Implement sysfs directory for showing per-probe hits count of each
region.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 101 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 95 insertions(+), 6 deletions(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index b2dcbdf1840e4..91d6ddcf1b32d 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -10,12 +10,40 @@
 
 #include "sysfs-common.h"
 
+/*
+ * probe directory
+ */
+
+struct damos_sysfs_probe {
+	struct kobject kobj;
+};
+
+static struct damos_sysfs_probe *damos_sysfs_probe_alloc(void)
+{
+	return kzalloc_obj(struct damos_sysfs_probe);
+}
+
+static void damos_sysfs_probe_release(struct kobject *kobj)
+{
+	struct damos_sysfs_probe *probe = container_of(kobj,
+			struct damos_sysfs_probe, kobj);
+
+	kfree(probe);
+}
+
+static const struct kobj_type damos_sysfs_probe_ktype = {
+	.release = damos_sysfs_probe_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
 /*
  * probes directory
  */
 
 struct damos_sysfs_probes {
 	struct kobject kobj;
+	struct damos_sysfs_probe **probes_arr;
+	int nr;
 };
 
 static struct damos_sysfs_probes *damos_sysfs_probes_alloc(void)
@@ -23,6 +51,60 @@ static struct damos_sysfs_probes *damos_sysfs_probes_alloc(void)
 	return kzalloc_obj(struct damos_sysfs_probes);
 }
 
+static void damos_sysfs_probes_rm_dirs(struct damos_sysfs_probes *probes)
+{
+	struct damos_sysfs_probe **probes_arr = probes->probes_arr;
+	int i;
+
+	for (i = 0; i < probes->nr; i++)
+		kobject_put(&probes_arr[i]->kobj);
+	probes->nr = 0;
+	kfree(probes_arr);
+	probes->probes_arr = NULL;
+}
+
+static int damos_sysfs_probes_add_dirs(struct damos_sysfs_probes *probes,
+		struct damon_ctx *ctx)
+{
+	struct damon_probe *probe;
+	struct damos_sysfs_probe **probes_arr;
+	int i = 0;
+
+	damon_for_each_probe(probe, ctx)
+		i++;
+
+	if (!i)
+		return 0;
+
+	probes_arr = kmalloc_objs(*probes_arr, i);
+	if (!probes_arr)
+		return -ENOMEM;
+	probes->probes_arr = probes_arr;
+
+	i = 0;
+	damon_for_each_probe(probe, ctx) {
+		struct damos_sysfs_probe *sys_probe;
+		int err;
+
+		sys_probe = damos_sysfs_probe_alloc();
+		if (!sys_probe) {
+			damos_sysfs_probes_rm_dirs(probes);
+			return -ENOMEM;
+		}
+		err = kobject_init_and_add(&sys_probe->kobj,
+				&damos_sysfs_probe_ktype, &probes->kobj, "%d",
+				i);
+		if (err) {
+			kobject_put(&sys_probe->kobj);
+			damos_sysfs_probes_rm_dirs(probes);
+			return err;
+		}
+		probes_arr[i++] = sys_probe;
+		probes->nr++;
+	}
+	return 0;
+}
+
 static void damos_sysfs_probes_release(struct kobject *kobj)
 {
 	struct damos_sysfs_probes *probes = container_of(kobj,
@@ -67,7 +149,8 @@ static struct damon_sysfs_scheme_region *damon_sysfs_scheme_region_alloc(
 }
 
 static int damos_sysfs_region_add_dirs(
-		struct damon_sysfs_scheme_region *region)
+		struct damon_sysfs_scheme_region *region,
+		struct damon_ctx *ctx)
 {
 	struct damos_sysfs_probes *probes = damos_sysfs_probes_alloc();
 	int err;
@@ -76,18 +159,24 @@ static int damos_sysfs_region_add_dirs(
 		return -ENOMEM;
 	err = kobject_init_and_add(&probes->kobj, &damos_sysfs_probes_ktype,
 			&region->kobj, "probes");
-	if (err) {
-		kobject_put(&probes->kobj);
-		return err;
-	}
+	if (err)
+		goto fail;
+	err = damos_sysfs_probes_add_dirs(probes, ctx);
+	if (err)
+		goto fail;
 
 	region->probes = probes;
 	return 0;
+
+fail:
+	kobject_put(&probes->kobj);
+	return err;
 }
 
 static void damos_sysfs_region_rm_dirs(
 		struct damon_sysfs_scheme_region *region)
 {
+	damos_sysfs_probes_rm_dirs(region->probes);
 	kobject_put(&region->probes->kobj);
 }
 
@@ -3054,7 +3143,7 @@ void damos_sysfs_populate_region_dir(struct damon_sysfs_schemes *sysfs_schemes,
 				&sysfs_regions->kobj, "%d",
 				sysfs_regions->nr_regions))
 		goto out;
-	if (damos_sysfs_region_add_dirs(region))
+	if (damos_sysfs_region_add_dirs(region, ctx))
 		goto out;
 	return;
 
-- 
2.47.3