[PATCH v1 net-next 02/15] net: Introduce direct data placement tcp offload

[David Ahern]

On 12/11/20 11:45 AM, Jakub Kicinski wrote:
> Ack, these patches are not exciting (to me), so I'm wondering if there
> is a better way. The only reason NIC would have to understand a ULP for
> ZC is to parse out header/message lengths. There's gotta be a way to
> pass those in header options or such...
> 
> And, you know, if we figure something out - maybe we stand a chance
> against having 4 different zero copy implementations (this, TCP,
> AF_XDP, netgpu) :(

AF_XDP is for userspace IP/TCP/packet handling.

netgpu is fundamentally kernel stack socket with zerocopy direct to
userspace buffers. Yes, it has more complications like the process is
running on a GPU, but essential characteristics are header / payload
split, a kernel stack managed socket, and dedicated H/W queues for the
socket and those are all common to what the nvme patches are doing. So,
can we create a common framework for those characteristics which enables
other use cases (like a more generic Rx zerocopy)?