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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 IRQ_WORK
24 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +080025
David Daney1dbdc6f2012-04-19 14:59:57 -070026config BUILDTIME_EXTABLE_SORT
27 bool
28
Al Boldiff0cfc62007-07-31 00:39:23 -070029menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31config EXPERIMENTAL
32 bool "Prompt for development and/or incomplete code/drivers"
33 ---help---
34 Some of the various things that Linux supports (such as network
35 drivers, file systems, network protocols, etc.) can be in a state
36 of development where the functionality, stability, or the level of
37 testing is not yet high enough for general use. This is usually
38 known as the "alpha-test" phase among developers. If a feature is
39 currently in alpha-test, then the developers usually discourage
40 uninformed widespread use of this feature by the general public to
41 avoid "Why doesn't this work?" type mail messages. However, active
42 testing and use of these systems is welcomed. Just be aware that it
43 may not meet the normal level of reliability or it may fail to work
44 in some special cases. Detailed bug reports from people familiar
45 with the kernel internals are usually welcomed by the developers
46 (before submitting bug reports, please read the documents
47 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
48 <file:Documentation/BUG-HUNTING>, and
49 <file:Documentation/oops-tracing.txt> in the kernel source).
50
51 This option will also make obsoleted drivers available. These are
52 drivers that have been replaced by something else, and/or are
53 scheduled to be removed in a future kernel release.
54
55 Unless you intend to help test and develop a feature or driver that
56 falls into this category, or you have a situation that requires
57 using these features, you should probably say N here, which will
58 cause the configurator to present you with fewer choices. If
59 you say Y here, you will be offered the choice of using features or
60 drivers that are currently considered to be in the alpha-test phase.
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062config BROKEN
63 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65config BROKEN_ON_SMP
66 bool
67 depends on BROKEN || !SMP
68 default y
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070config INIT_ENV_ARG_LIMIT
71 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070072 default 32 if !UML
73 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080075 Maximum of each of the number of arguments and environment
76 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Roland McGrath84336462009-12-21 16:24:06 -080079config CROSS_COMPILE
80 string "Cross-compiler tool prefix"
81 help
82 Same as running 'make CROSS_COMPILE=prefix-' but stored for
83 default make runs in this kernel build directory. You don't
84 need to set this unless you want the configured kernel build
85 directory to select the cross-compiler automatically.
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087config LOCALVERSION
88 string "Local version - append to kernel release"
89 help
90 Append an extra string to the end of your kernel version.
91 This will show up when you type uname, for example.
92 The string you set here will be appended after the contents of
93 any files with a filename matching localversion* in your
94 object and source tree, in that order. Your total string can
95 be a maximum of 64 characters.
96
Ryan Andersonaaebf432005-07-31 04:57:49 -040097config LOCALVERSION_AUTO
98 bool "Automatically append version information to the version string"
99 default y
100 help
101 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200102 release tree by looking for git tags that belong to the current
103 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400104
105 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400107 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200108 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400109
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 (The actual string used here is the first eight characters produced
111 by running the command:
112
113 $ git rev-parse --verify HEAD
114
115 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400116
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800117config HAVE_KERNEL_GZIP
118 bool
119
120config HAVE_KERNEL_BZIP2
121 bool
122
123config HAVE_KERNEL_LZMA
124 bool
125
Lasse Collin3ebe1242011-01-12 17:01:23 -0800126config HAVE_KERNEL_XZ
127 bool
128
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800129config HAVE_KERNEL_LZO
130 bool
131
Alain Knaff30d65db2009-01-04 22:46:17 +0100132choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800133 prompt "Kernel compression mode"
134 default KERNEL_GZIP
Lasse Collin3ebe1242011-01-12 17:01:23 -0800135 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 -0800136 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100137 The linux kernel is a kind of self-extracting executable.
138 Several compression algorithms are available, which differ
139 in efficiency, compression and decompression speed.
140 Compression speed is only relevant when building a kernel.
141 Decompression speed is relevant at each boot.
142
143 If you have any problems with bzip2 or lzma compressed
144 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
145 version of this functionality (bzip2 only), for 2.4, was
146 supplied by Christian Ludwig)
147
148 High compression options are mostly useful for users, who
149 are low on disk space (embedded systems), but for whom ram
150 size matters less.
151
152 If in doubt, select 'gzip'
153
154config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800155 bool "Gzip"
156 depends on HAVE_KERNEL_GZIP
157 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800158 The old and tried gzip compression. It provides a good balance
159 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100160
161config KERNEL_BZIP2
162 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800163 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100164 help
165 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700166 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800167 size is about 10% smaller with bzip2, in comparison to gzip.
168 Bzip2 uses a large amount of memory. For modern kernels you
169 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100170
171config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800172 bool "LZMA"
173 depends on HAVE_KERNEL_LZMA
174 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700175 This compression algorithm's ratio is best. Decompression speed
176 is between gzip and bzip2. Compression is slowest.
177 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100178
Lasse Collin3ebe1242011-01-12 17:01:23 -0800179config KERNEL_XZ
180 bool "XZ"
181 depends on HAVE_KERNEL_XZ
182 help
183 XZ uses the LZMA2 algorithm and instruction set specific
184 BCJ filters which can improve compression ratio of executable
185 code. The size of the kernel is about 30% smaller with XZ in
186 comparison to gzip. On architectures for which there is a BCJ
187 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
188 will create a few percent smaller kernel than plain LZMA.
189
190 The speed is about the same as with LZMA: The decompression
191 speed of XZ is better than that of bzip2 but worse than gzip
192 and LZO. Compression is slow.
193
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800194config KERNEL_LZO
195 bool "LZO"
196 depends on HAVE_KERNEL_LZO
197 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700198 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200199 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800200 (both compression and decompression) is the fastest.
201
Alain Knaff30d65db2009-01-04 22:46:17 +0100202endchoice
203
Josh Triplettbd5dc172011-06-15 15:08:28 -0700204config DEFAULT_HOSTNAME
205 string "Default hostname"
206 default "(none)"
207 help
208 This option determines the default system hostname before userspace
209 calls sethostname(2). The kernel traditionally uses "(none)" here,
210 but you may wish to use a different default here to make a minimal
211 system more usable with less configuration.
212
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213config SWAP
214 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200215 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 default y
217 help
218 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100219 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 used to provide more virtual memory than the actual RAM present
221 in your computer. If unsure say Y.
222
223config SYSVIPC
224 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 ---help---
226 Inter Process Communication is a suite of library functions and
227 system calls which let processes (running programs) synchronize and
228 exchange information. It is generally considered to be a good thing,
229 and some programs won't run unless you say Y here. In particular, if
230 you want to run the DOS emulator dosemu under Linux (read the
231 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
232 you'll need to say Y here.
233
234 You can find documentation about IPC with "info ipc" and also in
235 section 6.4 of the Linux Programmer's Guide, available from
236 <http://www.tldp.org/guides.html>.
237
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800238config SYSVIPC_SYSCTL
239 bool
240 depends on SYSVIPC
241 depends on SYSCTL
242 default y
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244config POSIX_MQUEUE
245 bool "POSIX Message Queues"
246 depends on NET && EXPERIMENTAL
247 ---help---
248 POSIX variant of message queues is a part of IPC. In POSIX message
249 queues every message has a priority which decides about succession
250 of receiving it by a process. If you want to compile and run
251 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200252 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 POSIX message queues are visible as a filesystem called 'mqueue'
255 and can be mounted somewhere if you want to do filesystem
256 operations on message queues.
257
258 If unsure, say Y.
259
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700260config POSIX_MQUEUE_SYSCTL
261 bool
262 depends on POSIX_MQUEUE
263 depends on SYSCTL
264 default y
265
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530266config FHANDLE
267 bool "open by fhandle syscalls"
268 select EXPORTFS
269 help
270 If you say Y here, a user level program will be able to map
271 file names to handle and then later use the handle for
272 different file system operations. This is useful in implementing
273 userspace file servers, which now track files using handles instead
274 of names. The handle would remain the same even if file names
275 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
276 syscalls.
277
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278config AUDIT
279 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100280 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 help
282 Enable auditing infrastructure that can be used with another
283 kernel subsystem, such as SELinux (which requires this for
284 logging of avc messages output). Does not do system-call
285 auditing without CONFIG_AUDITSYSCALL.
286
287config AUDITSYSCALL
288 bool "Enable system-call auditing support"
Will Deacon8f827a12012-07-06 15:48:16 +0100289 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 default y if SECURITY_SELINUX
291 help
292 Enable low-overhead system-call auditing infrastructure that
293 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500294 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
Eric Paris939a67f2009-12-17 20:12:06 -0500296config AUDIT_WATCH
297 def_bool y
298 depends on AUDITSYSCALL
299 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
Al Viro74c3cbe2007-07-22 08:04:18 -0400301config AUDIT_TREE
302 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400303 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500304 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400305
Eric Paris633b4542012-01-03 14:23:08 -0500306config AUDIT_LOGINUID_IMMUTABLE
307 bool "Make audit loginuid immutable"
308 depends on AUDIT
309 help
Linus Torvaldsf429ee32012-01-17 16:06:51 -0800310 The config option toggles if a task setting its loginuid requires
Eric Paris633b4542012-01-03 14:23:08 -0500311 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
312 but should instead only allow setting its loginuid if it was never
313 previously set. On systems which use systemd or a similar central
314 process to restart login services this should be set to true. On older
315 systems in which an admin would typically have to directly stop and
316 start processes this should be set to false. Setting this to true allows
317 one to drop potentially dangerous capabilites from the login tasks,
318 but may not be backwards compatible with older init systems.
319
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000320source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200321source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000322
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200323menu "CPU/Task time and stats accounting"
324
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200325config VIRT_CPU_ACCOUNTING
326 bool
327
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200328choice
329 prompt "Cputime accounting"
330 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100331 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200332
333# Kind of a stub config for the pure tick based cputime accounting
334config TICK_CPU_ACCOUNTING
335 bool "Simple tick based cputime accounting"
336 depends on !S390
337 help
338 This is the basic tick based cputime accounting that maintains
339 statistics about user, system and idle time spent on per jiffies
340 granularity.
341
342 If unsure, say Y.
343
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200344config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200345 bool "Deterministic task and CPU time accounting"
346 depends on HAVE_VIRT_CPU_ACCOUNTING
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200347 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200348 help
349 Select this option to enable more accurate task and CPU time
350 accounting. This is done by reading a CPU counter on each
351 kernel entry and exit and on transitions within the kernel
352 between system, softirq and hardirq state, so there is a
353 small performance impact. In the case of s390 or IBM POWER > 5,
354 this also enables accounting of stolen time on logically-partitioned
355 systems.
356
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200357config VIRT_CPU_ACCOUNTING_GEN
358 bool "Full dynticks CPU time accounting"
359 depends on HAVE_CONTEXT_TRACKING && 64BIT
360 select VIRT_CPU_ACCOUNTING
361 select CONTEXT_TRACKING
362 help
363 Select this option to enable task and CPU time accounting on full
364 dynticks systems. This accounting is implemented by watching every
365 kernel-user boundaries using the context tracking subsystem.
366 The accounting is thus performed at the expense of some significant
367 overhead.
368
369 For now this is only useful if you are working on the full
370 dynticks subsystem development.
371
372 If unsure, say N.
373
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200374config IRQ_TIME_ACCOUNTING
375 bool "Fine granularity task level IRQ time accounting"
376 depends on HAVE_IRQ_TIME_ACCOUNTING
377 help
378 Select this option to enable fine granularity task irq time
379 accounting. This is done by reading a timestamp on each
380 transitions between softirq and hardirq state, so there can be a
381 small performance impact.
382
383 If in doubt, say N here.
384
385endchoice
386
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200387config BSD_PROCESS_ACCT
388 bool "BSD Process Accounting"
389 help
390 If you say Y here, a user level program will be able to instruct the
391 kernel (via a special system call) to write process accounting
392 information to a file: whenever a process exits, information about
393 that process will be appended to the file by the kernel. The
394 information includes things such as creation time, owning user,
395 command name, memory usage, controlling terminal etc. (the complete
396 list is in the struct acct in <file:include/linux/acct.h>). It is
397 up to the user level program to do useful things with this
398 information. This is generally a good idea, so say Y.
399
400config BSD_PROCESS_ACCT_V3
401 bool "BSD Process Accounting version 3 file format"
402 depends on BSD_PROCESS_ACCT
403 default n
404 help
405 If you say Y here, the process accounting information is written
406 in a new file format that also logs the process IDs of each
407 process and it's parent. Note that this file format is incompatible
408 with previous v0/v1/v2 file formats, so you will need updated tools
409 for processing it. A preliminary version of these tools is available
410 at <http://www.gnu.org/software/acct/>.
411
412config TASKSTATS
413 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
414 depends on NET
415 default n
416 help
417 Export selected statistics for tasks/processes through the
418 generic netlink interface. Unlike BSD process accounting, the
419 statistics are available during the lifetime of tasks/processes as
420 responses to commands. Like BSD accounting, they are sent to user
421 space on task exit.
422
423 Say N if unsure.
424
425config TASK_DELAY_ACCT
426 bool "Enable per-task delay accounting (EXPERIMENTAL)"
427 depends on TASKSTATS
428 help
429 Collect information on time spent by a task waiting for system
430 resources like cpu, synchronous block I/O completion and swapping
431 in pages. Such statistics can help in setting a task's priorities
432 relative to other tasks for cpu, io, rss limits etc.
433
434 Say N if unsure.
435
436config TASK_XACCT
437 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
438 depends on TASKSTATS
439 help
440 Collect extended task accounting data and send the data
441 to userland for processing over the taskstats interface.
442
443 Say N if unsure.
444
445config TASK_IO_ACCOUNTING
446 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
447 depends on TASK_XACCT
448 help
449 Collect information on the number of bytes of storage I/O which this
450 task has caused.
451
452 Say N if unsure.
453
454endmenu # "CPU/Task time and stats accounting"
455
Mike Travisc903ff82009-01-15 12:28:29 -0800456menu "RCU Subsystem"
457
458choice
459 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700460 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800461
Mike Travisc903ff82009-01-15 12:28:29 -0800462config TREE_RCU
463 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700464 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800465 help
466 This option selects the RCU implementation that is
467 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700468 thousands of CPUs. It also scales down nicely to
469 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800470
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700471config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700472 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800473 depends on PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700474 help
475 This option selects the RCU implementation that is
476 designed for very large SMP systems with hundreds or
477 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700478 is also required. It also scales down nicely to
479 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700480
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800481 Select this option if you are unsure.
482
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700483config TINY_RCU
484 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700485 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700486 help
487 This option selects the RCU implementation that is
488 designed for UP systems from which real-time response
489 is not required. This option greatly reduces the
490 memory footprint of RCU.
491
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700492config TINY_PREEMPT_RCU
493 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700494 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700495 help
496 This option selects the RCU implementation that is designed
497 for real-time UP systems. This option greatly reduces the
498 memory footprint of RCU.
499
Mike Travisc903ff82009-01-15 12:28:29 -0800500endchoice
501
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700502config PREEMPT_RCU
503 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
504 help
505 This option enables preemptible-RCU code that is common between
506 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
507
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700508config RCU_STALL_COMMON
509 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
510 help
511 This option enables RCU CPU stall code that is common between
512 the TINY and TREE variants of RCU. The purpose is to allow
513 the tiny variants to disable RCU CPU stall warnings, while
514 making these warnings mandatory for the tree variants.
515
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100516config CONTEXT_TRACKING
517 bool
518
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200519config RCU_USER_QS
520 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100521 depends on HAVE_CONTEXT_TRACKING && SMP
522 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200523 help
524 This option sets hooks on kernel / userspace boundaries and
525 puts RCU in extended quiescent state when the CPU runs in
526 userspace. It means that when a CPU runs in userspace, it is
527 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700528 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200529
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200530 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100531 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700532 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200533
534 If unsure say N
535
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100536config CONTEXT_TRACKING_FORCE
537 bool "Force context tracking"
538 depends on CONTEXT_TRACKING
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200539 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100540 Probe on user/kernel boundaries by default in order to
541 test the features that rely on it such as userspace RCU extended
542 quiescent states.
543 This test is there for debugging until we have a real user like the
544 full dynticks mode.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200545
Mike Travisc903ff82009-01-15 12:28:29 -0800546config RCU_FANOUT
547 int "Tree-based hierarchical RCU fanout value"
548 range 2 64 if 64BIT
549 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700550 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800551 default 64 if 64BIT
552 default 32 if !64BIT
553 help
554 This option controls the fanout of hierarchical implementations
555 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700556 large numbers of CPUs. This value must be at least the fourth
557 root of NR_CPUS, which allows NR_CPUS to be insanely large.
558 The default value of RCU_FANOUT should be used for production
559 systems, but if you are stress-testing the RCU implementation
560 itself, small RCU_FANOUT values allow you to test large-system
561 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800562
563 Select a specific number if testing RCU itself.
564 Take the default if unsure.
565
Paul E. McKenney8932a632012-04-19 12:20:14 -0700566config RCU_FANOUT_LEAF
567 int "Tree-based hierarchical RCU leaf-level fanout value"
568 range 2 RCU_FANOUT if 64BIT
569 range 2 RCU_FANOUT if !64BIT
570 depends on TREE_RCU || TREE_PREEMPT_RCU
571 default 16
572 help
573 This option controls the leaf-level fanout of hierarchical
574 implementations of RCU, and allows trading off cache misses
575 against lock contention. Systems that synchronize their
576 scheduling-clock interrupts for energy-efficiency reasons will
577 want the default because the smaller leaf-level fanout keeps
578 lock contention levels acceptably low. Very large systems
579 (hundreds or thousands of CPUs) will instead want to set this
580 value to the maximum value possible in order to reduce the
581 number of cache misses incurred during RCU's grace-period
582 initialization. These systems tend to run CPU-bound, and thus
583 are not helped by synchronized interrupts, and thus tend to
584 skew them, which reduces lock contention enough that large
585 leaf-level fanouts work well.
586
587 Select a specific number if testing RCU itself.
588
589 Select the maximum permissible value for large systems.
590
591 Take the default if unsure.
592
Mike Travisc903ff82009-01-15 12:28:29 -0800593config RCU_FANOUT_EXACT
594 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700595 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800596 default n
597 help
598 This option forces use of the exact RCU_FANOUT value specified,
599 regardless of imbalances in the hierarchy. This is useful for
600 testing RCU itself, and might one day be useful on systems with
601 strong NUMA behavior.
602
603 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
604
605 Say N if unsure.
606
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800607config RCU_FAST_NO_HZ
608 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700609 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800610 default n
611 help
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700612 This option causes RCU to attempt to accelerate grace periods in
613 order to allow CPUs to enter dynticks-idle state more quickly.
614 On the other hand, this option increases the overhead of the
615 dynticks-idle checking, thus degrading scheduling latency.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800616
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700617 Say Y if energy efficiency is critically important, and you don't
618 care about real-time response.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800619
620 Say N if you are unsure.
621
Mike Travisc903ff82009-01-15 12:28:29 -0800622config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700623 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800624 select DEBUG_FS
625 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700626 This option provides tracing for the TREE_RCU and
627 TREE_PREEMPT_RCU implementations, permitting Makefile to
628 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800629
Paul E. McKenney24278d12010-09-27 17:25:23 -0700630config RCU_BOOST
631 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800632 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700633 default n
634 help
635 This option boosts the priority of preempted RCU readers that
636 block the current preemptible RCU grace period for too long.
637 This option also prevents heavy loads from blocking RCU
638 callback invocation for all flavors of RCU.
639
640 Say Y here if you are working with real-time apps or heavy loads
641 Say N here if you are unsure.
642
643config RCU_BOOST_PRIO
644 int "Real-time priority to boost RCU readers to"
645 range 1 99
646 depends on RCU_BOOST
647 default 1
648 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700649 This option specifies the real-time priority to which long-term
650 preempted RCU readers are to be boosted. If you are working
651 with a real-time application that has one or more CPU-bound
652 threads running at a real-time priority level, you should set
653 RCU_BOOST_PRIO to a priority higher then the highest-priority
654 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
655 of 1 is appropriate in the common case, which is real-time
656 applications that do not have any CPU-bound threads.
657
658 Some real-time applications might not have a single real-time
659 thread that saturates a given CPU, but instead might have
660 multiple real-time threads that, taken together, fully utilize
661 that CPU. In this case, you should set RCU_BOOST_PRIO to
662 a priority higher than the lowest-priority thread that is
663 conspiring to prevent the CPU from running any non-real-time
664 tasks. For example, if one thread at priority 10 and another
665 thread at priority 5 are between themselves fully consuming
666 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
667 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700668
669 Specify the real-time priority, or take the default if unsure.
670
671config RCU_BOOST_DELAY
672 int "Milliseconds to delay boosting after RCU grace-period start"
673 range 0 3000
674 depends on RCU_BOOST
675 default 500
676 help
677 This option specifies the time to wait after the beginning of
678 a given grace period before priority-boosting preempted RCU
679 readers blocking that grace period. Note that any RCU reader
680 blocking an expedited RCU grace period is boosted immediately.
681
682 Accept the default if unsure.
683
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700684config RCU_NOCB_CPU
685 bool "Offload RCU callback processing from boot-selected CPUs"
686 depends on TREE_RCU || TREE_PREEMPT_RCU
687 default n
688 help
689 Use this option to reduce OS jitter for aggressive HPC or
690 real-time workloads. It can also be used to offload RCU
691 callback invocation to energy-efficient CPUs in battery-powered
692 asymmetric multiprocessors.
693
694 This option offloads callback invocation from the set of
695 CPUs specified at boot time by the rcu_nocbs parameter.
696 For each such CPU, a kthread ("rcuoN") will be created to
697 invoke callbacks, where the "N" is the CPU being offloaded.
698 Nothing prevents this kthread from running on the specified
699 CPUs, but (1) the kthreads may be preempted between each
700 callback, and (2) affinity or cgroups can be used to force
701 the kthreads to run on whatever set of CPUs is desired.
702
703 Say Y here if you want reduced OS jitter on selected CPUs.
704 Say N here if you are unsure.
705
Mike Travisc903ff82009-01-15 12:28:29 -0800706endmenu # "RCU Subsystem"
707
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700709 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 ---help---
711 This option enables the complete Linux kernel ".config" file
712 contents to be saved in the kernel. It provides documentation
713 of which kernel options are used in a running kernel or in an
714 on-disk kernel. This information can be extracted from the kernel
715 image file with the script scripts/extract-ikconfig and used as
716 input to rebuild the current kernel or to build another kernel.
717 It can also be extracted from a running kernel by reading
718 /proc/config.gz if enabled (below).
719
720config IKCONFIG_PROC
721 bool "Enable access to .config through /proc/config.gz"
722 depends on IKCONFIG && PROC_FS
723 ---help---
724 This option enables access to the kernel configuration file
725 through /proc/config.gz.
726
Alistair John Strachan794543a2007-05-08 00:31:15 -0700727config LOG_BUF_SHIFT
728 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
729 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700730 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700731 help
732 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700733 Examples:
734 17 => 128 KB
735 16 => 64 KB
736 15 => 32 KB
737 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700738 13 => 8 KB
739 12 => 4 KB
740
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800741#
742# Architectures with an unreliable sched_clock() should select this:
743#
744config HAVE_UNSTABLE_SCHED_CLOCK
745 bool
746
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200747#
748# For architectures that want to enable the support for NUMA-affine scheduler
749# balancing logic:
750#
751config ARCH_SUPPORTS_NUMA_BALANCING
752 bool
753
754# For architectures that (ab)use NUMA to represent different memory regions
755# all cpu-local but of different latencies, such as SuperH.
756#
757config ARCH_WANT_NUMA_VARIABLE_LOCALITY
758 bool
759
760#
761# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
762config ARCH_WANTS_PROT_NUMA_PROT_NONE
763 bool
764
765config ARCH_USES_NUMA_PROT_NONE
766 bool
767 default y
768 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
769 depends on NUMA_BALANCING
770
Mel Gorman1a687c22012-11-22 11:16:36 +0000771config NUMA_BALANCING_DEFAULT_ENABLED
772 bool "Automatically enable NUMA aware memory/task placement"
773 default y
774 depends on NUMA_BALANCING
775 help
776 If set, autonumic NUMA balancing will be enabled if running on a NUMA
777 machine.
778
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200779config NUMA_BALANCING
780 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200781 depends on ARCH_SUPPORTS_NUMA_BALANCING
782 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
783 depends on SMP && NUMA && MIGRATION
784 help
785 This option adds support for automatic NUMA aware memory/task placement.
786 The mechanism is quite primitive and is based on migrating memory when
787 it is references to the node the task is running on.
788
789 This system will be inactive on UMA systems.
790
Li Zefan23964d22009-01-15 13:50:58 -0800791menuconfig CGROUPS
792 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800793 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700794 help
Li Zefan23964d22009-01-15 13:50:58 -0800795 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800796 use with process control subsystems such as Cpusets, CFS, memory
797 controls or device isolation.
798 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800799 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800800 - Documentation/cgroups/ (features for grouping, isolation
801 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700802
803 Say N if unsure.
804
Li Zefan23964d22009-01-15 13:50:58 -0800805if CGROUPS
806
Paul Menage006cb992007-10-18 23:39:43 -0700807config CGROUP_DEBUG
808 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700809 default n
Paul Menage006cb992007-10-18 23:39:43 -0700810 help
811 This option enables a simple cgroup subsystem that
812 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800813 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700814
Li Zefan23964d22009-01-15 13:50:58 -0800815 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700816
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700817config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800818 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800819 help
820 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700821 cgroup.
822
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700823config CGROUP_DEVICE
824 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700825 help
826 Provides a cgroup implementing whitelists for devices which
827 a process in the cgroup can mknod or open.
828
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829config CPUSETS
830 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700832 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 allow dynamically partitioning a system into sets of CPUs and
834 Memory Nodes and assigning tasks to run only within those sets.
835 This is primarily useful on large SMP or NUMA systems.
836
837 Say N if unsure.
838
Li Zefan23964d22009-01-15 13:50:58 -0800839config PROC_PID_CPUSET
840 bool "Include legacy /proc/<pid>/cpuset file"
841 depends on CPUSETS
842 default y
843
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100844config CGROUP_CPUACCT
845 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100846 help
847 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800848 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100849
Pavel Emelianove552b662008-02-07 00:13:49 -0800850config RESOURCE_COUNTERS
851 bool "Resource counters"
852 help
853 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800854 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800855
Andrew Mortonc255a452012-07-31 16:43:02 -0700856config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800857 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700858 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700859 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800860 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700861 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100862 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800863
864 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700865 associated with each page of memory in the system. By this,
866 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
867 usage tracking struct at boot. Total amount of this is printed out
868 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800869
870 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700871 sure you need the memory resource controller. Even when you enable
872 this, you can set "cgroup_disable=memory" at your boot option to
873 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800874 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800875
Balbir Singhcf475ad2008-04-29 01:00:16 -0700876 This config option also selects MM_OWNER config option, which
877 could in turn add some fork/exit overhead.
878
Andrew Mortonc255a452012-07-31 16:43:02 -0700879config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700880 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700881 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800882 help
883 Add swap management feature to memory resource controller. When you
884 enable this, you can limit mem+swap usage per cgroup. In other words,
885 when you disable this, memory resource controller has no cares to
886 usage of swap...a process can exhaust all of the swap. This extension
887 is useful when you want to avoid exhaustion swap but this itself
888 adds more overheads and consumes memory for remembering information.
889 Especially if you use 32bit system or small memory system, please
890 be careful about enabling this. When memory resource controller
891 is disabled by boot option, this will be automatically disabled and
892 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700893 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700894 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
895 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -0700896config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -0800897 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700898 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800899 default y
900 help
901 Memory Resource Controller Swap Extension comes with its price in
902 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700903 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800904 and let the user enable it by swapaccount boot command line
905 parameter should have this option unselected.
906 For those who want to have the feature enabled by default should
907 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700908 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700909config MEMCG_KMEM
Glauber Costae5671df2011-12-11 21:47:01 +0000910 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
Andrew Mortonc255a452012-07-31 16:43:02 -0700911 depends on MEMCG && EXPERIMENTAL
Glauber Costa510fc4e2012-12-18 14:21:47 -0800912 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +0000913 help
914 The Kernel Memory extension for Memory Resource Controller can limit
915 the amount of memory used by kernel objects in the system. Those are
916 fundamentally different from the entities handled by the standard
917 Memory Controller, which are page-based, and can be swapped. Users of
918 the kmem extension can use it to guarantee that no group of processes
919 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800920
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700921config CGROUP_HUGETLB
922 bool "HugeTLB Resource Controller for Control Groups"
923 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
924 default n
925 help
926 Provides a cgroup Resource Controller for HugeTLB pages.
927 When you enable this, you can put a per cgroup limit on HugeTLB usage.
928 The limit is enforced during page fault. Since HugeTLB doesn't
929 support page reclaim, enforcing the limit at page fault time implies
930 that, the application will get SIGBUS signal if it tries to access
931 HugeTLB pages beyond its limit. This requires the application to know
932 beforehand how much HugeTLB pages it would require for its use. The
933 control group is tracked in the third page lru pointer. This means
934 that we cannot use the controller with huge page less than 3 pages.
935
Stephane Eraniane5d13672011-02-14 11:20:01 +0200936config CGROUP_PERF
937 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
938 depends on PERF_EVENTS && CGROUPS
939 help
940 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800941 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200942 designated cpu.
943
944 Say N if unsure.
945
Dhaval Giani7c941432010-01-20 13:26:18 +0100946menuconfig CGROUP_SCHED
947 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100948 default n
949 help
950 This feature lets CPU scheduler recognize task groups and control CPU
951 bandwidth allocation to such task groups. It uses cgroups to group
952 tasks.
953
954if CGROUP_SCHED
955config FAIR_GROUP_SCHED
956 bool "Group scheduling for SCHED_OTHER"
957 depends on CGROUP_SCHED
958 default CGROUP_SCHED
959
Paul Turnerab84d312011-07-21 09:43:28 -0700960config CFS_BANDWIDTH
961 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
962 depends on EXPERIMENTAL
963 depends on FAIR_GROUP_SCHED
964 default n
965 help
966 This option allows users to define CPU bandwidth rates (limits) for
967 tasks running within the fair group scheduler. Groups with no limit
968 set are considered to be unconstrained and will run with no
969 restriction.
970 See tip/Documentation/scheduler/sched-bwc.txt for more information.
971
Dhaval Giani7c941432010-01-20 13:26:18 +0100972config RT_GROUP_SCHED
973 bool "Group scheduling for SCHED_RR/FIFO"
974 depends on EXPERIMENTAL
975 depends on CGROUP_SCHED
976 default n
977 help
978 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800979 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100980 schedule realtime tasks for non-root users until you allocate
981 realtime bandwidth for them.
982 See Documentation/scheduler/sched-rt-group.txt for more information.
983
984endif #CGROUP_SCHED
985
Vivek Goyalafc24d42010-04-26 19:27:56 +0200986config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -0800987 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700988 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200989 default n
990 ---help---
991 Generic block IO controller cgroup interface. This is the common
992 cgroup interface which should be used by various IO controlling
993 policies.
994
995 Currently, CFQ IO scheduler uses it to recognize task groups and
996 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400997 to such task groups. It is also used by bio throttling logic in
998 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200999
1000 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001001 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001002 enabling proportional weight division of disk bandwidth in CFQ, set
1003 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001004 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001005
1006 See Documentation/cgroups/blkio-controller.txt for more information.
1007
1008config DEBUG_BLK_CGROUP
1009 bool "Enable Block IO controller debugging"
1010 depends on BLK_CGROUP
1011 default n
1012 ---help---
1013 Enable some debugging help. Currently it exports additional stat
1014 files in a cgroup which can be useful for debugging.
1015
Li Zefan23964d22009-01-15 13:50:58 -08001016endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001017
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001018config CHECKPOINT_RESTORE
1019 bool "Checkpoint/restore support" if EXPERT
1020 default n
1021 help
1022 Enables additional kernel features in a sake of checkpoint/restore.
1023 In particular it adds auxiliary prctl codes to setup process text,
1024 data and heap segment sizes, and a few additional /proc filesystem
1025 entries.
1026
1027 If unsure, say N here.
1028
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001029menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001030 bool "Namespaces support" if EXPERT
1031 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001032 help
1033 Provides the way to make tasks work with different objects using
1034 the same id. For example same IPC id may refer to different objects
1035 or same user id or pid may refer to different tasks when used in
1036 different namespaces.
1037
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001038if NAMESPACES
1039
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001040config UTS_NS
1041 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001042 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001043 help
1044 In this namespace tasks see different info provided with the
1045 uname() system call
1046
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001047config IPC_NS
1048 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001049 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001050 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001051 help
1052 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001053 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001054
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001055config USER_NS
1056 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001057 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001058 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001059 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001060
Eric W. Biederman5673a942011-11-17 10:23:55 -08001061 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001062 help
1063 This allows containers, i.e. vservers, to use user namespaces
1064 to provide different user info for different servers.
1065 If unsure, say N.
1066
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001067config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001068 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001069 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001070 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001071 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001072 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001073 pid namespaces. This is a building block of containers.
1074
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001075config NET_NS
1076 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001077 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001078 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001079 help
1080 Allow user space to create what appear to be multiple instances
1081 of the network stack.
1082
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001083endif # NAMESPACES
1084
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001085config UIDGID_CONVERTED
1086 # True if all of the selected software conmponents are known
1087 # to have uid_t and gid_t converted to kuid_t and kgid_t
1088 # where appropriate and are otherwise safe to use with
1089 # the user namespace.
1090 bool
1091 default y
1092
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001093 # Networking
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001094 depends on NET_9P = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001095
1096 # Filesystems
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001097 depends on 9P_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001098 depends on AFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001099 depends on CEPH_FS = n
1100 depends on CIFS = n
1101 depends on CODA_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001102 depends on GFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001103 depends on NCP_FS = n
1104 depends on NFSD = n
1105 depends on NFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001106 depends on OCFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001107 depends on XFS_FS = n
1108
Eric W. Biederman5673a942011-11-17 10:23:55 -08001109config UIDGID_STRICT_TYPE_CHECKS
1110 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001111 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001112 default n
1113 help
1114 While the nececessary conversions are being added to all subsystems this option allows
1115 the code to continue to build for unconverted subsystems.
1116
1117 Say Y here if you want the strict type checking enabled
1118
Mike Galbraith5091faa2010-11-30 14:18:03 +01001119config SCHED_AUTOGROUP
1120 bool "Automatic process group scheduling"
1121 select EVENTFD
1122 select CGROUPS
1123 select CGROUP_SCHED
1124 select FAIR_GROUP_SCHED
1125 help
1126 This option optimizes the scheduler for common desktop workloads by
1127 automatically creating and populating task groups. This separation
1128 of workloads isolates aggressive CPU burners (like build jobs) from
1129 desktop applications. Task group autogeneration is currently based
1130 upon task session.
1131
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001132config MM_OWNER
1133 bool
1134
1135config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001136 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001137 depends on SYSFS
1138 default n
1139 help
1140 This option adds code that switches the layout of the "block" class
1141 devices, to not show up in /sys/class/block/, but only in
1142 /sys/block/.
1143
1144 This switch is only active when the sysfs.deprecated=1 boot option is
1145 passed or the SYSFS_DEPRECATED_V2 option is set.
1146
1147 This option allows new kernels to run on old distributions and tools,
1148 which might get confused by /sys/class/block/. Since 2007/2008 all
1149 major distributions and tools handle this just fine.
1150
1151 Recent distributions and userspace tools after 2009/2010 depend on
1152 the existence of /sys/class/block/, and will not work with this
1153 option enabled.
1154
1155 Only if you are using a new kernel on an old distribution, you might
1156 need to say Y here.
1157
1158config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001159 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001160 default n
1161 depends on SYSFS
1162 depends on SYSFS_DEPRECATED
1163 help
1164 Enable deprecated sysfs by default.
1165
1166 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1167 option.
1168
1169 Only if you are using a new kernel on an old distribution, you might
1170 need to say Y here. Even then, odds are you would not need it
1171 enabled, you can always pass the boot option if absolutely necessary.
1172
1173config RELAY
1174 bool "Kernel->user space relay support (formerly relayfs)"
1175 help
1176 This option enables support for relay interface support in
1177 certain file systems (such as debugfs).
1178 It is designed to provide an efficient mechanism for tools and
1179 facilities to relay large amounts of data from kernel space to
1180 user space.
1181
1182 If unsure, say N.
1183
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001184config BLK_DEV_INITRD
1185 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1186 depends on BROKEN || !FRV
1187 help
1188 The initial RAM filesystem is a ramfs which is loaded by the
1189 boot loader (loadlin or lilo) and that is mounted as root
1190 before the normal boot procedure. It is typically used to
1191 load modules needed to mount the "real" root file system,
1192 etc. See <file:Documentation/initrd.txt> for details.
1193
1194 If RAM disk support (BLK_DEV_RAM) is also included, this
1195 also enables initial RAM disk (initrd) support and adds
1196 15 Kbytes (more on some other architectures) to the kernel size.
1197
1198 If unsure say Y.
1199
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001200if BLK_DEV_INITRD
1201
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001202source "usr/Kconfig"
1203
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001204endif
1205
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001206config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001207 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001208 help
1209 Enabling this option will pass "-Os" instead of "-O2" to gcc
1210 resulting in a smaller kernel.
1211
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001212 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001213
Randy Dunlap08470622006-09-30 23:28:13 -07001214config SYSCTL
1215 bool
1216
Randy Dunlapb943c462009-03-10 12:55:46 -07001217config ANON_INODES
1218 bool
1219
David Rientjes6a108a12011-01-20 14:44:16 -08001220menuconfig EXPERT
1221 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001222 # Unhide debug options, to make the on-by-default options visible
1223 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 help
1225 This option allows certain base kernel options and settings
1226 to be disabled or tweaked. This is for specialized
1227 environments which can tolerate a "non-standard" kernel.
1228 Only use this if you really know what you are doing.
1229
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001230config HAVE_UID16
1231 bool
1232
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001233config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001234 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001235 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001236 default y
1237 help
1238 This enables the legacy 16-bit UID syscall wrappers.
1239
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001240config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001241 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001242 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001243 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001244 select SYSCTL
1245 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001246 sys_sysctl uses binary paths that have been found challenging
1247 to properly maintain and use. The interface in /proc/sys
1248 using paths with ascii names is now the primary path to this
1249 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001250
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001251 Almost nothing using the binary sysctl interface so if you are
1252 trying to save some space it is probably safe to disable this,
1253 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001254
WANG Congc736de62011-11-02 13:39:25 -07001255 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001256
Catalin Marinas7ac57a82012-10-08 16:28:16 -07001257config SYSCTL_EXCEPTION_TRACE
1258 bool
1259 help
1260 Enable support for /proc/sys/debug/exception-trace.
1261
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001263 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 default y
1265 help
1266 Say Y here to let the kernel print out symbolic crash information and
1267 symbolic stack backtraces. This increases the size of the kernel
1268 somewhat, as all symbols have to be loaded into the kernel image.
1269
1270config KALLSYMS_ALL
1271 bool "Include all symbols in kallsyms"
1272 depends on DEBUG_KERNEL && KALLSYMS
1273 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001274 Normally kallsyms only contains the symbols of functions for nicer
1275 OOPS messages and backtraces (i.e., symbols from the text and inittext
1276 sections). This is sufficient for most cases. And only in very rare
1277 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1278 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001280 This option makes sure that all symbols are loaded into the kernel
1281 image (i.e., symbols from all sections) in cost of increased kernel
1282 size (depending on the kernel configuration, it may be 300KiB or
1283 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001285 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001286
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001287config HOTPLUG
Greg Kroah-Hartman45f035a2012-09-04 17:01:08 -07001288 def_bool y
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001289
Matt Mackalld59745c2005-05-01 08:59:02 -07001290config PRINTK
1291 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001292 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001293 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001294 help
1295 This option enables normal printk support. Removing it
1296 eliminates most of the message strings from the kernel image
1297 and makes the kernel more or less silent. As this makes it
1298 very difficult to diagnose system problems, saying N here is
1299 strongly discouraged.
1300
Matt Mackallc8538a72005-05-01 08:59:01 -07001301config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001302 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001303 default y
1304 help
1305 Disabling this option eliminates support for BUG and WARN, reducing
1306 the size of your kernel image and potentially quietly ignoring
1307 numerous fatal conditions. You should only consider disabling this
1308 option for embedded systems with no facilities for reporting errors.
1309 Just say Y.
1310
Matt Mackall708e9a72006-01-08 01:05:25 -08001311config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001312 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001313 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001314 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001315 help
1316 Enable support for generating core dumps. Disabling saves about 4k.
1317
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001318
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001319config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001320 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001321 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001322 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001323 default y
1324 help
1325 This option allows to disable the internal PC-Speaker
1326 support, saving some memory.
1327
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001328config HAVE_PCSPKR_PLATFORM
1329 bool
1330
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331config BASE_FULL
1332 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001333 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 help
1335 Disabling this option reduces the size of miscellaneous core
1336 kernel data structures. This saves memory on small machines,
1337 but may reduce performance.
1338
1339config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001340 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001342 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 help
1344 Disabling this option will cause the kernel to be built without
1345 support for "fast userspace mutexes". The resulting kernel may not
1346 run glibc-based applications correctly.
1347
1348config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001349 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001351 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 help
1353 Disabling this option will cause the kernel to be built without
1354 support for epoll family of system calls.
1355
Davide Libenzifba2afa2007-05-10 22:23:13 -07001356config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001357 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001358 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001359 default y
1360 help
1361 Enable the signalfd() system call that allows to receive signals
1362 on a file descriptor.
1363
1364 If unsure, say Y.
1365
Davide Libenzib215e282007-05-10 22:23:16 -07001366config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001367 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001368 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001369 default y
1370 help
1371 Enable the timerfd() system call that allows to receive timer
1372 events on a file descriptor.
1373
1374 If unsure, say Y.
1375
Davide Libenzie1ad7462007-05-10 22:23:19 -07001376config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001377 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001378 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001379 default y
1380 help
1381 Enable the eventfd() system call that allows to receive both
1382 kernel notification (ie. KAIO) or userspace notifications.
1383
1384 If unsure, say Y.
1385
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001387 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 default y
1389 depends on MMU
1390 help
1391 The shmem is an internal filesystem used to manage shared memory.
1392 It is backed by swap and manages resource limits. It is also exported
1393 to userspace as tmpfs if TMPFS is enabled. Disabling this
1394 option replaces shmem and tmpfs with the much simpler ramfs code,
1395 which may be appropriate on small systems without swap.
1396
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001397config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001398 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001399 default y
1400 help
1401 This option enables POSIX asynchronous I/O which may by used
1402 by some high performance threaded applications. Disabling
1403 this option saves about 7k.
1404
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001405config EMBEDDED
1406 bool "Embedded system"
1407 select EXPERT
1408 help
1409 This option should be enabled if compiling the kernel for
1410 an embedded system so certain expert options are available
1411 for configuration.
1412
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001413config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001414 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001415 help
1416 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001417
Peter Zijlstra906010b2009-09-21 16:08:49 +02001418config PERF_USE_VMALLOC
1419 bool
1420 help
1421 See tools/perf/design.txt for details
1422
Ingo Molnar57c0c152009-09-21 12:20:38 +02001423menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001424
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001425config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001426 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001427 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001428 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001429 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001430 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001431 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001432 Enable kernel support for various performance events provided
1433 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001434
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001435 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001436 use of generic tracepoints.
1437
1438 Most modern CPUs support performance events via performance
1439 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001440 types of hw events: such as instructions executed, cachemisses
1441 suffered, or branches mis-predicted - without slowing down the
1442 kernel or applications. These registers can also trigger interrupts
1443 when a threshold number of events have passed - and can thus be
1444 used to profile the code that runs on that CPU.
1445
Ingo Molnar57c0c152009-09-21 12:20:38 +02001446 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001447 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001448 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001449 provides per task and per CPU counters, and it provides event
1450 capabilities on top of those.
1451
1452 Say Y if unsure.
1453
Peter Zijlstra906010b2009-09-21 16:08:49 +02001454config DEBUG_PERF_USE_VMALLOC
1455 default n
1456 bool "Debug: use vmalloc to back perf mmap() buffers"
1457 depends on PERF_EVENTS && DEBUG_KERNEL
1458 select PERF_USE_VMALLOC
1459 help
1460 Use vmalloc memory to back perf mmap() buffers.
1461
1462 Mostly useful for debugging the vmalloc code on platforms
1463 that don't require it.
1464
1465 Say N if unsure.
1466
Thomas Gleixner0793a612008-12-04 20:12:29 +01001467endmenu
1468
Christoph Lameterf8891e52006-06-30 01:55:45 -07001469config VM_EVENT_COUNTERS
1470 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001471 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001472 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001473 VM event counters are needed for event counts to be shown.
1474 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001475 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001476 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001477
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001478config PCI_QUIRKS
1479 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001480 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001481 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001482 help
1483 This enables workarounds for various PCI chipset
1484 bugs/quirks. Disable this only if your target machine is
1485 unaffected by PCI quirks.
1486
Christoph Lameter41ecc552007-05-09 02:32:44 -07001487config SLUB_DEBUG
1488 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001489 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001490 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001491 help
1492 SLUB has extensive debug support features. Disabling these can
1493 result in significant savings in code size. This also disables
1494 SLUB sysfs support. /sys/slab will not exist and there will be
1495 no support for cache validation etc.
1496
Randy Dunlapb943c462009-03-10 12:55:46 -07001497config COMPAT_BRK
1498 bool "Disable heap randomization"
1499 default y
1500 help
1501 Randomizing heap placement makes heap exploits harder, but it
1502 also breaks ancient binaries (including anything libc5 based).
1503 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001504 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001505 /proc/sys/kernel/randomize_va_space to 2.
1506
1507 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1508
Christoph Lameter81819f02007-05-06 14:49:36 -07001509choice
1510 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001511 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001512 help
1513 This option allows to select a slab allocator.
1514
1515config SLAB
1516 bool "SLAB"
1517 help
1518 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001519 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001520 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001521
1522config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001523 bool "SLUB (Unqueued Allocator)"
1524 help
1525 SLUB is a slab allocator that minimizes cache line usage
1526 instead of managing queues of cached objects (SLAB approach).
1527 Per cpu caching is realized using slabs of objects instead
1528 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001529 and has enhanced diagnostics. SLUB is the default choice for
1530 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001531
1532config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001533 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001534 bool "SLOB (Simple Allocator)"
1535 help
Matt Mackall37291452008-02-04 22:29:38 -08001536 SLOB replaces the stock allocator with a drastically simpler
1537 allocator. SLOB is generally more space efficient but
1538 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001539
1540endchoice
1541
Jie Zhangea637632009-12-14 18:00:02 -08001542config MMAP_ALLOW_UNINITIALIZED
1543 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001544 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001545 default n
1546 help
1547 Normally, and according to the Linux spec, anonymous memory obtained
1548 from mmap() has it's contents cleared before it is passed to
1549 userspace. Enabling this config option allows you to request that
1550 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1551 providing a huge performance boost. If this option is not enabled,
1552 then the flag will be ignored.
1553
1554 This is taken advantage of by uClibc's malloc(), and also by
1555 ELF-FDPIC binfmt's brk and stack allocator.
1556
1557 Because of the obvious security issues, this option should only be
1558 enabled on embedded devices where you control what is run in
1559 userspace. Since that isn't generally a problem on no-MMU systems,
1560 it is normally safe to say Y here.
1561
1562 See Documentation/nommu-mmap.txt for more information.
1563
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001564config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001565 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001566 help
1567 Say Y here to enable the extended profiling support mechanisms used
1568 by profilers such as OProfile.
1569
Ingo Molnar5f87f112008-07-23 14:15:22 +02001570#
1571# Place an empty function call at each tracepoint site. Can be
1572# dynamically changed for a probe function.
1573#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001574config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001575 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001576
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001577source "arch/Kconfig"
1578
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579endmenu # General setup
1580
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001581config HAVE_GENERIC_DMA_COHERENT
1582 bool
1583 default n
1584
Linus Torvalds158a9622008-01-02 13:04:48 -08001585config SLABINFO
1586 bool
1587 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001588 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001589 default y
1590
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001591config RT_MUTEXES
1592 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001593
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594config BASE_SMALL
1595 int
1596 default 0 if BASE_FULL
1597 default 1 if !BASE_FULL
1598
Jan Engelhardt66da5732007-07-15 23:39:29 -07001599menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 bool "Enable loadable module support"
1601 help
1602 Kernel modules are small pieces of compiled code which can
1603 be inserted in the running kernel, rather than being
1604 permanently built into the kernel. You use the "modprobe"
1605 tool to add (and sometimes remove) them. If you say Y here,
1606 many parts of the kernel can be built as modules (by
1607 answering M instead of Y where indicated): this is most
1608 useful for infrequently used options which are not required
1609 for booting. For more information, see the man pages for
1610 modprobe, lsmod, modinfo, insmod and rmmod.
1611
1612 If you say Y here, you will need to run "make
1613 modules_install" to put the modules under /lib/modules/
1614 where modprobe can find them (you may need to be root to do
1615 this).
1616
1617 If unsure, say Y.
1618
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001619if MODULES
1620
Linus Torvalds826e4502008-05-04 17:04:16 -07001621config MODULE_FORCE_LOAD
1622 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001623 default n
1624 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001625 Allow loading of modules without version information (ie. modprobe
1626 --force). Forced module loading sets the 'F' (forced) taint flag and
1627 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001628
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629config MODULE_UNLOAD
1630 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 help
1632 Without this option you will not be able to unload any
1633 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001634 anyway), which makes your kernel smaller, faster
1635 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636
1637config MODULE_FORCE_UNLOAD
1638 bool "Forced module unloading"
1639 depends on MODULE_UNLOAD && EXPERIMENTAL
1640 help
1641 This option allows you to force a module to unload, even if the
1642 kernel believes it is unsafe: the kernel will remove the module
1643 without waiting for anyone to stop using it (using the -f option to
1644 rmmod). This is mainly for kernel developers and desperate users.
1645 If unsure, say N.
1646
Linus Torvalds1da177e2005-04-16 15:20:36 -07001647config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001648 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 help
1650 Usually, you have to use modules compiled with your kernel.
1651 Saying Y here makes it sometimes possible to use modules
1652 compiled for different kernels, by adding enough information
1653 to the modules to (hopefully) spot any changes which would
1654 make them incompatible with the kernel you are running. If
1655 unsure, say N.
1656
1657config MODULE_SRCVERSION_ALL
1658 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 help
1660 Modules which contain a MODULE_VERSION get an extra "srcversion"
1661 field inserted into their modinfo section, which contains a
1662 sum of the source files which made it. This helps maintainers
1663 see exactly which source was used to build a module (since
1664 others sometimes change the module source without updating
1665 the version). With this option, such a "srcversion" field
1666 will be created for all modules. If unsure, say N.
1667
Rusty Russell106a4ee2012-09-26 10:09:40 +01001668config MODULE_SIG
1669 bool "Module signature verification"
1670 depends on MODULES
David Howells48ba2462012-09-26 10:11:03 +01001671 select KEYS
1672 select CRYPTO
1673 select ASYMMETRIC_KEY_TYPE
1674 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1675 select PUBLIC_KEY_ALGO_RSA
1676 select ASN1
1677 select OID_REGISTRY
1678 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001679 help
1680 Check modules for valid signatures upon load: the signature
1681 is simply appended to the module. For more information see
1682 Documentation/module-signing.txt.
1683
David Howellsea0b6dc2012-09-26 10:09:50 +01001684 !!!WARNING!!! If you enable this option, you MUST make sure that the
1685 module DOES NOT get stripped after being signed. This includes the
1686 debuginfo strip done by some packagers (such as rpmbuild) and
1687 inclusion into an initramfs that wants the module size reduced.
1688
Rusty Russell106a4ee2012-09-26 10:09:40 +01001689config MODULE_SIG_FORCE
1690 bool "Require modules to be validly signed"
1691 depends on MODULE_SIG
1692 help
1693 Reject unsigned modules or signed modules for which we don't have a
1694 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001695
1696choice
1697 prompt "Which hash algorithm should modules be signed with?"
1698 depends on MODULE_SIG
1699 help
1700 This determines which sort of hashing algorithm will be used during
1701 signature generation. This algorithm _must_ be built into the kernel
1702 directly so that signature verification can take place. It is not
1703 possible to load a signed module containing the algorithm to check
1704 the signature on that module.
1705
1706config MODULE_SIG_SHA1
1707 bool "Sign modules with SHA-1"
1708 select CRYPTO_SHA1
1709
1710config MODULE_SIG_SHA224
1711 bool "Sign modules with SHA-224"
1712 select CRYPTO_SHA256
1713
1714config MODULE_SIG_SHA256
1715 bool "Sign modules with SHA-256"
1716 select CRYPTO_SHA256
1717
1718config MODULE_SIG_SHA384
1719 bool "Sign modules with SHA-384"
1720 select CRYPTO_SHA512
1721
1722config MODULE_SIG_SHA512
1723 bool "Sign modules with SHA-512"
1724 select CRYPTO_SHA512
1725
1726endchoice
1727
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001728endif # MODULES
1729
Rusty Russell98a79d62008-12-13 21:19:41 +10301730config INIT_ALL_POSSIBLE
1731 bool
1732 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301733 Back when each arch used to define their own cpu_online_mask and
1734 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301735 with all 1s, and others with all 0s. When they were centralised,
1736 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001737 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301738
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739config STOP_MACHINE
1740 bool
1741 default y
1742 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1743 help
1744 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001745
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001746source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001747
1748config PREEMPT_NOTIFIERS
1749 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001750
Steffen Klassert16295be2010-01-06 19:47:10 +11001751config PADATA
1752 depends on SMP
1753 bool
1754
Andi Kleen754b7b62012-10-04 17:11:27 -07001755# Can be selected by architectures with broken toolchains
1756# that get confused by correct const<->read_only section
1757# mappings
1758config BROKEN_RODATA
1759 bool
1760
David Howells4520c6a2012-09-21 23:31:13 +01001761config ASN1
1762 tristate
1763 help
1764 Build a simple ASN.1 grammar compiler that produces a bytecode output
1765 that can be interpreted by the ASN.1 stream decoder and used to
1766 inform it as to what tags are to be expected in a stream and what
1767 functions to call on what tags.
1768
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001769source "kernel/Kconfig.locks"