John Fastabend <john.fastabend@xxxxxxxxx> writes: > 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. Yay! Thank you for the review! Will reply to each of those... -Toke
