struct cgroup {
unsigned long flags; /* "unsigned long" so bitops work */
- int id; /* idr allocated in-hierarchy ID */
+ /*
+ * idr allocated in-hierarchy ID.
+ *
+ * The ID of the root cgroup is always 0, and a new cgroup
+ * will be assigned with a smallest available ID.
+ */
+ int id;
/*
* We link our 'sibling' struct into our parent's 'children'.