Re: [RFC PATCH v1] btf: Sort BTF types by name and kind to optimize btf_find_by_name_kind lookup

[Andrii Nakryiko]

On Mon, Oct 13, 2025 at 4:53 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Mon, Oct 13, 2025 at 4:40 PM Andrii Nakryiko
> <andrii.nakryiko@xxxxxxxxx> wrote:
> >
> > Just a few observations (if we decide to do the sorting of BTF by name
> > in the kernel):
>
> iirc we discussed it in the past and decided to do sorting in pahole
> and let the kernel verify whether it's sorted or not.
> Then no extra memory is needed.
> Or was that idea discarded for some reason?

Don't really remember at this point, tbh. Pre-sorting should work
(though I'd argue that then we should only sort by name to make this
sorting universally useful, doing linear search over kinds is fast,
IMO). Pre-sorting won't work for program BTFs, don't know how
important that is. This indexing on demand approach would be
universal. ¯\_(ツ)_/¯

Overall, paying 300KB for sorted index for vmlinux BTF for cases where
we repeatedly need this seems ok to me, tbh.