Toke Høiland-Jørgensen wrote: > This series adds support for transmitting packets using XDP in > bpf_prog_run(), by enabling the xdp_do_redirect() callback so XDP programs > can perform "real" redirects to devices or maps, using an opt-in flag when > executing the program. > > The primary use case for this is testing the redirect map types and the > ndo_xdp_xmit driver operation without generating external traffic. But it > turns out to also be useful for creating a programmable traffic generator. > The last patch adds a sample traffic generator to bpf/samples, which > can transmit up to 11.5 Mpps/core on my test machine. > > To transmit the frames, the new mode instantiates a page_pool structure in > bpf_prog_run() and initialises the pages with the data passed in by > userspace. These pages can then be redirected using the normal redirection > mechanism, and the existing page_pool code takes care of returning and > recycling them. The setup is optimised for high performance with a high > number of repetitions to support stress testing and the traffic generator > use case; see patch 6 for details. > > The series is structured as follows: Patches 1-2 adds a few features to > page_pool that are needed for the usage in bpf_prog_run(). Similarly, > patches 3-5 performs a couple of preparatory refactorings of the XDP > redirect and memory management code. Patch 6 adds the support to > bpf_prog_run() itself, patch 7 adds a selftest, and patch 8 adds the > traffic generator example to samples/bpf. Overall looks pretty good. Couple questions in the series though. Thanks! John
