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    SubjectRe: [PATCH 0/5] fix exhaustion of ZONE_DMA with swiotlb (in x86 tree)
    On Mon, Sep 08, 2008 at 06:10:09PM +0900, FUJITA Tomonori wrote:
    > This patchset (against tip/master) fixes the problem that swiotlb
    > exhausts ZONE_DMA:
    >
    > http://lkml.org/lkml/2008/8/31/16
    >
    > The root problem is that swiotlb_alloc_coherent always use ZONE_DMA,
    > which is fine for IA64 but not for x86_64.
    >
    > This patchset makes the callers set up the gfp flags so that
    > swiotlb_alloc_coherent can stop playing with the gfp flags.
    >
    > I think that it would be better to remove the allocation code in
    > swiotlb_alloc_coherent theoretically (what swiotlb should do is taking
    > care of the swiotlb memory. And swiotlb_alloc_coherent is not useful
    > since we use it only when we can't allocate memory reachable by the
    > device or we are in out of memory). But that code works for both x86
    > and IA64 so it's not so bad, I guess.
    >
    > #1 is for IA64, #2-4 for x86, and #5 is for swiotlb.

    Cool :-)

    This is much better than our last two tries to solve this problem. Doing
    no gfp handling at all in swiotlb_alloc_coherent is a nice and clean
    solution.

    Joerg

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