On Tue, May 11, 2010 at 11:48:36PM +0200, Johannes Weiner wrote: > On Tue, May 11, 2010 at 04:54:41PM -0400, Mike Frysinger wrote: > > does the phrase "DMA safe buffer" imply cache alignment ? > > I guess that depends on the architectural requirements. On x86, > apparently, not so much. On ARM, probably yes, as it's the > requirement to properly maintain coherency. It looks liek ARM (and a few others) do this: [dtor@hammer work]$ grep -r ARCH_KMALLOC_MINALIGN arch/ arch/sh/include/asm/page.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES arch/frv/include/asm/mem-layout.h:#define ARCH_KMALLOC_MINALIGN 8 arch/powerpc/include/asm/page_32.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES arch/arm/include/asm/cache.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES arch/microblaze/include/asm/page.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES arch/mips/include/asm/mach-tx49xx/kmalloc.h: * All happy, no need to define ARCH_KMALLOC_MINALIGN arch/mips/include/asm/mach-ip27/kmalloc.h: * All happy, no need to define ARCH_KMALLOC_MINALIGN arch/mips/include/asm/mach-ip32/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 32 arch/mips/include/asm/mach-ip32/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 128 arch/mips/include/asm/mach-generic/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 128 arch/avr32/include/asm/cache.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
