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    SubjectRe: Define CONFIG_BOUNCE to avoid useless inclusion of bounce buffer logic.
    Christoph Lameter writes:

    > > The DMA zone is for memory allocations _for_ _DMA_. If all your memory
    > > is DMA-able then it belongs in the DMA zone.
    >
    > Nope. The DMA zone is for crappy DMA devices that can only use a portion
    > of memory.

    That is (presumably) true today, but is in fact a redefinition of what
    ZONE_DMA historically was for.

    Also there is the problem that some drivers use ZONE_DMA allocations
    because their device can only generate addresses below some limit, but
    on a platform with an IOMMU there is in fact no restriction on what
    memory the device can access.

    Paul.
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