On Tue, 2021-06-01 at 13:32 +0200, Maciej Fijalkowski wrote: > Under rare circumstances there might be a situation where a > requirement > of having a XDP Tx queue per core could not be fulfilled and some of > the > Tx resources would have to be shared between cores. This yields a > need > for placing accesses to xdp_rings array onto critical section > protected > by spinlock. > > Design of handling such scenario is to at first find out how many > queues > are there that XDP could use. Any number that is not less than the > half > of a count of cores of platform is allowed. XDP queue count < cpu > count > is signalled via new VSI state ICE_VSI_XDP_FALLBACK which carries the > information further down to Rx rings where new ICE_TX_XDP_LOCKED is > set > based on the mentioned VSI state. This ring flag indicates that > locking > variants for getting/putting xdp_ring need to be used in fast path. > > For XDP_REDIRECT the impact on standard case (one XDP ring per CPU) > can > be reduced a bit by providing a separate ndo_xdp_xmit and swap it at > configuration time. However, due to the fact that net_device_ops > struct > is a const, it is not possible to replace a single ndo, so for the > locking variant of ndo_xdp_xmit, whole net_device_ops needs to be > replayed. > > It has an impact on performance (1-2 %) of a non-fallback path as > branches are introduced. > > Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx> > --- > drivers/net/ethernet/intel/ice/ice.h | 37 +++++++++ > drivers/net/ethernet/intel/ice/ice_base.c | 5 ++ > drivers/net/ethernet/intel/ice/ice_lib.c | 4 +- > drivers/net/ethernet/intel/ice/ice_main.c | 76 > ++++++++++++++++++- > drivers/net/ethernet/intel/ice/ice_txrx.c | 62 ++++++++++++++- > drivers/net/ethernet/intel/ice/ice_txrx.h | 2 + > drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 13 +++- > 7 files changed, 191 insertions(+), 8 deletions(-) This isn't applying to next-queue/dev-queue. I believe it's becuase the branch has the soon to be sent tracing patch from Magnus [1]. Thanks, Tony [1] https://patchwork.ozlabs.org/project/intel-wired- lan/patch/20210510093854.31652-3-magnus.karlsson@xxxxxxxxx/
