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    SubjectRe: [00/17] Large Blocksize Support V3
    On Sat, 28 Apr 2007 12:19:56 -0700 William Lee Irwin III <wli@holomorphy.com> wrote:

    > I'm skeptical, however, that the contiguity gains will compensate for
    > the CPU required to do such with the pcp lists.

    It wouldn't surprise me if approximate contiguity is a pretty common case
    in the pcp lists. Recaim isn't very important here: most pages get freed
    in truncate and particularly unmap_vmas. If the allocator is handing out
    pages in reasonably contiguous fashion (and it does, and we're talking
    about strengthening that) then I'd expect that very often we end up freeing
    pages which have a lot of locality too. So the sort of tricks which you're
    discussing might get a pretty good hit rate.

    otoh, it's not obvious to me that there's a lot to be gained here. If we
    repeatedly call the buddy allocator freeing contiguous order-0 pages, all
    the data structures which are needed to handle those should be in L1 cache
    and the buddy itself becomes our point-of-collection, if you see what I
    mean.

    Dunno. Profiling should tell?
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