* IIO related heads up - on ARM64 you are likely to see DMA buffers being bounced soon...
@ 2023-06-09 17:08 Jonathan Cameron
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From: Jonathan Cameron @ 2023-06-09 17:08 UTC (permalink / raw)
To: linux-iio
Catalin's work to reduce the size of minimum allocation sizes
from kmalloc on ARM64 relies on a heuristic where small
buffers are always bounced to ensure DMA safety.
https://lore.kernel.org/all/20230531154836.1366225-1-catalin.marinas@arm.com/
Now this shouldn't break any IIO drivers but it might (at least in theory)
have a performance impact.
I'm curious on whether anyone cares enough about this?
Long term, if this approach ends up adopted on all architectures that
currently have ARCH_KMALLOC_MINALIGN set above 8 bytes we can get rid
of the explicit handling of DMA buffers in IIO as they will mostly be
bounced anyway - with the exception of a few that are bigger than the
relevant cacheline size.
Jonathan
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2023-06-09 17:08 IIO related heads up - on ARM64 you are likely to see DMA buffers being bounced soon Jonathan Cameron
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