linux-kernel - Re: [RFT][PATCH 0/3] cpufreq / PM: QoS: Introduce frequency QoS and use it in cpufreq

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Message-ID: <20191018092857.dfg6n3xcbdsfjr4r@vireshk-i7>
Date:   Fri, 18 Oct 2019 14:58:57 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Sudeep Holla <sudeep.holla@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Dmitry Osipenko <digetx@...il.com>
Subject: Re: [RFT][PATCH 0/3] cpufreq / PM: QoS: Introduce frequency QoS and
 use it in cpufreq

On 18-10-19, 11:26, Rafael J. Wysocki wrote:
> On Fri, Oct 18, 2019 at 11:24 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> >
> > On 18-10-19, 10:30, Rafael J. Wysocki wrote:
> > > On Fri, Oct 18, 2019 at 10:27 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > > >
> > > > On 18-10-19, 10:24, Rafael J. Wysocki wrote:
> > > > > On Fri, Oct 18, 2019 at 7:44 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > > > > >
> > > > > > On 17-10-19, 18:34, Rafael J. Wysocki wrote:
> > > > > > > [BTW, Viresh, it looks like cpufreq_set_policy() should still ensure
> > > > > > > that the new min is less than the new max, because the QoS doesn't do
> > > > > > > that.]
> > > > > >
> > > > > > The ->verify() callback does that for us I believe.
> > > > >
> > > > > It does in practice AFAICS, but in theory it may assume the right
> > > > > ordering between the min and the max and just test the boundaries, may
> > > > > it not?
> > > >
> > > > I think cpufreq_verify_within_limits() gets called for sure from
> > > > within ->verify() for all platforms
> > >
> > > That's why I mean by "in practice". :-)
> >
> > Hmm, I am not sure if we should really add another min <= max check in
> > cpufreq_set_policy() as in practice it will never hit :)
> 
> Fair enough, but adding a comment regarding that in there would be prudent IMO.

will do.

-- 
viresh