Re: [PATCH v3] selftests/damon: test no-op commit broke DAMON status

[Sang-Heon Jeon <ekffu200098@gmail.com>]

On Sun, Aug 10, 2025 at 9:44 PM Sang-Heon Jeon <ekffu200098@gmail.com> wrote:
>
> Add test to verify that DAMON status is not changed after a no-op
> commit.
>
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
> ---

I just forgot to add change logs.

Changes from v1 [1]:
1. Fix code and commit message style.
2. Merge patch set into one patch.
3. Add fixes and cc section for backporting.

Changes from v2 [2]:
1. Separate the patch into two parts(code modifications and tests) And
this is part of test
2. Improve warning message on dump failure.

[1] https://lore.kernel.org/damon/20250808195518.563053-1-ekffu200098@gmail.com/
[2] https://lore.kernel.org/damon/20250809130756.637304-1-ekffu200098@gmail.com/

>  tools/testing/selftests/damon/Makefile        |  1 +
>  .../damon/sysfs_no_op_commit_break.py         | 72 +++++++++++++++++++
>  2 files changed, 73 insertions(+)
>  create mode 100755 tools/testing/selftests/damon/sysfs_no_op_commit_break.py
>
> diff --git a/tools/testing/selftests/damon/Makefile b/tools/testing/selftests/damon/Makefile
> index 5b230deb19e8..44a4a819df55 100644
> --- a/tools/testing/selftests/damon/Makefile
> +++ b/tools/testing/selftests/damon/Makefile
> @@ -17,6 +17,7 @@ TEST_PROGS += reclaim.sh lru_sort.sh
>  TEST_PROGS += sysfs_update_removed_scheme_dir.sh
>  TEST_PROGS += sysfs_update_schemes_tried_regions_hang.py
>  TEST_PROGS += sysfs_memcg_path_leak.sh
> +TEST_PROGS += sysfs_no_op_commit_break.py
>
>  EXTRA_CLEAN = __pycache__
>
> diff --git a/tools/testing/selftests/damon/sysfs_no_op_commit_break.py b/tools/testing/selftests/damon/sysfs_no_op_commit_break.py
> new file mode 100755
> index 000000000000..f557587ebc81
> --- /dev/null
> +++ b/tools/testing/selftests/damon/sysfs_no_op_commit_break.py
> @@ -0,0 +1,72 @@
> +#!/usr/bin/env python3
> +# SPDX-License-Identifier: GPL-2.0
> +
> +import json
> +import os
> +import subprocess
> +import sys
> +
> +import _damon_sysfs
> +
> +def dump_damon_status_dict(pid):
> +    try:
> +        subprocess.check_output(['which', 'drgn'], stderr=subprocess.DEVNULL)
> +    except:
> +        return None, 'drgn not found'
> +    file_dir = os.path.dirname(os.path.abspath(__file__))
> +    dump_script = os.path.join(file_dir, 'drgn_dump_damon_status.py')
> +    rc = subprocess.call(['drgn', dump_script, pid, 'damon_dump_output'],
> +        stderr=subprocess.DEVNULL)
> +
> +    if rc != 0:
> +        return None, f'drgn fail: return code({rc})'
> +    try:
> +        with open('damon_dump_output', 'r') as f:
> +            return json.load(f), None
> +    except Exception as e:
> +        return None, 'json.load fail (%s)' % e
> +
> +def main():
> +    kdamonds = _damon_sysfs.Kdamonds(
> +        [_damon_sysfs.Kdamond(
> +            contexts=[_damon_sysfs.DamonCtx(
> +                schemes=[_damon_sysfs.Damos(
> +                    ops_filters=[
> +                        _damon_sysfs.DamosFilter(
> +                            type_='anon',
> +                            matching=True,
> +                            allow=True,
> +                        )
> +                    ]
> +                )],
> +            )])]
> +    )
> +
> +    err = kdamonds.start()
> +    if err is not None:
> +        print('kdamond start failed: %s' % err)
> +        exit(1)
> +
> +    before_commit_status, err = \
> +        dump_damon_status_dict(kdamonds.kdamonds[0].pid)
> +    if err is not None:
> +        print('before-commit status dump failed: %s' % err)
> +        exit(1)
> +
> +    kdamonds.kdamonds[0].commit()
> +
> +    after_commit_status, err = \
> +        dump_damon_status_dict(kdamonds.kdamonds[0].pid)
> +    if err is not None:
> +        print('after-commit status dump failed: %s' % err)
> +        exit(1)
> +
> +    if before_commit_status != after_commit_status:
> +        print(f'before: {json.dump(before_commit_status, indent=2)}')
> +        print(f'after: {json.dump(after_commit_status, indent=2)}')
> +        exit(1)
> +
> +    kdamonds.stop()
> +
> +if __name__ == '__main__':
> +    main()
> --
> 2.43.0
>