copy on write for splice() from file to pipe?
torvalds at linux-foundation.org
Thu Feb 9 19:36:02 UTC 2023
On Thu, Feb 9, 2023 at 11:17 AM Stefan Metzmacher <metze at 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".
More information about the samba-technical