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    SubjectRe: x86: Convert cpu_core_map to be a per cpu variable
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    From: Christoph Lameter <clameter@sgi.com>
    Date: Thu, 12 Jul 2007 23:58:06 -0700 (PDT)

    > cpu_core_map is currently an array defined using NR_CPUS. This means that
    > we overallocate since we will rarely really use the maximum
    > number of configured cpus. This may become a problem when we need to
    > increase the NR_CPUs on x86_64 for our new product line.

    I'm using NR_CPUS set to 1024 on my sparc64 workstation, it's
    not that bad to be honest :-) What kind of cpu arity are you
    talking about?

    > If we put the cpu_core_map into the per cpu area then it will be allocated
    > for each processor as it comes online.
    >
    > However, this means that the core map cannot be accessed until the per cpu
    > area has been allocated. Xen does a weird thing here looping over all
    > processors and zeroing the masks that are not yet allocated and that will
    > be zeroed when they are allocated. I commented the code out. Maybe there
    > is another purpose? Jeremy?
    >
    > Signed-off-by: Christoph Lameter <clameter@sgi.com>

    Please take care of sparc64 if you're going to do this change.
    It uses cpu_core_map too.
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