Re: [RFC PATCH 13/19] mm/damon/sysfs: implement filter dir files

[Gutierrez Asier]

On 4/26/2026 11:52 PM, SeongJae Park wrote:
> Implement sysfs files under the data probe filter directory for letting
> users to configure each filter.
> 
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
> ---
>  mm/damon/sysfs.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 114 insertions(+)
> 
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index 25487a0268cbe..2e0b7eca6bcbf 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -753,6 +753,9 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
>  
>  struct damon_sysfs_filter {
>  	struct kobject kobj;
> +	enum damon_filter_type type;
> +	bool matching;
> +	bool allow;
>  };
>  
>  static struct damon_sysfs_filter *damon_sysfs_filter_alloc(void)
> @@ -760,6 +763,105 @@ static struct damon_sysfs_filter *damon_sysfs_filter_alloc(void)
>  	return kzalloc_obj(struct damon_sysfs_filter);
>  }
>  
> +struct damon_sysfs_filter_type_name {
> +	enum damon_filter_type type;
> +	char *name;
> +};
> +
> +static const struct damon_sysfs_filter_type_name
> +damon_sysfs_filter_type_names[] = {
> +	{
> +		.type = DAMON_TEST_TYPE_ANON,
> +		.name = "anon",
> +	},
> +};
> +
> +static ssize_t type_show(struct kobject *kobj,
> +		struct kobj_attribute *attr, char *buf)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(damon_sysfs_filter_type_names); i++) {
> +		const struct damon_sysfs_filter_type_name *type_name;
Can we move this declaration to the top of the function?
> +
> +		type_name = &damon_sysfs_filter_type_names[i];
> +		if (type_name->type == filter->type)
> +			return sysfs_emit(buf, "%s\n", type_name->name);
> +	}
> +	return -EINVAL;
> +}
> +
> +static ssize_t type_store(struct kobject *kobj,
> +		struct kobj_attribute *attr, const char *buf, size_t count)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +	ssize_t ret = -EINVAL;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(damon_sysfs_filter_type_names); i++) {
> +		const struct damon_sysfs_filter_type_name *type_name;
Same
> +
> +		type_name = &damon_sysfs_filter_type_names[i];
> +		if (sysfs_streq(buf, type_name->name)) {
> +			filter->type = type_name->type;
> +			ret = count;
> +			break;
> +		}
> +	}
> +	return ret;
> +}
> +
> +static ssize_t matching_show(struct kobject *kobj,
> +		struct kobj_attribute *attr, char *buf)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +
> +	return sysfs_emit(buf, "%c\n", filter->matching ? 'Y' : 'N');
> +}
> +
> +static ssize_t matching_store(struct kobject *kobj,
> +		struct kobj_attribute *attr, const char *buf, size_t count)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +	bool matching;
> +	int err = kstrtobool(buf, &matching);
> +
> +	if (err)
> +		return err;
> +
> +	filter->matching = matching;
> +	return count;
> +}
> +
> +static ssize_t allow_show(struct kobject *kobj,
> +		struct kobj_attribute *attr, char *buf)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +
> +	return sysfs_emit(buf, "%c\n", filter->allow ? 'Y' : 'N');
> +}
> +
> +static ssize_t allow_store(struct kobject *kobj,
> +		struct kobj_attribute *attr, const char *buf, size_t count)
> +{
> +	struct damon_sysfs_filter *filter = container_of(kobj,
> +			struct damon_sysfs_filter, kobj);
> +	bool allow;
> +	int err = kstrtobool(buf, &allow);
> +
> +	if (err)
> +		return err;
> +
> +	filter->allow = allow;
> +	return count;
> +}
> +
>  static void damon_sysfs_filter_release(struct kobject *kobj)
>  {
>  	struct damon_sysfs_filter *filter = container_of(kobj,
> @@ -768,7 +870,19 @@ static void damon_sysfs_filter_release(struct kobject *kobj)
>  	kfree(filter);
>  }
>  
> +static struct kobj_attribute damon_sysfs_filter_type_attr =
> +		__ATTR_RW_MODE(type, 0600);
> +
> +static struct kobj_attribute damon_sysfs_filter_matching_attr =
> +		__ATTR_RW_MODE(matching, 0600);
> +
> +static struct kobj_attribute damon_sysfs_filter_allow_attr =
> +		__ATTR_RW_MODE(allow, 0600);
> +
>  static struct attribute *damon_sysfs_filter_attrs[] = {
> +	&damon_sysfs_filter_type_attr.attr,
> +	&damon_sysfs_filter_matching_attr.attr,
> +	&damon_sysfs_filter_allow_attr.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(damon_sysfs_filter);

-- 
Asier Gutierrez
Huawei