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

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Message-ID: <874irkw9k7.ffs@tglx>
Date: Mon, 27 Oct 2025 18:15:04 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: Ulf Hansson <ulf.hansson@...aro.org>, Ben Horgan <ben.horgan@....com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Mark Rutland
 <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>, Maulik Shah
 <quic_mkshah@...cinc.com>, Sudeep Holla <sudeep.holla@....com>, Daniel
 Lezcano <daniel.lezcano@...aro.org>, Vincent Guittot
 <vincent.guittot@...aro.org>, linux-pm@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] smp: Introduce a helper function to check for
 pending IPIs

On Tue, Oct 21 2025 at 12:08, Ulf Hansson wrote:

> On Mon, 20 Oct 2025 at 21:11, Ben Horgan <ben.horgan@....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.

cpus_peek_for_pending_ipis() perhaps?