+/*
+ * Limiting the nesting level to 256 to keep instructions small in the read
+ * fast-path.
+ */
+#define RCU_GP_COUNT (1U << 0)
+#define RCU_GP_CTR_BIT (1U << 8)
+#define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_BIT - 1)
+
+/* Global quiescent period counter with low-order bits unused. */
+extern int urcu_gp_ctr;