Re: [RFC PATCH v2.1 5/7] mm/damon/sysfs-schemes: support probe_hits_wsum damos core filter

[SJ Park <sj@kernel.org>]

On Thu, 10 Sep 2026 04:18:33 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Low] The commit introduces `DAMOS_FILTER_TYPE_PROBE_HITS_WSUM` to the core layer and updates `damos_commit_filter_arg()` to properly copy its state (`range_min` and `range_max`), but fails to update the corresponding KUnit tests that rigorously check this exact behavior.
> --
> 
> commit 90fc8bb11dba04367743217a5b35954829f87d9c
> Author: SJ Park <sj@kernel.org>
> 
> mm/damon/sysfs-schemes: support probe_hits_wsum damos core filter
> 
> This commit extends the DAMON sysfs interface to support the probe_hits_wsum
> input for scheme core filters. It updates the scheme build logic to set up
> the min/max probe hits weighted sum range as provided by the user.
> 
> > diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
> > index 4d9147d2a269e..d9dd4ee0442c7 100644
> > --- a/mm/damon/sysfs-schemes.c
> > +++ b/mm/damon/sysfs-schemes.c
> 
> [ ... ]
> 
> > @@ -2844,6 +2847,14 @@ static int damon_sysfs_add_scheme_filters(struct damos *scheme,
> >  			}
> >  			filter->sz_range.min = sysfs_filter->range_min;
> >  			filter->sz_range.max = sysfs_filter->range_max;
> > +		} else if (filter->type = DAMOS_FILTER_TYPE_PROBE_HITS_WSUM) {
> > +			if (sysfs_filter->range_min >
> > +					sysfs_filter->range_max) {
> > +				damos_destroy_filter(filter);
> > +				return -EINVAL;
> > +			}
> > +			filter->range_min = sysfs_filter->range_min;
> > +			filter->range_max = sysfs_filter->range_max;
> 
> [Severity: Low]
> Does the addition of this new filter type require an update to the core
> KUnit tests?
> 
> In mm/damon/tests/core-kunit.h, there is a switch statement in
> damos_test_commit_filter_for() that checks parameter validation for each
> filter type:
> 
> 	switch (src->type) {
> 	case DAMOS_FILTER_TYPE_MEMCG:
> ...
> 	case DAMOS_FILTER_TYPE_HUGEPAGE_SIZE:
> 		KUNIT_EXPECT_EQ(test, dst->sz_range.min, src->sz_range.min);
> 		KUNIT_EXPECT_EQ(test, dst->sz_range.max, src->sz_range.max);
> 		break;
> 	default:
> 		break;
> 	}
> 
> Because DAMOS_FILTER_TYPE_PROBE_HITS_WSUM isn't handled here, it falls
> through to the default case, bypassing validation.
> 
> Additionally, the orchestrating function damos_test_commit_filter() doesn't
> appear to have a test block for this new type. Should these KUnit tests be
> updated to maintain test coverage for the new feature?

It would be good to add a test, but not necessarily together with this series.
I will consider adding such tests as a followup in future.

> 
> >  		}
> >  
> >  		damos_add_filter(scheme, filter);
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260910040319.147037-1-sj@kernel.org?part=5
> 


Thanks,
SJ