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    SubjectRe: [PATCH 2/3]: xvmalloc memory allocator
    On Tue, 17 Mar 2009, Nitin Gupta wrote:
    >> Creating slabs for sizes in range, say, [32, 3/4*PAGE_SIZE] separated by
    >> 64bytes
    >> will require 48 slabs! Then for slab of each size class will have wastage
    >> due to
    >> unused slab objects in each class.
    >> Larger difference in slab sizes (and thus small no. of them), will surely
    >> cause too much
    >> wastage due to internal fragmentation.

    On Tue, Mar 17, 2009 at 10:58 AM, Christoph Lameter
    <> wrote:
    > The slabs that match existing other slabs of similar sizes will be aliased
    > and not created. Create the 48 slabs and you likely will only use 10 real
    > additional ones. The rest will just be pointing to existing ones.

    Yup. One thing I don't quite understand is why you need all the 48
    caches in the first place. Allocation sizes tend to be clustered and I
    would have imagined you'd see that when compressing page sized chunks
    as well. Using kmemtrace to analyze the exact reason for the bad
    fragmentation would probably be helpful.

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      Last update: 2009-03-17 19:37    [W:0.021 / U:6.756 seconds]
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