2 files changed, 18 insertions, 31 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 074ac97f55e3..a97924bc5b8d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -865,38 +865,10 @@ source "block/Kconfig"
 config PREEMPT_NOTIFIERS
         bool
 
-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"
+        def_bool !PREEMPT_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
+          systems.  Classic RCU is the default.  Note that the
+          PREEMPT_RCU symbol is used to select/deselect this option.
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 0669b70fa6a3..9fdba03dc1fc 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -52,8 +52,23 @@ config PREEMPT
 
 endchoice
 
+config PREEMPT_RCU
+        bool "Preemptible RCU"
+        depends on PREEMPT
+        default n
+        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.
+
 config RCU_TRACE
         bool "Enable tracing for RCU - currently stats in debugfs"
+        depends on PREEMPT_RCU
         select DEBUG_FS
         default y
         help