Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 11 Feb 2019 11:56:37 +0100 | Subject | Re: [PATCH 1/2] cpufreq: Allow light-weight tear down on CPU offline operation |
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On Mon, Feb 11, 2019 at 11:51 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Mon, Feb 11, 2019 at 9:41 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > > > The cpufreq core doesn't remove the cpufreq policy anymore on CPU > > offline operation, rather that happens when the CPU device gets > > unregistered from the kernel. This allows faster recovery when the CPU > > comes back online. This is also very useful during system wide > > suspend/resume where we offline all non-boot CPUs during suspend and > > then bring them back on resume. > > > > This commit takes the same idea a step ahead to allow drivers to do > > light weight tear-down during CPU offline operation. > > > > A new callback is introduced, light_weight_exit(), which gets called > > when all the CPUs of a policy are removed/offlined and the existing > > exit() callback gets called when the policy gets freed. > > > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > > ---
[cut]
> > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > > index 9db074ecbbd7..36ce31516041 100644 > > --- a/include/linux/cpufreq.h > > +++ b/include/linux/cpufreq.h > > @@ -325,6 +325,7 @@ struct cpufreq_driver { > > /* optional */ > > int (*bios_limit)(int cpu, unsigned int *limit); > > > > + int (*light_weight_exit)(struct cpufreq_policy *policy); > > Can you call it "offline"? > > > int (*exit)(struct cpufreq_policy *policy); > > void (*stop_cpu)(struct cpufreq_policy *policy); > > int (*suspend)(struct cpufreq_policy *policy); > > --
Also, I would prefer a corresponding "online" callback to be there too for symmetry and I'd prefer the core to decide to call "online" instead of "init" for the light-weight case instead of ->init() itself having to figure out the context.
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