diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index d4b2f1c7..243e287 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -103,6 +103,12 @@
 		{ .first = &init_task.pids[PIDTYPE_SID].node },		\
 	},								\
 	.rcu		= RCU_HEAD_INIT,				\
+	.level		= 0,						\
+	.numbers	= { {						\
+		.nr		= 0,					\
+		.ns		= &init_pid_ns,				\
+		.pid_chain	= { .next = NULL, .pprev = NULL },	\
+	}, }								\
 }
 
 #define INIT_PID_LINK(type) 					\
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 1e0e4e3..e5865a9 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -40,6 +40,20 @@
  * processes.
  */
 
+
+/*
+ * struct upid is used to get the id of the struct pid, as it is
+ * seen in particular namespace. Later the struct pid is found with
+ * find_pid_ns() using the int nr and struct pid_namespace *ns.
+ */
+
+struct upid {
+	/* Try to keep pid_chain in the same cacheline as nr for find_pid */
+	int nr;
+	struct pid_namespace *ns;
+	struct hlist_node pid_chain;
+};
+
 struct pid
 {
 	atomic_t count;
@@ -49,6 +63,8 @@
 	/* lists of tasks that use this pid */
 	struct hlist_head tasks[PIDTYPE_MAX];
 	struct rcu_head rcu;
+	int level;
+	struct upid numbers[1];
 };
 
 extern struct pid init_struct_pid;