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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
Peter Zijlstrae360adb2010-10-14 14:01:34 +080024config HAVE_IRQ_WORK
25 bool
26
27config IRQ_WORK
28 bool
29 depends on HAVE_IRQ_WORK
30
Al Boldiff0cfc62007-07-31 00:39:23 -070031menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33config EXPERIMENTAL
34 bool "Prompt for development and/or incomplete code/drivers"
35 ---help---
36 Some of the various things that Linux supports (such as network
37 drivers, file systems, network protocols, etc.) can be in a state
38 of development where the functionality, stability, or the level of
39 testing is not yet high enough for general use. This is usually
40 known as the "alpha-test" phase among developers. If a feature is
41 currently in alpha-test, then the developers usually discourage
42 uninformed widespread use of this feature by the general public to
43 avoid "Why doesn't this work?" type mail messages. However, active
44 testing and use of these systems is welcomed. Just be aware that it
45 may not meet the normal level of reliability or it may fail to work
46 in some special cases. Detailed bug reports from people familiar
47 with the kernel internals are usually welcomed by the developers
48 (before submitting bug reports, please read the documents
49 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
50 <file:Documentation/BUG-HUNTING>, and
51 <file:Documentation/oops-tracing.txt> in the kernel source).
52
53 This option will also make obsoleted drivers available. These are
54 drivers that have been replaced by something else, and/or are
55 scheduled to be removed in a future kernel release.
56
57 Unless you intend to help test and develop a feature or driver that
58 falls into this category, or you have a situation that requires
59 using these features, you should probably say N here, which will
60 cause the configurator to present you with fewer choices. If
61 you say Y here, you will be offered the choice of using features or
62 drivers that are currently considered to be in the alpha-test phase.
63
Linus Torvalds1da177e2005-04-16 15:20:36 -070064config BROKEN
65 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67config BROKEN_ON_SMP
68 bool
69 depends on BROKEN || !SMP
70 default y
71
72config LOCK_KERNEL
73 bool
Arnd Bergmann6de5bd12010-09-11 18:00:57 +020074 depends on (SMP || PREEMPT) && BKL
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 default y
76
77config INIT_ENV_ARG_LIMIT
78 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070079 default 32 if !UML
80 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080082 Maximum of each of the number of arguments and environment
83 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Roland McGrath84336462009-12-21 16:24:06 -080086config CROSS_COMPILE
87 string "Cross-compiler tool prefix"
88 help
89 Same as running 'make CROSS_COMPILE=prefix-' but stored for
90 default make runs in this kernel build directory. You don't
91 need to set this unless you want the configured kernel build
92 directory to select the cross-compiler automatically.
93
Linus Torvalds1da177e2005-04-16 15:20:36 -070094config LOCALVERSION
95 string "Local version - append to kernel release"
96 help
97 Append an extra string to the end of your kernel version.
98 This will show up when you type uname, for example.
99 The string you set here will be appended after the contents of
100 any files with a filename matching localversion* in your
101 object and source tree, in that order. Your total string can
102 be a maximum of 64 characters.
103
Ryan Andersonaaebf432005-07-31 04:57:49 -0400104config LOCALVERSION_AUTO
105 bool "Automatically append version information to the version string"
106 default y
107 help
108 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200109 release tree by looking for git tags that belong to the current
110 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400111
112 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200113 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400114 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200115 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400116
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200117 (The actual string used here is the first eight characters produced
118 by running the command:
119
120 $ git rev-parse --verify HEAD
121
122 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400123
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800124config HAVE_KERNEL_GZIP
125 bool
126
127config HAVE_KERNEL_BZIP2
128 bool
129
130config HAVE_KERNEL_LZMA
131 bool
132
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800133config HAVE_KERNEL_LZO
134 bool
135
Alain Knaff30d65db2009-01-04 22:46:17 +0100136choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800137 prompt "Kernel compression mode"
138 default KERNEL_GZIP
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800139 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800140 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100141 The linux kernel is a kind of self-extracting executable.
142 Several compression algorithms are available, which differ
143 in efficiency, compression and decompression speed.
144 Compression speed is only relevant when building a kernel.
145 Decompression speed is relevant at each boot.
146
147 If you have any problems with bzip2 or lzma compressed
148 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
149 version of this functionality (bzip2 only), for 2.4, was
150 supplied by Christian Ludwig)
151
152 High compression options are mostly useful for users, who
153 are low on disk space (embedded systems), but for whom ram
154 size matters less.
155
156 If in doubt, select 'gzip'
157
158config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800159 bool "Gzip"
160 depends on HAVE_KERNEL_GZIP
161 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800162 The old and tried gzip compression. It provides a good balance
163 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
165config KERNEL_BZIP2
166 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800167 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100168 help
169 Its compression ratio and speed is intermediate.
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800170 Decompression speed is slowest among the three. The kernel
171 size is about 10% smaller with bzip2, in comparison to gzip.
172 Bzip2 uses a large amount of memory. For modern kernels you
173 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100174
175config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800176 bool "LZMA"
177 depends on HAVE_KERNEL_LZMA
178 help
179 The most recent compression algorithm.
180 Its ratio is best, decompression speed is between the other
181 two. Compression is slowest. The kernel size is about 33%
182 smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100183
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800184config KERNEL_LZO
185 bool "LZO"
186 depends on HAVE_KERNEL_LZO
187 help
188 Its compression ratio is the poorest among the 4. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200189 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800190 (both compression and decompression) is the fastest.
191
Alain Knaff30d65db2009-01-04 22:46:17 +0100192endchoice
193
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194config SWAP
195 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200196 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 default y
198 help
199 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100200 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 used to provide more virtual memory than the actual RAM present
202 in your computer. If unsure say Y.
203
204config SYSVIPC
205 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 ---help---
207 Inter Process Communication is a suite of library functions and
208 system calls which let processes (running programs) synchronize and
209 exchange information. It is generally considered to be a good thing,
210 and some programs won't run unless you say Y here. In particular, if
211 you want to run the DOS emulator dosemu under Linux (read the
212 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
213 you'll need to say Y here.
214
215 You can find documentation about IPC with "info ipc" and also in
216 section 6.4 of the Linux Programmer's Guide, available from
217 <http://www.tldp.org/guides.html>.
218
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800219config SYSVIPC_SYSCTL
220 bool
221 depends on SYSVIPC
222 depends on SYSCTL
223 default y
224
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225config POSIX_MQUEUE
226 bool "POSIX Message Queues"
227 depends on NET && EXPERIMENTAL
228 ---help---
229 POSIX variant of message queues is a part of IPC. In POSIX message
230 queues every message has a priority which decides about succession
231 of receiving it by a process. If you want to compile and run
232 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200233 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
235 POSIX message queues are visible as a filesystem called 'mqueue'
236 and can be mounted somewhere if you want to do filesystem
237 operations on message queues.
238
239 If unsure, say Y.
240
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700241config POSIX_MQUEUE_SYSCTL
242 bool
243 depends on POSIX_MQUEUE
244 depends on SYSCTL
245 default y
246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247config BSD_PROCESS_ACCT
248 bool "BSD Process Accounting"
249 help
250 If you say Y here, a user level program will be able to instruct the
251 kernel (via a special system call) to write process accounting
252 information to a file: whenever a process exits, information about
253 that process will be appended to the file by the kernel. The
254 information includes things such as creation time, owning user,
255 command name, memory usage, controlling terminal etc. (the complete
256 list is in the struct acct in <file:include/linux/acct.h>). It is
257 up to the user level program to do useful things with this
258 information. This is generally a good idea, so say Y.
259
260config BSD_PROCESS_ACCT_V3
261 bool "BSD Process Accounting version 3 file format"
262 depends on BSD_PROCESS_ACCT
263 default n
264 help
265 If you say Y here, the process accounting information is written
266 in a new file format that also logs the process IDs of each
267 process and it's parent. Note that this file format is incompatible
268 with previous v0/v1/v2 file formats, so you will need updated tools
269 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300270 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
Shailabh Nagarc7572492006-07-14 00:24:40 -0700272config TASKSTATS
273 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
274 depends on NET
275 default n
276 help
277 Export selected statistics for tasks/processes through the
278 generic netlink interface. Unlike BSD process accounting, the
279 statistics are available during the lifetime of tasks/processes as
280 responses to commands. Like BSD accounting, they are sent to user
281 space on task exit.
282
283 Say N if unsure.
284
Shailabh Nagarca74e922006-07-14 00:24:36 -0700285config TASK_DELAY_ACCT
286 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700287 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700288 help
289 Collect information on time spent by a task waiting for system
290 resources like cpu, synchronous block I/O completion and swapping
291 in pages. Such statistics can help in setting a task's priorities
292 relative to other tasks for cpu, io, rss limits etc.
293
294 Say N if unsure.
295
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800296config TASK_XACCT
297 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
298 depends on TASKSTATS
299 help
300 Collect extended task accounting data and send the data
301 to userland for processing over the taskstats interface.
302
303 Say N if unsure.
304
305config TASK_IO_ACCOUNTING
306 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
307 depends on TASK_XACCT
308 help
309 Collect information on the number of bytes of storage I/O which this
310 task has caused.
311
312 Say N if unsure.
313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314config AUDIT
315 bool "Auditing support"
Chris Wright804a6a42005-05-11 10:52:45 +0100316 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 help
318 Enable auditing infrastructure that can be used with another
319 kernel subsystem, such as SELinux (which requires this for
320 logging of avc messages output). Does not do system-call
321 auditing without CONFIG_AUDITSYSCALL.
322
323config AUDITSYSCALL
324 bool "Enable system-call auditing support"
Kumar Gala022382a2009-10-16 07:21:37 +0000325 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 default y if SECURITY_SELINUX
327 help
328 Enable low-overhead system-call auditing infrastructure that
329 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500330 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
Eric Paris939a67f2009-12-17 20:12:06 -0500332config AUDIT_WATCH
333 def_bool y
334 depends on AUDITSYSCALL
335 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336
Al Viro74c3cbe2007-07-22 08:04:18 -0400337config AUDIT_TREE
338 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400339 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500340 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400341
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000342source "kernel/irq/Kconfig"
343
Mike Travisc903ff82009-01-15 12:28:29 -0800344menu "RCU Subsystem"
345
346choice
347 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700348 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800349
Mike Travisc903ff82009-01-15 12:28:29 -0800350config TREE_RCU
351 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700352 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800353 help
354 This option selects the RCU implementation that is
355 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700356 thousands of CPUs. It also scales down nicely to
357 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800358
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700359config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700360 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700361 depends on PREEMPT
362 help
363 This option selects the RCU implementation that is
364 designed for very large SMP systems with hundreds or
365 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700366 is also required. It also scales down nicely to
367 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700368
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700369config TINY_RCU
370 bool "UP-only small-memory-footprint RCU"
371 depends on !SMP
372 help
373 This option selects the RCU implementation that is
374 designed for UP systems from which real-time response
375 is not required. This option greatly reduces the
376 memory footprint of RCU.
377
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700378config TINY_PREEMPT_RCU
379 bool "Preemptible UP-only small-memory-footprint RCU"
380 depends on !SMP && PREEMPT
381 help
382 This option selects the RCU implementation that is designed
383 for real-time UP systems. This option greatly reduces the
384 memory footprint of RCU.
385
Mike Travisc903ff82009-01-15 12:28:29 -0800386endchoice
387
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700388config PREEMPT_RCU
389 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
390 help
391 This option enables preemptible-RCU code that is common between
392 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
393
Mike Travisc903ff82009-01-15 12:28:29 -0800394config RCU_TRACE
395 bool "Enable tracing for RCU"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700396 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800397 help
398 This option provides tracing in RCU which presents stats
399 in debugfs for debugging RCU implementation.
400
401 Say Y here if you want to enable RCU tracing
402 Say N if you are unsure.
403
404config RCU_FANOUT
405 int "Tree-based hierarchical RCU fanout value"
406 range 2 64 if 64BIT
407 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700408 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800409 default 64 if 64BIT
410 default 32 if !64BIT
411 help
412 This option controls the fanout of hierarchical implementations
413 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700414 large numbers of CPUs. This value must be at least the fourth
415 root of NR_CPUS, which allows NR_CPUS to be insanely large.
416 The default value of RCU_FANOUT should be used for production
417 systems, but if you are stress-testing the RCU implementation
418 itself, small RCU_FANOUT values allow you to test large-system
419 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800420
421 Select a specific number if testing RCU itself.
422 Take the default if unsure.
423
424config RCU_FANOUT_EXACT
425 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700426 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800427 default n
428 help
429 This option forces use of the exact RCU_FANOUT value specified,
430 regardless of imbalances in the hierarchy. This is useful for
431 testing RCU itself, and might one day be useful on systems with
432 strong NUMA behavior.
433
434 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
435
436 Say N if unsure.
437
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800438config RCU_FAST_NO_HZ
439 bool "Accelerate last non-dyntick-idle CPU's grace periods"
440 depends on TREE_RCU && NO_HZ && SMP
441 default n
442 help
443 This option causes RCU to attempt to accelerate grace periods
444 in order to allow the final CPU to enter dynticks-idle state
445 more quickly. On the other hand, this option increases the
446 overhead of the dynticks-idle checking, particularly on systems
447 with large numbers of CPUs.
448
449 Say Y if energy efficiency is critically important, particularly
450 if you have relatively few CPUs.
451
452 Say N if you are unsure.
453
Mike Travisc903ff82009-01-15 12:28:29 -0800454config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700455 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800456 select DEBUG_FS
457 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700458 This option provides tracing for the TREE_RCU and
459 TREE_PREEMPT_RCU implementations, permitting Makefile to
460 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800461
Mike Travisc903ff82009-01-15 12:28:29 -0800462endmenu # "RCU Subsystem"
463
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700465 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 ---help---
467 This option enables the complete Linux kernel ".config" file
468 contents to be saved in the kernel. It provides documentation
469 of which kernel options are used in a running kernel or in an
470 on-disk kernel. This information can be extracted from the kernel
471 image file with the script scripts/extract-ikconfig and used as
472 input to rebuild the current kernel or to build another kernel.
473 It can also be extracted from a running kernel by reading
474 /proc/config.gz if enabled (below).
475
476config IKCONFIG_PROC
477 bool "Enable access to .config through /proc/config.gz"
478 depends on IKCONFIG && PROC_FS
479 ---help---
480 This option enables access to the kernel configuration file
481 through /proc/config.gz.
482
Alistair John Strachan794543a2007-05-08 00:31:15 -0700483config LOG_BUF_SHIFT
484 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
485 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700486 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700487 help
488 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700489 Examples:
490 17 => 128 KB
491 16 => 64 KB
492 15 => 32 KB
493 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700494 13 => 8 KB
495 12 => 4 KB
496
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800497#
498# Architectures with an unreliable sched_clock() should select this:
499#
500config HAVE_UNSTABLE_SCHED_CLOCK
501 bool
502
Li Zefan23964d22009-01-15 13:50:58 -0800503menuconfig CGROUPS
504 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800505 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700506 help
Li Zefan23964d22009-01-15 13:50:58 -0800507 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800508 use with process control subsystems such as Cpusets, CFS, memory
509 controls or device isolation.
510 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800511 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800512 - Documentation/cgroups/ (features for grouping, isolation
513 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700514
515 Say N if unsure.
516
Li Zefan23964d22009-01-15 13:50:58 -0800517if CGROUPS
518
Paul Menage006cb992007-10-18 23:39:43 -0700519config CGROUP_DEBUG
520 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700521 default n
Paul Menage006cb992007-10-18 23:39:43 -0700522 help
523 This option enables a simple cgroup subsystem that
524 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800525 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700526
Li Zefan23964d22009-01-15 13:50:58 -0800527 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700528
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700529config CGROUP_NS
Li Zefan23964d22009-01-15 13:50:58 -0800530 bool "Namespace cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800531 help
532 Provides a simple namespace cgroup subsystem to
533 provide hierarchical naming of sets of namespaces,
534 for instance virtual servers and checkpoint/restart
535 jobs.
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700536
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700537config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800538 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800539 help
540 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700541 cgroup.
542
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700543config CGROUP_DEVICE
544 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700545 help
546 Provides a cgroup implementing whitelists for devices which
547 a process in the cgroup can mknod or open.
548
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549config CPUSETS
550 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700552 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 allow dynamically partitioning a system into sets of CPUs and
554 Memory Nodes and assigning tasks to run only within those sets.
555 This is primarily useful on large SMP or NUMA systems.
556
557 Say N if unsure.
558
Li Zefan23964d22009-01-15 13:50:58 -0800559config PROC_PID_CPUSET
560 bool "Include legacy /proc/<pid>/cpuset file"
561 depends on CPUSETS
562 default y
563
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100564config CGROUP_CPUACCT
565 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100566 help
567 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800568 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100569
Pavel Emelianove552b662008-02-07 00:13:49 -0800570config RESOURCE_COUNTERS
571 bool "Resource counters"
572 help
573 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800574 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800575
Balbir Singh00f0b822008-03-04 14:28:39 -0800576config CGROUP_MEM_RES_CTLR
577 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700578 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700579 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800580 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700581 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100582 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800583
584 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700585 associated with each page of memory in the system. By this,
586 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
587 usage tracking struct at boot. Total amount of this is printed out
588 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800589
590 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700591 sure you need the memory resource controller. Even when you enable
592 this, you can set "cgroup_disable=memory" at your boot option to
593 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800594 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800595
Balbir Singhcf475ad2008-04-29 01:00:16 -0700596 This config option also selects MM_OWNER config option, which
597 could in turn add some fork/exit overhead.
598
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800599config CGROUP_MEM_RES_CTLR_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700600 bool "Memory Resource Controller Swap Extension"
601 depends on CGROUP_MEM_RES_CTLR && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800602 help
603 Add swap management feature to memory resource controller. When you
604 enable this, you can limit mem+swap usage per cgroup. In other words,
605 when you disable this, memory resource controller has no cares to
606 usage of swap...a process can exhaust all of the swap. This extension
607 is useful when you want to avoid exhaustion swap but this itself
608 adds more overheads and consumes memory for remembering information.
609 Especially if you use 32bit system or small memory system, please
610 be careful about enabling this. When memory resource controller
611 is disabled by boot option, this will be automatically disabled and
612 there will be no overhead from this. Even when you set this config=y,
613 if boot option "noswapaccount" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700614 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
615 size is 4096bytes, 512k per 1Gbytes of swap.
Michal Hockoa42c3902010-11-24 12:57:08 -0800616config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
617 bool "Memory Resource Controller Swap Extension enabled by default"
618 depends on CGROUP_MEM_RES_CTLR_SWAP
619 default y
620 help
621 Memory Resource Controller Swap Extension comes with its price in
622 a bigger memory consumption. General purpose distribution kernels
623 which want to enable the feautre but keep it disabled by default
624 and let the user enable it by swapaccount boot command line
625 parameter should have this option unselected.
626 For those who want to have the feature enabled by default should
627 select this option (if, for some reason, they need to disable it
628 then noswapaccount does the trick).
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800629
Dhaval Giani7c941432010-01-20 13:26:18 +0100630menuconfig CGROUP_SCHED
631 bool "Group CPU scheduler"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700632 depends on EXPERIMENTAL
Dhaval Giani7c941432010-01-20 13:26:18 +0100633 default n
634 help
635 This feature lets CPU scheduler recognize task groups and control CPU
636 bandwidth allocation to such task groups. It uses cgroups to group
637 tasks.
638
639if CGROUP_SCHED
640config FAIR_GROUP_SCHED
641 bool "Group scheduling for SCHED_OTHER"
642 depends on CGROUP_SCHED
643 default CGROUP_SCHED
644
645config RT_GROUP_SCHED
646 bool "Group scheduling for SCHED_RR/FIFO"
647 depends on EXPERIMENTAL
648 depends on CGROUP_SCHED
649 default n
650 help
651 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800652 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100653 schedule realtime tasks for non-root users until you allocate
654 realtime bandwidth for them.
655 See Documentation/scheduler/sched-rt-group.txt for more information.
656
657endif #CGROUP_SCHED
658
Vivek Goyalafc24d42010-04-26 19:27:56 +0200659config BLK_CGROUP
660 tristate "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700661 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200662 default n
663 ---help---
664 Generic block IO controller cgroup interface. This is the common
665 cgroup interface which should be used by various IO controlling
666 policies.
667
668 Currently, CFQ IO scheduler uses it to recognize task groups and
669 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400670 to such task groups. It is also used by bio throttling logic in
671 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200672
673 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400674 One needs to also enable actual IO controlling logic/policy. For
675 enabling proportional weight division of disk bandwidth in CFQ seti
676 CONFIG_CFQ_GROUP_IOSCHED=y and for enabling throttling policy set
677 CONFIG_BLK_THROTTLE=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200678
679 See Documentation/cgroups/blkio-controller.txt for more information.
680
681config DEBUG_BLK_CGROUP
682 bool "Enable Block IO controller debugging"
683 depends on BLK_CGROUP
684 default n
685 ---help---
686 Enable some debugging help. Currently it exports additional stat
687 files in a cgroup which can be useful for debugging.
688
Li Zefan23964d22009-01-15 13:50:58 -0800689endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800690
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700691menuconfig NAMESPACES
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800692 bool "Namespaces support" if EMBEDDED
693 default !EMBEDDED
694 help
695 Provides the way to make tasks work with different objects using
696 the same id. For example same IPC id may refer to different objects
697 or same user id or pid may refer to different tasks when used in
698 different namespaces.
699
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700700if NAMESPACES
701
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800702config UTS_NS
703 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700704 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800705 help
706 In this namespace tasks see different info provided with the
707 uname() system call
708
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800709config IPC_NS
710 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700711 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700712 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800713 help
714 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700715 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800716
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800717config USER_NS
718 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700719 depends on EXPERIMENTAL
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700720 default y
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800721 help
722 This allows containers, i.e. vservers, to use user namespaces
723 to provide different user info for different servers.
724 If unsure, say N.
725
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800726config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700727 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700728 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800729 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300730 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100731 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800732 pid namespaces. This is a building block of containers.
733
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800734config NET_NS
735 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700736 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700737 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800738 help
739 Allow user space to create what appear to be multiple instances
740 of the network stack.
741
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700742endif # NAMESPACES
743
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700744config MM_OWNER
745 bool
746
747config SYSFS_DEPRECATED
748 bool "enable deprecated sysfs features to support old userspace tools"
749 depends on SYSFS
750 default n
751 help
752 This option adds code that switches the layout of the "block" class
753 devices, to not show up in /sys/class/block/, but only in
754 /sys/block/.
755
756 This switch is only active when the sysfs.deprecated=1 boot option is
757 passed or the SYSFS_DEPRECATED_V2 option is set.
758
759 This option allows new kernels to run on old distributions and tools,
760 which might get confused by /sys/class/block/. Since 2007/2008 all
761 major distributions and tools handle this just fine.
762
763 Recent distributions and userspace tools after 2009/2010 depend on
764 the existence of /sys/class/block/, and will not work with this
765 option enabled.
766
767 Only if you are using a new kernel on an old distribution, you might
768 need to say Y here.
769
770config SYSFS_DEPRECATED_V2
771 bool "enabled deprecated sysfs features by default"
772 default n
773 depends on SYSFS
774 depends on SYSFS_DEPRECATED
775 help
776 Enable deprecated sysfs by default.
777
778 See the CONFIG_SYSFS_DEPRECATED option for more details about this
779 option.
780
781 Only if you are using a new kernel on an old distribution, you might
782 need to say Y here. Even then, odds are you would not need it
783 enabled, you can always pass the boot option if absolutely necessary.
784
785config RELAY
786 bool "Kernel->user space relay support (formerly relayfs)"
787 help
788 This option enables support for relay interface support in
789 certain file systems (such as debugfs).
790 It is designed to provide an efficient mechanism for tools and
791 facilities to relay large amounts of data from kernel space to
792 user space.
793
794 If unsure, say N.
795
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800796config BLK_DEV_INITRD
797 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
798 depends on BROKEN || !FRV
799 help
800 The initial RAM filesystem is a ramfs which is loaded by the
801 boot loader (loadlin or lilo) and that is mounted as root
802 before the normal boot procedure. It is typically used to
803 load modules needed to mount the "real" root file system,
804 etc. See <file:Documentation/initrd.txt> for details.
805
806 If RAM disk support (BLK_DEV_RAM) is also included, this
807 also enables initial RAM disk (initrd) support and adds
808 15 Kbytes (more on some other architectures) to the kernel size.
809
810 If unsure say Y.
811
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800812if BLK_DEV_INITRD
813
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200814source "usr/Kconfig"
815
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800816endif
817
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800818config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200819 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800820 default y
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800821 help
822 Enabling this option will pass "-Os" instead of "-O2" to gcc
823 resulting in a smaller kernel.
824
jkacur775a7222008-07-16 00:31:16 +0200825 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800826
Randy Dunlap08470622006-09-30 23:28:13 -0700827config SYSCTL
828 bool
829
Randy Dunlapb943c462009-03-10 12:55:46 -0700830config ANON_INODES
831 bool
832
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833menuconfig EMBEDDED
834 bool "Configure standard kernel features (for small systems)"
835 help
836 This option allows certain base kernel options and settings
837 to be disabled or tweaked. This is for specialized
838 environments which can tolerate a "non-standard" kernel.
839 Only use this if you really know what you are doing.
840
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700841config UID16
842 bool "Enable 16-bit UID system calls" if EMBEDDED
David S. Miller09337f52008-04-26 03:17:12 -0700843 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 -0700844 default y
845 help
846 This enables the legacy 16-bit UID syscall wrappers.
847
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700848config SYSCTL_SYSCALL
Randy Dunlap08470622006-09-30 23:28:13 -0700849 bool "Sysctl syscall support" if EMBEDDED
Eric W. Biederman26a70342009-11-05 05:26:41 -0800850 depends on PROC_SYSCTL
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800851 default y
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700852 select SYSCTL
853 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800854 sys_sysctl uses binary paths that have been found challenging
855 to properly maintain and use. The interface in /proc/sys
856 using paths with ascii names is now the primary path to this
857 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700858
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800859 Almost nothing using the binary sysctl interface so if you are
860 trying to save some space it is probably safe to disable this,
861 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700862
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800863 If unsure say Y here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865config KALLSYMS
Jesper Juhl979c6a12006-12-12 19:25:11 +0100866 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 default y
868 help
869 Say Y here to let the kernel print out symbolic crash information and
870 symbolic stack backtraces. This increases the size of the kernel
871 somewhat, as all symbols have to be loaded into the kernel image.
872
873config KALLSYMS_ALL
874 bool "Include all symbols in kallsyms"
875 depends on DEBUG_KERNEL && KALLSYMS
876 help
877 Normally kallsyms only contains the symbols of functions, for nicer
878 OOPS messages. Some debuggers can use kallsyms for other
Jesper Juhlf9f97bc2005-07-20 05:43:05 +0200879 symbols too: say Y here to include all symbols, if you need them
880 and you don't care about adding 300k to the size of your kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
882 Say N.
883
884config KALLSYMS_EXTRA_PASS
885 bool "Do an extra kallsyms pass"
886 depends on KALLSYMS
887 help
888 If kallsyms is not working correctly, the build will fail with
889 inconsistent kallsyms data. If that occurs, log a bug report and
890 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
891 Always say N here unless you find a bug in kallsyms, which must be
892 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
893 you wait for kallsyms to be fixed.
894
Matt Mackalld59745c2005-05-01 08:59:02 -0700895
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -0800896config HOTPLUG
897 bool "Support for hot-pluggable devices" if EMBEDDED
898 default y
899 help
900 This option is provided for the case where no hotplug or uevent
901 capabilities is wanted by the kernel. You should only consider
902 disabling this option for embedded systems that do not use modules, a
903 dynamic /dev tree, or dynamic device discovery. Just say Y.
904
Matt Mackalld59745c2005-05-01 08:59:02 -0700905config PRINTK
906 default y
907 bool "Enable support for printk" if EMBEDDED
908 help
909 This option enables normal printk support. Removing it
910 eliminates most of the message strings from the kernel image
911 and makes the kernel more or less silent. As this makes it
912 very difficult to diagnose system problems, saying N here is
913 strongly discouraged.
914
Matt Mackallc8538a72005-05-01 08:59:01 -0700915config BUG
916 bool "BUG() support" if EMBEDDED
917 default y
918 help
919 Disabling this option eliminates support for BUG and WARN, reducing
920 the size of your kernel image and potentially quietly ignoring
921 numerous fatal conditions. You should only consider disabling this
922 option for embedded systems with no facilities for reporting errors.
923 Just say Y.
924
Matt Mackall708e9a72006-01-08 01:05:25 -0800925config ELF_CORE
926 default y
927 bool "Enable ELF core dumps" if EMBEDDED
928 help
929 Enable support for generating core dumps. Disabling saves about 4k.
930
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +0200931config PCSPKR_PLATFORM
932 bool "Enable PC-Speaker support" if EMBEDDED
933 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
934 default y
935 help
936 This option allows to disable the internal PC-Speaker
937 support, saving some memory.
938
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939config BASE_FULL
940 default y
941 bool "Enable full-sized data structures for core" if EMBEDDED
942 help
943 Disabling this option reduces the size of miscellaneous core
944 kernel data structures. This saves memory on small machines,
945 but may reduce performance.
946
947config FUTEX
948 bool "Enable futex support" if EMBEDDED
949 default y
Ingo Molnar23f78d42006-06-27 02:54:53 -0700950 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 help
952 Disabling this option will cause the kernel to be built without
953 support for "fast userspace mutexes". The resulting kernel may not
954 run glibc-based applications correctly.
955
956config EPOLL
957 bool "Enable eventpoll support" if EMBEDDED
958 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700959 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 help
961 Disabling this option will cause the kernel to be built without
962 support for epoll family of system calls.
963
Davide Libenzifba2afa2007-05-10 22:23:13 -0700964config SIGNALFD
965 bool "Enable signalfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700966 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -0700967 default y
968 help
969 Enable the signalfd() system call that allows to receive signals
970 on a file descriptor.
971
972 If unsure, say Y.
973
Davide Libenzib215e282007-05-10 22:23:16 -0700974config TIMERFD
975 bool "Enable timerfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700976 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -0700977 default y
978 help
979 Enable the timerfd() system call that allows to receive timer
980 events on a file descriptor.
981
982 If unsure, say Y.
983
Davide Libenzie1ad7462007-05-10 22:23:19 -0700984config EVENTFD
985 bool "Enable eventfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700986 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -0700987 default y
988 help
989 Enable the eventfd() system call that allows to receive both
990 kernel notification (ie. KAIO) or userspace notifications.
991
992 If unsure, say Y.
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994config SHMEM
995 bool "Use full shmem filesystem" if EMBEDDED
996 default y
997 depends on MMU
998 help
999 The shmem is an internal filesystem used to manage shared memory.
1000 It is backed by swap and manages resource limits. It is also exported
1001 to userspace as tmpfs if TMPFS is enabled. Disabling this
1002 option replaces shmem and tmpfs with the much simpler ramfs code,
1003 which may be appropriate on small systems without swap.
1004
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001005config AIO
1006 bool "Enable AIO support" if EMBEDDED
1007 default y
1008 help
1009 This option enables POSIX asynchronous I/O which may by used
1010 by some high performance threaded applications. Disabling
1011 this option saves about 7k.
1012
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001013config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001014 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001015 help
1016 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001017
Peter Zijlstra906010b2009-09-21 16:08:49 +02001018config PERF_USE_VMALLOC
1019 bool
1020 help
1021 See tools/perf/design.txt for details
1022
Ingo Molnar57c0c152009-09-21 12:20:38 +02001023menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001024
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001025config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001026 bool "Kernel performance events and counters"
1027 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001028 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001029 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001030 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001031 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001032 Enable kernel support for various performance events provided
1033 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001034
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001035 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001036 use of generic tracepoints.
1037
1038 Most modern CPUs support performance events via performance
1039 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001040 types of hw events: such as instructions executed, cachemisses
1041 suffered, or branches mis-predicted - without slowing down the
1042 kernel or applications. These registers can also trigger interrupts
1043 when a threshold number of events have passed - and can thus be
1044 used to profile the code that runs on that CPU.
1045
Ingo Molnar57c0c152009-09-21 12:20:38 +02001046 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001047 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001048 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001049 provides per task and per CPU counters, and it provides event
1050 capabilities on top of those.
1051
1052 Say Y if unsure.
1053
Ingo Molnar57c0c152009-09-21 12:20:38 +02001054config PERF_COUNTERS
1055 bool "Kernel performance counters (old config option)"
1056 depends on HAVE_PERF_EVENTS
1057 help
1058 This config has been obsoleted by the PERF_EVENTS
1059 config option - please see that one for details.
1060
1061 It has no effect on the kernel whether you enable
1062 it or not, it is a compatibility placeholder.
1063
1064 Say N if unsure.
1065
Peter Zijlstra906010b2009-09-21 16:08:49 +02001066config DEBUG_PERF_USE_VMALLOC
1067 default n
1068 bool "Debug: use vmalloc to back perf mmap() buffers"
1069 depends on PERF_EVENTS && DEBUG_KERNEL
1070 select PERF_USE_VMALLOC
1071 help
1072 Use vmalloc memory to back perf mmap() buffers.
1073
1074 Mostly useful for debugging the vmalloc code on platforms
1075 that don't require it.
1076
1077 Say N if unsure.
1078
Thomas Gleixner0793a612008-12-04 20:12:29 +01001079endmenu
1080
Christoph Lameterf8891e52006-06-30 01:55:45 -07001081config VM_EVENT_COUNTERS
1082 default y
1083 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1084 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001085 VM event counters are needed for event counts to be shown.
1086 This option allows the disabling of the VM event counters
1087 on EMBEDDED systems. /proc/vmstat will only show page counts
1088 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001089
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001090config PCI_QUIRKS
1091 default y
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001092 bool "Enable PCI quirk workarounds" if EMBEDDED
1093 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001094 help
1095 This enables workarounds for various PCI chipset
1096 bugs/quirks. Disable this only if your target machine is
1097 unaffected by PCI quirks.
1098
Christoph Lameter41ecc552007-05-09 02:32:44 -07001099config SLUB_DEBUG
1100 default y
1101 bool "Enable SLUB debugging support" if EMBEDDED
Christoph Lameterf6acb632008-04-29 16:16:06 -07001102 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001103 help
1104 SLUB has extensive debug support features. Disabling these can
1105 result in significant savings in code size. This also disables
1106 SLUB sysfs support. /sys/slab will not exist and there will be
1107 no support for cache validation etc.
1108
Randy Dunlapb943c462009-03-10 12:55:46 -07001109config COMPAT_BRK
1110 bool "Disable heap randomization"
1111 default y
1112 help
1113 Randomizing heap placement makes heap exploits harder, but it
1114 also breaks ancient binaries (including anything libc5 based).
1115 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001116 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001117 /proc/sys/kernel/randomize_va_space to 2.
1118
1119 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1120
Christoph Lameter81819f02007-05-06 14:49:36 -07001121choice
1122 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001123 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001124 help
1125 This option allows to select a slab allocator.
1126
1127config SLAB
1128 bool "SLAB"
1129 help
1130 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001131 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001132 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001133
1134config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001135 bool "SLUB (Unqueued Allocator)"
1136 help
1137 SLUB is a slab allocator that minimizes cache line usage
1138 instead of managing queues of cached objects (SLAB approach).
1139 Per cpu caching is realized using slabs of objects instead
1140 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001141 and has enhanced diagnostics. SLUB is the default choice for
1142 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001143
1144config SLOB
Paul Mundt84a01c22007-07-15 23:38:24 -07001145 depends on EMBEDDED
Christoph Lameter81819f02007-05-06 14:49:36 -07001146 bool "SLOB (Simple Allocator)"
1147 help
Matt Mackall37291452008-02-04 22:29:38 -08001148 SLOB replaces the stock allocator with a drastically simpler
1149 allocator. SLOB is generally more space efficient but
1150 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001151
1152endchoice
1153
Jie Zhangea637632009-12-14 18:00:02 -08001154config MMAP_ALLOW_UNINITIALIZED
1155 bool "Allow mmapped anonymous memory to be uninitialized"
1156 depends on EMBEDDED && !MMU
1157 default n
1158 help
1159 Normally, and according to the Linux spec, anonymous memory obtained
1160 from mmap() has it's contents cleared before it is passed to
1161 userspace. Enabling this config option allows you to request that
1162 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1163 providing a huge performance boost. If this option is not enabled,
1164 then the flag will be ignored.
1165
1166 This is taken advantage of by uClibc's malloc(), and also by
1167 ELF-FDPIC binfmt's brk and stack allocator.
1168
1169 Because of the obvious security issues, this option should only be
1170 enabled on embedded devices where you control what is run in
1171 userspace. Since that isn't generally a problem on no-MMU systems,
1172 it is normally safe to say Y here.
1173
1174 See Documentation/nommu-mmap.txt for more information.
1175
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001176config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001177 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001178 help
1179 Say Y here to enable the extended profiling support mechanisms used
1180 by profilers such as OProfile.
1181
Ingo Molnar5f87f112008-07-23 14:15:22 +02001182#
1183# Place an empty function call at each tracepoint site. Can be
1184# dynamically changed for a probe function.
1185#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001186config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001187 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001188
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001189source "arch/Kconfig"
1190
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191endmenu # General setup
1192
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001193config HAVE_GENERIC_DMA_COHERENT
1194 bool
1195 default n
1196
Linus Torvalds158a9622008-01-02 13:04:48 -08001197config SLABINFO
1198 bool
1199 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001200 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001201 default y
1202
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001203config RT_MUTEXES
1204 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206config BASE_SMALL
1207 int
1208 default 0 if BASE_FULL
1209 default 1 if !BASE_FULL
1210
Jan Engelhardt66da5732007-07-15 23:39:29 -07001211menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 bool "Enable loadable module support"
1213 help
1214 Kernel modules are small pieces of compiled code which can
1215 be inserted in the running kernel, rather than being
1216 permanently built into the kernel. You use the "modprobe"
1217 tool to add (and sometimes remove) them. If you say Y here,
1218 many parts of the kernel can be built as modules (by
1219 answering M instead of Y where indicated): this is most
1220 useful for infrequently used options which are not required
1221 for booting. For more information, see the man pages for
1222 modprobe, lsmod, modinfo, insmod and rmmod.
1223
1224 If you say Y here, you will need to run "make
1225 modules_install" to put the modules under /lib/modules/
1226 where modprobe can find them (you may need to be root to do
1227 this).
1228
1229 If unsure, say Y.
1230
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001231if MODULES
1232
Linus Torvalds826e4502008-05-04 17:04:16 -07001233config MODULE_FORCE_LOAD
1234 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001235 default n
1236 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001237 Allow loading of modules without version information (ie. modprobe
1238 --force). Forced module loading sets the 'F' (forced) taint flag and
1239 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001240
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241config MODULE_UNLOAD
1242 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 help
1244 Without this option you will not be able to unload any
1245 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001246 anyway), which makes your kernel smaller, faster
1247 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248
1249config MODULE_FORCE_UNLOAD
1250 bool "Forced module unloading"
1251 depends on MODULE_UNLOAD && EXPERIMENTAL
1252 help
1253 This option allows you to force a module to unload, even if the
1254 kernel believes it is unsafe: the kernel will remove the module
1255 without waiting for anyone to stop using it (using the -f option to
1256 rmmod). This is mainly for kernel developers and desperate users.
1257 If unsure, say N.
1258
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001260 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 help
1262 Usually, you have to use modules compiled with your kernel.
1263 Saying Y here makes it sometimes possible to use modules
1264 compiled for different kernels, by adding enough information
1265 to the modules to (hopefully) spot any changes which would
1266 make them incompatible with the kernel you are running. If
1267 unsure, say N.
1268
1269config MODULE_SRCVERSION_ALL
1270 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 help
1272 Modules which contain a MODULE_VERSION get an extra "srcversion"
1273 field inserted into their modinfo section, which contains a
1274 sum of the source files which made it. This helps maintainers
1275 see exactly which source was used to build a module (since
1276 others sometimes change the module source without updating
1277 the version). With this option, such a "srcversion" field
1278 will be created for all modules. If unsure, say N.
1279
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001280endif # MODULES
1281
Rusty Russell98a79d62008-12-13 21:19:41 +10301282config INIT_ALL_POSSIBLE
1283 bool
1284 help
1285 Back when each arch used to define their own cpu_online_map and
1286 cpu_possible_map, some of them chose to initialize cpu_possible_map
1287 with all 1s, and others with all 0s. When they were centralised,
1288 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001289 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291config STOP_MACHINE
1292 bool
1293 default y
1294 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1295 help
1296 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001297
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001298source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001299
1300config PREEMPT_NOTIFIERS
1301 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001302
Steffen Klassert16295be2010-01-06 19:47:10 +11001303config PADATA
1304 depends on SMP
1305 bool
1306
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001307source "kernel/Kconfig.locks"