Re: [PATCHv2 0/3] perf tools: Fix prologue generation

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Tue, May 24, 2022 at 1:28 AM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Mon, May 23, 2022 at 03:43:10PM -0700, Andrii Nakryiko wrote:
> > On Mon, May 23, 2022 at 12:49 AM Jiri Olsa <olsajiri@gmail.com> wrote:
> > >
> > > On Sat, May 21, 2022 at 02:44:05PM -0300, Arnaldo Carvalho de Melo wrote:
> > > > Em Fri, May 20, 2022 at 02:46:49PM -0700, Andrii Nakryiko escreveu:
> > > > > On Thu, May 19, 2022 at 4:03 AM Jiri Olsa <olsajiri@gmail.com> wrote:
> > > > > > On Wed, May 18, 2022 at 11:46:44AM +0200, Jiri Olsa wrote:
> > > > > > > On Tue, May 17, 2022 at 03:02:53PM -0700, Andrii Nakryiko wrote:
> > > > > > > > Jiri, libbpf v0.8 is out, can you please re-send your perf patches?
> > > >
> > > > > > > yep, just made new fedora package.. will resend the perf changes soon
> > > >
> > > > > > fedora package is on the way, but I'll need perf/core to merge
> > > > > > the bpf_program__set_insns change.. Arnaldo, any idea when this
> > > > > > could happen?
> > > >
> > > > > Can we land these patches through bpf-next to avoid such complicated
> > > > > cross-tree dependencies? As I started removing libbpf APIs I also
> > > > > noticed that perf is still using few other deprecated APIs:
> > > > >   - bpf_map__next;
> > > > >   - bpf_program__next;
> > > > >   - bpf_load_program;
> > > > >   - btf__get_from_id;
> > >
> > > these were added just to bypass the time window when they were not
> > > available in the package, so can be removed now (in the patch below)
> > >
> > > >
> > > > > It's trivial to fix up, but doing it across few trees will delay
> > > > > libbpf work as well.
> > > >
> > > > > So let's land this through bpf-next, if Arnaldo doesn't mind?
> > > >
> > > > Yeah, that should be ok, the only consideration is that I'm submitting
> > > > this today to Linus:
> > > >
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=tmp.perf/urgent&id=0ae065a5d265bc5ada13e350015458e0c5e5c351
> > > >
> > > > To address this:
> > > >
> > > > https://lore.kernel.org/linux-perf-users/f0add43b-3de5-20c5-22c4-70aff4af959f@scylladb.com/
> > >
> > > ok, we can do that via bpf-next, but of course there's a problem ;-)
> > >
> > > perf/core already has dependency commit [1]
> > >
> > > so either we wait for perf/core and bpf-next/master to sync or:
> > >
> > >   - perf/core reverts [1] and
> > >   - bpf-next/master takes [1] and the rest
> > >
> > > I have the changes ready if you guys are ok with that
> >
> > So, if I understand correctly, with merge window open bpf-next/master
> > will get code from perf/core soon when we merge tip back in. So we can
> > wait for that to happen and not revert anything.
> >
> > So please add the below patch to your series and resend once tip is
> > merged into bpf-next? Thanks!
>
> ok

Hm.. Ok, so I don't see your patches in tip yet. I see them in
perf/core only. Which means things won't happen naturally soon. How
should we proceed? I'm sitting on a pile of patches removing a lot of
code from libbpf and I'd rather get it out soon, but I can't because
of them breaking perf in bpf-next without Jiri's changes.

Arnaldo, what's your suggestion? Can we land remaining Jiri's patches
into perf/core and then you can create a tag for us to merge into
bpf-next, so that we avoid any conflicts later? Would that work? I
think we did something like that with other trees (e.g., RCU), when we
had dependencies like this before.

Thoughts?

>
> jirka