Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> writes: > On Fri, Feb 28, 2020 at 6:22 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: >> >> Hi everyone >> >> As most of you are no doubt aware, we've had various discussions on how >> to handle multiple XDP programs on a single interface. With the freplace >> functionality, the kernel infrastructure is now there to handle this >> (almost, see "missing pieces" below). >> >> While the freplace mechanism offers userspace a lot of flexibility in >> how to handle dispatching of multiple XDP programs, userspace also has >> to do quite a bit of work to implement this (compared to just issuing >> load+attach). The goal of this email is to get some feedback on a >> library to implement this, in the hope that we can converge on something >> that will be widely applicable, ensuring that both (a) everyone doesn't >> have to reinvent the wheel, and (b) we don't end up with a proliferation >> of subtly incompatible dispatcher models that makes it hard or >> impossible to mix and match XDP programs from multiple sources. >> > > [...] > >> >> **** Missing pieces >> While the libxdp code can assemble a basic dispatcher and load it into the >> kernel, there are a couple of missing pieces on the kernel side; I will propose >> patches to fix these, but figured there was no reason to hold back posting of >> the library for comments because of this. These missing pieces are: >> >> - There is currently no way to persist the freplace after the program exits; the >> file descriptor returned by bpf_raw_tracepoint_open() will release the program >> when it is closed, and it cannot be pinned. > > This is completely addressed by patch set [0] I just posted. It will > allow you to pin freplace BPF link in BPF FS. Feel free to review and > comment there, if anything is missing. > > [0] > https://patchwork.ozlabs.org/project/netdev/list/?series=161582&state=* Ah, excellent! I'll take a look, thanks for the pointer :) -Toke
