Re: [PATCH v9 09/13] isolation: Introduce io_queue isolcpus type

Sebastian Andrzej Siewior
2026-04-01T13:38:14Z

On 2026-03-30 18:10:43 [-0400], Aaron Tomlin wrote:
> From: Daniel Wagner <wagi@kernel.org>
>
> Multiqueue drivers spread I/O queues across all CPUs for optimal
> performance. However, these drivers are not aware of CPU isolation
> requirements and will distribute queues without considering the isolcpus
> configuration.
>
> Introduce a new isolcpus mask that allows users to define which CPUs
> should have I/O queues assigned. This is similar to managed_irq, but
> intended for drivers that do not use the managed IRQ infrastructure

I set down and documented the behaviour of managed_irq at
https://lore.kernel.org/all/20260401110232.ET5RxZfl@linutronix.de/

Could we please clarify whether we want to keep it and this
additionally or if managed_irq could be used instead. This adds another
bit. If networking folks jump in on managed_irqs, would they need to
duplicate this with their net sub flag?

> Reviewed-by: Hannes Reinecke <hare@suse.de>
> Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
> Signed-off-by: Daniel Wagner <wagi@kernel.org>

Sebastian