blob: dc24dec6023292ac6f1bd484ce506074d3e53566 [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
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700271 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700272 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"
Iulia Manda28138932015-04-15 16:16:41 -0700397 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200398 help
399 If you say Y here, a user level program will be able to instruct the
400 kernel (via a special system call) to write process accounting
401 information to a file: whenever a process exits, information about
402 that process will be appended to the file by the kernel. The
403 information includes things such as creation time, owning user,
404 command name, memory usage, controlling terminal etc. (the complete
405 list is in the struct acct in <file:include/linux/acct.h>). It is
406 up to the user level program to do useful things with this
407 information. This is generally a good idea, so say Y.
408
409config BSD_PROCESS_ACCT_V3
410 bool "BSD Process Accounting version 3 file format"
411 depends on BSD_PROCESS_ACCT
412 default n
413 help
414 If you say Y here, the process accounting information is written
415 in a new file format that also logs the process IDs of each
416 process and it's parent. Note that this file format is incompatible
417 with previous v0/v1/v2 file formats, so you will need updated tools
418 for processing it. A preliminary version of these tools is available
419 at <http://www.gnu.org/software/acct/>.
420
421config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700422 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200423 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700424 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200425 default n
426 help
427 Export selected statistics for tasks/processes through the
428 generic netlink interface. Unlike BSD process accounting, the
429 statistics are available during the lifetime of tasks/processes as
430 responses to commands. Like BSD accounting, they are sent to user
431 space on task exit.
432
433 Say N if unsure.
434
435config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700436 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200437 depends on TASKSTATS
438 help
439 Collect information on time spent by a task waiting for system
440 resources like cpu, synchronous block I/O completion and swapping
441 in pages. Such statistics can help in setting a task's priorities
442 relative to other tasks for cpu, io, rss limits etc.
443
444 Say N if unsure.
445
446config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700447 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200448 depends on TASKSTATS
449 help
450 Collect extended task accounting data and send the data
451 to userland for processing over the taskstats interface.
452
453 Say N if unsure.
454
455config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700456 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200457 depends on TASK_XACCT
458 help
459 Collect information on the number of bytes of storage I/O which this
460 task has caused.
461
462 Say N if unsure.
463
464endmenu # "CPU/Task time and stats accounting"
465
Mike Travisc903ff82009-01-15 12:28:29 -0800466menu "RCU Subsystem"
467
468choice
469 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700470 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800471
Mike Travisc903ff82009-01-15 12:28:29 -0800472config TREE_RCU
473 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700474 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800475 help
476 This option selects the RCU implementation that is
477 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700478 thousands of CPUs. It also scales down nicely to
479 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800480
Pranith Kumar28f65692014-09-22 14:00:48 -0400481config PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700482 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800483 depends on PREEMPT
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
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500504config SRCU
505 bool
506 help
507 This option selects the sleepable version of RCU. This version
508 permits arbitrary sleeping or blocking within RCU read-side critical
509 sections.
510
Paul E. McKenney8315f422014-06-27 13:42:20 -0700511config TASKS_RCU
512 bool "Task_based RCU implementation using voluntary context switch"
513 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500514 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700515 help
516 This option enables a task-based RCU implementation that uses
517 only voluntary context switch (not preemption!), idle, and
518 user-mode execution as quiescent states.
519
520 If unsure, say N.
521
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700522config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400523 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700524 help
525 This option enables RCU CPU stall code that is common between
526 the TINY and TREE variants of RCU. The purpose is to allow
527 the tiny variants to disable RCU CPU stall warnings, while
528 making these warnings mandatory for the tree variants.
529
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100530config CONTEXT_TRACKING
531 bool
532
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200533config RCU_USER_QS
534 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100535 depends on HAVE_CONTEXT_TRACKING && SMP
536 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200537 help
538 This option sets hooks on kernel / userspace boundaries and
539 puts RCU in extended quiescent state when the CPU runs in
540 userspace. It means that when a CPU runs in userspace, it is
541 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700542 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200543
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200544 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100545 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700546 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200547
548 If unsure say N
549
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100550config CONTEXT_TRACKING_FORCE
551 bool "Force context tracking"
552 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200553 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200554 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200555 The major pre-requirement for full dynticks to work is to
556 support the context tracking subsystem. But there are also
557 other dependencies to provide in order to make the full
558 dynticks working.
559
560 This option stands for testing when an arch implements the
561 context tracking backend but doesn't yet fullfill all the
562 requirements to make the full dynticks feature working.
563 Without the full dynticks, there is no way to test the support
564 for context tracking and the subsystems that rely on it: RCU
565 userspace extended quiescent state and tickless cputime
566 accounting. This option copes with the absence of the full
567 dynticks subsystem by forcing the context tracking on all
568 CPUs in the system.
569
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400570 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200571 architecture backend for the context tracking.
572
573 Say N otherwise, this option brings an overhead that you
574 don't want in production.
575
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200576
Mike Travisc903ff82009-01-15 12:28:29 -0800577config RCU_FANOUT
578 int "Tree-based hierarchical RCU fanout value"
579 range 2 64 if 64BIT
580 range 2 32 if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400581 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800582 default 64 if 64BIT
583 default 32 if !64BIT
584 help
585 This option controls the fanout of hierarchical implementations
586 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700587 large numbers of CPUs. This value must be at least the fourth
588 root of NR_CPUS, which allows NR_CPUS to be insanely large.
589 The default value of RCU_FANOUT should be used for production
590 systems, but if you are stress-testing the RCU implementation
591 itself, small RCU_FANOUT values allow you to test large-system
592 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800593
594 Select a specific number if testing RCU itself.
595 Take the default if unsure.
596
Paul E. McKenney8932a632012-04-19 12:20:14 -0700597config RCU_FANOUT_LEAF
598 int "Tree-based hierarchical RCU leaf-level fanout value"
599 range 2 RCU_FANOUT if 64BIT
600 range 2 RCU_FANOUT if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400601 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney8932a632012-04-19 12:20:14 -0700602 default 16
603 help
604 This option controls the leaf-level fanout of hierarchical
605 implementations of RCU, and allows trading off cache misses
606 against lock contention. Systems that synchronize their
607 scheduling-clock interrupts for energy-efficiency reasons will
608 want the default because the smaller leaf-level fanout keeps
609 lock contention levels acceptably low. Very large systems
610 (hundreds or thousands of CPUs) will instead want to set this
611 value to the maximum value possible in order to reduce the
612 number of cache misses incurred during RCU's grace-period
613 initialization. These systems tend to run CPU-bound, and thus
614 are not helped by synchronized interrupts, and thus tend to
615 skew them, which reduces lock contention enough that large
616 leaf-level fanouts work well.
617
618 Select a specific number if testing RCU itself.
619
620 Select the maximum permissible value for large systems.
621
622 Take the default if unsure.
623
Mike Travisc903ff82009-01-15 12:28:29 -0800624config RCU_FANOUT_EXACT
625 bool "Disable tree-based hierarchical RCU auto-balancing"
Pranith Kumar28f65692014-09-22 14:00:48 -0400626 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800627 default n
628 help
629 This option forces use of the exact RCU_FANOUT value specified,
630 regardless of imbalances in the hierarchy. This is useful for
631 testing RCU itself, and might one day be useful on systems with
632 strong NUMA behavior.
633
634 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
635
636 Say N if unsure.
637
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800638config RCU_FAST_NO_HZ
639 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Frederic Weisbecker3451d022011-08-10 23:21:01 +0200640 depends on NO_HZ_COMMON && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800641 default n
642 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800643 This option permits CPUs to enter dynticks-idle state even if
644 they have RCU callbacks queued, and prevents RCU from waking
645 these CPUs up more than roughly once every four jiffies (by
646 default, you can adjust this using the rcutree.rcu_idle_gp_delay
647 parameter), thus improving energy efficiency. On the other
648 hand, this option increases the duration of RCU grace periods,
649 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800650
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800651 Say Y if energy efficiency is critically important, and you
652 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800653
654 Say N if you are unsure.
655
Mike Travisc903ff82009-01-15 12:28:29 -0800656config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400657 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800658 select DEBUG_FS
659 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700660 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400661 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700662 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800663
Paul E. McKenney24278d12010-09-27 17:25:23 -0700664config RCU_BOOST
665 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800666 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700667 default n
668 help
669 This option boosts the priority of preempted RCU readers that
670 block the current preemptible RCU grace period for too long.
671 This option also prevents heavy loads from blocking RCU
672 callback invocation for all flavors of RCU.
673
674 Say Y here if you are working with real-time apps or heavy loads
675 Say N here if you are unsure.
676
Clark Williams21871d72014-09-12 21:21:09 -0500677config RCU_KTHREAD_PRIO
678 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800679 range 1 99 if RCU_BOOST
680 range 0 99 if !RCU_BOOST
681 default 1 if RCU_BOOST
682 default 0 if !RCU_BOOST
Paul E. McKenney24278d12010-09-27 17:25:23 -0700683 help
Clark Williams21871d72014-09-12 21:21:09 -0500684 This option specifies the SCHED_FIFO priority value that will be
685 assigned to the rcuc/n and rcub/n threads and is also the value
686 used for RCU_BOOST (if enabled). If you are working with a
687 real-time application that has one or more CPU-bound threads
688 running at a real-time priority level, you should set
689 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
690 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
691 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700692 applications that do not have any CPU-bound threads.
693
694 Some real-time applications might not have a single real-time
695 thread that saturates a given CPU, but instead might have
696 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500697 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700698 a priority higher than the lowest-priority thread that is
699 conspiring to prevent the CPU from running any non-real-time
700 tasks. For example, if one thread at priority 10 and another
701 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500702 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700703 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700704
705 Specify the real-time priority, or take the default if unsure.
706
707config RCU_BOOST_DELAY
708 int "Milliseconds to delay boosting after RCU grace-period start"
709 range 0 3000
710 depends on RCU_BOOST
711 default 500
712 help
713 This option specifies the time to wait after the beginning of
714 a given grace period before priority-boosting preempted RCU
715 readers blocking that grace period. Note that any RCU reader
716 blocking an expedited RCU grace period is boosted immediately.
717
718 Accept the default if unsure.
719
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700720config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700721 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400722 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700723 default n
724 help
725 Use this option to reduce OS jitter for aggressive HPC or
726 real-time workloads. It can also be used to offload RCU
727 callback invocation to energy-efficient CPUs in battery-powered
728 asymmetric multiprocessors.
729
730 This option offloads callback invocation from the set of
731 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800732 For each such CPU, a kthread ("rcuox/N") will be created to
733 invoke callbacks, where the "N" is the CPU being offloaded,
734 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
735 "s" for RCU-sched. Nothing prevents this kthread from running
736 on the specified CPUs, but (1) the kthreads may be preempted
737 between each callback, and (2) affinity or cgroups can be used
738 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700739
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800740 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700741 Say N here if you are unsure.
742
Paul E. McKenney911af502013-02-11 10:23:27 -0800743choice
744 prompt "Build-forced no-CBs CPUs"
745 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200746 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800747 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700748 This option allows no-CBs CPUs (whose RCU callbacks are invoked
749 from kthreads rather than from softirq context) to be specified
750 at build time. Additional no-CBs CPUs may be specified by
751 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800752
753config RCU_NOCB_CPU_NONE
754 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800755 help
756 This option does not force any of the CPUs to be no-CBs CPUs.
757 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700758 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
759 kthreads whose names begin with "rcuo". All other CPUs will
760 invoke their own RCU callbacks in softirq context.
761
762 Select this option if you want to choose no-CBs CPUs at
763 boot time, for example, to allow testing of different no-CBs
764 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800765
766config RCU_NOCB_CPU_ZERO
767 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800768 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700769 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
770 callbacks are invoked by a per-CPU kthread whose name begins
771 with "rcuo". Additional CPUs may be designated as no-CBs
772 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
773 All other CPUs will invoke their own RCU callbacks in softirq
774 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800775
776 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700777 or energy-efficiency reasons, but the real reason it exists
778 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800779
780config RCU_NOCB_CPU_ALL
781 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800782 help
783 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700784 boot parameter will be ignored. All CPUs' RCU callbacks will
785 be executed in the context of per-CPU rcuo kthreads created for
786 this purpose. Assuming that the kthreads whose names start with
787 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
788 on the remaining CPUs, but might decrease memory locality during
789 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800790
791 Select this if all CPUs need to be no-CBs CPUs for real-time
792 or energy-efficiency reasons.
793
794endchoice
795
Paul E. McKenneyee425712015-02-19 10:51:32 -0800796config RCU_EXPEDITE_BOOT
797 bool
798 default n
799 help
800 This option enables expedited grace periods at boot time,
801 as if rcu_expedite_gp() had been invoked early in boot.
802 The corresponding rcu_unexpedite_gp() is invoked from
803 rcu_end_inkernel_boot(), which is intended to be invoked
804 at the end of the kernel-only boot sequence, just before
805 init is exec'ed.
806
807 Accept the default if unsure.
808
Mike Travisc903ff82009-01-15 12:28:29 -0800809endmenu # "RCU Subsystem"
810
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700811config BUILD_BIN2C
812 bool
813 default n
814
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700816 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700817 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 ---help---
819 This option enables the complete Linux kernel ".config" file
820 contents to be saved in the kernel. It provides documentation
821 of which kernel options are used in a running kernel or in an
822 on-disk kernel. This information can be extracted from the kernel
823 image file with the script scripts/extract-ikconfig and used as
824 input to rebuild the current kernel or to build another kernel.
825 It can also be extracted from a running kernel by reading
826 /proc/config.gz if enabled (below).
827
828config IKCONFIG_PROC
829 bool "Enable access to .config through /proc/config.gz"
830 depends on IKCONFIG && PROC_FS
831 ---help---
832 This option enables access to the kernel configuration file
833 through /proc/config.gz.
834
Alistair John Strachan794543a2007-05-08 00:31:15 -0700835config LOG_BUF_SHIFT
836 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
837 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700838 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700839 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700840 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700841 Select the minimal kernel log buffer size as a power of 2.
842 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
843 parameter, see below. Any higher size also might be forced
844 by "log_buf_len" boot parameter.
845
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700846 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700847 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700848 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700849 15 => 32 KB
850 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700851 13 => 8 KB
852 12 => 4 KB
853
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700854config LOG_CPU_MAX_BUF_SHIFT
855 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700856 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700857 range 0 21
858 default 12 if !BASE_SMALL
859 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700860 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700861 help
862 This option allows to increase the default ring buffer size
863 according to the number of CPUs. The value defines the contribution
864 of each CPU as a power of 2. The used space is typically only few
865 lines however it might be much more when problems are reported,
866 e.g. backtraces.
867
868 The increased size means that a new buffer has to be allocated and
869 the original static one is unused. It makes sense only on systems
870 with more CPUs. Therefore this value is used only when the sum of
871 contributions is greater than the half of the default kernel ring
872 buffer as defined by LOG_BUF_SHIFT. The default values are set
873 so that more than 64 CPUs are needed to trigger the allocation.
874
875 Also this option is ignored when "log_buf_len" kernel parameter is
876 used as it forces an exact (power of two) size of the ring buffer.
877
878 The number of possible CPUs is used for this computation ignoring
879 hotplugging making the compuation optimal for the the worst case
880 scenerio while allowing a simple algorithm to be used from bootup.
881
882 Examples shift values and their meaning:
883 17 => 128 KB for each CPU
884 16 => 64 KB for each CPU
885 15 => 32 KB for each CPU
886 14 => 16 KB for each CPU
887 13 => 8 KB for each CPU
888 12 => 4 KB for each CPU
889
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800890#
891# Architectures with an unreliable sched_clock() should select this:
892#
893config HAVE_UNSTABLE_SCHED_CLOCK
894 bool
895
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700896config GENERIC_SCHED_CLOCK
897 bool
898
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200899#
900# For architectures that want to enable the support for NUMA-affine scheduler
901# balancing logic:
902#
903config ARCH_SUPPORTS_NUMA_BALANCING
904 bool
905
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100906#
907# For architectures that know their GCC __int128 support is sound
908#
909config ARCH_SUPPORTS_INT128
910 bool
911
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200912# For architectures that (ab)use NUMA to represent different memory regions
913# all cpu-local but of different latencies, such as SuperH.
914#
915config ARCH_WANT_NUMA_VARIABLE_LOCALITY
916 bool
917
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200918config NUMA_BALANCING
919 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200920 depends on ARCH_SUPPORTS_NUMA_BALANCING
921 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
922 depends on SMP && NUMA && MIGRATION
923 help
924 This option adds support for automatic NUMA aware memory/task placement.
925 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400926 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200927
928 This system will be inactive on UMA systems.
929
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800930config NUMA_BALANCING_DEFAULT_ENABLED
931 bool "Automatically enable NUMA aware memory/task placement"
932 default y
933 depends on NUMA_BALANCING
934 help
935 If set, automatic NUMA balancing will be enabled if running on a NUMA
936 machine.
937
Li Zefan23964d22009-01-15 13:50:58 -0800938menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500939 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500940 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700941 help
Li Zefan23964d22009-01-15 13:50:58 -0800942 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800943 use with process control subsystems such as Cpusets, CFS, memory
944 controls or device isolation.
945 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800946 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800947 - Documentation/cgroups/ (features for grouping, isolation
948 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700949
950 Say N if unsure.
951
Li Zefan23964d22009-01-15 13:50:58 -0800952if CGROUPS
953
Paul Menage006cb992007-10-18 23:39:43 -0700954config CGROUP_DEBUG
955 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700956 default n
Paul Menage006cb992007-10-18 23:39:43 -0700957 help
958 This option enables a simple cgroup subsystem that
959 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800960 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700961
Li Zefan23964d22009-01-15 13:50:58 -0800962 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700963
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700964config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800965 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800966 help
967 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700968 cgroup.
969
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700970config CGROUP_DEVICE
971 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700972 help
973 Provides a cgroup implementing whitelists for devices which
974 a process in the cgroup can mknod or open.
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976config CPUSETS
977 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700979 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 allow dynamically partitioning a system into sets of CPUs and
981 Memory Nodes and assigning tasks to run only within those sets.
982 This is primarily useful on large SMP or NUMA systems.
983
984 Say N if unsure.
985
Li Zefan23964d22009-01-15 13:50:58 -0800986config PROC_PID_CPUSET
987 bool "Include legacy /proc/<pid>/cpuset file"
988 depends on CPUSETS
989 default y
990
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100991config CGROUP_CPUACCT
992 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100993 help
994 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800995 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100996
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800997config PAGE_COUNTER
998 bool
999
Andrew Mortonc255a452012-07-31 16:43:02 -07001000config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -08001001 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -08001002 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -05001003 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -08001004 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -07001005 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +01001006 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -08001007
Andrew Mortonc255a452012-07-31 16:43:02 -07001008config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001009 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001010 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001011 help
1012 Add swap management feature to memory resource controller. When you
1013 enable this, you can limit mem+swap usage per cgroup. In other words,
1014 when you disable this, memory resource controller has no cares to
1015 usage of swap...a process can exhaust all of the swap. This extension
1016 is useful when you want to avoid exhaustion swap but this itself
1017 adds more overheads and consumes memory for remembering information.
1018 Especially if you use 32bit system or small memory system, please
1019 be careful about enabling this. When memory resource controller
1020 is disabled by boot option, this will be automatically disabled and
1021 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001022 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001023 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1024 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001025config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001026 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001027 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001028 default y
1029 help
1030 Memory Resource Controller Swap Extension comes with its price in
1031 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001032 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001033 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001034 parameter should have this option unselected.
1035 For those who want to have the feature enabled by default should
1036 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001037 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001038config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001039 bool "Memory Resource Controller Kernel Memory accounting"
1040 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001041 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001042 help
1043 The Kernel Memory extension for Memory Resource Controller can limit
1044 the amount of memory used by kernel objects in the system. Those are
1045 fundamentally different from the entities handled by the standard
1046 Memory Controller, which are page-based, and can be swapped. Users of
1047 the kmem extension can use it to guarantee that no group of processes
1048 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001049
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001050config CGROUP_HUGETLB
1051 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001052 depends on HUGETLB_PAGE
1053 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001054 default n
1055 help
1056 Provides a cgroup Resource Controller for HugeTLB pages.
1057 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1058 The limit is enforced during page fault. Since HugeTLB doesn't
1059 support page reclaim, enforcing the limit at page fault time implies
1060 that, the application will get SIGBUS signal if it tries to access
1061 HugeTLB pages beyond its limit. This requires the application to know
1062 beforehand how much HugeTLB pages it would require for its use. The
1063 control group is tracked in the third page lru pointer. This means
1064 that we cannot use the controller with huge page less than 3 pages.
1065
Stephane Eraniane5d13672011-02-14 11:20:01 +02001066config CGROUP_PERF
1067 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1068 depends on PERF_EVENTS && CGROUPS
1069 help
1070 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001071 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001072 designated cpu.
1073
1074 Say N if unsure.
1075
Dhaval Giani7c941432010-01-20 13:26:18 +01001076menuconfig CGROUP_SCHED
1077 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001078 default n
1079 help
1080 This feature lets CPU scheduler recognize task groups and control CPU
1081 bandwidth allocation to such task groups. It uses cgroups to group
1082 tasks.
1083
1084if CGROUP_SCHED
1085config FAIR_GROUP_SCHED
1086 bool "Group scheduling for SCHED_OTHER"
1087 depends on CGROUP_SCHED
1088 default CGROUP_SCHED
1089
Paul Turnerab84d312011-07-21 09:43:28 -07001090config CFS_BANDWIDTH
1091 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001092 depends on FAIR_GROUP_SCHED
1093 default n
1094 help
1095 This option allows users to define CPU bandwidth rates (limits) for
1096 tasks running within the fair group scheduler. Groups with no limit
1097 set are considered to be unconstrained and will run with no
1098 restriction.
1099 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1100
Dhaval Giani7c941432010-01-20 13:26:18 +01001101config RT_GROUP_SCHED
1102 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001103 depends on CGROUP_SCHED
1104 default n
1105 help
1106 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001107 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001108 schedule realtime tasks for non-root users until you allocate
1109 realtime bandwidth for them.
1110 See Documentation/scheduler/sched-rt-group.txt for more information.
1111
1112endif #CGROUP_SCHED
1113
Vivek Goyalafc24d42010-04-26 19:27:56 +02001114config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001115 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001116 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001117 default n
1118 ---help---
1119 Generic block IO controller cgroup interface. This is the common
1120 cgroup interface which should be used by various IO controlling
1121 policies.
1122
1123 Currently, CFQ IO scheduler uses it to recognize task groups and
1124 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001125 to such task groups. It is also used by bio throttling logic in
1126 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001127
1128 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001129 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001130 enabling proportional weight division of disk bandwidth in CFQ, set
1131 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001132 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001133
1134 See Documentation/cgroups/blkio-controller.txt for more information.
1135
1136config DEBUG_BLK_CGROUP
1137 bool "Enable Block IO controller debugging"
1138 depends on BLK_CGROUP
1139 default n
1140 ---help---
1141 Enable some debugging help. Currently it exports additional stat
1142 files in a cgroup which can be useful for debugging.
1143
Li Zefan23964d22009-01-15 13:50:58 -08001144endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001145
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001146config CHECKPOINT_RESTORE
1147 bool "Checkpoint/restore support" if EXPERT
1148 default n
1149 help
1150 Enables additional kernel features in a sake of checkpoint/restore.
1151 In particular it adds auxiliary prctl codes to setup process text,
1152 data and heap segment sizes, and a few additional /proc filesystem
1153 entries.
1154
1155 If unsure, say N here.
1156
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001157menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001158 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001159 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001160 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001161 help
1162 Provides the way to make tasks work with different objects using
1163 the same id. For example same IPC id may refer to different objects
1164 or same user id or pid may refer to different tasks when used in
1165 different namespaces.
1166
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001167if NAMESPACES
1168
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001169config UTS_NS
1170 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001171 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001172 help
1173 In this namespace tasks see different info provided with the
1174 uname() system call
1175
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001176config IPC_NS
1177 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001178 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001179 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001180 help
1181 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001182 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001183
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001184config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001185 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001186 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001187 help
1188 This allows containers, i.e. vservers, to use user namespaces
1189 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001190
1191 When user namespaces are enabled in the kernel it is
1192 recommended that the MEMCG and MEMCG_KMEM options also be
1193 enabled and that user-space use the memory control groups to
1194 limit the amount of memory a memory unprivileged users can
1195 use.
1196
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001197 If unsure, say N.
1198
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001199config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001200 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001201 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001202 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001203 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001204 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001205 pid namespaces. This is a building block of containers.
1206
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001207config NET_NS
1208 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001209 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001210 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001211 help
1212 Allow user space to create what appear to be multiple instances
1213 of the network stack.
1214
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001215endif # NAMESPACES
1216
Mike Galbraith5091faa2010-11-30 14:18:03 +01001217config SCHED_AUTOGROUP
1218 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001219 select CGROUPS
1220 select CGROUP_SCHED
1221 select FAIR_GROUP_SCHED
1222 help
1223 This option optimizes the scheduler for common desktop workloads by
1224 automatically creating and populating task groups. This separation
1225 of workloads isolates aggressive CPU burners (like build jobs) from
1226 desktop applications. Task group autogeneration is currently based
1227 upon task session.
1228
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001229config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001230 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001231 depends on SYSFS
1232 default n
1233 help
1234 This option adds code that switches the layout of the "block" class
1235 devices, to not show up in /sys/class/block/, but only in
1236 /sys/block/.
1237
1238 This switch is only active when the sysfs.deprecated=1 boot option is
1239 passed or the SYSFS_DEPRECATED_V2 option is set.
1240
1241 This option allows new kernels to run on old distributions and tools,
1242 which might get confused by /sys/class/block/. Since 2007/2008 all
1243 major distributions and tools handle this just fine.
1244
1245 Recent distributions and userspace tools after 2009/2010 depend on
1246 the existence of /sys/class/block/, and will not work with this
1247 option enabled.
1248
1249 Only if you are using a new kernel on an old distribution, you might
1250 need to say Y here.
1251
1252config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001253 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001254 default n
1255 depends on SYSFS
1256 depends on SYSFS_DEPRECATED
1257 help
1258 Enable deprecated sysfs by default.
1259
1260 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1261 option.
1262
1263 Only if you are using a new kernel on an old distribution, you might
1264 need to say Y here. Even then, odds are you would not need it
1265 enabled, you can always pass the boot option if absolutely necessary.
1266
1267config RELAY
1268 bool "Kernel->user space relay support (formerly relayfs)"
1269 help
1270 This option enables support for relay interface support in
1271 certain file systems (such as debugfs).
1272 It is designed to provide an efficient mechanism for tools and
1273 facilities to relay large amounts of data from kernel space to
1274 user space.
1275
1276 If unsure, say N.
1277
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001278config BLK_DEV_INITRD
1279 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1280 depends on BROKEN || !FRV
1281 help
1282 The initial RAM filesystem is a ramfs which is loaded by the
1283 boot loader (loadlin or lilo) and that is mounted as root
1284 before the normal boot procedure. It is typically used to
1285 load modules needed to mount the "real" root file system,
1286 etc. See <file:Documentation/initrd.txt> for details.
1287
1288 If RAM disk support (BLK_DEV_RAM) is also included, this
1289 also enables initial RAM disk (initrd) support and adds
1290 15 Kbytes (more on some other architectures) to the kernel size.
1291
1292 If unsure say Y.
1293
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001294if BLK_DEV_INITRD
1295
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001296source "usr/Kconfig"
1297
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001298endif
1299
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001300config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001301 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001302 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001303 Enabling this option will pass "-Os" instead of "-O2" to
1304 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001305
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001306 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001307
Randy Dunlap08470622006-09-30 23:28:13 -07001308config SYSCTL
1309 bool
1310
Randy Dunlapb943c462009-03-10 12:55:46 -07001311config ANON_INODES
1312 bool
1313
Mike Frysinger657a5202013-04-30 15:28:45 -07001314config HAVE_UID16
1315 bool
1316
1317config SYSCTL_EXCEPTION_TRACE
1318 bool
1319 help
1320 Enable support for /proc/sys/debug/exception-trace.
1321
1322config SYSCTL_ARCH_UNALIGN_NO_WARN
1323 bool
1324 help
1325 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1326 Allows arch to define/use @no_unaligned_warning to possibly warn
1327 about unaligned access emulation going on under the hood.
1328
1329config SYSCTL_ARCH_UNALIGN_ALLOW
1330 bool
1331 help
1332 Enable support for /proc/sys/kernel/unaligned-trap
1333 Allows arches to define/use @unaligned_enabled to runtime toggle
1334 the unaligned access emulation.
1335 see arch/parisc/kernel/unaligned.c for reference
1336
Mike Frysinger657a5202013-04-30 15:28:45 -07001337config HAVE_PCSPKR_PLATFORM
1338 bool
1339
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001340# interpreter that classic socket filters depend on
1341config BPF
1342 bool
1343
David Rientjes6a108a12011-01-20 14:44:16 -08001344menuconfig EXPERT
1345 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001346 # Unhide debug options, to make the on-by-default options visible
1347 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 help
1349 This option allows certain base kernel options and settings
1350 to be disabled or tweaked. This is for specialized
1351 environments which can tolerate a "non-standard" kernel.
1352 Only use this if you really know what you are doing.
1353
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001354config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001355 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001356 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001357 default y
1358 help
1359 This enables the legacy 16-bit UID syscall wrappers.
1360
Iulia Manda28138932015-04-15 16:16:41 -07001361config MULTIUSER
1362 bool "Multiple users, groups and capabilities support" if EXPERT
1363 default y
1364 help
1365 This option enables support for non-root users, groups and
1366 capabilities.
1367
1368 If you say N here, all processes will run with UID 0, GID 0, and all
1369 possible capabilities. Saying N here also compiles out support for
1370 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1371 setgid, and capset.
1372
1373 If unsure, say Y here.
1374
Fabian Frederickf6187762014-06-04 16:11:12 -07001375config SGETMASK_SYSCALL
1376 bool "sgetmask/ssetmask syscalls support" if EXPERT
1377 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1378 ---help---
1379 sys_sgetmask and sys_ssetmask are obsolete system calls
1380 no longer supported in libc but still enabled by default in some
1381 architectures.
1382
1383 If unsure, leave the default option here.
1384
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001385config SYSFS_SYSCALL
1386 bool "Sysfs syscall support" if EXPERT
1387 default y
1388 ---help---
1389 sys_sysfs is an obsolete system call no longer supported in libc.
1390 Note that disabling this option is more secure but might break
1391 compatibility with some systems.
1392
1393 If unsure say Y here.
1394
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001395config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001396 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001397 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001398 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001399 select SYSCTL
1400 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001401 sys_sysctl uses binary paths that have been found challenging
1402 to properly maintain and use. The interface in /proc/sys
1403 using paths with ascii names is now the primary path to this
1404 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001405
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001406 Almost nothing using the binary sysctl interface so if you are
1407 trying to save some space it is probably safe to disable this,
1408 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001409
WANG Congc736de62011-11-02 13:39:25 -07001410 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001411
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001413 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 default y
1415 help
1416 Say Y here to let the kernel print out symbolic crash information and
1417 symbolic stack backtraces. This increases the size of the kernel
1418 somewhat, as all symbols have to be loaded into the kernel image.
1419
1420config KALLSYMS_ALL
1421 bool "Include all symbols in kallsyms"
1422 depends on DEBUG_KERNEL && KALLSYMS
1423 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001424 Normally kallsyms only contains the symbols of functions for nicer
1425 OOPS messages and backtraces (i.e., symbols from the text and inittext
1426 sections). This is sufficient for most cases. And only in very rare
1427 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1428 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001430 This option makes sure that all symbols are loaded into the kernel
1431 image (i.e., symbols from all sections) in cost of increased kernel
1432 size (depending on the kernel configuration, it may be 300KiB or
1433 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001435 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001436
1437config PRINTK
1438 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001439 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001440 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001441 help
1442 This option enables normal printk support. Removing it
1443 eliminates most of the message strings from the kernel image
1444 and makes the kernel more or less silent. As this makes it
1445 very difficult to diagnose system problems, saying N here is
1446 strongly discouraged.
1447
Matt Mackallc8538a72005-05-01 08:59:01 -07001448config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001449 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001450 default y
1451 help
1452 Disabling this option eliminates support for BUG and WARN, reducing
1453 the size of your kernel image and potentially quietly ignoring
1454 numerous fatal conditions. You should only consider disabling this
1455 option for embedded systems with no facilities for reporting errors.
1456 Just say Y.
1457
Matt Mackall708e9a72006-01-08 01:05:25 -08001458config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001459 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001460 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001461 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001462 help
1463 Enable support for generating core dumps. Disabling saves about 4k.
1464
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001465
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001466config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001467 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001468 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001469 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001470 default y
1471 help
1472 This option allows to disable the internal PC-Speaker
1473 support, saving some memory.
1474
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475config BASE_FULL
1476 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001477 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 help
1479 Disabling this option reduces the size of miscellaneous core
1480 kernel data structures. This saves memory on small machines,
1481 but may reduce performance.
1482
1483config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001484 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001486 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 help
1488 Disabling this option will cause the kernel to be built without
1489 support for "fast userspace mutexes". The resulting kernel may not
1490 run glibc-based applications correctly.
1491
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001492config HAVE_FUTEX_CMPXCHG
1493 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001494 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001495 help
1496 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1497 is implemented and always working. This removes a couple of runtime
1498 checks.
1499
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001501 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001503 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 help
1505 Disabling this option will cause the kernel to be built without
1506 support for epoll family of system calls.
1507
Davide Libenzifba2afa2007-05-10 22:23:13 -07001508config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001509 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001510 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001511 default y
1512 help
1513 Enable the signalfd() system call that allows to receive signals
1514 on a file descriptor.
1515
1516 If unsure, say Y.
1517
Davide Libenzib215e282007-05-10 22:23:16 -07001518config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001519 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001520 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001521 default y
1522 help
1523 Enable the timerfd() system call that allows to receive timer
1524 events on a file descriptor.
1525
1526 If unsure, say Y.
1527
Davide Libenzie1ad7462007-05-10 22:23:19 -07001528config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001529 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001530 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001531 default y
1532 help
1533 Enable the eventfd() system call that allows to receive both
1534 kernel notification (ie. KAIO) or userspace notifications.
1535
1536 If unsure, say Y.
1537
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001538# syscall, maps, verifier
1539config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001540 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001541 select ANON_INODES
1542 select BPF
1543 default n
1544 help
1545 Enable the bpf() system call that allows to manipulate eBPF
1546 programs and maps via file descriptors.
1547
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001549 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550 default y
1551 depends on MMU
1552 help
1553 The shmem is an internal filesystem used to manage shared memory.
1554 It is backed by swap and manages resource limits. It is also exported
1555 to userspace as tmpfs if TMPFS is enabled. Disabling this
1556 option replaces shmem and tmpfs with the much simpler ramfs code,
1557 which may be appropriate on small systems without swap.
1558
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001559config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001560 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001561 default y
1562 help
1563 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001564 by some high performance threaded applications. Disabling
1565 this option saves about 7k.
1566
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001567config ADVISE_SYSCALLS
1568 bool "Enable madvise/fadvise syscalls" if EXPERT
1569 default y
1570 help
1571 This option enables the madvise and fadvise syscalls, used by
1572 applications to advise the kernel about their future memory or file
1573 usage, improving performance. If building an embedded system where no
1574 applications use these syscalls, you can disable this option to save
1575 space.
1576
Mike Frysinger657a5202013-04-30 15:28:45 -07001577config PCI_QUIRKS
1578 default y
1579 bool "Enable PCI quirk workarounds" if EXPERT
1580 depends on PCI
1581 help
1582 This enables workarounds for various PCI chipset
1583 bugs/quirks. Disable this only if your target machine is
1584 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001585
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001586config EMBEDDED
1587 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001588 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001589 select EXPERT
1590 help
1591 This option should be enabled if compiling the kernel for
1592 an embedded system so certain expert options are available
1593 for configuration.
1594
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001595config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001596 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001597 help
1598 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001599
Peter Zijlstra906010b2009-09-21 16:08:49 +02001600config PERF_USE_VMALLOC
1601 bool
1602 help
1603 See tools/perf/design.txt for details
1604
Ingo Molnar57c0c152009-09-21 12:20:38 +02001605menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001606
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001607config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001608 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001609 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001610 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001611 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001612 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001613 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001614 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001615 Enable kernel support for various performance events provided
1616 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001617
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001618 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001619 use of generic tracepoints.
1620
1621 Most modern CPUs support performance events via performance
1622 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001623 types of hw events: such as instructions executed, cachemisses
1624 suffered, or branches mis-predicted - without slowing down the
1625 kernel or applications. These registers can also trigger interrupts
1626 when a threshold number of events have passed - and can thus be
1627 used to profile the code that runs on that CPU.
1628
Ingo Molnar57c0c152009-09-21 12:20:38 +02001629 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001630 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001631 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001632 provides per task and per CPU counters, and it provides event
1633 capabilities on top of those.
1634
1635 Say Y if unsure.
1636
Peter Zijlstra906010b2009-09-21 16:08:49 +02001637config DEBUG_PERF_USE_VMALLOC
1638 default n
1639 bool "Debug: use vmalloc to back perf mmap() buffers"
1640 depends on PERF_EVENTS && DEBUG_KERNEL
1641 select PERF_USE_VMALLOC
1642 help
1643 Use vmalloc memory to back perf mmap() buffers.
1644
1645 Mostly useful for debugging the vmalloc code on platforms
1646 that don't require it.
1647
1648 Say N if unsure.
1649
Thomas Gleixner0793a612008-12-04 20:12:29 +01001650endmenu
1651
Christoph Lameterf8891e52006-06-30 01:55:45 -07001652config VM_EVENT_COUNTERS
1653 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001654 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001655 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001656 VM event counters are needed for event counts to be shown.
1657 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001658 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001659 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001660
Christoph Lameter41ecc552007-05-09 02:32:44 -07001661config SLUB_DEBUG
1662 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001663 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001664 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001665 help
1666 SLUB has extensive debug support features. Disabling these can
1667 result in significant savings in code size. This also disables
1668 SLUB sysfs support. /sys/slab will not exist and there will be
1669 no support for cache validation etc.
1670
Randy Dunlapb943c462009-03-10 12:55:46 -07001671config COMPAT_BRK
1672 bool "Disable heap randomization"
1673 default y
1674 help
1675 Randomizing heap placement makes heap exploits harder, but it
1676 also breaks ancient binaries (including anything libc5 based).
1677 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001678 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001679 /proc/sys/kernel/randomize_va_space to 2.
1680
1681 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1682
Christoph Lameter81819f02007-05-06 14:49:36 -07001683choice
1684 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001685 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001686 help
1687 This option allows to select a slab allocator.
1688
1689config SLAB
1690 bool "SLAB"
1691 help
1692 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001693 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001694 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001695
1696config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001697 bool "SLUB (Unqueued Allocator)"
1698 help
1699 SLUB is a slab allocator that minimizes cache line usage
1700 instead of managing queues of cached objects (SLAB approach).
1701 Per cpu caching is realized using slabs of objects instead
1702 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001703 and has enhanced diagnostics. SLUB is the default choice for
1704 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001705
1706config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001707 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001708 bool "SLOB (Simple Allocator)"
1709 help
Matt Mackall37291452008-02-04 22:29:38 -08001710 SLOB replaces the stock allocator with a drastically simpler
1711 allocator. SLOB is generally more space efficient but
1712 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001713
1714endchoice
1715
Joonsoo Kim345c9052013-06-19 14:05:52 +09001716config SLUB_CPU_PARTIAL
1717 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001718 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001719 bool "SLUB per cpu partial cache"
1720 help
1721 Per cpu partial caches accellerate objects allocation and freeing
1722 that is local to a processor at the price of more indeterminism
1723 in the latency of the free. On overflow these caches will be cleared
1724 which requires the taking of locks that may cause latency spikes.
1725 Typically one would choose no for a realtime system.
1726
Jie Zhangea637632009-12-14 18:00:02 -08001727config MMAP_ALLOW_UNINITIALIZED
1728 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001729 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001730 default n
1731 help
1732 Normally, and according to the Linux spec, anonymous memory obtained
1733 from mmap() has it's contents cleared before it is passed to
1734 userspace. Enabling this config option allows you to request that
1735 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1736 providing a huge performance boost. If this option is not enabled,
1737 then the flag will be ignored.
1738
1739 This is taken advantage of by uClibc's malloc(), and also by
1740 ELF-FDPIC binfmt's brk and stack allocator.
1741
1742 Because of the obvious security issues, this option should only be
1743 enabled on embedded devices where you control what is run in
1744 userspace. Since that isn't generally a problem on no-MMU systems,
1745 it is normally safe to say Y here.
1746
1747 See Documentation/nommu-mmap.txt for more information.
1748
Peter Foley82c04ff2014-04-18 15:07:11 -07001749config SYSTEM_TRUSTED_KEYRING
1750 bool "Provide system-wide ring of trusted keys"
1751 depends on KEYS
1752 help
1753 Provide a system keyring to which trusted keys can be added. Keys in
1754 the keyring are considered to be trusted. Keys may be added at will
1755 by the kernel from compiled-in data and from hardware key stores, but
1756 userspace may only add extra keys if those keys can be verified by
1757 keys already in the keyring.
1758
1759 Keys in this keyring are used by module signature checking.
1760
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001761config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001762 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001763 help
1764 Say Y here to enable the extended profiling support mechanisms used
1765 by profilers such as OProfile.
1766
Ingo Molnar5f87f112008-07-23 14:15:22 +02001767#
1768# Place an empty function call at each tracepoint site. Can be
1769# dynamically changed for a probe function.
1770#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001771config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001772 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001773
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001774source "arch/Kconfig"
1775
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776endmenu # General setup
1777
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001778config HAVE_GENERIC_DMA_COHERENT
1779 bool
1780 default n
1781
Linus Torvalds158a9622008-01-02 13:04:48 -08001782config SLABINFO
1783 bool
1784 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001785 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001786 default y
1787
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001788config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001789 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001790
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791config BASE_SMALL
1792 int
1793 default 0 if BASE_FULL
1794 default 1 if !BASE_FULL
1795
Jan Engelhardt66da5732007-07-15 23:39:29 -07001796menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001798 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 help
1800 Kernel modules are small pieces of compiled code which can
1801 be inserted in the running kernel, rather than being
1802 permanently built into the kernel. You use the "modprobe"
1803 tool to add (and sometimes remove) them. If you say Y here,
1804 many parts of the kernel can be built as modules (by
1805 answering M instead of Y where indicated): this is most
1806 useful for infrequently used options which are not required
1807 for booting. For more information, see the man pages for
1808 modprobe, lsmod, modinfo, insmod and rmmod.
1809
1810 If you say Y here, you will need to run "make
1811 modules_install" to put the modules under /lib/modules/
1812 where modprobe can find them (you may need to be root to do
1813 this).
1814
1815 If unsure, say Y.
1816
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001817if MODULES
1818
Linus Torvalds826e4502008-05-04 17:04:16 -07001819config MODULE_FORCE_LOAD
1820 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001821 default n
1822 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001823 Allow loading of modules without version information (ie. modprobe
1824 --force). Forced module loading sets the 'F' (forced) taint flag and
1825 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001826
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827config MODULE_UNLOAD
1828 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 help
1830 Without this option you will not be able to unload any
1831 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001832 anyway), which makes your kernel smaller, faster
1833 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834
1835config MODULE_FORCE_UNLOAD
1836 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001837 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 help
1839 This option allows you to force a module to unload, even if the
1840 kernel believes it is unsafe: the kernel will remove the module
1841 without waiting for anyone to stop using it (using the -f option to
1842 rmmod). This is mainly for kernel developers and desperate users.
1843 If unsure, say N.
1844
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001846 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847 help
1848 Usually, you have to use modules compiled with your kernel.
1849 Saying Y here makes it sometimes possible to use modules
1850 compiled for different kernels, by adding enough information
1851 to the modules to (hopefully) spot any changes which would
1852 make them incompatible with the kernel you are running. If
1853 unsure, say N.
1854
1855config MODULE_SRCVERSION_ALL
1856 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 help
1858 Modules which contain a MODULE_VERSION get an extra "srcversion"
1859 field inserted into their modinfo section, which contains a
1860 sum of the source files which made it. This helps maintainers
1861 see exactly which source was used to build a module (since
1862 others sometimes change the module source without updating
1863 the version). With this option, such a "srcversion" field
1864 will be created for all modules. If unsure, say N.
1865
Rusty Russell106a4ee2012-09-26 10:09:40 +01001866config MODULE_SIG
1867 bool "Module signature verification"
1868 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001869 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001870 select KEYS
1871 select CRYPTO
1872 select ASYMMETRIC_KEY_TYPE
1873 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1874 select PUBLIC_KEY_ALGO_RSA
1875 select ASN1
1876 select OID_REGISTRY
1877 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001878 help
1879 Check modules for valid signatures upon load: the signature
1880 is simply appended to the module. For more information see
1881 Documentation/module-signing.txt.
1882
David Howellsea0b6dc2012-09-26 10:09:50 +01001883 !!!WARNING!!! If you enable this option, you MUST make sure that the
1884 module DOES NOT get stripped after being signed. This includes the
1885 debuginfo strip done by some packagers (such as rpmbuild) and
1886 inclusion into an initramfs that wants the module size reduced.
1887
Rusty Russell106a4ee2012-09-26 10:09:40 +01001888config MODULE_SIG_FORCE
1889 bool "Require modules to be validly signed"
1890 depends on MODULE_SIG
1891 help
1892 Reject unsigned modules or signed modules for which we don't have a
1893 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001894
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301895config MODULE_SIG_ALL
1896 bool "Automatically sign all modules"
1897 default y
1898 depends on MODULE_SIG
1899 help
1900 Sign all modules during make modules_install. Without this option,
1901 modules must be signed manually, using the scripts/sign-file tool.
1902
1903comment "Do not forget to sign required modules with scripts/sign-file"
1904 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1905
David Howellsea0b6dc2012-09-26 10:09:50 +01001906choice
1907 prompt "Which hash algorithm should modules be signed with?"
1908 depends on MODULE_SIG
1909 help
1910 This determines which sort of hashing algorithm will be used during
1911 signature generation. This algorithm _must_ be built into the kernel
1912 directly so that signature verification can take place. It is not
1913 possible to load a signed module containing the algorithm to check
1914 the signature on that module.
1915
1916config MODULE_SIG_SHA1
1917 bool "Sign modules with SHA-1"
1918 select CRYPTO_SHA1
1919
1920config MODULE_SIG_SHA224
1921 bool "Sign modules with SHA-224"
1922 select CRYPTO_SHA256
1923
1924config MODULE_SIG_SHA256
1925 bool "Sign modules with SHA-256"
1926 select CRYPTO_SHA256
1927
1928config MODULE_SIG_SHA384
1929 bool "Sign modules with SHA-384"
1930 select CRYPTO_SHA512
1931
1932config MODULE_SIG_SHA512
1933 bool "Sign modules with SHA-512"
1934 select CRYPTO_SHA512
1935
1936endchoice
1937
Michal Marek22753672013-01-25 13:41:00 +10301938config MODULE_SIG_HASH
1939 string
1940 depends on MODULE_SIG
1941 default "sha1" if MODULE_SIG_SHA1
1942 default "sha224" if MODULE_SIG_SHA224
1943 default "sha256" if MODULE_SIG_SHA256
1944 default "sha384" if MODULE_SIG_SHA384
1945 default "sha512" if MODULE_SIG_SHA512
1946
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301947config MODULE_COMPRESS
1948 bool "Compress modules on installation"
1949 depends on MODULES
1950 help
1951 This option compresses the kernel modules when 'make
1952 modules_install' is run.
1953
1954 The modules will be compressed either using gzip or xz depend on the
1955 choice made in "Compression algorithm".
1956
1957 module-init-tools has support for gzip format while kmod handle gzip
1958 and xz compressed modules.
1959
1960 When a kernel module is installed from outside of the main kernel
1961 source and uses the Kbuild system for installing modules then that
1962 kernel module will also be compressed when it is installed.
1963
1964 This option provides little benefit when the modules are to be used inside
1965 an initrd or initramfs, it generally is more efficient to compress the whole
1966 initrd or initramfs instead.
1967
1968 This is fully compatible with signed modules while the signed module is
1969 compressed. module-init-tools or kmod handles decompression and provide to
1970 other layer the uncompressed but signed payload.
1971
1972choice
1973 prompt "Compression algorithm"
1974 depends on MODULE_COMPRESS
1975 default MODULE_COMPRESS_GZIP
1976 help
1977 This determines which sort of compression will be used during
1978 'make modules_install'.
1979
1980 GZIP (default) and XZ are supported.
1981
1982config MODULE_COMPRESS_GZIP
1983 bool "GZIP"
1984
1985config MODULE_COMPRESS_XZ
1986 bool "XZ"
1987
1988endchoice
1989
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001990endif # MODULES
1991
Rusty Russell98a79d62008-12-13 21:19:41 +10301992config INIT_ALL_POSSIBLE
1993 bool
1994 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301995 Back when each arch used to define their own cpu_online_mask and
1996 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301997 with all 1s, and others with all 0s. When they were centralised,
1998 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001999 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10302000
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001config STOP_MACHINE
2002 bool
2003 default y
2004 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
2005 help
2006 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002007
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002008source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07002009
2010config PREEMPT_NOTIFIERS
2011 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01002012
Steffen Klassert16295be2010-01-06 19:47:10 +11002013config PADATA
2014 depends on SMP
2015 bool
2016
Andi Kleen754b7b62012-10-04 17:11:27 -07002017# Can be selected by architectures with broken toolchains
2018# that get confused by correct const<->read_only section
2019# mappings
2020config BROKEN_RODATA
2021 bool
2022
David Howells4520c6a2012-09-21 23:31:13 +01002023config ASN1
2024 tristate
2025 help
2026 Build a simple ASN.1 grammar compiler that produces a bytecode output
2027 that can be interpreted by the ASN.1 stream decoder and used to
2028 inform it as to what tags are to be expected in a stream and what
2029 functions to call on what tags.
2030
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002031source "kernel/Kconfig.locks"