linux-kernel - Re: [PATCH v1 4/4] ACPI: processor: thermal: Update CPU cooling devices on cpufreq policy changes

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Message-ID: <f8c87ea7a1fd8f763ff4ccf3c43706ae43f81ede.camel@intel.com>
Date:   Tue, 7 Mar 2023 16:43:38 +0000
From:   "Zhang, Rui" <rui.zhang@...el.com>
To:     "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>
CC:     "srinivas.pandruvada@...ux.intel.com" 
        <srinivas.pandruvada@...ux.intel.com>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "Wang, Quanxian" <quanxian.wang@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v1 4/4] ACPI: processor: thermal: Update CPU cooling
 devices on cpufreq policy changes

On Fri, 2023-03-03 at 20:23 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> When a cpufreq policy appears or goes away, the CPU cooling devices
> for
> the CPUs covered by that policy need to be updated so that the new
> processor_get_max_state() value is stored as max_state and the
> statistics in sysfs are rearranged for each of them.
> 
> Do that accordingly in acpi_thermal_cpufreq_init() and
> acpi_thermal_cpufreq_exit().
> 
> Fixes: a365105c685c("thermal: sysfs: Reuse cdev->max_state")
> Reported-by: Wang, Quanxian <quanxian.wang@...el.com>
> Link: 
> https://lore.kernel.org/linux-pm/53ec1f06f61c984100868926f282647e57ecfb2d.camel@intel.com/
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/acpi/processor_thermal.c |   16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> Index: linux-pm/drivers/acpi/processor_thermal.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/processor_thermal.c
> +++ linux-pm/drivers/acpi/processor_thermal.c
> @@ -140,9 +140,14 @@ void acpi_thermal_cpufreq_init(struct cp
>  		ret = freq_qos_add_request(&policy->constraints,
>  					   &pr->thermal_req,
>  					   FREQ_QOS_MAX, INT_MAX);
> -		if (ret < 0)
> +		if (ret < 0) {
>  			pr_err("Failed to add freq constraint for CPU%d
> (%d)\n",
>  			       cpu, ret);
> +			continue;
> +		}
> +
> +		if (!IS_ERR(pr->cdev))
> +			thermal_cooling_device_update(pr->cdev);

Although thermal_cooling_device_update() handles "pr->cdev == NULL"
case, I think it is better to use !IS_ERR_OR_NULL() here.

thanks,
rui

>  	}
>  }
>  
> @@ -153,8 +158,13 @@ void acpi_thermal_cpufreq_exit(struct cp
>  	for_each_cpu(cpu, policy->related_cpus) {
>  		struct acpi_processor *pr = per_cpu(processors, cpu);
>  
> -		if (pr)
> -			freq_qos_remove_request(&pr->thermal_req);
> +		if (!pr)
> +			continue;
> +
> +		freq_qos_remove_request(&pr->thermal_req);
> +
> +		if (!IS_ERR(pr->cdev))
> +			thermal_cooling_device_update(pr->cdev);
>  	}
>  }
>  #else				/* ! CONFIG_CPU_FREQ */
> 
> 
>