On Wed, Nov 27, 2019 at 1:48 AM Jiri Olsa [off-list ref] wrote:

hi,
adding support to link bpftool with libbpf dynamically,
and config change for perf.

It's now possible to use:
  $ make -C tools/bpf/bpftool/ LIBBPF_DYNAMIC=1

which will detect libbpf devel package with needed version,
and if found, link it with bpftool.

It's possible to use arbitrary installed libbpf:
  $ make -C tools/bpf/bpftool/ LIBBPF_DYNAMIC=1 LIBBPF_DIR=/tmp/libbpf/

I based this change on top of Arnaldo's perf/core, because
it contains libbpf feature detection code as dependency.
It's now also synced with latest bpf-next, so Toke's change
applies correctly.

I don't like it.
Especially Toke's patch to expose netlink as public and stable libbpf api.
bpftools needs to stay tightly coupled with libbpf (and statically
linked for that reason).
Otherwise libbpf will grow a ton of public api that would have to be stable
and will quickly become a burden.