Messages in this thread | | | Date | Fri, 08 Jan 2010 11:21:39 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 5/5] x86: update nr_irqs according cpu num |
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On 01/08/2010 11:11 AM, Eric W. Biederman wrote: > Yinghai Lu <yinghai@kernel.org> writes: > >> that is max number on run time. > > Ouch! Unless I misread this code this will leave nr_irqs at > NR_IRQS_LEGACY. aka 16. > > Let's do something stupid and simple. > nr_irqs = nr_cpus_ids * 256; /* Semi-arbitrary number */
This would be 1048576 on the biggest machines we currently support. Now, the number of IRQ *vectors* is limited to (224-system vectors)*(cpu count), so one could argue that if there is anything that is not semi-arbitrary it would be that number, but that doesn't account for vector sharing.
Do we have any place which requires nr_irqs to be *stable*, or can we simply treat it as a high water mark for IRQ numbers used?
> Ideally we would set "nr_irqs = 0x7fffffff;" but we have just enough > places using nr_irqs that I think those loops would get painful if we > were to do that.
Ideally we should presumably get rid of nr_irqs completely?
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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