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    SubjectRe: [patch 3/9] mempool - Make mempools NUMA aware
    Christoph Lameter wrote:
    > On Thu, 26 Jan 2006, Matthew Dobson wrote:
    >
    >
    >>Not all requests for memory from a specific node are performance
    >>enhancements, some are for correctness. With large machines, especially as
    >
    >
    > alloc_pages_node and friends do not guarantee allocation on that specific
    > node. That argument for "correctness" is bogus.

    alloc_pages_node() does not guarantee allocation on a specific node, but
    calling __alloc_pages() with a specific nodelist would.


    >>>You do not need this....
    >>
    >>I do not agree...
    >
    >
    > There is no way that you would need this patch.

    My goal was to not change the behavior of the slab allocator when inserting
    a mempool-backed allocator "under" it. Without support for at least
    *requesting* allocations from a specific node when allocating from a
    mempool, this would change how the slab allocator works. That would be
    bad. The slab allocator now does not guarantee that, for example, a
    kmalloc_node() request is satisfied by memory from the requested node, but
    it does at least TRY. Without adding mempool_alloc_node() then I would
    never be able to even TRY to satisfy a mempool-backed kmalloc_node()
    request from the correct node. I believe that would constitute an
    unacceptable breakage from normal, documented behavior. So, I *do* need
    this patch.

    -Matt
    -
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