Messages in this thread Patch in this message | | | Date | Fri, 30 Jul 2004 19:02:27 +0200 | From | Andi Kleen <> | Subject | [PATCH] Improve pci_alloc_consistent wrapper on preemptive kernels |
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This is a minor optimization for the pci_alloc_consistent wrapper for the generic dma API. When the kernel is compiled preemptive the caller can decide if the allocation needs to be GFP_KERNEL or GFP_ATOMIC.
I had this optimization previously in x86-64 private code, but it needs to move up now that x86-64 uses the generic DMA API.
diff -urpN -X ../KDIFX linux-2.6.8rc2-mm1/include/asm-generic/pci-dma-compat.h linux-2.6.8rc2-mm1-amd64/include/asm-generic/pci-dma-compat.h --- linux-2.6.8rc2-mm1/include/asm-generic/pci-dma-compat.h 2004-04-06 13:12:19.000000000 +0200 +++ linux-2.6.8rc2-mm1-amd64/include/asm-generic/pci-dma-compat.h 2004-07-30 17:02:49.000000000 +0200 @@ -5,6 +5,13 @@ #define _ASM_GENERIC_PCI_DMA_COMPAT_H #include <linux/dma-mapping.h> +#include <linux/config.h> + +#ifdef CONFIG_PREEMPT +#define preempt_atomic() in_atomic() +#else +#define preempt_atomic() 1 +#endif /* note pci_set_dma_mask isn't here, since it's a public function * exported from drivers/pci, use dma_supported instead */ @@ -15,11 +22,12 @@ pci_dma_supported(struct pci_dev *hwdev, return dma_supported(hwdev == NULL ? NULL : &hwdev->dev, mask); } +/* Would be better to move this out of line. It's already quite big. */ static inline void * pci_alloc_consistent(struct pci_dev *hwdev, size_t size, dma_addr_t *dma_handle) { - return dma_alloc_coherent(hwdev == NULL ? NULL : &hwdev->dev, size, dma_handle, GFP_ATOMIC); + return dma_alloc_coherent(hwdev == NULL ? NULL : &hwdev->dev, size, dma_handle, preempt_atomic() ? GFP_ATOMIC : GFP_KERNEL); } static inline void - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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