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

[Ingo Molnar]

* Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> 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
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