Hi! This is a revival of Bjorn's idea [0] to break NAPI loop when XSK Rx queue gets full which in turn makes it impossible to keep on successfully producing descriptors to XSK Rx ring. By breaking out of the driver side immediately we will give the user space opportunity for consuming descriptors from XSK Rx ring and therefore provide room in the ring so that HW Rx -> XSK Rx redirection can be done. Maxim asked and Jesper agreed on simplifying Bjorn's original API used for detecting the event of interest, so let's just simply check for -ENOBUFS within Intel's ZC drivers after an attempt to redirect a buffer to XSK Rx. No real need for redirect API extension. One might ask why it is still relevant even after having proper busy poll support in place - here is the justification. For xdpsock that was: - run for l2fwd scenario, - app/driver processing took place on the same core in busy poll with 2048 budget, - HW ring sizes Tx 256, Rx 2048, this work improved throughput by 78% and reduced Rx queue full statistic bump by 99%. For testing ice, make sure that you have [1] present on your side. This set, besides the work described above, also carries also improvements around return codes in various XSK paths and lastly a minor optimization for xskq_cons_has_entries(), a helper that might be used when XSK Rx batching would make it to the kernel. Thanks! MF [0]: https://lore.kernel.org/bpf/20200904135332.60259-1-bjorn.topel@xxxxxxxxx/ [1]: https://lore.kernel.org/netdev/20220317175727.340251-1-maciej.fijalkowski@xxxxxxxxx/ Björn Töpel (1): xsk: improve xdp_do_redirect() error codes Maciej Fijalkowski (9): xsk: diversify return codes in xsk_rcv_check() ice: xsk: terminate NAPI when XSK Rx queue gets full i40e: xsk: terminate NAPI when XSK Rx queue gets full ixgbe: xsk: terminate NAPI when XSK Rx queue gets full ice: xsk: diversify return values from xsk_wakeup call paths i40e: xsk: diversify return values from xsk_wakeup call paths ixgbe: xsk: diversify return values from xsk_wakeup call paths ice: xsk: avoid refilling single Rx descriptors xsk: drop ternary operator from xskq_cons_has_entries .../ethernet/intel/i40e/i40e_txrx_common.h | 1 + drivers/net/ethernet/intel/i40e/i40e_xsk.c | 27 +++++++++------ drivers/net/ethernet/intel/ice/ice_txrx.h | 1 + drivers/net/ethernet/intel/ice/ice_xsk.c | 34 ++++++++++++------- .../ethernet/intel/ixgbe/ixgbe_txrx_common.h | 1 + drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 29 ++++++++++------ net/xdp/xsk.c | 4 +-- net/xdp/xsk_queue.h | 4 +-- 8 files changed, 64 insertions(+), 37 deletions(-) -- 2.33.1
