linux-kernel - Re: [PATCH 5/7] x86/tsc: Update cpufreq transition notifier to handle multiple CPUs

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Message-ID: <20190314100358.tpkianohhoxnfsmu@vireshk-i7>
Date:   Thu, 14 Mar 2019 15:33:58 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/7] x86/tsc: Update cpufreq transition notifier to
 handle multiple CPUs

On 14-03-19, 10:33, Rafael J. Wysocki wrote:
> On Thu, Mar 14, 2019 at 7:43 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > -               set_cyc2ns_scale(tsc_khz, freq->cpu, rdtsc());
> > +               if (boot_cpu) {
> > +                       boot_cpu_data.loops_per_jiffy = lpj;
> > +               } else {
> > +                       for_each_cpu(cpu, freq->cpus)
> 
> This needs to iterate over policy->cpus or you change the behavior.
> 
> Not that it will matter a lot (x86 in one CPU per policy anyway in the
> vast majority of cases), but it is a change nevertheless.  Moreover,
> I'm not even sure if doing that for offline CPUs makes sense.

Okay.

-- 
viresh