Re: [PATCH RESEND] smp: make wake up idle cpus more generic

[Daniel Lezcano]

On 04/02/2016 08:15 AM, Lianwei Wang wrote:
> > * Lianwei Wang <lianwei.wang@xxxxxxxxx> wrote:
> >
> > > The wake_up_all_idle_cpus API always wake up all the online
> > > cpus, but sometimes we only want to wake up a set of cpus.
> > > Use a generic function to wake up a group of cpus that is
> > > specified by the cpumask parameter. This generic API can
> > > benefit to the cases that only need to wake up a set of
> > > cpus.
> >
> > What is the new user of this new argument to the wake-up call?
> >
> > Thanks,
> >
> >          Ingo
>
> The ARM big.LITTLE arch is one of the users to use the new wake up
> call. Two clusters in these SoCs and each cluster has 2 or more CPUs.
> For some cases, we only need to wake up the cpus on one cluster, not
> all the cpus. The other cluster can keep in idle state to save power.
> Another use case is that for the threads/irqs that bind to some cpus,
> we also want to wake up the cpus that the threads/irqs bind to, and
> the other cpus can stay in idle state. I'm updating the pm_qos code to
> support binding the request to a set of cpus, and the
> cpuidle_latency_notify call can pass the cpumask parameter to the new
> wake-up call.

Hi Lianwei,

a quick suggestion : cpuidle_driver->cpumask

  -- Daniel


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