From 47492d3667ec519172ab978bd8231b8c7152fa9d Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 5 Nov 2005 17:25:53 +0100 Subject: [PATCH] [PATCH] x86_64: Use the DMA32 zone for dma_alloc_coherent()/pci_alloc_consistent Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/pci-gart.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c index 88be97c96987..2e28e855ec3c 100644 --- a/arch/x86_64/kernel/pci-gart.c +++ b/arch/x86_64/kernel/pci-gart.c @@ -220,6 +220,12 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, uses the normal dma_mask for alloc_coherent. */ dma_mask &= *dev->dma_mask; + /* Why <=? Even when the mask is smaller than 4GB it is often larger + than 16MB and in this case we have a chance of finding fitting memory + in the next higher zone first. If not retry with true GFP_DMA. -AK */ + if (dma_mask <= 0xffffffff) + gfp |= GFP_DMA32; + again: memory = dma_alloc_pages(dev, gfp, get_order(size)); if (memory == NULL) @@ -245,7 +251,7 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, } if (!(gfp & GFP_DMA)) { - gfp |= GFP_DMA; + gfp = (gfp & ~GFP_DMA32) | GFP_DMA; goto again; } return NULL; -- 2.20.1