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    SubjectRe: [patch 01/28] cpu alloc: The allocator
    Christoph Lameter a écrit :
    > On Tue, 13 Nov 2007, David Miller wrote:
    >
    >> One thing you could do is simply use a vmalloc allocation in the
    >> non-virtualized case.
    >
    > Yuck. Meaning to add more crappy code. The bss limitations to 8M is a bit
    > strange though. Do other platforms have the same issues?

    Maybe not so crappy, because even for i386 code, you might use not a strict
    vmalloc() implementation but at least reserving percpu space inside the
    vmalloc range. (ie not use a dedicated area as your current patchset does)

    This is because NR_CPUS is defaulted to 32 on i386 (with a limit of 256), so
    reserving 256*256KB = 64 MB of virtual space might be too much. (this is half
    the typical vmalloc area)

    The idea would be :

    - Reserving an area of NR_CPUS*256KB inside vmalloc() space (but of course not
    allocating pages)

    - Then for each non possible cpu, 'release' its 256KB area and give it back to
    vmalloc free areas pool.

    Once you add in mm/vmalloc.c all needed helpers, no need to use BSS Megablob
    anymore ?
    -
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