blob: 313506d8be6ea54bbacf78f0deb1b7d9eead4c92 [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' Giarrussob2670eac2006-10-19 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47 drivers that have been replaced by something else, and/or are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 Wright804a6a492005-05-11 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,
Amy Griffisf368c07d2006-04-07 16:55:56 -0400323 such as SELinux. To use audit's filesystem watch feature, please
324 ensure that INOTIFY is configured.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
Al Viro74c3cbe2007-07-22 08:04:18 -0400326config AUDIT_TREE
327 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400328 depends on AUDITSYSCALL
329 select INOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400330
Mike Travisc903ff82009-01-15 12:28:29 -0800331menu "RCU Subsystem"
332
333choice
334 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700335 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800336
Mike Travisc903ff82009-01-15 12:28:29 -0800337config TREE_RCU
338 bool "Tree-based hierarchical RCU"
339 help
340 This option selects the RCU implementation that is
341 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700342 thousands of CPUs. It also scales down nicely to
343 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800344
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700345config TREE_PREEMPT_RCU
346 bool "Preemptable tree-based hierarchical RCU"
347 depends on PREEMPT
348 help
349 This option selects the RCU implementation that is
350 designed for very large SMP systems with hundreds or
351 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700352 is also required. It also scales down nicely to
353 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700354
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700355config TINY_RCU
356 bool "UP-only small-memory-footprint RCU"
357 depends on !SMP
358 help
359 This option selects the RCU implementation that is
360 designed for UP systems from which real-time response
361 is not required. This option greatly reduces the
362 memory footprint of RCU.
363
Mike Travisc903ff82009-01-15 12:28:29 -0800364endchoice
365
366config RCU_TRACE
367 bool "Enable tracing for RCU"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700368 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800369 help
370 This option provides tracing in RCU which presents stats
371 in debugfs for debugging RCU implementation.
372
373 Say Y here if you want to enable RCU tracing
374 Say N if you are unsure.
375
376config RCU_FANOUT
377 int "Tree-based hierarchical RCU fanout value"
378 range 2 64 if 64BIT
379 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700380 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800381 default 64 if 64BIT
382 default 32 if !64BIT
383 help
384 This option controls the fanout of hierarchical implementations
385 of RCU, allowing RCU to work efficiently on machines with
386 large numbers of CPUs. This value must be at least the cube
387 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
388 systems and up to 262,144 for 64-bit systems.
389
390 Select a specific number if testing RCU itself.
391 Take the default if unsure.
392
393config RCU_FANOUT_EXACT
394 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700395 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800396 default n
397 help
398 This option forces use of the exact RCU_FANOUT value specified,
399 regardless of imbalances in the hierarchy. This is useful for
400 testing RCU itself, and might one day be useful on systems with
401 strong NUMA behavior.
402
403 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
404
405 Say N if unsure.
406
407config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700408 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800409 select DEBUG_FS
410 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700411 This option provides tracing for the TREE_RCU and
412 TREE_PREEMPT_RCU implementations, permitting Makefile to
413 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800414
Mike Travisc903ff82009-01-15 12:28:29 -0800415endmenu # "RCU Subsystem"
416
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700418 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 ---help---
420 This option enables the complete Linux kernel ".config" file
421 contents to be saved in the kernel. It provides documentation
422 of which kernel options are used in a running kernel or in an
423 on-disk kernel. This information can be extracted from the kernel
424 image file with the script scripts/extract-ikconfig and used as
425 input to rebuild the current kernel or to build another kernel.
426 It can also be extracted from a running kernel by reading
427 /proc/config.gz if enabled (below).
428
429config IKCONFIG_PROC
430 bool "Enable access to .config through /proc/config.gz"
431 depends on IKCONFIG && PROC_FS
432 ---help---
433 This option enables access to the kernel configuration file
434 through /proc/config.gz.
435
Alistair John Strachan794543a2007-05-08 00:31:15 -0700436config LOG_BUF_SHIFT
437 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
438 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700439 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700440 help
441 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700442 Examples:
443 17 => 128 KB
444 16 => 64 KB
445 15 => 32 KB
446 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700447 13 => 8 KB
448 12 => 4 KB
449
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800450#
451# Architectures with an unreliable sched_clock() should select this:
452#
453config HAVE_UNSTABLE_SCHED_CLOCK
454 bool
455
456config GROUP_SCHED
457 bool "Group CPU scheduler"
458 depends on EXPERIMENTAL
459 default n
460 help
461 This feature lets CPU scheduler recognize task groups and control CPU
462 bandwidth allocation to such task groups.
463 In order to create a group from arbitrary set of processes, use
464 CONFIG_CGROUPS. (See Control Group support.)
465
466config FAIR_GROUP_SCHED
467 bool "Group scheduling for SCHED_OTHER"
468 depends on GROUP_SCHED
469 default GROUP_SCHED
470
471config RT_GROUP_SCHED
472 bool "Group scheduling for SCHED_RR/FIFO"
473 depends on EXPERIMENTAL
474 depends on GROUP_SCHED
475 default n
476 help
477 This feature lets you explicitly allocate real CPU bandwidth
478 to users or control groups (depending on the "Basis for grouping tasks"
479 setting below. If enabled, it will also make it impossible to
480 schedule realtime tasks for non-root users until you allocate
481 realtime bandwidth for them.
482 See Documentation/scheduler/sched-rt-group.txt for more information.
483
484choice
485 depends on GROUP_SCHED
486 prompt "Basis for grouping tasks"
487 default USER_SCHED
488
489config USER_SCHED
490 bool "user id"
491 help
492 This option will choose userid as the basis for grouping
493 tasks, thus providing equal CPU bandwidth to each user.
494
495config CGROUP_SCHED
496 bool "Control groups"
497 depends on CGROUPS
498 help
499 This option allows you to create arbitrary task groups
500 using the "cgroup" pseudo filesystem and control
501 the cpu bandwidth allocated to each such task group.
Li Zefan45ce80f2009-01-15 13:50:59 -0800502 Refer to Documentation/cgroups/cgroups.txt for more
503 information on "cgroup" pseudo filesystem.
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800504
505endchoice
506
Li Zefan23964d22009-01-15 13:50:58 -0800507menuconfig CGROUPS
508 boolean "Control Group support"
Paul Menageddbcc7e2007-10-18 23:39:30 -0700509 help
Li Zefan23964d22009-01-15 13:50:58 -0800510 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800511 use with process control subsystems such as Cpusets, CFS, memory
512 controls or device isolation.
513 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800514 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800515 - Documentation/cgroups/ (features for grouping, isolation
516 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700517
518 Say N if unsure.
519
Li Zefan23964d22009-01-15 13:50:58 -0800520if CGROUPS
521
Paul Menage006cb992007-10-18 23:39:43 -0700522config CGROUP_DEBUG
523 bool "Example debug cgroup subsystem"
524 depends on CGROUPS
Paul Menage418d7d82008-04-29 01:00:05 -0700525 default n
Paul Menage006cb992007-10-18 23:39:43 -0700526 help
527 This option enables a simple cgroup subsystem that
528 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800529 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700530
Li Zefan23964d22009-01-15 13:50:58 -0800531 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700532
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700533config CGROUP_NS
Li Zefan23964d22009-01-15 13:50:58 -0800534 bool "Namespace cgroup subsystem"
535 depends on CGROUPS
536 help
537 Provides a simple namespace cgroup subsystem to
538 provide hierarchical naming of sets of namespaces,
539 for instance virtual servers and checkpoint/restart
540 jobs.
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700541
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700542config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800543 bool "Freezer cgroup subsystem"
544 depends on CGROUPS
545 help
546 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700547 cgroup.
548
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700549config CGROUP_DEVICE
550 bool "Device controller for cgroups"
551 depends on CGROUPS && EXPERIMENTAL
552 help
553 Provides a cgroup implementing whitelists for devices which
554 a process in the cgroup can mknod or open.
555
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556config CPUSETS
557 bool "Cpuset support"
Paul Menagedb7f47c2009-04-02 16:57:55 -0700558 depends on CGROUPS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700560 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 allow dynamically partitioning a system into sets of CPUs and
562 Memory Nodes and assigning tasks to run only within those sets.
563 This is primarily useful on large SMP or NUMA systems.
564
565 Say N if unsure.
566
Li Zefan23964d22009-01-15 13:50:58 -0800567config PROC_PID_CPUSET
568 bool "Include legacy /proc/<pid>/cpuset file"
569 depends on CPUSETS
570 default y
571
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100572config CGROUP_CPUACCT
573 bool "Simple CPU accounting cgroup subsystem"
574 depends on CGROUPS
575 help
576 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800577 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100578
Pavel Emelianove552b662008-02-07 00:13:49 -0800579config RESOURCE_COUNTERS
580 bool "Resource counters"
581 help
582 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800583 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800584 depends on CGROUPS
585
Balbir Singh00f0b822008-03-04 14:28:39 -0800586config CGROUP_MEM_RES_CTLR
587 bool "Memory Resource Controller for Control Groups"
588 depends on CGROUPS && RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700589 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800590 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700591 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100592 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800593
594 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700595 associated with each page of memory in the system. By this,
596 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
597 usage tracking struct at boot. Total amount of this is printed out
598 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800599
600 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700601 sure you need the memory resource controller. Even when you enable
602 this, you can set "cgroup_disable=memory" at your boot option to
603 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800604 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800605
Balbir Singhcf475ad2008-04-29 01:00:16 -0700606 This config option also selects MM_OWNER config option, which
607 could in turn add some fork/exit overhead.
608
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800609config CGROUP_MEM_RES_CTLR_SWAP
610 bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)"
611 depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL
612 help
613 Add swap management feature to memory resource controller. When you
614 enable this, you can limit mem+swap usage per cgroup. In other words,
615 when you disable this, memory resource controller has no cares to
616 usage of swap...a process can exhaust all of the swap. This extension
617 is useful when you want to avoid exhaustion swap but this itself
618 adds more overheads and consumes memory for remembering information.
619 Especially if you use 32bit system or small memory system, please
620 be careful about enabling this. When memory resource controller
621 is disabled by boot option, this will be automatically disabled and
622 there will be no overhead from this. Even when you set this config=y,
623 if boot option "noswapaccount" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700624 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
625 size is 4096bytes, 512k per 1Gbytes of swap.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800626
Li Zefan23964d22009-01-15 13:50:58 -0800627endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800628
Li Zefan23964d22009-01-15 13:50:58 -0800629config MM_OWNER
630 bool
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800631
Kay Sievers88a22c92006-09-14 11:23:28 +0200632config SYSFS_DEPRECATED
Ingo Molnard47846c2008-03-04 14:54:47 +0100633 bool
634
635config SYSFS_DEPRECATED_V2
Uwe Kleine-König9e9868a2009-12-03 19:58:00 +0100636 bool "enable deprecated sysfs features to support old userspace tools"
Randy Dunlap9148fe82007-12-31 10:05:34 -0800637 depends on SYSFS
Kay Sieversf6ee6492009-04-16 19:56:37 +0200638 default n
Ingo Molnard47846c2008-03-04 14:54:47 +0100639 select SYSFS_DEPRECATED
Kay Sievers88a22c92006-09-14 11:23:28 +0200640 help
Kay Sieversfce3e802008-11-01 14:03:00 +0100641 This option switches the layout of sysfs to the deprecated
Kay Sieversf6ee6492009-04-16 19:56:37 +0200642 version. Do not use it on recent distributions.
Kay Sievers88a22c92006-09-14 11:23:28 +0200643
Kay Sieversfce3e802008-11-01 14:03:00 +0100644 The current sysfs layout features a unified device tree at
645 /sys/devices/, which is able to express a hierarchy between
646 class devices. If the deprecated option is set to Y, the
647 unified device tree is split into a bus device tree at
648 /sys/devices/ and several individual class device trees at
649 /sys/class/. The class and bus devices will be connected by
650 "<subsystem>:<name>" and the "device" links. The "block"
651 class devices, will not show up in /sys/class/block/. Some
652 subsystems will suppress the creation of some devices which
653 depend on the unified device tree.
Kay Sievers88a22c92006-09-14 11:23:28 +0200654
Kay Sieversfce3e802008-11-01 14:03:00 +0100655 This option is not a pure compatibility option that can
656 be safely enabled on newer distributions. It will change the
657 layout of sysfs to the non-extensible deprecated version,
658 and disable some features, which can not be exported without
659 confusing older userspace tools. Since 2007/2008 all major
660 distributions do not enable this option, and ship no tools which
661 depend on the deprecated layout or this option.
662
663 If you are using a new kernel on an older distribution, or use
664 older userspace tools, you might need to say Y here. Do not say Y,
665 if the original kernel, that came with your distribution, has
666 this option set to N.
Kay Sievers88a22c92006-09-14 11:23:28 +0200667
Jens Axboeb86ff9812006-03-23 19:56:55 +0100668config RELAY
669 bool "Kernel->user space relay support (formerly relayfs)"
670 help
671 This option enables support for relay interface support in
672 certain file systems (such as debugfs).
673 It is designed to provide an efficient mechanism for tools and
674 facilities to relay large amounts of data from kernel space to
675 user space.
676
677 If unsure, say N.
678
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800679config NAMESPACES
680 bool "Namespaces support" if EMBEDDED
681 default !EMBEDDED
682 help
683 Provides the way to make tasks work with different objects using
684 the same id. For example same IPC id may refer to different objects
685 or same user id or pid may refer to different tasks when used in
686 different namespaces.
687
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800688config UTS_NS
689 bool "UTS namespace"
690 depends on NAMESPACES
691 help
692 In this namespace tasks see different info provided with the
693 uname() system call
694
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800695config IPC_NS
696 bool "IPC namespace"
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700697 depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800698 help
699 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700700 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800701
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800702config USER_NS
703 bool "User namespace (EXPERIMENTAL)"
704 depends on NAMESPACES && EXPERIMENTAL
705 help
706 This allows containers, i.e. vservers, to use user namespaces
707 to provide different user info for different servers.
708 If unsure, say N.
709
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800710config PID_NS
711 bool "PID Namespaces (EXPERIMENTAL)"
712 default n
713 depends on NAMESPACES && EXPERIMENTAL
714 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300715 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100716 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800717 pid namespaces. This is a building block of containers.
718
719 Unless you want to work with an experimental feature
720 say N here.
721
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800722config NET_NS
723 bool "Network namespace"
724 default n
725 depends on NAMESPACES && EXPERIMENTAL && NET
726 help
727 Allow user space to create what appear to be multiple instances
728 of the network stack.
729
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800730config BLK_DEV_INITRD
731 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
732 depends on BROKEN || !FRV
733 help
734 The initial RAM filesystem is a ramfs which is loaded by the
735 boot loader (loadlin or lilo) and that is mounted as root
736 before the normal boot procedure. It is typically used to
737 load modules needed to mount the "real" root file system,
738 etc. See <file:Documentation/initrd.txt> for details.
739
740 If RAM disk support (BLK_DEV_RAM) is also included, this
741 also enables initial RAM disk (initrd) support and adds
742 15 Kbytes (more on some other architectures) to the kernel size.
743
744 If unsure say Y.
745
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800746if BLK_DEV_INITRD
747
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200748source "usr/Kconfig"
749
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800750endif
751
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800752config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200753 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800754 default y
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800755 help
756 Enabling this option will pass "-Os" instead of "-O2" to gcc
757 resulting in a smaller kernel.
758
jkacur775a7222008-07-16 00:31:16 +0200759 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800760
Randy Dunlap08470622006-09-30 23:28:13 -0700761config SYSCTL
762 bool
763
Randy Dunlapb943c462009-03-10 12:55:46 -0700764config ANON_INODES
765 bool
766
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767menuconfig EMBEDDED
768 bool "Configure standard kernel features (for small systems)"
769 help
770 This option allows certain base kernel options and settings
771 to be disabled or tweaked. This is for specialized
772 environments which can tolerate a "non-standard" kernel.
773 Only use this if you really know what you are doing.
774
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700775config UID16
776 bool "Enable 16-bit UID system calls" if EMBEDDED
David S. Miller09337f52008-04-26 03:17:12 -0700777 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 -0700778 default y
779 help
780 This enables the legacy 16-bit UID syscall wrappers.
781
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700782config SYSCTL_SYSCALL
Randy Dunlap08470622006-09-30 23:28:13 -0700783 bool "Sysctl syscall support" if EMBEDDED
Eric W. Biederman26a70342009-11-05 05:26:41 -0800784 depends on PROC_SYSCTL
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800785 default y
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700786 select SYSCTL
787 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800788 sys_sysctl uses binary paths that have been found challenging
789 to properly maintain and use. The interface in /proc/sys
790 using paths with ascii names is now the primary path to this
791 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700792
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800793 Almost nothing using the binary sysctl interface so if you are
794 trying to save some space it is probably safe to disable this,
795 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700796
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800797 If unsure say Y here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799config KALLSYMS
Jesper Juhl979c6a12006-12-12 19:25:11 +0100800 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 default y
802 help
803 Say Y here to let the kernel print out symbolic crash information and
804 symbolic stack backtraces. This increases the size of the kernel
805 somewhat, as all symbols have to be loaded into the kernel image.
806
807config KALLSYMS_ALL
808 bool "Include all symbols in kallsyms"
809 depends on DEBUG_KERNEL && KALLSYMS
810 help
811 Normally kallsyms only contains the symbols of functions, for nicer
812 OOPS messages. Some debuggers can use kallsyms for other
Jesper Juhlf9f97bc2005-07-20 05:43:05 +0200813 symbols too: say Y here to include all symbols, if you need them
814 and you don't care about adding 300k to the size of your kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815
816 Say N.
817
818config KALLSYMS_EXTRA_PASS
819 bool "Do an extra kallsyms pass"
820 depends on KALLSYMS
821 help
822 If kallsyms is not working correctly, the build will fail with
823 inconsistent kallsyms data. If that occurs, log a bug report and
824 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
825 Always say N here unless you find a bug in kallsyms, which must be
826 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
827 you wait for kallsyms to be fixed.
828
Matt Mackalld59745c2005-05-01 08:59:02 -0700829
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -0800830config HOTPLUG
831 bool "Support for hot-pluggable devices" if EMBEDDED
832 default y
833 help
834 This option is provided for the case where no hotplug or uevent
835 capabilities is wanted by the kernel. You should only consider
836 disabling this option for embedded systems that do not use modules, a
837 dynamic /dev tree, or dynamic device discovery. Just say Y.
838
Matt Mackalld59745c2005-05-01 08:59:02 -0700839config PRINTK
840 default y
841 bool "Enable support for printk" if EMBEDDED
842 help
843 This option enables normal printk support. Removing it
844 eliminates most of the message strings from the kernel image
845 and makes the kernel more or less silent. As this makes it
846 very difficult to diagnose system problems, saying N here is
847 strongly discouraged.
848
Matt Mackallc8538a72005-05-01 08:59:01 -0700849config BUG
850 bool "BUG() support" if EMBEDDED
851 default y
852 help
853 Disabling this option eliminates support for BUG and WARN, reducing
854 the size of your kernel image and potentially quietly ignoring
855 numerous fatal conditions. You should only consider disabling this
856 option for embedded systems with no facilities for reporting errors.
857 Just say Y.
858
Matt Mackall708e9a72006-01-08 01:05:25 -0800859config ELF_CORE
860 default y
861 bool "Enable ELF core dumps" if EMBEDDED
862 help
863 Enable support for generating core dumps. Disabling saves about 4k.
864
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +0200865config PCSPKR_PLATFORM
866 bool "Enable PC-Speaker support" if EMBEDDED
867 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
868 default y
869 help
870 This option allows to disable the internal PC-Speaker
871 support, saving some memory.
872
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873config BASE_FULL
874 default y
875 bool "Enable full-sized data structures for core" if EMBEDDED
876 help
877 Disabling this option reduces the size of miscellaneous core
878 kernel data structures. This saves memory on small machines,
879 but may reduce performance.
880
881config FUTEX
882 bool "Enable futex support" if EMBEDDED
883 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -0700884 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 help
886 Disabling this option will cause the kernel to be built without
887 support for "fast userspace mutexes". The resulting kernel may not
888 run glibc-based applications correctly.
889
890config EPOLL
891 bool "Enable eventpoll support" if EMBEDDED
892 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700893 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 help
895 Disabling this option will cause the kernel to be built without
896 support for epoll family of system calls.
897
Davide Libenzifba2afa2007-05-10 22:23:13 -0700898config SIGNALFD
899 bool "Enable signalfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700900 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -0700901 default y
902 help
903 Enable the signalfd() system call that allows to receive signals
904 on a file descriptor.
905
906 If unsure, say Y.
907
Davide Libenzib215e282007-05-10 22:23:16 -0700908config TIMERFD
909 bool "Enable timerfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700910 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -0700911 default y
912 help
913 Enable the timerfd() system call that allows to receive timer
914 events on a file descriptor.
915
916 If unsure, say Y.
917
Davide Libenzie1ad7462007-05-10 22:23:19 -0700918config EVENTFD
919 bool "Enable eventfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700920 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -0700921 default y
922 help
923 Enable the eventfd() system call that allows to receive both
924 kernel notification (ie. KAIO) or userspace notifications.
925
926 If unsure, say Y.
927
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928config SHMEM
929 bool "Use full shmem filesystem" if EMBEDDED
930 default y
931 depends on MMU
932 help
933 The shmem is an internal filesystem used to manage shared memory.
934 It is backed by swap and manages resource limits. It is also exported
935 to userspace as tmpfs if TMPFS is enabled. Disabling this
936 option replaces shmem and tmpfs with the much simpler ramfs code,
937 which may be appropriate on small systems without swap.
938
Thomas Petazzoniebf3f092008-10-15 22:05:12 -0700939config AIO
940 bool "Enable AIO support" if EMBEDDED
941 default y
942 help
943 This option enables POSIX asynchronous I/O which may by used
944 by some high performance threaded applications. Disabling
945 this option saves about 7k.
946
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200947config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +0100948 bool
Mike Frysinger018df722009-06-12 13:17:43 -0400949 help
950 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100951
Peter Zijlstra906010b2009-09-21 16:08:49 +0200952config PERF_USE_VMALLOC
953 bool
954 help
955 See tools/perf/design.txt for details
956
Ingo Molnar57c0c152009-09-21 12:20:38 +0200957menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +0100958
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200959config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +0200960 bool "Kernel performance events and counters"
961 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200962 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +0100963 select ANON_INODES
Thomas Gleixner0793a612008-12-04 20:12:29 +0100964 help
Ingo Molnar57c0c152009-09-21 12:20:38 +0200965 Enable kernel support for various performance events provided
966 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100967
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -0200968 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +0200969 use of generic tracepoints.
970
971 Most modern CPUs support performance events via performance
972 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +0100973 types of hw events: such as instructions executed, cachemisses
974 suffered, or branches mis-predicted - without slowing down the
975 kernel or applications. These registers can also trigger interrupts
976 when a threshold number of events have passed - and can thus be
977 used to profile the code that runs on that CPU.
978
Ingo Molnar57c0c152009-09-21 12:20:38 +0200979 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -0200980 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +0200981 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +0100982 provides per task and per CPU counters, and it provides event
983 capabilities on top of those.
984
985 Say Y if unsure.
986
Peter Zijlstrae077df42009-03-19 20:26:17 +0100987config EVENT_PROFILE
Peter Zijlstra470a1392009-07-29 10:50:09 +0200988 bool "Tracepoint profiling sources"
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200989 depends on PERF_EVENTS && EVENT_TRACING
Peter Zijlstrae077df42009-03-19 20:26:17 +0100990 default y
Peter Zijlstra470a1392009-07-29 10:50:09 +0200991 help
Ingo Molnar57c0c152009-09-21 12:20:38 +0200992 Allow the use of tracepoints as software performance events.
Peter Zijlstra470a1392009-07-29 10:50:09 +0200993
Ingo Molnar57c0c152009-09-21 12:20:38 +0200994 When this is enabled, you can create perf events based on
Peter Zijlstra470a1392009-07-29 10:50:09 +0200995 tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID
996 found in debugfs://tracing/events/*/*/id. (The -e/--events
997 option to the perf tool can parse and interpret symbolic
998 tracepoints, in the subsystem:tracepoint_name format.)
Peter Zijlstrae077df42009-03-19 20:26:17 +0100999
Ingo Molnar57c0c152009-09-21 12:20:38 +02001000config PERF_COUNTERS
1001 bool "Kernel performance counters (old config option)"
1002 depends on HAVE_PERF_EVENTS
1003 help
1004 This config has been obsoleted by the PERF_EVENTS
1005 config option - please see that one for details.
1006
1007 It has no effect on the kernel whether you enable
1008 it or not, it is a compatibility placeholder.
1009
1010 Say N if unsure.
1011
Peter Zijlstra906010b2009-09-21 16:08:49 +02001012config DEBUG_PERF_USE_VMALLOC
1013 default n
1014 bool "Debug: use vmalloc to back perf mmap() buffers"
1015 depends on PERF_EVENTS && DEBUG_KERNEL
1016 select PERF_USE_VMALLOC
1017 help
1018 Use vmalloc memory to back perf mmap() buffers.
1019
1020 Mostly useful for debugging the vmalloc code on platforms
1021 that don't require it.
1022
1023 Say N if unsure.
1024
Thomas Gleixner0793a612008-12-04 20:12:29 +01001025endmenu
1026
Christoph Lameterf8891e52006-06-30 01:55:45 -07001027config VM_EVENT_COUNTERS
1028 default y
1029 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1030 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001031 VM event counters are needed for event counts to be shown.
1032 This option allows the disabling of the VM event counters
1033 on EMBEDDED systems. /proc/vmstat will only show page counts
1034 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001035
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001036config PCI_QUIRKS
1037 default y
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001038 bool "Enable PCI quirk workarounds" if EMBEDDED
1039 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001040 help
1041 This enables workarounds for various PCI chipset
1042 bugs/quirks. Disable this only if your target machine is
1043 unaffected by PCI quirks.
1044
Christoph Lameter41ecc552007-05-09 02:32:44 -07001045config SLUB_DEBUG
1046 default y
1047 bool "Enable SLUB debugging support" if EMBEDDED
Christoph Lameterf6acb632008-04-29 16:16:06 -07001048 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001049 help
1050 SLUB has extensive debug support features. Disabling these can
1051 result in significant savings in code size. This also disables
1052 SLUB sysfs support. /sys/slab will not exist and there will be
1053 no support for cache validation etc.
1054
Randy Dunlapb943c462009-03-10 12:55:46 -07001055config COMPAT_BRK
1056 bool "Disable heap randomization"
1057 default y
1058 help
1059 Randomizing heap placement makes heap exploits harder, but it
1060 also breaks ancient binaries (including anything libc5 based).
1061 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001062 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001063 /proc/sys/kernel/randomize_va_space to 2.
1064
1065 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1066
Christoph Lameter81819f02007-05-06 14:49:36 -07001067choice
1068 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001069 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001070 help
1071 This option allows to select a slab allocator.
1072
1073config SLAB
1074 bool "SLAB"
1075 help
1076 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001077 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001078 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001079
1080config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001081 bool "SLUB (Unqueued Allocator)"
1082 help
1083 SLUB is a slab allocator that minimizes cache line usage
1084 instead of managing queues of cached objects (SLAB approach).
1085 Per cpu caching is realized using slabs of objects instead
1086 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001087 and has enhanced diagnostics. SLUB is the default choice for
1088 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001089
1090config SLOB
Paul Mundt84a01c22007-07-15 23:38:24 -07001091 depends on EMBEDDED
Christoph Lameter81819f02007-05-06 14:49:36 -07001092 bool "SLOB (Simple Allocator)"
1093 help
Matt Mackall37291452008-02-04 22:29:38 -08001094 SLOB replaces the stock allocator with a drastically simpler
1095 allocator. SLOB is generally more space efficient but
1096 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001097
1098endchoice
1099
Jie Zhangea637632009-12-14 18:00:02 -08001100config MMAP_ALLOW_UNINITIALIZED
1101 bool "Allow mmapped anonymous memory to be uninitialized"
1102 depends on EMBEDDED && !MMU
1103 default n
1104 help
1105 Normally, and according to the Linux spec, anonymous memory obtained
1106 from mmap() has it's contents cleared before it is passed to
1107 userspace. Enabling this config option allows you to request that
1108 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1109 providing a huge performance boost. If this option is not enabled,
1110 then the flag will be ignored.
1111
1112 This is taken advantage of by uClibc's malloc(), and also by
1113 ELF-FDPIC binfmt's brk and stack allocator.
1114
1115 Because of the obvious security issues, this option should only be
1116 enabled on embedded devices where you control what is run in
1117 userspace. Since that isn't generally a problem on no-MMU systems,
1118 it is normally safe to say Y here.
1119
1120 See Documentation/nommu-mmap.txt for more information.
1121
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001122config PROFILING
1123 bool "Profiling support (EXPERIMENTAL)"
1124 help
1125 Say Y here to enable the extended profiling support mechanisms used
1126 by profilers such as OProfile.
1127
Ingo Molnar5f87f112008-07-23 14:15:22 +02001128#
1129# Place an empty function call at each tracepoint site. Can be
1130# dynamically changed for a probe function.
1131#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001132config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001133 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001134
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001135source "arch/Kconfig"
1136
David Howells07fe7cb2009-04-03 16:42:35 +01001137config SLOW_WORK
1138 default n
David Howells1c2d0082009-04-06 15:47:25 +01001139 bool
David Howells07fe7cb2009-04-03 16:42:35 +01001140 help
1141 The slow work thread pool provides a number of dynamically allocated
1142 threads that can be used by the kernel to perform operations that
1143 take a relatively long time.
1144
1145 An example of this would be CacheFiles doing a path lookup followed
1146 by a series of mkdirs and a create call, all of which have to touch
1147 disk.
1148
David Howells1c2d0082009-04-06 15:47:25 +01001149 See Documentation/slow-work.txt.
1150
David Howellsf13a48b2009-12-01 15:36:11 +00001151config SLOW_WORK_DEBUG
1152 bool "Slow work debugging through debugfs"
David Howells8fba10a2009-11-19 18:10:51 +00001153 default n
David Howellsf13a48b2009-12-01 15:36:11 +00001154 depends on SLOW_WORK && DEBUG_FS
David Howells8fba10a2009-11-19 18:10:51 +00001155 help
David Howellsf13a48b2009-12-01 15:36:11 +00001156 Display the contents of the slow work run queue through debugfs,
David Howells8fba10a2009-11-19 18:10:51 +00001157 including items currently executing.
1158
1159 See Documentation/slow-work.txt.
1160
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161endmenu # General setup
1162
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001163config HAVE_GENERIC_DMA_COHERENT
1164 bool
1165 default n
1166
Linus Torvalds158a9622008-01-02 13:04:48 -08001167config SLABINFO
1168 bool
1169 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001170 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001171 default y
1172
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001173config RT_MUTEXES
1174 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001175
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176config BASE_SMALL
1177 int
1178 default 0 if BASE_FULL
1179 default 1 if !BASE_FULL
1180
Jan Engelhardt66da5732007-07-15 23:39:29 -07001181menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 bool "Enable loadable module support"
1183 help
1184 Kernel modules are small pieces of compiled code which can
1185 be inserted in the running kernel, rather than being
1186 permanently built into the kernel. You use the "modprobe"
1187 tool to add (and sometimes remove) them. If you say Y here,
1188 many parts of the kernel can be built as modules (by
1189 answering M instead of Y where indicated): this is most
1190 useful for infrequently used options which are not required
1191 for booting. For more information, see the man pages for
1192 modprobe, lsmod, modinfo, insmod and rmmod.
1193
1194 If you say Y here, you will need to run "make
1195 modules_install" to put the modules under /lib/modules/
1196 where modprobe can find them (you may need to be root to do
1197 this).
1198
1199 If unsure, say Y.
1200
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001201if MODULES
1202
Linus Torvalds826e4502008-05-04 17:04:16 -07001203config MODULE_FORCE_LOAD
1204 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001205 default n
1206 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001207 Allow loading of modules without version information (ie. modprobe
1208 --force). Forced module loading sets the 'F' (forced) taint flag and
1209 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001210
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211config MODULE_UNLOAD
1212 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 help
1214 Without this option you will not be able to unload any
1215 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001216 anyway), which makes your kernel smaller, faster
1217 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218
1219config MODULE_FORCE_UNLOAD
1220 bool "Forced module unloading"
1221 depends on MODULE_UNLOAD && EXPERIMENTAL
1222 help
1223 This option allows you to force a module to unload, even if the
1224 kernel believes it is unsafe: the kernel will remove the module
1225 without waiting for anyone to stop using it (using the -f option to
1226 rmmod). This is mainly for kernel developers and desperate users.
1227 If unsure, say N.
1228
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001230 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 help
1232 Usually, you have to use modules compiled with your kernel.
1233 Saying Y here makes it sometimes possible to use modules
1234 compiled for different kernels, by adding enough information
1235 to the modules to (hopefully) spot any changes which would
1236 make them incompatible with the kernel you are running. If
1237 unsure, say N.
1238
1239config MODULE_SRCVERSION_ALL
1240 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 help
1242 Modules which contain a MODULE_VERSION get an extra "srcversion"
1243 field inserted into their modinfo section, which contains a
1244 sum of the source files which made it. This helps maintainers
1245 see exactly which source was used to build a module (since
1246 others sometimes change the module source without updating
1247 the version). With this option, such a "srcversion" field
1248 will be created for all modules. If unsure, say N.
1249
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001250endif # MODULES
1251
Rusty Russell98a79d62008-12-13 21:19:41 +10301252config INIT_ALL_POSSIBLE
1253 bool
1254 help
1255 Back when each arch used to define their own cpu_online_map and
1256 cpu_possible_map, some of them chose to initialize cpu_possible_map
1257 with all 1s, and others with all 0s. When they were centralised,
1258 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001259 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301260
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261config STOP_MACHINE
1262 bool
1263 default y
1264 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1265 help
1266 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001267
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001268source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001269
1270config PREEMPT_NOTIFIERS
1271 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001272
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001273source "kernel/Kconfig.locks"