+
+choice
+ prompt "RCU implementation type:"
+ default CLASSIC_RCU
+ help
+ This allows you to choose either the classic RCU implementation
+ that is designed for best read-side performance on non-realtime
+ systems, or the preemptible RCU implementation for best latency
+ on realtime systems. Note that some kernel preemption modes
+ will restrict your choice.
+
+ Select the default if you are unsure.
+
+config CLASSIC_RCU
+ bool "Classic RCU"
+ help
+ This option selects the classic RCU implementation that is
+ designed for best read-side performance on non-realtime
+ systems.
+
+ Say Y if you are unsure.
+
+config PREEMPT_RCU
+ bool "Preemptible RCU"
+ depends on PREEMPT
+ help
+ This option reduces the latency of the kernel by making certain
+ RCU sections preemptible. Normally RCU code is non-preemptible, if
+ this option is selected then read-only RCU sections become
+ preemptible. This helps latency, but may expose bugs due to
+ now-naive assumptions about each RCU read-side critical section
+ remaining on a given CPU through its execution.
+
+ Say N if you are unsure.
+
+endchoice