Implement sysfs file for showing the per-region per-probe hits count.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 41 +++++++++++++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 7 deletions(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 91d6ddcf1b32d..43a8224d991e8 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -16,11 +16,27 @@
 
 struct damos_sysfs_probe {
 	struct kobject kobj;
+	unsigned char hits;
 };
 
-static struct damos_sysfs_probe *damos_sysfs_probe_alloc(void)
+static struct damos_sysfs_probe *damos_sysfs_probe_alloc(unsigned char hits)
 {
-	return kzalloc_obj(struct damos_sysfs_probe);
+	struct damos_sysfs_probe *probe;
+
+	probe = kzalloc_obj(*probe);
+	if (!probe)
+		return NULL;
+	probe->hits = hits;
+	return probe;
+}
+
+static ssize_t hits_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damos_sysfs_probe *probe = container_of(kobj,
+			struct damos_sysfs_probe, kobj);
+
+	return sysfs_emit(buf, "%hhu\n", probe->hits);
 }
 
 static void damos_sysfs_probe_release(struct kobject *kobj)
@@ -31,9 +47,19 @@ static void damos_sysfs_probe_release(struct kobject *kobj)
 	kfree(probe);
 }
 
+static struct kobj_attribute damos_sysfs_probe_hits_attr =
+		__ATTR_RO_MODE(hits, 0400);
+
+static struct attribute *damos_sysfs_probe_attrs[] = {
+	&damos_sysfs_probe_hits_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damos_sysfs_probe);
+
 static const struct kobj_type damos_sysfs_probe_ktype = {
 	.release = damos_sysfs_probe_release,
 	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damos_sysfs_probe_groups,
 };
 
 /*
@@ -64,7 +90,7 @@ static void damos_sysfs_probes_rm_dirs(struct damos_sysfs_probes *probes)
 }
 
 static int damos_sysfs_probes_add_dirs(struct damos_sysfs_probes *probes,
-		struct damon_ctx *ctx)
+		struct damon_ctx *ctx, struct damon_region *region)
 {
 	struct damon_probe *probe;
 	struct damos_sysfs_probe **probes_arr;
@@ -86,7 +112,7 @@ static int damos_sysfs_probes_add_dirs(struct damos_sysfs_probes *probes,
 		struct damos_sysfs_probe *sys_probe;
 		int err;
 
-		sys_probe = damos_sysfs_probe_alloc();
+		sys_probe = damos_sysfs_probe_alloc(region->probe_hits[i]);
 		if (!sys_probe) {
 			damos_sysfs_probes_rm_dirs(probes);
 			return -ENOMEM;
@@ -150,7 +176,8 @@ 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_ctx *ctx)
+		struct damon_ctx *ctx,
+		struct damon_region *dregion)
 {
 	struct damos_sysfs_probes *probes = damos_sysfs_probes_alloc();
 	int err;
@@ -161,7 +188,7 @@ static int damos_sysfs_region_add_dirs(
 			&region->kobj, "probes");
 	if (err)
 		goto fail;
-	err = damos_sysfs_probes_add_dirs(probes, ctx);
+	err = damos_sysfs_probes_add_dirs(probes, ctx, dregion);
 	if (err)
 		goto fail;
 
@@ -3143,7 +3170,7 @@ 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, ctx))
+	if (damos_sysfs_region_add_dirs(region, ctx, r))
 		goto out;
 	return;
 
-- 
2.47.3