On Fri, Dec 15, 2023 at 08:37:59AM -0800, Jakub Kicinski wrote: > On Thu, 14 Dec 2023 13:31:38 -0800 Michael Chan wrote: > > From: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx> > > > > Remove double-mapping of DMA buffers as it can prevent page pool entries > > from being freed. Mapping is managed by page pool infrastructure and > > was previously managed by the driver in __bnxt_alloc_rx_page before > > allowing the page pool infrastructure to manage it. > > 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.
