Re: [PATCH RFC 2/3] genirq: Honor existing IRQ affinities when setting affinity hints

On 2026-08-21 12:38:52 [+0200], Jan Kiszka wrote:
> Fully agree: drivers should not set affinities. They should just express
> desires or additional constraints. The ultimately resulting affinity for
> an IRQ should be the result of the various constraints that kernel and
> userland may express via NUMA placements, isolcpus, some dynamic
> isolation/grouping constraints, or you-name-it.

You might want to look at irq_create_affinity_masks()/
group_cpus_evenly() which attempts to spread irqs evenly across CPUs/
NUMA nodes. This is used by storage is considered a bit by the
isolcpus=managed_irq option.

> I think we need a big picture how things should eventually look like and
> then develop a strategy how to step-wise convert existing code.
> 
> Jan

Sebastian