[RFC PATCH 11/19] mm/damon/sysfs: implement filters directory

SeongJae Park
2026-04-26T20:52:38Z

Implement a directory for letting users to install data probe filters.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/sysfs.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 64 insertions(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index fac4e37aa2851..250208d3de21b 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -747,12 +747,42 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
.default_groups = damon_sysfs_intervals_groups,
};

+/*
+ * filters directory
+ */
+
+struct damon_sysfs_filters {
+ struct kobject kobj;
+};
+
+static struct damon_sysfs_filters *damon_sysfs_filters_alloc(void)
+{
+ return kzalloc_obj(struct damon_sysfs_filters);
+}
+
+static void damon_sysfs_filters_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_filters, kobj));
+}
+
+static struct attribute *damon_sysfs_filters_attrs[] = {
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_filters);
+
+static const struct kobj_type damon_sysfs_filters_ktype = {
+ .release = damon_sysfs_filters_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_filters_groups,
+};
+
/*
* probe directory
*/

struct damon_sysfs_probe {
struct kobject kobj;
+ struct damon_sysfs_filters *filters;
};

static struct damon_sysfs_probe *damon_sysfs_probe_alloc(void)
@@ -760,6 +790,30 @@ static struct damon_sysfs_probe *damon_sysfs_probe_alloc(void)
return kzalloc_obj(struct damon_sysfs_probe);
}

+static int damon_sysfs_probe_add_dirs(struct damon_sysfs_probe *attr)
+{
+ struct damon_sysfs_filters *filters;
+ int err;
+
+ filters = damon_sysfs_filters_alloc();
+ if (!filters)
+ return -ENOMEM;
+ attr->filters = filters;
+
+ err = kobject_init_and_add(&filters->kobj, &damon_sysfs_filters_ktype,
+ &attr->kobj, "filters");
+ if (err) {
+ kobject_put(&filters->kobj);
+ attr->filters = NULL;
+ }
+ return err;
+}
+
+static void damon_sysfs_probe_rm_dirs(struct damon_sysfs_probe *attr)
+{
+ kobject_put(&attr->filters->kobj);
+}
+
static void damon_sysfs_probe_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_probe, kobj));
@@ -797,8 +851,10 @@ static void damon_sysfs_probes_rm_dirs(
struct damon_sysfs_probe **probes_arr = probes->probes_arr;
int i;

- for (i = 0; i < probes->nr; i++)
+ for (i = 0; i < probes->nr; i++) {
+ damon_sysfs_probe_rm_dirs(probes_arr[i]);
kobject_put(&probes_arr[i]->kobj);
+ }
probes->nr = 0;
kfree(probes_arr);
probes->probes_arr = NULL;
@@ -836,6 +892,13 @@ static int damon_sysfs_probes_add_dirs(
return err;
}

+ err = damon_sysfs_probe_add_dirs(probe);
+ if (err) {
+ kobject_put(&probe->kobj);
+ damon_sysfs_probes_rm_dirs(probes);
+ return err;
+ }
+
probes_arr[i] = probe;
probes->nr++;
}
--
2.47.3