linux-kernel - Re: [PATCH v1] cpufreq: preserve freq_table

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Message-ID: <CAJZ5v0iTR-0mbODbYPjbNcS-xx7AxF48ZtKrcqv--v_knY9xNg@mail.gmail.com>
Date: Mon, 20 Oct 2025 21:04:20 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: zzhwaxy <zhangzihuan@...inos.cn>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	zhenglifeng <zhenglifeng1@...wei.com>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] cpufreq: preserve freq_table_sorted across suspend/hibernate

On Sat, Oct 11, 2025 at 9:24 AM zzhwaxy <zhangzihuan@...inos.cn> wrote:
>
> From: Zihuan Zhang <zhangzihuan@...inos.cn>
>
> During S3/S4 suspend and resume, cpufreq policies are not freed or
> recreated; the freq_table and policy structure remain intact. However,
> set_freq_table_sorted() currently resets policy->freq_table_sorted to
> UNSORTED unconditionally, which is unnecessary since the table order
> does not change across suspend/resume.
>
> This patch adds a check to skip validation if policy->freq_table_sorted
> is already ASCENDING or DESCENDING. This avoids unnecessary traversal
> of the frequency table on S3/S4 resume or repeated online events,
> reducing overhead while preserving correctness.
>
> Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
> ---
>  drivers/cpufreq/cpufreq.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 852e024facc3..4a27f6cb07d3 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1421,9 +1421,12 @@ static int cpufreq_policy_online(struct cpufreq_policy *policy,
>                  * If there is a problem with its frequency table, take it
>                  * offline and drop it.
>                  */
> -               ret = cpufreq_table_validate_and_sort(policy);
> -               if (ret)
> -                       goto out_offline_policy;
> +               if (policy->freq_table_sorted != CPUFREQ_TABLE_SORTED_ASCENDING &&
> +                   policy->freq_table_sorted != CPUFREQ_TABLE_SORTED_DESCENDING) {
> +                       ret = cpufreq_table_validate_and_sort(policy);
> +                       if (ret)
> +                               goto out_offline_policy;
> +               }
>
>                 /* related_cpus should at least include policy->cpus. */
>                 cpumask_copy(policy->related_cpus, policy->cpus);
> --

Applied as 6.19 material, thanks!