Re: [PATCH v3 05/13] cpu/hotplug: Reserve CPUHP states for nohz_full and managed IRQ down-paths

On Thu, Jun 18 2026 at 18:06, Thomas Gleixner wrote:
> On Thu, Jun 18 2026 at 11:11, Jing Wu wrote:
>> Add CPUHP_AP_NO_HZ_FULL_DYING and CPUHP_AP_IRQ_AFFINITY_DYING to the
>> cpuhp_state enum.  These dying callbacks are invoked during CPU offline
>> before the tick is stopped, enabling clean tick handover and managed
>> IRQ migration when a CPU transitions between isolated and housekeeping
>> states.
>>
>> The existing CPUHP_AP_IRQ_AFFINITY_ONLINE already handles managed IRQ
>> restoration on CPU online.  The new dying callback completes the pair,
>> migrating managed interrupts away from the CPU before it goes down.
>
> What? They are migrated away today already when the CPU goes down unless
> the CPU is the last one in the affinity set of the interrupt. So why do
> you need a new step for something which already exists?

Aside of that these hotplug states are not used at all. So what is this
patch for?