Weiping Zhang [off-list ref] writes:

nvme driver will add 4 sets for supporting NVMe weighted round robin,
and some of these sets may be empty(depends on user configuration),
so each particular set is assigned one static index for avoiding the
management trouble, then the empty set will be been by
irq_create_affinity_masks().

What's the point of an empty interrupt set in the first place? This does
not make sense and smells like a really bad hack.

Can you please explain in detail why this is required and why it
actually makes sense?

Thanks,

        tglx