Messages in this thread Patch in this message | | | Date | Wed, 10 Sep 2008 20:19:40 +0900 | Subject | [PATCH] x86: avoid unnecessary low zone allocation in AMD IOMMU's alloc_coherent | From | FUJITA Tomonori <> |
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This is for tip/iommu.
btw, Joery, what happens if map_sg (or map_single) gets not-DMA-capable buffer in the case of !iommu || !domain?
== From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Subject: [PATCH] x86: avoid unnecessary low zone allocation in AMD IOMMU's alloc_coherent
x86's common alloc_coherent (dma_alloc_coherent in dma-mapping.h) sets up the gfp flag according to the device dma_mask but AMD IOMMU doesn't need it for devices that the IOMMU can do virtual mappings for. This patch avoids unnecessary low zone allocation.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> --- arch/x86/kernel/amd_iommu.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 01c68c3..8efd249 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -999,6 +999,11 @@ static void *alloc_coherent(struct device *dev, size_t size, u16 devid; phys_addr_t paddr; + get_device_resources(dev, &iommu, &domain, &devid); + + if (iommu && domain) + flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); + virt_addr = (void *)__get_free_pages(flag, get_order(size)); if (!virt_addr) return 0; @@ -1006,8 +1011,6 @@ static void *alloc_coherent(struct device *dev, size_t size, memset(virt_addr, 0, size); paddr = virt_to_phys(virt_addr); - get_device_resources(dev, &iommu, &domain, &devid); - if (!iommu || !domain) { *dma_addr = (dma_addr_t)paddr; return virt_addr; -- 1.5.4.2
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