Re: [PATCH bpf-next v3 5/7] tools/runqslower: Enable out-of-tree build

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, bpf <bpf@vger.kernel.org>,
	Martin Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	john fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>
Subject: Re: [PATCH bpf-next v3 5/7] tools/runqslower: Enable out-of-tree build
Date: Wed, 11 Nov 2020 10:23:52 -0800	[thread overview]
Message-ID: <CAEf4BzYbrxDi12Xz=Ti=CRxU5WGpwfJfCXUJ9JtYzRdu2=84Cw@mail.gmail.com> (raw)
In-Reply-To: <20201111085345.GA2604446@myrica>

On Wed, Nov 11, 2020 at 12:54 AM Jean-Philippe Brucker
<jean-philippe@linaro.org> wrote:
>
> On Tue, Nov 10, 2020 at 09:11:05PM -0800, Andrii Nakryiko wrote:
> > On Tue, Nov 10, 2020 at 8:46 AM Jean-Philippe Brucker
> > <jean-philippe@linaro.org> wrote:
> > >
> > > Enable out-of-tree build for runqslower. Only set OUTPUT=.output if it
> > > wasn't already set by the user.
> > >
> > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > > ---
> > > v3:
> > > * Drop clean recipe for bpftool and libbpf, since the whole output
> > >   directories are removed by the clean recipe.
> > > * Use ?= for $(OUTPUT)
> > > ---
> > >  tools/bpf/runqslower/Makefile | 32 ++++++++++++++++++--------------
> > >  1 file changed, 18 insertions(+), 14 deletions(-)
> > >
> >
> > [...]
> >
> > >  clean:
> > >         $(call QUIET_CLEAN, runqslower)
> > > -       $(Q)rm -rf $(OUTPUT) runqslower
> > > +       $(Q)$(RM) -r $(BPFOBJ_OUTPUT) $(BPFTOOL_OUTPUT)
> > > +       $(Q)$(RM) $(OUTPUT)*.o $(OUTPUT)*.d
> > > +       $(Q)$(RM) $(OUTPUT)*.skel.h $(OUTPUT)vmlinux.h
> > > +       $(Q)$(RM) $(OUTPUT)runqslower
> > > +       $(Q)$(RM) -r .output
> >
> > hard-coding .output here doesn't seem right, didn't all the other
> > lines clean up everything already?
>
> Yes, but to clean the source tree, the .output directory needs to be
> removed. On the other hand when $(OUTPUT) is out-of-tree, we only want to
> remove its content but not the dir itself, because it was created by the
> user.

Right, this is fine.

>
> Thanks,
> Jean
>
> >
> > >
> > >  $(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(BPFOBJ)
> > >         $(QUIET_LINK)$(CC) $(CFLAGS) $^ -lelf -lz -o $@
> > > @@ -59,8 +65,8 @@ $(OUTPUT)/%.bpf.o: %.bpf.c $(BPFOBJ) | $(OUTPUT)
> > >  $(OUTPUT)/%.o: %.c | $(OUTPUT)
> > >         $(QUIET_CC)$(CC) $(CFLAGS) $(INCLUDES) -c $(filter %.c,$^) -o $@
> > >
> >
> > [...]