Re: [RFC PATCH v2.1 02/17] mm/damon/paddr: support PGIDLE_UNSET probe filter type

[SJ Park <sj@kernel.org>]

On Mon, 27 Jul 2026 14:52:42 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The newly added DAMON probe filter type DAMON_FILTER_TYPE_PGIDLE_UNSET is not exposed in the sysfs interface.
> --
> 
> --- Patch [2]: [RFC PATCH v2.1 02/17] mm/damon/paddr: support PGIDLE_UNSET probe filter type ---
> commit 67629d6971ecadd1e1c345f911e353e76f34b34f
> Author: SJ Park <sj@kernel.org>
> 
> mm/damon/paddr: support PGIDLE_UNSET probe filter type
> 
> This commit implements support for the DAMON_FILTER_TYPE_PGIDLE_UNSET probe
> filter type in the physical address space DAMON operations set.
> 
> > diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> > index 5a6a78054784a..199de1463fa06 100644
> > --- a/mm/damon/paddr.c
> > +++ b/mm/damon/paddr.c
> > @@ -132,6 +132,12 @@ static bool damon_pa_filter_match(struct damon_filter *filter,
> >  			matched = filter->memcg_id == mem_cgroup_id(memcg);
> >  		rcu_read_unlock();
> >  		break;
> > +	case DAMON_FILTER_TYPE_PGIDLE_UNSET:
> > +		if (!folio)
> > +			matched = false;
> > +		else
> > +			matched = damon_folio_young(folio);
> > +		break;
> 
> [Severity: Medium]
> Should this new filter type also be exposed in the sysfs interface?
> 
> Looking at damon_sysfs_filter_type_names in mm/damon/sysfs.c, it maps sysfs
> string inputs to DAMON probe filter types, but it doesn't seem to include
> an entry for DAMON_FILTER_TYPE_PGIDLE_UNSET:
> 
> mm/damon/sysfs.c:damon_sysfs_filter_type_names[] = {
> 	{
> 		.type = DAMON_FILTER_TYPE_ANON,
> 		.name = "anon",
> 	},
> 	{
> 		.type = DAMON_FILTER_TYPE_MEMCG,
> 		.name = "memcg",
> 	},
> };
> 
> Without this mapping, does this prevent userspace from accessing the newly
> added feature, since any attempt to configure it through sysfs would be
> rejected?

A later patch of this series does that.

> 
> >  	default:
> >  		break;
> >  	}
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260727143829.86236-1-sj@kernel.org?part=2


Thanks,
SJ