DMA issues, part 2
Posted Jul 1, 2004 1:49 UTC (Thu) by simonl
Parent article: DMA issues, part 2
Thanks for yet another interesting article.
I do not understand why opportunistic allocation would not work: If a device needs a DMA buffer within 2^32 (or 2^29 for that matter), just try to allocate memory, see if the it falls within that range, if not free the memory again and return error. Or maybe try to move some lowmem pages to highmem first.
I see the point with ZONE_DMA, the first 16 MB could be allocated for other purposes very quickly, perhaps even locked pages. But is that really a problem with the entire 32 bit space?
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