Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 9 Feb 2023 11:36:02 -0800 | Subject | Re: copy on write for splice() from file to pipe? |
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On Thu, Feb 9, 2023 at 11:17 AM Stefan Metzmacher <metze@samba.org> wrote: > > Any comment about the idea of having a preadv2() flag that > asks for a dma copy with something like async_memcpy() instead > of the default that ends up in copy_user_enhanced_fast_string()?
I guarantee that you will only slow things down with some odd async_memcpy.
There are zero DMA engines that do memory copying better than memcpy - the only way you can do better if is the destination isn't memory in the first place but the final device, and then we just call it "dma".
Linus
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