Introduce a new DAMON sysfs interface file for exposing the newly added
DAMOS stat, nr_snapshots.  The file has the name same to the stat name
(nr_snapshots) and placed under the damos stat sysfs directory.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 30d20f5b3192..4d25469f957f 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -204,6 +204,7 @@ struct damon_sysfs_stats {
 	unsigned long sz_applied;
 	unsigned long sz_ops_filter_passed;
 	unsigned long qt_exceeds;
+	unsigned long nr_snapshots;
 };
 
 static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
@@ -265,6 +266,15 @@ static ssize_t qt_exceeds_show(struct kobject *kobj,
 	return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
 }
 
+static ssize_t nr_snapshots_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->nr_snapshots);
+}
+
 static void damon_sysfs_stats_release(struct kobject *kobj)
 {
 	kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
@@ -288,6 +298,9 @@ static struct kobj_attribute damon_sysfs_stats_sz_ops_filter_passed_attr =
 static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
 		__ATTR_RO_MODE(qt_exceeds, 0400);
 
+static struct kobj_attribute damon_sysfs_stats_nr_snapshots_attr =
+		__ATTR_RO_MODE(nr_snapshots, 0400);
+
 static struct attribute *damon_sysfs_stats_attrs[] = {
 	&damon_sysfs_stats_nr_tried_attr.attr,
 	&damon_sysfs_stats_sz_tried_attr.attr,
@@ -295,6 +308,7 @@ static struct attribute *damon_sysfs_stats_attrs[] = {
 	&damon_sysfs_stats_sz_applied_attr.attr,
 	&damon_sysfs_stats_sz_ops_filter_passed_attr.attr,
 	&damon_sysfs_stats_qt_exceeds_attr.attr,
+	&damon_sysfs_stats_nr_snapshots_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_stats);
@@ -2761,6 +2775,7 @@ void damon_sysfs_schemes_update_stats(
 		sysfs_stats->sz_ops_filter_passed =
 			scheme->stat.sz_ops_filter_passed;
 		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
+		sysfs_stats->nr_snapshots = scheme->stat.nr_snapshots;
 	}
 }
 
-- 
2.47.3