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

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]

Date:   Thu, 4 Jun 2020 10:29:01 +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 <linux-kernel@...r.kernel.org>
Subject: Re: v5.7: new core kernel option missing help text

On Thu, Jun 04, 2020 at 10:26:27AM +0100, Valentin Schneider wrote:
> 
> On 04/06/20 01:48, Thara Gopinath wrote:
> > Hi Russel/Valentin
> >
> > The feature itself like Valentin explained below allows scheduler to be
> > aware of cpu capacity reduced due to thermal throttling.
> > arch_set_thermal_pressure feeds the capped capacity to the scheduler and
> > hence the feature makes sense only if arch_set_thermal_pressure is
> > implemented. Having said that arch_set_thermal_pressure is implemented
> > in arch_topology driver for arm and arm64 platforms. But the feature
> > itself is not bound to arm/arm64 platforms. So it would make it wrong to
> > add a "depends on (ARM || ARM64) option."
> >
> > I agree with Vincent that allowing user to choose this option is
> > probably not the best. IMO, this should be enabled by default in arm64
> > defconfig considering both GENERIC_ARCH_TOPOLOGY and CPU_FREQ_THERMAL
> > are enabled by default.
> 
> Right, I had skimmed over that but it probably does make more sense not
> to bother users with it.
> 
> > So if it is acceptable three things to be done are:
> > 1. Add the help text.
> > 2. Don't allow SCHED_THERMAL_PRESSURE configurable by user
> > 3. Enable it by default in arm64 defconfig
> 
> ... and arm as well, I suppose?

If it's not a user visible option, then there's no point it being in
defconfig.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up