[PATCH] consolidate PREEMPT options into kernel/Kconfig.preempt

This patch consolidates the CONFIG_PREEMPT and CONFIG_PREEMPT_BKL
preemption options into kernel/Kconfig.preempt.  This, besides reducing
source-code, also enables more centralized tweaking of preemption related
options.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 28 insertions, 69 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index b4cd11e..961ab20 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -510,28 +510,7 @@ config SCHED_SMT
 	  cost of slightly increased overhead in some places. If unsure say
 	  N here.
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	help
-	  This option reduces the latency of the kernel when reacting to
-	  real-time or interactive events by allowing a low priority process to
-	  be preempted even if it is in kernel mode executing a system call.
-	  This allows applications to run more reliably even when the system is
-	  under load.
-
-	  Say Y here if you are building a kernel for a desktop, embedded
-	  or real-time system.  Say N if you are unsure.
-
-config PREEMPT_BKL
-	bool "Preempt The Big Kernel Lock"
-	depends on PREEMPT
-	default y
-	help
-	  This option reduces the latency of the kernel by making the
-	  big kernel lock preemptible.
-
-	  Say Y here if you are building a kernel for a desktop system.
-	  Say N if you are unsure.
+source "kernel/Kconfig.preempt"
 
 config X86_UP_APIC
 	bool "Local APIC support on uniprocessors"
diff --git a/arch/ppc64/Kconfig b/arch/ppc64/Kconfig
index cb27068..5f40b43 100644
--- a/arch/ppc64/Kconfig
+++ b/arch/ppc64/Kconfig
@@ -270,26 +270,7 @@ config SCHED_SMT
 	  when dealing with POWER5 cpus at a cost of slightly increased
 	  overhead in some places. If unsure say N here.
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	help
-	  This option reduces the latency of the kernel when reacting to
-	  real-time or interactive events by allowing a low priority process to
-	  be preempted even if it is in kernel mode executing a system call.
-
-	  Say Y here if you are building a kernel for a desktop, embedded
-	  or real-time system.  Say N if you are unsure.
-
-config PREEMPT_BKL
-	bool "Preempt The Big Kernel Lock"
-	depends on PREEMPT
-	default y
-	help
-	  This option reduces the latency of the kernel by making the
-	  big kernel lock preemptible.
-
-	  Say Y here if you are building a kernel for a desktop system.
-	  Say N if you are unsure.
+source "kernel/Kconfig.preempt"
 
 config EEH
 	bool "PCI Extended Error Handling (EEH)" if EMBEDDED
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 92f5a52..a853d87 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -207,33 +207,6 @@ config SMP
 
 	  If you don't know what to do here, say N.
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	---help---
-	  This option reduces the latency of the kernel when reacting to
-	  real-time or interactive events by allowing a low priority process to
-	  be preempted even if it is in kernel mode executing a system call.
-	  This allows applications to run more reliably even when the system is
-	  under load. On contrary it may also break your drivers and add
-	  priority inheritance problems to your system. Don't select it if
-	  you rely on a stable system or have slightly obscure hardware.
-	  It's also not very well tested on x86-64 currently.
-	  You have been warned.
-
-	  Say Y here if you are feeling brave and building a kernel for a
-	  desktop, embedded or real-time system.  Say N if you are unsure.
-
-config PREEMPT_BKL
-	bool "Preempt The Big Kernel Lock"
-	depends on PREEMPT
-	default y
-	help
-	  This option reduces the latency of the kernel by making the
-	  big kernel lock preemptible.
-
-	  Say Y here if you are building a kernel for a desktop system.
-	  Say N if you are unsure.
-
 config SCHED_SMT
 	bool "SMT (Hyperthreading) scheduler support"
 	depends on SMP
@@ -244,6 +217,8 @@ config SCHED_SMT
 	  cost of slightly increased overhead in some places. If unsure say
 	  N here.
 
+source "kernel/Kconfig.preempt"
+
 config K8_NUMA
        bool "K8 NUMA support"
        select NUMA
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
new file mode 100644
index 0000000..587328b
--- /dev/null
+++ b/kernel/Kconfig.preempt
@@ -0,0 +1,24 @@
+
+config PREEMPT
+	bool "Preemptible Kernel"
+	help
+	  This option reduces the latency of the kernel when reacting to
+	  real-time or interactive events by allowing a low priority process to
+	  be preempted even if it is in kernel mode executing a system call.
+	  This allows applications to run more reliably even when the system is
+	  under load.
+
+	  Say Y here if you are building a kernel for a desktop, embedded
+	  or real-time system.  Say N if you are unsure.
+
+config PREEMPT_BKL
+	bool "Preempt The Big Kernel Lock"
+	depends on PREEMPT
+	default y
+	help
+	  This option reduces the latency of the kernel by making the
+	  big kernel lock preemptible.
+
+	  Say Y here if you are building a kernel for a desktop system.
+	  Say N if you are unsure.
+