[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 b4cd11e58451..961ab20032f5 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 cb27068bfcd4..5f40b438b584 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 92f5a5266023..a853d87ff7e3 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 000000000000..587328be8216
--- /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.
+