Re: [PATCH bpf-next 8/8] selftests/bpf: Add tests for attaching bpf_link to netns

On Thu, May 28, 2020 at 08:08 AM CEST, Andrii Nakryiko wrote:

On Wed, May 27, 2020 at 12:16 PM Jakub Sitnicki [off-list ref] wrote:

quoted

Extend the existing test case for flow dissector attaching to cover:

 - link creation,
 - link updates,
 - link info querying,
 - mixing links with direct prog attachment.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---

You are not using bpf_program__attach_netns() at all. Would be nice to
actually use higher-level API here...

That's true. I didn't exercise the high-level API. I can cover that.

Also... what's up with people using CHECK_FAIL + perror instead of
CHECK? Is CHECK being avoided for some reason or people are just not
aware of it (which is strange, because CHECK was there before
CHECK_FAIL)?

I can only speak for myself. Funnily enough I think I've switched from
CHECK to CHECK_FAIL when I touched on BPF flow dissector last time [0].

CHECK needs and "external" duration variable to be in scope, and so it
was suggested to me that if I'm not measuring run-time with
bpf_prog_test_run, CHECK_FAIL might be a better choice.

CHECK is also perhaps too verbose because it emits a log message on
success (to report duration, I assume).

You have a better overview of all the tests than me, but if I had the
cycles I'd see if renaming CHECK to something more specific, for those
test that actually track prog run time, can work.

-jkbs


[0] https://lore.kernel.org/bpf/87imov1y5m.fsf@cloudflare.com/ (local)

quoted

 .../bpf/prog_tests/flow_dissector_reattach.c  | 500 +++++++++++++++++-
 1 file changed, 471 insertions(+), 29 deletions(-)

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