On Thu, Apr 12, 2018 at 03:50:29PM +0200, Jesper Dangaard Brouer wrote: > --------------- > Implement support for keeping the DMA mapping through the XDP return > call, to remove RX map/unmap calls. Implement bulking for XDP > ndo_xdp_xmit and XDP return frame API. Bulking allows to perform DMA > bulking via scatter-gatter DMA calls, XDP TX need it for DMA > map+unmap. The driver RX DMA-sync (to CPU) per packet calls are harder > to mitigate (via bulk technique). Ask DMA maintainer for a common > case direct call for swiotlb DMA sync call ;-) Why do you even end up in swiotlb code? Once you bounce buffer your performance is toast anyway..