[PATCH v4 3/6] mm/damon/sysfs-schemes: add files for setting damos_filter->folio_size

[Usama Arif <usamaarif642@gmail.com>]

Add min and max files for damon filters to let the userspace decide
the min/max folio size to operate on. This will be needed to decide
what folio sizes to give pa_stat for.

Signed-off-by: Usama Arif <usamaarif642@gmail.com>
---
 include/linux/damon.h    | 11 +++++++++
 mm/damon/core.c          |  3 +++
 mm/damon/sysfs-schemes.c | 53 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index af525252b853..6f30ceeff215 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -35,6 +35,16 @@ struct damon_addr_range {
 	unsigned long end;
 };
 
+/**
+ * struct damon_folio_size - Represents size of folio filter on [@min, @max].
+ * @min:	Min size of the folio (inclusive).
+ * @max:	Max size of the folio (inclusive).
+ */
+struct damon_folio_size {
+	unsigned long min;
+	unsigned long max;
+};
+
 /**
  * struct damon_region - Represents a monitoring target region.
  * @ar:			The address range of the region.
@@ -377,6 +387,7 @@ struct damos_filter {
 		struct damon_addr_range addr_range;
 		int target_idx;
 	};
+	struct damon_folio_size folio_size;
 	struct list_head list;
 };
 
diff --git a/mm/damon/core.c b/mm/damon/core.c
index c7b981308862..27323e3a800d 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -776,6 +776,9 @@ static void damos_commit_filter_arg(
 	case DAMOS_FILTER_TYPE_TARGET:
 		dst->target_idx = src->target_idx;
 		break;
+	case DAMOS_FILTER_TYPE_HUGEPAGE:
+		dst->folio_size = src->folio_size;
+		break;
 	default:
 		break;
 	}
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 98f93ae9f59e..bc7ca43ca9c4 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -316,6 +316,7 @@ struct damon_sysfs_scheme_filter {
 	bool allow;
 	char *memcg_path;
 	struct damon_addr_range addr_range;
+	struct damon_folio_size folio_size;
 	int target_idx;
 };
 
@@ -469,6 +470,43 @@ static ssize_t addr_end_store(struct kobject *kobj,
 	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
 			struct damon_sysfs_scheme_filter, kobj);
 	int err = kstrtoul(buf, 0, &filter->addr_range.end);
+	return err ? err : count;
+}
+
+static ssize_t min_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+
+	return sysfs_emit(buf, "%lu\n", filter->folio_size.min);
+}
+
+static ssize_t min_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+	int err = kstrtoul(buf, 0, &filter->folio_size.min);
+
+	return err ? err : count;
+}
+
+static ssize_t max_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+
+	return sysfs_emit(buf, "%lu\n", filter->folio_size.max);
+}
+
+static ssize_t max_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+			struct damon_sysfs_scheme_filter, kobj);
+	int err = kstrtoul(buf, 0, &filter->folio_size.max);
 
 	return err ? err : count;
 }
@@ -519,6 +557,12 @@ static struct kobj_attribute damon_sysfs_scheme_filter_addr_start_attr =
 static struct kobj_attribute damon_sysfs_scheme_filter_addr_end_attr =
 		__ATTR_RW_MODE(addr_end, 0600);
 
+static struct kobj_attribute damon_sysfs_scheme_filter_min_attr =
+		__ATTR_RW_MODE(min, 0600);
+
+static struct kobj_attribute damon_sysfs_scheme_filter_max_attr =
+		__ATTR_RW_MODE(max, 0600);
+
 static struct kobj_attribute damon_sysfs_scheme_filter_damon_target_idx_attr =
 		__ATTR_RW_MODE(damon_target_idx, 0600);
 
@@ -529,6 +573,8 @@ static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
 	&damon_sysfs_scheme_filter_memcg_path_attr.attr,
 	&damon_sysfs_scheme_filter_addr_start_attr.attr,
 	&damon_sysfs_scheme_filter_addr_end_attr.attr,
+	&damon_sysfs_scheme_filter_min_attr.attr,
+	&damon_sysfs_scheme_filter_max_attr.attr,
 	&damon_sysfs_scheme_filter_damon_target_idx_attr.attr,
 	NULL,
 };
@@ -1953,6 +1999,13 @@ static int damon_sysfs_add_scheme_filters(struct damos *scheme,
 			filter->addr_range = sysfs_filter->addr_range;
 		} else if (filter->type == DAMOS_FILTER_TYPE_TARGET) {
 			filter->target_idx = sysfs_filter->target_idx;
+		} else if (filter->type == DAMOS_FILTER_TYPE_HUGEPAGE) {
+			if (sysfs_filter->folio_size.min >
+					sysfs_filter->folio_size.max) {
+				damos_destroy_filter(filter);
+				return -EINVAL;
+			}
+			filter->folio_size = sysfs_filter->folio_size;
 		}
 
 		damos_add_filter(scheme, filter);
-- 
2.43.5