Re: [PATCH 4/8] selftests/bpf: fix object files installation

From: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Jiri Benc <jbenc@redhat.com>,
	Jiri Olsa <jolsa@redhat.com>, Andrii Nakryiko <andriin@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [PATCH 4/8] selftests/bpf: fix object files installation
Date: Wed, 27 May 2020 08:17:48 +0300	[thread overview]
Message-ID: <xunyeer6ot1f.fsf@redhat.com> (raw)
In-Reply-To: <CAEf4BzZN=cMSFtinNOHMkDhposYPeHqgtJSwnpFSnQ2bX8BfyA@mail.gmail.com> (Andrii Nakryiko's message of "Tue, 26 May 2020 15:30:19 -0700")

Hi, Andrii!

>>>>> On Tue, 26 May 2020 15:30:19 -0700, Andrii Nakryiko  wrote:

 > On Thu, May 21, 2020 at 9:14 PM Yauheni Kaliuta
 > <yauheni.kaliuta@redhat.com> wrote:
 >> 
 >> There are problems with bpf test programs object files:
 >> 
 >> 1) some of them are build for flavored test runner and should be
 >> installed in the subdirectory;
 >> 2) it's possible that the same file mentioned several times (added
 >> for every different unflavored test runner);
 >> 3) some generated files are not treated properly.
 >> 
 >> Fix 1) by adding subdirectory to the list. rsync -a in the install
 >> target will handle it.
 >> 
 >> Fix 2) by filtering the list. Performance should not matter for such
 >> amount of files.
 >> 
 >> Fix 3) by use proper (TEST_GEN_FILES) variable for the list.
 >> 
 >> Fixes: 309b81f0fdc4 ("selftests/bpf: Install generated test progs")
 >> Fixes: e47a179997ce ("bpf, testing: Add missing object file to
 >> TEST_FILES")
 >> 
 >> Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
 >> ---
 >> tools/testing/selftests/bpf/Makefile | 9 ++++++---
 >> 1 file changed, 6 insertions(+), 3 deletions(-)
 >> 
 >> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
 >> index 19091dbc8ca4..1ba3d72c3261 100644
 >> --- a/tools/testing/selftests/bpf/Makefile
 >> +++ b/tools/testing/selftests/bpf/Makefile
 >> @@ -42,8 +42,7 @@ ifneq ($(BPF_GCC),)
 >> TEST_GEN_PROGS += test_progs-bpf_gcc
 >> endif
 >> 
 >> -TEST_GEN_FILES =
 >> -TEST_FILES = test_lwt_ip_encap.o \
 >> +TEST_GEN_FILES = test_lwt_ip_encap.o \
 >> test_tc_edt.o
 >> 
 >> BTF_C_FILES = $(wildcard progs/btf_dump_test_case_*.c)
 >> @@ -273,7 +272,11 @@ TRUNNER_BPF_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o, $$(TRUNNER_BPF_SRCS)
 >> TRUNNER_BPF_SKELS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.skel.h,      \
 >> $$(filter-out $(SKEL_BLACKLIST),       \
 >> $$(TRUNNER_BPF_SRCS)))
 >> -TEST_GEN_FILES += $$(TRUNNER_BPF_OBJS)
 >> +
 >> +TO_ADD := $(if $2,$$(TRUNNER_OUTPUT),$$(TRUNNER_BPF_OBJS))
 >> +$$(foreach i,$$(TO_ADD),\
 >> +       $$(eval \
 >> +               TEST_GEN_FILES += $$(if $$(filter $$i,$$(TEST_GEN_FILES)),,$$i)))

 > This makes me cringe. Can we not have three levels of nested
 > evals, please? I also didn't get exactly what's the problem
 > you are trying to solve, could you give some example, please?

It's sort of `unique` functionality.

With the current approach TEST_GEN_FILES has at least 2 copies of
an object file (for call test_progs and test_maps) which is both
inaccurate and increasing the length of the variable (even if
copying the same file should not cause problems).

(Without sub-directory handling it's even overwritten by
flavoured binaries in between).

BTW, how would you like to change $(call ...) with $(value ...)?
It will get rid of one level of indirection but requires
rule-specific variables for rule generation, since some
evaluations are done in recipies.

 >> 
 >> # Evaluate rules now with extra TRUNNER_XXX variables above already defined
 >> $$(eval $$(call DEFINE_TEST_RUNNER_RULES,$1,$2))
 >> --
 >> 2.26.2
 >> 

-- 
WBR,
Yauheni Kaliuta