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Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config 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"
397 help
398 If you say Y here, a user level program will be able to instruct the
399 kernel (via a special system call) to write process accounting
400 information to a file: whenever a process exits, information about
401 that process will be appended to the file by the kernel. The
402 information includes things such as creation time, owning user,
403 command name, memory usage, controlling terminal etc. (the complete
404 list is in the struct acct in <file:include/linux/acct.h>). It is
405 up to the user level program to do useful things with this
406 information. This is generally a good idea, so say Y.
407
408config BSD_PROCESS_ACCT_V3
409 bool "BSD Process Accounting version 3 file format"
410 depends on BSD_PROCESS_ACCT
411 default n
412 help
413 If you say Y here, the process accounting information is written
414 in a new file format that also logs the process IDs of each
415 process and it's parent. Note that this file format is incompatible
416 with previous v0/v1/v2 file formats, so you will need updated tools
417 for processing it. A preliminary version of these tools is available
418 at <http://www.gnu.org/software/acct/>.
419
420config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700421 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200422 depends on NET
423 default n
424 help
425 Export selected statistics for tasks/processes through the
426 generic netlink interface. Unlike BSD process accounting, the
427 statistics are available during the lifetime of tasks/processes as
428 responses to commands. Like BSD accounting, they are sent to user
429 space on task exit.
430
431 Say N if unsure.
432
433config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700434 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200435 depends on TASKSTATS
436 help
437 Collect information on time spent by a task waiting for system
438 resources like cpu, synchronous block I/O completion and swapping
439 in pages. Such statistics can help in setting a task's priorities
440 relative to other tasks for cpu, io, rss limits etc.
441
442 Say N if unsure.
443
444config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700445 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200446 depends on TASKSTATS
447 help
448 Collect extended task accounting data and send the data
449 to userland for processing over the taskstats interface.
450
451 Say N if unsure.
452
453config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700454 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200455 depends on TASK_XACCT
456 help
457 Collect information on the number of bytes of storage I/O which this
458 task has caused.
459
460 Say N if unsure.
461
462endmenu # "CPU/Task time and stats accounting"
463
Mike Travisc903ff82009-01-15 12:28:29 -0800464menu "RCU Subsystem"
465
466choice
467 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700468 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800469
Mike Travisc903ff82009-01-15 12:28:29 -0800470config TREE_RCU
471 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700472 depends on !PREEMPT && SMP
Steven Rostedt016a8d52013-05-28 17:32:53 -0400473 select IRQ_WORK
Mike Travisc903ff82009-01-15 12:28:29 -0800474 help
475 This option selects the RCU implementation that is
476 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700477 thousands of CPUs. It also scales down nicely to
478 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800479
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700480config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700481 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800482 depends on PREEMPT
James Hogan53614712013-07-25 15:34:25 +0100483 select IRQ_WORK
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700484 help
485 This option selects the RCU implementation that is
486 designed for very large SMP systems with hundreds or
487 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700488 is also required. It also scales down nicely to
489 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700490
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800491 Select this option if you are unsure.
492
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700493config TINY_RCU
494 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700495 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700496 help
497 This option selects the RCU implementation that is
498 designed for UP systems from which real-time response
499 is not required. This option greatly reduces the
500 memory footprint of RCU.
501
Mike Travisc903ff82009-01-15 12:28:29 -0800502endchoice
503
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700504config PREEMPT_RCU
Paul E. McKenney127781d2013-03-27 08:44:00 -0700505 def_bool TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700506 help
507 This option enables preemptible-RCU code that is common between
Paul E. McKenneyab74fdf2014-05-04 15:41:21 -0700508 TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700509
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700510config RCU_STALL_COMMON
511 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
512 help
513 This option enables RCU CPU stall code that is common between
514 the TINY and TREE variants of RCU. The purpose is to allow
515 the tiny variants to disable RCU CPU stall warnings, while
516 making these warnings mandatory for the tree variants.
517
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100518config CONTEXT_TRACKING
519 bool
520
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200521config RCU_USER_QS
522 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100523 depends on HAVE_CONTEXT_TRACKING && SMP
524 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200525 help
526 This option sets hooks on kernel / userspace boundaries and
527 puts RCU in extended quiescent state when the CPU runs in
528 userspace. It means that when a CPU runs in userspace, it is
529 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700530 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200531
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200532 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100533 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700534 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200535
536 If unsure say N
537
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100538config CONTEXT_TRACKING_FORCE
539 bool "Force context tracking"
540 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200541 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200542 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200543 The major pre-requirement for full dynticks to work is to
544 support the context tracking subsystem. But there are also
545 other dependencies to provide in order to make the full
546 dynticks working.
547
548 This option stands for testing when an arch implements the
549 context tracking backend but doesn't yet fullfill all the
550 requirements to make the full dynticks feature working.
551 Without the full dynticks, there is no way to test the support
552 for context tracking and the subsystems that rely on it: RCU
553 userspace extended quiescent state and tickless cputime
554 accounting. This option copes with the absence of the full
555 dynticks subsystem by forcing the context tracking on all
556 CPUs in the system.
557
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400558 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200559 architecture backend for the context tracking.
560
561 Say N otherwise, this option brings an overhead that you
562 don't want in production.
563
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200564
Mike Travisc903ff82009-01-15 12:28:29 -0800565config RCU_FANOUT
566 int "Tree-based hierarchical RCU fanout value"
567 range 2 64 if 64BIT
568 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700569 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800570 default 64 if 64BIT
571 default 32 if !64BIT
572 help
573 This option controls the fanout of hierarchical implementations
574 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700575 large numbers of CPUs. This value must be at least the fourth
576 root of NR_CPUS, which allows NR_CPUS to be insanely large.
577 The default value of RCU_FANOUT should be used for production
578 systems, but if you are stress-testing the RCU implementation
579 itself, small RCU_FANOUT values allow you to test large-system
580 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800581
582 Select a specific number if testing RCU itself.
583 Take the default if unsure.
584
Paul E. McKenney8932a632012-04-19 12:20:14 -0700585config RCU_FANOUT_LEAF
586 int "Tree-based hierarchical RCU leaf-level fanout value"
587 range 2 RCU_FANOUT if 64BIT
588 range 2 RCU_FANOUT if !64BIT
589 depends on TREE_RCU || TREE_PREEMPT_RCU
590 default 16
591 help
592 This option controls the leaf-level fanout of hierarchical
593 implementations of RCU, and allows trading off cache misses
594 against lock contention. Systems that synchronize their
595 scheduling-clock interrupts for energy-efficiency reasons will
596 want the default because the smaller leaf-level fanout keeps
597 lock contention levels acceptably low. Very large systems
598 (hundreds or thousands of CPUs) will instead want to set this
599 value to the maximum value possible in order to reduce the
600 number of cache misses incurred during RCU's grace-period
601 initialization. These systems tend to run CPU-bound, and thus
602 are not helped by synchronized interrupts, and thus tend to
603 skew them, which reduces lock contention enough that large
604 leaf-level fanouts work well.
605
606 Select a specific number if testing RCU itself.
607
608 Select the maximum permissible value for large systems.
609
610 Take the default if unsure.
611
Mike Travisc903ff82009-01-15 12:28:29 -0800612config RCU_FANOUT_EXACT
613 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700614 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800615 default n
616 help
617 This option forces use of the exact RCU_FANOUT value specified,
618 regardless of imbalances in the hierarchy. This is useful for
619 testing RCU itself, and might one day be useful on systems with
620 strong NUMA behavior.
621
622 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
623
624 Say N if unsure.
625
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800626config RCU_FAST_NO_HZ
627 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Frederic Weisbecker3451d022011-08-10 23:21:01 +0200628 depends on NO_HZ_COMMON && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800629 default n
630 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800631 This option permits CPUs to enter dynticks-idle state even if
632 they have RCU callbacks queued, and prevents RCU from waking
633 these CPUs up more than roughly once every four jiffies (by
634 default, you can adjust this using the rcutree.rcu_idle_gp_delay
635 parameter), thus improving energy efficiency. On the other
636 hand, this option increases the duration of RCU grace periods,
637 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800638
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800639 Say Y if energy efficiency is critically important, and you
640 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800641
642 Say N if you are unsure.
643
Mike Travisc903ff82009-01-15 12:28:29 -0800644config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700645 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800646 select DEBUG_FS
647 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700648 This option provides tracing for the TREE_RCU and
649 TREE_PREEMPT_RCU implementations, permitting Makefile to
650 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800651
Paul E. McKenney24278d12010-09-27 17:25:23 -0700652config RCU_BOOST
653 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800654 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700655 default n
656 help
657 This option boosts the priority of preempted RCU readers that
658 block the current preemptible RCU grace period for too long.
659 This option also prevents heavy loads from blocking RCU
660 callback invocation for all flavors of RCU.
661
662 Say Y here if you are working with real-time apps or heavy loads
663 Say N here if you are unsure.
664
665config RCU_BOOST_PRIO
666 int "Real-time priority to boost RCU readers to"
667 range 1 99
668 depends on RCU_BOOST
669 default 1
670 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700671 This option specifies the real-time priority to which long-term
672 preempted RCU readers are to be boosted. If you are working
673 with a real-time application that has one or more CPU-bound
674 threads running at a real-time priority level, you should set
675 RCU_BOOST_PRIO to a priority higher then the highest-priority
676 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
677 of 1 is appropriate in the common case, which is real-time
678 applications that do not have any CPU-bound threads.
679
680 Some real-time applications might not have a single real-time
681 thread that saturates a given CPU, but instead might have
682 multiple real-time threads that, taken together, fully utilize
683 that CPU. In this case, you should set RCU_BOOST_PRIO to
684 a priority higher than the lowest-priority thread that is
685 conspiring to prevent the CPU from running any non-real-time
686 tasks. For example, if one thread at priority 10 and another
687 thread at priority 5 are between themselves fully consuming
688 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
689 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700690
691 Specify the real-time priority, or take the default if unsure.
692
693config RCU_BOOST_DELAY
694 int "Milliseconds to delay boosting after RCU grace-period start"
695 range 0 3000
696 depends on RCU_BOOST
697 default 500
698 help
699 This option specifies the time to wait after the beginning of
700 a given grace period before priority-boosting preempted RCU
701 readers blocking that grace period. Note that any RCU reader
702 blocking an expedited RCU grace period is boosted immediately.
703
704 Accept the default if unsure.
705
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700706config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700707 bool "Offload RCU callback processing from boot-selected CPUs"
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700708 depends on TREE_RCU || TREE_PREEMPT_RCU
709 default n
710 help
711 Use this option to reduce OS jitter for aggressive HPC or
712 real-time workloads. It can also be used to offload RCU
713 callback invocation to energy-efficient CPUs in battery-powered
714 asymmetric multiprocessors.
715
716 This option offloads callback invocation from the set of
717 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800718 For each such CPU, a kthread ("rcuox/N") will be created to
719 invoke callbacks, where the "N" is the CPU being offloaded,
720 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
721 "s" for RCU-sched. Nothing prevents this kthread from running
722 on the specified CPUs, but (1) the kthreads may be preempted
723 between each callback, and (2) affinity or cgroups can be used
724 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700725
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800726 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700727 Say N here if you are unsure.
728
Paul E. McKenney911af502013-02-11 10:23:27 -0800729choice
730 prompt "Build-forced no-CBs CPUs"
731 default RCU_NOCB_CPU_NONE
732 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700733 This option allows no-CBs CPUs (whose RCU callbacks are invoked
734 from kthreads rather than from softirq context) to be specified
735 at build time. Additional no-CBs CPUs may be specified by
736 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800737
738config RCU_NOCB_CPU_NONE
739 bool "No build_forced no-CBs CPUs"
Paul E. McKenneyb58cc462014-07-02 10:13:24 -0700740 depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
Paul E. McKenney911af502013-02-11 10:23:27 -0800741 help
742 This option does not force any of the CPUs to be no-CBs CPUs.
743 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700744 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
745 kthreads whose names begin with "rcuo". All other CPUs will
746 invoke their own RCU callbacks in softirq context.
747
748 Select this option if you want to choose no-CBs CPUs at
749 boot time, for example, to allow testing of different no-CBs
750 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800751
752config RCU_NOCB_CPU_ZERO
753 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenneyb58cc462014-07-02 10:13:24 -0700754 depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
Paul E. McKenney911af502013-02-11 10:23:27 -0800755 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700756 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
757 callbacks are invoked by a per-CPU kthread whose name begins
758 with "rcuo". Additional CPUs may be designated as no-CBs
759 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
760 All other CPUs will invoke their own RCU callbacks in softirq
761 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800762
763 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700764 or energy-efficiency reasons, but the real reason it exists
765 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800766
767config RCU_NOCB_CPU_ALL
768 bool "All CPUs are build_forced no-CBs CPUs"
769 depends on RCU_NOCB_CPU
770 help
771 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700772 boot parameter will be ignored. All CPUs' RCU callbacks will
773 be executed in the context of per-CPU rcuo kthreads created for
774 this purpose. Assuming that the kthreads whose names start with
775 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
776 on the remaining CPUs, but might decrease memory locality during
777 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800778
779 Select this if all CPUs need to be no-CBs CPUs for real-time
780 or energy-efficiency reasons.
781
782endchoice
783
Mike Travisc903ff82009-01-15 12:28:29 -0800784endmenu # "RCU Subsystem"
785
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700786config BUILD_BIN2C
787 bool
788 default n
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700791 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700792 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 ---help---
794 This option enables the complete Linux kernel ".config" file
795 contents to be saved in the kernel. It provides documentation
796 of which kernel options are used in a running kernel or in an
797 on-disk kernel. This information can be extracted from the kernel
798 image file with the script scripts/extract-ikconfig and used as
799 input to rebuild the current kernel or to build another kernel.
800 It can also be extracted from a running kernel by reading
801 /proc/config.gz if enabled (below).
802
803config IKCONFIG_PROC
804 bool "Enable access to .config through /proc/config.gz"
805 depends on IKCONFIG && PROC_FS
806 ---help---
807 This option enables access to the kernel configuration file
808 through /proc/config.gz.
809
Alistair John Strachan794543a2007-05-08 00:31:15 -0700810config LOG_BUF_SHIFT
811 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
812 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700813 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700814 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700815 Select the minimal kernel log buffer size as a power of 2.
816 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
817 parameter, see below. Any higher size also might be forced
818 by "log_buf_len" boot parameter.
819
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700820 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700821 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700822 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700823 15 => 32 KB
824 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700825 13 => 8 KB
826 12 => 4 KB
827
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700828config LOG_CPU_MAX_BUF_SHIFT
829 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
830 range 0 21
831 default 12 if !BASE_SMALL
832 default 0 if BASE_SMALL
833 help
834 This option allows to increase the default ring buffer size
835 according to the number of CPUs. The value defines the contribution
836 of each CPU as a power of 2. The used space is typically only few
837 lines however it might be much more when problems are reported,
838 e.g. backtraces.
839
840 The increased size means that a new buffer has to be allocated and
841 the original static one is unused. It makes sense only on systems
842 with more CPUs. Therefore this value is used only when the sum of
843 contributions is greater than the half of the default kernel ring
844 buffer as defined by LOG_BUF_SHIFT. The default values are set
845 so that more than 64 CPUs are needed to trigger the allocation.
846
847 Also this option is ignored when "log_buf_len" kernel parameter is
848 used as it forces an exact (power of two) size of the ring buffer.
849
850 The number of possible CPUs is used for this computation ignoring
851 hotplugging making the compuation optimal for the the worst case
852 scenerio while allowing a simple algorithm to be used from bootup.
853
854 Examples shift values and their meaning:
855 17 => 128 KB for each CPU
856 16 => 64 KB for each CPU
857 15 => 32 KB for each CPU
858 14 => 16 KB for each CPU
859 13 => 8 KB for each CPU
860 12 => 4 KB for each CPU
861
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800862#
863# Architectures with an unreliable sched_clock() should select this:
864#
865config HAVE_UNSTABLE_SCHED_CLOCK
866 bool
867
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700868config GENERIC_SCHED_CLOCK
869 bool
870
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200871#
872# For architectures that want to enable the support for NUMA-affine scheduler
873# balancing logic:
874#
875config ARCH_SUPPORTS_NUMA_BALANCING
876 bool
877
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100878#
879# For architectures that know their GCC __int128 support is sound
880#
881config ARCH_SUPPORTS_INT128
882 bool
883
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200884# For architectures that (ab)use NUMA to represent different memory regions
885# all cpu-local but of different latencies, such as SuperH.
886#
887config ARCH_WANT_NUMA_VARIABLE_LOCALITY
888 bool
889
890#
891# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
892config ARCH_WANTS_PROT_NUMA_PROT_NONE
893 bool
894
895config ARCH_USES_NUMA_PROT_NONE
896 bool
897 default y
898 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
899 depends on NUMA_BALANCING
900
Mel Gorman1a687c22012-11-22 11:16:36 +0000901config NUMA_BALANCING_DEFAULT_ENABLED
902 bool "Automatically enable NUMA aware memory/task placement"
903 default y
904 depends on NUMA_BALANCING
905 help
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400906 If set, automatic NUMA balancing will be enabled if running on a NUMA
Mel Gorman1a687c22012-11-22 11:16:36 +0000907 machine.
908
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200909config NUMA_BALANCING
910 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200911 depends on ARCH_SUPPORTS_NUMA_BALANCING
912 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
913 depends on SMP && NUMA && MIGRATION
914 help
915 This option adds support for automatic NUMA aware memory/task placement.
916 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400917 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200918
919 This system will be inactive on UMA systems.
920
Li Zefan23964d22009-01-15 13:50:58 -0800921menuconfig CGROUPS
922 boolean "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500923 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700924 help
Li Zefan23964d22009-01-15 13:50:58 -0800925 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800926 use with process control subsystems such as Cpusets, CFS, memory
927 controls or device isolation.
928 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800929 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800930 - Documentation/cgroups/ (features for grouping, isolation
931 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700932
933 Say N if unsure.
934
Li Zefan23964d22009-01-15 13:50:58 -0800935if CGROUPS
936
Paul Menage006cb992007-10-18 23:39:43 -0700937config CGROUP_DEBUG
938 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700939 default n
Paul Menage006cb992007-10-18 23:39:43 -0700940 help
941 This option enables a simple cgroup subsystem that
942 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800943 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700944
Li Zefan23964d22009-01-15 13:50:58 -0800945 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700946
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700947config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800948 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800949 help
950 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700951 cgroup.
952
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700953config CGROUP_DEVICE
954 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700955 help
956 Provides a cgroup implementing whitelists for devices which
957 a process in the cgroup can mknod or open.
958
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959config CPUSETS
960 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700962 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 allow dynamically partitioning a system into sets of CPUs and
964 Memory Nodes and assigning tasks to run only within those sets.
965 This is primarily useful on large SMP or NUMA systems.
966
967 Say N if unsure.
968
Li Zefan23964d22009-01-15 13:50:58 -0800969config PROC_PID_CPUSET
970 bool "Include legacy /proc/<pid>/cpuset file"
971 depends on CPUSETS
972 default y
973
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100974config CGROUP_CPUACCT
975 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100976 help
977 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800978 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100979
Pavel Emelianove552b662008-02-07 00:13:49 -0800980config RESOURCE_COUNTERS
981 bool "Resource counters"
982 help
983 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800984 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800985
Andrew Mortonc255a452012-07-31 16:43:02 -0700986config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800987 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700988 depends on RESOURCE_COUNTERS
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
994 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700995 associated with each page of memory in the system. By this,
Sergey Dyaslyf60e2a92013-07-03 15:03:30 -0700996 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700997 usage tracking struct at boot. Total amount of this is printed out
998 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800999
1000 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -07001001 sure you need the memory resource controller. Even when you enable
1002 this, you can set "cgroup_disable=memory" at your boot option to
1003 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -08001004 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -08001005
Andrew Mortonc255a452012-07-31 16:43:02 -07001006config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001007 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001008 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001009 help
1010 Add swap management feature to memory resource controller. When you
1011 enable this, you can limit mem+swap usage per cgroup. In other words,
1012 when you disable this, memory resource controller has no cares to
1013 usage of swap...a process can exhaust all of the swap. This extension
1014 is useful when you want to avoid exhaustion swap but this itself
1015 adds more overheads and consumes memory for remembering information.
1016 Especially if you use 32bit system or small memory system, please
1017 be careful about enabling this. When memory resource controller
1018 is disabled by boot option, this will be automatically disabled and
1019 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001020 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001021 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1022 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001023config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001024 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001025 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001026 default y
1027 help
1028 Memory Resource Controller Swap Extension comes with its price in
1029 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001030 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001031 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001032 parameter should have this option unselected.
1033 For those who want to have the feature enabled by default should
1034 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001035 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001036config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001037 bool "Memory Resource Controller Kernel Memory accounting"
1038 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001039 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001040 help
1041 The Kernel Memory extension for Memory Resource Controller can limit
1042 the amount of memory used by kernel objects in the system. Those are
1043 fundamentally different from the entities handled by the standard
1044 Memory Controller, which are page-based, and can be swapped. Users of
1045 the kmem extension can use it to guarantee that no group of processes
1046 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001047
Vladimir Davydov2ee06462014-06-04 16:07:28 -07001048 WARNING: Current implementation lacks reclaim support. That means
1049 allocation attempts will fail when close to the limit even if there
1050 are plenty of kmem available for reclaim. That makes this option
1051 unusable in real life so DO NOT SELECT IT unless for development
1052 purposes.
1053
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001054config CGROUP_HUGETLB
1055 bool "HugeTLB Resource Controller for Control Groups"
Kees Cook19c92392012-10-02 11:19:29 -07001056 depends on RESOURCE_COUNTERS && HUGETLB_PAGE
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001057 default n
1058 help
1059 Provides a cgroup Resource Controller for HugeTLB pages.
1060 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1061 The limit is enforced during page fault. Since HugeTLB doesn't
1062 support page reclaim, enforcing the limit at page fault time implies
1063 that, the application will get SIGBUS signal if it tries to access
1064 HugeTLB pages beyond its limit. This requires the application to know
1065 beforehand how much HugeTLB pages it would require for its use. The
1066 control group is tracked in the third page lru pointer. This means
1067 that we cannot use the controller with huge page less than 3 pages.
1068
Stephane Eraniane5d13672011-02-14 11:20:01 +02001069config CGROUP_PERF
1070 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1071 depends on PERF_EVENTS && CGROUPS
1072 help
1073 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001074 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001075 designated cpu.
1076
1077 Say N if unsure.
1078
Dhaval Giani7c941432010-01-20 13:26:18 +01001079menuconfig CGROUP_SCHED
1080 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001081 default n
1082 help
1083 This feature lets CPU scheduler recognize task groups and control CPU
1084 bandwidth allocation to such task groups. It uses cgroups to group
1085 tasks.
1086
1087if CGROUP_SCHED
1088config FAIR_GROUP_SCHED
1089 bool "Group scheduling for SCHED_OTHER"
1090 depends on CGROUP_SCHED
1091 default CGROUP_SCHED
1092
Paul Turnerab84d312011-07-21 09:43:28 -07001093config CFS_BANDWIDTH
1094 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001095 depends on FAIR_GROUP_SCHED
1096 default n
1097 help
1098 This option allows users to define CPU bandwidth rates (limits) for
1099 tasks running within the fair group scheduler. Groups with no limit
1100 set are considered to be unconstrained and will run with no
1101 restriction.
1102 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1103
Dhaval Giani7c941432010-01-20 13:26:18 +01001104config RT_GROUP_SCHED
1105 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001106 depends on CGROUP_SCHED
1107 default n
1108 help
1109 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001110 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001111 schedule realtime tasks for non-root users until you allocate
1112 realtime bandwidth for them.
1113 See Documentation/scheduler/sched-rt-group.txt for more information.
1114
1115endif #CGROUP_SCHED
1116
Vivek Goyalafc24d42010-04-26 19:27:56 +02001117config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001118 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001119 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001120 default n
1121 ---help---
1122 Generic block IO controller cgroup interface. This is the common
1123 cgroup interface which should be used by various IO controlling
1124 policies.
1125
1126 Currently, CFQ IO scheduler uses it to recognize task groups and
1127 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001128 to such task groups. It is also used by bio throttling logic in
1129 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001130
1131 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001132 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001133 enabling proportional weight division of disk bandwidth in CFQ, set
1134 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001135 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001136
1137 See Documentation/cgroups/blkio-controller.txt for more information.
1138
1139config DEBUG_BLK_CGROUP
1140 bool "Enable Block IO controller debugging"
1141 depends on BLK_CGROUP
1142 default n
1143 ---help---
1144 Enable some debugging help. Currently it exports additional stat
1145 files in a cgroup which can be useful for debugging.
1146
Li Zefan23964d22009-01-15 13:50:58 -08001147endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001148
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001149config CHECKPOINT_RESTORE
1150 bool "Checkpoint/restore support" if EXPERT
1151 default n
1152 help
1153 Enables additional kernel features in a sake of checkpoint/restore.
1154 In particular it adds auxiliary prctl codes to setup process text,
1155 data and heap segment sizes, and a few additional /proc filesystem
1156 entries.
1157
1158 If unsure, say N here.
1159
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001160menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001161 bool "Namespaces support" if EXPERT
1162 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001163 help
1164 Provides the way to make tasks work with different objects using
1165 the same id. For example same IPC id may refer to different objects
1166 or same user id or pid may refer to different tasks when used in
1167 different namespaces.
1168
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001169if NAMESPACES
1170
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001171config UTS_NS
1172 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001173 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001174 help
1175 In this namespace tasks see different info provided with the
1176 uname() system call
1177
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001178config IPC_NS
1179 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001180 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001181 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001182 help
1183 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001184 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001185
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001186config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001187 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001188 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001189 help
1190 This allows containers, i.e. vservers, to use user namespaces
1191 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001192
1193 When user namespaces are enabled in the kernel it is
1194 recommended that the MEMCG and MEMCG_KMEM options also be
1195 enabled and that user-space use the memory control groups to
1196 limit the amount of memory a memory unprivileged users can
1197 use.
1198
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001199 If unsure, say N.
1200
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001201config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001202 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001203 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001204 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001205 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001206 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001207 pid namespaces. This is a building block of containers.
1208
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001209config NET_NS
1210 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001211 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001212 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001213 help
1214 Allow user space to create what appear to be multiple instances
1215 of the network stack.
1216
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001217endif # NAMESPACES
1218
Mike Galbraith5091faa2010-11-30 14:18:03 +01001219config SCHED_AUTOGROUP
1220 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001221 select CGROUPS
1222 select CGROUP_SCHED
1223 select FAIR_GROUP_SCHED
1224 help
1225 This option optimizes the scheduler for common desktop workloads by
1226 automatically creating and populating task groups. This separation
1227 of workloads isolates aggressive CPU burners (like build jobs) from
1228 desktop applications. Task group autogeneration is currently based
1229 upon task session.
1230
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001231config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001232 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001233 depends on SYSFS
1234 default n
1235 help
1236 This option adds code that switches the layout of the "block" class
1237 devices, to not show up in /sys/class/block/, but only in
1238 /sys/block/.
1239
1240 This switch is only active when the sysfs.deprecated=1 boot option is
1241 passed or the SYSFS_DEPRECATED_V2 option is set.
1242
1243 This option allows new kernels to run on old distributions and tools,
1244 which might get confused by /sys/class/block/. Since 2007/2008 all
1245 major distributions and tools handle this just fine.
1246
1247 Recent distributions and userspace tools after 2009/2010 depend on
1248 the existence of /sys/class/block/, and will not work with this
1249 option enabled.
1250
1251 Only if you are using a new kernel on an old distribution, you might
1252 need to say Y here.
1253
1254config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001255 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001256 default n
1257 depends on SYSFS
1258 depends on SYSFS_DEPRECATED
1259 help
1260 Enable deprecated sysfs by default.
1261
1262 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1263 option.
1264
1265 Only if you are using a new kernel on an old distribution, you might
1266 need to say Y here. Even then, odds are you would not need it
1267 enabled, you can always pass the boot option if absolutely necessary.
1268
1269config RELAY
1270 bool "Kernel->user space relay support (formerly relayfs)"
1271 help
1272 This option enables support for relay interface support in
1273 certain file systems (such as debugfs).
1274 It is designed to provide an efficient mechanism for tools and
1275 facilities to relay large amounts of data from kernel space to
1276 user space.
1277
1278 If unsure, say N.
1279
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001280config BLK_DEV_INITRD
1281 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1282 depends on BROKEN || !FRV
1283 help
1284 The initial RAM filesystem is a ramfs which is loaded by the
1285 boot loader (loadlin or lilo) and that is mounted as root
1286 before the normal boot procedure. It is typically used to
1287 load modules needed to mount the "real" root file system,
1288 etc. See <file:Documentation/initrd.txt> for details.
1289
1290 If RAM disk support (BLK_DEV_RAM) is also included, this
1291 also enables initial RAM disk (initrd) support and adds
1292 15 Kbytes (more on some other architectures) to the kernel size.
1293
1294 If unsure say Y.
1295
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001296if BLK_DEV_INITRD
1297
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001298source "usr/Kconfig"
1299
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001300endif
1301
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001302config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001303 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001304 help
1305 Enabling this option will pass "-Os" instead of "-O2" to gcc
1306 resulting in a smaller kernel.
1307
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001308 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001309
Randy Dunlap08470622006-09-30 23:28:13 -07001310config SYSCTL
1311 bool
1312
Randy Dunlapb943c462009-03-10 12:55:46 -07001313config ANON_INODES
1314 bool
1315
Mike Frysinger657a5202013-04-30 15:28:45 -07001316config HAVE_UID16
1317 bool
1318
1319config SYSCTL_EXCEPTION_TRACE
1320 bool
1321 help
1322 Enable support for /proc/sys/debug/exception-trace.
1323
1324config SYSCTL_ARCH_UNALIGN_NO_WARN
1325 bool
1326 help
1327 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1328 Allows arch to define/use @no_unaligned_warning to possibly warn
1329 about unaligned access emulation going on under the hood.
1330
1331config SYSCTL_ARCH_UNALIGN_ALLOW
1332 bool
1333 help
1334 Enable support for /proc/sys/kernel/unaligned-trap
1335 Allows arches to define/use @unaligned_enabled to runtime toggle
1336 the unaligned access emulation.
1337 see arch/parisc/kernel/unaligned.c for reference
1338
Mike Frysinger657a5202013-04-30 15:28:45 -07001339config HAVE_PCSPKR_PLATFORM
1340 bool
1341
David Rientjes6a108a12011-01-20 14:44:16 -08001342menuconfig EXPERT
1343 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001344 # Unhide debug options, to make the on-by-default options visible
1345 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 help
1347 This option allows certain base kernel options and settings
1348 to be disabled or tweaked. This is for specialized
1349 environments which can tolerate a "non-standard" kernel.
1350 Only use this if you really know what you are doing.
1351
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001352config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001353 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001354 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001355 default y
1356 help
1357 This enables the legacy 16-bit UID syscall wrappers.
1358
Fabian Frederickf6187762014-06-04 16:11:12 -07001359config SGETMASK_SYSCALL
1360 bool "sgetmask/ssetmask syscalls support" if EXPERT
1361 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1362 ---help---
1363 sys_sgetmask and sys_ssetmask are obsolete system calls
1364 no longer supported in libc but still enabled by default in some
1365 architectures.
1366
1367 If unsure, leave the default option here.
1368
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001369config SYSFS_SYSCALL
1370 bool "Sysfs syscall support" if EXPERT
1371 default y
1372 ---help---
1373 sys_sysfs is an obsolete system call no longer supported in libc.
1374 Note that disabling this option is more secure but might break
1375 compatibility with some systems.
1376
1377 If unsure say Y here.
1378
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001379config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001380 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001381 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001382 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001383 select SYSCTL
1384 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001385 sys_sysctl uses binary paths that have been found challenging
1386 to properly maintain and use. The interface in /proc/sys
1387 using paths with ascii names is now the primary path to this
1388 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001389
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001390 Almost nothing using the binary sysctl interface so if you are
1391 trying to save some space it is probably safe to disable this,
1392 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001393
WANG Congc736de62011-11-02 13:39:25 -07001394 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001395
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001397 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 default y
1399 help
1400 Say Y here to let the kernel print out symbolic crash information and
1401 symbolic stack backtraces. This increases the size of the kernel
1402 somewhat, as all symbols have to be loaded into the kernel image.
1403
1404config KALLSYMS_ALL
1405 bool "Include all symbols in kallsyms"
1406 depends on DEBUG_KERNEL && KALLSYMS
1407 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001408 Normally kallsyms only contains the symbols of functions for nicer
1409 OOPS messages and backtraces (i.e., symbols from the text and inittext
1410 sections). This is sufficient for most cases. And only in very rare
1411 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1412 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001414 This option makes sure that all symbols are loaded into the kernel
1415 image (i.e., symbols from all sections) in cost of increased kernel
1416 size (depending on the kernel configuration, it may be 300KiB or
1417 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001419 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001420
1421config PRINTK
1422 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001423 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001424 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001425 help
1426 This option enables normal printk support. Removing it
1427 eliminates most of the message strings from the kernel image
1428 and makes the kernel more or less silent. As this makes it
1429 very difficult to diagnose system problems, saying N here is
1430 strongly discouraged.
1431
Matt Mackallc8538a72005-05-01 08:59:01 -07001432config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001433 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001434 default y
1435 help
1436 Disabling this option eliminates support for BUG and WARN, reducing
1437 the size of your kernel image and potentially quietly ignoring
1438 numerous fatal conditions. You should only consider disabling this
1439 option for embedded systems with no facilities for reporting errors.
1440 Just say Y.
1441
Matt Mackall708e9a72006-01-08 01:05:25 -08001442config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001443 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001444 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001445 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001446 help
1447 Enable support for generating core dumps. Disabling saves about 4k.
1448
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001449
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001450config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001451 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001452 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001453 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001454 default y
1455 help
1456 This option allows to disable the internal PC-Speaker
1457 support, saving some memory.
1458
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459config BASE_FULL
1460 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001461 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 help
1463 Disabling this option reduces the size of miscellaneous core
1464 kernel data structures. This saves memory on small machines,
1465 but may reduce performance.
1466
1467config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001468 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001470 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 help
1472 Disabling this option will cause the kernel to be built without
1473 support for "fast userspace mutexes". The resulting kernel may not
1474 run glibc-based applications correctly.
1475
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001476config HAVE_FUTEX_CMPXCHG
1477 bool
1478 help
1479 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1480 is implemented and always working. This removes a couple of runtime
1481 checks.
1482
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001484 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001486 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 help
1488 Disabling this option will cause the kernel to be built without
1489 support for epoll family of system calls.
1490
Davide Libenzifba2afa2007-05-10 22:23:13 -07001491config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001492 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001493 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001494 default y
1495 help
1496 Enable the signalfd() system call that allows to receive signals
1497 on a file descriptor.
1498
1499 If unsure, say Y.
1500
Davide Libenzib215e282007-05-10 22:23:16 -07001501config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001502 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001503 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001504 default y
1505 help
1506 Enable the timerfd() system call that allows to receive timer
1507 events on a file descriptor.
1508
1509 If unsure, say Y.
1510
Davide Libenzie1ad7462007-05-10 22:23:19 -07001511config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001512 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001513 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001514 default y
1515 help
1516 Enable the eventfd() system call that allows to receive both
1517 kernel notification (ie. KAIO) or userspace notifications.
1518
1519 If unsure, say Y.
1520
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001522 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 default y
1524 depends on MMU
1525 help
1526 The shmem is an internal filesystem used to manage shared memory.
1527 It is backed by swap and manages resource limits. It is also exported
1528 to userspace as tmpfs if TMPFS is enabled. Disabling this
1529 option replaces shmem and tmpfs with the much simpler ramfs code,
1530 which may be appropriate on small systems without swap.
1531
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001532config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001533 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001534 default y
1535 help
1536 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001537 by some high performance threaded applications. Disabling
1538 this option saves about 7k.
1539
1540config PCI_QUIRKS
1541 default y
1542 bool "Enable PCI quirk workarounds" if EXPERT
1543 depends on PCI
1544 help
1545 This enables workarounds for various PCI chipset
1546 bugs/quirks. Disable this only if your target machine is
1547 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001548
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001549config EMBEDDED
1550 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001551 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001552 select EXPERT
1553 help
1554 This option should be enabled if compiling the kernel for
1555 an embedded system so certain expert options are available
1556 for configuration.
1557
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001558config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001559 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001560 help
1561 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001562
Peter Zijlstra906010b2009-09-21 16:08:49 +02001563config PERF_USE_VMALLOC
1564 bool
1565 help
1566 See tools/perf/design.txt for details
1567
Ingo Molnar57c0c152009-09-21 12:20:38 +02001568menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001569
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001570config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001571 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001572 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001573 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001574 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001575 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001576 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001577 Enable kernel support for various performance events provided
1578 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001579
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001580 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001581 use of generic tracepoints.
1582
1583 Most modern CPUs support performance events via performance
1584 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001585 types of hw events: such as instructions executed, cachemisses
1586 suffered, or branches mis-predicted - without slowing down the
1587 kernel or applications. These registers can also trigger interrupts
1588 when a threshold number of events have passed - and can thus be
1589 used to profile the code that runs on that CPU.
1590
Ingo Molnar57c0c152009-09-21 12:20:38 +02001591 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001592 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001593 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001594 provides per task and per CPU counters, and it provides event
1595 capabilities on top of those.
1596
1597 Say Y if unsure.
1598
Peter Zijlstra906010b2009-09-21 16:08:49 +02001599config DEBUG_PERF_USE_VMALLOC
1600 default n
1601 bool "Debug: use vmalloc to back perf mmap() buffers"
1602 depends on PERF_EVENTS && DEBUG_KERNEL
1603 select PERF_USE_VMALLOC
1604 help
1605 Use vmalloc memory to back perf mmap() buffers.
1606
1607 Mostly useful for debugging the vmalloc code on platforms
1608 that don't require it.
1609
1610 Say N if unsure.
1611
Thomas Gleixner0793a612008-12-04 20:12:29 +01001612endmenu
1613
Christoph Lameterf8891e52006-06-30 01:55:45 -07001614config VM_EVENT_COUNTERS
1615 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001616 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001617 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001618 VM event counters are needed for event counts to be shown.
1619 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001620 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001621 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001622
Christoph Lameter41ecc552007-05-09 02:32:44 -07001623config SLUB_DEBUG
1624 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001625 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001626 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001627 help
1628 SLUB has extensive debug support features. Disabling these can
1629 result in significant savings in code size. This also disables
1630 SLUB sysfs support. /sys/slab will not exist and there will be
1631 no support for cache validation etc.
1632
Randy Dunlapb943c462009-03-10 12:55:46 -07001633config COMPAT_BRK
1634 bool "Disable heap randomization"
1635 default y
1636 help
1637 Randomizing heap placement makes heap exploits harder, but it
1638 also breaks ancient binaries (including anything libc5 based).
1639 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001640 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001641 /proc/sys/kernel/randomize_va_space to 2.
1642
1643 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1644
Christoph Lameter81819f02007-05-06 14:49:36 -07001645choice
1646 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001647 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001648 help
1649 This option allows to select a slab allocator.
1650
1651config SLAB
1652 bool "SLAB"
1653 help
1654 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001655 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001656 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001657
1658config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001659 bool "SLUB (Unqueued Allocator)"
1660 help
1661 SLUB is a slab allocator that minimizes cache line usage
1662 instead of managing queues of cached objects (SLAB approach).
1663 Per cpu caching is realized using slabs of objects instead
1664 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001665 and has enhanced diagnostics. SLUB is the default choice for
1666 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001667
1668config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001669 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001670 bool "SLOB (Simple Allocator)"
1671 help
Matt Mackall37291452008-02-04 22:29:38 -08001672 SLOB replaces the stock allocator with a drastically simpler
1673 allocator. SLOB is generally more space efficient but
1674 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001675
1676endchoice
1677
Joonsoo Kim345c9052013-06-19 14:05:52 +09001678config SLUB_CPU_PARTIAL
1679 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001680 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001681 bool "SLUB per cpu partial cache"
1682 help
1683 Per cpu partial caches accellerate objects allocation and freeing
1684 that is local to a processor at the price of more indeterminism
1685 in the latency of the free. On overflow these caches will be cleared
1686 which requires the taking of locks that may cause latency spikes.
1687 Typically one would choose no for a realtime system.
1688
Jie Zhangea637632009-12-14 18:00:02 -08001689config MMAP_ALLOW_UNINITIALIZED
1690 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001691 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001692 default n
1693 help
1694 Normally, and according to the Linux spec, anonymous memory obtained
1695 from mmap() has it's contents cleared before it is passed to
1696 userspace. Enabling this config option allows you to request that
1697 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1698 providing a huge performance boost. If this option is not enabled,
1699 then the flag will be ignored.
1700
1701 This is taken advantage of by uClibc's malloc(), and also by
1702 ELF-FDPIC binfmt's brk and stack allocator.
1703
1704 Because of the obvious security issues, this option should only be
1705 enabled on embedded devices where you control what is run in
1706 userspace. Since that isn't generally a problem on no-MMU systems,
1707 it is normally safe to say Y here.
1708
1709 See Documentation/nommu-mmap.txt for more information.
1710
Peter Foley82c04ff2014-04-18 15:07:11 -07001711config SYSTEM_TRUSTED_KEYRING
1712 bool "Provide system-wide ring of trusted keys"
1713 depends on KEYS
1714 help
1715 Provide a system keyring to which trusted keys can be added. Keys in
1716 the keyring are considered to be trusted. Keys may be added at will
1717 by the kernel from compiled-in data and from hardware key stores, but
1718 userspace may only add extra keys if those keys can be verified by
1719 keys already in the keyring.
1720
1721 Keys in this keyring are used by module signature checking.
1722
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001723config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001724 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001725 help
1726 Say Y here to enable the extended profiling support mechanisms used
1727 by profilers such as OProfile.
1728
Ingo Molnar5f87f112008-07-23 14:15:22 +02001729#
1730# Place an empty function call at each tracepoint site. Can be
1731# dynamically changed for a probe function.
1732#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001733config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001734 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001735
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001736source "arch/Kconfig"
1737
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738endmenu # General setup
1739
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001740config HAVE_GENERIC_DMA_COHERENT
1741 bool
1742 default n
1743
Linus Torvalds158a9622008-01-02 13:04:48 -08001744config SLABINFO
1745 bool
1746 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001747 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001748 default y
1749
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001750config RT_MUTEXES
1751 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001752
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753config BASE_SMALL
1754 int
1755 default 0 if BASE_FULL
1756 default 1 if !BASE_FULL
1757
Jan Engelhardt66da5732007-07-15 23:39:29 -07001758menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001760 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 help
1762 Kernel modules are small pieces of compiled code which can
1763 be inserted in the running kernel, rather than being
1764 permanently built into the kernel. You use the "modprobe"
1765 tool to add (and sometimes remove) them. If you say Y here,
1766 many parts of the kernel can be built as modules (by
1767 answering M instead of Y where indicated): this is most
1768 useful for infrequently used options which are not required
1769 for booting. For more information, see the man pages for
1770 modprobe, lsmod, modinfo, insmod and rmmod.
1771
1772 If you say Y here, you will need to run "make
1773 modules_install" to put the modules under /lib/modules/
1774 where modprobe can find them (you may need to be root to do
1775 this).
1776
1777 If unsure, say Y.
1778
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001779if MODULES
1780
Linus Torvalds826e4502008-05-04 17:04:16 -07001781config MODULE_FORCE_LOAD
1782 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001783 default n
1784 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001785 Allow loading of modules without version information (ie. modprobe
1786 --force). Forced module loading sets the 'F' (forced) taint flag and
1787 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001788
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789config MODULE_UNLOAD
1790 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 help
1792 Without this option you will not be able to unload any
1793 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001794 anyway), which makes your kernel smaller, faster
1795 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796
1797config MODULE_FORCE_UNLOAD
1798 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001799 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800 help
1801 This option allows you to force a module to unload, even if the
1802 kernel believes it is unsafe: the kernel will remove the module
1803 without waiting for anyone to stop using it (using the -f option to
1804 rmmod). This is mainly for kernel developers and desperate users.
1805 If unsure, say N.
1806
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001808 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 help
1810 Usually, you have to use modules compiled with your kernel.
1811 Saying Y here makes it sometimes possible to use modules
1812 compiled for different kernels, by adding enough information
1813 to the modules to (hopefully) spot any changes which would
1814 make them incompatible with the kernel you are running. If
1815 unsure, say N.
1816
1817config MODULE_SRCVERSION_ALL
1818 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 help
1820 Modules which contain a MODULE_VERSION get an extra "srcversion"
1821 field inserted into their modinfo section, which contains a
1822 sum of the source files which made it. This helps maintainers
1823 see exactly which source was used to build a module (since
1824 others sometimes change the module source without updating
1825 the version). With this option, such a "srcversion" field
1826 will be created for all modules. If unsure, say N.
1827
Rusty Russell106a4ee2012-09-26 10:09:40 +01001828config MODULE_SIG
1829 bool "Module signature verification"
1830 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001831 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001832 select KEYS
1833 select CRYPTO
1834 select ASYMMETRIC_KEY_TYPE
1835 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1836 select PUBLIC_KEY_ALGO_RSA
1837 select ASN1
1838 select OID_REGISTRY
1839 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001840 help
1841 Check modules for valid signatures upon load: the signature
1842 is simply appended to the module. For more information see
1843 Documentation/module-signing.txt.
1844
David Howellsea0b6dc2012-09-26 10:09:50 +01001845 !!!WARNING!!! If you enable this option, you MUST make sure that the
1846 module DOES NOT get stripped after being signed. This includes the
1847 debuginfo strip done by some packagers (such as rpmbuild) and
1848 inclusion into an initramfs that wants the module size reduced.
1849
Rusty Russell106a4ee2012-09-26 10:09:40 +01001850config MODULE_SIG_FORCE
1851 bool "Require modules to be validly signed"
1852 depends on MODULE_SIG
1853 help
1854 Reject unsigned modules or signed modules for which we don't have a
1855 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001856
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301857config MODULE_SIG_ALL
1858 bool "Automatically sign all modules"
1859 default y
1860 depends on MODULE_SIG
1861 help
1862 Sign all modules during make modules_install. Without this option,
1863 modules must be signed manually, using the scripts/sign-file tool.
1864
1865comment "Do not forget to sign required modules with scripts/sign-file"
1866 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1867
David Howellsea0b6dc2012-09-26 10:09:50 +01001868choice
1869 prompt "Which hash algorithm should modules be signed with?"
1870 depends on MODULE_SIG
1871 help
1872 This determines which sort of hashing algorithm will be used during
1873 signature generation. This algorithm _must_ be built into the kernel
1874 directly so that signature verification can take place. It is not
1875 possible to load a signed module containing the algorithm to check
1876 the signature on that module.
1877
1878config MODULE_SIG_SHA1
1879 bool "Sign modules with SHA-1"
1880 select CRYPTO_SHA1
1881
1882config MODULE_SIG_SHA224
1883 bool "Sign modules with SHA-224"
1884 select CRYPTO_SHA256
1885
1886config MODULE_SIG_SHA256
1887 bool "Sign modules with SHA-256"
1888 select CRYPTO_SHA256
1889
1890config MODULE_SIG_SHA384
1891 bool "Sign modules with SHA-384"
1892 select CRYPTO_SHA512
1893
1894config MODULE_SIG_SHA512
1895 bool "Sign modules with SHA-512"
1896 select CRYPTO_SHA512
1897
1898endchoice
1899
Michal Marek22753672013-01-25 13:41:00 +10301900config MODULE_SIG_HASH
1901 string
1902 depends on MODULE_SIG
1903 default "sha1" if MODULE_SIG_SHA1
1904 default "sha224" if MODULE_SIG_SHA224
1905 default "sha256" if MODULE_SIG_SHA256
1906 default "sha384" if MODULE_SIG_SHA384
1907 default "sha512" if MODULE_SIG_SHA512
1908
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001909endif # MODULES
1910
Rusty Russell98a79d62008-12-13 21:19:41 +10301911config INIT_ALL_POSSIBLE
1912 bool
1913 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301914 Back when each arch used to define their own cpu_online_mask and
1915 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301916 with all 1s, and others with all 0s. When they were centralised,
1917 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001918 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301919
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920config STOP_MACHINE
1921 bool
1922 default y
1923 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1924 help
1925 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001926
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001927source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001928
1929config PREEMPT_NOTIFIERS
1930 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001931
Steffen Klassert16295be2010-01-06 19:47:10 +11001932config PADATA
1933 depends on SMP
1934 bool
1935
Andi Kleen754b7b62012-10-04 17:11:27 -07001936# Can be selected by architectures with broken toolchains
1937# that get confused by correct const<->read_only section
1938# mappings
1939config BROKEN_RODATA
1940 bool
1941
David Howells4520c6a2012-09-21 23:31:13 +01001942config ASN1
1943 tristate
1944 help
1945 Build a simple ASN.1 grammar compiler that produces a bytecode output
1946 that can be interpreted by the ASN.1 stream decoder and used to
1947 inform it as to what tags are to be expected in a stream and what
1948 functions to call on what tags.
1949
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001950source "kernel/Kconfig.locks"