mm/damon/sysfs: implement probes dir

Implement sysfs directory that can be used by the users to install data
probes.

Link: https://lore.kernel.org/20260518234119.97569-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index d5863cc33d23032a85ca23ebd42228c9ea16922f..ccd19fc062f31c65c646ddd5bc784cf75d621d4a 100644 (file)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -747,6 +747,35 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
        .default_groups = damon_sysfs_intervals_groups,
 };
 
+/*
+ * probes directory
+ */
+
+struct damon_sysfs_probes {
+       struct kobject kobj;
+};
+
+static struct damon_sysfs_probes *damon_sysfs_probes_alloc(void)
+{
+       return kzalloc_obj(struct damon_sysfs_probes);
+}
+
+static void damon_sysfs_probes_release(struct kobject *kobj)
+{
+       kfree(container_of(kobj, struct damon_sysfs_probes, kobj));
+}
+
+static struct attribute *damon_sysfs_probes_attrs[] = {
+       NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_probes);
+
+static const struct kobj_type damon_sysfs_probes_ktype = {
+       .release = damon_sysfs_probes_release,
+       .sysfs_ops = &kobj_sysfs_ops,
+       .default_groups = damon_sysfs_probes_groups,
+};
+
 /*
  * monitoring_attrs directory
  */
@@ -755,6 +784,7 @@ struct damon_sysfs_attrs {
        struct kobject kobj;
        struct damon_sysfs_intervals *intervals;
        struct damon_sysfs_ul_range *nr_regions_range;
+       struct damon_sysfs_probes *probes;
 };
 
 static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
@@ -771,6 +801,7 @@ static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
 {
        struct damon_sysfs_intervals *intervals;
        struct damon_sysfs_ul_range *nr_regions_range;
+       struct damon_sysfs_probes *probes;
        int err;
 
        intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
@@ -799,8 +830,22 @@ static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
        if (err)
                goto put_nr_regions_intervals_out;
        attrs->nr_regions_range = nr_regions_range;
+
+       probes = damon_sysfs_probes_alloc();
+       if (!probes) {
+               err = -ENOMEM;
+               goto put_nr_regions_intervals_out;
+       }
+       err = kobject_init_and_add(&probes->kobj,
+                       &damon_sysfs_probes_ktype, &attrs->kobj, "probes");
+       if (err)
+               goto put_probes_out;
+       attrs->probes = probes;
        return 0;
 
+put_probes_out:
+       kobject_put(&probes->kobj);
+       attrs->probes = NULL;
 put_nr_regions_intervals_out:
        kobject_put(&nr_regions_range->kobj);
        attrs->nr_regions_range = NULL;
@@ -817,6 +862,7 @@ static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
        kobject_put(&attrs->nr_regions_range->kobj);
        damon_sysfs_intervals_rm_dirs(attrs->intervals);
        kobject_put(&attrs->intervals->kobj);
+       kobject_put(&attrs->probes->kobj);
 }
 
 static void damon_sysfs_attrs_release(struct kobject *kobj)