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

[sashiko-bot@kernel.org]

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?

>  	default:
>  		break;
>  	}

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