On 6/22/23 06:14, ypodemsk@redhat.com wrote:

I will send a new version with the local variable as you suggested
soon.
As for the config name, what about CONFIG_ARCH_HAS_MM_CPUMASK?

The confusing part about that name is that mm_cpumask() and
mm->cpu_bitmap[] are defined unconditionally.  So, they're *around*
unconditionally but just aren't updated.

BTW, it would also be nice to have _some_ kind of data behind this patch.

Fewer IPIs are better I guess, but it would still be nice if you could say:

	Before this patch, /proc/interrupts showed 123 IPIs/hour for an
	isolated CPU.  After the approach here, it was 0.

... or something.