blob: 48efefcac12a97ade63f6808c2e24570f4d37ba3 [file] [log] [blame]
Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670ea2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
22 default y
23
Al Boldiff0cfc62007-07-31 00:39:23 -070024menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26config EXPERIMENTAL
27 bool "Prompt for development and/or incomplete code/drivers"
28 ---help---
29 Some of the various things that Linux supports (such as network
30 drivers, file systems, network protocols, etc.) can be in a state
31 of development where the functionality, stability, or the level of
32 testing is not yet high enough for general use. This is usually
33 known as the "alpha-test" phase among developers. If a feature is
34 currently in alpha-test, then the developers usually discourage
35 uninformed widespread use of this feature by the general public to
36 avoid "Why doesn't this work?" type mail messages. However, active
37 testing and use of these systems is welcomed. Just be aware that it
38 may not meet the normal level of reliability or it may fail to work
39 in some special cases. Detailed bug reports from people familiar
40 with the kernel internals are usually welcomed by the developers
41 (before submitting bug reports, please read the documents
42 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
43 <file:Documentation/BUG-HUNTING>, and
44 <file:Documentation/oops-tracing.txt> in the kernel source).
45
46 This option will also make obsoleted drivers available. These are
47 drivers that have been replaced by something else, and/or are
48 scheduled to be removed in a future kernel release.
49
50 Unless you intend to help test and develop a feature or driver that
51 falls into this category, or you have a situation that requires
52 using these features, you should probably say N here, which will
53 cause the configurator to present you with fewer choices. If
54 you say Y here, you will be offered the choice of using features or
55 drivers that are currently considered to be in the alpha-test phase.
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057config BROKEN
58 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60config BROKEN_ON_SMP
61 bool
62 depends on BROKEN || !SMP
63 default y
64
65config LOCK_KERNEL
66 bool
67 depends on SMP || PREEMPT
68 default y
69
70config INIT_ENV_ARG_LIMIT
71 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070072 default 32 if !UML
73 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080075 Maximum of each of the number of arguments and environment
76 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Roland McGrath84336462009-12-21 16:24:06 -080079config CROSS_COMPILE
80 string "Cross-compiler tool prefix"
81 help
82 Same as running 'make CROSS_COMPILE=prefix-' but stored for
83 default make runs in this kernel build directory. You don't
84 need to set this unless you want the configured kernel build
85 directory to select the cross-compiler automatically.
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087config LOCALVERSION
88 string "Local version - append to kernel release"
89 help
90 Append an extra string to the end of your kernel version.
91 This will show up when you type uname, for example.
92 The string you set here will be appended after the contents of
93 any files with a filename matching localversion* in your
94 object and source tree, in that order. Your total string can
95 be a maximum of 64 characters.
96
Ryan Andersonaaebf432005-07-31 04:57:49 -040097config LOCALVERSION_AUTO
98 bool "Automatically append version information to the version string"
99 default y
100 help
101 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200102 release tree by looking for git tags that belong to the current
103 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400104
105 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400107 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200108 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400109
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 (The actual string used here is the first eight characters produced
111 by running the command:
112
113 $ git rev-parse --verify HEAD
114
115 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400116
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800117config HAVE_KERNEL_GZIP
118 bool
119
120config HAVE_KERNEL_BZIP2
121 bool
122
123config HAVE_KERNEL_LZMA
124 bool
125
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800126config HAVE_KERNEL_LZO
127 bool
128
Alain Knaff30d65db2009-01-04 22:46:17 +0100129choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800130 prompt "Kernel compression mode"
131 default KERNEL_GZIP
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800132 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800133 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100134 The linux kernel is a kind of self-extracting executable.
135 Several compression algorithms are available, which differ
136 in efficiency, compression and decompression speed.
137 Compression speed is only relevant when building a kernel.
138 Decompression speed is relevant at each boot.
139
140 If you have any problems with bzip2 or lzma compressed
141 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
142 version of this functionality (bzip2 only), for 2.4, was
143 supplied by Christian Ludwig)
144
145 High compression options are mostly useful for users, who
146 are low on disk space (embedded systems), but for whom ram
147 size matters less.
148
149 If in doubt, select 'gzip'
150
151config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800152 bool "Gzip"
153 depends on HAVE_KERNEL_GZIP
154 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800155 The old and tried gzip compression. It provides a good balance
156 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100157
158config KERNEL_BZIP2
159 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800160 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100161 help
162 Its compression ratio and speed is intermediate.
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800163 Decompression speed is slowest among the three. The kernel
164 size is about 10% smaller with bzip2, in comparison to gzip.
165 Bzip2 uses a large amount of memory. For modern kernels you
166 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100167
168config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800169 bool "LZMA"
170 depends on HAVE_KERNEL_LZMA
171 help
172 The most recent compression algorithm.
173 Its ratio is best, decompression speed is between the other
174 two. Compression is slowest. The kernel size is about 33%
175 smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100176
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800177config KERNEL_LZO
178 bool "LZO"
179 depends on HAVE_KERNEL_LZO
180 help
181 Its compression ratio is the poorest among the 4. The kernel
182 size is about about 10% bigger than gzip; however its speed
183 (both compression and decompression) is the fastest.
184
Alain Knaff30d65db2009-01-04 22:46:17 +0100185endchoice
186
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187config SWAP
188 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200189 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 default y
191 help
192 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100193 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 used to provide more virtual memory than the actual RAM present
195 in your computer. If unsure say Y.
196
197config SYSVIPC
198 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 ---help---
200 Inter Process Communication is a suite of library functions and
201 system calls which let processes (running programs) synchronize and
202 exchange information. It is generally considered to be a good thing,
203 and some programs won't run unless you say Y here. In particular, if
204 you want to run the DOS emulator dosemu under Linux (read the
205 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
206 you'll need to say Y here.
207
208 You can find documentation about IPC with "info ipc" and also in
209 section 6.4 of the Linux Programmer's Guide, available from
210 <http://www.tldp.org/guides.html>.
211
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800212config SYSVIPC_SYSCTL
213 bool
214 depends on SYSVIPC
215 depends on SYSCTL
216 default y
217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218config POSIX_MQUEUE
219 bool "POSIX Message Queues"
220 depends on NET && EXPERIMENTAL
221 ---help---
222 POSIX variant of message queues is a part of IPC. In POSIX message
223 queues every message has a priority which decides about succession
224 of receiving it by a process. If you want to compile and run
225 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200226 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228 POSIX message queues are visible as a filesystem called 'mqueue'
229 and can be mounted somewhere if you want to do filesystem
230 operations on message queues.
231
232 If unsure, say Y.
233
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700234config POSIX_MQUEUE_SYSCTL
235 bool
236 depends on POSIX_MQUEUE
237 depends on SYSCTL
238 default y
239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240config BSD_PROCESS_ACCT
241 bool "BSD Process Accounting"
242 help
243 If you say Y here, a user level program will be able to instruct the
244 kernel (via a special system call) to write process accounting
245 information to a file: whenever a process exits, information about
246 that process will be appended to the file by the kernel. The
247 information includes things such as creation time, owning user,
248 command name, memory usage, controlling terminal etc. (the complete
249 list is in the struct acct in <file:include/linux/acct.h>). It is
250 up to the user level program to do useful things with this
251 information. This is generally a good idea, so say Y.
252
253config BSD_PROCESS_ACCT_V3
254 bool "BSD Process Accounting version 3 file format"
255 depends on BSD_PROCESS_ACCT
256 default n
257 help
258 If you say Y here, the process accounting information is written
259 in a new file format that also logs the process IDs of each
260 process and it's parent. Note that this file format is incompatible
261 with previous v0/v1/v2 file formats, so you will need updated tools
262 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300263 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Shailabh Nagarc7572492006-07-14 00:24:40 -0700265config TASKSTATS
266 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
267 depends on NET
268 default n
269 help
270 Export selected statistics for tasks/processes through the
271 generic netlink interface. Unlike BSD process accounting, the
272 statistics are available during the lifetime of tasks/processes as
273 responses to commands. Like BSD accounting, they are sent to user
274 space on task exit.
275
276 Say N if unsure.
277
Shailabh Nagarca74e922006-07-14 00:24:36 -0700278config TASK_DELAY_ACCT
279 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700280 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700281 help
282 Collect information on time spent by a task waiting for system
283 resources like cpu, synchronous block I/O completion and swapping
284 in pages. Such statistics can help in setting a task's priorities
285 relative to other tasks for cpu, io, rss limits etc.
286
287 Say N if unsure.
288
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800289config TASK_XACCT
290 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
291 depends on TASKSTATS
292 help
293 Collect extended task accounting data and send the data
294 to userland for processing over the taskstats interface.
295
296 Say N if unsure.
297
298config TASK_IO_ACCOUNTING
299 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
300 depends on TASK_XACCT
301 help
302 Collect information on the number of bytes of storage I/O which this
303 task has caused.
304
305 Say N if unsure.
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307config AUDIT
308 bool "Auditing support"
Chris Wright804a6a42005-05-11 10:52:45 +0100309 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 help
311 Enable auditing infrastructure that can be used with another
312 kernel subsystem, such as SELinux (which requires this for
313 logging of avc messages output). Does not do system-call
314 auditing without CONFIG_AUDITSYSCALL.
315
316config AUDITSYSCALL
317 bool "Enable system-call auditing support"
Kumar Gala022382a2009-10-16 07:21:37 +0000318 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 default y if SECURITY_SELINUX
320 help
321 Enable low-overhead system-call auditing infrastructure that
322 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500323 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Eric Paris939a67f2009-12-17 20:12:06 -0500325config AUDIT_WATCH
326 def_bool y
327 depends on AUDITSYSCALL
328 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
Al Viro74c3cbe2007-07-22 08:04:18 -0400330config AUDIT_TREE
331 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400332 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500333 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400334
Mike Travisc903ff82009-01-15 12:28:29 -0800335menu "RCU Subsystem"
336
337choice
338 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700339 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800340
Mike Travisc903ff82009-01-15 12:28:29 -0800341config TREE_RCU
342 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700343 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800344 help
345 This option selects the RCU implementation that is
346 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700347 thousands of CPUs. It also scales down nicely to
348 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800349
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700350config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700351 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700352 depends on PREEMPT
353 help
354 This option selects the RCU implementation that is
355 designed for very large SMP systems with hundreds or
356 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700357 is also required. It also scales down nicely to
358 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700359
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700360config TINY_RCU
361 bool "UP-only small-memory-footprint RCU"
362 depends on !SMP
363 help
364 This option selects the RCU implementation that is
365 designed for UP systems from which real-time response
366 is not required. This option greatly reduces the
367 memory footprint of RCU.
368
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700369config TINY_PREEMPT_RCU
370 bool "Preemptible UP-only small-memory-footprint RCU"
371 depends on !SMP && PREEMPT
372 help
373 This option selects the RCU implementation that is designed
374 for real-time UP systems. This option greatly reduces the
375 memory footprint of RCU.
376
Mike Travisc903ff82009-01-15 12:28:29 -0800377endchoice
378
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700379config PREEMPT_RCU
380 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
381 help
382 This option enables preemptible-RCU code that is common between
383 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
384
Mike Travisc903ff82009-01-15 12:28:29 -0800385config RCU_TRACE
386 bool "Enable tracing for RCU"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700387 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800388 help
389 This option provides tracing in RCU which presents stats
390 in debugfs for debugging RCU implementation.
391
392 Say Y here if you want to enable RCU tracing
393 Say N if you are unsure.
394
395config RCU_FANOUT
396 int "Tree-based hierarchical RCU fanout value"
397 range 2 64 if 64BIT
398 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700399 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800400 default 64 if 64BIT
401 default 32 if !64BIT
402 help
403 This option controls the fanout of hierarchical implementations
404 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700405 large numbers of CPUs. This value must be at least the fourth
406 root of NR_CPUS, which allows NR_CPUS to be insanely large.
407 The default value of RCU_FANOUT should be used for production
408 systems, but if you are stress-testing the RCU implementation
409 itself, small RCU_FANOUT values allow you to test large-system
410 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800411
412 Select a specific number if testing RCU itself.
413 Take the default if unsure.
414
415config RCU_FANOUT_EXACT
416 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700417 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800418 default n
419 help
420 This option forces use of the exact RCU_FANOUT value specified,
421 regardless of imbalances in the hierarchy. This is useful for
422 testing RCU itself, and might one day be useful on systems with
423 strong NUMA behavior.
424
425 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
426
427 Say N if unsure.
428
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800429config RCU_FAST_NO_HZ
430 bool "Accelerate last non-dyntick-idle CPU's grace periods"
431 depends on TREE_RCU && NO_HZ && SMP
432 default n
433 help
434 This option causes RCU to attempt to accelerate grace periods
435 in order to allow the final CPU to enter dynticks-idle state
436 more quickly. On the other hand, this option increases the
437 overhead of the dynticks-idle checking, particularly on systems
438 with large numbers of CPUs.
439
440 Say Y if energy efficiency is critically important, particularly
441 if you have relatively few CPUs.
442
443 Say N if you are unsure.
444
Mike Travisc903ff82009-01-15 12:28:29 -0800445config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700446 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800447 select DEBUG_FS
448 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700449 This option provides tracing for the TREE_RCU and
450 TREE_PREEMPT_RCU implementations, permitting Makefile to
451 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800452
Paul E. McKenney24278d12010-09-27 17:25:23 -0700453config RCU_BOOST
454 bool "Enable RCU priority boosting"
455 depends on RT_MUTEXES && TINY_PREEMPT_RCU
456 default n
457 help
458 This option boosts the priority of preempted RCU readers that
459 block the current preemptible RCU grace period for too long.
460 This option also prevents heavy loads from blocking RCU
461 callback invocation for all flavors of RCU.
462
463 Say Y here if you are working with real-time apps or heavy loads
464 Say N here if you are unsure.
465
466config RCU_BOOST_PRIO
467 int "Real-time priority to boost RCU readers to"
468 range 1 99
469 depends on RCU_BOOST
470 default 1
471 help
472 This option specifies the real-time priority to which preempted
473 RCU readers are to be boosted. If you are working with CPU-bound
474 real-time applications, you should specify a priority higher then
475 the highest-priority CPU-bound application.
476
477 Specify the real-time priority, or take the default if unsure.
478
479config RCU_BOOST_DELAY
480 int "Milliseconds to delay boosting after RCU grace-period start"
481 range 0 3000
482 depends on RCU_BOOST
483 default 500
484 help
485 This option specifies the time to wait after the beginning of
486 a given grace period before priority-boosting preempted RCU
487 readers blocking that grace period. Note that any RCU reader
488 blocking an expedited RCU grace period is boosted immediately.
489
490 Accept the default if unsure.
491
Mike Travisc903ff82009-01-15 12:28:29 -0800492endmenu # "RCU Subsystem"
493
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700495 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 ---help---
497 This option enables the complete Linux kernel ".config" file
498 contents to be saved in the kernel. It provides documentation
499 of which kernel options are used in a running kernel or in an
500 on-disk kernel. This information can be extracted from the kernel
501 image file with the script scripts/extract-ikconfig and used as
502 input to rebuild the current kernel or to build another kernel.
503 It can also be extracted from a running kernel by reading
504 /proc/config.gz if enabled (below).
505
506config IKCONFIG_PROC
507 bool "Enable access to .config through /proc/config.gz"
508 depends on IKCONFIG && PROC_FS
509 ---help---
510 This option enables access to the kernel configuration file
511 through /proc/config.gz.
512
Alistair John Strachan794543a2007-05-08 00:31:15 -0700513config LOG_BUF_SHIFT
514 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
515 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700516 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700517 help
518 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700519 Examples:
520 17 => 128 KB
521 16 => 64 KB
522 15 => 32 KB
523 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700524 13 => 8 KB
525 12 => 4 KB
526
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800527#
528# Architectures with an unreliable sched_clock() should select this:
529#
530config HAVE_UNSTABLE_SCHED_CLOCK
531 bool
532
Li Zefan23964d22009-01-15 13:50:58 -0800533menuconfig CGROUPS
534 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800535 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700536 help
Li Zefan23964d22009-01-15 13:50:58 -0800537 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800538 use with process control subsystems such as Cpusets, CFS, memory
539 controls or device isolation.
540 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800541 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800542 - Documentation/cgroups/ (features for grouping, isolation
543 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700544
545 Say N if unsure.
546
Li Zefan23964d22009-01-15 13:50:58 -0800547if CGROUPS
548
Paul Menage006cb992007-10-18 23:39:43 -0700549config CGROUP_DEBUG
550 bool "Example debug cgroup subsystem"
551 depends on CGROUPS
Paul Menage418d7d82008-04-29 01:00:05 -0700552 default n
Paul Menage006cb992007-10-18 23:39:43 -0700553 help
554 This option enables a simple cgroup subsystem that
555 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800556 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700557
Li Zefan23964d22009-01-15 13:50:58 -0800558 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700559
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700560config CGROUP_NS
Li Zefan23964d22009-01-15 13:50:58 -0800561 bool "Namespace cgroup subsystem"
562 depends on CGROUPS
563 help
564 Provides a simple namespace cgroup subsystem to
565 provide hierarchical naming of sets of namespaces,
566 for instance virtual servers and checkpoint/restart
567 jobs.
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700568
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700569config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800570 bool "Freezer cgroup subsystem"
571 depends on CGROUPS
572 help
573 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700574 cgroup.
575
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700576config CGROUP_DEVICE
577 bool "Device controller for cgroups"
578 depends on CGROUPS && EXPERIMENTAL
579 help
580 Provides a cgroup implementing whitelists for devices which
581 a process in the cgroup can mknod or open.
582
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583config CPUSETS
584 bool "Cpuset support"
Paul Menagedb7f47c2009-04-02 16:57:55 -0700585 depends on CGROUPS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700587 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 allow dynamically partitioning a system into sets of CPUs and
589 Memory Nodes and assigning tasks to run only within those sets.
590 This is primarily useful on large SMP or NUMA systems.
591
592 Say N if unsure.
593
Li Zefan23964d22009-01-15 13:50:58 -0800594config PROC_PID_CPUSET
595 bool "Include legacy /proc/<pid>/cpuset file"
596 depends on CPUSETS
597 default y
598
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100599config CGROUP_CPUACCT
600 bool "Simple CPU accounting cgroup subsystem"
601 depends on CGROUPS
602 help
603 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800604 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100605
Pavel Emelianove552b662008-02-07 00:13:49 -0800606config RESOURCE_COUNTERS
607 bool "Resource counters"
608 help
609 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800610 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800611 depends on CGROUPS
612
Balbir Singh00f0b822008-03-04 14:28:39 -0800613config CGROUP_MEM_RES_CTLR
614 bool "Memory Resource Controller for Control Groups"
615 depends on CGROUPS && RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700616 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800617 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700618 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100619 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800620
621 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700622 associated with each page of memory in the system. By this,
623 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
624 usage tracking struct at boot. Total amount of this is printed out
625 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800626
627 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700628 sure you need the memory resource controller. Even when you enable
629 this, you can set "cgroup_disable=memory" at your boot option to
630 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800631 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800632
Balbir Singhcf475ad2008-04-29 01:00:16 -0700633 This config option also selects MM_OWNER config option, which
634 could in turn add some fork/exit overhead.
635
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800636config CGROUP_MEM_RES_CTLR_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700637 bool "Memory Resource Controller Swap Extension"
638 depends on CGROUP_MEM_RES_CTLR && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800639 help
640 Add swap management feature to memory resource controller. When you
641 enable this, you can limit mem+swap usage per cgroup. In other words,
642 when you disable this, memory resource controller has no cares to
643 usage of swap...a process can exhaust all of the swap. This extension
644 is useful when you want to avoid exhaustion swap but this itself
645 adds more overheads and consumes memory for remembering information.
646 Especially if you use 32bit system or small memory system, please
647 be careful about enabling this. When memory resource controller
648 is disabled by boot option, this will be automatically disabled and
649 there will be no overhead from this. Even when you set this config=y,
650 if boot option "noswapaccount" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700651 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
652 size is 4096bytes, 512k per 1Gbytes of swap.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800653
Dhaval Giani7c941432010-01-20 13:26:18 +0100654menuconfig CGROUP_SCHED
655 bool "Group CPU scheduler"
656 depends on EXPERIMENTAL && CGROUPS
657 default n
658 help
659 This feature lets CPU scheduler recognize task groups and control CPU
660 bandwidth allocation to such task groups. It uses cgroups to group
661 tasks.
662
663if CGROUP_SCHED
664config FAIR_GROUP_SCHED
665 bool "Group scheduling for SCHED_OTHER"
666 depends on CGROUP_SCHED
667 default CGROUP_SCHED
668
669config RT_GROUP_SCHED
670 bool "Group scheduling for SCHED_RR/FIFO"
671 depends on EXPERIMENTAL
672 depends on CGROUP_SCHED
673 default n
674 help
675 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800676 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100677 schedule realtime tasks for non-root users until you allocate
678 realtime bandwidth for them.
679 See Documentation/scheduler/sched-rt-group.txt for more information.
680
681endif #CGROUP_SCHED
682
Vivek Goyalafc24d42010-04-26 19:27:56 +0200683config BLK_CGROUP
684 tristate "Block IO controller"
685 depends on CGROUPS && BLOCK
686 default n
687 ---help---
688 Generic block IO controller cgroup interface. This is the common
689 cgroup interface which should be used by various IO controlling
690 policies.
691
692 Currently, CFQ IO scheduler uses it to recognize task groups and
693 control disk bandwidth allocation (proportional time slice allocation)
694 to such task groups.
695
696 This option only enables generic Block IO controller infrastructure.
697 One needs to also enable actual IO controlling logic in CFQ for it
698 to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
699
700 See Documentation/cgroups/blkio-controller.txt for more information.
701
702config DEBUG_BLK_CGROUP
703 bool "Enable Block IO controller debugging"
704 depends on BLK_CGROUP
705 default n
706 ---help---
707 Enable some debugging help. Currently it exports additional stat
708 files in a cgroup which can be useful for debugging.
709
Li Zefan23964d22009-01-15 13:50:58 -0800710endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800711
Li Zefan23964d22009-01-15 13:50:58 -0800712config MM_OWNER
713 bool
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800714
Kay Sievers88a22c92006-09-14 11:23:28 +0200715config SYSFS_DEPRECATED
Ingo Molnard47846c2008-03-04 14:54:47 +0100716 bool
717
718config SYSFS_DEPRECATED_V2
Uwe Kleine-König9e9868a2009-12-03 19:58:00 +0100719 bool "enable deprecated sysfs features to support old userspace tools"
Randy Dunlap9148fe82007-12-31 10:05:34 -0800720 depends on SYSFS
Kay Sieversf6ee6492009-04-16 19:56:37 +0200721 default n
Ingo Molnard47846c2008-03-04 14:54:47 +0100722 select SYSFS_DEPRECATED
Kay Sievers88a22c92006-09-14 11:23:28 +0200723 help
Kay Sieversfce3e802008-11-01 14:03:00 +0100724 This option switches the layout of sysfs to the deprecated
Kay Sieversf6ee6492009-04-16 19:56:37 +0200725 version. Do not use it on recent distributions.
Kay Sievers88a22c92006-09-14 11:23:28 +0200726
Kay Sieversfce3e802008-11-01 14:03:00 +0100727 The current sysfs layout features a unified device tree at
728 /sys/devices/, which is able to express a hierarchy between
729 class devices. If the deprecated option is set to Y, the
730 unified device tree is split into a bus device tree at
731 /sys/devices/ and several individual class device trees at
732 /sys/class/. The class and bus devices will be connected by
733 "<subsystem>:<name>" and the "device" links. The "block"
734 class devices, will not show up in /sys/class/block/. Some
735 subsystems will suppress the creation of some devices which
736 depend on the unified device tree.
Kay Sievers88a22c92006-09-14 11:23:28 +0200737
Kay Sieversfce3e802008-11-01 14:03:00 +0100738 This option is not a pure compatibility option that can
739 be safely enabled on newer distributions. It will change the
740 layout of sysfs to the non-extensible deprecated version,
741 and disable some features, which can not be exported without
742 confusing older userspace tools. Since 2007/2008 all major
743 distributions do not enable this option, and ship no tools which
744 depend on the deprecated layout or this option.
745
746 If you are using a new kernel on an older distribution, or use
747 older userspace tools, you might need to say Y here. Do not say Y,
748 if the original kernel, that came with your distribution, has
749 this option set to N.
Kay Sievers88a22c92006-09-14 11:23:28 +0200750
Jens Axboeb86ff982006-03-23 19:56:55 +0100751config RELAY
752 bool "Kernel->user space relay support (formerly relayfs)"
753 help
754 This option enables support for relay interface support in
755 certain file systems (such as debugfs).
756 It is designed to provide an efficient mechanism for tools and
757 facilities to relay large amounts of data from kernel space to
758 user space.
759
760 If unsure, say N.
761
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800762config NAMESPACES
763 bool "Namespaces support" if EMBEDDED
764 default !EMBEDDED
765 help
766 Provides the way to make tasks work with different objects using
767 the same id. For example same IPC id may refer to different objects
768 or same user id or pid may refer to different tasks when used in
769 different namespaces.
770
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800771config UTS_NS
772 bool "UTS namespace"
773 depends on NAMESPACES
774 help
775 In this namespace tasks see different info provided with the
776 uname() system call
777
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800778config IPC_NS
779 bool "IPC namespace"
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700780 depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800781 help
782 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700783 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800784
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800785config USER_NS
786 bool "User namespace (EXPERIMENTAL)"
787 depends on NAMESPACES && EXPERIMENTAL
788 help
789 This allows containers, i.e. vservers, to use user namespaces
790 to provide different user info for different servers.
791 If unsure, say N.
792
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800793config PID_NS
794 bool "PID Namespaces (EXPERIMENTAL)"
795 default n
796 depends on NAMESPACES && EXPERIMENTAL
797 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300798 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100799 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800800 pid namespaces. This is a building block of containers.
801
802 Unless you want to work with an experimental feature
803 say N here.
804
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800805config NET_NS
806 bool "Network namespace"
807 default n
808 depends on NAMESPACES && EXPERIMENTAL && NET
809 help
810 Allow user space to create what appear to be multiple instances
811 of the network stack.
812
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800813config BLK_DEV_INITRD
814 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
815 depends on BROKEN || !FRV
816 help
817 The initial RAM filesystem is a ramfs which is loaded by the
818 boot loader (loadlin or lilo) and that is mounted as root
819 before the normal boot procedure. It is typically used to
820 load modules needed to mount the "real" root file system,
821 etc. See <file:Documentation/initrd.txt> for details.
822
823 If RAM disk support (BLK_DEV_RAM) is also included, this
824 also enables initial RAM disk (initrd) support and adds
825 15 Kbytes (more on some other architectures) to the kernel size.
826
827 If unsure say Y.
828
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800829if BLK_DEV_INITRD
830
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200831source "usr/Kconfig"
832
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800833endif
834
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800835config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200836 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800837 default y
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800838 help
839 Enabling this option will pass "-Os" instead of "-O2" to gcc
840 resulting in a smaller kernel.
841
jkacur775a7222008-07-16 00:31:16 +0200842 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800843
Randy Dunlap08470622006-09-30 23:28:13 -0700844config SYSCTL
845 bool
846
Randy Dunlapb943c462009-03-10 12:55:46 -0700847config ANON_INODES
848 bool
849
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850menuconfig EMBEDDED
851 bool "Configure standard kernel features (for small systems)"
852 help
853 This option allows certain base kernel options and settings
854 to be disabled or tweaked. This is for specialized
855 environments which can tolerate a "non-standard" kernel.
856 Only use this if you really know what you are doing.
857
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700858config UID16
859 bool "Enable 16-bit UID system calls" if EMBEDDED
David S. Miller09337f52008-04-26 03:17:12 -0700860 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700861 default y
862 help
863 This enables the legacy 16-bit UID syscall wrappers.
864
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700865config SYSCTL_SYSCALL
Randy Dunlap08470622006-09-30 23:28:13 -0700866 bool "Sysctl syscall support" if EMBEDDED
Eric W. Biederman26a70342009-11-05 05:26:41 -0800867 depends on PROC_SYSCTL
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800868 default y
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700869 select SYSCTL
870 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800871 sys_sysctl uses binary paths that have been found challenging
872 to properly maintain and use. The interface in /proc/sys
873 using paths with ascii names is now the primary path to this
874 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700875
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800876 Almost nothing using the binary sysctl interface so if you are
877 trying to save some space it is probably safe to disable this,
878 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700879
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800880 If unsure say Y here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700881
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882config KALLSYMS
Jesper Juhl979c6a12006-12-12 19:25:11 +0100883 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 default y
885 help
886 Say Y here to let the kernel print out symbolic crash information and
887 symbolic stack backtraces. This increases the size of the kernel
888 somewhat, as all symbols have to be loaded into the kernel image.
889
890config KALLSYMS_ALL
891 bool "Include all symbols in kallsyms"
892 depends on DEBUG_KERNEL && KALLSYMS
893 help
894 Normally kallsyms only contains the symbols of functions, for nicer
895 OOPS messages. Some debuggers can use kallsyms for other
Jesper Juhlf9f97bc2005-07-20 05:43:05 +0200896 symbols too: say Y here to include all symbols, if you need them
897 and you don't care about adding 300k to the size of your kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898
899 Say N.
900
901config KALLSYMS_EXTRA_PASS
902 bool "Do an extra kallsyms pass"
903 depends on KALLSYMS
904 help
905 If kallsyms is not working correctly, the build will fail with
906 inconsistent kallsyms data. If that occurs, log a bug report and
907 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
908 Always say N here unless you find a bug in kallsyms, which must be
909 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
910 you wait for kallsyms to be fixed.
911
Matt Mackalld59745c2005-05-01 08:59:02 -0700912
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -0800913config HOTPLUG
914 bool "Support for hot-pluggable devices" if EMBEDDED
915 default y
916 help
917 This option is provided for the case where no hotplug or uevent
918 capabilities is wanted by the kernel. You should only consider
919 disabling this option for embedded systems that do not use modules, a
920 dynamic /dev tree, or dynamic device discovery. Just say Y.
921
Matt Mackalld59745c2005-05-01 08:59:02 -0700922config PRINTK
923 default y
924 bool "Enable support for printk" if EMBEDDED
925 help
926 This option enables normal printk support. Removing it
927 eliminates most of the message strings from the kernel image
928 and makes the kernel more or less silent. As this makes it
929 very difficult to diagnose system problems, saying N here is
930 strongly discouraged.
931
Matt Mackallc8538a72005-05-01 08:59:01 -0700932config BUG
933 bool "BUG() support" if EMBEDDED
934 default y
935 help
936 Disabling this option eliminates support for BUG and WARN, reducing
937 the size of your kernel image and potentially quietly ignoring
938 numerous fatal conditions. You should only consider disabling this
939 option for embedded systems with no facilities for reporting errors.
940 Just say Y.
941
Matt Mackall708e9a72006-01-08 01:05:25 -0800942config ELF_CORE
943 default y
944 bool "Enable ELF core dumps" if EMBEDDED
945 help
946 Enable support for generating core dumps. Disabling saves about 4k.
947
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +0200948config PCSPKR_PLATFORM
949 bool "Enable PC-Speaker support" if EMBEDDED
950 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
951 default y
952 help
953 This option allows to disable the internal PC-Speaker
954 support, saving some memory.
955
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956config BASE_FULL
957 default y
958 bool "Enable full-sized data structures for core" if EMBEDDED
959 help
960 Disabling this option reduces the size of miscellaneous core
961 kernel data structures. This saves memory on small machines,
962 but may reduce performance.
963
964config FUTEX
965 bool "Enable futex support" if EMBEDDED
966 default y
Ingo Molnar23f78d42006-06-27 02:54:53 -0700967 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 help
969 Disabling this option will cause the kernel to be built without
970 support for "fast userspace mutexes". The resulting kernel may not
971 run glibc-based applications correctly.
972
973config EPOLL
974 bool "Enable eventpoll support" if EMBEDDED
975 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700976 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 help
978 Disabling this option will cause the kernel to be built without
979 support for epoll family of system calls.
980
Davide Libenzifba2afa2007-05-10 22:23:13 -0700981config SIGNALFD
982 bool "Enable signalfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700983 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -0700984 default y
985 help
986 Enable the signalfd() system call that allows to receive signals
987 on a file descriptor.
988
989 If unsure, say Y.
990
Davide Libenzib215e282007-05-10 22:23:16 -0700991config TIMERFD
992 bool "Enable timerfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700993 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -0700994 default y
995 help
996 Enable the timerfd() system call that allows to receive timer
997 events on a file descriptor.
998
999 If unsure, say Y.
1000
Davide Libenzie1ad7462007-05-10 22:23:19 -07001001config EVENTFD
1002 bool "Enable eventfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001003 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001004 default y
1005 help
1006 Enable the eventfd() system call that allows to receive both
1007 kernel notification (ie. KAIO) or userspace notifications.
1008
1009 If unsure, say Y.
1010
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011config SHMEM
1012 bool "Use full shmem filesystem" if EMBEDDED
1013 default y
1014 depends on MMU
1015 help
1016 The shmem is an internal filesystem used to manage shared memory.
1017 It is backed by swap and manages resource limits. It is also exported
1018 to userspace as tmpfs if TMPFS is enabled. Disabling this
1019 option replaces shmem and tmpfs with the much simpler ramfs code,
1020 which may be appropriate on small systems without swap.
1021
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001022config AIO
1023 bool "Enable AIO support" if EMBEDDED
1024 default y
1025 help
1026 This option enables POSIX asynchronous I/O which may by used
1027 by some high performance threaded applications. Disabling
1028 this option saves about 7k.
1029
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001030config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001031 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001032 help
1033 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001034
Peter Zijlstra906010b2009-09-21 16:08:49 +02001035config PERF_USE_VMALLOC
1036 bool
1037 help
1038 See tools/perf/design.txt for details
1039
Ingo Molnar57c0c152009-09-21 12:20:38 +02001040menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001041
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001042config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001043 bool "Kernel performance events and counters"
1044 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001045 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001046 select ANON_INODES
Thomas Gleixner0793a612008-12-04 20:12:29 +01001047 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001048 Enable kernel support for various performance events provided
1049 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001050
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001051 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001052 use of generic tracepoints.
1053
1054 Most modern CPUs support performance events via performance
1055 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001056 types of hw events: such as instructions executed, cachemisses
1057 suffered, or branches mis-predicted - without slowing down the
1058 kernel or applications. These registers can also trigger interrupts
1059 when a threshold number of events have passed - and can thus be
1060 used to profile the code that runs on that CPU.
1061
Ingo Molnar57c0c152009-09-21 12:20:38 +02001062 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001063 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001064 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001065 provides per task and per CPU counters, and it provides event
1066 capabilities on top of those.
1067
1068 Say Y if unsure.
1069
Ingo Molnar57c0c152009-09-21 12:20:38 +02001070config PERF_COUNTERS
1071 bool "Kernel performance counters (old config option)"
1072 depends on HAVE_PERF_EVENTS
1073 help
1074 This config has been obsoleted by the PERF_EVENTS
1075 config option - please see that one for details.
1076
1077 It has no effect on the kernel whether you enable
1078 it or not, it is a compatibility placeholder.
1079
1080 Say N if unsure.
1081
Peter Zijlstra906010b2009-09-21 16:08:49 +02001082config DEBUG_PERF_USE_VMALLOC
1083 default n
1084 bool "Debug: use vmalloc to back perf mmap() buffers"
1085 depends on PERF_EVENTS && DEBUG_KERNEL
1086 select PERF_USE_VMALLOC
1087 help
1088 Use vmalloc memory to back perf mmap() buffers.
1089
1090 Mostly useful for debugging the vmalloc code on platforms
1091 that don't require it.
1092
1093 Say N if unsure.
1094
Thomas Gleixner0793a612008-12-04 20:12:29 +01001095endmenu
1096
Christoph Lameterf8891e52006-06-30 01:55:45 -07001097config VM_EVENT_COUNTERS
1098 default y
1099 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1100 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001101 VM event counters are needed for event counts to be shown.
1102 This option allows the disabling of the VM event counters
1103 on EMBEDDED systems. /proc/vmstat will only show page counts
1104 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001105
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001106config PCI_QUIRKS
1107 default y
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001108 bool "Enable PCI quirk workarounds" if EMBEDDED
1109 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001110 help
1111 This enables workarounds for various PCI chipset
1112 bugs/quirks. Disable this only if your target machine is
1113 unaffected by PCI quirks.
1114
Christoph Lameter41ecc552007-05-09 02:32:44 -07001115config SLUB_DEBUG
1116 default y
1117 bool "Enable SLUB debugging support" if EMBEDDED
Christoph Lameterf6acb632008-04-29 16:16:06 -07001118 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001119 help
1120 SLUB has extensive debug support features. Disabling these can
1121 result in significant savings in code size. This also disables
1122 SLUB sysfs support. /sys/slab will not exist and there will be
1123 no support for cache validation etc.
1124
Randy Dunlapb943c462009-03-10 12:55:46 -07001125config COMPAT_BRK
1126 bool "Disable heap randomization"
1127 default y
1128 help
1129 Randomizing heap placement makes heap exploits harder, but it
1130 also breaks ancient binaries (including anything libc5 based).
1131 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001132 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001133 /proc/sys/kernel/randomize_va_space to 2.
1134
1135 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1136
Christoph Lameter81819f02007-05-06 14:49:36 -07001137choice
1138 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001139 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001140 help
1141 This option allows to select a slab allocator.
1142
1143config SLAB
1144 bool "SLAB"
1145 help
1146 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001147 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001148 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001149
1150config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001151 bool "SLUB (Unqueued Allocator)"
1152 help
1153 SLUB is a slab allocator that minimizes cache line usage
1154 instead of managing queues of cached objects (SLAB approach).
1155 Per cpu caching is realized using slabs of objects instead
1156 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001157 and has enhanced diagnostics. SLUB is the default choice for
1158 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001159
1160config SLOB
Paul Mundt84a01c22007-07-15 23:38:24 -07001161 depends on EMBEDDED
Christoph Lameter81819f02007-05-06 14:49:36 -07001162 bool "SLOB (Simple Allocator)"
1163 help
Matt Mackall37291452008-02-04 22:29:38 -08001164 SLOB replaces the stock allocator with a drastically simpler
1165 allocator. SLOB is generally more space efficient but
1166 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001167
1168endchoice
1169
Jie Zhangea637632009-12-14 18:00:02 -08001170config MMAP_ALLOW_UNINITIALIZED
1171 bool "Allow mmapped anonymous memory to be uninitialized"
1172 depends on EMBEDDED && !MMU
1173 default n
1174 help
1175 Normally, and according to the Linux spec, anonymous memory obtained
1176 from mmap() has it's contents cleared before it is passed to
1177 userspace. Enabling this config option allows you to request that
1178 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1179 providing a huge performance boost. If this option is not enabled,
1180 then the flag will be ignored.
1181
1182 This is taken advantage of by uClibc's malloc(), and also by
1183 ELF-FDPIC binfmt's brk and stack allocator.
1184
1185 Because of the obvious security issues, this option should only be
1186 enabled on embedded devices where you control what is run in
1187 userspace. Since that isn't generally a problem on no-MMU systems,
1188 it is normally safe to say Y here.
1189
1190 See Documentation/nommu-mmap.txt for more information.
1191
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001192config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001193 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001194 help
1195 Say Y here to enable the extended profiling support mechanisms used
1196 by profilers such as OProfile.
1197
Ingo Molnar5f87f112008-07-23 14:15:22 +02001198#
1199# Place an empty function call at each tracepoint site. Can be
1200# dynamically changed for a probe function.
1201#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001202config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001203 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001204
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001205source "arch/Kconfig"
1206
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207endmenu # General setup
1208
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001209config HAVE_GENERIC_DMA_COHERENT
1210 bool
1211 default n
1212
Linus Torvalds158a9622008-01-02 13:04:48 -08001213config SLABINFO
1214 bool
1215 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001216 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001217 default y
1218
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001219config RT_MUTEXES
1220 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001221
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222config BASE_SMALL
1223 int
1224 default 0 if BASE_FULL
1225 default 1 if !BASE_FULL
1226
Jan Engelhardt66da5732007-07-15 23:39:29 -07001227menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 bool "Enable loadable module support"
1229 help
1230 Kernel modules are small pieces of compiled code which can
1231 be inserted in the running kernel, rather than being
1232 permanently built into the kernel. You use the "modprobe"
1233 tool to add (and sometimes remove) them. If you say Y here,
1234 many parts of the kernel can be built as modules (by
1235 answering M instead of Y where indicated): this is most
1236 useful for infrequently used options which are not required
1237 for booting. For more information, see the man pages for
1238 modprobe, lsmod, modinfo, insmod and rmmod.
1239
1240 If you say Y here, you will need to run "make
1241 modules_install" to put the modules under /lib/modules/
1242 where modprobe can find them (you may need to be root to do
1243 this).
1244
1245 If unsure, say Y.
1246
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001247if MODULES
1248
Linus Torvalds826e4502008-05-04 17:04:16 -07001249config MODULE_FORCE_LOAD
1250 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001251 default n
1252 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001253 Allow loading of modules without version information (ie. modprobe
1254 --force). Forced module loading sets the 'F' (forced) taint flag and
1255 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001256
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257config MODULE_UNLOAD
1258 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 help
1260 Without this option you will not be able to unload any
1261 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001262 anyway), which makes your kernel smaller, faster
1263 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264
1265config MODULE_FORCE_UNLOAD
1266 bool "Forced module unloading"
1267 depends on MODULE_UNLOAD && EXPERIMENTAL
1268 help
1269 This option allows you to force a module to unload, even if the
1270 kernel believes it is unsafe: the kernel will remove the module
1271 without waiting for anyone to stop using it (using the -f option to
1272 rmmod). This is mainly for kernel developers and desperate users.
1273 If unsure, say N.
1274
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001276 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 help
1278 Usually, you have to use modules compiled with your kernel.
1279 Saying Y here makes it sometimes possible to use modules
1280 compiled for different kernels, by adding enough information
1281 to the modules to (hopefully) spot any changes which would
1282 make them incompatible with the kernel you are running. If
1283 unsure, say N.
1284
1285config MODULE_SRCVERSION_ALL
1286 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 help
1288 Modules which contain a MODULE_VERSION get an extra "srcversion"
1289 field inserted into their modinfo section, which contains a
1290 sum of the source files which made it. This helps maintainers
1291 see exactly which source was used to build a module (since
1292 others sometimes change the module source without updating
1293 the version). With this option, such a "srcversion" field
1294 will be created for all modules. If unsure, say N.
1295
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001296endif # MODULES
1297
Rusty Russell98a79d62008-12-13 21:19:41 +10301298config INIT_ALL_POSSIBLE
1299 bool
1300 help
1301 Back when each arch used to define their own cpu_online_map and
1302 cpu_possible_map, some of them chose to initialize cpu_possible_map
1303 with all 1s, and others with all 0s. When they were centralised,
1304 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001305 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301306
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307config STOP_MACHINE
1308 bool
1309 default y
1310 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1311 help
1312 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001313
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001314source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001315
1316config PREEMPT_NOTIFIERS
1317 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001318
Steffen Klassert16295be2010-01-06 19:47:10 +11001319config PADATA
1320 depends on SMP
1321 bool
1322
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001323source "kernel/Kconfig.locks"