linux-kernel - Re: [PATCH v1 06/13] thermal: gov_fair_share: Rearrange get_trip

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Message-ID: <3c9f7b7d-a9ca-79ae-4e64-367a82f953bc@linaro.org>
Date:   Wed, 27 Sep 2023 17:00:19 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Lukasz Luba <lukasz.luba@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH v1 06/13] thermal: gov_fair_share: Rearrange
 get_trip_level()

On 21/09/2023 19:54, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Make get_trip_level() access the thermal zone's trip table directly
> instead of using __thermal_zone_get_trip() which adds overhead related
> to the unnecessary bounds checking and copying the trip point data.
> 
> Also rearrange the code in it to make it somewhat easier to follow.
> 
> The general functionality is not expected to be changed.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>   drivers/thermal/gov_fair_share.c |   22 ++++++++++------------
>   1 file changed, 10 insertions(+), 12 deletions(-)
> 
> Index: linux-pm/drivers/thermal/gov_fair_share.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/gov_fair_share.c
> +++ linux-pm/drivers/thermal/gov_fair_share.c
> @@ -21,23 +21,21 @@
>    */
>   static int get_trip_level(struct thermal_zone_device *tz)
>   {
> -	struct thermal_trip trip;
> -	int count;
> +	const struct thermal_trip *trip = tz->trips;
> +	int i;
>   
> -	for (count = 0; count < tz->num_trips; count++) {
> -		__thermal_zone_get_trip(tz, count, &trip);
> -		if (tz->temperature < trip.temperature)
> +	if (tz->temperature < trip->temperature)
> +		return 0;
> +
> +	for (i = 0; i < tz->num_trips - 1; i++) {
> +		trip++;
> +		if (tz->temperature < trip->temperature)
>   			break;
>   	}

Is it possible to use for_each_thermal_trip() instead ? That would make 
the code more self-encapsulate

> -	/*
> -	 * count > 0 only if temperature is greater than first trip
> -	 * point, in which case, trip_point = count - 1
> -	 */
> -	if (count > 0)
> -		trace_thermal_zone_trip(tz, count - 1, trip.type);
> +	trace_thermal_zone_trip(tz, i, tz->trips[i].type);
>   
> -	return count;
> +	return i;
>   }
>   
>   static long get_target_state(struct thermal_zone_device *tz,
> 
> 
> 

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