On 2021-01-20 14:25, Björn Töpel wrote:
On 2021-01-20 13:52, Toke Høiland-Jørgensen wrote:
Björn Töpel <bjorn.topel@xxxxxxxxx> writes:
From: Björn Töpel <bjorn.topel@xxxxxxxxx>
Add detection for kernel version, and adapt the BPF program based on
kernel support. This way, users will get the best possible performance
from the BPF program.
Please do explicit feature detection instead of relying on the kernel
version number; some distro kernels are known to have a creative notion
of their own version, which is not really related to the features they
actually support (I'm sure you know which one I'm referring to ;)).
Right. For a *new* helper, like bpf_redirect_xsk, we rely on rejection
from the verifier to detect support. What about "bpf_redirect_map() now
supports passing return value as flags"? Any ideas how to do that in a
robust, non-version number-based scheme?
Just so that I understand this correctly. Red^WSome distro vendors
backport the world, and call that franken kernel, say, 3.10. Is that
interpretation correct? My hope was that wasn't the case. :-(
Would it make sense with some kind of BPF-specific "supported features"
mechanism? Something else with a bigger scope (whole kernel)?
Cheers,
Björn
