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Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config HAVE_IRQ_WORK
24 bool
25
26config IRQ_WORK
27 bool
28 depends on HAVE_IRQ_WORK
29
David Daney1dbdc6f2012-04-19 14:59:57 -070030config BUILDTIME_EXTABLE_SORT
31 bool
32
Al Boldiff0cfc62007-07-31 00:39:23 -070033menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35config EXPERIMENTAL
36 bool "Prompt for development and/or incomplete code/drivers"
37 ---help---
38 Some of the various things that Linux supports (such as network
39 drivers, file systems, network protocols, etc.) can be in a state
40 of development where the functionality, stability, or the level of
41 testing is not yet high enough for general use. This is usually
42 known as the "alpha-test" phase among developers. If a feature is
43 currently in alpha-test, then the developers usually discourage
44 uninformed widespread use of this feature by the general public to
45 avoid "Why doesn't this work?" type mail messages. However, active
46 testing and use of these systems is welcomed. Just be aware that it
47 may not meet the normal level of reliability or it may fail to work
48 in some special cases. Detailed bug reports from people familiar
49 with the kernel internals are usually welcomed by the developers
50 (before submitting bug reports, please read the documents
51 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
52 <file:Documentation/BUG-HUNTING>, and
53 <file:Documentation/oops-tracing.txt> in the kernel source).
54
55 This option will also make obsoleted drivers available. These are
56 drivers that have been replaced by something else, and/or are
57 scheduled to be removed in a future kernel release.
58
59 Unless you intend to help test and develop a feature or driver that
60 falls into this category, or you have a situation that requires
61 using these features, you should probably say N here, which will
62 cause the configurator to present you with fewer choices. If
63 you say Y here, you will be offered the choice of using features or
64 drivers that are currently considered to be in the alpha-test phase.
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066config BROKEN
67 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69config BROKEN_ON_SMP
70 bool
71 depends on BROKEN || !SMP
72 default y
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074config INIT_ENV_ARG_LIMIT
75 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070076 default 32 if !UML
77 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080079 Maximum of each of the number of arguments and environment
80 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Roland McGrath84336462009-12-21 16:24:06 -080083config CROSS_COMPILE
84 string "Cross-compiler tool prefix"
85 help
86 Same as running 'make CROSS_COMPILE=prefix-' but stored for
87 default make runs in this kernel build directory. You don't
88 need to set this unless you want the configured kernel build
89 directory to select the cross-compiler automatically.
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091config LOCALVERSION
92 string "Local version - append to kernel release"
93 help
94 Append an extra string to the end of your kernel version.
95 This will show up when you type uname, for example.
96 The string you set here will be appended after the contents of
97 any files with a filename matching localversion* in your
98 object and source tree, in that order. Your total string can
99 be a maximum of 64 characters.
100
Ryan Andersonaaebf432005-07-31 04:57:49 -0400101config LOCALVERSION_AUTO
102 bool "Automatically append version information to the version string"
103 default y
104 help
105 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 release tree by looking for git tags that belong to the current
107 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400108
109 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400111 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200112 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400113
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200114 (The actual string used here is the first eight characters produced
115 by running the command:
116
117 $ git rev-parse --verify HEAD
118
119 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400120
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800121config HAVE_KERNEL_GZIP
122 bool
123
124config HAVE_KERNEL_BZIP2
125 bool
126
127config HAVE_KERNEL_LZMA
128 bool
129
Lasse Collin3ebe1242011-01-12 17:01:23 -0800130config HAVE_KERNEL_XZ
131 bool
132
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800133config HAVE_KERNEL_LZO
134 bool
135
Alain Knaff30d65db2009-01-04 22:46:17 +0100136choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800137 prompt "Kernel compression mode"
138 default KERNEL_GZIP
Lasse Collin3ebe1242011-01-12 17:01:23 -0800139 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800140 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100141 The linux kernel is a kind of self-extracting executable.
142 Several compression algorithms are available, which differ
143 in efficiency, compression and decompression speed.
144 Compression speed is only relevant when building a kernel.
145 Decompression speed is relevant at each boot.
146
147 If you have any problems with bzip2 or lzma compressed
148 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
149 version of this functionality (bzip2 only), for 2.4, was
150 supplied by Christian Ludwig)
151
152 High compression options are mostly useful for users, who
153 are low on disk space (embedded systems), but for whom ram
154 size matters less.
155
156 If in doubt, select 'gzip'
157
158config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800159 bool "Gzip"
160 depends on HAVE_KERNEL_GZIP
161 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800162 The old and tried gzip compression. It provides a good balance
163 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
165config KERNEL_BZIP2
166 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800167 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100168 help
169 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700170 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800171 size is about 10% smaller with bzip2, in comparison to gzip.
172 Bzip2 uses a large amount of memory. For modern kernels you
173 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100174
175config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800176 bool "LZMA"
177 depends on HAVE_KERNEL_LZMA
178 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700179 This compression algorithm's ratio is best. Decompression speed
180 is between gzip and bzip2. Compression is slowest.
181 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100182
Lasse Collin3ebe1242011-01-12 17:01:23 -0800183config KERNEL_XZ
184 bool "XZ"
185 depends on HAVE_KERNEL_XZ
186 help
187 XZ uses the LZMA2 algorithm and instruction set specific
188 BCJ filters which can improve compression ratio of executable
189 code. The size of the kernel is about 30% smaller with XZ in
190 comparison to gzip. On architectures for which there is a BCJ
191 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
192 will create a few percent smaller kernel than plain LZMA.
193
194 The speed is about the same as with LZMA: The decompression
195 speed of XZ is better than that of bzip2 but worse than gzip
196 and LZO. Compression is slow.
197
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800198config KERNEL_LZO
199 bool "LZO"
200 depends on HAVE_KERNEL_LZO
201 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700202 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200203 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800204 (both compression and decompression) is the fastest.
205
Alain Knaff30d65db2009-01-04 22:46:17 +0100206endchoice
207
Josh Triplettbd5dc172011-06-15 15:08:28 -0700208config DEFAULT_HOSTNAME
209 string "Default hostname"
210 default "(none)"
211 help
212 This option determines the default system hostname before userspace
213 calls sethostname(2). The kernel traditionally uses "(none)" here,
214 but you may wish to use a different default here to make a minimal
215 system more usable with less configuration.
216
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217config SWAP
218 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200219 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 default y
221 help
222 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100223 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 used to provide more virtual memory than the actual RAM present
225 in your computer. If unsure say Y.
226
227config SYSVIPC
228 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 ---help---
230 Inter Process Communication is a suite of library functions and
231 system calls which let processes (running programs) synchronize and
232 exchange information. It is generally considered to be a good thing,
233 and some programs won't run unless you say Y here. In particular, if
234 you want to run the DOS emulator dosemu under Linux (read the
235 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
236 you'll need to say Y here.
237
238 You can find documentation about IPC with "info ipc" and also in
239 section 6.4 of the Linux Programmer's Guide, available from
240 <http://www.tldp.org/guides.html>.
241
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800242config SYSVIPC_SYSCTL
243 bool
244 depends on SYSVIPC
245 depends on SYSCTL
246 default y
247
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248config POSIX_MQUEUE
249 bool "POSIX Message Queues"
250 depends on NET && EXPERIMENTAL
251 ---help---
252 POSIX variant of message queues is a part of IPC. In POSIX message
253 queues every message has a priority which decides about succession
254 of receiving it by a process. If you want to compile and run
255 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200256 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 POSIX message queues are visible as a filesystem called 'mqueue'
259 and can be mounted somewhere if you want to do filesystem
260 operations on message queues.
261
262 If unsure, say Y.
263
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700264config POSIX_MQUEUE_SYSCTL
265 bool
266 depends on POSIX_MQUEUE
267 depends on SYSCTL
268 default y
269
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
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700489config RCU_STALL_COMMON
490 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
491 help
492 This option enables RCU CPU stall code that is common between
493 the TINY and TREE variants of RCU. The purpose is to allow
494 the tiny variants to disable RCU CPU stall warnings, while
495 making these warnings mandatory for the tree variants.
496
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100497config CONTEXT_TRACKING
498 bool
499
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200500config RCU_USER_QS
501 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100502 depends on HAVE_CONTEXT_TRACKING && SMP
503 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200504 help
505 This option sets hooks on kernel / userspace boundaries and
506 puts RCU in extended quiescent state when the CPU runs in
507 userspace. It means that when a CPU runs in userspace, it is
508 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700509 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200510
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200511 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100512 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700513 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200514
515 If unsure say N
516
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100517config CONTEXT_TRACKING_FORCE
518 bool "Force context tracking"
519 depends on CONTEXT_TRACKING
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200520 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100521 Probe on user/kernel boundaries by default in order to
522 test the features that rely on it such as userspace RCU extended
523 quiescent states.
524 This test is there for debugging until we have a real user like the
525 full dynticks mode.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200526
Mike Travisc903ff82009-01-15 12:28:29 -0800527config RCU_FANOUT
528 int "Tree-based hierarchical RCU fanout value"
529 range 2 64 if 64BIT
530 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700531 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800532 default 64 if 64BIT
533 default 32 if !64BIT
534 help
535 This option controls the fanout of hierarchical implementations
536 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700537 large numbers of CPUs. This value must be at least the fourth
538 root of NR_CPUS, which allows NR_CPUS to be insanely large.
539 The default value of RCU_FANOUT should be used for production
540 systems, but if you are stress-testing the RCU implementation
541 itself, small RCU_FANOUT values allow you to test large-system
542 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800543
544 Select a specific number if testing RCU itself.
545 Take the default if unsure.
546
Paul E. McKenney8932a632012-04-19 12:20:14 -0700547config RCU_FANOUT_LEAF
548 int "Tree-based hierarchical RCU leaf-level fanout value"
549 range 2 RCU_FANOUT if 64BIT
550 range 2 RCU_FANOUT if !64BIT
551 depends on TREE_RCU || TREE_PREEMPT_RCU
552 default 16
553 help
554 This option controls the leaf-level fanout of hierarchical
555 implementations of RCU, and allows trading off cache misses
556 against lock contention. Systems that synchronize their
557 scheduling-clock interrupts for energy-efficiency reasons will
558 want the default because the smaller leaf-level fanout keeps
559 lock contention levels acceptably low. Very large systems
560 (hundreds or thousands of CPUs) will instead want to set this
561 value to the maximum value possible in order to reduce the
562 number of cache misses incurred during RCU's grace-period
563 initialization. These systems tend to run CPU-bound, and thus
564 are not helped by synchronized interrupts, and thus tend to
565 skew them, which reduces lock contention enough that large
566 leaf-level fanouts work well.
567
568 Select a specific number if testing RCU itself.
569
570 Select the maximum permissible value for large systems.
571
572 Take the default if unsure.
573
Mike Travisc903ff82009-01-15 12:28:29 -0800574config RCU_FANOUT_EXACT
575 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700576 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800577 default n
578 help
579 This option forces use of the exact RCU_FANOUT value specified,
580 regardless of imbalances in the hierarchy. This is useful for
581 testing RCU itself, and might one day be useful on systems with
582 strong NUMA behavior.
583
584 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
585
586 Say N if unsure.
587
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800588config RCU_FAST_NO_HZ
589 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700590 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800591 default n
592 help
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700593 This option causes RCU to attempt to accelerate grace periods in
594 order to allow CPUs to enter dynticks-idle state more quickly.
595 On the other hand, this option increases the overhead of the
596 dynticks-idle checking, thus degrading scheduling latency.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800597
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700598 Say Y if energy efficiency is critically important, and you don't
599 care about real-time response.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800600
601 Say N if you are unsure.
602
Mike Travisc903ff82009-01-15 12:28:29 -0800603config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700604 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800605 select DEBUG_FS
606 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700607 This option provides tracing for the TREE_RCU and
608 TREE_PREEMPT_RCU implementations, permitting Makefile to
609 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800610
Paul E. McKenney24278d12010-09-27 17:25:23 -0700611config RCU_BOOST
612 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800613 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700614 default n
615 help
616 This option boosts the priority of preempted RCU readers that
617 block the current preemptible RCU grace period for too long.
618 This option also prevents heavy loads from blocking RCU
619 callback invocation for all flavors of RCU.
620
621 Say Y here if you are working with real-time apps or heavy loads
622 Say N here if you are unsure.
623
624config RCU_BOOST_PRIO
625 int "Real-time priority to boost RCU readers to"
626 range 1 99
627 depends on RCU_BOOST
628 default 1
629 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700630 This option specifies the real-time priority to which long-term
631 preempted RCU readers are to be boosted. If you are working
632 with a real-time application that has one or more CPU-bound
633 threads running at a real-time priority level, you should set
634 RCU_BOOST_PRIO to a priority higher then the highest-priority
635 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
636 of 1 is appropriate in the common case, which is real-time
637 applications that do not have any CPU-bound threads.
638
639 Some real-time applications might not have a single real-time
640 thread that saturates a given CPU, but instead might have
641 multiple real-time threads that, taken together, fully utilize
642 that CPU. In this case, you should set RCU_BOOST_PRIO to
643 a priority higher than the lowest-priority thread that is
644 conspiring to prevent the CPU from running any non-real-time
645 tasks. For example, if one thread at priority 10 and another
646 thread at priority 5 are between themselves fully consuming
647 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
648 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700649
650 Specify the real-time priority, or take the default if unsure.
651
652config RCU_BOOST_DELAY
653 int "Milliseconds to delay boosting after RCU grace-period start"
654 range 0 3000
655 depends on RCU_BOOST
656 default 500
657 help
658 This option specifies the time to wait after the beginning of
659 a given grace period before priority-boosting preempted RCU
660 readers blocking that grace period. Note that any RCU reader
661 blocking an expedited RCU grace period is boosted immediately.
662
663 Accept the default if unsure.
664
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700665config RCU_NOCB_CPU
666 bool "Offload RCU callback processing from boot-selected CPUs"
667 depends on TREE_RCU || TREE_PREEMPT_RCU
668 default n
669 help
670 Use this option to reduce OS jitter for aggressive HPC or
671 real-time workloads. It can also be used to offload RCU
672 callback invocation to energy-efficient CPUs in battery-powered
673 asymmetric multiprocessors.
674
675 This option offloads callback invocation from the set of
676 CPUs specified at boot time by the rcu_nocbs parameter.
677 For each such CPU, a kthread ("rcuoN") will be created to
678 invoke callbacks, where the "N" is the CPU being offloaded.
679 Nothing prevents this kthread from running on the specified
680 CPUs, but (1) the kthreads may be preempted between each
681 callback, and (2) affinity or cgroups can be used to force
682 the kthreads to run on whatever set of CPUs is desired.
683
684 Say Y here if you want reduced OS jitter on selected CPUs.
685 Say N here if you are unsure.
686
Mike Travisc903ff82009-01-15 12:28:29 -0800687endmenu # "RCU Subsystem"
688
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700690 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 ---help---
692 This option enables the complete Linux kernel ".config" file
693 contents to be saved in the kernel. It provides documentation
694 of which kernel options are used in a running kernel or in an
695 on-disk kernel. This information can be extracted from the kernel
696 image file with the script scripts/extract-ikconfig and used as
697 input to rebuild the current kernel or to build another kernel.
698 It can also be extracted from a running kernel by reading
699 /proc/config.gz if enabled (below).
700
701config IKCONFIG_PROC
702 bool "Enable access to .config through /proc/config.gz"
703 depends on IKCONFIG && PROC_FS
704 ---help---
705 This option enables access to the kernel configuration file
706 through /proc/config.gz.
707
Alistair John Strachan794543a2007-05-08 00:31:15 -0700708config LOG_BUF_SHIFT
709 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
710 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700711 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700712 help
713 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700714 Examples:
715 17 => 128 KB
716 16 => 64 KB
717 15 => 32 KB
718 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700719 13 => 8 KB
720 12 => 4 KB
721
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800722#
723# Architectures with an unreliable sched_clock() should select this:
724#
725config HAVE_UNSTABLE_SCHED_CLOCK
726 bool
727
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200728#
729# For architectures that want to enable the support for NUMA-affine scheduler
730# balancing logic:
731#
732config ARCH_SUPPORTS_NUMA_BALANCING
733 bool
734
735# For architectures that (ab)use NUMA to represent different memory regions
736# all cpu-local but of different latencies, such as SuperH.
737#
738config ARCH_WANT_NUMA_VARIABLE_LOCALITY
739 bool
740
741#
742# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
743config ARCH_WANTS_PROT_NUMA_PROT_NONE
744 bool
745
746config ARCH_USES_NUMA_PROT_NONE
747 bool
748 default y
749 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
750 depends on NUMA_BALANCING
751
Mel Gorman1a687c22012-11-22 11:16:36 +0000752config NUMA_BALANCING_DEFAULT_ENABLED
753 bool "Automatically enable NUMA aware memory/task placement"
754 default y
755 depends on NUMA_BALANCING
756 help
757 If set, autonumic NUMA balancing will be enabled if running on a NUMA
758 machine.
759
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200760config NUMA_BALANCING
761 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200762 depends on ARCH_SUPPORTS_NUMA_BALANCING
763 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
764 depends on SMP && NUMA && MIGRATION
765 help
766 This option adds support for automatic NUMA aware memory/task placement.
767 The mechanism is quite primitive and is based on migrating memory when
768 it is references to the node the task is running on.
769
770 This system will be inactive on UMA systems.
771
Li Zefan23964d22009-01-15 13:50:58 -0800772menuconfig CGROUPS
773 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800774 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700775 help
Li Zefan23964d22009-01-15 13:50:58 -0800776 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800777 use with process control subsystems such as Cpusets, CFS, memory
778 controls or device isolation.
779 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800780 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800781 - Documentation/cgroups/ (features for grouping, isolation
782 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700783
784 Say N if unsure.
785
Li Zefan23964d22009-01-15 13:50:58 -0800786if CGROUPS
787
Paul Menage006cb992007-10-18 23:39:43 -0700788config CGROUP_DEBUG
789 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700790 default n
Paul Menage006cb992007-10-18 23:39:43 -0700791 help
792 This option enables a simple cgroup subsystem that
793 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800794 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700795
Li Zefan23964d22009-01-15 13:50:58 -0800796 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700797
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700798config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800799 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800800 help
801 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700802 cgroup.
803
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700804config CGROUP_DEVICE
805 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700806 help
807 Provides a cgroup implementing whitelists for devices which
808 a process in the cgroup can mknod or open.
809
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810config CPUSETS
811 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700813 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 allow dynamically partitioning a system into sets of CPUs and
815 Memory Nodes and assigning tasks to run only within those sets.
816 This is primarily useful on large SMP or NUMA systems.
817
818 Say N if unsure.
819
Li Zefan23964d22009-01-15 13:50:58 -0800820config PROC_PID_CPUSET
821 bool "Include legacy /proc/<pid>/cpuset file"
822 depends on CPUSETS
823 default y
824
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100825config CGROUP_CPUACCT
826 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100827 help
828 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800829 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100830
Pavel Emelianove552b662008-02-07 00:13:49 -0800831config RESOURCE_COUNTERS
832 bool "Resource counters"
833 help
834 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800835 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800836
Andrew Mortonc255a452012-07-31 16:43:02 -0700837config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800838 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700839 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700840 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800841 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700842 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100843 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800844
845 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700846 associated with each page of memory in the system. By this,
847 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
848 usage tracking struct at boot. Total amount of this is printed out
849 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800850
851 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700852 sure you need the memory resource controller. Even when you enable
853 this, you can set "cgroup_disable=memory" at your boot option to
854 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800855 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800856
Balbir Singhcf475ad2008-04-29 01:00:16 -0700857 This config option also selects MM_OWNER config option, which
858 could in turn add some fork/exit overhead.
859
Andrew Mortonc255a452012-07-31 16:43:02 -0700860config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700861 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700862 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800863 help
864 Add swap management feature to memory resource controller. When you
865 enable this, you can limit mem+swap usage per cgroup. In other words,
866 when you disable this, memory resource controller has no cares to
867 usage of swap...a process can exhaust all of the swap. This extension
868 is useful when you want to avoid exhaustion swap but this itself
869 adds more overheads and consumes memory for remembering information.
870 Especially if you use 32bit system or small memory system, please
871 be careful about enabling this. When memory resource controller
872 is disabled by boot option, this will be automatically disabled and
873 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700874 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700875 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
876 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -0700877config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -0800878 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700879 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800880 default y
881 help
882 Memory Resource Controller Swap Extension comes with its price in
883 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700884 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800885 and let the user enable it by swapaccount boot command line
886 parameter should have this option unselected.
887 For those who want to have the feature enabled by default should
888 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700889 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700890config MEMCG_KMEM
Glauber Costae5671df2011-12-11 21:47:01 +0000891 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
Andrew Mortonc255a452012-07-31 16:43:02 -0700892 depends on MEMCG && EXPERIMENTAL
Glauber Costa510fc4e2012-12-18 14:21:47 -0800893 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +0000894 help
895 The Kernel Memory extension for Memory Resource Controller can limit
896 the amount of memory used by kernel objects in the system. Those are
897 fundamentally different from the entities handled by the standard
898 Memory Controller, which are page-based, and can be swapped. Users of
899 the kmem extension can use it to guarantee that no group of processes
900 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800901
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700902config CGROUP_HUGETLB
903 bool "HugeTLB Resource Controller for Control Groups"
904 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
905 default n
906 help
907 Provides a cgroup Resource Controller for HugeTLB pages.
908 When you enable this, you can put a per cgroup limit on HugeTLB usage.
909 The limit is enforced during page fault. Since HugeTLB doesn't
910 support page reclaim, enforcing the limit at page fault time implies
911 that, the application will get SIGBUS signal if it tries to access
912 HugeTLB pages beyond its limit. This requires the application to know
913 beforehand how much HugeTLB pages it would require for its use. The
914 control group is tracked in the third page lru pointer. This means
915 that we cannot use the controller with huge page less than 3 pages.
916
Stephane Eraniane5d13672011-02-14 11:20:01 +0200917config CGROUP_PERF
918 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
919 depends on PERF_EVENTS && CGROUPS
920 help
921 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800922 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200923 designated cpu.
924
925 Say N if unsure.
926
Dhaval Giani7c941432010-01-20 13:26:18 +0100927menuconfig CGROUP_SCHED
928 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100929 default n
930 help
931 This feature lets CPU scheduler recognize task groups and control CPU
932 bandwidth allocation to such task groups. It uses cgroups to group
933 tasks.
934
935if CGROUP_SCHED
936config FAIR_GROUP_SCHED
937 bool "Group scheduling for SCHED_OTHER"
938 depends on CGROUP_SCHED
939 default CGROUP_SCHED
940
Paul Turnerab84d312011-07-21 09:43:28 -0700941config CFS_BANDWIDTH
942 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
943 depends on EXPERIMENTAL
944 depends on FAIR_GROUP_SCHED
945 default n
946 help
947 This option allows users to define CPU bandwidth rates (limits) for
948 tasks running within the fair group scheduler. Groups with no limit
949 set are considered to be unconstrained and will run with no
950 restriction.
951 See tip/Documentation/scheduler/sched-bwc.txt for more information.
952
Dhaval Giani7c941432010-01-20 13:26:18 +0100953config RT_GROUP_SCHED
954 bool "Group scheduling for SCHED_RR/FIFO"
955 depends on EXPERIMENTAL
956 depends on CGROUP_SCHED
957 default n
958 help
959 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800960 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100961 schedule realtime tasks for non-root users until you allocate
962 realtime bandwidth for them.
963 See Documentation/scheduler/sched-rt-group.txt for more information.
964
965endif #CGROUP_SCHED
966
Vivek Goyalafc24d42010-04-26 19:27:56 +0200967config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -0800968 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700969 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200970 default n
971 ---help---
972 Generic block IO controller cgroup interface. This is the common
973 cgroup interface which should be used by various IO controlling
974 policies.
975
976 Currently, CFQ IO scheduler uses it to recognize task groups and
977 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400978 to such task groups. It is also used by bio throttling logic in
979 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200980
981 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400982 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000983 enabling proportional weight division of disk bandwidth in CFQ, set
984 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000985 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200986
987 See Documentation/cgroups/blkio-controller.txt for more information.
988
989config DEBUG_BLK_CGROUP
990 bool "Enable Block IO controller debugging"
991 depends on BLK_CGROUP
992 default n
993 ---help---
994 Enable some debugging help. Currently it exports additional stat
995 files in a cgroup which can be useful for debugging.
996
Li Zefan23964d22009-01-15 13:50:58 -0800997endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800998
Cyrill Gorcunov067bce12012-01-12 17:20:49 -0800999config CHECKPOINT_RESTORE
1000 bool "Checkpoint/restore support" if EXPERT
1001 default n
1002 help
1003 Enables additional kernel features in a sake of checkpoint/restore.
1004 In particular it adds auxiliary prctl codes to setup process text,
1005 data and heap segment sizes, and a few additional /proc filesystem
1006 entries.
1007
1008 If unsure, say N here.
1009
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001010menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001011 bool "Namespaces support" if EXPERT
1012 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001013 help
1014 Provides the way to make tasks work with different objects using
1015 the same id. For example same IPC id may refer to different objects
1016 or same user id or pid may refer to different tasks when used in
1017 different namespaces.
1018
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001019if NAMESPACES
1020
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001021config UTS_NS
1022 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001023 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001024 help
1025 In this namespace tasks see different info provided with the
1026 uname() system call
1027
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001028config IPC_NS
1029 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001030 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001031 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001032 help
1033 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001034 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001035
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001036config USER_NS
1037 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001038 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001039 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001040 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001041
Eric W. Biederman5673a942011-11-17 10:23:55 -08001042 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001043 help
1044 This allows containers, i.e. vservers, to use user namespaces
1045 to provide different user info for different servers.
1046 If unsure, say N.
1047
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001048config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001049 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001050 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001051 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001052 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001053 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001054 pid namespaces. This is a building block of containers.
1055
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001056config NET_NS
1057 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001058 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001059 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001060 help
1061 Allow user space to create what appear to be multiple instances
1062 of the network stack.
1063
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001064endif # NAMESPACES
1065
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001066config UIDGID_CONVERTED
1067 # True if all of the selected software conmponents are known
1068 # to have uid_t and gid_t converted to kuid_t and kgid_t
1069 # where appropriate and are otherwise safe to use with
1070 # the user namespace.
1071 bool
1072 default y
1073
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001074 # Networking
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001075 depends on NET_9P = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001076
1077 # Filesystems
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001078 depends on 9P_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001079 depends on AFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001080 depends on CEPH_FS = n
1081 depends on CIFS = n
1082 depends on CODA_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001083 depends on GFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001084 depends on NCP_FS = n
1085 depends on NFSD = n
1086 depends on NFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001087 depends on OCFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001088 depends on XFS_FS = n
1089
Eric W. Biederman5673a942011-11-17 10:23:55 -08001090config UIDGID_STRICT_TYPE_CHECKS
1091 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001092 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001093 default n
1094 help
1095 While the nececessary conversions are being added to all subsystems this option allows
1096 the code to continue to build for unconverted subsystems.
1097
1098 Say Y here if you want the strict type checking enabled
1099
Mike Galbraith5091faa2010-11-30 14:18:03 +01001100config SCHED_AUTOGROUP
1101 bool "Automatic process group scheduling"
1102 select EVENTFD
1103 select CGROUPS
1104 select CGROUP_SCHED
1105 select FAIR_GROUP_SCHED
1106 help
1107 This option optimizes the scheduler for common desktop workloads by
1108 automatically creating and populating task groups. This separation
1109 of workloads isolates aggressive CPU burners (like build jobs) from
1110 desktop applications. Task group autogeneration is currently based
1111 upon task session.
1112
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001113config MM_OWNER
1114 bool
1115
1116config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001117 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001118 depends on SYSFS
1119 default n
1120 help
1121 This option adds code that switches the layout of the "block" class
1122 devices, to not show up in /sys/class/block/, but only in
1123 /sys/block/.
1124
1125 This switch is only active when the sysfs.deprecated=1 boot option is
1126 passed or the SYSFS_DEPRECATED_V2 option is set.
1127
1128 This option allows new kernels to run on old distributions and tools,
1129 which might get confused by /sys/class/block/. Since 2007/2008 all
1130 major distributions and tools handle this just fine.
1131
1132 Recent distributions and userspace tools after 2009/2010 depend on
1133 the existence of /sys/class/block/, and will not work with this
1134 option enabled.
1135
1136 Only if you are using a new kernel on an old distribution, you might
1137 need to say Y here.
1138
1139config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001140 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001141 default n
1142 depends on SYSFS
1143 depends on SYSFS_DEPRECATED
1144 help
1145 Enable deprecated sysfs by default.
1146
1147 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1148 option.
1149
1150 Only if you are using a new kernel on an old distribution, you might
1151 need to say Y here. Even then, odds are you would not need it
1152 enabled, you can always pass the boot option if absolutely necessary.
1153
1154config RELAY
1155 bool "Kernel->user space relay support (formerly relayfs)"
1156 help
1157 This option enables support for relay interface support in
1158 certain file systems (such as debugfs).
1159 It is designed to provide an efficient mechanism for tools and
1160 facilities to relay large amounts of data from kernel space to
1161 user space.
1162
1163 If unsure, say N.
1164
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001165config BLK_DEV_INITRD
1166 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1167 depends on BROKEN || !FRV
1168 help
1169 The initial RAM filesystem is a ramfs which is loaded by the
1170 boot loader (loadlin or lilo) and that is mounted as root
1171 before the normal boot procedure. It is typically used to
1172 load modules needed to mount the "real" root file system,
1173 etc. See <file:Documentation/initrd.txt> for details.
1174
1175 If RAM disk support (BLK_DEV_RAM) is also included, this
1176 also enables initial RAM disk (initrd) support and adds
1177 15 Kbytes (more on some other architectures) to the kernel size.
1178
1179 If unsure say Y.
1180
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001181if BLK_DEV_INITRD
1182
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001183source "usr/Kconfig"
1184
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001185endif
1186
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001187config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001188 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001189 help
1190 Enabling this option will pass "-Os" instead of "-O2" to gcc
1191 resulting in a smaller kernel.
1192
jkacur775a7222008-07-16 00:31:16 +02001193 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001194
Randy Dunlap08470622006-09-30 23:28:13 -07001195config SYSCTL
1196 bool
1197
Randy Dunlapb943c462009-03-10 12:55:46 -07001198config ANON_INODES
1199 bool
1200
David Rientjes6a108a12011-01-20 14:44:16 -08001201menuconfig EXPERT
1202 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001203 # Unhide debug options, to make the on-by-default options visible
1204 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 help
1206 This option allows certain base kernel options and settings
1207 to be disabled or tweaked. This is for specialized
1208 environments which can tolerate a "non-standard" kernel.
1209 Only use this if you really know what you are doing.
1210
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001211config HAVE_UID16
1212 bool
1213
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001214config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001215 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001216 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001217 default y
1218 help
1219 This enables the legacy 16-bit UID syscall wrappers.
1220
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001221config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001222 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001223 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001224 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001225 select SYSCTL
1226 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001227 sys_sysctl uses binary paths that have been found challenging
1228 to properly maintain and use. The interface in /proc/sys
1229 using paths with ascii names is now the primary path to this
1230 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001231
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001232 Almost nothing using the binary sysctl interface so if you are
1233 trying to save some space it is probably safe to disable this,
1234 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001235
WANG Congc736de62011-11-02 13:39:25 -07001236 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001237
Catalin Marinas7ac57a82012-10-08 16:28:16 -07001238config SYSCTL_EXCEPTION_TRACE
1239 bool
1240 help
1241 Enable support for /proc/sys/debug/exception-trace.
1242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001244 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 default y
1246 help
1247 Say Y here to let the kernel print out symbolic crash information and
1248 symbolic stack backtraces. This increases the size of the kernel
1249 somewhat, as all symbols have to be loaded into the kernel image.
1250
1251config KALLSYMS_ALL
1252 bool "Include all symbols in kallsyms"
1253 depends on DEBUG_KERNEL && KALLSYMS
1254 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001255 Normally kallsyms only contains the symbols of functions for nicer
1256 OOPS messages and backtraces (i.e., symbols from the text and inittext
1257 sections). This is sufficient for most cases. And only in very rare
1258 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1259 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001261 This option makes sure that all symbols are loaded into the kernel
1262 image (i.e., symbols from all sections) in cost of increased kernel
1263 size (depending on the kernel configuration, it may be 300KiB or
1264 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001266 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001267
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001268config HOTPLUG
Greg Kroah-Hartman45f035a2012-09-04 17:01:08 -07001269 def_bool y
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001270
Matt Mackalld59745c2005-05-01 08:59:02 -07001271config PRINTK
1272 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001273 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001274 help
1275 This option enables normal printk support. Removing it
1276 eliminates most of the message strings from the kernel image
1277 and makes the kernel more or less silent. As this makes it
1278 very difficult to diagnose system problems, saying N here is
1279 strongly discouraged.
1280
Matt Mackallc8538a72005-05-01 08:59:01 -07001281config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001282 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001283 default y
1284 help
1285 Disabling this option eliminates support for BUG and WARN, reducing
1286 the size of your kernel image and potentially quietly ignoring
1287 numerous fatal conditions. You should only consider disabling this
1288 option for embedded systems with no facilities for reporting errors.
1289 Just say Y.
1290
Matt Mackall708e9a72006-01-08 01:05:25 -08001291config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001292 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001293 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001294 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001295 help
1296 Enable support for generating core dumps. Disabling saves about 4k.
1297
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001298
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001299config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001300 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001301 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001302 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001303 default y
1304 help
1305 This option allows to disable the internal PC-Speaker
1306 support, saving some memory.
1307
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001308config HAVE_PCSPKR_PLATFORM
1309 bool
1310
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311config BASE_FULL
1312 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001313 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 help
1315 Disabling this option reduces the size of miscellaneous core
1316 kernel data structures. This saves memory on small machines,
1317 but may reduce performance.
1318
1319config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001320 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001322 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 help
1324 Disabling this option will cause the kernel to be built without
1325 support for "fast userspace mutexes". The resulting kernel may not
1326 run glibc-based applications correctly.
1327
1328config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001329 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001331 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 help
1333 Disabling this option will cause the kernel to be built without
1334 support for epoll family of system calls.
1335
Davide Libenzifba2afa2007-05-10 22:23:13 -07001336config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001337 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001338 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001339 default y
1340 help
1341 Enable the signalfd() system call that allows to receive signals
1342 on a file descriptor.
1343
1344 If unsure, say Y.
1345
Davide Libenzib215e282007-05-10 22:23:16 -07001346config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001347 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001348 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001349 default y
1350 help
1351 Enable the timerfd() system call that allows to receive timer
1352 events on a file descriptor.
1353
1354 If unsure, say Y.
1355
Davide Libenzie1ad7462007-05-10 22:23:19 -07001356config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001357 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001358 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001359 default y
1360 help
1361 Enable the eventfd() system call that allows to receive both
1362 kernel notification (ie. KAIO) or userspace notifications.
1363
1364 If unsure, say Y.
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001367 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 default y
1369 depends on MMU
1370 help
1371 The shmem is an internal filesystem used to manage shared memory.
1372 It is backed by swap and manages resource limits. It is also exported
1373 to userspace as tmpfs if TMPFS is enabled. Disabling this
1374 option replaces shmem and tmpfs with the much simpler ramfs code,
1375 which may be appropriate on small systems without swap.
1376
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001377config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001378 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001379 default y
1380 help
1381 This option enables POSIX asynchronous I/O which may by used
1382 by some high performance threaded applications. Disabling
1383 this option saves about 7k.
1384
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001385config EMBEDDED
1386 bool "Embedded system"
1387 select EXPERT
1388 help
1389 This option should be enabled if compiling the kernel for
1390 an embedded system so certain expert options are available
1391 for configuration.
1392
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001393config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001394 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001395 help
1396 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001397
Peter Zijlstra906010b2009-09-21 16:08:49 +02001398config PERF_USE_VMALLOC
1399 bool
1400 help
1401 See tools/perf/design.txt for details
1402
Ingo Molnar57c0c152009-09-21 12:20:38 +02001403menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001404
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001405config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001406 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001407 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001408 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001409 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001410 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001411 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001412 Enable kernel support for various performance events provided
1413 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001414
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001415 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001416 use of generic tracepoints.
1417
1418 Most modern CPUs support performance events via performance
1419 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001420 types of hw events: such as instructions executed, cachemisses
1421 suffered, or branches mis-predicted - without slowing down the
1422 kernel or applications. These registers can also trigger interrupts
1423 when a threshold number of events have passed - and can thus be
1424 used to profile the code that runs on that CPU.
1425
Ingo Molnar57c0c152009-09-21 12:20:38 +02001426 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001427 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001428 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001429 provides per task and per CPU counters, and it provides event
1430 capabilities on top of those.
1431
1432 Say Y if unsure.
1433
Peter Zijlstra906010b2009-09-21 16:08:49 +02001434config DEBUG_PERF_USE_VMALLOC
1435 default n
1436 bool "Debug: use vmalloc to back perf mmap() buffers"
1437 depends on PERF_EVENTS && DEBUG_KERNEL
1438 select PERF_USE_VMALLOC
1439 help
1440 Use vmalloc memory to back perf mmap() buffers.
1441
1442 Mostly useful for debugging the vmalloc code on platforms
1443 that don't require it.
1444
1445 Say N if unsure.
1446
Thomas Gleixner0793a612008-12-04 20:12:29 +01001447endmenu
1448
Christoph Lameterf8891e52006-06-30 01:55:45 -07001449config VM_EVENT_COUNTERS
1450 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001451 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001452 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001453 VM event counters are needed for event counts to be shown.
1454 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001455 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001456 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001457
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001458config PCI_QUIRKS
1459 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001460 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001461 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001462 help
1463 This enables workarounds for various PCI chipset
1464 bugs/quirks. Disable this only if your target machine is
1465 unaffected by PCI quirks.
1466
Christoph Lameter41ecc552007-05-09 02:32:44 -07001467config SLUB_DEBUG
1468 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001469 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001470 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001471 help
1472 SLUB has extensive debug support features. Disabling these can
1473 result in significant savings in code size. This also disables
1474 SLUB sysfs support. /sys/slab will not exist and there will be
1475 no support for cache validation etc.
1476
Randy Dunlapb943c462009-03-10 12:55:46 -07001477config COMPAT_BRK
1478 bool "Disable heap randomization"
1479 default y
1480 help
1481 Randomizing heap placement makes heap exploits harder, but it
1482 also breaks ancient binaries (including anything libc5 based).
1483 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001484 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001485 /proc/sys/kernel/randomize_va_space to 2.
1486
1487 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1488
Christoph Lameter81819f02007-05-06 14:49:36 -07001489choice
1490 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001491 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001492 help
1493 This option allows to select a slab allocator.
1494
1495config SLAB
1496 bool "SLAB"
1497 help
1498 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001499 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001500 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001501
1502config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001503 bool "SLUB (Unqueued Allocator)"
1504 help
1505 SLUB is a slab allocator that minimizes cache line usage
1506 instead of managing queues of cached objects (SLAB approach).
1507 Per cpu caching is realized using slabs of objects instead
1508 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001509 and has enhanced diagnostics. SLUB is the default choice for
1510 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001511
1512config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001513 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001514 bool "SLOB (Simple Allocator)"
1515 help
Matt Mackall37291452008-02-04 22:29:38 -08001516 SLOB replaces the stock allocator with a drastically simpler
1517 allocator. SLOB is generally more space efficient but
1518 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001519
1520endchoice
1521
Jie Zhangea637632009-12-14 18:00:02 -08001522config MMAP_ALLOW_UNINITIALIZED
1523 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001524 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001525 default n
1526 help
1527 Normally, and according to the Linux spec, anonymous memory obtained
1528 from mmap() has it's contents cleared before it is passed to
1529 userspace. Enabling this config option allows you to request that
1530 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1531 providing a huge performance boost. If this option is not enabled,
1532 then the flag will be ignored.
1533
1534 This is taken advantage of by uClibc's malloc(), and also by
1535 ELF-FDPIC binfmt's brk and stack allocator.
1536
1537 Because of the obvious security issues, this option should only be
1538 enabled on embedded devices where you control what is run in
1539 userspace. Since that isn't generally a problem on no-MMU systems,
1540 it is normally safe to say Y here.
1541
1542 See Documentation/nommu-mmap.txt for more information.
1543
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001544config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001545 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001546 help
1547 Say Y here to enable the extended profiling support mechanisms used
1548 by profilers such as OProfile.
1549
Ingo Molnar5f87f112008-07-23 14:15:22 +02001550#
1551# Place an empty function call at each tracepoint site. Can be
1552# dynamically changed for a probe function.
1553#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001554config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001555 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001556
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001557source "arch/Kconfig"
1558
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559endmenu # General setup
1560
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001561config HAVE_GENERIC_DMA_COHERENT
1562 bool
1563 default n
1564
Linus Torvalds158a9622008-01-02 13:04:48 -08001565config SLABINFO
1566 bool
1567 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001568 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001569 default y
1570
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001571config RT_MUTEXES
1572 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001573
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574config BASE_SMALL
1575 int
1576 default 0 if BASE_FULL
1577 default 1 if !BASE_FULL
1578
Jan Engelhardt66da5732007-07-15 23:39:29 -07001579menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580 bool "Enable loadable module support"
1581 help
1582 Kernel modules are small pieces of compiled code which can
1583 be inserted in the running kernel, rather than being
1584 permanently built into the kernel. You use the "modprobe"
1585 tool to add (and sometimes remove) them. If you say Y here,
1586 many parts of the kernel can be built as modules (by
1587 answering M instead of Y where indicated): this is most
1588 useful for infrequently used options which are not required
1589 for booting. For more information, see the man pages for
1590 modprobe, lsmod, modinfo, insmod and rmmod.
1591
1592 If you say Y here, you will need to run "make
1593 modules_install" to put the modules under /lib/modules/
1594 where modprobe can find them (you may need to be root to do
1595 this).
1596
1597 If unsure, say Y.
1598
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001599if MODULES
1600
Linus Torvalds826e4502008-05-04 17:04:16 -07001601config MODULE_FORCE_LOAD
1602 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001603 default n
1604 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001605 Allow loading of modules without version information (ie. modprobe
1606 --force). Forced module loading sets the 'F' (forced) taint flag and
1607 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001608
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609config MODULE_UNLOAD
1610 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611 help
1612 Without this option you will not be able to unload any
1613 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001614 anyway), which makes your kernel smaller, faster
1615 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616
1617config MODULE_FORCE_UNLOAD
1618 bool "Forced module unloading"
1619 depends on MODULE_UNLOAD && EXPERIMENTAL
1620 help
1621 This option allows you to force a module to unload, even if the
1622 kernel believes it is unsafe: the kernel will remove the module
1623 without waiting for anyone to stop using it (using the -f option to
1624 rmmod). This is mainly for kernel developers and desperate users.
1625 If unsure, say N.
1626
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001628 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 help
1630 Usually, you have to use modules compiled with your kernel.
1631 Saying Y here makes it sometimes possible to use modules
1632 compiled for different kernels, by adding enough information
1633 to the modules to (hopefully) spot any changes which would
1634 make them incompatible with the kernel you are running. If
1635 unsure, say N.
1636
1637config MODULE_SRCVERSION_ALL
1638 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639 help
1640 Modules which contain a MODULE_VERSION get an extra "srcversion"
1641 field inserted into their modinfo section, which contains a
1642 sum of the source files which made it. This helps maintainers
1643 see exactly which source was used to build a module (since
1644 others sometimes change the module source without updating
1645 the version). With this option, such a "srcversion" field
1646 will be created for all modules. If unsure, say N.
1647
Rusty Russell106a4ee2012-09-26 10:09:40 +01001648config MODULE_SIG
1649 bool "Module signature verification"
1650 depends on MODULES
David Howells48ba2462012-09-26 10:11:03 +01001651 select KEYS
1652 select CRYPTO
1653 select ASYMMETRIC_KEY_TYPE
1654 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1655 select PUBLIC_KEY_ALGO_RSA
1656 select ASN1
1657 select OID_REGISTRY
1658 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001659 help
1660 Check modules for valid signatures upon load: the signature
1661 is simply appended to the module. For more information see
1662 Documentation/module-signing.txt.
1663
David Howellsea0b6dc2012-09-26 10:09:50 +01001664 !!!WARNING!!! If you enable this option, you MUST make sure that the
1665 module DOES NOT get stripped after being signed. This includes the
1666 debuginfo strip done by some packagers (such as rpmbuild) and
1667 inclusion into an initramfs that wants the module size reduced.
1668
Rusty Russell106a4ee2012-09-26 10:09:40 +01001669config MODULE_SIG_FORCE
1670 bool "Require modules to be validly signed"
1671 depends on MODULE_SIG
1672 help
1673 Reject unsigned modules or signed modules for which we don't have a
1674 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001675
1676choice
1677 prompt "Which hash algorithm should modules be signed with?"
1678 depends on MODULE_SIG
1679 help
1680 This determines which sort of hashing algorithm will be used during
1681 signature generation. This algorithm _must_ be built into the kernel
1682 directly so that signature verification can take place. It is not
1683 possible to load a signed module containing the algorithm to check
1684 the signature on that module.
1685
1686config MODULE_SIG_SHA1
1687 bool "Sign modules with SHA-1"
1688 select CRYPTO_SHA1
1689
1690config MODULE_SIG_SHA224
1691 bool "Sign modules with SHA-224"
1692 select CRYPTO_SHA256
1693
1694config MODULE_SIG_SHA256
1695 bool "Sign modules with SHA-256"
1696 select CRYPTO_SHA256
1697
1698config MODULE_SIG_SHA384
1699 bool "Sign modules with SHA-384"
1700 select CRYPTO_SHA512
1701
1702config MODULE_SIG_SHA512
1703 bool "Sign modules with SHA-512"
1704 select CRYPTO_SHA512
1705
1706endchoice
1707
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001708endif # MODULES
1709
Rusty Russell98a79d62008-12-13 21:19:41 +10301710config INIT_ALL_POSSIBLE
1711 bool
1712 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301713 Back when each arch used to define their own cpu_online_mask and
1714 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301715 with all 1s, and others with all 0s. When they were centralised,
1716 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001717 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301718
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719config STOP_MACHINE
1720 bool
1721 default y
1722 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1723 help
1724 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001725
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001726source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001727
1728config PREEMPT_NOTIFIERS
1729 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001730
Steffen Klassert16295be2010-01-06 19:47:10 +11001731config PADATA
1732 depends on SMP
1733 bool
1734
Andi Kleen754b7b62012-10-04 17:11:27 -07001735# Can be selected by architectures with broken toolchains
1736# that get confused by correct const<->read_only section
1737# mappings
1738config BROKEN_RODATA
1739 bool
1740
David Howells4520c6a2012-09-21 23:31:13 +01001741config ASN1
1742 tristate
1743 help
1744 Build a simple ASN.1 grammar compiler that produces a bytecode output
1745 that can be interpreted by the ASN.1 stream decoder and used to
1746 inform it as to what tags are to be expected in a stream and what
1747 functions to call on what tags.
1748
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001749source "kernel/Kconfig.locks"