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
>
>--
>2.53.0-Meta
>