Re: [RFC][PATCH v2 08/10] smp,irq_work: Use the new irq_work API

[Linus Torvalds]

On Wed, Aug 19, 2020 at 12:41 PM <peterz@xxxxxxxxxxxxx> wrote:
>
> I'm not sure I get the "expensive irq_work queues" argument, I fully
> agree with you that adding the atomic op is fairly crap.

There's an atomic op on the actual runing side too, because of the
whole IRQ_WORK_PENDING thing.

So you get that double hit.

Maybe it doesn't matter. I just remember us being very careful to
avoid any unnecessary atomics in the smp_call_function area, but
admittedly I haven't worked on that code for a few years, so ..

                Linus