lkml.org 
[lkml]   [2008]   [Sep]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH] swiotlb: fix dma_alloc_coherent allocation failures with swiotlb
    From
    On Thu, 4 Sep 2008 09:44:41 +0200
    Andi Kleen <andi@firstfloor.org> wrote:

    > On Thu, Sep 04, 2008 at 01:11:47PM +0900, FUJITA Tomonori wrote:
    > > On Thu, 04 Sep 2008 00:09:51 +0200
    > > Andi Kleen <andi@firstfloor.org> wrote:
    > >
    > > > Joerg Roedel <joerg.roedel@amd.com> writes:
    > > >
    > > > > The SWIOTLB version of dma_alloc_coherent allocates all memory with
    > > > > GFP_DMA unconditionally. This leads sometimes unnecessary to allocation
    > > > > failures. This patch makes the allocation strategy to use the DMA32 zone
    > > > > first if this is possible. The changes are boot tested on AMD64 and
    > > > > compile tested for i386 and IA64.
    > > >
    > > > The high level dma_alloc_coherent() does that anyways.
    > >
    > > The high level dma_alloc_coherent means the tricks in
    > > arch/x86/pci-dma.c? If so, all the tricks has gone in tip/master.
    >
    > Seems wrong -- that is something that is needed by multiple
    > IOMMUs. Pretty much all which work with real memory instead
    > of virtual mappings.

    Not all the IOMMUs need the old tricks used in arch/x86/pci-dma.c.

    The latest IOMMUs always need virtual mappings. They should handle
    dev->dma_mask properly like POWER IOMMU does (IIRC VT-d code does the
    right thing).


    \
     
     \ /
      Last update: 2008-09-04 10:01    [W:0.030 / U:31.932 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site