On Tue, Dec 05, 2023 at 08:00:48AM -0800, Yonghong Song wrote:
SNIP
> > > > +void test_tailcall_poke(void)
> > > > +{
> > > > + struct tailcall_poke *call, *test;
> > > > + int err, cnt = 10;
> > > > + pthread_t thread;
> > > > +
> > > > + unlink(JMP_TABLE);
> > > > +
> > > > + call = tailcall_poke__open_and_load();
> > > > + if (!ASSERT_OK_PTR(call, "tailcall_poke__open"))
> > > > + return;
> > > > +
> > > > + err = bpf_map__pin(call->maps.jmp_table, JMP_TABLE);
> > > > + if (!ASSERT_OK(err, "bpf_map__pin"))
> > > > + goto out;
> > > Just curious. What is the reason having bpf_map__pin() here
> > > and below? I tried and it looks like removing bpf_map__pin()
> > > and below bpf_map__set_pin_path() will make reproducing
> > > the failure hard/impossible.
> > yes, it's there to share the jmp_table map between the two
> > skeleton instances, so the update thread changes the same
> > jmp_table map that's used in the skeleton we load in the
> > while loop below
>
> This does make sense.
>
> >
> > I'll add some comments to the test
>
> Thanks for explanation. Some comments are definitely helpful!
np, also looks like I should move this to prog_tests/tailcalls.c,
will send new version with that
thanks,
jirka
>
> >
> > jirka
> >
> > > > +
> > > > + err = pthread_create(&thread, NULL, update, call);
> > > > + if (!ASSERT_OK(err, "new toggler"))
> > > > + goto out;
> > > > +
> > > > + while (cnt--) {
> > > > + test = tailcall_poke__open();
> > > > + if (!ASSERT_OK_PTR(test, "tailcall_poke__open"))
> > > > + break;
> > > > +
> > > > + err = bpf_map__set_pin_path(test->maps.jmp_table, JMP_TABLE);
> > > > + if (!ASSERT_OK(err, "bpf_map__pin")) {
> > > > + tailcall_poke__destroy(test);
> > > > + break;
> > > > + }
> > > > +
> > > > + bpf_program__set_autoload(test->progs.test, true);
> > > > + bpf_program__set_autoload(test->progs.call1, false);
> > > > + bpf_program__set_autoload(test->progs.call2, false);
> > > > +
> > > > + err = tailcall_poke__load(test);
> > > > + tailcall_poke__destroy(test);
> > > > + if (!ASSERT_OK(err, "tailcall_poke__load"))
> > > > + break;
> > > > + }
> > > > +
> > > > + thread_exit = 1;
> > > > + ASSERT_OK(pthread_join(thread, NULL), "pthread_join");
> > > > +
> > > > +out:
> > > > + bpf_map__unpin(call->maps.jmp_table, JMP_TABLE);
> > > > + tailcall_poke__destroy(call);
> > > > +}
> > SNIP
