On Fri, 15 Dec 2023 11:57:14 -0500 Andy Gospodarek wrote: > > This patch is all good, but I'm confused by the handling of head. > > Do you recycle it immediately and hope that the Tx happens before > > the Rx gets around to using the recycled page again? Am I misreading? > > Your description is correct, but we use a better strategy that just > hoping it works out. :) > > The design is that we do not update the rx ring with the producer value > that was present when the packet was received until after getting the tx > completion indicating that the packet sent via XDP_TX action has been > sent. Ah, I see it, interesting! In that case - next question.. :) Are the XDP_REDIRECT (target) and XDP_TX going to the same rings? The locking seems to be missing, and bnxt_tx_int_xdp() does not seem to be able to handle the optimization you described if a ring contains a mix of XDP_REDIRECT and XDP_TX. If I'm reading the assignment in bnxt_alloc_mem() and indexing right - XDP_REDIRECT and XDP_TX do seem to go to the same rings.
