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    SubjectRe: [PATCH 5/5] x86: update nr_irqs according cpu num
    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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