reboot_nb);
> opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
> return cpufreq_register_driver(&powernv_cpufreq_driver);

If this fails, you don't unregister the notifiers. Actually, the BUG
is already there, and you must fix that first.

> @@ -626,6 +734,8 @@ static void __exit powernv_cpufreq_exit(void)
> unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
> opal_message_notifier_unregister(OPAL_MSG_OCC,
> &powernv_cpufreq_opal_nb);
> + cpufreq_unregister_notifier(&powernv_cpufreq_policy_nb,
> + CPUFREQ_POLICY_NOTIFIER);
> kfree(chips);
> kfree(core_to_chip_map);
> cpufreq_unregister_driver(&powernv_cpufreq_driver);

This is even more stupid. You remove the driver after freeing all
resources :)

Make this reverse of init..

Fix existing issues first and then apply this patch on the top.

--
viresh