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    SubjectRe: [PATCH 2/4] x86, numa: Do not adjust start/end for early_node_mem()
    On Mon, Feb 21, 2011 at 10:43:18AM +0100, Tejun Heo wrote:
    > Hello,
    >
    > On Sat, Feb 19, 2011 at 08:17:11PM -0800, Yinghai Lu wrote:
    > > > The old code guarantees that the range is from a single zone, and even
    > > > though memblock may be top -> down, it seems like there would be
    > > > configurations where this would still be an issue (perhaps simulating it
    > > > with numa=fake for testing?) if it crosses the boundary.
    > >
    > > memblock_x86_find_in_range_node() will go over with early_node_map[].
    > > so it will always can get right on node allocation.
    >
    > I think always doing top-down allocation should be enough as long as
    > there's no highmem, which we don't have on 64bit. That said, the
    > patch description should note the behavior difference. Yinghai, care
    > to add a bit more detail to the patch description?

    Hmmm... thinking more about it, there actually is a difference.
    Depending on configuration, the new code allows node_data[] to be
    allocated below DMA boundary. I think we need to keep the first if().
    Areas crossing the boundaries is okay, in fact, the original code
    already allowed that when the NUMA affine allocation failed; however,
    node_data[] was never allowed below the DMA boundary and I think it
    shouldn't be.

    Thanks.

    --
    tejun


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