[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>

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index b4cd11e584517ac496859996393853d9d14e4ad8..961ab20032f5b18a51a14b5ad34922760cf83cb3 100644 (file)
--- 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 cb27068bfcd49694123c1cf9cc27c692a80c2c9d..5f40b438b584fa8e92f9ab999d1ac38583f0d0c8 100644 (file)
--- 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 92f5a526602394be5154e712254b8a1afa200781..a853d87ff7e33000efef7f361f44a70021d4a4a6 100644 (file)
--- 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 (file)
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.
+