On Wed, 1 Jun 2022 11:58:22 +0300 Maxim Mikityanskiy wrote:

quoted

For device offload only. Allow sendfile() data to be transmitted directly
to the NIC without making an in-kernel copy. This allows true zero-copy
behavior when device offload is enabled.  

I suggest mentioning the purpose of this optimization: a huge 
performance boost of up to 2.4 times compared to non-zerocopy device 
offload. See the performance numbers from my commit message:

That reads like and ad to me.