[Intel-wired-lan] [PATCH 00/11] XDP unaligned chunk placement support

[Jakub Kicinski]

On Thu, 27 Jun 2019 12:14:50 +0100, Laatz, Kevin wrote:
> On the application side (xdpsock), we don't have to worry about the user 
> defined headroom, since it is 0, so we only need to account for the 
> XDP_PACKET_HEADROOM when computing the original address (in the default 
> scenario).

That assumes specific layout for the data inside the buffer.  Some NICs
will prepend information like timestamp to the packet, meaning the
packet would start at offset XDP_PACKET_HEADROOM + metadata len..

I think that's very limiting.  What is the challenge in providing
aligned addresses, exactly?