blob: af2c93c4a105857d8998cf82b6d2a86c94508eda [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
Paul E. McKenney78cae102015-04-20 12:19:45 -0700504config RCU_EXPERT
505 bool "Make expert-level adjustments to RCU configuration"
506 default n
507 help
508 This option needs to be enabled if you wish to make
509 expert-level adjustments to RCU configuration. By default,
510 no such adjustments can be made, which has the often-beneficial
511 side-effect of preventing "make oldconfig" from asking you all
512 sorts of detailed questions about how you would like numerous
513 obscure RCU options to be set up.
514
515 Say Y if you need to make expert-level adjustments to RCU.
516
517 Say N if you are unsure.
518
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500519config SRCU
520 bool
521 help
522 This option selects the sleepable version of RCU. This version
523 permits arbitrary sleeping or blocking within RCU read-side critical
524 sections.
525
Paul E. McKenney8315f422014-06-27 13:42:20 -0700526config TASKS_RCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -0700527 bool
Paul E. McKenney8315f422014-06-27 13:42:20 -0700528 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500529 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700530 help
531 This option enables a task-based RCU implementation that uses
532 only voluntary context switch (not preemption!), idle, and
533 user-mode execution as quiescent states.
534
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700535config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400536 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700537 help
538 This option enables RCU CPU stall code that is common between
539 the TINY and TREE variants of RCU. The purpose is to allow
540 the tiny variants to disable RCU CPU stall warnings, while
541 making these warnings mandatory for the tree variants.
542
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100543config CONTEXT_TRACKING
544 bool
545
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200546config RCU_USER_QS
Paul E. McKenney7db21ed2015-04-20 06:17:15 -0700547 bool
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200548 help
549 This option sets hooks on kernel / userspace boundaries and
550 puts RCU in extended quiescent state when the CPU runs in
551 userspace. It means that when a CPU runs in userspace, it is
552 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700553 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200554
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100555config CONTEXT_TRACKING_FORCE
556 bool "Force context tracking"
557 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200558 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200559 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200560 The major pre-requirement for full dynticks to work is to
561 support the context tracking subsystem. But there are also
562 other dependencies to provide in order to make the full
563 dynticks working.
564
565 This option stands for testing when an arch implements the
566 context tracking backend but doesn't yet fullfill all the
567 requirements to make the full dynticks feature working.
568 Without the full dynticks, there is no way to test the support
569 for context tracking and the subsystems that rely on it: RCU
570 userspace extended quiescent state and tickless cputime
571 accounting. This option copes with the absence of the full
572 dynticks subsystem by forcing the context tracking on all
573 CPUs in the system.
574
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400575 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200576 architecture backend for the context tracking.
577
578 Say N otherwise, this option brings an overhead that you
579 don't want in production.
580
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200581
Mike Travisc903ff82009-01-15 12:28:29 -0800582config RCU_FANOUT
583 int "Tree-based hierarchical RCU fanout value"
584 range 2 64 if 64BIT
585 range 2 32 if !64BIT
Paul E. McKenney05c5df32015-04-20 14:27:43 -0700586 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Mike Travisc903ff82009-01-15 12:28:29 -0800587 default 64 if 64BIT
588 default 32 if !64BIT
589 help
590 This option controls the fanout of hierarchical implementations
591 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700592 large numbers of CPUs. This value must be at least the fourth
593 root of NR_CPUS, which allows NR_CPUS to be insanely large.
594 The default value of RCU_FANOUT should be used for production
595 systems, but if you are stress-testing the RCU implementation
596 itself, small RCU_FANOUT values allow you to test large-system
597 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800598
599 Select a specific number if testing RCU itself.
600 Take the default if unsure.
601
Paul E. McKenney8932a632012-04-19 12:20:14 -0700602config RCU_FANOUT_LEAF
603 int "Tree-based hierarchical RCU leaf-level fanout value"
Paul E. McKenney8739c5c2015-04-20 18:27:54 -0700604 range 2 64 if 64BIT
605 range 2 32 if !64BIT
Paul E. McKenney47d631a2015-04-21 09:12:13 -0700606 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Paul E. McKenney8932a632012-04-19 12:20:14 -0700607 default 16
608 help
609 This option controls the leaf-level fanout of hierarchical
610 implementations of RCU, and allows trading off cache misses
611 against lock contention. Systems that synchronize their
612 scheduling-clock interrupts for energy-efficiency reasons will
613 want the default because the smaller leaf-level fanout keeps
614 lock contention levels acceptably low. Very large systems
615 (hundreds or thousands of CPUs) will instead want to set this
616 value to the maximum value possible in order to reduce the
617 number of cache misses incurred during RCU's grace-period
618 initialization. These systems tend to run CPU-bound, and thus
619 are not helped by synchronized interrupts, and thus tend to
620 skew them, which reduces lock contention enough that large
621 leaf-level fanouts work well.
622
623 Select a specific number if testing RCU itself.
624
625 Select the maximum permissible value for large systems.
626
627 Take the default if unsure.
628
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800629config RCU_FAST_NO_HZ
630 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700631 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800632 default n
633 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800634 This option permits CPUs to enter dynticks-idle state even if
635 they have RCU callbacks queued, and prevents RCU from waking
636 these CPUs up more than roughly once every four jiffies (by
637 default, you can adjust this using the rcutree.rcu_idle_gp_delay
638 parameter), thus improving energy efficiency. On the other
639 hand, this option increases the duration of RCU grace periods,
640 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800641
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800642 Say Y if energy efficiency is critically important, and you
643 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800644
645 Say N if you are unsure.
646
Mike Travisc903ff82009-01-15 12:28:29 -0800647config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400648 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800649 select DEBUG_FS
650 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700651 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400652 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700653 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800654
Paul E. McKenney24278d12010-09-27 17:25:23 -0700655config RCU_BOOST
656 bool "Enable RCU priority boosting"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700657 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700658 default n
659 help
660 This option boosts the priority of preempted RCU readers that
661 block the current preemptible RCU grace period for too long.
662 This option also prevents heavy loads from blocking RCU
663 callback invocation for all flavors of RCU.
664
665 Say Y here if you are working with real-time apps or heavy loads
666 Say N here if you are unsure.
667
Clark Williams21871d72014-09-12 21:21:09 -0500668config RCU_KTHREAD_PRIO
669 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800670 range 1 99 if RCU_BOOST
671 range 0 99 if !RCU_BOOST
672 default 1 if RCU_BOOST
673 default 0 if !RCU_BOOST
Paul E. McKenney26730f52015-04-21 09:22:14 -0700674 depends on RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700675 help
Clark Williams21871d72014-09-12 21:21:09 -0500676 This option specifies the SCHED_FIFO priority value that will be
677 assigned to the rcuc/n and rcub/n threads and is also the value
678 used for RCU_BOOST (if enabled). If you are working with a
679 real-time application that has one or more CPU-bound threads
680 running at a real-time priority level, you should set
681 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
682 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
683 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700684 applications that do not have any CPU-bound threads.
685
686 Some real-time applications might not have a single real-time
687 thread that saturates a given CPU, but instead might have
688 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500689 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700690 a priority higher than the lowest-priority thread that is
691 conspiring to prevent the CPU from running any non-real-time
692 tasks. For example, if one thread at priority 10 and another
693 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500694 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700695 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700696
697 Specify the real-time priority, or take the default if unsure.
698
699config RCU_BOOST_DELAY
700 int "Milliseconds to delay boosting after RCU grace-period start"
701 range 0 3000
702 depends on RCU_BOOST
703 default 500
704 help
705 This option specifies the time to wait after the beginning of
706 a given grace period before priority-boosting preempted RCU
707 readers blocking that grace period. Note that any RCU reader
708 blocking an expedited RCU grace period is boosted immediately.
709
710 Accept the default if unsure.
711
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700712config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700713 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400714 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700715 default n
716 help
717 Use this option to reduce OS jitter for aggressive HPC or
718 real-time workloads. It can also be used to offload RCU
719 callback invocation to energy-efficient CPUs in battery-powered
720 asymmetric multiprocessors.
721
722 This option offloads callback invocation from the set of
723 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800724 For each such CPU, a kthread ("rcuox/N") will be created to
725 invoke callbacks, where the "N" is the CPU being offloaded,
726 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
727 "s" for RCU-sched. Nothing prevents this kthread from running
728 on the specified CPUs, but (1) the kthreads may be preempted
729 between each callback, and (2) affinity or cgroups can be used
730 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700731
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800732 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700733 Say N here if you are unsure.
734
Paul E. McKenney911af502013-02-11 10:23:27 -0800735choice
736 prompt "Build-forced no-CBs CPUs"
737 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200738 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800739 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700740 This option allows no-CBs CPUs (whose RCU callbacks are invoked
741 from kthreads rather than from softirq context) to be specified
742 at build time. Additional no-CBs CPUs may be specified by
743 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800744
745config RCU_NOCB_CPU_NONE
746 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800747 help
748 This option does not force any of the CPUs to be no-CBs CPUs.
749 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700750 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
751 kthreads whose names begin with "rcuo". All other CPUs will
752 invoke their own RCU callbacks in softirq context.
753
754 Select this option if you want to choose no-CBs CPUs at
755 boot time, for example, to allow testing of different no-CBs
756 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800757
758config RCU_NOCB_CPU_ZERO
759 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800760 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700761 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
762 callbacks are invoked by a per-CPU kthread whose name begins
763 with "rcuo". Additional CPUs may be designated as no-CBs
764 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
765 All other CPUs will invoke their own RCU callbacks in softirq
766 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800767
768 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700769 or energy-efficiency reasons, but the real reason it exists
770 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800771
772config RCU_NOCB_CPU_ALL
773 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800774 help
775 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700776 boot parameter will be ignored. All CPUs' RCU callbacks will
777 be executed in the context of per-CPU rcuo kthreads created for
778 this purpose. Assuming that the kthreads whose names start with
779 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
780 on the remaining CPUs, but might decrease memory locality during
781 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800782
783 Select this if all CPUs need to be no-CBs CPUs for real-time
784 or energy-efficiency reasons.
785
786endchoice
787
Paul E. McKenneyee425712015-02-19 10:51:32 -0800788config RCU_EXPEDITE_BOOT
789 bool
790 default n
791 help
792 This option enables expedited grace periods at boot time,
793 as if rcu_expedite_gp() had been invoked early in boot.
794 The corresponding rcu_unexpedite_gp() is invoked from
795 rcu_end_inkernel_boot(), which is intended to be invoked
796 at the end of the kernel-only boot sequence, just before
797 init is exec'ed.
798
799 Accept the default if unsure.
800
Mike Travisc903ff82009-01-15 12:28:29 -0800801endmenu # "RCU Subsystem"
802
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700803config BUILD_BIN2C
804 bool
805 default n
806
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700808 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700809 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 ---help---
811 This option enables the complete Linux kernel ".config" file
812 contents to be saved in the kernel. It provides documentation
813 of which kernel options are used in a running kernel or in an
814 on-disk kernel. This information can be extracted from the kernel
815 image file with the script scripts/extract-ikconfig and used as
816 input to rebuild the current kernel or to build another kernel.
817 It can also be extracted from a running kernel by reading
818 /proc/config.gz if enabled (below).
819
820config IKCONFIG_PROC
821 bool "Enable access to .config through /proc/config.gz"
822 depends on IKCONFIG && PROC_FS
823 ---help---
824 This option enables access to the kernel configuration file
825 through /proc/config.gz.
826
Alistair John Strachan794543a2007-05-08 00:31:15 -0700827config LOG_BUF_SHIFT
828 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
829 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700830 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700831 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700832 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700833 Select the minimal kernel log buffer size as a power of 2.
834 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
835 parameter, see below. Any higher size also might be forced
836 by "log_buf_len" boot parameter.
837
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700838 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700839 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700840 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700841 15 => 32 KB
842 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700843 13 => 8 KB
844 12 => 4 KB
845
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700846config LOG_CPU_MAX_BUF_SHIFT
847 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700848 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700849 range 0 21
850 default 12 if !BASE_SMALL
851 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700852 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700853 help
854 This option allows to increase the default ring buffer size
855 according to the number of CPUs. The value defines the contribution
856 of each CPU as a power of 2. The used space is typically only few
857 lines however it might be much more when problems are reported,
858 e.g. backtraces.
859
860 The increased size means that a new buffer has to be allocated and
861 the original static one is unused. It makes sense only on systems
862 with more CPUs. Therefore this value is used only when the sum of
863 contributions is greater than the half of the default kernel ring
864 buffer as defined by LOG_BUF_SHIFT. The default values are set
865 so that more than 64 CPUs are needed to trigger the allocation.
866
867 Also this option is ignored when "log_buf_len" kernel parameter is
868 used as it forces an exact (power of two) size of the ring buffer.
869
870 The number of possible CPUs is used for this computation ignoring
871 hotplugging making the compuation optimal for the the worst case
872 scenerio while allowing a simple algorithm to be used from bootup.
873
874 Examples shift values and their meaning:
875 17 => 128 KB for each CPU
876 16 => 64 KB for each CPU
877 15 => 32 KB for each CPU
878 14 => 16 KB for each CPU
879 13 => 8 KB for each CPU
880 12 => 4 KB for each CPU
881
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800882#
883# Architectures with an unreliable sched_clock() should select this:
884#
885config HAVE_UNSTABLE_SCHED_CLOCK
886 bool
887
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700888config GENERIC_SCHED_CLOCK
889 bool
890
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200891#
892# For architectures that want to enable the support for NUMA-affine scheduler
893# balancing logic:
894#
895config ARCH_SUPPORTS_NUMA_BALANCING
896 bool
897
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100898#
899# For architectures that know their GCC __int128 support is sound
900#
901config ARCH_SUPPORTS_INT128
902 bool
903
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904# For architectures that (ab)use NUMA to represent different memory regions
905# all cpu-local but of different latencies, such as SuperH.
906#
907config ARCH_WANT_NUMA_VARIABLE_LOCALITY
908 bool
909
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200910config NUMA_BALANCING
911 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200912 depends on ARCH_SUPPORTS_NUMA_BALANCING
913 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
914 depends on SMP && NUMA && MIGRATION
915 help
916 This option adds support for automatic NUMA aware memory/task placement.
917 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400918 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200919
920 This system will be inactive on UMA systems.
921
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800922config NUMA_BALANCING_DEFAULT_ENABLED
923 bool "Automatically enable NUMA aware memory/task placement"
924 default y
925 depends on NUMA_BALANCING
926 help
927 If set, automatic NUMA balancing will be enabled if running on a NUMA
928 machine.
929
Li Zefan23964d22009-01-15 13:50:58 -0800930menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500931 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500932 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700933 help
Li Zefan23964d22009-01-15 13:50:58 -0800934 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800935 use with process control subsystems such as Cpusets, CFS, memory
936 controls or device isolation.
937 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800938 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800939 - Documentation/cgroups/ (features for grouping, isolation
940 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700941
942 Say N if unsure.
943
Li Zefan23964d22009-01-15 13:50:58 -0800944if CGROUPS
945
Paul Menage006cb992007-10-18 23:39:43 -0700946config CGROUP_DEBUG
947 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700948 default n
Paul Menage006cb992007-10-18 23:39:43 -0700949 help
950 This option enables a simple cgroup subsystem that
951 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800952 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700953
Li Zefan23964d22009-01-15 13:50:58 -0800954 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700955
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700956config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800957 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800958 help
959 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700960 cgroup.
961
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700962config CGROUP_DEVICE
963 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700964 help
965 Provides a cgroup implementing whitelists for devices which
966 a process in the cgroup can mknod or open.
967
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968config CPUSETS
969 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700971 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 allow dynamically partitioning a system into sets of CPUs and
973 Memory Nodes and assigning tasks to run only within those sets.
974 This is primarily useful on large SMP or NUMA systems.
975
976 Say N if unsure.
977
Li Zefan23964d22009-01-15 13:50:58 -0800978config PROC_PID_CPUSET
979 bool "Include legacy /proc/<pid>/cpuset file"
980 depends on CPUSETS
981 default y
982
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100983config CGROUP_CPUACCT
984 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100985 help
986 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800987 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100988
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800989config PAGE_COUNTER
990 bool
991
Andrew Mortonc255a452012-07-31 16:43:02 -0700992config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800993 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800994 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500995 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800996 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700997 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100998 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800999
Andrew Mortonc255a452012-07-31 16:43:02 -07001000config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001001 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001002 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001003 help
1004 Add swap management feature to memory resource controller. When you
1005 enable this, you can limit mem+swap usage per cgroup. In other words,
1006 when you disable this, memory resource controller has no cares to
1007 usage of swap...a process can exhaust all of the swap. This extension
1008 is useful when you want to avoid exhaustion swap but this itself
1009 adds more overheads and consumes memory for remembering information.
1010 Especially if you use 32bit system or small memory system, please
1011 be careful about enabling this. When memory resource controller
1012 is disabled by boot option, this will be automatically disabled and
1013 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001014 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001015 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1016 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001017config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001018 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001019 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001020 default y
1021 help
1022 Memory Resource Controller Swap Extension comes with its price in
1023 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001024 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001025 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001026 parameter should have this option unselected.
1027 For those who want to have the feature enabled by default should
1028 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001029 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001030config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001031 bool "Memory Resource Controller Kernel Memory accounting"
1032 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001033 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001034 help
1035 The Kernel Memory extension for Memory Resource Controller can limit
1036 the amount of memory used by kernel objects in the system. Those are
1037 fundamentally different from the entities handled by the standard
1038 Memory Controller, which are page-based, and can be swapped. Users of
1039 the kmem extension can use it to guarantee that no group of processes
1040 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001041
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001042config CGROUP_HUGETLB
1043 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001044 depends on HUGETLB_PAGE
1045 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001046 default n
1047 help
1048 Provides a cgroup Resource Controller for HugeTLB pages.
1049 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1050 The limit is enforced during page fault. Since HugeTLB doesn't
1051 support page reclaim, enforcing the limit at page fault time implies
1052 that, the application will get SIGBUS signal if it tries to access
1053 HugeTLB pages beyond its limit. This requires the application to know
1054 beforehand how much HugeTLB pages it would require for its use. The
1055 control group is tracked in the third page lru pointer. This means
1056 that we cannot use the controller with huge page less than 3 pages.
1057
Stephane Eraniane5d13672011-02-14 11:20:01 +02001058config CGROUP_PERF
1059 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1060 depends on PERF_EVENTS && CGROUPS
1061 help
1062 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001063 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001064 designated cpu.
1065
1066 Say N if unsure.
1067
Dhaval Giani7c941432010-01-20 13:26:18 +01001068menuconfig CGROUP_SCHED
1069 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001070 default n
1071 help
1072 This feature lets CPU scheduler recognize task groups and control CPU
1073 bandwidth allocation to such task groups. It uses cgroups to group
1074 tasks.
1075
1076if CGROUP_SCHED
1077config FAIR_GROUP_SCHED
1078 bool "Group scheduling for SCHED_OTHER"
1079 depends on CGROUP_SCHED
1080 default CGROUP_SCHED
1081
Paul Turnerab84d312011-07-21 09:43:28 -07001082config CFS_BANDWIDTH
1083 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001084 depends on FAIR_GROUP_SCHED
1085 default n
1086 help
1087 This option allows users to define CPU bandwidth rates (limits) for
1088 tasks running within the fair group scheduler. Groups with no limit
1089 set are considered to be unconstrained and will run with no
1090 restriction.
1091 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1092
Dhaval Giani7c941432010-01-20 13:26:18 +01001093config RT_GROUP_SCHED
1094 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001095 depends on CGROUP_SCHED
1096 default n
1097 help
1098 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001099 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001100 schedule realtime tasks for non-root users until you allocate
1101 realtime bandwidth for them.
1102 See Documentation/scheduler/sched-rt-group.txt for more information.
1103
1104endif #CGROUP_SCHED
1105
Vivek Goyalafc24d42010-04-26 19:27:56 +02001106config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001107 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001108 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001109 default n
1110 ---help---
1111 Generic block IO controller cgroup interface. This is the common
1112 cgroup interface which should be used by various IO controlling
1113 policies.
1114
1115 Currently, CFQ IO scheduler uses it to recognize task groups and
1116 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001117 to such task groups. It is also used by bio throttling logic in
1118 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001119
1120 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001121 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001122 enabling proportional weight division of disk bandwidth in CFQ, set
1123 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001124 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001125
1126 See Documentation/cgroups/blkio-controller.txt for more information.
1127
1128config DEBUG_BLK_CGROUP
1129 bool "Enable Block IO controller debugging"
1130 depends on BLK_CGROUP
1131 default n
1132 ---help---
1133 Enable some debugging help. Currently it exports additional stat
1134 files in a cgroup which can be useful for debugging.
1135
Li Zefan23964d22009-01-15 13:50:58 -08001136endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001137
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001138config CHECKPOINT_RESTORE
1139 bool "Checkpoint/restore support" if EXPERT
1140 default n
1141 help
1142 Enables additional kernel features in a sake of checkpoint/restore.
1143 In particular it adds auxiliary prctl codes to setup process text,
1144 data and heap segment sizes, and a few additional /proc filesystem
1145 entries.
1146
1147 If unsure, say N here.
1148
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001149menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001150 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001151 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001152 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001153 help
1154 Provides the way to make tasks work with different objects using
1155 the same id. For example same IPC id may refer to different objects
1156 or same user id or pid may refer to different tasks when used in
1157 different namespaces.
1158
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001159if NAMESPACES
1160
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001161config UTS_NS
1162 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001163 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001164 help
1165 In this namespace tasks see different info provided with the
1166 uname() system call
1167
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001168config IPC_NS
1169 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001170 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001171 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001172 help
1173 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001174 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001175
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001176config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001177 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001178 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001179 help
1180 This allows containers, i.e. vservers, to use user namespaces
1181 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001182
1183 When user namespaces are enabled in the kernel it is
1184 recommended that the MEMCG and MEMCG_KMEM options also be
1185 enabled and that user-space use the memory control groups to
1186 limit the amount of memory a memory unprivileged users can
1187 use.
1188
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001189 If unsure, say N.
1190
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001191config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001192 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001193 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001194 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001195 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001196 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001197 pid namespaces. This is a building block of containers.
1198
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001199config NET_NS
1200 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001201 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001202 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001203 help
1204 Allow user space to create what appear to be multiple instances
1205 of the network stack.
1206
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001207endif # NAMESPACES
1208
Mike Galbraith5091faa2010-11-30 14:18:03 +01001209config SCHED_AUTOGROUP
1210 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001211 select CGROUPS
1212 select CGROUP_SCHED
1213 select FAIR_GROUP_SCHED
1214 help
1215 This option optimizes the scheduler for common desktop workloads by
1216 automatically creating and populating task groups. This separation
1217 of workloads isolates aggressive CPU burners (like build jobs) from
1218 desktop applications. Task group autogeneration is currently based
1219 upon task session.
1220
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001221config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001222 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001223 depends on SYSFS
1224 default n
1225 help
1226 This option adds code that switches the layout of the "block" class
1227 devices, to not show up in /sys/class/block/, but only in
1228 /sys/block/.
1229
1230 This switch is only active when the sysfs.deprecated=1 boot option is
1231 passed or the SYSFS_DEPRECATED_V2 option is set.
1232
1233 This option allows new kernels to run on old distributions and tools,
1234 which might get confused by /sys/class/block/. Since 2007/2008 all
1235 major distributions and tools handle this just fine.
1236
1237 Recent distributions and userspace tools after 2009/2010 depend on
1238 the existence of /sys/class/block/, and will not work with this
1239 option enabled.
1240
1241 Only if you are using a new kernel on an old distribution, you might
1242 need to say Y here.
1243
1244config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001245 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001246 default n
1247 depends on SYSFS
1248 depends on SYSFS_DEPRECATED
1249 help
1250 Enable deprecated sysfs by default.
1251
1252 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1253 option.
1254
1255 Only if you are using a new kernel on an old distribution, you might
1256 need to say Y here. Even then, odds are you would not need it
1257 enabled, you can always pass the boot option if absolutely necessary.
1258
1259config RELAY
1260 bool "Kernel->user space relay support (formerly relayfs)"
1261 help
1262 This option enables support for relay interface support in
1263 certain file systems (such as debugfs).
1264 It is designed to provide an efficient mechanism for tools and
1265 facilities to relay large amounts of data from kernel space to
1266 user space.
1267
1268 If unsure, say N.
1269
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001270config BLK_DEV_INITRD
1271 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1272 depends on BROKEN || !FRV
1273 help
1274 The initial RAM filesystem is a ramfs which is loaded by the
1275 boot loader (loadlin or lilo) and that is mounted as root
1276 before the normal boot procedure. It is typically used to
1277 load modules needed to mount the "real" root file system,
1278 etc. See <file:Documentation/initrd.txt> for details.
1279
1280 If RAM disk support (BLK_DEV_RAM) is also included, this
1281 also enables initial RAM disk (initrd) support and adds
1282 15 Kbytes (more on some other architectures) to the kernel size.
1283
1284 If unsure say Y.
1285
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001286if BLK_DEV_INITRD
1287
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001288source "usr/Kconfig"
1289
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001290endif
1291
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001292config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001293 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001294 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001295 Enabling this option will pass "-Os" instead of "-O2" to
1296 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001297
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001298 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001299
Randy Dunlap08470622006-09-30 23:28:13 -07001300config SYSCTL
1301 bool
1302
Randy Dunlapb943c462009-03-10 12:55:46 -07001303config ANON_INODES
1304 bool
1305
Mike Frysinger657a5202013-04-30 15:28:45 -07001306config HAVE_UID16
1307 bool
1308
1309config SYSCTL_EXCEPTION_TRACE
1310 bool
1311 help
1312 Enable support for /proc/sys/debug/exception-trace.
1313
1314config SYSCTL_ARCH_UNALIGN_NO_WARN
1315 bool
1316 help
1317 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1318 Allows arch to define/use @no_unaligned_warning to possibly warn
1319 about unaligned access emulation going on under the hood.
1320
1321config SYSCTL_ARCH_UNALIGN_ALLOW
1322 bool
1323 help
1324 Enable support for /proc/sys/kernel/unaligned-trap
1325 Allows arches to define/use @unaligned_enabled to runtime toggle
1326 the unaligned access emulation.
1327 see arch/parisc/kernel/unaligned.c for reference
1328
Mike Frysinger657a5202013-04-30 15:28:45 -07001329config HAVE_PCSPKR_PLATFORM
1330 bool
1331
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001332# interpreter that classic socket filters depend on
1333config BPF
1334 bool
1335
David Rientjes6a108a12011-01-20 14:44:16 -08001336menuconfig EXPERT
1337 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001338 # Unhide debug options, to make the on-by-default options visible
1339 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 help
1341 This option allows certain base kernel options and settings
1342 to be disabled or tweaked. This is for specialized
1343 environments which can tolerate a "non-standard" kernel.
1344 Only use this if you really know what you are doing.
1345
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001346config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001347 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001348 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001349 default y
1350 help
1351 This enables the legacy 16-bit UID syscall wrappers.
1352
Iulia Manda28138932015-04-15 16:16:41 -07001353config MULTIUSER
1354 bool "Multiple users, groups and capabilities support" if EXPERT
1355 default y
1356 help
1357 This option enables support for non-root users, groups and
1358 capabilities.
1359
1360 If you say N here, all processes will run with UID 0, GID 0, and all
1361 possible capabilities. Saying N here also compiles out support for
1362 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1363 setgid, and capset.
1364
1365 If unsure, say Y here.
1366
Fabian Frederickf6187762014-06-04 16:11:12 -07001367config SGETMASK_SYSCALL
1368 bool "sgetmask/ssetmask syscalls support" if EXPERT
1369 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1370 ---help---
1371 sys_sgetmask and sys_ssetmask are obsolete system calls
1372 no longer supported in libc but still enabled by default in some
1373 architectures.
1374
1375 If unsure, leave the default option here.
1376
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001377config SYSFS_SYSCALL
1378 bool "Sysfs syscall support" if EXPERT
1379 default y
1380 ---help---
1381 sys_sysfs is an obsolete system call no longer supported in libc.
1382 Note that disabling this option is more secure but might break
1383 compatibility with some systems.
1384
1385 If unsure say Y here.
1386
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001387config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001388 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001389 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001390 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001391 select SYSCTL
1392 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001393 sys_sysctl uses binary paths that have been found challenging
1394 to properly maintain and use. The interface in /proc/sys
1395 using paths with ascii names is now the primary path to this
1396 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001397
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001398 Almost nothing using the binary sysctl interface so if you are
1399 trying to save some space it is probably safe to disable this,
1400 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001401
WANG Congc736de62011-11-02 13:39:25 -07001402 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001403
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001405 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406 default y
1407 help
1408 Say Y here to let the kernel print out symbolic crash information and
1409 symbolic stack backtraces. This increases the size of the kernel
1410 somewhat, as all symbols have to be loaded into the kernel image.
1411
1412config KALLSYMS_ALL
1413 bool "Include all symbols in kallsyms"
1414 depends on DEBUG_KERNEL && KALLSYMS
1415 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001416 Normally kallsyms only contains the symbols of functions for nicer
1417 OOPS messages and backtraces (i.e., symbols from the text and inittext
1418 sections). This is sufficient for most cases. And only in very rare
1419 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1420 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001422 This option makes sure that all symbols are loaded into the kernel
1423 image (i.e., symbols from all sections) in cost of increased kernel
1424 size (depending on the kernel configuration, it may be 300KiB or
1425 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001427 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001428
1429config PRINTK
1430 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001431 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001432 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001433 help
1434 This option enables normal printk support. Removing it
1435 eliminates most of the message strings from the kernel image
1436 and makes the kernel more or less silent. As this makes it
1437 very difficult to diagnose system problems, saying N here is
1438 strongly discouraged.
1439
Matt Mackallc8538a72005-05-01 08:59:01 -07001440config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001441 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001442 default y
1443 help
1444 Disabling this option eliminates support for BUG and WARN, reducing
1445 the size of your kernel image and potentially quietly ignoring
1446 numerous fatal conditions. You should only consider disabling this
1447 option for embedded systems with no facilities for reporting errors.
1448 Just say Y.
1449
Matt Mackall708e9a72006-01-08 01:05:25 -08001450config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001451 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001452 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001453 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001454 help
1455 Enable support for generating core dumps. Disabling saves about 4k.
1456
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001457
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001458config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001459 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001460 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001461 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001462 default y
1463 help
1464 This option allows to disable the internal PC-Speaker
1465 support, saving some memory.
1466
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467config BASE_FULL
1468 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001469 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470 help
1471 Disabling this option reduces the size of miscellaneous core
1472 kernel data structures. This saves memory on small machines,
1473 but may reduce performance.
1474
1475config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001476 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001478 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 help
1480 Disabling this option will cause the kernel to be built without
1481 support for "fast userspace mutexes". The resulting kernel may not
1482 run glibc-based applications correctly.
1483
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001484config HAVE_FUTEX_CMPXCHG
1485 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001486 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001487 help
1488 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1489 is implemented and always working. This removes a couple of runtime
1490 checks.
1491
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001493 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001495 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 help
1497 Disabling this option will cause the kernel to be built without
1498 support for epoll family of system calls.
1499
Davide Libenzifba2afa2007-05-10 22:23:13 -07001500config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001501 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001502 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001503 default y
1504 help
1505 Enable the signalfd() system call that allows to receive signals
1506 on a file descriptor.
1507
1508 If unsure, say Y.
1509
Davide Libenzib215e282007-05-10 22:23:16 -07001510config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001511 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001512 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001513 default y
1514 help
1515 Enable the timerfd() system call that allows to receive timer
1516 events on a file descriptor.
1517
1518 If unsure, say Y.
1519
Davide Libenzie1ad7462007-05-10 22:23:19 -07001520config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001521 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001522 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001523 default y
1524 help
1525 Enable the eventfd() system call that allows to receive both
1526 kernel notification (ie. KAIO) or userspace notifications.
1527
1528 If unsure, say Y.
1529
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001530# syscall, maps, verifier
1531config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001532 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001533 select ANON_INODES
1534 select BPF
1535 default n
1536 help
1537 Enable the bpf() system call that allows to manipulate eBPF
1538 programs and maps via file descriptors.
1539
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001541 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 default y
1543 depends on MMU
1544 help
1545 The shmem is an internal filesystem used to manage shared memory.
1546 It is backed by swap and manages resource limits. It is also exported
1547 to userspace as tmpfs if TMPFS is enabled. Disabling this
1548 option replaces shmem and tmpfs with the much simpler ramfs code,
1549 which may be appropriate on small systems without swap.
1550
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001551config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001552 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001553 default y
1554 help
1555 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001556 by some high performance threaded applications. Disabling
1557 this option saves about 7k.
1558
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001559config ADVISE_SYSCALLS
1560 bool "Enable madvise/fadvise syscalls" if EXPERT
1561 default y
1562 help
1563 This option enables the madvise and fadvise syscalls, used by
1564 applications to advise the kernel about their future memory or file
1565 usage, improving performance. If building an embedded system where no
1566 applications use these syscalls, you can disable this option to save
1567 space.
1568
Mike Frysinger657a5202013-04-30 15:28:45 -07001569config PCI_QUIRKS
1570 default y
1571 bool "Enable PCI quirk workarounds" if EXPERT
1572 depends on PCI
1573 help
1574 This enables workarounds for various PCI chipset
1575 bugs/quirks. Disable this only if your target machine is
1576 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001577
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001578config EMBEDDED
1579 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001580 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001581 select EXPERT
1582 help
1583 This option should be enabled if compiling the kernel for
1584 an embedded system so certain expert options are available
1585 for configuration.
1586
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001587config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001588 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001589 help
1590 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001591
Peter Zijlstra906010b2009-09-21 16:08:49 +02001592config PERF_USE_VMALLOC
1593 bool
1594 help
1595 See tools/perf/design.txt for details
1596
Ingo Molnar57c0c152009-09-21 12:20:38 +02001597menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001598
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001599config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001600 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001601 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001602 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001603 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001604 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001605 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001606 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001607 Enable kernel support for various performance events provided
1608 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001609
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001610 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001611 use of generic tracepoints.
1612
1613 Most modern CPUs support performance events via performance
1614 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001615 types of hw events: such as instructions executed, cachemisses
1616 suffered, or branches mis-predicted - without slowing down the
1617 kernel or applications. These registers can also trigger interrupts
1618 when a threshold number of events have passed - and can thus be
1619 used to profile the code that runs on that CPU.
1620
Ingo Molnar57c0c152009-09-21 12:20:38 +02001621 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001622 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001623 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001624 provides per task and per CPU counters, and it provides event
1625 capabilities on top of those.
1626
1627 Say Y if unsure.
1628
Peter Zijlstra906010b2009-09-21 16:08:49 +02001629config DEBUG_PERF_USE_VMALLOC
1630 default n
1631 bool "Debug: use vmalloc to back perf mmap() buffers"
1632 depends on PERF_EVENTS && DEBUG_KERNEL
1633 select PERF_USE_VMALLOC
1634 help
1635 Use vmalloc memory to back perf mmap() buffers.
1636
1637 Mostly useful for debugging the vmalloc code on platforms
1638 that don't require it.
1639
1640 Say N if unsure.
1641
Thomas Gleixner0793a612008-12-04 20:12:29 +01001642endmenu
1643
Christoph Lameterf8891e52006-06-30 01:55:45 -07001644config VM_EVENT_COUNTERS
1645 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001646 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001647 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001648 VM event counters are needed for event counts to be shown.
1649 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001650 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001651 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001652
Christoph Lameter41ecc552007-05-09 02:32:44 -07001653config SLUB_DEBUG
1654 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001655 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001656 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001657 help
1658 SLUB has extensive debug support features. Disabling these can
1659 result in significant savings in code size. This also disables
1660 SLUB sysfs support. /sys/slab will not exist and there will be
1661 no support for cache validation etc.
1662
Randy Dunlapb943c462009-03-10 12:55:46 -07001663config COMPAT_BRK
1664 bool "Disable heap randomization"
1665 default y
1666 help
1667 Randomizing heap placement makes heap exploits harder, but it
1668 also breaks ancient binaries (including anything libc5 based).
1669 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001670 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001671 /proc/sys/kernel/randomize_va_space to 2.
1672
1673 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1674
Christoph Lameter81819f02007-05-06 14:49:36 -07001675choice
1676 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001677 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001678 help
1679 This option allows to select a slab allocator.
1680
1681config SLAB
1682 bool "SLAB"
1683 help
1684 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001685 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001686 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001687
1688config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001689 bool "SLUB (Unqueued Allocator)"
1690 help
1691 SLUB is a slab allocator that minimizes cache line usage
1692 instead of managing queues of cached objects (SLAB approach).
1693 Per cpu caching is realized using slabs of objects instead
1694 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001695 and has enhanced diagnostics. SLUB is the default choice for
1696 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001697
1698config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001699 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001700 bool "SLOB (Simple Allocator)"
1701 help
Matt Mackall37291452008-02-04 22:29:38 -08001702 SLOB replaces the stock allocator with a drastically simpler
1703 allocator. SLOB is generally more space efficient but
1704 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001705
1706endchoice
1707
Joonsoo Kim345c9052013-06-19 14:05:52 +09001708config SLUB_CPU_PARTIAL
1709 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001710 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001711 bool "SLUB per cpu partial cache"
1712 help
1713 Per cpu partial caches accellerate objects allocation and freeing
1714 that is local to a processor at the price of more indeterminism
1715 in the latency of the free. On overflow these caches will be cleared
1716 which requires the taking of locks that may cause latency spikes.
1717 Typically one would choose no for a realtime system.
1718
Jie Zhangea637632009-12-14 18:00:02 -08001719config MMAP_ALLOW_UNINITIALIZED
1720 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001721 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001722 default n
1723 help
1724 Normally, and according to the Linux spec, anonymous memory obtained
1725 from mmap() has it's contents cleared before it is passed to
1726 userspace. Enabling this config option allows you to request that
1727 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1728 providing a huge performance boost. If this option is not enabled,
1729 then the flag will be ignored.
1730
1731 This is taken advantage of by uClibc's malloc(), and also by
1732 ELF-FDPIC binfmt's brk and stack allocator.
1733
1734 Because of the obvious security issues, this option should only be
1735 enabled on embedded devices where you control what is run in
1736 userspace. Since that isn't generally a problem on no-MMU systems,
1737 it is normally safe to say Y here.
1738
1739 See Documentation/nommu-mmap.txt for more information.
1740
Peter Foley82c04ff2014-04-18 15:07:11 -07001741config SYSTEM_TRUSTED_KEYRING
1742 bool "Provide system-wide ring of trusted keys"
1743 depends on KEYS
1744 help
1745 Provide a system keyring to which trusted keys can be added. Keys in
1746 the keyring are considered to be trusted. Keys may be added at will
1747 by the kernel from compiled-in data and from hardware key stores, but
1748 userspace may only add extra keys if those keys can be verified by
1749 keys already in the keyring.
1750
1751 Keys in this keyring are used by module signature checking.
1752
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001753config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001754 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001755 help
1756 Say Y here to enable the extended profiling support mechanisms used
1757 by profilers such as OProfile.
1758
Ingo Molnar5f87f112008-07-23 14:15:22 +02001759#
1760# Place an empty function call at each tracepoint site. Can be
1761# dynamically changed for a probe function.
1762#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001763config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001764 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001765
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001766source "arch/Kconfig"
1767
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768endmenu # General setup
1769
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001770config HAVE_GENERIC_DMA_COHERENT
1771 bool
1772 default n
1773
Linus Torvalds158a9622008-01-02 13:04:48 -08001774config SLABINFO
1775 bool
1776 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001777 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001778 default y
1779
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001780config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001781 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001782
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783config BASE_SMALL
1784 int
1785 default 0 if BASE_FULL
1786 default 1 if !BASE_FULL
1787
Jan Engelhardt66da5732007-07-15 23:39:29 -07001788menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001790 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 help
1792 Kernel modules are small pieces of compiled code which can
1793 be inserted in the running kernel, rather than being
1794 permanently built into the kernel. You use the "modprobe"
1795 tool to add (and sometimes remove) them. If you say Y here,
1796 many parts of the kernel can be built as modules (by
1797 answering M instead of Y where indicated): this is most
1798 useful for infrequently used options which are not required
1799 for booting. For more information, see the man pages for
1800 modprobe, lsmod, modinfo, insmod and rmmod.
1801
1802 If you say Y here, you will need to run "make
1803 modules_install" to put the modules under /lib/modules/
1804 where modprobe can find them (you may need to be root to do
1805 this).
1806
1807 If unsure, say Y.
1808
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001809if MODULES
1810
Linus Torvalds826e4502008-05-04 17:04:16 -07001811config MODULE_FORCE_LOAD
1812 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001813 default n
1814 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001815 Allow loading of modules without version information (ie. modprobe
1816 --force). Forced module loading sets the 'F' (forced) taint flag and
1817 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001818
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819config MODULE_UNLOAD
1820 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 help
1822 Without this option you will not be able to unload any
1823 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001824 anyway), which makes your kernel smaller, faster
1825 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826
1827config MODULE_FORCE_UNLOAD
1828 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001829 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001830 help
1831 This option allows you to force a module to unload, even if the
1832 kernel believes it is unsafe: the kernel will remove the module
1833 without waiting for anyone to stop using it (using the -f option to
1834 rmmod). This is mainly for kernel developers and desperate users.
1835 If unsure, say N.
1836
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001838 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839 help
1840 Usually, you have to use modules compiled with your kernel.
1841 Saying Y here makes it sometimes possible to use modules
1842 compiled for different kernels, by adding enough information
1843 to the modules to (hopefully) spot any changes which would
1844 make them incompatible with the kernel you are running. If
1845 unsure, say N.
1846
1847config MODULE_SRCVERSION_ALL
1848 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 help
1850 Modules which contain a MODULE_VERSION get an extra "srcversion"
1851 field inserted into their modinfo section, which contains a
1852 sum of the source files which made it. This helps maintainers
1853 see exactly which source was used to build a module (since
1854 others sometimes change the module source without updating
1855 the version). With this option, such a "srcversion" field
1856 will be created for all modules. If unsure, say N.
1857
Rusty Russell106a4ee2012-09-26 10:09:40 +01001858config MODULE_SIG
1859 bool "Module signature verification"
1860 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001861 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001862 select KEYS
1863 select CRYPTO
1864 select ASYMMETRIC_KEY_TYPE
1865 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1866 select PUBLIC_KEY_ALGO_RSA
1867 select ASN1
1868 select OID_REGISTRY
1869 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001870 help
1871 Check modules for valid signatures upon load: the signature
1872 is simply appended to the module. For more information see
1873 Documentation/module-signing.txt.
1874
David Howellsea0b6dc2012-09-26 10:09:50 +01001875 !!!WARNING!!! If you enable this option, you MUST make sure that the
1876 module DOES NOT get stripped after being signed. This includes the
1877 debuginfo strip done by some packagers (such as rpmbuild) and
1878 inclusion into an initramfs that wants the module size reduced.
1879
Rusty Russell106a4ee2012-09-26 10:09:40 +01001880config MODULE_SIG_FORCE
1881 bool "Require modules to be validly signed"
1882 depends on MODULE_SIG
1883 help
1884 Reject unsigned modules or signed modules for which we don't have a
1885 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001886
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301887config MODULE_SIG_ALL
1888 bool "Automatically sign all modules"
1889 default y
1890 depends on MODULE_SIG
1891 help
1892 Sign all modules during make modules_install. Without this option,
1893 modules must be signed manually, using the scripts/sign-file tool.
1894
1895comment "Do not forget to sign required modules with scripts/sign-file"
1896 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1897
David Howellsea0b6dc2012-09-26 10:09:50 +01001898choice
1899 prompt "Which hash algorithm should modules be signed with?"
1900 depends on MODULE_SIG
1901 help
1902 This determines which sort of hashing algorithm will be used during
1903 signature generation. This algorithm _must_ be built into the kernel
1904 directly so that signature verification can take place. It is not
1905 possible to load a signed module containing the algorithm to check
1906 the signature on that module.
1907
1908config MODULE_SIG_SHA1
1909 bool "Sign modules with SHA-1"
1910 select CRYPTO_SHA1
1911
1912config MODULE_SIG_SHA224
1913 bool "Sign modules with SHA-224"
1914 select CRYPTO_SHA256
1915
1916config MODULE_SIG_SHA256
1917 bool "Sign modules with SHA-256"
1918 select CRYPTO_SHA256
1919
1920config MODULE_SIG_SHA384
1921 bool "Sign modules with SHA-384"
1922 select CRYPTO_SHA512
1923
1924config MODULE_SIG_SHA512
1925 bool "Sign modules with SHA-512"
1926 select CRYPTO_SHA512
1927
1928endchoice
1929
Michal Marek22753672013-01-25 13:41:00 +10301930config MODULE_SIG_HASH
1931 string
1932 depends on MODULE_SIG
1933 default "sha1" if MODULE_SIG_SHA1
1934 default "sha224" if MODULE_SIG_SHA224
1935 default "sha256" if MODULE_SIG_SHA256
1936 default "sha384" if MODULE_SIG_SHA384
1937 default "sha512" if MODULE_SIG_SHA512
1938
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301939config MODULE_COMPRESS
1940 bool "Compress modules on installation"
1941 depends on MODULES
1942 help
1943 This option compresses the kernel modules when 'make
1944 modules_install' is run.
1945
1946 The modules will be compressed either using gzip or xz depend on the
1947 choice made in "Compression algorithm".
1948
1949 module-init-tools has support for gzip format while kmod handle gzip
1950 and xz compressed modules.
1951
1952 When a kernel module is installed from outside of the main kernel
1953 source and uses the Kbuild system for installing modules then that
1954 kernel module will also be compressed when it is installed.
1955
1956 This option provides little benefit when the modules are to be used inside
1957 an initrd or initramfs, it generally is more efficient to compress the whole
1958 initrd or initramfs instead.
1959
1960 This is fully compatible with signed modules while the signed module is
1961 compressed. module-init-tools or kmod handles decompression and provide to
1962 other layer the uncompressed but signed payload.
1963
1964choice
1965 prompt "Compression algorithm"
1966 depends on MODULE_COMPRESS
1967 default MODULE_COMPRESS_GZIP
1968 help
1969 This determines which sort of compression will be used during
1970 'make modules_install'.
1971
1972 GZIP (default) and XZ are supported.
1973
1974config MODULE_COMPRESS_GZIP
1975 bool "GZIP"
1976
1977config MODULE_COMPRESS_XZ
1978 bool "XZ"
1979
1980endchoice
1981
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001982endif # MODULES
1983
Rusty Russell98a79d62008-12-13 21:19:41 +10301984config INIT_ALL_POSSIBLE
1985 bool
1986 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301987 Back when each arch used to define their own cpu_online_mask and
1988 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301989 with all 1s, and others with all 0s. When they were centralised,
1990 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001991 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301992
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993config STOP_MACHINE
1994 bool
1995 default y
1996 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1997 help
1998 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001999
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002000source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07002001
2002config PREEMPT_NOTIFIERS
2003 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01002004
Steffen Klassert16295be2010-01-06 19:47:10 +11002005config PADATA
2006 depends on SMP
2007 bool
2008
Andi Kleen754b7b62012-10-04 17:11:27 -07002009# Can be selected by architectures with broken toolchains
2010# that get confused by correct const<->read_only section
2011# mappings
2012config BROKEN_RODATA
2013 bool
2014
David Howells4520c6a2012-09-21 23:31:13 +01002015config ASN1
2016 tristate
2017 help
2018 Build a simple ASN.1 grammar compiler that produces a bytecode output
2019 that can be interpreted by the ASN.1 stream decoder and used to
2020 inform it as to what tags are to be expected in a stream and what
2021 functions to call on what tags.
2022
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002023source "kernel/Kconfig.locks"