[RFC PATCH 2/2] mm/damon/sysfs: introduce priority sysfs interface

[Enze Li <lienze@kylinos.cn>]

This patch extends the DAMON sysfs interface to support the
configuration of target priorities, enabling users to assign and adjust
the relative importance of monitored processes at runtime.

Signed-off-by: Enze Li <lienze@kylinos.cn>
---
 mm/damon/sysfs.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index e2bd2d7becdd..224d9e89d967 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -213,6 +213,9 @@ struct damon_sysfs_target {
 	struct damon_sysfs_regions *regions;
 	int pid;
 	bool obsolete;
+#ifdef CONFIG_DAMON_AUTO_TUNING
+	int priority;
+#endif
 };
 
 static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
@@ -298,9 +301,44 @@ static struct kobj_attribute damon_sysfs_target_pid_attr =
 static struct kobj_attribute damon_sysfs_target_obsolete_attr =
 		__ATTR_RW_MODE(obsolete_target, 0600);
 
+#ifdef CONFIG_DAMON_AUTO_TUNING
+static ssize_t target_priority_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_target *target = container_of(kobj,
+			struct damon_sysfs_target, kobj);
+
+	return sysfs_emit(buf, "%d\n", target->priority);
+}
+
+static ssize_t target_priority_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int err, value;
+	struct damon_sysfs_target *target = container_of(kobj,
+			struct damon_sysfs_target, kobj);
+	err = kstrtoint(buf, 0, &value);
+	if (err)
+		return -EINVAL;
+
+	if (value > 0 && value <= 100)
+		target->priority = value;
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static struct kobj_attribute damon_sysfs_target_priority =
+		__ATTR_RW_MODE(target_priority, 0600);
+#endif
+
 static struct attribute *damon_sysfs_target_attrs[] = {
 	&damon_sysfs_target_pid_attr.attr,
 	&damon_sysfs_target_obsolete_attr.attr,
+#ifdef CONFIG_DAMON_AUTO_TUNING
+	&damon_sysfs_target_priority.attr,
+#endif
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_target);
@@ -1406,6 +1444,9 @@ static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
 			return -EINVAL;
 	}
 	t->obsolete = sys_target->obsolete;
+#ifdef CONFIG_DAMON_AUTO_TUNING
+	t->priority = sys_target->priority;
+#endif
 	return damon_sysfs_set_regions(t, sys_target->regions, ctx->min_sz_region);
 }
 
-- 
2.43.0