Re: [PATCH v1 05/10] cpufreq: intel_pstate: Rearrange max frequency updates handling code

Rafael J. Wysocki
2025-04-07T18:46:49Z

On Fri, Mar 28, 2025 at 9:58 PM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Rename __intel_pstate_update_max_freq() to intel_pstate_update_max_freq()
> and move the cpufreq policy reference counting and locking into it (and
> implement the locking with the recently introduced cpufreq policy "write"
> locking guard).
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Hi Srinivas,

If you have any concerns regarding this patch, please let me know.

> ---
> drivers/cpufreq/intel_pstate.c | 52 +++++++++++++----------------------------
> 1 file changed, 17 insertions(+), 35 deletions(-)
>
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1353,9 +1353,16 @@
> cpufreq_update_policy(cpu);
> }
>
> -static void __intel_pstate_update_max_freq(struct cpudata *cpudata,
> - struct cpufreq_policy *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;
> +
> + guard(cpufreq_policy_write)(policy);
> +
> if (hwp_active)
> intel_pstate_get_hwp_cap(cpudata);
>
> @@ -1363,44 +1370,24 @@
> cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
>
> refresh_frequency_limits(policy);
> +
> + return true;
> }
>
> static void intel_pstate_update_limits(unsigned int cpu)
> {
> - struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
> - struct cpudata *cpudata;
> -
> - if (!policy)
> - return;
> -
> - cpudata = all_cpu_data[cpu];
> -
> - __intel_pstate_update_max_freq(cpudata, policy);
> -
> - /* Prevent the driver from being unregistered now. */
> - mutex_lock(&intel_pstate_driver_lock);
> + struct cpudata *cpudata = all_cpu_data[cpu];
>
> - cpufreq_cpu_release(policy);
> -
> - hybrid_update_capacity(cpudata);
> -
> - mutex_unlock(&intel_pstate_driver_lock);
> + if (intel_pstate_update_max_freq(cpudata))
> + hybrid_update_capacity(cpudata);
> }
>
> static void intel_pstate_update_limits_for_all(void)
> {
> int cpu;
>
> - for_each_possible_cpu(cpu) {
> - struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
> -
> - if (!policy)
> - continue;
> -
> - __intel_pstate_update_max_freq(all_cpu_data[cpu], policy);
> -
> - cpufreq_cpu_release(policy);
> - }
> + for_each_possible_cpu(cpu)
> + intel_pstate_update_max_freq(all_cpu_data[cpu]);
>
> mutex_lock(&hybrid_capacity_lock);
>
> @@ -1840,13 +1827,8 @@
> {
> struct cpudata *cpudata =
> container_of(to_delayed_work(work), struct cpudata, hwp_notify_work);
> - struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
> -
> - if (policy) {
> - __intel_pstate_update_max_freq(cpudata, policy);
> -
> - cpufreq_cpu_release(policy);
>
> + if (intel_pstate_update_max_freq(cpudata)) {
> /*
> * The driver will not be unregistered while this function is
> * running, so update the capacity without acquiring the driver
>
>
>
>