[RFC PATCH v2 06/11] mm/damon/sysfs-schemes: implement filter directory

SeongJae Park
2022-11-30T20:10:06Z

Implement DAMOS filter directory which will be located under the filters
directory. The directory provides three files, namely type, matching,
and memcg_path. 'type' and 'matching' will be directly connected to the
fields of 'struct damos_filter' having same name. 'memcg_path' will
receive the path of the memory cgroup of the interest and later
converted to memcg id when it's committed.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/sysfs-schemes.c | 128 +++++++++++++++++++++++++++++++++++++++
1 file changed, 128 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 50c8148cb474..afbfc55a8e84 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -258,6 +258,134 @@ static struct kobj_type damon_sysfs_stats_ktype = {
.default_groups = damon_sysfs_stats_groups,
};

+/*
+ * filter directory
+ */
+
+struct damon_sysfs_scheme_filter {
+ struct kobject kobj;
+ enum damos_filter_type type;
+ bool matching;
+ char *memcg_path;
+};
+
+/* Should match with enum damos_filter_type */
+static const char * const damon_sysfs_scheme_filter_type_strs[] = {
+ "anon",
+ "memcg",
+};
+
+static ssize_t type_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, "%s\n",
+ damon_sysfs_scheme_filter_type_strs[filter->type]);
+}
+
+static ssize_t type_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);
+ enum damos_filter_type type;
+ ssize_t ret = -EINVAL;
+
+ for (type = 0; type < NR_DAMOS_FILTER_TYPES; type++) {
+ if (sysfs_streq(buf, damon_sysfs_scheme_filter_type_strs[
+ type])) {
+ filter->type = type;
+ ret = count;
+ break;
+ }
+ }
+ return ret;
+}
+
+static ssize_t matching_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, "%c\n", filter->matching ? 'Y' : 'N');
+}
+
+static ssize_t matching_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);
+ bool matching;
+ int err = kstrtobool(buf, &matching);
+
+ if (err)
+ return err;
+
+ filter->matching = matching;
+ return count;
+}
+
+static ssize_t memcg_path_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, "%s\n",
+ filter->memcg_path ? filter->memcg_path : "");
+}
+
+static ssize_t memcg_path_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);
+ char *path = kmalloc(sizeof(*path) * (count + 1), GFP_KERNEL);
+
+ if (!path)
+ return -ENOMEM;
+
+ strncpy(path, buf, count);
+ path[count] = '\0';
+ filter->memcg_path = path;
+ return count;
+}
+
+static void damon_sysfs_scheme_filter_release(struct kobject *kobj)
+{
+ struct damon_sysfs_scheme_filter *filter = container_of(kobj,
+ struct damon_sysfs_scheme_filter, kobj);
+
+ kfree(filter->memcg_path);
+ kfree(filter);
+}
+
+static struct kobj_attribute damon_sysfs_scheme_filter_type_attr =
+ __ATTR_RW_MODE(type, 0600);
+
+static struct kobj_attribute damon_sysfs_scheme_filter_matching_attr =
+ __ATTR_RW_MODE(matching, 0600);
+
+static struct kobj_attribute damon_sysfs_scheme_filter_memcg_path_attr =
+ __ATTR_RW_MODE(memcg_path, 0600);
+
+static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
+ &damon_sysfs_scheme_filter_type_attr.attr,
+ &damon_sysfs_scheme_filter_matching_attr.attr,
+ &damon_sysfs_scheme_filter_memcg_path_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_scheme_filter);
+
+static struct kobj_type damon_sysfs_scheme_filter_ktype = {
+ .release = damon_sysfs_scheme_filter_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_scheme_filter_groups,
+};
+
/*
* filters directory
*/
--
2.25.1