linux-kernel - Re: [PATCH] ACPI: update user_policy.max when

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 06 Jun 2013 08:27:08 +0800
From:	Joe Jin <joe.jin@...cle.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
CC:	Viresh Kumar <viresh.kumar@...aro.org>,
	Neil Gu <qing.gu@...cle.com>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI: update user_policy.max when _PPC updated

On 06/06/13 04:40, Rafael J. Wysocki wrote:
> On Wednesday, June 05, 2013 08:52:52 AM Joe Jin wrote:
>> When _PPC changed dynamically the user_policy.max will not be updated,
>> this prevent CPU run on the highest frequency.
> 
> Why should the user setting be always related to the current maximum available
> frequency?  What if the user sets the limit for power capping purposes?

cpufreq_update_policy() get policy->max from user_policy.max:

1782 int cpufreq_update_policy(unsigned int cpu)
1783 {
[...]
1800         policy.min = data->user_policy.min;
1801         policy.max = data->user_policy.max;
1802         policy.policy = data->user_policy.policy;
1803         policy.governor = data->user_policy.governor;
[...]
1819         ret = __cpufreq_set_policy(data, &policy);
[...]

/sys/devices/system/cpu/cpu$/cpufreq/scaling_max_freq using policy->max 
and user_policy->max, when update it, so I think _PPC changes also need
to update these two?

Thanks,
Joe
 
> 
> Rafael
> 
> 
>> Signed-off-by: Joe Jin <joe.jin@...cle.com>
>> Cc: Rafael J. Wysocki <rjw@...k.pl>
>> Cc: Viresh Kumar <viresh.kumar@...aro.org>
>> ---
>>  drivers/acpi/processor_perflib.c | 17 ++++++++++++++++-
>>  1 file changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
>> index e854582..e01aa7d 100644
>> --- a/drivers/acpi/processor_perflib.c
>> +++ b/drivers/acpi/processor_perflib.c
>> @@ -180,6 +180,7 @@ static void acpi_processor_ppc_ost(acpi_handle handle, int status)
>>  int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>>  {
>>  	int ret;
>> +	unsigned int saved = (unsigned int)pr->performance_platform_limit;
>>  
>>  	if (ignore_ppc) {
>>  		/*
>> @@ -204,8 +205,22 @@ int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>>  	}
>>  	if (ret < 0)
>>  		return (ret);
>> -	else
>> +	else {
>> +		unsigned int ppc = (unsigned int)pr->performance_platform_limit;
>> +
>> +		if (saved != ppc) {
>> +			struct cpufreq_policy *policy;
>> +
>> +			policy = cpufreq_cpu_get(pr->id);
>> +			if (likely(policy))
>> +				policy->user_policy.max =
>> +					pr->performance->states[ppc].
>> +					core_frequency * 1000;
>> +			cpufreq_cpu_put(policy);
>> +		}
>> +
>>  		return cpufreq_update_policy(pr->id);
>> +	}
>>  }
>>  
>>  int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
>>


-- 
Oracle <http://www.oracle.com>
Joe Jin | Software Development Senior Manager | +8610.6106.5624
ORACLE | Linux and Virtualization
No. 24 Zhongguancun Software Park, Haidian District | 100193 Beijing 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/