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

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]

Message-ID: <20191018082745.3zr6tc3yqmbydkrw@vireshk-i7>
Date:   Fri, 18 Oct 2019 13:57:45 +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, 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 and this explicitly checks

        if (policy->min > policy->max)
                policy->min = policy->max;

-- 
viresh