[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>

[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>
Ingo Molnar · Linus Torvalds
1 parent 7f1867a5b3
Showing 4 changed files with 28 additions and 69 deletions Side-by-side Diff
arch/i386/Kconfig
arch/ppc64/Kconfig
arch/x86_64/Kconfig
kernel/Kconfig.preempt
@@ -510,28 +510,7 @@
 	  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"
@@ -270,26 +270,7 @@
 	  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
@@ -207,33 +207,6 @@
  
 	  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
@@ -243,6 +216,8 @@
 	  when dealing with Intel Pentium 4 chips with HyperThreading at a
 	  cost of slightly increased overhead in some places. If unsure say
 	  N here.
+
+source "kernel/Kconfig.preempt"
  
 config K8_NUMA
        bool "K8 NUMA support"
+
+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.
...	...	@@ -510,28 +510,7 @@
510	510	cost of slightly increased overhead in some places. If unsure say
511	511	N here.
512	512
513		-config PREEMPT
514		- bool "Preemptible Kernel"
515		- help
516		- This option reduces the latency of the kernel when reacting to
517		- real-time or interactive events by allowing a low priority process to
518		- be preempted even if it is in kernel mode executing a system call.
519		- This allows applications to run more reliably even when the system is
520		- under load.
521		-
522		- Say Y here if you are building a kernel for a desktop, embedded
523		- or real-time system. Say N if you are unsure.
524		-
525		-config PREEMPT_BKL
526		- bool "Preempt The Big Kernel Lock"
527		- depends on PREEMPT
528		- default y
529		- help
530		- This option reduces the latency of the kernel by making the
531		- big kernel lock preemptible.
532		-
533		- Say Y here if you are building a kernel for a desktop system.
534		- Say N if you are unsure.
	513	+source "kernel/Kconfig.preempt"
535	514
536	515	config X86_UP_APIC
537	516	bool "Local APIC support on uniprocessors"
...	...	@@ -270,26 +270,7 @@
270	270	when dealing with POWER5 cpus at a cost of slightly increased
271	271	overhead in some places. If unsure say N here.
272	272
273		-config PREEMPT
274		- bool "Preemptible Kernel"
275		- help
276		- This option reduces the latency of the kernel when reacting to
277		- real-time or interactive events by allowing a low priority process to
278		- be preempted even if it is in kernel mode executing a system call.
279		-
280		- Say Y here if you are building a kernel for a desktop, embedded
281		- or real-time system. Say N if you are unsure.
282		-
283		-config PREEMPT_BKL
284		- bool "Preempt The Big Kernel Lock"
285		- depends on PREEMPT
286		- default y
287		- help
288		- This option reduces the latency of the kernel by making the
289		- big kernel lock preemptible.
290		-
291		- Say Y here if you are building a kernel for a desktop system.
292		- Say N if you are unsure.
	273	+source "kernel/Kconfig.preempt"
293	274
294	275	config EEH
295	276	bool "PCI Extended Error Handling (EEH)" if EMBEDDED
...	...	@@ -207,33 +207,6 @@
207	207
208	208	If you don't know what to do here, say N.
209	209
210		-config PREEMPT
211		- bool "Preemptible Kernel"
212		- ---help---
213		- This option reduces the latency of the kernel when reacting to
214		- real-time or interactive events by allowing a low priority process to
215		- be preempted even if it is in kernel mode executing a system call.
216		- This allows applications to run more reliably even when the system is
217		- under load. On contrary it may also break your drivers and add
218		- priority inheritance problems to your system. Don't select it if
219		- you rely on a stable system or have slightly obscure hardware.
220		- It's also not very well tested on x86-64 currently.
221		- You have been warned.
222		-
223		- Say Y here if you are feeling brave and building a kernel for a
224		- desktop, embedded or real-time system. Say N if you are unsure.
225		-
226		-config PREEMPT_BKL
227		- bool "Preempt The Big Kernel Lock"
228		- depends on PREEMPT
229		- default y
230		- help
231		- This option reduces the latency of the kernel by making the
232		- big kernel lock preemptible.
233		-
234		- Say Y here if you are building a kernel for a desktop system.
235		- Say N if you are unsure.
236		-
237	210	config SCHED_SMT
238	211	bool "SMT (Hyperthreading) scheduler support"
239	212	depends on SMP
...	...	@@ -243,6 +216,8 @@
243	216	when dealing with Intel Pentium 4 chips with HyperThreading at a
244	217	cost of slightly increased overhead in some places. If unsure say
245	218	N here.
	219	+
	220	+source "kernel/Kconfig.preempt"
246	221
247	222	config K8_NUMA
248	223	bool "K8 NUMA support"
	1	+
	2	+config PREEMPT
	3	+ bool "Preemptible Kernel"
	4	+ help
	5	+ This option reduces the latency of the kernel when reacting to
	6	+ real-time or interactive events by allowing a low priority process to
	7	+ be preempted even if it is in kernel mode executing a system call.
	8	+ This allows applications to run more reliably even when the system is
	9	+ under load.
	10	+
	11	+ Say Y here if you are building a kernel for a desktop, embedded
	12	+ or real-time system. Say N if you are unsure.
	13	+
	14	+config PREEMPT_BKL
	15	+ bool "Preempt The Big Kernel Lock"
	16	+ depends on PREEMPT
	17	+ default y
	18	+ help
	19	+ This option reduces the latency of the kernel by making the
	20	+ big kernel lock preemptible.
	21	+
	22	+ Say Y here if you are building a kernel for a desktop system.
	23	+ Say N if you are unsure.