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torvalds@transmeta.com said: > My personal opinion is that if a prefetch has semantic meanings > outside the "speed up subsequent accesses", it should not be exposed > to the rest of the kernel (it might still be useful inside > architecture-specific routines like optimized memcpy etc). Prefetch generally means 'bring it into the cache'. On architectures with non-cache-coherent DMA, doing a prefetch on wild address which happens to be a DMA buffer for which we've just said 'drop it from the cache' is generally a bad thing. Not that I'm necessarily disagreeing with you -- but can you confirm that you are including all architectures with non-cache-coherent DMA in the 'broken hardware' category below, or point out what I'm missing? > I'd rather speed up non-broken machines and let the broken hardware > hopefully slowly die away. -- dwmw2 - 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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