Re: [PATCH 1/2] selftests/damon: test no-op commit broke DAMON status

[SeongJae Park <sj@kernel.org>]

On Sat, 9 Aug 2025 15:39:41 +0900 Sang-Heon Jeon <ekffu200098@gmail.com> wrote:

> Hi SeongJae
> 
> On Sat, Aug 9, 2025 at 7:05 AM SeongJae Park <sj@kernel.org> wrote:
> >
> > Hello Sang-Heon,
> >
> > On Sat,  9 Aug 2025 04:55:17 +0900 Sang-Heon Jeon <ekffu200098@gmail.com> wrote:
> >
> > > Add test to verify that DAMON status is not changed after a no-op
> > > commit.
> >
> > Thank you for this patch!  I have some comments below, though.
> >
> > > Currently, it is failing. but after fix the bug it should be
> > > success.
> >
> > To keep bisecting goes smoothly, let's introduce failing tests _after_ their
> > fixes are landed.
> 
> I see. As mentioned in another comment, I'll merge this patch set into
> one patch. I think this comment will be resolved then.

That could make the patch be unnecessarily difficult to apply on older kernels
due to the test part.  Please keep those separated.

[...]
> > > +    if rc != 0:
> > > +        return None, f'drgn fail : return code({rc})'
> >
> > Let's not add a space before ':', for the consistency.
> 
> I see. I made so many mistakes like these; (I worked this very late
> night...) I will fix them all. Thank you for checking this moment.

I'm sorry to hear that you had to work on late night :'(  I hope you to have
sufficient rests.

[...]
> To be honest, I didn't use kselftest framework while making these
> patch set because I don't know how kernel developers use it.
> 
> If you are okay, could you share how you use it?

Sure.  I do below for running DAMON selftests.

    $ sudo make -C tools/testing/selftests/damon run_tsets

You could also run DAMON kunit tests like below.

    $ ./tools/testing/kunit/kunit.py run --kunitconfig mm/damon/tests/

I usually run all those together with additional tests, using DAMON tests
suite[2].

> I just build kernel
> with custom patch, and execute output images by vm, and setup env,
> then just execute tests(it's so raw.. i know)

It's ok.  No one fits all, so different tests are needed for different hacks.
Please keep using whatever works best for you :)

> 
> Maybe is there a kernel build option that automatically includes tests
> to output image? Or just a general or smarter way to execute the whole
> test?

To be honest I'm also not an expert of kselftest and kunit :)  You coule refer
to the kselftest documentation[1] for more details.

[...]
> Thanks for reviewing! Have a nice weekend. I'll do this job after my
> personal schedule finishes.

No worry, take your time and fun! :)

[...]

[1] https://docs.kernel.org/dev-tools/kselftest.html
[2] https://github.com/damonitor/damon-tests/blob/master/corr/run.sh


Thanks,
SJ