sched: Provide Kconfig support for default dynamic preempt mode

[sfrench/cifs-2.6.git] / kernel / Kconfig.preempt

diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 5876e30c5740d8ff52de11407fc283d7d2b4e838..60f1bfc3c7b246df3b6fc9d0381e6802471a59ed 100644 (file)
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -2,10 +2,11 @@
 
 choice
        prompt "Preemption Model"
-       default PREEMPT_NONE
+       default PREEMPT_NONE_BEHAVIOUR
 
-config PREEMPT_NONE
+config PREEMPT_NONE_BEHAVIOUR
        bool "No Forced Preemption (Server)"
+       select PREEMPT_NONE if !PREEMPT_DYNAMIC
        help
          This is the traditional Linux preemption model, geared towards
          throughput. It will still provide good latencies most of the
@@ -17,9 +18,10 @@ config PREEMPT_NONE
          raw processing power of the kernel, irrespective of scheduling
          latencies.
 
-config PREEMPT_VOLUNTARY
+config PREEMPT_VOLUNTARY_BEHAVIOUR
        bool "Voluntary Kernel Preemption (Desktop)"
        depends on !ARCH_NO_PREEMPT
+       select PREEMPT_VOLUNTARY if !PREEMPT_DYNAMIC
        help
          This option reduces the latency of the kernel by adding more
          "explicit preemption points" to the kernel code. These new
@@ -35,12 +37,10 @@ config PREEMPT_VOLUNTARY
 
          Select this if you are building a kernel for a desktop system.
 
-config PREEMPT
+config PREEMPT_BEHAVIOUR
        bool "Preemptible Kernel (Low-Latency Desktop)"
        depends on !ARCH_NO_PREEMPT
-       select PREEMPTION
-       select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
-       select PREEMPT_DYNAMIC if HAVE_PREEMPT_DYNAMIC
+       select PREEMPT
        help
          This option reduces the latency of the kernel by making
          all kernel code (that is not executing in a critical section)
@@ -58,7 +58,7 @@ config PREEMPT
 
 config PREEMPT_RT
        bool "Fully Preemptible Kernel (Real-Time)"
-       depends on EXPERT && ARCH_SUPPORTS_RT
+       depends on EXPERT && ARCH_SUPPORTS_RT && !PREEMPT_DYNAMIC
        select PREEMPTION
        help
          This option turns the kernel into a real-time kernel by replacing
@@ -75,6 +75,17 @@ config PREEMPT_RT
 
 endchoice
 
+config PREEMPT_NONE
+       bool
+
+config PREEMPT_VOLUNTARY
+       bool
+
+config PREEMPT
+       bool
+       select PREEMPTION
+       select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
+
 config PREEMPT_COUNT
        bool
 
@@ -83,7 +94,10 @@ config PREEMPTION
        select PREEMPT_COUNT
 
 config PREEMPT_DYNAMIC
-       bool
+       bool "Preemption behaviour defined on boot"
+       depends on HAVE_PREEMPT_DYNAMIC
+       select PREEMPT
+       default y
        help
          This option allows to define the preemption model on the kernel
          command line parameter and thus override the default preemption