On 2020-05-20 21:33, Ming Lei wrote:
> No.
>
> If vector 3 is for covering hw queue 12 ~ 15, the vector shouldn't be
> shutdown when cpu 14 is offline.
>> Also I am pretty sure that we don't do this way with managed IRQ. And
> non-managed IRQ will be migrated to other online cpus during cpu offline,
> so not an issue at all. See migrate_one_irq().
Thanks for the pointer to migrate_one_irq().
However, I'm not convinced the above statement is correct. My
understanding is that the block driver knows which interrupt vector has
been associated with which hardware queue but the blk-mq core not. It
seems to me that patch 6/6 of this series is based on the following
assumptions:
(a) That the interrupt that is associated with a hardware queue is
processed by one of the CPU's in hctx->cpumask.
(b) That hardware queues do not share interrupt vectors.
I don't think that either assumption is correct.
Bart.
