Messages in this thread | | | Date | Thu, 6 Aug 2009 21:15:27 +0100 | From | Jamie Lokier <> | Subject | Re: How to efficiently handle DMA and cache on ARMv7 ? (was "Is get_user_pages() enough to prevent pages from being swapped out ?") |
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David Xiao wrote: > Another approach is working from a different direction: the kernel > allocates the non-cached buffer and then mmap() into user space. I have > done that in similar situation to try to achieve "zero-copy".
open(O_DIRECT) does DMA to arbitrary pages allocated by userspace, and O_DIRECT is used by some important applications, so the problem still needs to be solved in general.
-- Jamie
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