linux-kernel - Re: [PATCH v1 10/10] cpufreq: Pass policy pointer to ->update

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]

Message-ID: <CAJZ5v0iMYSTnX9mkZb8aEmtbKxWOgsshNJ_AqnB9Mn27y8jzeQ@mail.gmail.com>
Date: Mon, 7 Apr 2025 20:48:26 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>, 
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc: Linux PM <linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, Mario Limonciello <mario.limonciello@....com>, 
	Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH v1 10/10] cpufreq: Pass policy pointer to ->update_limits()

On Fri, Mar 28, 2025 at 9:49 PM Rafael J. Wysocki <rjw@...ysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> Since cpufreq_update_limits() obtains a cpufreq policy pointer for the
> given CPU and reference counts the corresponding policy object, it may
> as well pass the policy pointer to the cpufreq driver's ->update_limits()
> callback which allows that callback to avoid invoking cpufreq_cpu_get()
> for the same CPU.
>
> Accordingly, redefine ->update_limits() to take a policy pointer instead
> of a CPU number and update both drivers implementing it, intel_pstate
> and amd-pstate, as needed.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Hi Srinivas,

If you have any concerns regarding this patch, please let me know
(note that it is based on the [05/10]).

> ---
>  drivers/cpufreq/amd-pstate.c   |    7 ++-----
>  drivers/cpufreq/cpufreq.c      |    2 +-
>  drivers/cpufreq/intel_pstate.c |   29 ++++++++++++++++++-----------
>  include/linux/cpufreq.h        |    2 +-
>  4 files changed, 22 insertions(+), 18 deletions(-)
>
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -821,19 +821,16 @@
>         schedule_work(&sched_prefcore_work);
>  }
>
> -static void amd_pstate_update_limits(unsigned int cpu)
> +static void amd_pstate_update_limits(struct cpufreq_policy *policy)
>  {
> -       struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
>         struct amd_cpudata *cpudata;
>         u32 prev_high = 0, cur_high = 0;
>         bool highest_perf_changed = false;
> +       unsigned int cpu = policy->cpu;
>
>         if (!amd_pstate_prefcore)
>                 return;
>
> -       if (!policy)
> -               return;
> -
>         if (amd_get_highest_perf(cpu, &cur_high))
>                 return;
>
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2741,7 +2741,7 @@
>                 return;
>
>         if (cpufreq_driver->update_limits)
> -               cpufreq_driver->update_limits(cpu);
> +               cpufreq_driver->update_limits(policy);
>         else
>                 cpufreq_policy_refresh(policy);
>  }
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1353,14 +1353,9 @@
>                 cpufreq_update_policy(cpu);
>  }
>
> -static bool intel_pstate_update_max_freq(struct cpudata *cpudata)
> +static void __intel_pstate_update_max_freq(struct cpufreq_policy *policy,
> +                                          struct cpudata *cpudata)
>  {
> -       struct cpufreq_policy *policy __free(put_cpufreq_policy);
> -
> -       policy = cpufreq_cpu_get(cpudata->cpu);
> -       if (!policy)
> -               return false;
> -
>         guard(cpufreq_policy_write)(policy);
>
>         if (hwp_active)
> @@ -1370,16 +1365,28 @@
>                         cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
>
>         refresh_frequency_limits(policy);
> +}
> +
> +static bool intel_pstate_update_max_freq(struct cpudata *cpudata)
> +{
> +       struct cpufreq_policy *policy __free(put_cpufreq_policy);
> +
> +       policy = cpufreq_cpu_get(cpudata->cpu);
> +       if (!policy)
> +               return false;
> +
> +       __intel_pstate_update_max_freq(policy, cpudata);
>
>         return true;
>  }
>
> -static void intel_pstate_update_limits(unsigned int cpu)
> +static void intel_pstate_update_limits(struct cpufreq_policy *policy)
>  {
> -       struct cpudata *cpudata = all_cpu_data[cpu];
> +       struct cpudata *cpudata = all_cpu_data[policy->cpu];
> +
> +       __intel_pstate_update_max_freq(policy, cpudata);
>
> -       if (intel_pstate_update_max_freq(cpudata))
> -               hybrid_update_capacity(cpudata);
> +       hybrid_update_capacity(cpudata);
>  }
>
>  static void intel_pstate_update_limits_for_all(void)
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -399,7 +399,7 @@
>         unsigned int    (*get)(unsigned int cpu);
>
>         /* Called to update policy limits on firmware notifications. */
> -       void            (*update_limits)(unsigned int cpu);
> +       void            (*update_limits)(struct cpufreq_policy *policy);
>
>         /* optional */
>         int             (*bios_limit)(int cpu, unsigned int *limit);
>
>
>
>