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    SubjectRe: [PATCH] percpu data: only iterate over possible CPUs

    On Tue, 7 Feb 2006, Eric Dumazet wrote:
    > This patch assumes that cpu_possible_map is setup before
    > setup_per_cpu_areas().
    > That sounds a reasonable assumption, but maybe not on your architecture ?

    I have to say, it sounds not just like a reasonable assumption, but like
    the only sane assumption that there _could_ be.

    > I dont think cpu_possible_map has to be filled at smp_prepare_cpus() time, but
    > long before.
    > On i386/x86_64/ia64, this is done from setup_arch() called from start_kernel()
    > just before setup_per_cpu_areas()
    > On powerpc it's done from setup_system(), called before start_kernel()

    It absolutely _has_ to be done from setup_arch() or earlier, as shown by
    the fact that "setup_per_cpu_areas()" is the very next thing that
    init/main.c calls (and clearly, that needs to know what CPU's are

    ppc64 certainly calls it early enough, as does x86/x86-64/ia64. I don't
    see anybody else doing it too late either.

    Heiko, can you point to the "old comment" you mentioned in the email, or
    the architecture that does this wrong?

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      Last update: 2009-11-18 23:46    [W:0.020 / U:12.128 seconds]
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