Re: [PATCH dwarves] libbpf: allow to use packaged version

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Jan 15, 2021 at 03:40:34PM +0000, Luca Boccassi escreveu:
> On Fri, 2021-01-15 at 12:29 -0300, Arnaldo Carvalho de Melo wrote:
> > Em Mon, Jan 04, 2021 at 12:23:25PM -0800, Andrii Nakryiko escreveu:
> > > On Sun, Jan 3, 2021 at 1:30 PM Luca Boccassi <bluca@debian.org> wrote:
> > > > On Sun, 2021-01-03 at 11:10 -0800, Andrii Nakryiko wrote:
> > > > > On Sat, Jan 2, 2021 at 10:25 AM Luca Boccassi <bluca@debian.org>
> > > > > wrote:
> > > > > > Add a new CMake option, LIBBPF_EMBEDDED, to switch between the
> > > > > > embedded version and the system version (searched via pkg-config)
> > > > > > of libbpf. Set the system version as the default.
> > > > > > 
> > > > > 
> > > > > There's been a lot of arguments about libbpf as a submodule, so I
> > > > > don't think we need to go about pros and cons again, but I just
> > > > > wanted
> > > > > to cast my vote against doing this at all. Having pahole built with
> > > > > libbpf statically (only) was a great thing for me so far with
> > > > > iterating quickly and adopting new APIs without overcomplicating the
> > > > > source code with all sorts of feature detection code. Without it,
> > > > > adopting libbpf's faster string deduplication, BTF writing APIs,
> > > > > module/split BTFs, etc, etc, would be much bigger PITA and/or would
> > > > > prolong such changes. To the point that I personally wouldn't bother
> > > > > with some of them at all. Distro maintainers obviously don't care
> > > > > about such inconveniences for developers, but it's a real factor in
> > > > > determining what kind of functionality is implemented in pahole, so I
> > > > > hope Arnaldo won't dismiss this without thinking about this
> > > > > carefully.
> > 
> > Hey, having tools/perf/ and tools/lib/perf, tools/lib/bpf, etc all in
> > one place is really nice :-)
> > 
> > > > You know very well that it's not about caring or not caring :-) There
> > > > are simply conflicting interests, and both sides are valid.
> >  
> > > I didn't mean it in a negative way. Different priorities and interests
> > > is a better way to put it, sure.
> > 
> > I think the default should be submodules as we're still very much in
> > flux, adding new features, etc.
> > 
> > Disto maintainers can make sure they know what they're doing when making
> > tools use libbpf as a separate package.
> 
> Sure, v3 has the option as default-disabled already, not a problem at
> all.

Does this mean that if I have libbpf-devel installed in my system the
default build will _not_ link with it?

I have libbpf-devel installed in my machine but, by default, I _don't_
want pahole to build with it, libbpf-devel is there for other needs.

- Arnaldo