Re: mutex vs. local irqs (Was: 2.6.18 -mm merge plans)

Ingo Molnar
2006-06-07T13:22:27Z

* Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> during boot). In addition to that, archs need to add something to their
> actual interrupt entry:
>
> if (no_irq_boot) {
> local_irq_disable();
> return;
> }

that just moves the suckage from the mutex-debugging slowpath to the
irq-handling hotpath. (at which point i still prefer to have that in the
mutex-debugging path)

a better solution would be to install boot-time IRQ vectors that just do
nothing but return. They dont mask, they dont ACK nor EOI - they just
return. The only thing that could break this is a screaming interrupt,
and even that one probably just slows things down a tiny bit until we
get so far in the init sequence to set up the PIC.

Ingo