Hi Reviewers,
Just want to follow-up on this patch series. Please let me know the possible
issues and I will fix them.
Thanks very much!
Best,
Ziyang
On Fri, Aug 14, 2026 at 12:50:50AM -0700, Ziyang Men wrote:
This series re-factors the bpf-related toolchain for selftests, which
currently duplicated across selftests/{bpf,sched_ext,hid}/. Unify them
into a single includable fragment, the tools/testing/selftests/lib.bpf.mk,
and wires up three consumers. We believe this will simplify the work for
configuring selftests with the bpf, for both the existing and future ones.
Patch 1 adds lib.bpf.mk mentioned above.
Patch 2 adds a new selftest, selftests/cgroup/test_memcg_stat_cross_cpu,
which checks the cgroup flush happens correctly by comparing the bpf
read value matches the file reading. Existing test
bpf/cgroup_iter_memcg only ensures whether the number is non-zero, which
is trivial in some cases.
Patches 3 and 4 replace the duplicated parts in selftests/{hid,
sched_ext} with the lib.bpf.mk
===
Changes since v2:
For shared Makefile:
- The lib.bpf.mk now use the USERCFLAGS (and USERLDFLAGS) to extend the
CFLAGS and LDFLAGS.
- OPT_FLAGS/RELEASE and EXTRA_CFLAGS now reach the libbpf and bpftool
sub-makes as well.
- One rule per BPF source instead of a vpath, which is global and also
applied to the caller's own %.c rules.
- HOSTCC/HOSTLD come from lib.mk instead of including Makefile.include,
which also rewrote the caller's AR, LD and CFLAGS.
- A missing vmlinux is reported by the recipe rather than at parse time,
so "make clean" still works without BTF.
For cgroup selftest:
- Only one cgroup tree is created, one flush is performed, follows by
bpf read and file read.
- More common cgroup functions e.g., cg_read_key_long() and
value_close(), are used in the selftests.
- Use cpu_set_t rather than manually allocated cpu lists.
- Use test_memcontrol.c's anon allocator and moving it into cgroup_util.
- Other suggestion from the review.
Others:
- Bot reviews are fixed.
===
Changes since v1:
- Generalized lib.bpf.mk (source layout/suffix, extra hdrs/cflags,
skeleton suffix, subskeletons, configurable output dirs) so it can
serve hid and sched_ext, not just cgroup.
- Added patch 3 (hid) and patch 4 (sched_ext), converting those folders
to the shared fragment.
Ziyang Men (4):
selftests: add shared lib.bpf.mk to build BPF progs and skeletons
selftests/cgroup: add memcg_stat_cross_cpu correctness test for flush
selftests/hid: build the BPF program via the shared lib.bpf.mk
selftests/sched_ext: build BPF schedulers via the shared lib.bpf.mk
tools/testing/selftests/cgroup/.gitignore | 8 +
tools/testing/selftests/cgroup/Makefile | 52 ++
tools/testing/selftests/cgroup/config | 5 +
.../selftests/cgroup/lib/cgroup_util.c | 83 +++
.../cgroup/lib/include/cgroup_util.h | 3 +
.../cgroup/memcg_stat_cross_cpu.bpf.c | 86 +++
.../selftests/cgroup/memcg_stat_cross_cpu.h | 21 +
.../cgroup/test_memcg_stat_cross_cpu.c | 596 ++++++++++++++++++
.../selftests/cgroup/test_memcontrol.c | 29 +-
tools/testing/selftests/hid/.gitignore | 1 +
tools/testing/selftests/hid/Makefile | 180 +-----
tools/testing/selftests/lib.bpf.mk | 296 +++++++++
tools/testing/selftests/sched_ext/Makefile | 146 +----
13 files changed, 1204 insertions(+), 302 deletions(-)
create mode 100644 tools/testing/selftests/cgroup/memcg_stat_cross_cpu.bpf.c
create mode 100644 tools/testing/selftests/cgroup/memcg_stat_cross_cpu.h
create mode 100644 tools/testing/selftests/cgroup/test_memcg_stat_cross_cpu.c
create mode 100644 tools/testing/selftests/lib.bpf.mk
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2.53.0-Meta
