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-rw-r--r--init/Kconfig34
-rw-r--r--kernel/Kconfig.preempt15
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