blob: ed6334dd5e718cb874e4b4d272b652fadb101a8d [file] [log] [blame]
Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
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56 drivers that have been replaced by something else, and/or are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
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530270config FHANDLE
271 bool "open by fhandle syscalls"
272 select EXPORTFS
273 help
274 If you say Y here, a user level program will be able to map
275 file names to handle and then later use the handle for
276 different file system operations. This is useful in implementing
277 userspace file servers, which now track files using handles instead
278 of names. The handle would remain the same even if file names
279 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
280 syscalls.
281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282config AUDIT
283 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100284 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 help
286 Enable auditing infrastructure that can be used with another
287 kernel subsystem, such as SELinux (which requires this for
288 logging of avc messages output). Does not do system-call
289 auditing without CONFIG_AUDITSYSCALL.
290
291config AUDITSYSCALL
292 bool "Enable system-call auditing support"
Will Deacon8f827a12012-07-06 15:48:16 +0100293 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 default y if SECURITY_SELINUX
295 help
296 Enable low-overhead system-call auditing infrastructure that
297 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500298 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
Eric Paris939a67f2009-12-17 20:12:06 -0500300config AUDIT_WATCH
301 def_bool y
302 depends on AUDITSYSCALL
303 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Al Viro74c3cbe2007-07-22 08:04:18 -0400305config AUDIT_TREE
306 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400307 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500308 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400309
Eric Paris633b4542012-01-03 14:23:08 -0500310config AUDIT_LOGINUID_IMMUTABLE
311 bool "Make audit loginuid immutable"
312 depends on AUDIT
313 help
Linus Torvaldsf429ee32012-01-17 16:06:51 -0800314 The config option toggles if a task setting its loginuid requires
Eric Paris633b4542012-01-03 14:23:08 -0500315 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
316 but should instead only allow setting its loginuid if it was never
317 previously set. On systems which use systemd or a similar central
318 process to restart login services this should be set to true. On older
319 systems in which an admin would typically have to directly stop and
320 start processes this should be set to false. Setting this to true allows
321 one to drop potentially dangerous capabilites from the login tasks,
322 but may not be backwards compatible with older init systems.
323
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000324source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200325source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000326
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200327menu "CPU/Task time and stats accounting"
328
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200329choice
330 prompt "Cputime accounting"
331 default TICK_CPU_ACCOUNTING if !PPC64
332 default VIRT_CPU_ACCOUNTING if PPC64
333
334# Kind of a stub config for the pure tick based cputime accounting
335config TICK_CPU_ACCOUNTING
336 bool "Simple tick based cputime accounting"
337 depends on !S390
338 help
339 This is the basic tick based cputime accounting that maintains
340 statistics about user, system and idle time spent on per jiffies
341 granularity.
342
343 If unsure, say Y.
344
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200345config VIRT_CPU_ACCOUNTING
346 bool "Deterministic task and CPU time accounting"
347 depends on HAVE_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 Weisbeckerfdf9c352012-09-09 14:56:31 +0200357config IRQ_TIME_ACCOUNTING
358 bool "Fine granularity task level IRQ time accounting"
359 depends on HAVE_IRQ_TIME_ACCOUNTING
360 help
361 Select this option to enable fine granularity task irq time
362 accounting. This is done by reading a timestamp on each
363 transitions between softirq and hardirq state, so there can be a
364 small performance impact.
365
366 If in doubt, say N here.
367
368endchoice
369
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200370config BSD_PROCESS_ACCT
371 bool "BSD Process Accounting"
372 help
373 If you say Y here, a user level program will be able to instruct the
374 kernel (via a special system call) to write process accounting
375 information to a file: whenever a process exits, information about
376 that process will be appended to the file by the kernel. The
377 information includes things such as creation time, owning user,
378 command name, memory usage, controlling terminal etc. (the complete
379 list is in the struct acct in <file:include/linux/acct.h>). It is
380 up to the user level program to do useful things with this
381 information. This is generally a good idea, so say Y.
382
383config BSD_PROCESS_ACCT_V3
384 bool "BSD Process Accounting version 3 file format"
385 depends on BSD_PROCESS_ACCT
386 default n
387 help
388 If you say Y here, the process accounting information is written
389 in a new file format that also logs the process IDs of each
390 process and it's parent. Note that this file format is incompatible
391 with previous v0/v1/v2 file formats, so you will need updated tools
392 for processing it. A preliminary version of these tools is available
393 at <http://www.gnu.org/software/acct/>.
394
395config TASKSTATS
396 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
397 depends on NET
398 default n
399 help
400 Export selected statistics for tasks/processes through the
401 generic netlink interface. Unlike BSD process accounting, the
402 statistics are available during the lifetime of tasks/processes as
403 responses to commands. Like BSD accounting, they are sent to user
404 space on task exit.
405
406 Say N if unsure.
407
408config TASK_DELAY_ACCT
409 bool "Enable per-task delay accounting (EXPERIMENTAL)"
410 depends on TASKSTATS
411 help
412 Collect information on time spent by a task waiting for system
413 resources like cpu, synchronous block I/O completion and swapping
414 in pages. Such statistics can help in setting a task's priorities
415 relative to other tasks for cpu, io, rss limits etc.
416
417 Say N if unsure.
418
419config TASK_XACCT
420 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
421 depends on TASKSTATS
422 help
423 Collect extended task accounting data and send the data
424 to userland for processing over the taskstats interface.
425
426 Say N if unsure.
427
428config TASK_IO_ACCOUNTING
429 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
430 depends on TASK_XACCT
431 help
432 Collect information on the number of bytes of storage I/O which this
433 task has caused.
434
435 Say N if unsure.
436
437endmenu # "CPU/Task time and stats accounting"
438
Mike Travisc903ff82009-01-15 12:28:29 -0800439menu "RCU Subsystem"
440
441choice
442 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700443 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800444
Mike Travisc903ff82009-01-15 12:28:29 -0800445config TREE_RCU
446 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700447 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800448 help
449 This option selects the RCU implementation that is
450 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700451 thousands of CPUs. It also scales down nicely to
452 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800453
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700454config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700455 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700456 depends on PREEMPT && SMP
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700457 help
458 This option selects the RCU implementation that is
459 designed for very large SMP systems with hundreds or
460 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700461 is also required. It also scales down nicely to
462 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700463
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700464config TINY_RCU
465 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700466 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700467 help
468 This option selects the RCU implementation that is
469 designed for UP systems from which real-time response
470 is not required. This option greatly reduces the
471 memory footprint of RCU.
472
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700473config TINY_PREEMPT_RCU
474 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700475 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700476 help
477 This option selects the RCU implementation that is designed
478 for real-time UP systems. This option greatly reduces the
479 memory footprint of RCU.
480
Mike Travisc903ff82009-01-15 12:28:29 -0800481endchoice
482
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700483config PREEMPT_RCU
484 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
485 help
486 This option enables preemptible-RCU code that is common between
487 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
488
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200489config RCU_USER_QS
490 bool "Consider userspace as in RCU extended quiescent state"
491 depends on HAVE_RCU_USER_QS && SMP
492 help
493 This option sets hooks on kernel / userspace boundaries and
494 puts RCU in extended quiescent state when the CPU runs in
495 userspace. It means that when a CPU runs in userspace, it is
496 excluded from the global RCU state machine and thus doesn't
497 to keep the timer tick on for RCU.
498
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200499config RCU_USER_QS_FORCE
500 bool "Force userspace extended QS by default"
501 depends on RCU_USER_QS
502 help
503 Set the hooks in user/kernel boundaries by default in order to
504 test this feature that treats userspace as an extended quiescent
505 state until we have a real user like a full adaptive nohz option.
506
Mike Travisc903ff82009-01-15 12:28:29 -0800507config RCU_FANOUT
508 int "Tree-based hierarchical RCU fanout value"
509 range 2 64 if 64BIT
510 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700511 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800512 default 64 if 64BIT
513 default 32 if !64BIT
514 help
515 This option controls the fanout of hierarchical implementations
516 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700517 large numbers of CPUs. This value must be at least the fourth
518 root of NR_CPUS, which allows NR_CPUS to be insanely large.
519 The default value of RCU_FANOUT should be used for production
520 systems, but if you are stress-testing the RCU implementation
521 itself, small RCU_FANOUT values allow you to test large-system
522 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800523
524 Select a specific number if testing RCU itself.
525 Take the default if unsure.
526
Paul E. McKenney8932a632012-04-19 12:20:14 -0700527config RCU_FANOUT_LEAF
528 int "Tree-based hierarchical RCU leaf-level fanout value"
529 range 2 RCU_FANOUT if 64BIT
530 range 2 RCU_FANOUT if !64BIT
531 depends on TREE_RCU || TREE_PREEMPT_RCU
532 default 16
533 help
534 This option controls the leaf-level fanout of hierarchical
535 implementations of RCU, and allows trading off cache misses
536 against lock contention. Systems that synchronize their
537 scheduling-clock interrupts for energy-efficiency reasons will
538 want the default because the smaller leaf-level fanout keeps
539 lock contention levels acceptably low. Very large systems
540 (hundreds or thousands of CPUs) will instead want to set this
541 value to the maximum value possible in order to reduce the
542 number of cache misses incurred during RCU's grace-period
543 initialization. These systems tend to run CPU-bound, and thus
544 are not helped by synchronized interrupts, and thus tend to
545 skew them, which reduces lock contention enough that large
546 leaf-level fanouts work well.
547
548 Select a specific number if testing RCU itself.
549
550 Select the maximum permissible value for large systems.
551
552 Take the default if unsure.
553
Mike Travisc903ff82009-01-15 12:28:29 -0800554config RCU_FANOUT_EXACT
555 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700556 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800557 default n
558 help
559 This option forces use of the exact RCU_FANOUT value specified,
560 regardless of imbalances in the hierarchy. This is useful for
561 testing RCU itself, and might one day be useful on systems with
562 strong NUMA behavior.
563
564 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
565
566 Say N if unsure.
567
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800568config RCU_FAST_NO_HZ
569 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700570 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800571 default n
572 help
573 This option causes RCU to attempt to accelerate grace periods
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700574 in order to allow CPUs to enter dynticks-idle state more
575 quickly. On the other hand, this option increases the overhead
576 of the dynticks-idle checking, particularly on systems with
577 large numbers of CPUs.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800578
579 Say Y if energy efficiency is critically important, particularly
580 if you have relatively few CPUs.
581
582 Say N if you are unsure.
583
Mike Travisc903ff82009-01-15 12:28:29 -0800584config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700585 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800586 select DEBUG_FS
587 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700588 This option provides tracing for the TREE_RCU and
589 TREE_PREEMPT_RCU implementations, permitting Makefile to
590 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800591
Paul E. McKenney24278d12010-09-27 17:25:23 -0700592config RCU_BOOST
593 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800594 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700595 default n
596 help
597 This option boosts the priority of preempted RCU readers that
598 block the current preemptible RCU grace period for too long.
599 This option also prevents heavy loads from blocking RCU
600 callback invocation for all flavors of RCU.
601
602 Say Y here if you are working with real-time apps or heavy loads
603 Say N here if you are unsure.
604
605config RCU_BOOST_PRIO
606 int "Real-time priority to boost RCU readers to"
607 range 1 99
608 depends on RCU_BOOST
609 default 1
610 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700611 This option specifies the real-time priority to which long-term
612 preempted RCU readers are to be boosted. If you are working
613 with a real-time application that has one or more CPU-bound
614 threads running at a real-time priority level, you should set
615 RCU_BOOST_PRIO to a priority higher then the highest-priority
616 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
617 of 1 is appropriate in the common case, which is real-time
618 applications that do not have any CPU-bound threads.
619
620 Some real-time applications might not have a single real-time
621 thread that saturates a given CPU, but instead might have
622 multiple real-time threads that, taken together, fully utilize
623 that CPU. In this case, you should set RCU_BOOST_PRIO to
624 a priority higher than the lowest-priority thread that is
625 conspiring to prevent the CPU from running any non-real-time
626 tasks. For example, if one thread at priority 10 and another
627 thread at priority 5 are between themselves fully consuming
628 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
629 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700630
631 Specify the real-time priority, or take the default if unsure.
632
633config RCU_BOOST_DELAY
634 int "Milliseconds to delay boosting after RCU grace-period start"
635 range 0 3000
636 depends on RCU_BOOST
637 default 500
638 help
639 This option specifies the time to wait after the beginning of
640 a given grace period before priority-boosting preempted RCU
641 readers blocking that grace period. Note that any RCU reader
642 blocking an expedited RCU grace period is boosted immediately.
643
644 Accept the default if unsure.
645
Mike Travisc903ff82009-01-15 12:28:29 -0800646endmenu # "RCU Subsystem"
647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700649 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 ---help---
651 This option enables the complete Linux kernel ".config" file
652 contents to be saved in the kernel. It provides documentation
653 of which kernel options are used in a running kernel or in an
654 on-disk kernel. This information can be extracted from the kernel
655 image file with the script scripts/extract-ikconfig and used as
656 input to rebuild the current kernel or to build another kernel.
657 It can also be extracted from a running kernel by reading
658 /proc/config.gz if enabled (below).
659
660config IKCONFIG_PROC
661 bool "Enable access to .config through /proc/config.gz"
662 depends on IKCONFIG && PROC_FS
663 ---help---
664 This option enables access to the kernel configuration file
665 through /proc/config.gz.
666
Alistair John Strachan794543a2007-05-08 00:31:15 -0700667config LOG_BUF_SHIFT
668 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
669 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700670 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700671 help
672 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700673 Examples:
674 17 => 128 KB
675 16 => 64 KB
676 15 => 32 KB
677 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700678 13 => 8 KB
679 12 => 4 KB
680
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800681#
682# Architectures with an unreliable sched_clock() should select this:
683#
684config HAVE_UNSTABLE_SCHED_CLOCK
685 bool
686
Li Zefan23964d22009-01-15 13:50:58 -0800687menuconfig CGROUPS
688 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800689 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700690 help
Li Zefan23964d22009-01-15 13:50:58 -0800691 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800692 use with process control subsystems such as Cpusets, CFS, memory
693 controls or device isolation.
694 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800695 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800696 - Documentation/cgroups/ (features for grouping, isolation
697 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700698
699 Say N if unsure.
700
Li Zefan23964d22009-01-15 13:50:58 -0800701if CGROUPS
702
Paul Menage006cb992007-10-18 23:39:43 -0700703config CGROUP_DEBUG
704 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700705 default n
Paul Menage006cb992007-10-18 23:39:43 -0700706 help
707 This option enables a simple cgroup subsystem that
708 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800709 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700710
Li Zefan23964d22009-01-15 13:50:58 -0800711 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700712
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700713config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800714 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800715 help
716 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700717 cgroup.
718
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700719config CGROUP_DEVICE
720 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700721 help
722 Provides a cgroup implementing whitelists for devices which
723 a process in the cgroup can mknod or open.
724
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725config CPUSETS
726 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700728 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 allow dynamically partitioning a system into sets of CPUs and
730 Memory Nodes and assigning tasks to run only within those sets.
731 This is primarily useful on large SMP or NUMA systems.
732
733 Say N if unsure.
734
Li Zefan23964d22009-01-15 13:50:58 -0800735config PROC_PID_CPUSET
736 bool "Include legacy /proc/<pid>/cpuset file"
737 depends on CPUSETS
738 default y
739
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100740config CGROUP_CPUACCT
741 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100742 help
743 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800744 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100745
Pavel Emelianove552b662008-02-07 00:13:49 -0800746config RESOURCE_COUNTERS
747 bool "Resource counters"
748 help
749 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800750 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800751
Andrew Mortonc255a452012-07-31 16:43:02 -0700752config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800753 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700754 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700755 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800756 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700757 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100758 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800759
760 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700761 associated with each page of memory in the system. By this,
762 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
763 usage tracking struct at boot. Total amount of this is printed out
764 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800765
766 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700767 sure you need the memory resource controller. Even when you enable
768 this, you can set "cgroup_disable=memory" at your boot option to
769 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800770 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800771
Balbir Singhcf475ad2008-04-29 01:00:16 -0700772 This config option also selects MM_OWNER config option, which
773 could in turn add some fork/exit overhead.
774
Andrew Mortonc255a452012-07-31 16:43:02 -0700775config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700776 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700777 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800778 help
779 Add swap management feature to memory resource controller. When you
780 enable this, you can limit mem+swap usage per cgroup. In other words,
781 when you disable this, memory resource controller has no cares to
782 usage of swap...a process can exhaust all of the swap. This extension
783 is useful when you want to avoid exhaustion swap but this itself
784 adds more overheads and consumes memory for remembering information.
785 Especially if you use 32bit system or small memory system, please
786 be careful about enabling this. When memory resource controller
787 is disabled by boot option, this will be automatically disabled and
788 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700789 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700790 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
791 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -0700792config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -0800793 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700794 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800795 default y
796 help
797 Memory Resource Controller Swap Extension comes with its price in
798 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700799 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800800 and let the user enable it by swapaccount boot command line
801 parameter should have this option unselected.
802 For those who want to have the feature enabled by default should
803 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700804 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700805config MEMCG_KMEM
Glauber Costae5671df2011-12-11 21:47:01 +0000806 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
Andrew Mortonc255a452012-07-31 16:43:02 -0700807 depends on MEMCG && EXPERIMENTAL
Glauber Costae5671df2011-12-11 21:47:01 +0000808 default n
809 help
810 The Kernel Memory extension for Memory Resource Controller can limit
811 the amount of memory used by kernel objects in the system. Those are
812 fundamentally different from the entities handled by the standard
813 Memory Controller, which are page-based, and can be swapped. Users of
814 the kmem extension can use it to guarantee that no group of processes
815 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800816
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700817config CGROUP_HUGETLB
818 bool "HugeTLB Resource Controller for Control Groups"
819 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
820 default n
821 help
822 Provides a cgroup Resource Controller for HugeTLB pages.
823 When you enable this, you can put a per cgroup limit on HugeTLB usage.
824 The limit is enforced during page fault. Since HugeTLB doesn't
825 support page reclaim, enforcing the limit at page fault time implies
826 that, the application will get SIGBUS signal if it tries to access
827 HugeTLB pages beyond its limit. This requires the application to know
828 beforehand how much HugeTLB pages it would require for its use. The
829 control group is tracked in the third page lru pointer. This means
830 that we cannot use the controller with huge page less than 3 pages.
831
Stephane Eraniane5d13672011-02-14 11:20:01 +0200832config CGROUP_PERF
833 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
834 depends on PERF_EVENTS && CGROUPS
835 help
836 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800837 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200838 designated cpu.
839
840 Say N if unsure.
841
Dhaval Giani7c941432010-01-20 13:26:18 +0100842menuconfig CGROUP_SCHED
843 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100844 default n
845 help
846 This feature lets CPU scheduler recognize task groups and control CPU
847 bandwidth allocation to such task groups. It uses cgroups to group
848 tasks.
849
850if CGROUP_SCHED
851config FAIR_GROUP_SCHED
852 bool "Group scheduling for SCHED_OTHER"
853 depends on CGROUP_SCHED
854 default CGROUP_SCHED
855
Paul Turnerab84d312011-07-21 09:43:28 -0700856config CFS_BANDWIDTH
857 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
858 depends on EXPERIMENTAL
859 depends on FAIR_GROUP_SCHED
860 default n
861 help
862 This option allows users to define CPU bandwidth rates (limits) for
863 tasks running within the fair group scheduler. Groups with no limit
864 set are considered to be unconstrained and will run with no
865 restriction.
866 See tip/Documentation/scheduler/sched-bwc.txt for more information.
867
Dhaval Giani7c941432010-01-20 13:26:18 +0100868config RT_GROUP_SCHED
869 bool "Group scheduling for SCHED_RR/FIFO"
870 depends on EXPERIMENTAL
871 depends on CGROUP_SCHED
872 default n
873 help
874 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800875 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100876 schedule realtime tasks for non-root users until you allocate
877 realtime bandwidth for them.
878 See Documentation/scheduler/sched-rt-group.txt for more information.
879
880endif #CGROUP_SCHED
881
Vivek Goyalafc24d42010-04-26 19:27:56 +0200882config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -0800883 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700884 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200885 default n
886 ---help---
887 Generic block IO controller cgroup interface. This is the common
888 cgroup interface which should be used by various IO controlling
889 policies.
890
891 Currently, CFQ IO scheduler uses it to recognize task groups and
892 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400893 to such task groups. It is also used by bio throttling logic in
894 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200895
896 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400897 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000898 enabling proportional weight division of disk bandwidth in CFQ, set
899 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000900 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200901
902 See Documentation/cgroups/blkio-controller.txt for more information.
903
904config DEBUG_BLK_CGROUP
905 bool "Enable Block IO controller debugging"
906 depends on BLK_CGROUP
907 default n
908 ---help---
909 Enable some debugging help. Currently it exports additional stat
910 files in a cgroup which can be useful for debugging.
911
Li Zefan23964d22009-01-15 13:50:58 -0800912endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800913
Cyrill Gorcunov067bce12012-01-12 17:20:49 -0800914config CHECKPOINT_RESTORE
915 bool "Checkpoint/restore support" if EXPERT
916 default n
917 help
918 Enables additional kernel features in a sake of checkpoint/restore.
919 In particular it adds auxiliary prctl codes to setup process text,
920 data and heap segment sizes, and a few additional /proc filesystem
921 entries.
922
923 If unsure, say N here.
924
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700925menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800926 bool "Namespaces support" if EXPERT
927 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800928 help
929 Provides the way to make tasks work with different objects using
930 the same id. For example same IPC id may refer to different objects
931 or same user id or pid may refer to different tasks when used in
932 different namespaces.
933
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700934if NAMESPACES
935
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800936config UTS_NS
937 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700938 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800939 help
940 In this namespace tasks see different info provided with the
941 uname() system call
942
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800943config IPC_NS
944 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700945 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700946 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800947 help
948 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700949 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800950
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800951config USER_NS
952 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700953 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700954 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -0800955 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700956
Eric W. Biederman5673a942011-11-17 10:23:55 -0800957 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800958 help
959 This allows containers, i.e. vservers, to use user namespaces
960 to provide different user info for different servers.
961 If unsure, say N.
962
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800963config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700964 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700965 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800966 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300967 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100968 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800969 pid namespaces. This is a building block of containers.
970
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800971config NET_NS
972 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700973 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700974 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800975 help
976 Allow user space to create what appear to be multiple instances
977 of the network stack.
978
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700979endif # NAMESPACES
980
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700981config UIDGID_CONVERTED
982 # True if all of the selected software conmponents are known
983 # to have uid_t and gid_t converted to kuid_t and kgid_t
984 # where appropriate and are otherwise safe to use with
985 # the user namespace.
986 bool
987 default y
988
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700989 # Networking
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700990 depends on NET_9P = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700991
992 # Filesystems
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700993 depends on 9P_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700994 depends on AFS_FS = n
995 depends on AUTOFS4_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700996 depends on CEPH_FS = n
997 depends on CIFS = n
998 depends on CODA_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700999 depends on FUSE_FS = n
1000 depends on GFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001001 depends on NCP_FS = n
1002 depends on NFSD = n
1003 depends on NFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001004 depends on OCFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001005 depends on XFS_FS = n
1006
Eric W. Biederman5673a942011-11-17 10:23:55 -08001007config UIDGID_STRICT_TYPE_CHECKS
1008 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001009 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001010 default n
1011 help
1012 While the nececessary conversions are being added to all subsystems this option allows
1013 the code to continue to build for unconverted subsystems.
1014
1015 Say Y here if you want the strict type checking enabled
1016
Mike Galbraith5091faa2010-11-30 14:18:03 +01001017config SCHED_AUTOGROUP
1018 bool "Automatic process group scheduling"
1019 select EVENTFD
1020 select CGROUPS
1021 select CGROUP_SCHED
1022 select FAIR_GROUP_SCHED
1023 help
1024 This option optimizes the scheduler for common desktop workloads by
1025 automatically creating and populating task groups. This separation
1026 of workloads isolates aggressive CPU burners (like build jobs) from
1027 desktop applications. Task group autogeneration is currently based
1028 upon task session.
1029
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001030config MM_OWNER
1031 bool
1032
1033config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001034 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001035 depends on SYSFS
1036 default n
1037 help
1038 This option adds code that switches the layout of the "block" class
1039 devices, to not show up in /sys/class/block/, but only in
1040 /sys/block/.
1041
1042 This switch is only active when the sysfs.deprecated=1 boot option is
1043 passed or the SYSFS_DEPRECATED_V2 option is set.
1044
1045 This option allows new kernels to run on old distributions and tools,
1046 which might get confused by /sys/class/block/. Since 2007/2008 all
1047 major distributions and tools handle this just fine.
1048
1049 Recent distributions and userspace tools after 2009/2010 depend on
1050 the existence of /sys/class/block/, and will not work with this
1051 option enabled.
1052
1053 Only if you are using a new kernel on an old distribution, you might
1054 need to say Y here.
1055
1056config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001057 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001058 default n
1059 depends on SYSFS
1060 depends on SYSFS_DEPRECATED
1061 help
1062 Enable deprecated sysfs by default.
1063
1064 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1065 option.
1066
1067 Only if you are using a new kernel on an old distribution, you might
1068 need to say Y here. Even then, odds are you would not need it
1069 enabled, you can always pass the boot option if absolutely necessary.
1070
1071config RELAY
1072 bool "Kernel->user space relay support (formerly relayfs)"
1073 help
1074 This option enables support for relay interface support in
1075 certain file systems (such as debugfs).
1076 It is designed to provide an efficient mechanism for tools and
1077 facilities to relay large amounts of data from kernel space to
1078 user space.
1079
1080 If unsure, say N.
1081
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001082config BLK_DEV_INITRD
1083 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1084 depends on BROKEN || !FRV
1085 help
1086 The initial RAM filesystem is a ramfs which is loaded by the
1087 boot loader (loadlin or lilo) and that is mounted as root
1088 before the normal boot procedure. It is typically used to
1089 load modules needed to mount the "real" root file system,
1090 etc. See <file:Documentation/initrd.txt> for details.
1091
1092 If RAM disk support (BLK_DEV_RAM) is also included, this
1093 also enables initial RAM disk (initrd) support and adds
1094 15 Kbytes (more on some other architectures) to the kernel size.
1095
1096 If unsure say Y.
1097
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001098if BLK_DEV_INITRD
1099
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001100source "usr/Kconfig"
1101
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001102endif
1103
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001104config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001105 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001106 help
1107 Enabling this option will pass "-Os" instead of "-O2" to gcc
1108 resulting in a smaller kernel.
1109
jkacur775a7222008-07-16 00:31:16 +02001110 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001111
Randy Dunlap08470622006-09-30 23:28:13 -07001112config SYSCTL
1113 bool
1114
Randy Dunlapb943c462009-03-10 12:55:46 -07001115config ANON_INODES
1116 bool
1117
David Rientjes6a108a12011-01-20 14:44:16 -08001118menuconfig EXPERT
1119 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001120 # Unhide debug options, to make the on-by-default options visible
1121 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 help
1123 This option allows certain base kernel options and settings
1124 to be disabled or tweaked. This is for specialized
1125 environments which can tolerate a "non-standard" kernel.
1126 Only use this if you really know what you are doing.
1127
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001128config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001129 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinas8c2c3df2012-04-20 14:45:54 +01001130 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) \
1131 || AARCH32_EMULATION
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001132 default y
1133 help
1134 This enables the legacy 16-bit UID syscall wrappers.
1135
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001136config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001137 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001138 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001139 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001140 select SYSCTL
1141 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001142 sys_sysctl uses binary paths that have been found challenging
1143 to properly maintain and use. The interface in /proc/sys
1144 using paths with ascii names is now the primary path to this
1145 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001146
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001147 Almost nothing using the binary sysctl interface so if you are
1148 trying to save some space it is probably safe to disable this,
1149 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001150
WANG Congc736de62011-11-02 13:39:25 -07001151 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001152
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001154 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 default y
1156 help
1157 Say Y here to let the kernel print out symbolic crash information and
1158 symbolic stack backtraces. This increases the size of the kernel
1159 somewhat, as all symbols have to be loaded into the kernel image.
1160
1161config KALLSYMS_ALL
1162 bool "Include all symbols in kallsyms"
1163 depends on DEBUG_KERNEL && KALLSYMS
1164 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001165 Normally kallsyms only contains the symbols of functions for nicer
1166 OOPS messages and backtraces (i.e., symbols from the text and inittext
1167 sections). This is sufficient for most cases. And only in very rare
1168 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1169 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001171 This option makes sure that all symbols are loaded into the kernel
1172 image (i.e., symbols from all sections) in cost of increased kernel
1173 size (depending on the kernel configuration, it may be 300KiB or
1174 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001176 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001177
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001178config HOTPLUG
Greg Kroah-Hartman45f035a2012-09-04 17:01:08 -07001179 def_bool y
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001180
Matt Mackalld59745c2005-05-01 08:59:02 -07001181config PRINTK
1182 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001183 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001184 help
1185 This option enables normal printk support. Removing it
1186 eliminates most of the message strings from the kernel image
1187 and makes the kernel more or less silent. As this makes it
1188 very difficult to diagnose system problems, saying N here is
1189 strongly discouraged.
1190
Matt Mackallc8538a72005-05-01 08:59:01 -07001191config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001192 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001193 default y
1194 help
1195 Disabling this option eliminates support for BUG and WARN, reducing
1196 the size of your kernel image and potentially quietly ignoring
1197 numerous fatal conditions. You should only consider disabling this
1198 option for embedded systems with no facilities for reporting errors.
1199 Just say Y.
1200
Matt Mackall708e9a72006-01-08 01:05:25 -08001201config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001202 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001203 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001204 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001205 help
1206 Enable support for generating core dumps. Disabling saves about 4k.
1207
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001208
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001209config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001210 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001211 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001212 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001213 default y
1214 help
1215 This option allows to disable the internal PC-Speaker
1216 support, saving some memory.
1217
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001218config HAVE_PCSPKR_PLATFORM
1219 bool
1220
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221config BASE_FULL
1222 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001223 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 help
1225 Disabling this option reduces the size of miscellaneous core
1226 kernel data structures. This saves memory on small machines,
1227 but may reduce performance.
1228
1229config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001230 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001232 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 help
1234 Disabling this option will cause the kernel to be built without
1235 support for "fast userspace mutexes". The resulting kernel may not
1236 run glibc-based applications correctly.
1237
1238config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001239 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001241 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 help
1243 Disabling this option will cause the kernel to be built without
1244 support for epoll family of system calls.
1245
Davide Libenzifba2afa2007-05-10 22:23:13 -07001246config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001247 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001248 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001249 default y
1250 help
1251 Enable the signalfd() system call that allows to receive signals
1252 on a file descriptor.
1253
1254 If unsure, say Y.
1255
Davide Libenzib215e282007-05-10 22:23:16 -07001256config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001257 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001258 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001259 default y
1260 help
1261 Enable the timerfd() system call that allows to receive timer
1262 events on a file descriptor.
1263
1264 If unsure, say Y.
1265
Davide Libenzie1ad7462007-05-10 22:23:19 -07001266config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001267 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001268 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001269 default y
1270 help
1271 Enable the eventfd() system call that allows to receive both
1272 kernel notification (ie. KAIO) or userspace notifications.
1273
1274 If unsure, say Y.
1275
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001277 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 default y
1279 depends on MMU
1280 help
1281 The shmem is an internal filesystem used to manage shared memory.
1282 It is backed by swap and manages resource limits. It is also exported
1283 to userspace as tmpfs if TMPFS is enabled. Disabling this
1284 option replaces shmem and tmpfs with the much simpler ramfs code,
1285 which may be appropriate on small systems without swap.
1286
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001287config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001288 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001289 default y
1290 help
1291 This option enables POSIX asynchronous I/O which may by used
1292 by some high performance threaded applications. Disabling
1293 this option saves about 7k.
1294
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001295config EMBEDDED
1296 bool "Embedded system"
1297 select EXPERT
1298 help
1299 This option should be enabled if compiling the kernel for
1300 an embedded system so certain expert options are available
1301 for configuration.
1302
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001303config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001304 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001305 help
1306 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001307
Peter Zijlstra906010b2009-09-21 16:08:49 +02001308config PERF_USE_VMALLOC
1309 bool
1310 help
1311 See tools/perf/design.txt for details
1312
Ingo Molnar57c0c152009-09-21 12:20:38 +02001313menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001314
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001315config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001316 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001317 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001318 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001319 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001320 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001321 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001322 Enable kernel support for various performance events provided
1323 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001324
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001325 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001326 use of generic tracepoints.
1327
1328 Most modern CPUs support performance events via performance
1329 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001330 types of hw events: such as instructions executed, cachemisses
1331 suffered, or branches mis-predicted - without slowing down the
1332 kernel or applications. These registers can also trigger interrupts
1333 when a threshold number of events have passed - and can thus be
1334 used to profile the code that runs on that CPU.
1335
Ingo Molnar57c0c152009-09-21 12:20:38 +02001336 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001337 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001338 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001339 provides per task and per CPU counters, and it provides event
1340 capabilities on top of those.
1341
1342 Say Y if unsure.
1343
Peter Zijlstra906010b2009-09-21 16:08:49 +02001344config DEBUG_PERF_USE_VMALLOC
1345 default n
1346 bool "Debug: use vmalloc to back perf mmap() buffers"
1347 depends on PERF_EVENTS && DEBUG_KERNEL
1348 select PERF_USE_VMALLOC
1349 help
1350 Use vmalloc memory to back perf mmap() buffers.
1351
1352 Mostly useful for debugging the vmalloc code on platforms
1353 that don't require it.
1354
1355 Say N if unsure.
1356
Thomas Gleixner0793a612008-12-04 20:12:29 +01001357endmenu
1358
Christoph Lameterf8891e52006-06-30 01:55:45 -07001359config VM_EVENT_COUNTERS
1360 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001361 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001362 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001363 VM event counters are needed for event counts to be shown.
1364 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001365 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001366 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001367
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001368config PCI_QUIRKS
1369 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001370 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001371 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001372 help
1373 This enables workarounds for various PCI chipset
1374 bugs/quirks. Disable this only if your target machine is
1375 unaffected by PCI quirks.
1376
Christoph Lameter41ecc552007-05-09 02:32:44 -07001377config SLUB_DEBUG
1378 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001379 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001380 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001381 help
1382 SLUB has extensive debug support features. Disabling these can
1383 result in significant savings in code size. This also disables
1384 SLUB sysfs support. /sys/slab will not exist and there will be
1385 no support for cache validation etc.
1386
Randy Dunlapb943c462009-03-10 12:55:46 -07001387config COMPAT_BRK
1388 bool "Disable heap randomization"
1389 default y
1390 help
1391 Randomizing heap placement makes heap exploits harder, but it
1392 also breaks ancient binaries (including anything libc5 based).
1393 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001394 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001395 /proc/sys/kernel/randomize_va_space to 2.
1396
1397 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1398
Christoph Lameter81819f02007-05-06 14:49:36 -07001399choice
1400 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001401 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001402 help
1403 This option allows to select a slab allocator.
1404
1405config SLAB
1406 bool "SLAB"
1407 help
1408 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001409 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001410 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001411
1412config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001413 bool "SLUB (Unqueued Allocator)"
1414 help
1415 SLUB is a slab allocator that minimizes cache line usage
1416 instead of managing queues of cached objects (SLAB approach).
1417 Per cpu caching is realized using slabs of objects instead
1418 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001419 and has enhanced diagnostics. SLUB is the default choice for
1420 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001421
1422config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001423 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001424 bool "SLOB (Simple Allocator)"
1425 help
Matt Mackall37291452008-02-04 22:29:38 -08001426 SLOB replaces the stock allocator with a drastically simpler
1427 allocator. SLOB is generally more space efficient but
1428 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001429
1430endchoice
1431
Jie Zhangea637632009-12-14 18:00:02 -08001432config MMAP_ALLOW_UNINITIALIZED
1433 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001434 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001435 default n
1436 help
1437 Normally, and according to the Linux spec, anonymous memory obtained
1438 from mmap() has it's contents cleared before it is passed to
1439 userspace. Enabling this config option allows you to request that
1440 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1441 providing a huge performance boost. If this option is not enabled,
1442 then the flag will be ignored.
1443
1444 This is taken advantage of by uClibc's malloc(), and also by
1445 ELF-FDPIC binfmt's brk and stack allocator.
1446
1447 Because of the obvious security issues, this option should only be
1448 enabled on embedded devices where you control what is run in
1449 userspace. Since that isn't generally a problem on no-MMU systems,
1450 it is normally safe to say Y here.
1451
1452 See Documentation/nommu-mmap.txt for more information.
1453
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001454config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001455 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001456 help
1457 Say Y here to enable the extended profiling support mechanisms used
1458 by profilers such as OProfile.
1459
Ingo Molnar5f87f112008-07-23 14:15:22 +02001460#
1461# Place an empty function call at each tracepoint site. Can be
1462# dynamically changed for a probe function.
1463#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001464config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001465 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001466
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001467source "arch/Kconfig"
1468
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469endmenu # General setup
1470
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001471config HAVE_GENERIC_DMA_COHERENT
1472 bool
1473 default n
1474
Linus Torvalds158a9622008-01-02 13:04:48 -08001475config SLABINFO
1476 bool
1477 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001478 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001479 default y
1480
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001481config RT_MUTEXES
1482 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001483
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484config BASE_SMALL
1485 int
1486 default 0 if BASE_FULL
1487 default 1 if !BASE_FULL
1488
Jan Engelhardt66da5732007-07-15 23:39:29 -07001489menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 bool "Enable loadable module support"
1491 help
1492 Kernel modules are small pieces of compiled code which can
1493 be inserted in the running kernel, rather than being
1494 permanently built into the kernel. You use the "modprobe"
1495 tool to add (and sometimes remove) them. If you say Y here,
1496 many parts of the kernel can be built as modules (by
1497 answering M instead of Y where indicated): this is most
1498 useful for infrequently used options which are not required
1499 for booting. For more information, see the man pages for
1500 modprobe, lsmod, modinfo, insmod and rmmod.
1501
1502 If you say Y here, you will need to run "make
1503 modules_install" to put the modules under /lib/modules/
1504 where modprobe can find them (you may need to be root to do
1505 this).
1506
1507 If unsure, say Y.
1508
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001509if MODULES
1510
Linus Torvalds826e4502008-05-04 17:04:16 -07001511config MODULE_FORCE_LOAD
1512 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001513 default n
1514 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001515 Allow loading of modules without version information (ie. modprobe
1516 --force). Forced module loading sets the 'F' (forced) taint flag and
1517 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001518
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519config MODULE_UNLOAD
1520 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 help
1522 Without this option you will not be able to unload any
1523 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001524 anyway), which makes your kernel smaller, faster
1525 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526
1527config MODULE_FORCE_UNLOAD
1528 bool "Forced module unloading"
1529 depends on MODULE_UNLOAD && EXPERIMENTAL
1530 help
1531 This option allows you to force a module to unload, even if the
1532 kernel believes it is unsafe: the kernel will remove the module
1533 without waiting for anyone to stop using it (using the -f option to
1534 rmmod). This is mainly for kernel developers and desperate users.
1535 If unsure, say N.
1536
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001538 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539 help
1540 Usually, you have to use modules compiled with your kernel.
1541 Saying Y here makes it sometimes possible to use modules
1542 compiled for different kernels, by adding enough information
1543 to the modules to (hopefully) spot any changes which would
1544 make them incompatible with the kernel you are running. If
1545 unsure, say N.
1546
1547config MODULE_SRCVERSION_ALL
1548 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549 help
1550 Modules which contain a MODULE_VERSION get an extra "srcversion"
1551 field inserted into their modinfo section, which contains a
1552 sum of the source files which made it. This helps maintainers
1553 see exactly which source was used to build a module (since
1554 others sometimes change the module source without updating
1555 the version). With this option, such a "srcversion" field
1556 will be created for all modules. If unsure, say N.
1557
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001558endif # MODULES
1559
Rusty Russell98a79d62008-12-13 21:19:41 +10301560config INIT_ALL_POSSIBLE
1561 bool
1562 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301563 Back when each arch used to define their own cpu_online_mask and
1564 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301565 with all 1s, and others with all 0s. When they were centralised,
1566 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001567 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301568
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569config STOP_MACHINE
1570 bool
1571 default y
1572 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1573 help
1574 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001575
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001576source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001577
1578config PREEMPT_NOTIFIERS
1579 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001580
Steffen Klassert16295be2010-01-06 19:47:10 +11001581config PADATA
1582 depends on SMP
1583 bool
1584
Andi Kleen754b7b62012-10-04 17:11:27 -07001585# Can be selected by architectures with broken toolchains
1586# that get confused by correct const<->read_only section
1587# mappings
1588config BROKEN_RODATA
1589 bool
1590
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001591source "kernel/Kconfig.locks"