Re: [RFC PATCH v5 mm-new 5/5] selftest/bpf: add selftest for BPF based THP order seletection

[Yafang Shao <laoar.shao@gmail.com>]

On Mon, Aug 18, 2025 at 10:00 PM Usama Arif <usamaarif642@gmail.com> wrote:
>
>
>
> On 18/08/2025 06:55, Yafang Shao wrote:
> > This self-test verifies that PMD-mapped THP allocation is restricted in
> > page faults for tasks within a specific cgroup, while still permitting
> > THP allocation via khugepaged.
> >
> > Since THP allocation depends on various factors (e.g., system memory
> > pressure), using the actual allocated THP size for validation is
> > unreliable. Instead, we check the return value of get_suggested_order(),
> > which indicates whether the system intends to allocate a THP, regardless of
> > whether the allocation ultimately succeeds.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> > ---
> >  tools/testing/selftests/bpf/config            |   3 +
> >  .../selftests/bpf/prog_tests/thp_adjust.c     | 224 ++++++++++++++++++
> >  .../selftests/bpf/progs/test_thp_adjust.c     |  76 ++++++
> >  .../bpf/progs/test_thp_adjust_failure.c       |  25 ++
> >  4 files changed, 328 insertions(+)
> >  create mode 100644 tools/testing/selftests/bpf/prog_tests/thp_adjust.c
> >  create mode 100644 tools/testing/selftests/bpf/progs/test_thp_adjust.c
> >  create mode 100644 tools/testing/selftests/bpf/progs/test_thp_adjust_failure.c
> >
>
> I think would be good to add selftests to make sure the bpf programs are working
> after fork/exec as intended.

Good suggestion. I will add a self test for it.

-- 
Regards
Yafang