[PATCH v2 1/2] smp: Introduce a helper function to check for pending IPIs

[Ulf Hansson]

On Mon, 20 Oct 2025 at 21:11, Ben Horgan <ben.horgan at arm.com> wrote:
>
> Hi Ulf,
>
> Only a comment on the naming rather than a full review.
>
> On 10/20/25 15:17, Ulf Hansson wrote:
> > When governors used during cpuidle, tries to find the most optimal
> > idlestate for a CPU or a group of CPUs, they are known to quite often fail.
> > One reason for this, is that we are not taking into account whether there
> > has been an IPI scheduled for any of the CPUs that are affected by the
> > selected idlestate.
> >
> > To enable pending IPIs to be taken into account for cpuidle decisions,
> > let's introduce a new helper function, cpus_may_have_pending_ipi().
>
> To me, "may" indicates permission, i.e. is allowed, rather than
> correctness. Would "likely" be better here, cpus_likely_have_pending_ipi()?

Sure, that sounds better to me too.

I leave it a few days to allow people to provide their additional
input, before posting a new version with the new name of the function.

>
> >
> > Note that, the implementation is intentionally as lightweight as possible,
> > in favor of always providing the correct information. For cpuidle decisions
> > this is good enough.
> >
> > Suggested-by: Thomas Gleixner <tglx at linutronix.de>
> > Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
> > ---
> >
> > Changes in v2:
> >       - Implemented a common function, rather than making it arch-specific. As
> >       suggested by Thomas and Marc.
> >       - Renamed the function to indicate that it doesn't provide correctness.
> >       - Clarified function description and commit message.
> >
> --
> Thanks,
>
> Ben
>

Kind regards
Uffe