linux-kernel - Re: [PATCH v4 03/19] cpufreq/amd-pstate: Drop min and max cached frequencies

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Message-ID: <2fed54f7-8e6a-4e33-ac4b-7a2a9c1387e6@amd.com>
Date: Mon, 24 Feb 2025 10:21:46 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: Mario Limonciello <superm1@...nel.org>,
 "Gautham R . Shenoy" <gautham.shenoy@....com>,
 Perry Yuan <perry.yuan@....com>
Cc: "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>,
 "open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
 Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v4 03/19] cpufreq/amd-pstate: Drop min and max cached
 frequencies

On 2/20/2025 2:32 AM, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> Use the perf_to_freq helpers to calculate this on the fly.
> As the members are no longer cached add an extra check into
> amd_pstate_update_min_max_limit().

Actually, we are adding the check in "amd_pstate_epp_update_limit" 
and we are adding it to avoid unnecessary calls to 
"amd_pstate_update_min_max_limit" if the cached limits are up to date.

Apart from that the patch looks good to me,

Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>

Thanks,
Dhananjay

> 
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> v4:
>  * Avoid some unnecessary changes to amd_pstate_init_freq()
>  * Add tag
> v3:
>  * Fix calc error for min_freq
> v2:
>  * Keep cached limits
> ---
>  drivers/cpufreq/amd-pstate-ut.c | 14 +++++------
>  drivers/cpufreq/amd-pstate.c    | 43 +++++++++------------------------
>  drivers/cpufreq/amd-pstate.h    |  9 ++-----
>  3 files changed, 20 insertions(+), 46 deletions(-)
> 
[Snip]> @@ -1550,7 +1528,8 @@ static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
>  	struct amd_cpudata *cpudata = policy->driver_data;
>  	u8 epp;
>  
> -	amd_pstate_update_min_max_limit(policy);
> +	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
> +		amd_pstate_update_min_max_limit(policy);
>  
>  	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
>  		epp = 0;
[Snip]