blob: a291b7ef473893891481f188b81f7dfce1550942 [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 IRQ_WORK
24 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +080025
David Daney1dbdc6f2012-04-19 14:59:57 -070026config BUILDTIME_EXTABLE_SORT
27 bool
28
Al Boldiff0cfc62007-07-31 00:39:23 -070029menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031config BROKEN
32 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34config BROKEN_ON_SMP
35 bool
36 depends on BROKEN || !SMP
37 default y
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config INIT_ENV_ARG_LIMIT
40 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070041 default 32 if !UML
42 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080044 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Roland McGrath84336462009-12-21 16:24:06 -080048config CROSS_COMPILE
49 string "Cross-compiler tool prefix"
50 help
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically.
55
Jiri Slaby4bb16672013-05-22 10:56:24 +020056config COMPILE_TEST
57 bool "Compile also drivers which will not load"
58 default n
59 help
60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them.
65
66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed.
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070config LOCALVERSION
71 string "Local version - append to kernel release"
72 help
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
79
Ryan Andersonaaebf432005-07-31 04:57:49 -040080config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
82 default y
83 help
84 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020085 release tree by looking for git tags that belong to the current
86 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040087
88 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020089 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040090 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020091 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -040092
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020093 (The actual string used here is the first eight characters produced
94 by running the command:
95
96 $ git rev-parse --verify HEAD
97
98 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -040099
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800100config HAVE_KERNEL_GZIP
101 bool
102
103config HAVE_KERNEL_BZIP2
104 bool
105
106config HAVE_KERNEL_LZMA
107 bool
108
Lasse Collin3ebe1242011-01-12 17:01:23 -0800109config HAVE_KERNEL_XZ
110 bool
111
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800112config HAVE_KERNEL_LZO
113 bool
114
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700115config HAVE_KERNEL_LZ4
116 bool
117
Alain Knaff30d65db2009-01-04 22:46:17 +0100118choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800119 prompt "Kernel compression mode"
120 default KERNEL_GZIP
H. Peter Anvin2d3c6272013-11-14 21:43:47 -0800121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800122 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot.
128
129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig)
133
134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram
136 size matters less.
137
138 If in doubt, select 'gzip'
139
140config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800141 bool "Gzip"
142 depends on HAVE_KERNEL_GZIP
143 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100146
147config KERNEL_BZIP2
148 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800149 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100150 help
151 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700152 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100156
157config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800158 bool "LZMA"
159 depends on HAVE_KERNEL_LZMA
160 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
Lasse Collin3ebe1242011-01-12 17:01:23 -0800165config KERNEL_XZ
166 bool "XZ"
167 depends on HAVE_KERNEL_XZ
168 help
169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA.
175
176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow.
179
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800180config KERNEL_LZO
181 bool "LZO"
182 depends on HAVE_KERNEL_LZO
183 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700184 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200185 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800186 (both compression and decompression) is the fastest.
187
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700188config KERNEL_LZ4
189 bool "LZ4"
190 depends on HAVE_KERNEL_LZ4
191 help
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>.
195
196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is
198 faster than LZO.
199
Alain Knaff30d65db2009-01-04 22:46:17 +0100200endchoice
201
Josh Triplettbd5dc172011-06-15 15:08:28 -0700202config DEFAULT_HOSTNAME
203 string "Default hostname"
204 default "(none)"
205 help
206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration.
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211config SWAP
212 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200213 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 default y
215 help
216 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100217 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y.
220
221config SYSVIPC
222 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 ---help---
224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here.
231
232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>.
235
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800236config SYSVIPC_SYSCTL
237 bool
238 depends on SYSVIPC
239 depends on SYSCTL
240 default y
241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242config POSIX_MQUEUE
243 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700244 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 ---help---
246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200250 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues.
255
256 If unsure, say Y.
257
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700258config POSIX_MQUEUE_SYSCTL
259 bool
260 depends on POSIX_MQUEUE
261 depends on SYSCTL
262 default y
263
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700264config CROSS_MEMORY_ATTACH
265 bool "Enable process_vm_readv/writev syscalls"
266 depends on MMU
267 default y
268 help
269 Enabling this option adds the system calls process_vm_readv and
270 process_vm_writev which allow a process with the correct privileges
271 to directly read from or write to to another process's address space.
272 See the man page for more details.
273
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530274config FHANDLE
275 bool "open by fhandle syscalls"
276 select EXPORTFS
277 help
278 If you say Y here, a user level program will be able to map
279 file names to handle and then later use the handle for
280 different file system operations. This is useful in implementing
281 userspace file servers, which now track files using handles instead
282 of names. The handle would remain the same even if file names
283 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
284 syscalls.
285
Josh Triplett69369a72014-04-03 14:48:27 -0700286config USELIB
287 bool "uselib syscall"
288 default y
289 help
290 This option enables the uselib syscall, a system call used in the
291 dynamic linker from libc5 and earlier. glibc does not use this
292 system call. If you intend to run programs built on libc5 or
293 earlier, you may need to enable this syscall. Current systems
294 running glibc can safely disable this.
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296config AUDIT
297 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100298 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 help
300 Enable auditing infrastructure that can be used with another
301 kernel subsystem, such as SELinux (which requires this for
302 logging of avc messages output). Does not do system-call
303 auditing without CONFIG_AUDITSYSCALL.
304
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900305config HAVE_ARCH_AUDITSYSCALL
306 bool
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308config AUDITSYSCALL
309 bool "Enable system-call auditing support"
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 default y if SECURITY_SELINUX
312 help
313 Enable low-overhead system-call auditing infrastructure that
314 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500315 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Eric Paris939a67f2009-12-17 20:12:06 -0500317config AUDIT_WATCH
318 def_bool y
319 depends on AUDITSYSCALL
320 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Al Viro74c3cbe2007-07-22 08:04:18 -0400322config AUDIT_TREE
323 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400324 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500325 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400326
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000327source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200328source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000329
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200330menu "CPU/Task time and stats accounting"
331
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200332config VIRT_CPU_ACCOUNTING
333 bool
334
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200335choice
336 prompt "Cputime accounting"
337 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100338 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200339
340# Kind of a stub config for the pure tick based cputime accounting
341config TICK_CPU_ACCOUNTING
342 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200343 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200344 help
345 This is the basic tick based cputime accounting that maintains
346 statistics about user, system and idle time spent on per jiffies
347 granularity.
348
349 If unsure, say Y.
350
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200351config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200352 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200353 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200354 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200355 help
356 Select this option to enable more accurate task and CPU time
357 accounting. This is done by reading a CPU counter on each
358 kernel entry and exit and on transitions within the kernel
359 between system, softirq and hardirq state, so there is a
360 small performance impact. In the case of s390 or IBM POWER > 5,
361 this also enables accounting of stolen time on logically-partitioned
362 systems.
363
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200364config VIRT_CPU_ACCOUNTING_GEN
365 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700366 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700367 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200368 select VIRT_CPU_ACCOUNTING
369 select CONTEXT_TRACKING
370 help
371 Select this option to enable task and CPU time accounting on full
372 dynticks systems. This accounting is implemented by watching every
373 kernel-user boundaries using the context tracking subsystem.
374 The accounting is thus performed at the expense of some significant
375 overhead.
376
377 For now this is only useful if you are working on the full
378 dynticks subsystem development.
379
380 If unsure, say N.
381
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200382config IRQ_TIME_ACCOUNTING
383 bool "Fine granularity task level IRQ time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200384 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200385 help
386 Select this option to enable fine granularity task irq time
387 accounting. This is done by reading a timestamp on each
388 transitions between softirq and hardirq state, so there can be a
389 small performance impact.
390
391 If in doubt, say N here.
392
393endchoice
394
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200395config BSD_PROCESS_ACCT
396 bool "BSD Process Accounting"
397 help
398 If you say Y here, a user level program will be able to instruct the
399 kernel (via a special system call) to write process accounting
400 information to a file: whenever a process exits, information about
401 that process will be appended to the file by the kernel. The
402 information includes things such as creation time, owning user,
403 command name, memory usage, controlling terminal etc. (the complete
404 list is in the struct acct in <file:include/linux/acct.h>). It is
405 up to the user level program to do useful things with this
406 information. This is generally a good idea, so say Y.
407
408config BSD_PROCESS_ACCT_V3
409 bool "BSD Process Accounting version 3 file format"
410 depends on BSD_PROCESS_ACCT
411 default n
412 help
413 If you say Y here, the process accounting information is written
414 in a new file format that also logs the process IDs of each
415 process and it's parent. Note that this file format is incompatible
416 with previous v0/v1/v2 file formats, so you will need updated tools
417 for processing it. A preliminary version of these tools is available
418 at <http://www.gnu.org/software/acct/>.
419
420config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700421 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200422 depends on NET
423 default n
424 help
425 Export selected statistics for tasks/processes through the
426 generic netlink interface. Unlike BSD process accounting, the
427 statistics are available during the lifetime of tasks/processes as
428 responses to commands. Like BSD accounting, they are sent to user
429 space on task exit.
430
431 Say N if unsure.
432
433config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700434 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200435 depends on TASKSTATS
436 help
437 Collect information on time spent by a task waiting for system
438 resources like cpu, synchronous block I/O completion and swapping
439 in pages. Such statistics can help in setting a task's priorities
440 relative to other tasks for cpu, io, rss limits etc.
441
442 Say N if unsure.
443
444config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700445 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200446 depends on TASKSTATS
447 help
448 Collect extended task accounting data and send the data
449 to userland for processing over the taskstats interface.
450
451 Say N if unsure.
452
453config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700454 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200455 depends on TASK_XACCT
456 help
457 Collect information on the number of bytes of storage I/O which this
458 task has caused.
459
460 Say N if unsure.
461
462endmenu # "CPU/Task time and stats accounting"
463
Mike Travisc903ff82009-01-15 12:28:29 -0800464menu "RCU Subsystem"
465
466choice
467 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700468 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800469
Mike Travisc903ff82009-01-15 12:28:29 -0800470config TREE_RCU
471 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700472 depends on !PREEMPT && SMP
Steven Rostedt016a8d52013-05-28 17:32:53 -0400473 select IRQ_WORK
Mike Travisc903ff82009-01-15 12:28:29 -0800474 help
475 This option selects the RCU implementation that is
476 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700477 thousands of CPUs. It also scales down nicely to
478 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800479
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700480config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700481 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800482 depends on PREEMPT
James Hogan53614712013-07-25 15:34:25 +0100483 select IRQ_WORK
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700484 help
485 This option selects the RCU implementation that is
486 designed for very large SMP systems with hundreds or
487 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700488 is also required. It also scales down nicely to
489 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700490
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800491 Select this option if you are unsure.
492
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700493config TINY_RCU
494 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700495 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700496 help
497 This option selects the RCU implementation that is
498 designed for UP systems from which real-time response
499 is not required. This option greatly reduces the
500 memory footprint of RCU.
501
Mike Travisc903ff82009-01-15 12:28:29 -0800502endchoice
503
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700504config PREEMPT_RCU
Paul E. McKenney127781d2013-03-27 08:44:00 -0700505 def_bool TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700506 help
507 This option enables preemptible-RCU code that is common between
Paul E. McKenneyab74fdf2014-05-04 15:41:21 -0700508 TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700509
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700510config RCU_STALL_COMMON
511 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
512 help
513 This option enables RCU CPU stall code that is common between
514 the TINY and TREE variants of RCU. The purpose is to allow
515 the tiny variants to disable RCU CPU stall warnings, while
516 making these warnings mandatory for the tree variants.
517
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100518config CONTEXT_TRACKING
519 bool
520
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200521config RCU_USER_QS
522 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100523 depends on HAVE_CONTEXT_TRACKING && SMP
524 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200525 help
526 This option sets hooks on kernel / userspace boundaries and
527 puts RCU in extended quiescent state when the CPU runs in
528 userspace. It means that when a CPU runs in userspace, it is
529 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700530 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200531
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200532 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100533 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700534 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200535
536 If unsure say N
537
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100538config CONTEXT_TRACKING_FORCE
539 bool "Force context tracking"
540 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200541 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200542 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200543 The major pre-requirement for full dynticks to work is to
544 support the context tracking subsystem. But there are also
545 other dependencies to provide in order to make the full
546 dynticks working.
547
548 This option stands for testing when an arch implements the
549 context tracking backend but doesn't yet fullfill all the
550 requirements to make the full dynticks feature working.
551 Without the full dynticks, there is no way to test the support
552 for context tracking and the subsystems that rely on it: RCU
553 userspace extended quiescent state and tickless cputime
554 accounting. This option copes with the absence of the full
555 dynticks subsystem by forcing the context tracking on all
556 CPUs in the system.
557
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400558 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200559 architecture backend for the context tracking.
560
561 Say N otherwise, this option brings an overhead that you
562 don't want in production.
563
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200564
Mike Travisc903ff82009-01-15 12:28:29 -0800565config RCU_FANOUT
566 int "Tree-based hierarchical RCU fanout value"
567 range 2 64 if 64BIT
568 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700569 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800570 default 64 if 64BIT
571 default 32 if !64BIT
572 help
573 This option controls the fanout of hierarchical implementations
574 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700575 large numbers of CPUs. This value must be at least the fourth
576 root of NR_CPUS, which allows NR_CPUS to be insanely large.
577 The default value of RCU_FANOUT should be used for production
578 systems, but if you are stress-testing the RCU implementation
579 itself, small RCU_FANOUT values allow you to test large-system
580 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800581
582 Select a specific number if testing RCU itself.
583 Take the default if unsure.
584
Paul E. McKenney8932a632012-04-19 12:20:14 -0700585config RCU_FANOUT_LEAF
586 int "Tree-based hierarchical RCU leaf-level fanout value"
587 range 2 RCU_FANOUT if 64BIT
588 range 2 RCU_FANOUT if !64BIT
589 depends on TREE_RCU || TREE_PREEMPT_RCU
590 default 16
591 help
592 This option controls the leaf-level fanout of hierarchical
593 implementations of RCU, and allows trading off cache misses
594 against lock contention. Systems that synchronize their
595 scheduling-clock interrupts for energy-efficiency reasons will
596 want the default because the smaller leaf-level fanout keeps
597 lock contention levels acceptably low. Very large systems
598 (hundreds or thousands of CPUs) will instead want to set this
599 value to the maximum value possible in order to reduce the
600 number of cache misses incurred during RCU's grace-period
601 initialization. These systems tend to run CPU-bound, and thus
602 are not helped by synchronized interrupts, and thus tend to
603 skew them, which reduces lock contention enough that large
604 leaf-level fanouts work well.
605
606 Select a specific number if testing RCU itself.
607
608 Select the maximum permissible value for large systems.
609
610 Take the default if unsure.
611
Mike Travisc903ff82009-01-15 12:28:29 -0800612config RCU_FANOUT_EXACT
613 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700614 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800615 default n
616 help
617 This option forces use of the exact RCU_FANOUT value specified,
618 regardless of imbalances in the hierarchy. This is useful for
619 testing RCU itself, and might one day be useful on systems with
620 strong NUMA behavior.
621
622 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
623
624 Say N if unsure.
625
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800626config RCU_FAST_NO_HZ
627 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Frederic Weisbecker3451d022011-08-10 23:21:01 +0200628 depends on NO_HZ_COMMON && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800629 default n
630 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800631 This option permits CPUs to enter dynticks-idle state even if
632 they have RCU callbacks queued, and prevents RCU from waking
633 these CPUs up more than roughly once every four jiffies (by
634 default, you can adjust this using the rcutree.rcu_idle_gp_delay
635 parameter), thus improving energy efficiency. On the other
636 hand, this option increases the duration of RCU grace periods,
637 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800638
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800639 Say Y if energy efficiency is critically important, and you
640 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800641
642 Say N if you are unsure.
643
Mike Travisc903ff82009-01-15 12:28:29 -0800644config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700645 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800646 select DEBUG_FS
647 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700648 This option provides tracing for the TREE_RCU and
649 TREE_PREEMPT_RCU implementations, permitting Makefile to
650 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800651
Paul E. McKenney24278d12010-09-27 17:25:23 -0700652config RCU_BOOST
653 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800654 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700655 default n
656 help
657 This option boosts the priority of preempted RCU readers that
658 block the current preemptible RCU grace period for too long.
659 This option also prevents heavy loads from blocking RCU
660 callback invocation for all flavors of RCU.
661
662 Say Y here if you are working with real-time apps or heavy loads
663 Say N here if you are unsure.
664
665config RCU_BOOST_PRIO
666 int "Real-time priority to boost RCU readers to"
667 range 1 99
668 depends on RCU_BOOST
669 default 1
670 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700671 This option specifies the real-time priority to which long-term
672 preempted RCU readers are to be boosted. If you are working
673 with a real-time application that has one or more CPU-bound
674 threads running at a real-time priority level, you should set
675 RCU_BOOST_PRIO to a priority higher then the highest-priority
676 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
677 of 1 is appropriate in the common case, which is real-time
678 applications that do not have any CPU-bound threads.
679
680 Some real-time applications might not have a single real-time
681 thread that saturates a given CPU, but instead might have
682 multiple real-time threads that, taken together, fully utilize
683 that CPU. In this case, you should set RCU_BOOST_PRIO to
684 a priority higher than the lowest-priority thread that is
685 conspiring to prevent the CPU from running any non-real-time
686 tasks. For example, if one thread at priority 10 and another
687 thread at priority 5 are between themselves fully consuming
688 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
689 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700690
691 Specify the real-time priority, or take the default if unsure.
692
693config RCU_BOOST_DELAY
694 int "Milliseconds to delay boosting after RCU grace-period start"
695 range 0 3000
696 depends on RCU_BOOST
697 default 500
698 help
699 This option specifies the time to wait after the beginning of
700 a given grace period before priority-boosting preempted RCU
701 readers blocking that grace period. Note that any RCU reader
702 blocking an expedited RCU grace period is boosted immediately.
703
704 Accept the default if unsure.
705
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700706config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700707 bool "Offload RCU callback processing from boot-selected CPUs"
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700708 depends on TREE_RCU || TREE_PREEMPT_RCU
709 default n
710 help
711 Use this option to reduce OS jitter for aggressive HPC or
712 real-time workloads. It can also be used to offload RCU
713 callback invocation to energy-efficient CPUs in battery-powered
714 asymmetric multiprocessors.
715
716 This option offloads callback invocation from the set of
717 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800718 For each such CPU, a kthread ("rcuox/N") will be created to
719 invoke callbacks, where the "N" is the CPU being offloaded,
720 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
721 "s" for RCU-sched. Nothing prevents this kthread from running
722 on the specified CPUs, but (1) the kthreads may be preempted
723 between each callback, and (2) affinity or cgroups can be used
724 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700725
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800726 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700727 Say N here if you are unsure.
728
Paul E. McKenney911af502013-02-11 10:23:27 -0800729choice
730 prompt "Build-forced no-CBs CPUs"
731 default RCU_NOCB_CPU_NONE
732 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700733 This option allows no-CBs CPUs (whose RCU callbacks are invoked
734 from kthreads rather than from softirq context) to be specified
735 at build time. Additional no-CBs CPUs may be specified by
736 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800737
738config RCU_NOCB_CPU_NONE
739 bool "No build_forced no-CBs CPUs"
Paul E. McKenneyb58cc462014-07-02 10:13:24 -0700740 depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
Paul E. McKenney911af502013-02-11 10:23:27 -0800741 help
742 This option does not force any of the CPUs to be no-CBs CPUs.
743 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700744 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
745 kthreads whose names begin with "rcuo". All other CPUs will
746 invoke their own RCU callbacks in softirq context.
747
748 Select this option if you want to choose no-CBs CPUs at
749 boot time, for example, to allow testing of different no-CBs
750 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800751
752config RCU_NOCB_CPU_ZERO
753 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenneyb58cc462014-07-02 10:13:24 -0700754 depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
Paul E. McKenney911af502013-02-11 10:23:27 -0800755 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700756 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
757 callbacks are invoked by a per-CPU kthread whose name begins
758 with "rcuo". Additional CPUs may be designated as no-CBs
759 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
760 All other CPUs will invoke their own RCU callbacks in softirq
761 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800762
763 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700764 or energy-efficiency reasons, but the real reason it exists
765 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800766
767config RCU_NOCB_CPU_ALL
768 bool "All CPUs are build_forced no-CBs CPUs"
769 depends on RCU_NOCB_CPU
770 help
771 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700772 boot parameter will be ignored. All CPUs' RCU callbacks will
773 be executed in the context of per-CPU rcuo kthreads created for
774 this purpose. Assuming that the kthreads whose names start with
775 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
776 on the remaining CPUs, but might decrease memory locality during
777 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800778
779 Select this if all CPUs need to be no-CBs CPUs for real-time
780 or energy-efficiency reasons.
781
782endchoice
783
Mike Travisc903ff82009-01-15 12:28:29 -0800784endmenu # "RCU Subsystem"
785
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700787 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 ---help---
789 This option enables the complete Linux kernel ".config" file
790 contents to be saved in the kernel. It provides documentation
791 of which kernel options are used in a running kernel or in an
792 on-disk kernel. This information can be extracted from the kernel
793 image file with the script scripts/extract-ikconfig and used as
794 input to rebuild the current kernel or to build another kernel.
795 It can also be extracted from a running kernel by reading
796 /proc/config.gz if enabled (below).
797
798config IKCONFIG_PROC
799 bool "Enable access to .config through /proc/config.gz"
800 depends on IKCONFIG && PROC_FS
801 ---help---
802 This option enables access to the kernel configuration file
803 through /proc/config.gz.
804
Alistair John Strachan794543a2007-05-08 00:31:15 -0700805config LOG_BUF_SHIFT
806 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
807 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700808 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700809 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700810 Select the minimal kernel log buffer size as a power of 2.
811 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
812 parameter, see below. Any higher size also might be forced
813 by "log_buf_len" boot parameter.
814
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700815 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700816 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700817 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700818 15 => 32 KB
819 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700820 13 => 8 KB
821 12 => 4 KB
822
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700823config LOG_CPU_MAX_BUF_SHIFT
824 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
825 range 0 21
826 default 12 if !BASE_SMALL
827 default 0 if BASE_SMALL
828 help
829 This option allows to increase the default ring buffer size
830 according to the number of CPUs. The value defines the contribution
831 of each CPU as a power of 2. The used space is typically only few
832 lines however it might be much more when problems are reported,
833 e.g. backtraces.
834
835 The increased size means that a new buffer has to be allocated and
836 the original static one is unused. It makes sense only on systems
837 with more CPUs. Therefore this value is used only when the sum of
838 contributions is greater than the half of the default kernel ring
839 buffer as defined by LOG_BUF_SHIFT. The default values are set
840 so that more than 64 CPUs are needed to trigger the allocation.
841
842 Also this option is ignored when "log_buf_len" kernel parameter is
843 used as it forces an exact (power of two) size of the ring buffer.
844
845 The number of possible CPUs is used for this computation ignoring
846 hotplugging making the compuation optimal for the the worst case
847 scenerio while allowing a simple algorithm to be used from bootup.
848
849 Examples shift values and their meaning:
850 17 => 128 KB for each CPU
851 16 => 64 KB for each CPU
852 15 => 32 KB for each CPU
853 14 => 16 KB for each CPU
854 13 => 8 KB for each CPU
855 12 => 4 KB for each CPU
856
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800857#
858# Architectures with an unreliable sched_clock() should select this:
859#
860config HAVE_UNSTABLE_SCHED_CLOCK
861 bool
862
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700863config GENERIC_SCHED_CLOCK
864 bool
865
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200866#
867# For architectures that want to enable the support for NUMA-affine scheduler
868# balancing logic:
869#
870config ARCH_SUPPORTS_NUMA_BALANCING
871 bool
872
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100873#
874# For architectures that know their GCC __int128 support is sound
875#
876config ARCH_SUPPORTS_INT128
877 bool
878
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200879# For architectures that (ab)use NUMA to represent different memory regions
880# all cpu-local but of different latencies, such as SuperH.
881#
882config ARCH_WANT_NUMA_VARIABLE_LOCALITY
883 bool
884
885#
886# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
887config ARCH_WANTS_PROT_NUMA_PROT_NONE
888 bool
889
890config ARCH_USES_NUMA_PROT_NONE
891 bool
892 default y
893 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
894 depends on NUMA_BALANCING
895
Mel Gorman1a687c22012-11-22 11:16:36 +0000896config NUMA_BALANCING_DEFAULT_ENABLED
897 bool "Automatically enable NUMA aware memory/task placement"
898 default y
899 depends on NUMA_BALANCING
900 help
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400901 If set, automatic NUMA balancing will be enabled if running on a NUMA
Mel Gorman1a687c22012-11-22 11:16:36 +0000902 machine.
903
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904config NUMA_BALANCING
905 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200906 depends on ARCH_SUPPORTS_NUMA_BALANCING
907 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
908 depends on SMP && NUMA && MIGRATION
909 help
910 This option adds support for automatic NUMA aware memory/task placement.
911 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400912 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200913
914 This system will be inactive on UMA systems.
915
Li Zefan23964d22009-01-15 13:50:58 -0800916menuconfig CGROUPS
917 boolean "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500918 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700919 help
Li Zefan23964d22009-01-15 13:50:58 -0800920 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800921 use with process control subsystems such as Cpusets, CFS, memory
922 controls or device isolation.
923 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800924 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800925 - Documentation/cgroups/ (features for grouping, isolation
926 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700927
928 Say N if unsure.
929
Li Zefan23964d22009-01-15 13:50:58 -0800930if CGROUPS
931
Paul Menage006cb992007-10-18 23:39:43 -0700932config CGROUP_DEBUG
933 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700934 default n
Paul Menage006cb992007-10-18 23:39:43 -0700935 help
936 This option enables a simple cgroup subsystem that
937 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800938 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700939
Li Zefan23964d22009-01-15 13:50:58 -0800940 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700941
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700942config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800943 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800944 help
945 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700946 cgroup.
947
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700948config CGROUP_DEVICE
949 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700950 help
951 Provides a cgroup implementing whitelists for devices which
952 a process in the cgroup can mknod or open.
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954config CPUSETS
955 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700957 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 allow dynamically partitioning a system into sets of CPUs and
959 Memory Nodes and assigning tasks to run only within those sets.
960 This is primarily useful on large SMP or NUMA systems.
961
962 Say N if unsure.
963
Li Zefan23964d22009-01-15 13:50:58 -0800964config PROC_PID_CPUSET
965 bool "Include legacy /proc/<pid>/cpuset file"
966 depends on CPUSETS
967 default y
968
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100969config CGROUP_CPUACCT
970 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100971 help
972 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800973 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100974
Pavel Emelianove552b662008-02-07 00:13:49 -0800975config RESOURCE_COUNTERS
976 bool "Resource counters"
977 help
978 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800979 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800980
Andrew Mortonc255a452012-07-31 16:43:02 -0700981config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800982 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700983 depends on RESOURCE_COUNTERS
Tejun Heo79bd9812013-11-22 18:20:42 -0500984 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800985 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700986 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100987 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800988
989 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700990 associated with each page of memory in the system. By this,
Sergey Dyaslyf60e2a92013-07-03 15:03:30 -0700991 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700992 usage tracking struct at boot. Total amount of this is printed out
993 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800994
995 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700996 sure you need the memory resource controller. Even when you enable
997 this, you can set "cgroup_disable=memory" at your boot option to
998 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800999 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -08001000
Andrew Mortonc255a452012-07-31 16:43:02 -07001001config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001002 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001003 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001004 help
1005 Add swap management feature to memory resource controller. When you
1006 enable this, you can limit mem+swap usage per cgroup. In other words,
1007 when you disable this, memory resource controller has no cares to
1008 usage of swap...a process can exhaust all of the swap. This extension
1009 is useful when you want to avoid exhaustion swap but this itself
1010 adds more overheads and consumes memory for remembering information.
1011 Especially if you use 32bit system or small memory system, please
1012 be careful about enabling this. When memory resource controller
1013 is disabled by boot option, this will be automatically disabled and
1014 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001015 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001016 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1017 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001018config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001019 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001020 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001021 default y
1022 help
1023 Memory Resource Controller Swap Extension comes with its price in
1024 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001025 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001026 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001027 parameter should have this option unselected.
1028 For those who want to have the feature enabled by default should
1029 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001030 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001031config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001032 bool "Memory Resource Controller Kernel Memory accounting"
1033 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001034 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001035 help
1036 The Kernel Memory extension for Memory Resource Controller can limit
1037 the amount of memory used by kernel objects in the system. Those are
1038 fundamentally different from the entities handled by the standard
1039 Memory Controller, which are page-based, and can be swapped. Users of
1040 the kmem extension can use it to guarantee that no group of processes
1041 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001042
Vladimir Davydov2ee06462014-06-04 16:07:28 -07001043 WARNING: Current implementation lacks reclaim support. That means
1044 allocation attempts will fail when close to the limit even if there
1045 are plenty of kmem available for reclaim. That makes this option
1046 unusable in real life so DO NOT SELECT IT unless for development
1047 purposes.
1048
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001049config CGROUP_HUGETLB
1050 bool "HugeTLB Resource Controller for Control Groups"
Kees Cook19c92392012-10-02 11:19:29 -07001051 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001052 default n
1053 help
1054 Provides a cgroup Resource Controller for HugeTLB pages.
1055 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1056 The limit is enforced during page fault. Since HugeTLB doesn't
1057 support page reclaim, enforcing the limit at page fault time implies
1058 that, the application will get SIGBUS signal if it tries to access
1059 HugeTLB pages beyond its limit. This requires the application to know
1060 beforehand how much HugeTLB pages it would require for its use. The
1061 control group is tracked in the third page lru pointer. This means
1062 that we cannot use the controller with huge page less than 3 pages.
1063
Stephane Eraniane5d13672011-02-14 11:20:01 +02001064config CGROUP_PERF
1065 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1066 depends on PERF_EVENTS && CGROUPS
1067 help
1068 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001069 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001070 designated cpu.
1071
1072 Say N if unsure.
1073
Dhaval Giani7c941432010-01-20 13:26:18 +01001074menuconfig CGROUP_SCHED
1075 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001076 default n
1077 help
1078 This feature lets CPU scheduler recognize task groups and control CPU
1079 bandwidth allocation to such task groups. It uses cgroups to group
1080 tasks.
1081
1082if CGROUP_SCHED
1083config FAIR_GROUP_SCHED
1084 bool "Group scheduling for SCHED_OTHER"
1085 depends on CGROUP_SCHED
1086 default CGROUP_SCHED
1087
Paul Turnerab84d312011-07-21 09:43:28 -07001088config CFS_BANDWIDTH
1089 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001090 depends on FAIR_GROUP_SCHED
1091 default n
1092 help
1093 This option allows users to define CPU bandwidth rates (limits) for
1094 tasks running within the fair group scheduler. Groups with no limit
1095 set are considered to be unconstrained and will run with no
1096 restriction.
1097 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1098
Dhaval Giani7c941432010-01-20 13:26:18 +01001099config RT_GROUP_SCHED
1100 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001101 depends on CGROUP_SCHED
1102 default n
1103 help
1104 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001105 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001106 schedule realtime tasks for non-root users until you allocate
1107 realtime bandwidth for them.
1108 See Documentation/scheduler/sched-rt-group.txt for more information.
1109
1110endif #CGROUP_SCHED
1111
Vivek Goyalafc24d42010-04-26 19:27:56 +02001112config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001113 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001114 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001115 default n
1116 ---help---
1117 Generic block IO controller cgroup interface. This is the common
1118 cgroup interface which should be used by various IO controlling
1119 policies.
1120
1121 Currently, CFQ IO scheduler uses it to recognize task groups and
1122 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001123 to such task groups. It is also used by bio throttling logic in
1124 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001125
1126 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001127 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001128 enabling proportional weight division of disk bandwidth in CFQ, set
1129 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001130 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001131
1132 See Documentation/cgroups/blkio-controller.txt for more information.
1133
1134config DEBUG_BLK_CGROUP
1135 bool "Enable Block IO controller debugging"
1136 depends on BLK_CGROUP
1137 default n
1138 ---help---
1139 Enable some debugging help. Currently it exports additional stat
1140 files in a cgroup which can be useful for debugging.
1141
Li Zefan23964d22009-01-15 13:50:58 -08001142endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001143
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001144config CHECKPOINT_RESTORE
1145 bool "Checkpoint/restore support" if EXPERT
1146 default n
1147 help
1148 Enables additional kernel features in a sake of checkpoint/restore.
1149 In particular it adds auxiliary prctl codes to setup process text,
1150 data and heap segment sizes, and a few additional /proc filesystem
1151 entries.
1152
1153 If unsure, say N here.
1154
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001155menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001156 bool "Namespaces support" if EXPERT
1157 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001158 help
1159 Provides the way to make tasks work with different objects using
1160 the same id. For example same IPC id may refer to different objects
1161 or same user id or pid may refer to different tasks when used in
1162 different namespaces.
1163
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001164if NAMESPACES
1165
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001166config UTS_NS
1167 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001168 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001169 help
1170 In this namespace tasks see different info provided with the
1171 uname() system call
1172
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001173config IPC_NS
1174 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001175 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001176 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001177 help
1178 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001179 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001180
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001181config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001182 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001183 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001184 help
1185 This allows containers, i.e. vservers, to use user namespaces
1186 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001187
1188 When user namespaces are enabled in the kernel it is
1189 recommended that the MEMCG and MEMCG_KMEM options also be
1190 enabled and that user-space use the memory control groups to
1191 limit the amount of memory a memory unprivileged users can
1192 use.
1193
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001194 If unsure, say N.
1195
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001196config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001197 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001198 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001199 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001200 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001201 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001202 pid namespaces. This is a building block of containers.
1203
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001204config NET_NS
1205 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001206 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001207 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001208 help
1209 Allow user space to create what appear to be multiple instances
1210 of the network stack.
1211
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001212endif # NAMESPACES
1213
Mike Galbraith5091faa2010-11-30 14:18:03 +01001214config SCHED_AUTOGROUP
1215 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001216 select CGROUPS
1217 select CGROUP_SCHED
1218 select FAIR_GROUP_SCHED
1219 help
1220 This option optimizes the scheduler for common desktop workloads by
1221 automatically creating and populating task groups. This separation
1222 of workloads isolates aggressive CPU burners (like build jobs) from
1223 desktop applications. Task group autogeneration is currently based
1224 upon task session.
1225
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001226config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001227 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001228 depends on SYSFS
1229 default n
1230 help
1231 This option adds code that switches the layout of the "block" class
1232 devices, to not show up in /sys/class/block/, but only in
1233 /sys/block/.
1234
1235 This switch is only active when the sysfs.deprecated=1 boot option is
1236 passed or the SYSFS_DEPRECATED_V2 option is set.
1237
1238 This option allows new kernels to run on old distributions and tools,
1239 which might get confused by /sys/class/block/. Since 2007/2008 all
1240 major distributions and tools handle this just fine.
1241
1242 Recent distributions and userspace tools after 2009/2010 depend on
1243 the existence of /sys/class/block/, and will not work with this
1244 option enabled.
1245
1246 Only if you are using a new kernel on an old distribution, you might
1247 need to say Y here.
1248
1249config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001250 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001251 default n
1252 depends on SYSFS
1253 depends on SYSFS_DEPRECATED
1254 help
1255 Enable deprecated sysfs by default.
1256
1257 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1258 option.
1259
1260 Only if you are using a new kernel on an old distribution, you might
1261 need to say Y here. Even then, odds are you would not need it
1262 enabled, you can always pass the boot option if absolutely necessary.
1263
1264config RELAY
1265 bool "Kernel->user space relay support (formerly relayfs)"
1266 help
1267 This option enables support for relay interface support in
1268 certain file systems (such as debugfs).
1269 It is designed to provide an efficient mechanism for tools and
1270 facilities to relay large amounts of data from kernel space to
1271 user space.
1272
1273 If unsure, say N.
1274
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001275config BLK_DEV_INITRD
1276 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1277 depends on BROKEN || !FRV
1278 help
1279 The initial RAM filesystem is a ramfs which is loaded by the
1280 boot loader (loadlin or lilo) and that is mounted as root
1281 before the normal boot procedure. It is typically used to
1282 load modules needed to mount the "real" root file system,
1283 etc. See <file:Documentation/initrd.txt> for details.
1284
1285 If RAM disk support (BLK_DEV_RAM) is also included, this
1286 also enables initial RAM disk (initrd) support and adds
1287 15 Kbytes (more on some other architectures) to the kernel size.
1288
1289 If unsure say Y.
1290
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001291if BLK_DEV_INITRD
1292
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001293source "usr/Kconfig"
1294
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001295endif
1296
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001297config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001298 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001299 help
1300 Enabling this option will pass "-Os" instead of "-O2" to gcc
1301 resulting in a smaller kernel.
1302
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001303 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001304
Randy Dunlap08470622006-09-30 23:28:13 -07001305config SYSCTL
1306 bool
1307
Randy Dunlapb943c462009-03-10 12:55:46 -07001308config ANON_INODES
1309 bool
1310
Mike Frysinger657a5202013-04-30 15:28:45 -07001311config HAVE_UID16
1312 bool
1313
1314config SYSCTL_EXCEPTION_TRACE
1315 bool
1316 help
1317 Enable support for /proc/sys/debug/exception-trace.
1318
1319config SYSCTL_ARCH_UNALIGN_NO_WARN
1320 bool
1321 help
1322 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1323 Allows arch to define/use @no_unaligned_warning to possibly warn
1324 about unaligned access emulation going on under the hood.
1325
1326config SYSCTL_ARCH_UNALIGN_ALLOW
1327 bool
1328 help
1329 Enable support for /proc/sys/kernel/unaligned-trap
1330 Allows arches to define/use @unaligned_enabled to runtime toggle
1331 the unaligned access emulation.
1332 see arch/parisc/kernel/unaligned.c for reference
1333
Mike Frysinger657a5202013-04-30 15:28:45 -07001334config HAVE_PCSPKR_PLATFORM
1335 bool
1336
David Rientjes6a108a12011-01-20 14:44:16 -08001337menuconfig EXPERT
1338 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001339 # Unhide debug options, to make the on-by-default options visible
1340 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 help
1342 This option allows certain base kernel options and settings
1343 to be disabled or tweaked. This is for specialized
1344 environments which can tolerate a "non-standard" kernel.
1345 Only use this if you really know what you are doing.
1346
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001347config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001348 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001349 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001350 default y
1351 help
1352 This enables the legacy 16-bit UID syscall wrappers.
1353
Fabian Frederickf6187762014-06-04 16:11:12 -07001354config SGETMASK_SYSCALL
1355 bool "sgetmask/ssetmask syscalls support" if EXPERT
1356 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1357 ---help---
1358 sys_sgetmask and sys_ssetmask are obsolete system calls
1359 no longer supported in libc but still enabled by default in some
1360 architectures.
1361
1362 If unsure, leave the default option here.
1363
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001364config SYSFS_SYSCALL
1365 bool "Sysfs syscall support" if EXPERT
1366 default y
1367 ---help---
1368 sys_sysfs is an obsolete system call no longer supported in libc.
1369 Note that disabling this option is more secure but might break
1370 compatibility with some systems.
1371
1372 If unsure say Y here.
1373
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001374config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001375 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001376 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001377 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001378 select SYSCTL
1379 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001380 sys_sysctl uses binary paths that have been found challenging
1381 to properly maintain and use. The interface in /proc/sys
1382 using paths with ascii names is now the primary path to this
1383 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001384
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001385 Almost nothing using the binary sysctl interface so if you are
1386 trying to save some space it is probably safe to disable this,
1387 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001388
WANG Congc736de62011-11-02 13:39:25 -07001389 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001390
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001392 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 default y
1394 help
1395 Say Y here to let the kernel print out symbolic crash information and
1396 symbolic stack backtraces. This increases the size of the kernel
1397 somewhat, as all symbols have to be loaded into the kernel image.
1398
1399config KALLSYMS_ALL
1400 bool "Include all symbols in kallsyms"
1401 depends on DEBUG_KERNEL && KALLSYMS
1402 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001403 Normally kallsyms only contains the symbols of functions for nicer
1404 OOPS messages and backtraces (i.e., symbols from the text and inittext
1405 sections). This is sufficient for most cases. And only in very rare
1406 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1407 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001409 This option makes sure that all symbols are loaded into the kernel
1410 image (i.e., symbols from all sections) in cost of increased kernel
1411 size (depending on the kernel configuration, it may be 300KiB or
1412 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001414 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001415
1416config PRINTK
1417 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001418 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001419 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001420 help
1421 This option enables normal printk support. Removing it
1422 eliminates most of the message strings from the kernel image
1423 and makes the kernel more or less silent. As this makes it
1424 very difficult to diagnose system problems, saying N here is
1425 strongly discouraged.
1426
Matt Mackallc8538a72005-05-01 08:59:01 -07001427config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001428 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001429 default y
1430 help
1431 Disabling this option eliminates support for BUG and WARN, reducing
1432 the size of your kernel image and potentially quietly ignoring
1433 numerous fatal conditions. You should only consider disabling this
1434 option for embedded systems with no facilities for reporting errors.
1435 Just say Y.
1436
Matt Mackall708e9a72006-01-08 01:05:25 -08001437config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001438 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001439 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001440 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001441 help
1442 Enable support for generating core dumps. Disabling saves about 4k.
1443
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001444
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001445config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001446 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001447 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001448 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001449 default y
1450 help
1451 This option allows to disable the internal PC-Speaker
1452 support, saving some memory.
1453
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454config BASE_FULL
1455 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001456 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 help
1458 Disabling this option reduces the size of miscellaneous core
1459 kernel data structures. This saves memory on small machines,
1460 but may reduce performance.
1461
1462config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001463 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001465 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 help
1467 Disabling this option will cause the kernel to be built without
1468 support for "fast userspace mutexes". The resulting kernel may not
1469 run glibc-based applications correctly.
1470
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001471config HAVE_FUTEX_CMPXCHG
1472 bool
1473 help
1474 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1475 is implemented and always working. This removes a couple of runtime
1476 checks.
1477
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001479 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001481 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 help
1483 Disabling this option will cause the kernel to be built without
1484 support for epoll family of system calls.
1485
Davide Libenzifba2afa2007-05-10 22:23:13 -07001486config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001487 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001488 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001489 default y
1490 help
1491 Enable the signalfd() system call that allows to receive signals
1492 on a file descriptor.
1493
1494 If unsure, say Y.
1495
Davide Libenzib215e282007-05-10 22:23:16 -07001496config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001497 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001498 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001499 default y
1500 help
1501 Enable the timerfd() system call that allows to receive timer
1502 events on a file descriptor.
1503
1504 If unsure, say Y.
1505
Davide Libenzie1ad7462007-05-10 22:23:19 -07001506config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001507 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001508 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001509 default y
1510 help
1511 Enable the eventfd() system call that allows to receive both
1512 kernel notification (ie. KAIO) or userspace notifications.
1513
1514 If unsure, say Y.
1515
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001517 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 default y
1519 depends on MMU
1520 help
1521 The shmem is an internal filesystem used to manage shared memory.
1522 It is backed by swap and manages resource limits. It is also exported
1523 to userspace as tmpfs if TMPFS is enabled. Disabling this
1524 option replaces shmem and tmpfs with the much simpler ramfs code,
1525 which may be appropriate on small systems without swap.
1526
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001527config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001528 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001529 default y
1530 help
1531 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001532 by some high performance threaded applications. Disabling
1533 this option saves about 7k.
1534
1535config PCI_QUIRKS
1536 default y
1537 bool "Enable PCI quirk workarounds" if EXPERT
1538 depends on PCI
1539 help
1540 This enables workarounds for various PCI chipset
1541 bugs/quirks. Disable this only if your target machine is
1542 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001543
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001544config EMBEDDED
1545 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001546 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001547 select EXPERT
1548 help
1549 This option should be enabled if compiling the kernel for
1550 an embedded system so certain expert options are available
1551 for configuration.
1552
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001553config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001554 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001555 help
1556 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001557
Peter Zijlstra906010b2009-09-21 16:08:49 +02001558config PERF_USE_VMALLOC
1559 bool
1560 help
1561 See tools/perf/design.txt for details
1562
Ingo Molnar57c0c152009-09-21 12:20:38 +02001563menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001564
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001565config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001566 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001567 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001568 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001569 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001570 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001571 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001572 Enable kernel support for various performance events provided
1573 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001574
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001575 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001576 use of generic tracepoints.
1577
1578 Most modern CPUs support performance events via performance
1579 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001580 types of hw events: such as instructions executed, cachemisses
1581 suffered, or branches mis-predicted - without slowing down the
1582 kernel or applications. These registers can also trigger interrupts
1583 when a threshold number of events have passed - and can thus be
1584 used to profile the code that runs on that CPU.
1585
Ingo Molnar57c0c152009-09-21 12:20:38 +02001586 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001587 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001588 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001589 provides per task and per CPU counters, and it provides event
1590 capabilities on top of those.
1591
1592 Say Y if unsure.
1593
Peter Zijlstra906010b2009-09-21 16:08:49 +02001594config DEBUG_PERF_USE_VMALLOC
1595 default n
1596 bool "Debug: use vmalloc to back perf mmap() buffers"
1597 depends on PERF_EVENTS && DEBUG_KERNEL
1598 select PERF_USE_VMALLOC
1599 help
1600 Use vmalloc memory to back perf mmap() buffers.
1601
1602 Mostly useful for debugging the vmalloc code on platforms
1603 that don't require it.
1604
1605 Say N if unsure.
1606
Thomas Gleixner0793a612008-12-04 20:12:29 +01001607endmenu
1608
Christoph Lameterf8891e52006-06-30 01:55:45 -07001609config VM_EVENT_COUNTERS
1610 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001611 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001612 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001613 VM event counters are needed for event counts to be shown.
1614 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001615 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001616 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001617
Christoph Lameter41ecc552007-05-09 02:32:44 -07001618config SLUB_DEBUG
1619 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001620 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001621 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001622 help
1623 SLUB has extensive debug support features. Disabling these can
1624 result in significant savings in code size. This also disables
1625 SLUB sysfs support. /sys/slab will not exist and there will be
1626 no support for cache validation etc.
1627
Randy Dunlapb943c462009-03-10 12:55:46 -07001628config COMPAT_BRK
1629 bool "Disable heap randomization"
1630 default y
1631 help
1632 Randomizing heap placement makes heap exploits harder, but it
1633 also breaks ancient binaries (including anything libc5 based).
1634 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001635 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001636 /proc/sys/kernel/randomize_va_space to 2.
1637
1638 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1639
Christoph Lameter81819f02007-05-06 14:49:36 -07001640choice
1641 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001642 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001643 help
1644 This option allows to select a slab allocator.
1645
1646config SLAB
1647 bool "SLAB"
1648 help
1649 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001650 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001651 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001652
1653config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001654 bool "SLUB (Unqueued Allocator)"
1655 help
1656 SLUB is a slab allocator that minimizes cache line usage
1657 instead of managing queues of cached objects (SLAB approach).
1658 Per cpu caching is realized using slabs of objects instead
1659 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001660 and has enhanced diagnostics. SLUB is the default choice for
1661 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001662
1663config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001664 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001665 bool "SLOB (Simple Allocator)"
1666 help
Matt Mackall37291452008-02-04 22:29:38 -08001667 SLOB replaces the stock allocator with a drastically simpler
1668 allocator. SLOB is generally more space efficient but
1669 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001670
1671endchoice
1672
Joonsoo Kim345c9052013-06-19 14:05:52 +09001673config SLUB_CPU_PARTIAL
1674 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001675 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001676 bool "SLUB per cpu partial cache"
1677 help
1678 Per cpu partial caches accellerate objects allocation and freeing
1679 that is local to a processor at the price of more indeterminism
1680 in the latency of the free. On overflow these caches will be cleared
1681 which requires the taking of locks that may cause latency spikes.
1682 Typically one would choose no for a realtime system.
1683
Jie Zhangea637632009-12-14 18:00:02 -08001684config MMAP_ALLOW_UNINITIALIZED
1685 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001686 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001687 default n
1688 help
1689 Normally, and according to the Linux spec, anonymous memory obtained
1690 from mmap() has it's contents cleared before it is passed to
1691 userspace. Enabling this config option allows you to request that
1692 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1693 providing a huge performance boost. If this option is not enabled,
1694 then the flag will be ignored.
1695
1696 This is taken advantage of by uClibc's malloc(), and also by
1697 ELF-FDPIC binfmt's brk and stack allocator.
1698
1699 Because of the obvious security issues, this option should only be
1700 enabled on embedded devices where you control what is run in
1701 userspace. Since that isn't generally a problem on no-MMU systems,
1702 it is normally safe to say Y here.
1703
1704 See Documentation/nommu-mmap.txt for more information.
1705
Peter Foley82c04ff2014-04-18 15:07:11 -07001706config SYSTEM_TRUSTED_KEYRING
1707 bool "Provide system-wide ring of trusted keys"
1708 depends on KEYS
1709 help
1710 Provide a system keyring to which trusted keys can be added. Keys in
1711 the keyring are considered to be trusted. Keys may be added at will
1712 by the kernel from compiled-in data and from hardware key stores, but
1713 userspace may only add extra keys if those keys can be verified by
1714 keys already in the keyring.
1715
1716 Keys in this keyring are used by module signature checking.
1717
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001718config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001719 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001720 help
1721 Say Y here to enable the extended profiling support mechanisms used
1722 by profilers such as OProfile.
1723
Ingo Molnar5f87f112008-07-23 14:15:22 +02001724#
1725# Place an empty function call at each tracepoint site. Can be
1726# dynamically changed for a probe function.
1727#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001728config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001729 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001730
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001731source "arch/Kconfig"
1732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733endmenu # General setup
1734
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001735config HAVE_GENERIC_DMA_COHERENT
1736 bool
1737 default n
1738
Linus Torvalds158a9622008-01-02 13:04:48 -08001739config SLABINFO
1740 bool
1741 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001742 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001743 default y
1744
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001745config RT_MUTEXES
1746 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001747
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748config BASE_SMALL
1749 int
1750 default 0 if BASE_FULL
1751 default 1 if !BASE_FULL
1752
Jan Engelhardt66da5732007-07-15 23:39:29 -07001753menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001755 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 help
1757 Kernel modules are small pieces of compiled code which can
1758 be inserted in the running kernel, rather than being
1759 permanently built into the kernel. You use the "modprobe"
1760 tool to add (and sometimes remove) them. If you say Y here,
1761 many parts of the kernel can be built as modules (by
1762 answering M instead of Y where indicated): this is most
1763 useful for infrequently used options which are not required
1764 for booting. For more information, see the man pages for
1765 modprobe, lsmod, modinfo, insmod and rmmod.
1766
1767 If you say Y here, you will need to run "make
1768 modules_install" to put the modules under /lib/modules/
1769 where modprobe can find them (you may need to be root to do
1770 this).
1771
1772 If unsure, say Y.
1773
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001774if MODULES
1775
Linus Torvalds826e4502008-05-04 17:04:16 -07001776config MODULE_FORCE_LOAD
1777 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001778 default n
1779 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001780 Allow loading of modules without version information (ie. modprobe
1781 --force). Forced module loading sets the 'F' (forced) taint flag and
1782 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001783
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784config MODULE_UNLOAD
1785 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 help
1787 Without this option you will not be able to unload any
1788 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001789 anyway), which makes your kernel smaller, faster
1790 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791
1792config MODULE_FORCE_UNLOAD
1793 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001794 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 help
1796 This option allows you to force a module to unload, even if the
1797 kernel believes it is unsafe: the kernel will remove the module
1798 without waiting for anyone to stop using it (using the -f option to
1799 rmmod). This is mainly for kernel developers and desperate users.
1800 If unsure, say N.
1801
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001803 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804 help
1805 Usually, you have to use modules compiled with your kernel.
1806 Saying Y here makes it sometimes possible to use modules
1807 compiled for different kernels, by adding enough information
1808 to the modules to (hopefully) spot any changes which would
1809 make them incompatible with the kernel you are running. If
1810 unsure, say N.
1811
1812config MODULE_SRCVERSION_ALL
1813 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 help
1815 Modules which contain a MODULE_VERSION get an extra "srcversion"
1816 field inserted into their modinfo section, which contains a
1817 sum of the source files which made it. This helps maintainers
1818 see exactly which source was used to build a module (since
1819 others sometimes change the module source without updating
1820 the version). With this option, such a "srcversion" field
1821 will be created for all modules. If unsure, say N.
1822
Rusty Russell106a4ee2012-09-26 10:09:40 +01001823config MODULE_SIG
1824 bool "Module signature verification"
1825 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001826 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001827 select KEYS
1828 select CRYPTO
1829 select ASYMMETRIC_KEY_TYPE
1830 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1831 select PUBLIC_KEY_ALGO_RSA
1832 select ASN1
1833 select OID_REGISTRY
1834 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001835 help
1836 Check modules for valid signatures upon load: the signature
1837 is simply appended to the module. For more information see
1838 Documentation/module-signing.txt.
1839
David Howellsea0b6dc2012-09-26 10:09:50 +01001840 !!!WARNING!!! If you enable this option, you MUST make sure that the
1841 module DOES NOT get stripped after being signed. This includes the
1842 debuginfo strip done by some packagers (such as rpmbuild) and
1843 inclusion into an initramfs that wants the module size reduced.
1844
Rusty Russell106a4ee2012-09-26 10:09:40 +01001845config MODULE_SIG_FORCE
1846 bool "Require modules to be validly signed"
1847 depends on MODULE_SIG
1848 help
1849 Reject unsigned modules or signed modules for which we don't have a
1850 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001851
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301852config MODULE_SIG_ALL
1853 bool "Automatically sign all modules"
1854 default y
1855 depends on MODULE_SIG
1856 help
1857 Sign all modules during make modules_install. Without this option,
1858 modules must be signed manually, using the scripts/sign-file tool.
1859
1860comment "Do not forget to sign required modules with scripts/sign-file"
1861 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1862
David Howellsea0b6dc2012-09-26 10:09:50 +01001863choice
1864 prompt "Which hash algorithm should modules be signed with?"
1865 depends on MODULE_SIG
1866 help
1867 This determines which sort of hashing algorithm will be used during
1868 signature generation. This algorithm _must_ be built into the kernel
1869 directly so that signature verification can take place. It is not
1870 possible to load a signed module containing the algorithm to check
1871 the signature on that module.
1872
1873config MODULE_SIG_SHA1
1874 bool "Sign modules with SHA-1"
1875 select CRYPTO_SHA1
1876
1877config MODULE_SIG_SHA224
1878 bool "Sign modules with SHA-224"
1879 select CRYPTO_SHA256
1880
1881config MODULE_SIG_SHA256
1882 bool "Sign modules with SHA-256"
1883 select CRYPTO_SHA256
1884
1885config MODULE_SIG_SHA384
1886 bool "Sign modules with SHA-384"
1887 select CRYPTO_SHA512
1888
1889config MODULE_SIG_SHA512
1890 bool "Sign modules with SHA-512"
1891 select CRYPTO_SHA512
1892
1893endchoice
1894
Michal Marek22753672013-01-25 13:41:00 +10301895config MODULE_SIG_HASH
1896 string
1897 depends on MODULE_SIG
1898 default "sha1" if MODULE_SIG_SHA1
1899 default "sha224" if MODULE_SIG_SHA224
1900 default "sha256" if MODULE_SIG_SHA256
1901 default "sha384" if MODULE_SIG_SHA384
1902 default "sha512" if MODULE_SIG_SHA512
1903
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001904endif # MODULES
1905
Rusty Russell98a79d62008-12-13 21:19:41 +10301906config INIT_ALL_POSSIBLE
1907 bool
1908 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301909 Back when each arch used to define their own cpu_online_mask and
1910 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301911 with all 1s, and others with all 0s. When they were centralised,
1912 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001913 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301914
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915config STOP_MACHINE
1916 bool
1917 default y
1918 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1919 help
1920 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001921
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001922source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001923
1924config PREEMPT_NOTIFIERS
1925 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001926
Steffen Klassert16295be2010-01-06 19:47:10 +11001927config PADATA
1928 depends on SMP
1929 bool
1930
Andi Kleen754b7b62012-10-04 17:11:27 -07001931# Can be selected by architectures with broken toolchains
1932# that get confused by correct const<->read_only section
1933# mappings
1934config BROKEN_RODATA
1935 bool
1936
David Howells4520c6a2012-09-21 23:31:13 +01001937config ASN1
1938 tristate
1939 help
1940 Build a simple ASN.1 grammar compiler that produces a bytecode output
1941 that can be interpreted by the ASN.1 stream decoder and used to
1942 inform it as to what tags are to be expected in a stream and what
1943 functions to call on what tags.
1944
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001945source "kernel/Kconfig.locks"