[PATCH 1/6] genirq: allow assigning affinity to present but not online CPUs

[Christoph Hellwig]

Hi Joe,

On Fri, Feb 03, 2017 at 08:58:09PM -0500, Joe Korty wrote:
> IIRC, some years ago I ran across a customer system where
> the #cpus_present was twice as big as #cpus_possible.
> 
> Hyperthreading was turned off in the BIOS so it was not
> entirely out of line for the extra cpus to be declared
> present, even though none of them would ever be available
> for use.

This sounds like a system we should quirk around instead of optimizing
for it.  Unless I totally misunderstand the idea behind cpu_possible
and cpu_present.