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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' 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
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config HAVE_IRQ_WORK
24 bool
25
26config IRQ_WORK
27 bool
28 depends on HAVE_IRQ_WORK
29
David Daney1dbdc6f2012-04-19 14:59:57 -070030config BUILDTIME_EXTABLE_SORT
31 bool
32
Al Boldiff0cfc62007-07-31 00:39:23 -070033menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35config EXPERIMENTAL
36 bool "Prompt for development and/or incomplete code/drivers"
37 ---help---
38 Some of the various things that Linux supports (such as network
39 drivers, file systems, network protocols, etc.) can be in a state
40 of development where the functionality, stability, or the level of
41 testing is not yet high enough for general use. This is usually
42 known as the "alpha-test" phase among developers. If a feature is
43 currently in alpha-test, then the developers usually discourage
44 uninformed widespread use of this feature by the general public to
45 avoid "Why doesn't this work?" type mail messages. However, active
46 testing and use of these systems is welcomed. Just be aware that it
47 may not meet the normal level of reliability or it may fail to work
48 in some special cases. Detailed bug reports from people familiar
49 with the kernel internals are usually welcomed by the developers
50 (before submitting bug reports, please read the documents
51 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
52 <file:Documentation/BUG-HUNTING>, and
53 <file:Documentation/oops-tracing.txt> in the kernel source).
54
55 This option will also make obsoleted drivers available. These are
56 drivers that have been replaced by something else, and/or are
57 scheduled to be removed in a future kernel release.
58
59 Unless you intend to help test and develop a feature or driver that
60 falls into this category, or you have a situation that requires
61 using these features, you should probably say N here, which will
62 cause the configurator to present you with fewer choices. If
63 you say Y here, you will be offered the choice of using features or
64 drivers that are currently considered to be in the alpha-test phase.
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066config BROKEN
67 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69config BROKEN_ON_SMP
70 bool
71 depends on BROKEN || !SMP
72 default y
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074config INIT_ENV_ARG_LIMIT
75 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070076 default 32 if !UML
77 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080079 Maximum of each of the number of arguments and environment
80 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Roland McGrath84336462009-12-21 16:24:06 -080083config CROSS_COMPILE
84 string "Cross-compiler tool prefix"
85 help
86 Same as running 'make CROSS_COMPILE=prefix-' but stored for
87 default make runs in this kernel build directory. You don't
88 need to set this unless you want the configured kernel build
89 directory to select the cross-compiler automatically.
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091config LOCALVERSION
92 string "Local version - append to kernel release"
93 help
94 Append an extra string to the end of your kernel version.
95 This will show up when you type uname, for example.
96 The string you set here will be appended after the contents of
97 any files with a filename matching localversion* in your
98 object and source tree, in that order. Your total string can
99 be a maximum of 64 characters.
100
Ryan Andersonaaebf432005-07-31 04:57:49 -0400101config LOCALVERSION_AUTO
102 bool "Automatically append version information to the version string"
103 default y
104 help
105 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 release tree by looking for git tags that belong to the current
107 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400108
109 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400111 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200112 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400113
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200114 (The actual string used here is the first eight characters produced
115 by running the command:
116
117 $ git rev-parse --verify HEAD
118
119 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400120
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800121config HAVE_KERNEL_GZIP
122 bool
123
124config HAVE_KERNEL_BZIP2
125 bool
126
127config HAVE_KERNEL_LZMA
128 bool
129
Lasse Collin3ebe1242011-01-12 17:01:23 -0800130config HAVE_KERNEL_XZ
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
Lasse Collin3ebe1242011-01-12 17:01:23 -0800139 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || 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.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700170 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800171 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
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700179 This compression algorithm's ratio is best. Decompression speed
180 is between gzip and bzip2. Compression is slowest.
181 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100182
Lasse Collin3ebe1242011-01-12 17:01:23 -0800183config KERNEL_XZ
184 bool "XZ"
185 depends on HAVE_KERNEL_XZ
186 help
187 XZ uses the LZMA2 algorithm and instruction set specific
188 BCJ filters which can improve compression ratio of executable
189 code. The size of the kernel is about 30% smaller with XZ in
190 comparison to gzip. On architectures for which there is a BCJ
191 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
192 will create a few percent smaller kernel than plain LZMA.
193
194 The speed is about the same as with LZMA: The decompression
195 speed of XZ is better than that of bzip2 but worse than gzip
196 and LZO. Compression is slow.
197
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800198config KERNEL_LZO
199 bool "LZO"
200 depends on HAVE_KERNEL_LZO
201 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700202 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200203 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800204 (both compression and decompression) is the fastest.
205
Alain Knaff30d65db2009-01-04 22:46:17 +0100206endchoice
207
Josh Triplettbd5dc172011-06-15 15:08:28 -0700208config DEFAULT_HOSTNAME
209 string "Default hostname"
210 default "(none)"
211 help
212 This option determines the default system hostname before userspace
213 calls sethostname(2). The kernel traditionally uses "(none)" here,
214 but you may wish to use a different default here to make a minimal
215 system more usable with less configuration.
216
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217config SWAP
218 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200219 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 default y
221 help
222 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100223 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 used to provide more virtual memory than the actual RAM present
225 in your computer. If unsure say Y.
226
227config SYSVIPC
228 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 ---help---
230 Inter Process Communication is a suite of library functions and
231 system calls which let processes (running programs) synchronize and
232 exchange information. It is generally considered to be a good thing,
233 and some programs won't run unless you say Y here. In particular, if
234 you want to run the DOS emulator dosemu under Linux (read the
235 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
236 you'll need to say Y here.
237
238 You can find documentation about IPC with "info ipc" and also in
239 section 6.4 of the Linux Programmer's Guide, available from
240 <http://www.tldp.org/guides.html>.
241
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800242config SYSVIPC_SYSCTL
243 bool
244 depends on SYSVIPC
245 depends on SYSCTL
246 default y
247
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248config POSIX_MQUEUE
249 bool "POSIX Message Queues"
250 depends on NET && EXPERIMENTAL
251 ---help---
252 POSIX variant of message queues is a part of IPC. In POSIX message
253 queues every message has a priority which decides about succession
254 of receiving it by a process. If you want to compile and run
255 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200256 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 POSIX message queues are visible as a filesystem called 'mqueue'
259 and can be mounted somewhere if you want to do filesystem
260 operations on message queues.
261
262 If unsure, say Y.
263
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700264config POSIX_MQUEUE_SYSCTL
265 bool
266 depends on POSIX_MQUEUE
267 depends on SYSCTL
268 default y
269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270config BSD_PROCESS_ACCT
271 bool "BSD Process Accounting"
272 help
273 If you say Y here, a user level program will be able to instruct the
274 kernel (via a special system call) to write process accounting
275 information to a file: whenever a process exits, information about
276 that process will be appended to the file by the kernel. The
277 information includes things such as creation time, owning user,
278 command name, memory usage, controlling terminal etc. (the complete
279 list is in the struct acct in <file:include/linux/acct.h>). It is
280 up to the user level program to do useful things with this
281 information. This is generally a good idea, so say Y.
282
283config BSD_PROCESS_ACCT_V3
284 bool "BSD Process Accounting version 3 file format"
285 depends on BSD_PROCESS_ACCT
286 default n
287 help
288 If you say Y here, the process accounting information is written
289 in a new file format that also logs the process IDs of each
290 process and it's parent. Note that this file format is incompatible
291 with previous v0/v1/v2 file formats, so you will need updated tools
292 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300293 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530295config FHANDLE
296 bool "open by fhandle syscalls"
297 select EXPORTFS
298 help
299 If you say Y here, a user level program will be able to map
300 file names to handle and then later use the handle for
301 different file system operations. This is useful in implementing
302 userspace file servers, which now track files using handles instead
303 of names. The handle would remain the same even if file names
304 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
305 syscalls.
306
Shailabh Nagarc7572492006-07-14 00:24:40 -0700307config TASKSTATS
308 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
309 depends on NET
310 default n
311 help
312 Export selected statistics for tasks/processes through the
313 generic netlink interface. Unlike BSD process accounting, the
314 statistics are available during the lifetime of tasks/processes as
315 responses to commands. Like BSD accounting, they are sent to user
316 space on task exit.
317
318 Say N if unsure.
319
Shailabh Nagarca74e922006-07-14 00:24:36 -0700320config TASK_DELAY_ACCT
321 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700322 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700323 help
324 Collect information on time spent by a task waiting for system
325 resources like cpu, synchronous block I/O completion and swapping
326 in pages. Such statistics can help in setting a task's priorities
327 relative to other tasks for cpu, io, rss limits etc.
328
329 Say N if unsure.
330
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800331config TASK_XACCT
332 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
333 depends on TASKSTATS
334 help
335 Collect extended task accounting data and send the data
336 to userland for processing over the taskstats interface.
337
338 Say N if unsure.
339
340config TASK_IO_ACCOUNTING
341 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
342 depends on TASK_XACCT
343 help
344 Collect information on the number of bytes of storage I/O which this
345 task has caused.
346
347 Say N if unsure.
348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349config AUDIT
350 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100351 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 help
353 Enable auditing infrastructure that can be used with another
354 kernel subsystem, such as SELinux (which requires this for
355 logging of avc messages output). Does not do system-call
356 auditing without CONFIG_AUDITSYSCALL.
357
358config AUDITSYSCALL
359 bool "Enable system-call auditing support"
Nathaniel Husted29ef73b2012-01-03 14:23:09 -0500360 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 default y if SECURITY_SELINUX
362 help
363 Enable low-overhead system-call auditing infrastructure that
364 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500365 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Eric Paris939a67f2009-12-17 20:12:06 -0500367config AUDIT_WATCH
368 def_bool y
369 depends on AUDITSYSCALL
370 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371
Al Viro74c3cbe2007-07-22 08:04:18 -0400372config AUDIT_TREE
373 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400374 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500375 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400376
Eric Paris633b4542012-01-03 14:23:08 -0500377config AUDIT_LOGINUID_IMMUTABLE
378 bool "Make audit loginuid immutable"
379 depends on AUDIT
380 help
Linus Torvaldsf429ee32012-01-17 16:06:51 -0800381 The config option toggles if a task setting its loginuid requires
Eric Paris633b4542012-01-03 14:23:08 -0500382 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
383 but should instead only allow setting its loginuid if it was never
384 previously set. On systems which use systemd or a similar central
385 process to restart login services this should be set to true. On older
386 systems in which an admin would typically have to directly stop and
387 start processes this should be set to false. Setting this to true allows
388 one to drop potentially dangerous capabilites from the login tasks,
389 but may not be backwards compatible with older init systems.
390
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000391source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200392source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000393
Mike Travisc903ff82009-01-15 12:28:29 -0800394menu "RCU Subsystem"
395
396choice
397 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700398 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800399
Mike Travisc903ff82009-01-15 12:28:29 -0800400config TREE_RCU
401 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700402 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800403 help
404 This option selects the RCU implementation that is
405 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700406 thousands of CPUs. It also scales down nicely to
407 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800408
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700409config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700410 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700411 depends on PREEMPT && SMP
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700412 help
413 This option selects the RCU implementation that is
414 designed for very large SMP systems with hundreds or
415 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700416 is also required. It also scales down nicely to
417 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700418
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700419config TINY_RCU
420 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700421 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700422 help
423 This option selects the RCU implementation that is
424 designed for UP systems from which real-time response
425 is not required. This option greatly reduces the
426 memory footprint of RCU.
427
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700428config TINY_PREEMPT_RCU
429 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700430 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700431 help
432 This option selects the RCU implementation that is designed
433 for real-time UP systems. This option greatly reduces the
434 memory footprint of RCU.
435
Mike Travisc903ff82009-01-15 12:28:29 -0800436endchoice
437
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700438config PREEMPT_RCU
439 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
440 help
441 This option enables preemptible-RCU code that is common between
442 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
443
Mike Travisc903ff82009-01-15 12:28:29 -0800444config RCU_FANOUT
445 int "Tree-based hierarchical RCU fanout value"
446 range 2 64 if 64BIT
447 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700448 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800449 default 64 if 64BIT
450 default 32 if !64BIT
451 help
452 This option controls the fanout of hierarchical implementations
453 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700454 large numbers of CPUs. This value must be at least the fourth
455 root of NR_CPUS, which allows NR_CPUS to be insanely large.
456 The default value of RCU_FANOUT should be used for production
457 systems, but if you are stress-testing the RCU implementation
458 itself, small RCU_FANOUT values allow you to test large-system
459 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800460
461 Select a specific number if testing RCU itself.
462 Take the default if unsure.
463
Paul E. McKenney8932a632012-04-19 12:20:14 -0700464config RCU_FANOUT_LEAF
465 int "Tree-based hierarchical RCU leaf-level fanout value"
466 range 2 RCU_FANOUT if 64BIT
467 range 2 RCU_FANOUT if !64BIT
468 depends on TREE_RCU || TREE_PREEMPT_RCU
469 default 16
470 help
471 This option controls the leaf-level fanout of hierarchical
472 implementations of RCU, and allows trading off cache misses
473 against lock contention. Systems that synchronize their
474 scheduling-clock interrupts for energy-efficiency reasons will
475 want the default because the smaller leaf-level fanout keeps
476 lock contention levels acceptably low. Very large systems
477 (hundreds or thousands of CPUs) will instead want to set this
478 value to the maximum value possible in order to reduce the
479 number of cache misses incurred during RCU's grace-period
480 initialization. These systems tend to run CPU-bound, and thus
481 are not helped by synchronized interrupts, and thus tend to
482 skew them, which reduces lock contention enough that large
483 leaf-level fanouts work well.
484
485 Select a specific number if testing RCU itself.
486
487 Select the maximum permissible value for large systems.
488
489 Take the default if unsure.
490
Mike Travisc903ff82009-01-15 12:28:29 -0800491config RCU_FANOUT_EXACT
492 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700493 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800494 default n
495 help
496 This option forces use of the exact RCU_FANOUT value specified,
497 regardless of imbalances in the hierarchy. This is useful for
498 testing RCU itself, and might one day be useful on systems with
499 strong NUMA behavior.
500
501 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
502
503 Say N if unsure.
504
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800505config RCU_FAST_NO_HZ
506 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700507 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800508 default n
509 help
510 This option causes RCU to attempt to accelerate grace periods
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700511 in order to allow CPUs to enter dynticks-idle state more
512 quickly. On the other hand, this option increases the overhead
513 of the dynticks-idle checking, particularly on systems with
514 large numbers of CPUs.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800515
516 Say Y if energy efficiency is critically important, particularly
517 if you have relatively few CPUs.
518
519 Say N if you are unsure.
520
Mike Travisc903ff82009-01-15 12:28:29 -0800521config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700522 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800523 select DEBUG_FS
524 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700525 This option provides tracing for the TREE_RCU and
526 TREE_PREEMPT_RCU implementations, permitting Makefile to
527 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800528
Paul E. McKenney24278d12010-09-27 17:25:23 -0700529config RCU_BOOST
530 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800531 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700532 default n
533 help
534 This option boosts the priority of preempted RCU readers that
535 block the current preemptible RCU grace period for too long.
536 This option also prevents heavy loads from blocking RCU
537 callback invocation for all flavors of RCU.
538
539 Say Y here if you are working with real-time apps or heavy loads
540 Say N here if you are unsure.
541
542config RCU_BOOST_PRIO
543 int "Real-time priority to boost RCU readers to"
544 range 1 99
545 depends on RCU_BOOST
546 default 1
547 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700548 This option specifies the real-time priority to which long-term
549 preempted RCU readers are to be boosted. If you are working
550 with a real-time application that has one or more CPU-bound
551 threads running at a real-time priority level, you should set
552 RCU_BOOST_PRIO to a priority higher then the highest-priority
553 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
554 of 1 is appropriate in the common case, which is real-time
555 applications that do not have any CPU-bound threads.
556
557 Some real-time applications might not have a single real-time
558 thread that saturates a given CPU, but instead might have
559 multiple real-time threads that, taken together, fully utilize
560 that CPU. In this case, you should set RCU_BOOST_PRIO to
561 a priority higher than the lowest-priority thread that is
562 conspiring to prevent the CPU from running any non-real-time
563 tasks. For example, if one thread at priority 10 and another
564 thread at priority 5 are between themselves fully consuming
565 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
566 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700567
568 Specify the real-time priority, or take the default if unsure.
569
570config RCU_BOOST_DELAY
571 int "Milliseconds to delay boosting after RCU grace-period start"
572 range 0 3000
573 depends on RCU_BOOST
574 default 500
575 help
576 This option specifies the time to wait after the beginning of
577 a given grace period before priority-boosting preempted RCU
578 readers blocking that grace period. Note that any RCU reader
579 blocking an expedited RCU grace period is boosted immediately.
580
581 Accept the default if unsure.
582
Mike Travisc903ff82009-01-15 12:28:29 -0800583endmenu # "RCU Subsystem"
584
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700586 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 ---help---
588 This option enables the complete Linux kernel ".config" file
589 contents to be saved in the kernel. It provides documentation
590 of which kernel options are used in a running kernel or in an
591 on-disk kernel. This information can be extracted from the kernel
592 image file with the script scripts/extract-ikconfig and used as
593 input to rebuild the current kernel or to build another kernel.
594 It can also be extracted from a running kernel by reading
595 /proc/config.gz if enabled (below).
596
597config IKCONFIG_PROC
598 bool "Enable access to .config through /proc/config.gz"
599 depends on IKCONFIG && PROC_FS
600 ---help---
601 This option enables access to the kernel configuration file
602 through /proc/config.gz.
603
Alistair John Strachan794543a2007-05-08 00:31:15 -0700604config LOG_BUF_SHIFT
605 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
606 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700607 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700608 help
609 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700610 Examples:
611 17 => 128 KB
612 16 => 64 KB
613 15 => 32 KB
614 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700615 13 => 8 KB
616 12 => 4 KB
617
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800618#
619# Architectures with an unreliable sched_clock() should select this:
620#
621config HAVE_UNSTABLE_SCHED_CLOCK
622 bool
623
Li Zefan23964d22009-01-15 13:50:58 -0800624menuconfig CGROUPS
625 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800626 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700627 help
Li Zefan23964d22009-01-15 13:50:58 -0800628 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800629 use with process control subsystems such as Cpusets, CFS, memory
630 controls or device isolation.
631 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800632 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800633 - Documentation/cgroups/ (features for grouping, isolation
634 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700635
636 Say N if unsure.
637
Li Zefan23964d22009-01-15 13:50:58 -0800638if CGROUPS
639
Paul Menage006cb992007-10-18 23:39:43 -0700640config CGROUP_DEBUG
641 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700642 default n
Paul Menage006cb992007-10-18 23:39:43 -0700643 help
644 This option enables a simple cgroup subsystem that
645 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800646 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700647
Li Zefan23964d22009-01-15 13:50:58 -0800648 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700649
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700650config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800651 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800652 help
653 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700654 cgroup.
655
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700656config CGROUP_DEVICE
657 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700658 help
659 Provides a cgroup implementing whitelists for devices which
660 a process in the cgroup can mknod or open.
661
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662config CPUSETS
663 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700665 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 allow dynamically partitioning a system into sets of CPUs and
667 Memory Nodes and assigning tasks to run only within those sets.
668 This is primarily useful on large SMP or NUMA systems.
669
670 Say N if unsure.
671
Li Zefan23964d22009-01-15 13:50:58 -0800672config PROC_PID_CPUSET
673 bool "Include legacy /proc/<pid>/cpuset file"
674 depends on CPUSETS
675 default y
676
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100677config CGROUP_CPUACCT
678 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100679 help
680 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800681 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100682
Pavel Emelianove552b662008-02-07 00:13:49 -0800683config RESOURCE_COUNTERS
684 bool "Resource counters"
685 help
686 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800687 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800688
Balbir Singh00f0b822008-03-04 14:28:39 -0800689config CGROUP_MEM_RES_CTLR
690 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700691 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700692 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800693 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700694 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100695 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800696
697 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700698 associated with each page of memory in the system. By this,
699 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
700 usage tracking struct at boot. Total amount of this is printed out
701 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800702
703 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700704 sure you need the memory resource controller. Even when you enable
705 this, you can set "cgroup_disable=memory" at your boot option to
706 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800707 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800708
Balbir Singhcf475ad2008-04-29 01:00:16 -0700709 This config option also selects MM_OWNER config option, which
710 could in turn add some fork/exit overhead.
711
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800712config CGROUP_MEM_RES_CTLR_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700713 bool "Memory Resource Controller Swap Extension"
714 depends on CGROUP_MEM_RES_CTLR && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800715 help
716 Add swap management feature to memory resource controller. When you
717 enable this, you can limit mem+swap usage per cgroup. In other words,
718 when you disable this, memory resource controller has no cares to
719 usage of swap...a process can exhaust all of the swap. This extension
720 is useful when you want to avoid exhaustion swap but this itself
721 adds more overheads and consumes memory for remembering information.
722 Especially if you use 32bit system or small memory system, please
723 be careful about enabling this. When memory resource controller
724 is disabled by boot option, this will be automatically disabled and
725 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700726 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700727 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
728 size is 4096bytes, 512k per 1Gbytes of swap.
Michal Hockoa42c3902010-11-24 12:57:08 -0800729config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
730 bool "Memory Resource Controller Swap Extension enabled by default"
731 depends on CGROUP_MEM_RES_CTLR_SWAP
732 default y
733 help
734 Memory Resource Controller Swap Extension comes with its price in
735 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700736 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800737 and let the user enable it by swapaccount boot command line
738 parameter should have this option unselected.
739 For those who want to have the feature enabled by default should
740 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700741 then swapaccount=0 does the trick).
Glauber Costae5671df2011-12-11 21:47:01 +0000742config CGROUP_MEM_RES_CTLR_KMEM
743 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
744 depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
745 default n
746 help
747 The Kernel Memory extension for Memory Resource Controller can limit
748 the amount of memory used by kernel objects in the system. Those are
749 fundamentally different from the entities handled by the standard
750 Memory Controller, which are page-based, and can be swapped. Users of
751 the kmem extension can use it to guarantee that no group of processes
752 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800753
Stephane Eraniane5d13672011-02-14 11:20:01 +0200754config CGROUP_PERF
755 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
756 depends on PERF_EVENTS && CGROUPS
757 help
758 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800759 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200760 designated cpu.
761
762 Say N if unsure.
763
Dhaval Giani7c941432010-01-20 13:26:18 +0100764menuconfig CGROUP_SCHED
765 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100766 default n
767 help
768 This feature lets CPU scheduler recognize task groups and control CPU
769 bandwidth allocation to such task groups. It uses cgroups to group
770 tasks.
771
772if CGROUP_SCHED
773config FAIR_GROUP_SCHED
774 bool "Group scheduling for SCHED_OTHER"
775 depends on CGROUP_SCHED
776 default CGROUP_SCHED
777
Paul Turnerab84d312011-07-21 09:43:28 -0700778config CFS_BANDWIDTH
779 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
780 depends on EXPERIMENTAL
781 depends on FAIR_GROUP_SCHED
782 default n
783 help
784 This option allows users to define CPU bandwidth rates (limits) for
785 tasks running within the fair group scheduler. Groups with no limit
786 set are considered to be unconstrained and will run with no
787 restriction.
788 See tip/Documentation/scheduler/sched-bwc.txt for more information.
789
Dhaval Giani7c941432010-01-20 13:26:18 +0100790config RT_GROUP_SCHED
791 bool "Group scheduling for SCHED_RR/FIFO"
792 depends on EXPERIMENTAL
793 depends on CGROUP_SCHED
794 default n
795 help
796 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800797 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100798 schedule realtime tasks for non-root users until you allocate
799 realtime bandwidth for them.
800 See Documentation/scheduler/sched-rt-group.txt for more information.
801
802endif #CGROUP_SCHED
803
Vivek Goyalafc24d42010-04-26 19:27:56 +0200804config BLK_CGROUP
805 tristate "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700806 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200807 default n
808 ---help---
809 Generic block IO controller cgroup interface. This is the common
810 cgroup interface which should be used by various IO controlling
811 policies.
812
813 Currently, CFQ IO scheduler uses it to recognize task groups and
814 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400815 to such task groups. It is also used by bio throttling logic in
816 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200817
818 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400819 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000820 enabling proportional weight division of disk bandwidth in CFQ, set
821 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000822 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200823
824 See Documentation/cgroups/blkio-controller.txt for more information.
825
826config DEBUG_BLK_CGROUP
827 bool "Enable Block IO controller debugging"
828 depends on BLK_CGROUP
829 default n
830 ---help---
831 Enable some debugging help. Currently it exports additional stat
832 files in a cgroup which can be useful for debugging.
833
Li Zefan23964d22009-01-15 13:50:58 -0800834endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800835
Cyrill Gorcunov067bce12012-01-12 17:20:49 -0800836config CHECKPOINT_RESTORE
837 bool "Checkpoint/restore support" if EXPERT
838 default n
839 help
840 Enables additional kernel features in a sake of checkpoint/restore.
841 In particular it adds auxiliary prctl codes to setup process text,
842 data and heap segment sizes, and a few additional /proc filesystem
843 entries.
844
845 If unsure, say N here.
846
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700847menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800848 bool "Namespaces support" if EXPERT
849 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800850 help
851 Provides the way to make tasks work with different objects using
852 the same id. For example same IPC id may refer to different objects
853 or same user id or pid may refer to different tasks when used in
854 different namespaces.
855
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700856if NAMESPACES
857
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800858config UTS_NS
859 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700860 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800861 help
862 In this namespace tasks see different info provided with the
863 uname() system call
864
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800865config IPC_NS
866 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700867 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700868 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800869 help
870 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700871 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800872
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800873config USER_NS
874 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700875 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700876 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -0800877 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700878
Eric W. Biederman5673a942011-11-17 10:23:55 -0800879 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800880 help
881 This allows containers, i.e. vservers, to use user namespaces
882 to provide different user info for different servers.
883 If unsure, say N.
884
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800885config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700886 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700887 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800888 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300889 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100890 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800891 pid namespaces. This is a building block of containers.
892
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800893config NET_NS
894 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700895 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700896 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800897 help
898 Allow user space to create what appear to be multiple instances
899 of the network stack.
900
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700901endif # NAMESPACES
902
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700903config UIDGID_CONVERTED
904 # True if all of the selected software conmponents are known
905 # to have uid_t and gid_t converted to kuid_t and kgid_t
906 # where appropriate and are otherwise safe to use with
907 # the user namespace.
908 bool
909 default y
910
911 # List of kernel pieces that need user namespace work
912 # Features
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700913 depends on SYSVIPC = n
914 depends on IMA = n
915 depends on EVM = n
916 depends on KEYS = n
917 depends on AUDIT = n
918 depends on AUDITSYSCALL = n
919 depends on TASKSTATS = n
920 depends on TRACING = n
921 depends on FS_POSIX_ACL = n
922 depends on QUOTA = n
923 depends on QUOTACTL = n
924 depends on DEBUG_CREDENTIALS = n
925 depends on BSD_PROCESS_ACCT = n
926 depends on DRM = n
927 depends on PROC_EVENTS = n
928
929 # Networking
930 depends on NET = n
931 depends on NET_9P = n
932 depends on IPX = n
933 depends on PHONET = n
934 depends on NET_CLS_FLOW = n
935 depends on NETFILTER_XT_MATCH_OWNER = n
936 depends on NETFILTER_XT_MATCH_RECENT = n
937 depends on NETFILTER_XT_TARGET_LOG = n
938 depends on NETFILTER_NETLINK_LOG = n
939 depends on INET = n
940 depends on IPV6 = n
941 depends on IP_SCTP = n
942 depends on AF_RXRPC = n
943 depends on LLC2 = n
944 depends on NET_KEY = n
945 depends on INET_DIAG = n
946 depends on DNS_RESOLVER = n
947 depends on AX25 = n
948 depends on ATALK = n
949
950 # Filesystems
951 depends on USB_DEVICEFS = n
952 depends on USB_GADGETFS = n
953 depends on USB_FUNCTIONFS = n
954 depends on DEVTMPFS = n
955 depends on XENFS = n
956
957 depends on 9P_FS = n
958 depends on ADFS_FS = n
959 depends on AFFS_FS = n
960 depends on AFS_FS = n
961 depends on AUTOFS4_FS = n
962 depends on BEFS_FS = n
963 depends on BFS_FS = n
964 depends on BTRFS_FS = n
965 depends on CEPH_FS = n
966 depends on CIFS = n
967 depends on CODA_FS = n
968 depends on CONFIGFS_FS = n
969 depends on CRAMFS = n
970 depends on DEBUG_FS = n
971 depends on ECRYPT_FS = n
972 depends on EFS_FS = n
973 depends on EXOFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700974 depends on FAT_FS = n
975 depends on FUSE_FS = n
976 depends on GFS2_FS = n
977 depends on HFS_FS = n
978 depends on HFSPLUS_FS = n
979 depends on HPFS_FS = n
980 depends on HUGETLBFS = n
981 depends on ISO9660_FS = n
982 depends on JFFS2_FS = n
983 depends on JFS_FS = n
984 depends on LOGFS = n
985 depends on MINIX_FS = n
986 depends on NCP_FS = n
987 depends on NFSD = n
988 depends on NFS_FS = n
989 depends on NILFS2_FS = n
990 depends on NTFS_FS = n
991 depends on OCFS2_FS = n
992 depends on OMFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700993 depends on QNX4FS_FS = n
994 depends on QNX6FS_FS = n
995 depends on REISERFS_FS = n
996 depends on SQUASHFS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700997 depends on SYSV_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700998 depends on UBIFS_FS = n
999 depends on UDF_FS = n
1000 depends on UFS_FS = n
1001 depends on VXFS_FS = n
1002 depends on XFS_FS = n
1003
1004 depends on !UML || HOSTFS = n
1005
1006 # The rare drivers that won't build
1007 depends on AIRO = n
1008 depends on AIRO_CS = n
1009 depends on TUN = n
1010 depends on INFINIBAND_QIB = n
1011 depends on BLK_DEV_LOOP = n
1012 depends on ANDROID_BINDER_IPC = n
1013
1014 # Security modules
1015 depends on SECURITY_TOMOYO = n
1016 depends on SECURITY_APPARMOR = n
1017
Eric W. Biederman5673a942011-11-17 10:23:55 -08001018config UIDGID_STRICT_TYPE_CHECKS
1019 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001020 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001021 default n
1022 help
1023 While the nececessary conversions are being added to all subsystems this option allows
1024 the code to continue to build for unconverted subsystems.
1025
1026 Say Y here if you want the strict type checking enabled
1027
Mike Galbraith5091faa2010-11-30 14:18:03 +01001028config SCHED_AUTOGROUP
1029 bool "Automatic process group scheduling"
1030 select EVENTFD
1031 select CGROUPS
1032 select CGROUP_SCHED
1033 select FAIR_GROUP_SCHED
1034 help
1035 This option optimizes the scheduler for common desktop workloads by
1036 automatically creating and populating task groups. This separation
1037 of workloads isolates aggressive CPU burners (like build jobs) from
1038 desktop applications. Task group autogeneration is currently based
1039 upon task session.
1040
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001041config MM_OWNER
1042 bool
1043
1044config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001045 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001046 depends on SYSFS
1047 default n
1048 help
1049 This option adds code that switches the layout of the "block" class
1050 devices, to not show up in /sys/class/block/, but only in
1051 /sys/block/.
1052
1053 This switch is only active when the sysfs.deprecated=1 boot option is
1054 passed or the SYSFS_DEPRECATED_V2 option is set.
1055
1056 This option allows new kernels to run on old distributions and tools,
1057 which might get confused by /sys/class/block/. Since 2007/2008 all
1058 major distributions and tools handle this just fine.
1059
1060 Recent distributions and userspace tools after 2009/2010 depend on
1061 the existence of /sys/class/block/, and will not work with this
1062 option enabled.
1063
1064 Only if you are using a new kernel on an old distribution, you might
1065 need to say Y here.
1066
1067config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001068 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001069 default n
1070 depends on SYSFS
1071 depends on SYSFS_DEPRECATED
1072 help
1073 Enable deprecated sysfs by default.
1074
1075 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1076 option.
1077
1078 Only if you are using a new kernel on an old distribution, you might
1079 need to say Y here. Even then, odds are you would not need it
1080 enabled, you can always pass the boot option if absolutely necessary.
1081
1082config RELAY
1083 bool "Kernel->user space relay support (formerly relayfs)"
1084 help
1085 This option enables support for relay interface support in
1086 certain file systems (such as debugfs).
1087 It is designed to provide an efficient mechanism for tools and
1088 facilities to relay large amounts of data from kernel space to
1089 user space.
1090
1091 If unsure, say N.
1092
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001093config BLK_DEV_INITRD
1094 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1095 depends on BROKEN || !FRV
1096 help
1097 The initial RAM filesystem is a ramfs which is loaded by the
1098 boot loader (loadlin or lilo) and that is mounted as root
1099 before the normal boot procedure. It is typically used to
1100 load modules needed to mount the "real" root file system,
1101 etc. See <file:Documentation/initrd.txt> for details.
1102
1103 If RAM disk support (BLK_DEV_RAM) is also included, this
1104 also enables initial RAM disk (initrd) support and adds
1105 15 Kbytes (more on some other architectures) to the kernel size.
1106
1107 If unsure say Y.
1108
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001109if BLK_DEV_INITRD
1110
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001111source "usr/Kconfig"
1112
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001113endif
1114
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001115config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001116 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001117 help
1118 Enabling this option will pass "-Os" instead of "-O2" to gcc
1119 resulting in a smaller kernel.
1120
jkacur775a7222008-07-16 00:31:16 +02001121 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001122
Randy Dunlap08470622006-09-30 23:28:13 -07001123config SYSCTL
1124 bool
1125
Randy Dunlapb943c462009-03-10 12:55:46 -07001126config ANON_INODES
1127 bool
1128
David Rientjes6a108a12011-01-20 14:44:16 -08001129menuconfig EXPERT
1130 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001131 # Unhide debug options, to make the on-by-default options visible
1132 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 help
1134 This option allows certain base kernel options and settings
1135 to be disabled or tweaked. This is for specialized
1136 environments which can tolerate a "non-standard" kernel.
1137 Only use this if you really know what you are doing.
1138
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001139config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001140 bool "Enable 16-bit UID system calls" if EXPERT
David S. Miller09337f52008-04-26 03:17:12 -07001141 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 -07001142 default y
1143 help
1144 This enables the legacy 16-bit UID syscall wrappers.
1145
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001146config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001147 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001148 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001149 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001150 select SYSCTL
1151 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001152 sys_sysctl uses binary paths that have been found challenging
1153 to properly maintain and use. The interface in /proc/sys
1154 using paths with ascii names is now the primary path to this
1155 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001156
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001157 Almost nothing using the binary sysctl interface so if you are
1158 trying to save some space it is probably safe to disable this,
1159 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001160
WANG Congc736de62011-11-02 13:39:25 -07001161 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001162
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001164 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 default y
1166 help
1167 Say Y here to let the kernel print out symbolic crash information and
1168 symbolic stack backtraces. This increases the size of the kernel
1169 somewhat, as all symbols have to be loaded into the kernel image.
1170
1171config KALLSYMS_ALL
1172 bool "Include all symbols in kallsyms"
1173 depends on DEBUG_KERNEL && KALLSYMS
1174 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001175 Normally kallsyms only contains the symbols of functions for nicer
1176 OOPS messages and backtraces (i.e., symbols from the text and inittext
1177 sections). This is sufficient for most cases. And only in very rare
1178 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1179 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001181 This option makes sure that all symbols are loaded into the kernel
1182 image (i.e., symbols from all sections) in cost of increased kernel
1183 size (depending on the kernel configuration, it may be 300KiB or
1184 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001186 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001187
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001188config HOTPLUG
David Rientjes6a108a12011-01-20 14:44:16 -08001189 bool "Support for hot-pluggable devices" if EXPERT
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001190 default y
1191 help
1192 This option is provided for the case where no hotplug or uevent
1193 capabilities is wanted by the kernel. You should only consider
1194 disabling this option for embedded systems that do not use modules, a
1195 dynamic /dev tree, or dynamic device discovery. Just say Y.
1196
Matt Mackalld59745c2005-05-01 08:59:02 -07001197config PRINTK
1198 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001199 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001200 help
1201 This option enables normal printk support. Removing it
1202 eliminates most of the message strings from the kernel image
1203 and makes the kernel more or less silent. As this makes it
1204 very difficult to diagnose system problems, saying N here is
1205 strongly discouraged.
1206
Matt Mackallc8538a72005-05-01 08:59:01 -07001207config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001208 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001209 default y
1210 help
1211 Disabling this option eliminates support for BUG and WARN, reducing
1212 the size of your kernel image and potentially quietly ignoring
1213 numerous fatal conditions. You should only consider disabling this
1214 option for embedded systems with no facilities for reporting errors.
1215 Just say Y.
1216
Matt Mackall708e9a72006-01-08 01:05:25 -08001217config ELF_CORE
1218 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001219 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001220 help
1221 Enable support for generating core dumps. Disabling saves about 4k.
1222
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001223
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001224config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001225 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001226 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001227 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001228 default y
1229 help
1230 This option allows to disable the internal PC-Speaker
1231 support, saving some memory.
1232
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001233config HAVE_PCSPKR_PLATFORM
1234 bool
1235
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236config BASE_FULL
1237 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001238 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 help
1240 Disabling this option reduces the size of miscellaneous core
1241 kernel data structures. This saves memory on small machines,
1242 but may reduce performance.
1243
1244config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001245 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001247 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 help
1249 Disabling this option will cause the kernel to be built without
1250 support for "fast userspace mutexes". The resulting kernel may not
1251 run glibc-based applications correctly.
1252
1253config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001254 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001256 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 help
1258 Disabling this option will cause the kernel to be built without
1259 support for epoll family of system calls.
1260
Davide Libenzifba2afa2007-05-10 22:23:13 -07001261config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001262 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001263 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001264 default y
1265 help
1266 Enable the signalfd() system call that allows to receive signals
1267 on a file descriptor.
1268
1269 If unsure, say Y.
1270
Davide Libenzib215e282007-05-10 22:23:16 -07001271config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001272 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001273 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001274 default y
1275 help
1276 Enable the timerfd() system call that allows to receive timer
1277 events on a file descriptor.
1278
1279 If unsure, say Y.
1280
Davide Libenzie1ad7462007-05-10 22:23:19 -07001281config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001282 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001283 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001284 default y
1285 help
1286 Enable the eventfd() system call that allows to receive both
1287 kernel notification (ie. KAIO) or userspace notifications.
1288
1289 If unsure, say Y.
1290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001292 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 default y
1294 depends on MMU
1295 help
1296 The shmem is an internal filesystem used to manage shared memory.
1297 It is backed by swap and manages resource limits. It is also exported
1298 to userspace as tmpfs if TMPFS is enabled. Disabling this
1299 option replaces shmem and tmpfs with the much simpler ramfs code,
1300 which may be appropriate on small systems without swap.
1301
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001302config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001303 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001304 default y
1305 help
1306 This option enables POSIX asynchronous I/O which may by used
1307 by some high performance threaded applications. Disabling
1308 this option saves about 7k.
1309
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001310config EMBEDDED
1311 bool "Embedded system"
1312 select EXPERT
1313 help
1314 This option should be enabled if compiling the kernel for
1315 an embedded system so certain expert options are available
1316 for configuration.
1317
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001318config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001319 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001320 help
1321 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001322
Peter Zijlstra906010b2009-09-21 16:08:49 +02001323config PERF_USE_VMALLOC
1324 bool
1325 help
1326 See tools/perf/design.txt for details
1327
Ingo Molnar57c0c152009-09-21 12:20:38 +02001328menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001329
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001330config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001331 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001332 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001333 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001334 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001335 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001336 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001337 Enable kernel support for various performance events provided
1338 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001339
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001340 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001341 use of generic tracepoints.
1342
1343 Most modern CPUs support performance events via performance
1344 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001345 types of hw events: such as instructions executed, cachemisses
1346 suffered, or branches mis-predicted - without slowing down the
1347 kernel or applications. These registers can also trigger interrupts
1348 when a threshold number of events have passed - and can thus be
1349 used to profile the code that runs on that CPU.
1350
Ingo Molnar57c0c152009-09-21 12:20:38 +02001351 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001352 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001353 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001354 provides per task and per CPU counters, and it provides event
1355 capabilities on top of those.
1356
1357 Say Y if unsure.
1358
Peter Zijlstra906010b2009-09-21 16:08:49 +02001359config DEBUG_PERF_USE_VMALLOC
1360 default n
1361 bool "Debug: use vmalloc to back perf mmap() buffers"
1362 depends on PERF_EVENTS && DEBUG_KERNEL
1363 select PERF_USE_VMALLOC
1364 help
1365 Use vmalloc memory to back perf mmap() buffers.
1366
1367 Mostly useful for debugging the vmalloc code on platforms
1368 that don't require it.
1369
1370 Say N if unsure.
1371
Thomas Gleixner0793a612008-12-04 20:12:29 +01001372endmenu
1373
Christoph Lameterf8891e52006-06-30 01:55:45 -07001374config VM_EVENT_COUNTERS
1375 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001376 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001377 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001378 VM event counters are needed for event counts to be shown.
1379 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001380 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001381 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001382
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001383config PCI_QUIRKS
1384 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001385 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001386 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001387 help
1388 This enables workarounds for various PCI chipset
1389 bugs/quirks. Disable this only if your target machine is
1390 unaffected by PCI quirks.
1391
Christoph Lameter41ecc552007-05-09 02:32:44 -07001392config SLUB_DEBUG
1393 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001394 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001395 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001396 help
1397 SLUB has extensive debug support features. Disabling these can
1398 result in significant savings in code size. This also disables
1399 SLUB sysfs support. /sys/slab will not exist and there will be
1400 no support for cache validation etc.
1401
Randy Dunlapb943c462009-03-10 12:55:46 -07001402config COMPAT_BRK
1403 bool "Disable heap randomization"
1404 default y
1405 help
1406 Randomizing heap placement makes heap exploits harder, but it
1407 also breaks ancient binaries (including anything libc5 based).
1408 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001409 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001410 /proc/sys/kernel/randomize_va_space to 2.
1411
1412 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1413
Christoph Lameter81819f02007-05-06 14:49:36 -07001414choice
1415 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001416 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001417 help
1418 This option allows to select a slab allocator.
1419
1420config SLAB
1421 bool "SLAB"
1422 help
1423 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001424 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001425 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001426
1427config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001428 bool "SLUB (Unqueued Allocator)"
1429 help
1430 SLUB is a slab allocator that minimizes cache line usage
1431 instead of managing queues of cached objects (SLAB approach).
1432 Per cpu caching is realized using slabs of objects instead
1433 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001434 and has enhanced diagnostics. SLUB is the default choice for
1435 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001436
1437config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001438 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001439 bool "SLOB (Simple Allocator)"
1440 help
Matt Mackall37291452008-02-04 22:29:38 -08001441 SLOB replaces the stock allocator with a drastically simpler
1442 allocator. SLOB is generally more space efficient but
1443 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001444
1445endchoice
1446
Jie Zhangea637632009-12-14 18:00:02 -08001447config MMAP_ALLOW_UNINITIALIZED
1448 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001449 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001450 default n
1451 help
1452 Normally, and according to the Linux spec, anonymous memory obtained
1453 from mmap() has it's contents cleared before it is passed to
1454 userspace. Enabling this config option allows you to request that
1455 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1456 providing a huge performance boost. If this option is not enabled,
1457 then the flag will be ignored.
1458
1459 This is taken advantage of by uClibc's malloc(), and also by
1460 ELF-FDPIC binfmt's brk and stack allocator.
1461
1462 Because of the obvious security issues, this option should only be
1463 enabled on embedded devices where you control what is run in
1464 userspace. Since that isn't generally a problem on no-MMU systems,
1465 it is normally safe to say Y here.
1466
1467 See Documentation/nommu-mmap.txt for more information.
1468
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001469config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001470 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001471 help
1472 Say Y here to enable the extended profiling support mechanisms used
1473 by profilers such as OProfile.
1474
Ingo Molnar5f87f112008-07-23 14:15:22 +02001475#
1476# Place an empty function call at each tracepoint site. Can be
1477# dynamically changed for a probe function.
1478#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001479config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001480 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001481
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001482source "arch/Kconfig"
1483
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484endmenu # General setup
1485
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001486config HAVE_GENERIC_DMA_COHERENT
1487 bool
1488 default n
1489
Linus Torvalds158a9622008-01-02 13:04:48 -08001490config SLABINFO
1491 bool
1492 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001493 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001494 default y
1495
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001496config RT_MUTEXES
1497 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001498
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499config BASE_SMALL
1500 int
1501 default 0 if BASE_FULL
1502 default 1 if !BASE_FULL
1503
Jan Engelhardt66da5732007-07-15 23:39:29 -07001504menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 bool "Enable loadable module support"
1506 help
1507 Kernel modules are small pieces of compiled code which can
1508 be inserted in the running kernel, rather than being
1509 permanently built into the kernel. You use the "modprobe"
1510 tool to add (and sometimes remove) them. If you say Y here,
1511 many parts of the kernel can be built as modules (by
1512 answering M instead of Y where indicated): this is most
1513 useful for infrequently used options which are not required
1514 for booting. For more information, see the man pages for
1515 modprobe, lsmod, modinfo, insmod and rmmod.
1516
1517 If you say Y here, you will need to run "make
1518 modules_install" to put the modules under /lib/modules/
1519 where modprobe can find them (you may need to be root to do
1520 this).
1521
1522 If unsure, say Y.
1523
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001524if MODULES
1525
Linus Torvalds826e4502008-05-04 17:04:16 -07001526config MODULE_FORCE_LOAD
1527 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001528 default n
1529 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001530 Allow loading of modules without version information (ie. modprobe
1531 --force). Forced module loading sets the 'F' (forced) taint flag and
1532 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001533
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534config MODULE_UNLOAD
1535 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 help
1537 Without this option you will not be able to unload any
1538 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001539 anyway), which makes your kernel smaller, faster
1540 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541
1542config MODULE_FORCE_UNLOAD
1543 bool "Forced module unloading"
1544 depends on MODULE_UNLOAD && EXPERIMENTAL
1545 help
1546 This option allows you to force a module to unload, even if the
1547 kernel believes it is unsafe: the kernel will remove the module
1548 without waiting for anyone to stop using it (using the -f option to
1549 rmmod). This is mainly for kernel developers and desperate users.
1550 If unsure, say N.
1551
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001553 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 help
1555 Usually, you have to use modules compiled with your kernel.
1556 Saying Y here makes it sometimes possible to use modules
1557 compiled for different kernels, by adding enough information
1558 to the modules to (hopefully) spot any changes which would
1559 make them incompatible with the kernel you are running. If
1560 unsure, say N.
1561
1562config MODULE_SRCVERSION_ALL
1563 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564 help
1565 Modules which contain a MODULE_VERSION get an extra "srcversion"
1566 field inserted into their modinfo section, which contains a
1567 sum of the source files which made it. This helps maintainers
1568 see exactly which source was used to build a module (since
1569 others sometimes change the module source without updating
1570 the version). With this option, such a "srcversion" field
1571 will be created for all modules. If unsure, say N.
1572
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001573endif # MODULES
1574
Rusty Russell98a79d62008-12-13 21:19:41 +10301575config INIT_ALL_POSSIBLE
1576 bool
1577 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301578 Back when each arch used to define their own cpu_online_mask and
1579 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301580 with all 1s, and others with all 0s. When they were centralised,
1581 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001582 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301583
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584config STOP_MACHINE
1585 bool
1586 default y
1587 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1588 help
1589 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001590
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001591source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001592
1593config PREEMPT_NOTIFIERS
1594 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001595
Steffen Klassert16295be2010-01-06 19:47:10 +11001596config PADATA
1597 depends on SMP
1598 bool
1599
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001600source "kernel/Kconfig.locks"