Re: [External] Re: [PATCH bpf-next v2 7/9] libbpf: don't free btf if program of multi-link tracing existing

Alexei Starovoitov
2024-03-12T02:13:17Z

On Mon, Mar 11, 2024 at 7:05 PM 梦龙董 <dongmenglong.8@bytedance.com> wrote:
>
> > >
> > > +LIBBPF_API void bpf_object__free_btfs(struct bpf_object *obj);
> > > +
> >
> > It shouldn't be exported.
> > libbpf should clean it up when bpf_object is freed.
>
> Yes, libbpf will clean up the btfs when bpf_object is freed in
> this commit. And I'm trying to offer a way to early free the btfs
> by the users manual to reduce the memory usage. Or, the
> btfs that we opened will keep existing until we close the
> bpf_object.
>
> This is optional, I can remove it if you prefer.

Let's not extend libbpf api unless we really need to.
bpf_program__attach_trace_multi_opts() and
*skel*__attach() can probably free them.
I don't see a use case where you'd want to keep them afterwards.