[7/8] cpufreq: amd-pstate: Optimize amd_pstate_update_limits()

From: Mario Limonciello <mario.limonciello@amd.com>

Don't take and release the mutex when prefcore isn't present and
avoid initialization of variables that will be initially set
in the function.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

[AMD Official Use Only - AMD Internal Distribution Only]

> -----Original Message-----
> From: Mario Limonciello <superm1@kernel.org>
> Sent: Tuesday, August 27, 2024 5:14 AM
> To: Borislav Petkov <bp@alien8.de>; Shenoy, Gautham Ranjal
> <gautham.shenoy@amd.com>; Yuan, Perry <Perry.Yuan@amd.com>
> Cc: maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT) <x86@kernel.org>;
> Rafael J . Wysocki <rafael@kernel.org>; open list:X86 ARCHITECTURE (32-BIT
> AND 64-BIT) <linux-kernel@vger.kernel.org>; open list:ACPI <linux-
> acpi@vger.kernel.org>; open list:CPU FREQUENCY SCALING FRAMEWORK
> <linux-pm@vger.kernel.org>; Limonciello, Mario
> <Mario.Limonciello@amd.com>
> Subject: [PATCH 7/8] cpufreq: amd-pstate: Optimize
> amd_pstate_update_limits()
>
> From: Mario Limonciello <mario.limonciello@amd.com>
>
> Don't take and release the mutex when prefcore isn't present and avoid
> initialization of variables that will be initially set in the function.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 75568d0f84623..ed05d7a0add10 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -798,17 +798,17 @@ static void amd_pstate_update_limits(unsigned int
> cpu)
>       int ret;
>       bool highest_perf_changed = false;
>
> -     mutex_lock(&amd_pstate_driver_lock);
> -     if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
> -             goto free_cpufreq_put;
> +     if (!amd_pstate_prefcore)
> +             return;
>
> +     mutex_lock(&amd_pstate_driver_lock);
>       ret = amd_get_highest_perf(cpu, &cur_high);
>       if (ret)
>               goto free_cpufreq_put;
>
>       prev_high = READ_ONCE(cpudata->prefcore_ranking);
> -     if (prev_high != cur_high) {
> -             highest_perf_changed = true;
> +     highest_perf_changed = (prev_high != cur_high);
> +     if (highest_perf_changed) {
>               WRITE_ONCE(cpudata->prefcore_ranking, cur_high);
>
>               if (cur_high < CPPC_MAX_PERF)
> --
> 2.43.0
>

Reviewed-by: Perry Yuan <perry.yuan@amd.com>


Best Regards.

Perry.

On Mon, Aug 26, 2024 at 04:13:57PM -0500, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@amd.com>
> 
> Don't take and release the mutex when prefcore isn't present and
> avoid initialization of variables that will be initially set
> in the function.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
>  drivers/cpufreq/amd-pstate.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 75568d0f84623..ed05d7a0add10 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -798,17 +798,17 @@ static void amd_pstate_update_limits(unsigned int cpu)
>  	int ret;
>  	bool highest_perf_changed = false;
>  
> -	mutex_lock(&amd_pstate_driver_lock);
> -	if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
> -		goto free_cpufreq_put;
> +	if (!amd_pstate_prefcore)
> +		return;

Looks good to me.

Wondering if it is worth maintaining a static key for
amd_pstate_prefcore. Anyway it doesn't change after boot.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>


--
Thanks and Regards
gautham.

On 8/27/2024 11:57, Gautham R. Shenoy wrote:
> On Mon, Aug 26, 2024 at 04:13:57PM -0500, Mario Limonciello wrote:
>> From: Mario Limonciello <mario.limonciello@amd.com>
>>
>> Don't take and release the mutex when prefcore isn't present and
>> avoid initialization of variables that will be initially set
>> in the function.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> 
>> ---
>>   drivers/cpufreq/amd-pstate.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 75568d0f84623..ed05d7a0add10 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -798,17 +798,17 @@ static void amd_pstate_update_limits(unsigned int cpu)
>>   	int ret;
>>   	bool highest_perf_changed = false;
>>   
>> -	mutex_lock(&amd_pstate_driver_lock);
>> -	if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
>> -		goto free_cpufreq_put;
>> +	if (!amd_pstate_prefcore)
>> +		return;
> 
> Looks good to me.
> 
> Wondering if it is worth maintaining a static key for
> amd_pstate_prefcore. Anyway it doesn't change after boot.

As there is a kernel command line option how would you pass the early 
param parsing result over without a static variable?

> 
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
> 
Thanks!

> 
> --
> Thanks and Regards
> gautham.