Jesper Dangaard Brouer <[email protected]> writes: > On 12/06/2025 12.54, Jesper Dangaard Brouer wrote: >> >> >> On 12/06/2025 12.30, Toke Høiland-Jørgensen wrote: >>> Steven Rostedt <[email protected]> writes: >>> >>>> From: Steven Rostedt <[email protected]> >>>> >>>> Each TRACE_EVENT() defined can take up around 5K of text and meta data >>>> regardless if they are used or not. New code is being developed that >>>> will >>>> warn when a tracepoint is defined but not used. >>>> >>>> The trace events xdp_redirect_map and xdp_redirect_map_err are >>>> defined but >>>> not used, but there's also a comment that states these are kept >>>> around for >>>> backward compatibility. Which is interesting because since they are not >>>> used, any old BPF program that expects them to exist will get incorrect >>>> data (no data) when they use them. It's worse than not working, it's >>>> silently failing. >>>> >>>> Remove them as they will soon cause warnings, or if they really need to >>>> stick around, then code needs to be added to use them. >>>> >>>> Signed-off-by: Steven Rostedt (Google) <[email protected]> >>> >>> I guess that makes sense; I have no objections to getting rid of them. >>> >>> Reviewed-by: Toke Høiland-Jørgensen <[email protected]> >> >> Make sense. >> >> >> Toke we have to check how XDP-tools handle when these tracepoints >> disappears. > > To Toke, notice that userspace tools expect this tracepoint to be > available will fail as below (for kernel release v6.16): > > $ sudo ./xdp-bench redirect mlx5p1 veth41 > libbpf: prog 'tp_xdp_redirect_map_err': failed to find kernel BTF > type ID of 'xdp_redirect_map_err': -3 > libbpf: prog 'tp_xdp_redirect_map_err': failed to prepare load > attributes: -3 > libbpf: prog 'tp_xdp_redirect_map_err': failed to load: -3 > libbpf: failed to load object 'xdp_redirect_basic' > Failed to attach XDP program: No such process > > IMHO this is a userspace problem, that needs to be more flexible and > adapt to this change. > > This was changed in kernel v5.6 (Jan 2020) commit 1d233886dd90 ("xdp: > Use bulking for non-map XDP_REDIRECT and consolidate code paths"). > So, I'm thinking that xdp-tools could just remove monitoring for these > tracepoints?
Yeah, let's just get rid of them: https://github.com/xdp-project/xdp-tools/pull/513 -Toke
