linux-kernel - Re: [PATCH 10/15] cpufreq/amd-pstate: Move limit updating code

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Message-ID: <Z1MWD2gZR9NnGR5v@BLRRASHENOY1.amd.com>
Date: Fri, 6 Dec 2024 20:49:43 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Mario Limonciello <mario.limonciello@....com>
Cc: Perry Yuan <perry.yuan@....com>, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Subject: Re: [PATCH 10/15] cpufreq/amd-pstate: Move limit updating code

On Thu, Dec 05, 2024 at 04:28:42PM -0600, Mario Limonciello wrote:
> The limit updating code in amd_pstate_epp_update_limit() should not
> only apply to EPP updates.  Move it to amd_pstate_update_min_max_limit()
> so other callers can benefit as well.
> 
> With this move it's not necessary to have clamp_t calls anymore because
> the verify callback is called when setting limits.

Nice catch!!

The patch looks good to me.

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

--
Thanks and Regards
gautham.

> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 842e7e3c5eaf2..5ee53b45c1ca1 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -537,10 +537,6 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
>  	u32 nominal_perf = READ_ONCE(cpudata->nominal_perf);
>  	u64 value = prev;
>  
> -	min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
> -			cpudata->max_limit_perf);
> -	max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
> -			cpudata->max_limit_perf);
>  	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
>  
>  	max_freq = READ_ONCE(cpudata->max_limit_freq);
> @@ -616,11 +612,9 @@ static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
>  	min_limit_perf = div_u64(policy->min * max_perf, max_freq);
>  
>  	lowest_perf = READ_ONCE(cpudata->lowest_perf);
> -	if (min_limit_perf < lowest_perf)
> -		min_limit_perf = lowest_perf;
>  
> -	if (max_limit_perf < min_limit_perf)
> -		max_limit_perf = min_limit_perf;
> +	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> +		min_limit_perf = min(cpudata->nominal_perf, max_limit_perf);
>  
>  	WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
>  	WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
> @@ -1562,28 +1556,18 @@ static void amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
>  static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
>  {
>  	struct amd_cpudata *cpudata = policy->driver_data;
> -	u32 max_perf, min_perf;
>  	u64 value;
>  	s16 epp;
>  
> -	max_perf = READ_ONCE(cpudata->highest_perf);
> -	min_perf = READ_ONCE(cpudata->lowest_perf);
>  	amd_pstate_update_min_max_limit(policy);
>  
> -	max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
> -			cpudata->max_limit_perf);
> -	min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
> -			cpudata->max_limit_perf);
>  	value = READ_ONCE(cpudata->cppc_req_cached);
>  
> -	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> -		min_perf = min(cpudata->nominal_perf, max_perf);
> -
>  	value &= ~(AMD_PSTATE_MAX_PERF_MASK | AMD_PSTATE_MIN_PERF_MASK |
>  		   AMD_PSTATE_DES_PERF_MASK);
> -	value |= FIELD_PREP(AMD_PSTATE_MAX_PERF_MASK, max_perf);
> +	value |= FIELD_PREP(AMD_PSTATE_MAX_PERF_MASK, cpudata->max_limit_perf);
>  	value |= FIELD_PREP(AMD_PSTATE_DES_PERF_MASK, 0);
> -	value |= FIELD_PREP(AMD_PSTATE_MIN_PERF_MASK, min_perf);
> +	value |= FIELD_PREP(AMD_PSTATE_MIN_PERF_MASK, cpudata->min_limit_perf);
>  
>  	/* Get BIOS pre-defined epp value */
>  	epp = amd_pstate_get_epp(cpudata, value);
> -- 
> 2.43.0
>