blob: b999fa381bf9fe1f37757af5e0a454cc6adb2da9 [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
Mike Travisc903ff82009-01-15 12:28:29 -0800468config TREE_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400469 bool
470 default y if !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800471 help
472 This option selects the RCU implementation that is
473 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700474 thousands of CPUs. It also scales down nicely to
475 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800476
Pranith Kumar28f65692014-09-22 14:00:48 -0400477config PREEMPT_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400478 bool
479 default y if PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700480 help
481 This option selects the RCU implementation that is
482 designed for very large SMP systems with hundreds or
483 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700484 is also required. It also scales down nicely to
485 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700486
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800487 Select this option if you are unsure.
488
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700489config TINY_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400490 bool
491 default y if !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700492 help
493 This option selects the RCU implementation that is
494 designed for UP systems from which real-time response
495 is not required. This option greatly reduces the
496 memory footprint of RCU.
497
Paul E. McKenney78cae102015-04-20 12:19:45 -0700498config RCU_EXPERT
499 bool "Make expert-level adjustments to RCU configuration"
500 default n
501 help
502 This option needs to be enabled if you wish to make
503 expert-level adjustments to RCU configuration. By default,
504 no such adjustments can be made, which has the often-beneficial
505 side-effect of preventing "make oldconfig" from asking you all
506 sorts of detailed questions about how you would like numerous
507 obscure RCU options to be set up.
508
509 Say Y if you need to make expert-level adjustments to RCU.
510
511 Say N if you are unsure.
512
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500513config SRCU
514 bool
515 help
516 This option selects the sleepable version of RCU. This version
517 permits arbitrary sleeping or blocking within RCU read-side critical
518 sections.
519
Paul E. McKenney8315f422014-06-27 13:42:20 -0700520config TASKS_RCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -0700521 bool
Paul E. McKenney8315f422014-06-27 13:42:20 -0700522 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500523 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700524 help
525 This option enables a task-based RCU implementation that uses
526 only voluntary context switch (not preemption!), idle, and
527 user-mode execution as quiescent states.
528
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700529config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400530 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700531 help
532 This option enables RCU CPU stall code that is common between
533 the TINY and TREE variants of RCU. The purpose is to allow
534 the tiny variants to disable RCU CPU stall warnings, while
535 making these warnings mandatory for the tree variants.
536
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100537config CONTEXT_TRACKING
538 bool
539
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200540config RCU_USER_QS
Paul E. McKenney7db21ed2015-04-20 06:17:15 -0700541 bool
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200542 help
543 This option sets hooks on kernel / userspace boundaries and
544 puts RCU in extended quiescent state when the CPU runs in
545 userspace. It means that when a CPU runs in userspace, it is
546 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700547 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200548
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100549config CONTEXT_TRACKING_FORCE
550 bool "Force context tracking"
551 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200552 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200553 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200554 The major pre-requirement for full dynticks to work is to
555 support the context tracking subsystem. But there are also
556 other dependencies to provide in order to make the full
557 dynticks working.
558
559 This option stands for testing when an arch implements the
560 context tracking backend but doesn't yet fullfill all the
561 requirements to make the full dynticks feature working.
562 Without the full dynticks, there is no way to test the support
563 for context tracking and the subsystems that rely on it: RCU
564 userspace extended quiescent state and tickless cputime
565 accounting. This option copes with the absence of the full
566 dynticks subsystem by forcing the context tracking on all
567 CPUs in the system.
568
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400569 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200570 architecture backend for the context tracking.
571
572 Say N otherwise, this option brings an overhead that you
573 don't want in production.
574
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200575
Mike Travisc903ff82009-01-15 12:28:29 -0800576config RCU_FANOUT
577 int "Tree-based hierarchical RCU fanout value"
578 range 2 64 if 64BIT
579 range 2 32 if !64BIT
Paul E. McKenney05c5df32015-04-20 14:27:43 -0700580 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Mike Travisc903ff82009-01-15 12:28:29 -0800581 default 64 if 64BIT
582 default 32 if !64BIT
583 help
584 This option controls the fanout of hierarchical implementations
585 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700586 large numbers of CPUs. This value must be at least the fourth
587 root of NR_CPUS, which allows NR_CPUS to be insanely large.
588 The default value of RCU_FANOUT should be used for production
589 systems, but if you are stress-testing the RCU implementation
590 itself, small RCU_FANOUT values allow you to test large-system
591 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800592
593 Select a specific number if testing RCU itself.
594 Take the default if unsure.
595
Paul E. McKenney8932a632012-04-19 12:20:14 -0700596config RCU_FANOUT_LEAF
597 int "Tree-based hierarchical RCU leaf-level fanout value"
Paul E. McKenney8739c5c2015-04-20 18:27:54 -0700598 range 2 64 if 64BIT
599 range 2 32 if !64BIT
Paul E. McKenney47d631a2015-04-21 09:12:13 -0700600 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Paul E. McKenney8932a632012-04-19 12:20:14 -0700601 default 16
602 help
603 This option controls the leaf-level fanout of hierarchical
604 implementations of RCU, and allows trading off cache misses
605 against lock contention. Systems that synchronize their
606 scheduling-clock interrupts for energy-efficiency reasons will
607 want the default because the smaller leaf-level fanout keeps
608 lock contention levels acceptably low. Very large systems
609 (hundreds or thousands of CPUs) will instead want to set this
610 value to the maximum value possible in order to reduce the
611 number of cache misses incurred during RCU's grace-period
612 initialization. These systems tend to run CPU-bound, and thus
613 are not helped by synchronized interrupts, and thus tend to
614 skew them, which reduces lock contention enough that large
615 leaf-level fanouts work well.
616
617 Select a specific number if testing RCU itself.
618
619 Select the maximum permissible value for large systems.
620
621 Take the default if unsure.
622
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800623config RCU_FAST_NO_HZ
624 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700625 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800626 default n
627 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800628 This option permits CPUs to enter dynticks-idle state even if
629 they have RCU callbacks queued, and prevents RCU from waking
630 these CPUs up more than roughly once every four jiffies (by
631 default, you can adjust this using the rcutree.rcu_idle_gp_delay
632 parameter), thus improving energy efficiency. On the other
633 hand, this option increases the duration of RCU grace periods,
634 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800635
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800636 Say Y if energy efficiency is critically important, and you
637 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800638
639 Say N if you are unsure.
640
Mike Travisc903ff82009-01-15 12:28:29 -0800641config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400642 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800643 select DEBUG_FS
644 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700645 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400646 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700647 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800648
Paul E. McKenney24278d12010-09-27 17:25:23 -0700649config RCU_BOOST
650 bool "Enable RCU priority boosting"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700651 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700652 default n
653 help
654 This option boosts the priority of preempted RCU readers that
655 block the current preemptible RCU grace period for too long.
656 This option also prevents heavy loads from blocking RCU
657 callback invocation for all flavors of RCU.
658
659 Say Y here if you are working with real-time apps or heavy loads
660 Say N here if you are unsure.
661
Clark Williams21871d72014-09-12 21:21:09 -0500662config RCU_KTHREAD_PRIO
663 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800664 range 1 99 if RCU_BOOST
665 range 0 99 if !RCU_BOOST
666 default 1 if RCU_BOOST
667 default 0 if !RCU_BOOST
Paul E. McKenney26730f52015-04-21 09:22:14 -0700668 depends on RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700669 help
Clark Williams21871d72014-09-12 21:21:09 -0500670 This option specifies the SCHED_FIFO priority value that will be
671 assigned to the rcuc/n and rcub/n threads and is also the value
672 used for RCU_BOOST (if enabled). If you are working with a
673 real-time application that has one or more CPU-bound threads
674 running at a real-time priority level, you should set
675 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
676 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
677 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700678 applications that do not have any CPU-bound threads.
679
680 Some real-time applications might not have a single real-time
681 thread that saturates a given CPU, but instead might have
682 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500683 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700684 a priority higher than the lowest-priority thread that is
685 conspiring to prevent the CPU from running any non-real-time
686 tasks. For example, if one thread at priority 10 and another
687 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500688 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700689 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700690
691 Specify the real-time priority, or take the default if unsure.
692
693config RCU_BOOST_DELAY
694 int "Milliseconds to delay boosting after RCU grace-period start"
695 range 0 3000
696 depends on RCU_BOOST
697 default 500
698 help
699 This option specifies the time to wait after the beginning of
700 a given grace period before priority-boosting preempted RCU
701 readers blocking that grace period. Note that any RCU reader
702 blocking an expedited RCU grace period is boosted immediately.
703
704 Accept the default if unsure.
705
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700706config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700707 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400708 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700709 default n
710 help
711 Use this option to reduce OS jitter for aggressive HPC or
712 real-time workloads. It can also be used to offload RCU
713 callback invocation to energy-efficient CPUs in battery-powered
714 asymmetric multiprocessors.
715
716 This option offloads callback invocation from the set of
717 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800718 For each such CPU, a kthread ("rcuox/N") will be created to
719 invoke callbacks, where the "N" is the CPU being offloaded,
720 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
721 "s" for RCU-sched. Nothing prevents this kthread from running
722 on the specified CPUs, but (1) the kthreads may be preempted
723 between each callback, and (2) affinity or cgroups can be used
724 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700725
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800726 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700727 Say N here if you are unsure.
728
Paul E. McKenney911af502013-02-11 10:23:27 -0800729choice
730 prompt "Build-forced no-CBs CPUs"
731 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200732 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800733 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700734 This option allows no-CBs CPUs (whose RCU callbacks are invoked
735 from kthreads rather than from softirq context) to be specified
736 at build time. Additional no-CBs CPUs may be specified by
737 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800738
739config RCU_NOCB_CPU_NONE
740 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800741 help
742 This option does not force any of the CPUs to be no-CBs CPUs.
743 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700744 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
745 kthreads whose names begin with "rcuo". All other CPUs will
746 invoke their own RCU callbacks in softirq context.
747
748 Select this option if you want to choose no-CBs CPUs at
749 boot time, for example, to allow testing of different no-CBs
750 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800751
752config RCU_NOCB_CPU_ZERO
753 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800754 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700755 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
756 callbacks are invoked by a per-CPU kthread whose name begins
757 with "rcuo". Additional CPUs may be designated as no-CBs
758 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
759 All other CPUs will invoke their own RCU callbacks in softirq
760 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800761
762 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700763 or energy-efficiency reasons, but the real reason it exists
764 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800765
766config RCU_NOCB_CPU_ALL
767 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800768 help
769 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700770 boot parameter will be ignored. All CPUs' RCU callbacks will
771 be executed in the context of per-CPU rcuo kthreads created for
772 this purpose. Assuming that the kthreads whose names start with
773 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
774 on the remaining CPUs, but might decrease memory locality during
775 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800776
777 Select this if all CPUs need to be no-CBs CPUs for real-time
778 or energy-efficiency reasons.
779
780endchoice
781
Paul E. McKenneyee425712015-02-19 10:51:32 -0800782config RCU_EXPEDITE_BOOT
783 bool
784 default n
785 help
786 This option enables expedited grace periods at boot time,
787 as if rcu_expedite_gp() had been invoked early in boot.
788 The corresponding rcu_unexpedite_gp() is invoked from
789 rcu_end_inkernel_boot(), which is intended to be invoked
790 at the end of the kernel-only boot sequence, just before
791 init is exec'ed.
792
793 Accept the default if unsure.
794
Mike Travisc903ff82009-01-15 12:28:29 -0800795endmenu # "RCU Subsystem"
796
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700797config BUILD_BIN2C
798 bool
799 default n
800
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700802 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700803 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 ---help---
805 This option enables the complete Linux kernel ".config" file
806 contents to be saved in the kernel. It provides documentation
807 of which kernel options are used in a running kernel or in an
808 on-disk kernel. This information can be extracted from the kernel
809 image file with the script scripts/extract-ikconfig and used as
810 input to rebuild the current kernel or to build another kernel.
811 It can also be extracted from a running kernel by reading
812 /proc/config.gz if enabled (below).
813
814config IKCONFIG_PROC
815 bool "Enable access to .config through /proc/config.gz"
816 depends on IKCONFIG && PROC_FS
817 ---help---
818 This option enables access to the kernel configuration file
819 through /proc/config.gz.
820
Alistair John Strachan794543a2007-05-08 00:31:15 -0700821config LOG_BUF_SHIFT
822 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
823 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700824 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700825 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700826 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700827 Select the minimal kernel log buffer size as a power of 2.
828 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
829 parameter, see below. Any higher size also might be forced
830 by "log_buf_len" boot parameter.
831
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700832 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700833 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700834 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700835 15 => 32 KB
836 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700837 13 => 8 KB
838 12 => 4 KB
839
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700840config LOG_CPU_MAX_BUF_SHIFT
841 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700842 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700843 range 0 21
844 default 12 if !BASE_SMALL
845 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700846 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700847 help
848 This option allows to increase the default ring buffer size
849 according to the number of CPUs. The value defines the contribution
850 of each CPU as a power of 2. The used space is typically only few
851 lines however it might be much more when problems are reported,
852 e.g. backtraces.
853
854 The increased size means that a new buffer has to be allocated and
855 the original static one is unused. It makes sense only on systems
856 with more CPUs. Therefore this value is used only when the sum of
857 contributions is greater than the half of the default kernel ring
858 buffer as defined by LOG_BUF_SHIFT. The default values are set
859 so that more than 64 CPUs are needed to trigger the allocation.
860
861 Also this option is ignored when "log_buf_len" kernel parameter is
862 used as it forces an exact (power of two) size of the ring buffer.
863
864 The number of possible CPUs is used for this computation ignoring
865 hotplugging making the compuation optimal for the the worst case
866 scenerio while allowing a simple algorithm to be used from bootup.
867
868 Examples shift values and their meaning:
869 17 => 128 KB for each CPU
870 16 => 64 KB for each CPU
871 15 => 32 KB for each CPU
872 14 => 16 KB for each CPU
873 13 => 8 KB for each CPU
874 12 => 4 KB for each CPU
875
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800876#
877# Architectures with an unreliable sched_clock() should select this:
878#
879config HAVE_UNSTABLE_SCHED_CLOCK
880 bool
881
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700882config GENERIC_SCHED_CLOCK
883 bool
884
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200885#
886# For architectures that want to enable the support for NUMA-affine scheduler
887# balancing logic:
888#
889config ARCH_SUPPORTS_NUMA_BALANCING
890 bool
891
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100892#
893# For architectures that know their GCC __int128 support is sound
894#
895config ARCH_SUPPORTS_INT128
896 bool
897
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200898# For architectures that (ab)use NUMA to represent different memory regions
899# all cpu-local but of different latencies, such as SuperH.
900#
901config ARCH_WANT_NUMA_VARIABLE_LOCALITY
902 bool
903
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904config NUMA_BALANCING
905 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200906 depends on ARCH_SUPPORTS_NUMA_BALANCING
907 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
908 depends on SMP && NUMA && MIGRATION
909 help
910 This option adds support for automatic NUMA aware memory/task placement.
911 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400912 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200913
914 This system will be inactive on UMA systems.
915
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800916config NUMA_BALANCING_DEFAULT_ENABLED
917 bool "Automatically enable NUMA aware memory/task placement"
918 default y
919 depends on NUMA_BALANCING
920 help
921 If set, automatic NUMA balancing will be enabled if running on a NUMA
922 machine.
923
Li Zefan23964d22009-01-15 13:50:58 -0800924menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500925 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500926 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700927 help
Li Zefan23964d22009-01-15 13:50:58 -0800928 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800929 use with process control subsystems such as Cpusets, CFS, memory
930 controls or device isolation.
931 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800932 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800933 - Documentation/cgroups/ (features for grouping, isolation
934 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700935
936 Say N if unsure.
937
Li Zefan23964d22009-01-15 13:50:58 -0800938if CGROUPS
939
Paul Menage006cb992007-10-18 23:39:43 -0700940config CGROUP_DEBUG
941 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700942 default n
Paul Menage006cb992007-10-18 23:39:43 -0700943 help
944 This option enables a simple cgroup subsystem that
945 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800946 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700947
Li Zefan23964d22009-01-15 13:50:58 -0800948 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700949
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700950config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800951 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800952 help
953 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700954 cgroup.
955
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700956config CGROUP_DEVICE
957 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700958 help
959 Provides a cgroup implementing whitelists for devices which
960 a process in the cgroup can mknod or open.
961
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962config CPUSETS
963 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700965 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 allow dynamically partitioning a system into sets of CPUs and
967 Memory Nodes and assigning tasks to run only within those sets.
968 This is primarily useful on large SMP or NUMA systems.
969
970 Say N if unsure.
971
Li Zefan23964d22009-01-15 13:50:58 -0800972config PROC_PID_CPUSET
973 bool "Include legacy /proc/<pid>/cpuset file"
974 depends on CPUSETS
975 default y
976
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100977config CGROUP_CPUACCT
978 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100979 help
980 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800981 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100982
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800983config PAGE_COUNTER
984 bool
985
Andrew Mortonc255a452012-07-31 16:43:02 -0700986config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800987 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800988 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500989 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800990 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700991 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100992 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800993
Andrew Mortonc255a452012-07-31 16:43:02 -0700994config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700995 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700996 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800997 help
998 Add swap management feature to memory resource controller. When you
999 enable this, you can limit mem+swap usage per cgroup. In other words,
1000 when you disable this, memory resource controller has no cares to
1001 usage of swap...a process can exhaust all of the swap. This extension
1002 is useful when you want to avoid exhaustion swap but this itself
1003 adds more overheads and consumes memory for remembering information.
1004 Especially if you use 32bit system or small memory system, please
1005 be careful about enabling this. When memory resource controller
1006 is disabled by boot option, this will be automatically disabled and
1007 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001008 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001009 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1010 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001011config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001012 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001013 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001014 default y
1015 help
1016 Memory Resource Controller Swap Extension comes with its price in
1017 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001018 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001019 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001020 parameter should have this option unselected.
1021 For those who want to have the feature enabled by default should
1022 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001023 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001024config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001025 bool "Memory Resource Controller Kernel Memory accounting"
1026 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001027 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001028 help
1029 The Kernel Memory extension for Memory Resource Controller can limit
1030 the amount of memory used by kernel objects in the system. Those are
1031 fundamentally different from the entities handled by the standard
1032 Memory Controller, which are page-based, and can be swapped. Users of
1033 the kmem extension can use it to guarantee that no group of processes
1034 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001035
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001036config CGROUP_HUGETLB
1037 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001038 depends on HUGETLB_PAGE
1039 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001040 default n
1041 help
1042 Provides a cgroup Resource Controller for HugeTLB pages.
1043 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1044 The limit is enforced during page fault. Since HugeTLB doesn't
1045 support page reclaim, enforcing the limit at page fault time implies
1046 that, the application will get SIGBUS signal if it tries to access
1047 HugeTLB pages beyond its limit. This requires the application to know
1048 beforehand how much HugeTLB pages it would require for its use. The
1049 control group is tracked in the third page lru pointer. This means
1050 that we cannot use the controller with huge page less than 3 pages.
1051
Stephane Eraniane5d13672011-02-14 11:20:01 +02001052config CGROUP_PERF
1053 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1054 depends on PERF_EVENTS && CGROUPS
1055 help
1056 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001057 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001058 designated cpu.
1059
1060 Say N if unsure.
1061
Dhaval Giani7c941432010-01-20 13:26:18 +01001062menuconfig CGROUP_SCHED
1063 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001064 default n
1065 help
1066 This feature lets CPU scheduler recognize task groups and control CPU
1067 bandwidth allocation to such task groups. It uses cgroups to group
1068 tasks.
1069
1070if CGROUP_SCHED
1071config FAIR_GROUP_SCHED
1072 bool "Group scheduling for SCHED_OTHER"
1073 depends on CGROUP_SCHED
1074 default CGROUP_SCHED
1075
Paul Turnerab84d312011-07-21 09:43:28 -07001076config CFS_BANDWIDTH
1077 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001078 depends on FAIR_GROUP_SCHED
1079 default n
1080 help
1081 This option allows users to define CPU bandwidth rates (limits) for
1082 tasks running within the fair group scheduler. Groups with no limit
1083 set are considered to be unconstrained and will run with no
1084 restriction.
1085 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1086
Dhaval Giani7c941432010-01-20 13:26:18 +01001087config RT_GROUP_SCHED
1088 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001089 depends on CGROUP_SCHED
1090 default n
1091 help
1092 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001093 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001094 schedule realtime tasks for non-root users until you allocate
1095 realtime bandwidth for them.
1096 See Documentation/scheduler/sched-rt-group.txt for more information.
1097
1098endif #CGROUP_SCHED
1099
Vivek Goyalafc24d42010-04-26 19:27:56 +02001100config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001101 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001102 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001103 default n
1104 ---help---
1105 Generic block IO controller cgroup interface. This is the common
1106 cgroup interface which should be used by various IO controlling
1107 policies.
1108
1109 Currently, CFQ IO scheduler uses it to recognize task groups and
1110 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001111 to such task groups. It is also used by bio throttling logic in
1112 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001113
1114 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001115 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001116 enabling proportional weight division of disk bandwidth in CFQ, set
1117 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001118 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001119
1120 See Documentation/cgroups/blkio-controller.txt for more information.
1121
1122config DEBUG_BLK_CGROUP
1123 bool "Enable Block IO controller debugging"
1124 depends on BLK_CGROUP
1125 default n
1126 ---help---
1127 Enable some debugging help. Currently it exports additional stat
1128 files in a cgroup which can be useful for debugging.
1129
Li Zefan23964d22009-01-15 13:50:58 -08001130endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001131
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001132config CHECKPOINT_RESTORE
1133 bool "Checkpoint/restore support" if EXPERT
1134 default n
1135 help
1136 Enables additional kernel features in a sake of checkpoint/restore.
1137 In particular it adds auxiliary prctl codes to setup process text,
1138 data and heap segment sizes, and a few additional /proc filesystem
1139 entries.
1140
1141 If unsure, say N here.
1142
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001143menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001144 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001145 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001146 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001147 help
1148 Provides the way to make tasks work with different objects using
1149 the same id. For example same IPC id may refer to different objects
1150 or same user id or pid may refer to different tasks when used in
1151 different namespaces.
1152
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001153if NAMESPACES
1154
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001155config UTS_NS
1156 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001157 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001158 help
1159 In this namespace tasks see different info provided with the
1160 uname() system call
1161
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001162config IPC_NS
1163 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001164 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001165 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001166 help
1167 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001168 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001169
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001170config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001171 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001172 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001173 help
1174 This allows containers, i.e. vservers, to use user namespaces
1175 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001176
1177 When user namespaces are enabled in the kernel it is
1178 recommended that the MEMCG and MEMCG_KMEM options also be
1179 enabled and that user-space use the memory control groups to
1180 limit the amount of memory a memory unprivileged users can
1181 use.
1182
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001183 If unsure, say N.
1184
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001185config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001186 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001187 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001188 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001189 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001190 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001191 pid namespaces. This is a building block of containers.
1192
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001193config NET_NS
1194 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001195 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001196 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001197 help
1198 Allow user space to create what appear to be multiple instances
1199 of the network stack.
1200
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001201endif # NAMESPACES
1202
Mike Galbraith5091faa2010-11-30 14:18:03 +01001203config SCHED_AUTOGROUP
1204 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001205 select CGROUPS
1206 select CGROUP_SCHED
1207 select FAIR_GROUP_SCHED
1208 help
1209 This option optimizes the scheduler for common desktop workloads by
1210 automatically creating and populating task groups. This separation
1211 of workloads isolates aggressive CPU burners (like build jobs) from
1212 desktop applications. Task group autogeneration is currently based
1213 upon task session.
1214
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001215config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001216 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001217 depends on SYSFS
1218 default n
1219 help
1220 This option adds code that switches the layout of the "block" class
1221 devices, to not show up in /sys/class/block/, but only in
1222 /sys/block/.
1223
1224 This switch is only active when the sysfs.deprecated=1 boot option is
1225 passed or the SYSFS_DEPRECATED_V2 option is set.
1226
1227 This option allows new kernels to run on old distributions and tools,
1228 which might get confused by /sys/class/block/. Since 2007/2008 all
1229 major distributions and tools handle this just fine.
1230
1231 Recent distributions and userspace tools after 2009/2010 depend on
1232 the existence of /sys/class/block/, and will not work with this
1233 option enabled.
1234
1235 Only if you are using a new kernel on an old distribution, you might
1236 need to say Y here.
1237
1238config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001239 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001240 default n
1241 depends on SYSFS
1242 depends on SYSFS_DEPRECATED
1243 help
1244 Enable deprecated sysfs by default.
1245
1246 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1247 option.
1248
1249 Only if you are using a new kernel on an old distribution, you might
1250 need to say Y here. Even then, odds are you would not need it
1251 enabled, you can always pass the boot option if absolutely necessary.
1252
1253config RELAY
1254 bool "Kernel->user space relay support (formerly relayfs)"
1255 help
1256 This option enables support for relay interface support in
1257 certain file systems (such as debugfs).
1258 It is designed to provide an efficient mechanism for tools and
1259 facilities to relay large amounts of data from kernel space to
1260 user space.
1261
1262 If unsure, say N.
1263
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001264config BLK_DEV_INITRD
1265 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1266 depends on BROKEN || !FRV
1267 help
1268 The initial RAM filesystem is a ramfs which is loaded by the
1269 boot loader (loadlin or lilo) and that is mounted as root
1270 before the normal boot procedure. It is typically used to
1271 load modules needed to mount the "real" root file system,
1272 etc. See <file:Documentation/initrd.txt> for details.
1273
1274 If RAM disk support (BLK_DEV_RAM) is also included, this
1275 also enables initial RAM disk (initrd) support and adds
1276 15 Kbytes (more on some other architectures) to the kernel size.
1277
1278 If unsure say Y.
1279
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001280if BLK_DEV_INITRD
1281
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001282source "usr/Kconfig"
1283
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001284endif
1285
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001286config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001287 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001288 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001289 Enabling this option will pass "-Os" instead of "-O2" to
1290 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001291
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001292 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001293
Randy Dunlap08470622006-09-30 23:28:13 -07001294config SYSCTL
1295 bool
1296
Randy Dunlapb943c462009-03-10 12:55:46 -07001297config ANON_INODES
1298 bool
1299
Mike Frysinger657a5202013-04-30 15:28:45 -07001300config HAVE_UID16
1301 bool
1302
1303config SYSCTL_EXCEPTION_TRACE
1304 bool
1305 help
1306 Enable support for /proc/sys/debug/exception-trace.
1307
1308config SYSCTL_ARCH_UNALIGN_NO_WARN
1309 bool
1310 help
1311 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1312 Allows arch to define/use @no_unaligned_warning to possibly warn
1313 about unaligned access emulation going on under the hood.
1314
1315config SYSCTL_ARCH_UNALIGN_ALLOW
1316 bool
1317 help
1318 Enable support for /proc/sys/kernel/unaligned-trap
1319 Allows arches to define/use @unaligned_enabled to runtime toggle
1320 the unaligned access emulation.
1321 see arch/parisc/kernel/unaligned.c for reference
1322
Mike Frysinger657a5202013-04-30 15:28:45 -07001323config HAVE_PCSPKR_PLATFORM
1324 bool
1325
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001326# interpreter that classic socket filters depend on
1327config BPF
1328 bool
1329
David Rientjes6a108a12011-01-20 14:44:16 -08001330menuconfig EXPERT
1331 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001332 # Unhide debug options, to make the on-by-default options visible
1333 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 help
1335 This option allows certain base kernel options and settings
1336 to be disabled or tweaked. This is for specialized
1337 environments which can tolerate a "non-standard" kernel.
1338 Only use this if you really know what you are doing.
1339
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001340config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001341 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001342 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001343 default y
1344 help
1345 This enables the legacy 16-bit UID syscall wrappers.
1346
Iulia Manda28138932015-04-15 16:16:41 -07001347config MULTIUSER
1348 bool "Multiple users, groups and capabilities support" if EXPERT
1349 default y
1350 help
1351 This option enables support for non-root users, groups and
1352 capabilities.
1353
1354 If you say N here, all processes will run with UID 0, GID 0, and all
1355 possible capabilities. Saying N here also compiles out support for
1356 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1357 setgid, and capset.
1358
1359 If unsure, say Y here.
1360
Fabian Frederickf6187762014-06-04 16:11:12 -07001361config SGETMASK_SYSCALL
1362 bool "sgetmask/ssetmask syscalls support" if EXPERT
1363 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1364 ---help---
1365 sys_sgetmask and sys_ssetmask are obsolete system calls
1366 no longer supported in libc but still enabled by default in some
1367 architectures.
1368
1369 If unsure, leave the default option here.
1370
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001371config SYSFS_SYSCALL
1372 bool "Sysfs syscall support" if EXPERT
1373 default y
1374 ---help---
1375 sys_sysfs is an obsolete system call no longer supported in libc.
1376 Note that disabling this option is more secure but might break
1377 compatibility with some systems.
1378
1379 If unsure say Y here.
1380
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001381config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001382 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001383 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001384 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001385 select SYSCTL
1386 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001387 sys_sysctl uses binary paths that have been found challenging
1388 to properly maintain and use. The interface in /proc/sys
1389 using paths with ascii names is now the primary path to this
1390 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001391
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001392 Almost nothing using the binary sysctl interface so if you are
1393 trying to save some space it is probably safe to disable this,
1394 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001395
WANG Congc736de62011-11-02 13:39:25 -07001396 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001397
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001399 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 default y
1401 help
1402 Say Y here to let the kernel print out symbolic crash information and
1403 symbolic stack backtraces. This increases the size of the kernel
1404 somewhat, as all symbols have to be loaded into the kernel image.
1405
1406config KALLSYMS_ALL
1407 bool "Include all symbols in kallsyms"
1408 depends on DEBUG_KERNEL && KALLSYMS
1409 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001410 Normally kallsyms only contains the symbols of functions for nicer
1411 OOPS messages and backtraces (i.e., symbols from the text and inittext
1412 sections). This is sufficient for most cases. And only in very rare
1413 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1414 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001416 This option makes sure that all symbols are loaded into the kernel
1417 image (i.e., symbols from all sections) in cost of increased kernel
1418 size (depending on the kernel configuration, it may be 300KiB or
1419 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001421 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001422
1423config PRINTK
1424 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001425 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001426 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001427 help
1428 This option enables normal printk support. Removing it
1429 eliminates most of the message strings from the kernel image
1430 and makes the kernel more or less silent. As this makes it
1431 very difficult to diagnose system problems, saying N here is
1432 strongly discouraged.
1433
Matt Mackallc8538a72005-05-01 08:59:01 -07001434config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001435 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001436 default y
1437 help
1438 Disabling this option eliminates support for BUG and WARN, reducing
1439 the size of your kernel image and potentially quietly ignoring
1440 numerous fatal conditions. You should only consider disabling this
1441 option for embedded systems with no facilities for reporting errors.
1442 Just say Y.
1443
Matt Mackall708e9a72006-01-08 01:05:25 -08001444config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001445 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001446 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001447 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001448 help
1449 Enable support for generating core dumps. Disabling saves about 4k.
1450
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001451
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001452config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001453 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001454 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001455 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001456 default y
1457 help
1458 This option allows to disable the internal PC-Speaker
1459 support, saving some memory.
1460
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461config BASE_FULL
1462 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001463 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 help
1465 Disabling this option reduces the size of miscellaneous core
1466 kernel data structures. This saves memory on small machines,
1467 but may reduce performance.
1468
1469config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001470 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001472 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 help
1474 Disabling this option will cause the kernel to be built without
1475 support for "fast userspace mutexes". The resulting kernel may not
1476 run glibc-based applications correctly.
1477
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001478config HAVE_FUTEX_CMPXCHG
1479 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001480 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001481 help
1482 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1483 is implemented and always working. This removes a couple of runtime
1484 checks.
1485
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001487 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001489 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 help
1491 Disabling this option will cause the kernel to be built without
1492 support for epoll family of system calls.
1493
Davide Libenzifba2afa2007-05-10 22:23:13 -07001494config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001495 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001496 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001497 default y
1498 help
1499 Enable the signalfd() system call that allows to receive signals
1500 on a file descriptor.
1501
1502 If unsure, say Y.
1503
Davide Libenzib215e282007-05-10 22:23:16 -07001504config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001505 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001506 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001507 default y
1508 help
1509 Enable the timerfd() system call that allows to receive timer
1510 events on a file descriptor.
1511
1512 If unsure, say Y.
1513
Davide Libenzie1ad7462007-05-10 22:23:19 -07001514config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001515 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001516 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001517 default y
1518 help
1519 Enable the eventfd() system call that allows to receive both
1520 kernel notification (ie. KAIO) or userspace notifications.
1521
1522 If unsure, say Y.
1523
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001524# syscall, maps, verifier
1525config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001526 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001527 select ANON_INODES
1528 select BPF
1529 default n
1530 help
1531 Enable the bpf() system call that allows to manipulate eBPF
1532 programs and maps via file descriptors.
1533
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001535 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 default y
1537 depends on MMU
1538 help
1539 The shmem is an internal filesystem used to manage shared memory.
1540 It is backed by swap and manages resource limits. It is also exported
1541 to userspace as tmpfs if TMPFS is enabled. Disabling this
1542 option replaces shmem and tmpfs with the much simpler ramfs code,
1543 which may be appropriate on small systems without swap.
1544
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001545config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001546 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001547 default y
1548 help
1549 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001550 by some high performance threaded applications. Disabling
1551 this option saves about 7k.
1552
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001553config ADVISE_SYSCALLS
1554 bool "Enable madvise/fadvise syscalls" if EXPERT
1555 default y
1556 help
1557 This option enables the madvise and fadvise syscalls, used by
1558 applications to advise the kernel about their future memory or file
1559 usage, improving performance. If building an embedded system where no
1560 applications use these syscalls, you can disable this option to save
1561 space.
1562
Mike Frysinger657a5202013-04-30 15:28:45 -07001563config PCI_QUIRKS
1564 default y
1565 bool "Enable PCI quirk workarounds" if EXPERT
1566 depends on PCI
1567 help
1568 This enables workarounds for various PCI chipset
1569 bugs/quirks. Disable this only if your target machine is
1570 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001571
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001572config EMBEDDED
1573 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001574 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001575 select EXPERT
1576 help
1577 This option should be enabled if compiling the kernel for
1578 an embedded system so certain expert options are available
1579 for configuration.
1580
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001581config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001582 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001583 help
1584 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001585
Peter Zijlstra906010b2009-09-21 16:08:49 +02001586config PERF_USE_VMALLOC
1587 bool
1588 help
1589 See tools/perf/design.txt for details
1590
Ingo Molnar57c0c152009-09-21 12:20:38 +02001591menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001592
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001593config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001594 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001595 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001596 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001597 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001598 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001599 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001600 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001601 Enable kernel support for various performance events provided
1602 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001603
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001604 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001605 use of generic tracepoints.
1606
1607 Most modern CPUs support performance events via performance
1608 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001609 types of hw events: such as instructions executed, cachemisses
1610 suffered, or branches mis-predicted - without slowing down the
1611 kernel or applications. These registers can also trigger interrupts
1612 when a threshold number of events have passed - and can thus be
1613 used to profile the code that runs on that CPU.
1614
Ingo Molnar57c0c152009-09-21 12:20:38 +02001615 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001616 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001617 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001618 provides per task and per CPU counters, and it provides event
1619 capabilities on top of those.
1620
1621 Say Y if unsure.
1622
Peter Zijlstra906010b2009-09-21 16:08:49 +02001623config DEBUG_PERF_USE_VMALLOC
1624 default n
1625 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001626 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001627 select PERF_USE_VMALLOC
1628 help
1629 Use vmalloc memory to back perf mmap() buffers.
1630
1631 Mostly useful for debugging the vmalloc code on platforms
1632 that don't require it.
1633
1634 Say N if unsure.
1635
Thomas Gleixner0793a612008-12-04 20:12:29 +01001636endmenu
1637
Christoph Lameterf8891e52006-06-30 01:55:45 -07001638config VM_EVENT_COUNTERS
1639 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001640 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001641 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001642 VM event counters are needed for event counts to be shown.
1643 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001644 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001645 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001646
Christoph Lameter41ecc552007-05-09 02:32:44 -07001647config SLUB_DEBUG
1648 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001649 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001650 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001651 help
1652 SLUB has extensive debug support features. Disabling these can
1653 result in significant savings in code size. This also disables
1654 SLUB sysfs support. /sys/slab will not exist and there will be
1655 no support for cache validation etc.
1656
Randy Dunlapb943c462009-03-10 12:55:46 -07001657config COMPAT_BRK
1658 bool "Disable heap randomization"
1659 default y
1660 help
1661 Randomizing heap placement makes heap exploits harder, but it
1662 also breaks ancient binaries (including anything libc5 based).
1663 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001664 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001665 /proc/sys/kernel/randomize_va_space to 2.
1666
1667 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1668
Christoph Lameter81819f02007-05-06 14:49:36 -07001669choice
1670 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001671 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001672 help
1673 This option allows to select a slab allocator.
1674
1675config SLAB
1676 bool "SLAB"
1677 help
1678 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001679 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001680 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001681
1682config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001683 bool "SLUB (Unqueued Allocator)"
1684 help
1685 SLUB is a slab allocator that minimizes cache line usage
1686 instead of managing queues of cached objects (SLAB approach).
1687 Per cpu caching is realized using slabs of objects instead
1688 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001689 and has enhanced diagnostics. SLUB is the default choice for
1690 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001691
1692config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001693 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001694 bool "SLOB (Simple Allocator)"
1695 help
Matt Mackall37291452008-02-04 22:29:38 -08001696 SLOB replaces the stock allocator with a drastically simpler
1697 allocator. SLOB is generally more space efficient but
1698 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001699
1700endchoice
1701
Joonsoo Kim345c9052013-06-19 14:05:52 +09001702config SLUB_CPU_PARTIAL
1703 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001704 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001705 bool "SLUB per cpu partial cache"
1706 help
1707 Per cpu partial caches accellerate objects allocation and freeing
1708 that is local to a processor at the price of more indeterminism
1709 in the latency of the free. On overflow these caches will be cleared
1710 which requires the taking of locks that may cause latency spikes.
1711 Typically one would choose no for a realtime system.
1712
Jie Zhangea637632009-12-14 18:00:02 -08001713config MMAP_ALLOW_UNINITIALIZED
1714 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001715 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001716 default n
1717 help
1718 Normally, and according to the Linux spec, anonymous memory obtained
1719 from mmap() has it's contents cleared before it is passed to
1720 userspace. Enabling this config option allows you to request that
1721 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1722 providing a huge performance boost. If this option is not enabled,
1723 then the flag will be ignored.
1724
1725 This is taken advantage of by uClibc's malloc(), and also by
1726 ELF-FDPIC binfmt's brk and stack allocator.
1727
1728 Because of the obvious security issues, this option should only be
1729 enabled on embedded devices where you control what is run in
1730 userspace. Since that isn't generally a problem on no-MMU systems,
1731 it is normally safe to say Y here.
1732
1733 See Documentation/nommu-mmap.txt for more information.
1734
Peter Foley82c04ff2014-04-18 15:07:11 -07001735config SYSTEM_TRUSTED_KEYRING
1736 bool "Provide system-wide ring of trusted keys"
1737 depends on KEYS
1738 help
1739 Provide a system keyring to which trusted keys can be added. Keys in
1740 the keyring are considered to be trusted. Keys may be added at will
1741 by the kernel from compiled-in data and from hardware key stores, but
1742 userspace may only add extra keys if those keys can be verified by
1743 keys already in the keyring.
1744
1745 Keys in this keyring are used by module signature checking.
1746
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001747config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001748 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001749 help
1750 Say Y here to enable the extended profiling support mechanisms used
1751 by profilers such as OProfile.
1752
Ingo Molnar5f87f112008-07-23 14:15:22 +02001753#
1754# Place an empty function call at each tracepoint site. Can be
1755# dynamically changed for a probe function.
1756#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001757config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001758 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001759
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001760source "arch/Kconfig"
1761
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762endmenu # General setup
1763
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001764config HAVE_GENERIC_DMA_COHERENT
1765 bool
1766 default n
1767
Linus Torvalds158a9622008-01-02 13:04:48 -08001768config SLABINFO
1769 bool
1770 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001771 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001772 default y
1773
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001774config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001775 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001776
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777config BASE_SMALL
1778 int
1779 default 0 if BASE_FULL
1780 default 1 if !BASE_FULL
1781
Jan Engelhardt66da5732007-07-15 23:39:29 -07001782menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001784 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 help
1786 Kernel modules are small pieces of compiled code which can
1787 be inserted in the running kernel, rather than being
1788 permanently built into the kernel. You use the "modprobe"
1789 tool to add (and sometimes remove) them. If you say Y here,
1790 many parts of the kernel can be built as modules (by
1791 answering M instead of Y where indicated): this is most
1792 useful for infrequently used options which are not required
1793 for booting. For more information, see the man pages for
1794 modprobe, lsmod, modinfo, insmod and rmmod.
1795
1796 If you say Y here, you will need to run "make
1797 modules_install" to put the modules under /lib/modules/
1798 where modprobe can find them (you may need to be root to do
1799 this).
1800
1801 If unsure, say Y.
1802
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001803if MODULES
1804
Linus Torvalds826e4502008-05-04 17:04:16 -07001805config MODULE_FORCE_LOAD
1806 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001807 default n
1808 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001809 Allow loading of modules without version information (ie. modprobe
1810 --force). Forced module loading sets the 'F' (forced) taint flag and
1811 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001812
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813config MODULE_UNLOAD
1814 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 help
1816 Without this option you will not be able to unload any
1817 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001818 anyway), which makes your kernel smaller, faster
1819 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820
1821config MODULE_FORCE_UNLOAD
1822 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001823 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 help
1825 This option allows you to force a module to unload, even if the
1826 kernel believes it is unsafe: the kernel will remove the module
1827 without waiting for anyone to stop using it (using the -f option to
1828 rmmod). This is mainly for kernel developers and desperate users.
1829 If unsure, say N.
1830
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001832 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 help
1834 Usually, you have to use modules compiled with your kernel.
1835 Saying Y here makes it sometimes possible to use modules
1836 compiled for different kernels, by adding enough information
1837 to the modules to (hopefully) spot any changes which would
1838 make them incompatible with the kernel you are running. If
1839 unsure, say N.
1840
1841config MODULE_SRCVERSION_ALL
1842 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 help
1844 Modules which contain a MODULE_VERSION get an extra "srcversion"
1845 field inserted into their modinfo section, which contains a
1846 sum of the source files which made it. This helps maintainers
1847 see exactly which source was used to build a module (since
1848 others sometimes change the module source without updating
1849 the version). With this option, such a "srcversion" field
1850 will be created for all modules. If unsure, say N.
1851
Rusty Russell106a4ee2012-09-26 10:09:40 +01001852config MODULE_SIG
1853 bool "Module signature verification"
1854 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001855 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001856 select KEYS
1857 select CRYPTO
1858 select ASYMMETRIC_KEY_TYPE
1859 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1860 select PUBLIC_KEY_ALGO_RSA
1861 select ASN1
1862 select OID_REGISTRY
1863 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001864 help
1865 Check modules for valid signatures upon load: the signature
1866 is simply appended to the module. For more information see
1867 Documentation/module-signing.txt.
1868
David Howellsea0b6dc2012-09-26 10:09:50 +01001869 !!!WARNING!!! If you enable this option, you MUST make sure that the
1870 module DOES NOT get stripped after being signed. This includes the
1871 debuginfo strip done by some packagers (such as rpmbuild) and
1872 inclusion into an initramfs that wants the module size reduced.
1873
Rusty Russell106a4ee2012-09-26 10:09:40 +01001874config MODULE_SIG_FORCE
1875 bool "Require modules to be validly signed"
1876 depends on MODULE_SIG
1877 help
1878 Reject unsigned modules or signed modules for which we don't have a
1879 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001880
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301881config MODULE_SIG_ALL
1882 bool "Automatically sign all modules"
1883 default y
1884 depends on MODULE_SIG
1885 help
1886 Sign all modules during make modules_install. Without this option,
1887 modules must be signed manually, using the scripts/sign-file tool.
1888
1889comment "Do not forget to sign required modules with scripts/sign-file"
1890 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1891
David Howellsea0b6dc2012-09-26 10:09:50 +01001892choice
1893 prompt "Which hash algorithm should modules be signed with?"
1894 depends on MODULE_SIG
1895 help
1896 This determines which sort of hashing algorithm will be used during
1897 signature generation. This algorithm _must_ be built into the kernel
1898 directly so that signature verification can take place. It is not
1899 possible to load a signed module containing the algorithm to check
1900 the signature on that module.
1901
1902config MODULE_SIG_SHA1
1903 bool "Sign modules with SHA-1"
1904 select CRYPTO_SHA1
1905
1906config MODULE_SIG_SHA224
1907 bool "Sign modules with SHA-224"
1908 select CRYPTO_SHA256
1909
1910config MODULE_SIG_SHA256
1911 bool "Sign modules with SHA-256"
1912 select CRYPTO_SHA256
1913
1914config MODULE_SIG_SHA384
1915 bool "Sign modules with SHA-384"
1916 select CRYPTO_SHA512
1917
1918config MODULE_SIG_SHA512
1919 bool "Sign modules with SHA-512"
1920 select CRYPTO_SHA512
1921
1922endchoice
1923
Michal Marek22753672013-01-25 13:41:00 +10301924config MODULE_SIG_HASH
1925 string
1926 depends on MODULE_SIG
1927 default "sha1" if MODULE_SIG_SHA1
1928 default "sha224" if MODULE_SIG_SHA224
1929 default "sha256" if MODULE_SIG_SHA256
1930 default "sha384" if MODULE_SIG_SHA384
1931 default "sha512" if MODULE_SIG_SHA512
1932
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301933config MODULE_COMPRESS
1934 bool "Compress modules on installation"
1935 depends on MODULES
1936 help
1937 This option compresses the kernel modules when 'make
1938 modules_install' is run.
1939
1940 The modules will be compressed either using gzip or xz depend on the
1941 choice made in "Compression algorithm".
1942
1943 module-init-tools has support for gzip format while kmod handle gzip
1944 and xz compressed modules.
1945
1946 When a kernel module is installed from outside of the main kernel
1947 source and uses the Kbuild system for installing modules then that
1948 kernel module will also be compressed when it is installed.
1949
1950 This option provides little benefit when the modules are to be used inside
1951 an initrd or initramfs, it generally is more efficient to compress the whole
1952 initrd or initramfs instead.
1953
1954 This is fully compatible with signed modules while the signed module is
1955 compressed. module-init-tools or kmod handles decompression and provide to
1956 other layer the uncompressed but signed payload.
1957
1958choice
1959 prompt "Compression algorithm"
1960 depends on MODULE_COMPRESS
1961 default MODULE_COMPRESS_GZIP
1962 help
1963 This determines which sort of compression will be used during
1964 'make modules_install'.
1965
1966 GZIP (default) and XZ are supported.
1967
1968config MODULE_COMPRESS_GZIP
1969 bool "GZIP"
1970
1971config MODULE_COMPRESS_XZ
1972 bool "XZ"
1973
1974endchoice
1975
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001976endif # MODULES
1977
Rusty Russell98a79d62008-12-13 21:19:41 +10301978config INIT_ALL_POSSIBLE
1979 bool
1980 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301981 Back when each arch used to define their own cpu_online_mask and
1982 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301983 with all 1s, and others with all 0s. When they were centralised,
1984 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001985 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301986
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987config STOP_MACHINE
1988 bool
1989 default y
1990 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1991 help
1992 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001993
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001994source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001995
1996config PREEMPT_NOTIFIERS
1997 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001998
Steffen Klassert16295be2010-01-06 19:47:10 +11001999config PADATA
2000 depends on SMP
2001 bool
2002
Andi Kleen754b7b62012-10-04 17:11:27 -07002003# Can be selected by architectures with broken toolchains
2004# that get confused by correct const<->read_only section
2005# mappings
2006config BROKEN_RODATA
2007 bool
2008
David Howells4520c6a2012-09-21 23:31:13 +01002009config ASN1
2010 tristate
2011 help
2012 Build a simple ASN.1 grammar compiler that produces a bytecode output
2013 that can be interpreted by the ASN.1 stream decoder and used to
2014 inform it as to what tags are to be expected in a stream and what
2015 functions to call on what tags.
2016
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002017source "kernel/Kconfig.locks"