linux-kernel - Re: v5.7: new core kernel option missing help text

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Message-ID: <20200603184500.GC1551@shell.armlinux.org.uk>
Date:   Wed, 3 Jun 2020 19:45:00 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Valentin Schneider <valentin.schneider@....com>
Cc:     Thara Gopinath <thara.gopinath@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: v5.7: new core kernel option missing help text

On Wed, Jun 03, 2020 at 07:00:26PM +0100, Valentin Schneider wrote:
> 
> On 03/06/20 18:31, Russell King - ARM Linux admin wrote:
> > Hi,
> >
> > A new kernel configuration option ("SCHED_THERMAL_PRESSURE") was
> > recently added, but has no help text. This is most unhelpful when
> > trying to configure the kernel, since one does not know what the
> > effect of answering yes or no to this option would be.
> >
> > Please supply a proper help text when adding core kernel options
> > so that people can make an informed decision when answering the
> > prompt, rather than just guessing.
> >
> 
> Right; does the below look good enough?

It's a start.  I'm still wondering whether I should answer yes or no
for the platforms I'm building for.

So far, all I've found is:

arch/arm/include/asm/topology.h:#define arch_scale_thermal_pressure topology_get_thermal_pressure

which really doesn't tell me anything about this.  So I'm still in
the dark.

I guess topology_get_thermal_pressure is provided by something in
drivers/ which will be conditional on some driver or something.

> 
> ---
> diff --git a/init/Kconfig b/init/Kconfig
> index 74a5ac65644f..f40cf852d00a 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -441,6 +441,10 @@ config HAVE_SCHED_AVG_IRQ
>  config SCHED_THERMAL_PRESSURE
>         bool "Enable periodic averaging of thermal pressure"
>         depends on SMP
> +	help
> +	  This option allows the scheduler to be aware of CPU thermal throttling
> +	  (i.e. thermal pressure), providing arch_scale_thermal_pressure() is
> +	  implemented.
> 
>  config BSD_PROCESS_ACCT
>         bool "BSD Process Accounting"
> ---
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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