Re: [RFC][PATCH] irq_work

Peter Zijlstra
2010-06-24T10:30:42Z

On Thu, 2010-06-24 at 12:27 +0200, Andi Kleen wrote:
> > True, but I really don't like the softirq thing, and I really don't care
> > about !APIC machines, I probably couldn't buy one if I wanted to and its
> > not like we have good MCE support for them now, so who cares.
>
> In theory you can run a machine with good MCE support in non APIC single
> CPU mode. It wouldn't make much sense, but you could do it.
>
> Anyways, I don't think we need a lot of effort to handle this case,
> but it would be better to not explicitely break it either.
>
> That's why the timer fallback in the original code was fine, this
> basically never happens and even if there is a 5s delay from tickless
> that's fine.

Right, in that case I would very much prefer the simpler thing I
proposed over all this softirq stuff, we can have the tick process the
callbacks for really broken hardware (perf_events doesn't care since
without a lapic there's no pmi anyway).