blob: f5dbc6d4261bcb47e7d7dccfa6385f649ecefa0a [file] [log] [blame]
Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config IRQ_WORK
24 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +080025
David Daney1dbdc6f2012-04-19 14:59:57 -070026config BUILDTIME_EXTABLE_SORT
27 bool
28
Al Boldiff0cfc62007-07-31 00:39:23 -070029menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031config BROKEN
32 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34config BROKEN_ON_SMP
35 bool
36 depends on BROKEN || !SMP
37 default y
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config INIT_ENV_ARG_LIMIT
40 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070041 default 32 if !UML
42 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080044 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Roland McGrath84336462009-12-21 16:24:06 -080048config CROSS_COMPILE
49 string "Cross-compiler tool prefix"
50 help
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically.
55
Jiri Slaby4bb16672013-05-22 10:56:24 +020056config COMPILE_TEST
57 bool "Compile also drivers which will not load"
58 default n
59 help
60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them.
65
66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed.
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070config LOCALVERSION
71 string "Local version - append to kernel release"
72 help
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
79
Ryan Andersonaaebf432005-07-31 04:57:49 -040080config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
82 default y
83 help
84 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020085 release tree by looking for git tags that belong to the current
86 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040087
88 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020089 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040090 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020091 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -040092
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020093 (The actual string used here is the first eight characters produced
94 by running the command:
95
96 $ git rev-parse --verify HEAD
97
98 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -040099
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800100config HAVE_KERNEL_GZIP
101 bool
102
103config HAVE_KERNEL_BZIP2
104 bool
105
106config HAVE_KERNEL_LZMA
107 bool
108
Lasse Collin3ebe1242011-01-12 17:01:23 -0800109config HAVE_KERNEL_XZ
110 bool
111
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800112config HAVE_KERNEL_LZO
113 bool
114
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700115config HAVE_KERNEL_LZ4
116 bool
117
Alain Knaff30d65db2009-01-04 22:46:17 +0100118choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800119 prompt "Kernel compression mode"
120 default KERNEL_GZIP
H. Peter Anvin2d3c6272013-11-14 21:43:47 -0800121 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800122 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot.
128
129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig)
133
134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram
136 size matters less.
137
138 If in doubt, select 'gzip'
139
140config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800141 bool "Gzip"
142 depends on HAVE_KERNEL_GZIP
143 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100146
147config KERNEL_BZIP2
148 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800149 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100150 help
151 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700152 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100156
157config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800158 bool "LZMA"
159 depends on HAVE_KERNEL_LZMA
160 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
Lasse Collin3ebe1242011-01-12 17:01:23 -0800165config KERNEL_XZ
166 bool "XZ"
167 depends on HAVE_KERNEL_XZ
168 help
169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA.
175
176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow.
179
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800180config KERNEL_LZO
181 bool "LZO"
182 depends on HAVE_KERNEL_LZO
183 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700184 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200185 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800186 (both compression and decompression) is the fastest.
187
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700188config KERNEL_LZ4
189 bool "LZ4"
190 depends on HAVE_KERNEL_LZ4
191 help
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>.
195
196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is
198 faster than LZO.
199
Alain Knaff30d65db2009-01-04 22:46:17 +0100200endchoice
201
Josh Triplettbd5dc172011-06-15 15:08:28 -0700202config DEFAULT_HOSTNAME
203 string "Default hostname"
204 default "(none)"
205 help
206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration.
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211config SWAP
212 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200213 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 default y
215 help
216 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100217 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y.
220
221config SYSVIPC
222 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 ---help---
224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here.
231
232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>.
235
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800236config SYSVIPC_SYSCTL
237 bool
238 depends on SYSVIPC
239 depends on SYSCTL
240 default y
241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242config POSIX_MQUEUE
243 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700244 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 ---help---
246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200250 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues.
255
256 If unsure, say Y.
257
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700258config POSIX_MQUEUE_SYSCTL
259 bool
260 depends on POSIX_MQUEUE
261 depends on SYSCTL
262 default y
263
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700264config CROSS_MEMORY_ATTACH
265 bool "Enable process_vm_readv/writev syscalls"
266 depends on MMU
267 default y
268 help
269 Enabling this option adds the system calls process_vm_readv and
270 process_vm_writev which allow a process with the correct privileges
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700271 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700272 See the man page for more details.
273
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530274config FHANDLE
275 bool "open by fhandle syscalls"
276 select EXPORTFS
277 help
278 If you say Y here, a user level program will be able to map
279 file names to handle and then later use the handle for
280 different file system operations. This is useful in implementing
281 userspace file servers, which now track files using handles instead
282 of names. The handle would remain the same even if file names
283 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
284 syscalls.
285
Josh Triplett69369a72014-04-03 14:48:27 -0700286config USELIB
287 bool "uselib syscall"
288 default y
289 help
290 This option enables the uselib syscall, a system call used in the
291 dynamic linker from libc5 and earlier. glibc does not use this
292 system call. If you intend to run programs built on libc5 or
293 earlier, you may need to enable this syscall. Current systems
294 running glibc can safely disable this.
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296config AUDIT
297 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100298 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 help
300 Enable auditing infrastructure that can be used with another
301 kernel subsystem, such as SELinux (which requires this for
302 logging of avc messages output). Does not do system-call
303 auditing without CONFIG_AUDITSYSCALL.
304
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900305config HAVE_ARCH_AUDITSYSCALL
306 bool
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308config AUDITSYSCALL
309 bool "Enable system-call auditing support"
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 default y if SECURITY_SELINUX
312 help
313 Enable low-overhead system-call auditing infrastructure that
314 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500315 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Eric Paris939a67f2009-12-17 20:12:06 -0500317config AUDIT_WATCH
318 def_bool y
319 depends on AUDITSYSCALL
320 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Al Viro74c3cbe2007-07-22 08:04:18 -0400322config AUDIT_TREE
323 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400324 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500325 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400326
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000327source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200328source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000329
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200330menu "CPU/Task time and stats accounting"
331
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200332config VIRT_CPU_ACCOUNTING
333 bool
334
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200335choice
336 prompt "Cputime accounting"
337 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100338 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200339
340# Kind of a stub config for the pure tick based cputime accounting
341config TICK_CPU_ACCOUNTING
342 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200343 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200344 help
345 This is the basic tick based cputime accounting that maintains
346 statistics about user, system and idle time spent on per jiffies
347 granularity.
348
349 If unsure, say Y.
350
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200351config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200352 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200353 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200354 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200355 help
356 Select this option to enable more accurate task and CPU time
357 accounting. This is done by reading a CPU counter on each
358 kernel entry and exit and on transitions within the kernel
359 between system, softirq and hardirq state, so there is a
360 small performance impact. In the case of s390 or IBM POWER > 5,
361 this also enables accounting of stolen time on logically-partitioned
362 systems.
363
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200364config VIRT_CPU_ACCOUNTING_GEN
365 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700366 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700367 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200368 select VIRT_CPU_ACCOUNTING
369 select CONTEXT_TRACKING
370 help
371 Select this option to enable task and CPU time accounting on full
372 dynticks systems. This accounting is implemented by watching every
373 kernel-user boundaries using the context tracking subsystem.
374 The accounting is thus performed at the expense of some significant
375 overhead.
376
377 For now this is only useful if you are working on the full
378 dynticks subsystem development.
379
380 If unsure, say N.
381
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200382config IRQ_TIME_ACCOUNTING
383 bool "Fine granularity task level IRQ time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200384 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200385 help
386 Select this option to enable fine granularity task irq time
387 accounting. This is done by reading a timestamp on each
388 transitions between softirq and hardirq state, so there can be a
389 small performance impact.
390
391 If in doubt, say N here.
392
393endchoice
394
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200395config BSD_PROCESS_ACCT
396 bool "BSD Process Accounting"
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
Mike Travisc903ff82009-01-15 12:28:29 -0800473 help
474 This option selects the RCU implementation that is
475 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700476 thousands of CPUs. It also scales down nicely to
477 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800478
Pranith Kumar28f65692014-09-22 14:00:48 -0400479config PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700480 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800481 depends on PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700482 help
483 This option selects the RCU implementation that is
484 designed for very large SMP systems with hundreds or
485 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700486 is also required. It also scales down nicely to
487 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700488
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800489 Select this option if you are unsure.
490
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700491config TINY_RCU
492 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700493 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700494 help
495 This option selects the RCU implementation that is
496 designed for UP systems from which real-time response
497 is not required. This option greatly reduces the
498 memory footprint of RCU.
499
Mike Travisc903ff82009-01-15 12:28:29 -0800500endchoice
501
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500502config SRCU
503 bool
504 help
505 This option selects the sleepable version of RCU. This version
506 permits arbitrary sleeping or blocking within RCU read-side critical
507 sections.
508
Paul E. McKenney8315f422014-06-27 13:42:20 -0700509config TASKS_RCU
510 bool "Task_based RCU implementation using voluntary context switch"
511 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500512 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700513 help
514 This option enables a task-based RCU implementation that uses
515 only voluntary context switch (not preemption!), idle, and
516 user-mode execution as quiescent states.
517
518 If unsure, say N.
519
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700520config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400521 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700522 help
523 This option enables RCU CPU stall code that is common between
524 the TINY and TREE variants of RCU. The purpose is to allow
525 the tiny variants to disable RCU CPU stall warnings, while
526 making these warnings mandatory for the tree variants.
527
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100528config CONTEXT_TRACKING
529 bool
530
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200531config RCU_USER_QS
532 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100533 depends on HAVE_CONTEXT_TRACKING && SMP
534 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200535 help
536 This option sets hooks on kernel / userspace boundaries and
537 puts RCU in extended quiescent state when the CPU runs in
538 userspace. It means that when a CPU runs in userspace, it is
539 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700540 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200541
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200542 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100543 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700544 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200545
546 If unsure say N
547
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100548config CONTEXT_TRACKING_FORCE
549 bool "Force context tracking"
550 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200551 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200552 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200553 The major pre-requirement for full dynticks to work is to
554 support the context tracking subsystem. But there are also
555 other dependencies to provide in order to make the full
556 dynticks working.
557
558 This option stands for testing when an arch implements the
559 context tracking backend but doesn't yet fullfill all the
560 requirements to make the full dynticks feature working.
561 Without the full dynticks, there is no way to test the support
562 for context tracking and the subsystems that rely on it: RCU
563 userspace extended quiescent state and tickless cputime
564 accounting. This option copes with the absence of the full
565 dynticks subsystem by forcing the context tracking on all
566 CPUs in the system.
567
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400568 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200569 architecture backend for the context tracking.
570
571 Say N otherwise, this option brings an overhead that you
572 don't want in production.
573
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200574
Mike Travisc903ff82009-01-15 12:28:29 -0800575config RCU_FANOUT
576 int "Tree-based hierarchical RCU fanout value"
577 range 2 64 if 64BIT
578 range 2 32 if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400579 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800580 default 64 if 64BIT
581 default 32 if !64BIT
582 help
583 This option controls the fanout of hierarchical implementations
584 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700585 large numbers of CPUs. This value must be at least the fourth
586 root of NR_CPUS, which allows NR_CPUS to be insanely large.
587 The default value of RCU_FANOUT should be used for production
588 systems, but if you are stress-testing the RCU implementation
589 itself, small RCU_FANOUT values allow you to test large-system
590 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800591
592 Select a specific number if testing RCU itself.
593 Take the default if unsure.
594
Paul E. McKenney8932a632012-04-19 12:20:14 -0700595config RCU_FANOUT_LEAF
596 int "Tree-based hierarchical RCU leaf-level fanout value"
597 range 2 RCU_FANOUT if 64BIT
598 range 2 RCU_FANOUT if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400599 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney8932a632012-04-19 12:20:14 -0700600 default 16
601 help
602 This option controls the leaf-level fanout of hierarchical
603 implementations of RCU, and allows trading off cache misses
604 against lock contention. Systems that synchronize their
605 scheduling-clock interrupts for energy-efficiency reasons will
606 want the default because the smaller leaf-level fanout keeps
607 lock contention levels acceptably low. Very large systems
608 (hundreds or thousands of CPUs) will instead want to set this
609 value to the maximum value possible in order to reduce the
610 number of cache misses incurred during RCU's grace-period
611 initialization. These systems tend to run CPU-bound, and thus
612 are not helped by synchronized interrupts, and thus tend to
613 skew them, which reduces lock contention enough that large
614 leaf-level fanouts work well.
615
616 Select a specific number if testing RCU itself.
617
618 Select the maximum permissible value for large systems.
619
620 Take the default if unsure.
621
Mike Travisc903ff82009-01-15 12:28:29 -0800622config RCU_FANOUT_EXACT
623 bool "Disable tree-based hierarchical RCU auto-balancing"
Pranith Kumar28f65692014-09-22 14:00:48 -0400624 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800625 default n
626 help
627 This option forces use of the exact RCU_FANOUT value specified,
628 regardless of imbalances in the hierarchy. This is useful for
629 testing RCU itself, and might one day be useful on systems with
630 strong NUMA behavior.
631
632 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
633
634 Say N if unsure.
635
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800636config RCU_FAST_NO_HZ
637 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Frederic Weisbecker3451d022011-08-10 23:21:01 +0200638 depends on NO_HZ_COMMON && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800639 default n
640 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800641 This option permits CPUs to enter dynticks-idle state even if
642 they have RCU callbacks queued, and prevents RCU from waking
643 these CPUs up more than roughly once every four jiffies (by
644 default, you can adjust this using the rcutree.rcu_idle_gp_delay
645 parameter), thus improving energy efficiency. On the other
646 hand, this option increases the duration of RCU grace periods,
647 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800648
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800649 Say Y if energy efficiency is critically important, and you
650 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800651
652 Say N if you are unsure.
653
Mike Travisc903ff82009-01-15 12:28:29 -0800654config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400655 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800656 select DEBUG_FS
657 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700658 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400659 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700660 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800661
Paul E. McKenney24278d12010-09-27 17:25:23 -0700662config RCU_BOOST
663 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800664 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700665 default n
666 help
667 This option boosts the priority of preempted RCU readers that
668 block the current preemptible RCU grace period for too long.
669 This option also prevents heavy loads from blocking RCU
670 callback invocation for all flavors of RCU.
671
672 Say Y here if you are working with real-time apps or heavy loads
673 Say N here if you are unsure.
674
Clark Williams21871d72014-09-12 21:21:09 -0500675config RCU_KTHREAD_PRIO
676 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800677 range 1 99 if RCU_BOOST
678 range 0 99 if !RCU_BOOST
679 default 1 if RCU_BOOST
680 default 0 if !RCU_BOOST
Paul E. McKenney24278d12010-09-27 17:25:23 -0700681 help
Clark Williams21871d72014-09-12 21:21:09 -0500682 This option specifies the SCHED_FIFO priority value that will be
683 assigned to the rcuc/n and rcub/n threads and is also the value
684 used for RCU_BOOST (if enabled). If you are working with a
685 real-time application that has one or more CPU-bound threads
686 running at a real-time priority level, you should set
687 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
688 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
689 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700690 applications that do not have any CPU-bound threads.
691
692 Some real-time applications might not have a single real-time
693 thread that saturates a given CPU, but instead might have
694 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500695 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700696 a priority higher than the lowest-priority thread that is
697 conspiring to prevent the CPU from running any non-real-time
698 tasks. For example, if one thread at priority 10 and another
699 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500700 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700701 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700702
703 Specify the real-time priority, or take the default if unsure.
704
705config RCU_BOOST_DELAY
706 int "Milliseconds to delay boosting after RCU grace-period start"
707 range 0 3000
708 depends on RCU_BOOST
709 default 500
710 help
711 This option specifies the time to wait after the beginning of
712 a given grace period before priority-boosting preempted RCU
713 readers blocking that grace period. Note that any RCU reader
714 blocking an expedited RCU grace period is boosted immediately.
715
716 Accept the default if unsure.
717
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700718config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700719 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400720 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700721 default n
722 help
723 Use this option to reduce OS jitter for aggressive HPC or
724 real-time workloads. It can also be used to offload RCU
725 callback invocation to energy-efficient CPUs in battery-powered
726 asymmetric multiprocessors.
727
728 This option offloads callback invocation from the set of
729 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800730 For each such CPU, a kthread ("rcuox/N") will be created to
731 invoke callbacks, where the "N" is the CPU being offloaded,
732 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
733 "s" for RCU-sched. Nothing prevents this kthread from running
734 on the specified CPUs, but (1) the kthreads may be preempted
735 between each callback, and (2) affinity or cgroups can be used
736 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700737
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800738 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700739 Say N here if you are unsure.
740
Paul E. McKenney911af502013-02-11 10:23:27 -0800741choice
742 prompt "Build-forced no-CBs CPUs"
743 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200744 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800745 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700746 This option allows no-CBs CPUs (whose RCU callbacks are invoked
747 from kthreads rather than from softirq context) to be specified
748 at build time. Additional no-CBs CPUs may be specified by
749 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800750
751config RCU_NOCB_CPU_NONE
752 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800753 help
754 This option does not force any of the CPUs to be no-CBs CPUs.
755 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700756 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
757 kthreads whose names begin with "rcuo". All other CPUs will
758 invoke their own RCU callbacks in softirq context.
759
760 Select this option if you want to choose no-CBs CPUs at
761 boot time, for example, to allow testing of different no-CBs
762 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800763
764config RCU_NOCB_CPU_ZERO
765 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800766 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700767 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
768 callbacks are invoked by a per-CPU kthread whose name begins
769 with "rcuo". Additional CPUs may be designated as no-CBs
770 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
771 All other CPUs will invoke their own RCU callbacks in softirq
772 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800773
774 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700775 or energy-efficiency reasons, but the real reason it exists
776 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800777
778config RCU_NOCB_CPU_ALL
779 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800780 help
781 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700782 boot parameter will be ignored. All CPUs' RCU callbacks will
783 be executed in the context of per-CPU rcuo kthreads created for
784 this purpose. Assuming that the kthreads whose names start with
785 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
786 on the remaining CPUs, but might decrease memory locality during
787 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800788
789 Select this if all CPUs need to be no-CBs CPUs for real-time
790 or energy-efficiency reasons.
791
792endchoice
793
Mike Travisc903ff82009-01-15 12:28:29 -0800794endmenu # "RCU Subsystem"
795
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700796config BUILD_BIN2C
797 bool
798 default n
799
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700801 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700802 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 ---help---
804 This option enables the complete Linux kernel ".config" file
805 contents to be saved in the kernel. It provides documentation
806 of which kernel options are used in a running kernel or in an
807 on-disk kernel. This information can be extracted from the kernel
808 image file with the script scripts/extract-ikconfig and used as
809 input to rebuild the current kernel or to build another kernel.
810 It can also be extracted from a running kernel by reading
811 /proc/config.gz if enabled (below).
812
813config IKCONFIG_PROC
814 bool "Enable access to .config through /proc/config.gz"
815 depends on IKCONFIG && PROC_FS
816 ---help---
817 This option enables access to the kernel configuration file
818 through /proc/config.gz.
819
Alistair John Strachan794543a2007-05-08 00:31:15 -0700820config LOG_BUF_SHIFT
821 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
822 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700823 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700824 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700825 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700826 Select the minimal kernel log buffer size as a power of 2.
827 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
828 parameter, see below. Any higher size also might be forced
829 by "log_buf_len" boot parameter.
830
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700831 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700832 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700833 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700834 15 => 32 KB
835 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700836 13 => 8 KB
837 12 => 4 KB
838
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700839config LOG_CPU_MAX_BUF_SHIFT
840 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700841 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700842 range 0 21
843 default 12 if !BASE_SMALL
844 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700845 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700846 help
847 This option allows to increase the default ring buffer size
848 according to the number of CPUs. The value defines the contribution
849 of each CPU as a power of 2. The used space is typically only few
850 lines however it might be much more when problems are reported,
851 e.g. backtraces.
852
853 The increased size means that a new buffer has to be allocated and
854 the original static one is unused. It makes sense only on systems
855 with more CPUs. Therefore this value is used only when the sum of
856 contributions is greater than the half of the default kernel ring
857 buffer as defined by LOG_BUF_SHIFT. The default values are set
858 so that more than 64 CPUs are needed to trigger the allocation.
859
860 Also this option is ignored when "log_buf_len" kernel parameter is
861 used as it forces an exact (power of two) size of the ring buffer.
862
863 The number of possible CPUs is used for this computation ignoring
864 hotplugging making the compuation optimal for the the worst case
865 scenerio while allowing a simple algorithm to be used from bootup.
866
867 Examples shift values and their meaning:
868 17 => 128 KB for each CPU
869 16 => 64 KB for each CPU
870 15 => 32 KB for each CPU
871 14 => 16 KB for each CPU
872 13 => 8 KB for each CPU
873 12 => 4 KB for each CPU
874
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800875#
876# Architectures with an unreliable sched_clock() should select this:
877#
878config HAVE_UNSTABLE_SCHED_CLOCK
879 bool
880
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700881config GENERIC_SCHED_CLOCK
882 bool
883
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200884#
885# For architectures that want to enable the support for NUMA-affine scheduler
886# balancing logic:
887#
888config ARCH_SUPPORTS_NUMA_BALANCING
889 bool
890
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100891#
892# For architectures that know their GCC __int128 support is sound
893#
894config ARCH_SUPPORTS_INT128
895 bool
896
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200897# For architectures that (ab)use NUMA to represent different memory regions
898# all cpu-local but of different latencies, such as SuperH.
899#
900config ARCH_WANT_NUMA_VARIABLE_LOCALITY
901 bool
902
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200903config NUMA_BALANCING
904 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200905 depends on ARCH_SUPPORTS_NUMA_BALANCING
906 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
907 depends on SMP && NUMA && MIGRATION
908 help
909 This option adds support for automatic NUMA aware memory/task placement.
910 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400911 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200912
913 This system will be inactive on UMA systems.
914
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800915config NUMA_BALANCING_DEFAULT_ENABLED
916 bool "Automatically enable NUMA aware memory/task placement"
917 default y
918 depends on NUMA_BALANCING
919 help
920 If set, automatic NUMA balancing will be enabled if running on a NUMA
921 machine.
922
Li Zefan23964d22009-01-15 13:50:58 -0800923menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500924 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500925 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700926 help
Li Zefan23964d22009-01-15 13:50:58 -0800927 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800928 use with process control subsystems such as Cpusets, CFS, memory
929 controls or device isolation.
930 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800931 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800932 - Documentation/cgroups/ (features for grouping, isolation
933 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700934
935 Say N if unsure.
936
Li Zefan23964d22009-01-15 13:50:58 -0800937if CGROUPS
938
Paul Menage006cb992007-10-18 23:39:43 -0700939config CGROUP_DEBUG
940 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700941 default n
Paul Menage006cb992007-10-18 23:39:43 -0700942 help
943 This option enables a simple cgroup subsystem that
944 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800945 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700946
Li Zefan23964d22009-01-15 13:50:58 -0800947 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700948
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700949config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800950 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800951 help
952 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700953 cgroup.
954
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700955config CGROUP_DEVICE
956 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700957 help
958 Provides a cgroup implementing whitelists for devices which
959 a process in the cgroup can mknod or open.
960
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961config CPUSETS
962 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700964 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 allow dynamically partitioning a system into sets of CPUs and
966 Memory Nodes and assigning tasks to run only within those sets.
967 This is primarily useful on large SMP or NUMA systems.
968
969 Say N if unsure.
970
Li Zefan23964d22009-01-15 13:50:58 -0800971config PROC_PID_CPUSET
972 bool "Include legacy /proc/<pid>/cpuset file"
973 depends on CPUSETS
974 default y
975
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100976config CGROUP_CPUACCT
977 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100978 help
979 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800980 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100981
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800982config PAGE_COUNTER
983 bool
984
Andrew Mortonc255a452012-07-31 16:43:02 -0700985config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800986 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800987 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500988 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800989 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700990 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100991 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800992
Andrew Mortonc255a452012-07-31 16:43:02 -0700993config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700994 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700995 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800996 help
997 Add swap management feature to memory resource controller. When you
998 enable this, you can limit mem+swap usage per cgroup. In other words,
999 when you disable this, memory resource controller has no cares to
1000 usage of swap...a process can exhaust all of the swap. This extension
1001 is useful when you want to avoid exhaustion swap but this itself
1002 adds more overheads and consumes memory for remembering information.
1003 Especially if you use 32bit system or small memory system, please
1004 be careful about enabling this. When memory resource controller
1005 is disabled by boot option, this will be automatically disabled and
1006 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001007 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001008 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1009 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001010config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001011 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001012 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001013 default y
1014 help
1015 Memory Resource Controller Swap Extension comes with its price in
1016 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001017 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001018 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001019 parameter should have this option unselected.
1020 For those who want to have the feature enabled by default should
1021 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001022 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001023config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001024 bool "Memory Resource Controller Kernel Memory accounting"
1025 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001026 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001027 help
1028 The Kernel Memory extension for Memory Resource Controller can limit
1029 the amount of memory used by kernel objects in the system. Those are
1030 fundamentally different from the entities handled by the standard
1031 Memory Controller, which are page-based, and can be swapped. Users of
1032 the kmem extension can use it to guarantee that no group of processes
1033 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001034
Vladimir Davydov2ee06462014-06-04 16:07:28 -07001035 WARNING: Current implementation lacks reclaim support. That means
1036 allocation attempts will fail when close to the limit even if there
1037 are plenty of kmem available for reclaim. That makes this option
1038 unusable in real life so DO NOT SELECT IT unless for development
1039 purposes.
1040
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001041config CGROUP_HUGETLB
1042 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001043 depends on HUGETLB_PAGE
1044 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001045 default n
1046 help
1047 Provides a cgroup Resource Controller for HugeTLB pages.
1048 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1049 The limit is enforced during page fault. Since HugeTLB doesn't
1050 support page reclaim, enforcing the limit at page fault time implies
1051 that, the application will get SIGBUS signal if it tries to access
1052 HugeTLB pages beyond its limit. This requires the application to know
1053 beforehand how much HugeTLB pages it would require for its use. The
1054 control group is tracked in the third page lru pointer. This means
1055 that we cannot use the controller with huge page less than 3 pages.
1056
Stephane Eraniane5d13672011-02-14 11:20:01 +02001057config CGROUP_PERF
1058 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1059 depends on PERF_EVENTS && CGROUPS
1060 help
1061 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001062 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001063 designated cpu.
1064
1065 Say N if unsure.
1066
Dhaval Giani7c941432010-01-20 13:26:18 +01001067menuconfig CGROUP_SCHED
1068 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001069 default n
1070 help
1071 This feature lets CPU scheduler recognize task groups and control CPU
1072 bandwidth allocation to such task groups. It uses cgroups to group
1073 tasks.
1074
1075if CGROUP_SCHED
1076config FAIR_GROUP_SCHED
1077 bool "Group scheduling for SCHED_OTHER"
1078 depends on CGROUP_SCHED
1079 default CGROUP_SCHED
1080
Paul Turnerab84d312011-07-21 09:43:28 -07001081config CFS_BANDWIDTH
1082 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001083 depends on FAIR_GROUP_SCHED
1084 default n
1085 help
1086 This option allows users to define CPU bandwidth rates (limits) for
1087 tasks running within the fair group scheduler. Groups with no limit
1088 set are considered to be unconstrained and will run with no
1089 restriction.
1090 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1091
Dhaval Giani7c941432010-01-20 13:26:18 +01001092config RT_GROUP_SCHED
1093 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001094 depends on CGROUP_SCHED
1095 default n
1096 help
1097 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001098 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001099 schedule realtime tasks for non-root users until you allocate
1100 realtime bandwidth for them.
1101 See Documentation/scheduler/sched-rt-group.txt for more information.
1102
1103endif #CGROUP_SCHED
1104
Vivek Goyalafc24d42010-04-26 19:27:56 +02001105config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001106 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001107 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001108 default n
1109 ---help---
1110 Generic block IO controller cgroup interface. This is the common
1111 cgroup interface which should be used by various IO controlling
1112 policies.
1113
1114 Currently, CFQ IO scheduler uses it to recognize task groups and
1115 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001116 to such task groups. It is also used by bio throttling logic in
1117 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001118
1119 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001120 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001121 enabling proportional weight division of disk bandwidth in CFQ, set
1122 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001123 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001124
1125 See Documentation/cgroups/blkio-controller.txt for more information.
1126
1127config DEBUG_BLK_CGROUP
1128 bool "Enable Block IO controller debugging"
1129 depends on BLK_CGROUP
1130 default n
1131 ---help---
1132 Enable some debugging help. Currently it exports additional stat
1133 files in a cgroup which can be useful for debugging.
1134
Li Zefan23964d22009-01-15 13:50:58 -08001135endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001136
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001137config CHECKPOINT_RESTORE
1138 bool "Checkpoint/restore support" if EXPERT
1139 default n
1140 help
1141 Enables additional kernel features in a sake of checkpoint/restore.
1142 In particular it adds auxiliary prctl codes to setup process text,
1143 data and heap segment sizes, and a few additional /proc filesystem
1144 entries.
1145
1146 If unsure, say N here.
1147
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001148menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001149 bool "Namespaces support" if EXPERT
1150 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001151 help
1152 Provides the way to make tasks work with different objects using
1153 the same id. For example same IPC id may refer to different objects
1154 or same user id or pid may refer to different tasks when used in
1155 different namespaces.
1156
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001157if NAMESPACES
1158
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001159config UTS_NS
1160 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001161 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001162 help
1163 In this namespace tasks see different info provided with the
1164 uname() system call
1165
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001166config IPC_NS
1167 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001168 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001169 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001170 help
1171 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001172 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001173
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001174config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001175 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001176 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001177 help
1178 This allows containers, i.e. vservers, to use user namespaces
1179 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001180
1181 When user namespaces are enabled in the kernel it is
1182 recommended that the MEMCG and MEMCG_KMEM options also be
1183 enabled and that user-space use the memory control groups to
1184 limit the amount of memory a memory unprivileged users can
1185 use.
1186
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001187 If unsure, say N.
1188
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001189config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001190 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001191 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001192 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001193 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001194 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001195 pid namespaces. This is a building block of containers.
1196
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001197config NET_NS
1198 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001199 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001200 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001201 help
1202 Allow user space to create what appear to be multiple instances
1203 of the network stack.
1204
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001205endif # NAMESPACES
1206
Mike Galbraith5091faa2010-11-30 14:18:03 +01001207config SCHED_AUTOGROUP
1208 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001209 select CGROUPS
1210 select CGROUP_SCHED
1211 select FAIR_GROUP_SCHED
1212 help
1213 This option optimizes the scheduler for common desktop workloads by
1214 automatically creating and populating task groups. This separation
1215 of workloads isolates aggressive CPU burners (like build jobs) from
1216 desktop applications. Task group autogeneration is currently based
1217 upon task session.
1218
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001219config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001220 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001221 depends on SYSFS
1222 default n
1223 help
1224 This option adds code that switches the layout of the "block" class
1225 devices, to not show up in /sys/class/block/, but only in
1226 /sys/block/.
1227
1228 This switch is only active when the sysfs.deprecated=1 boot option is
1229 passed or the SYSFS_DEPRECATED_V2 option is set.
1230
1231 This option allows new kernels to run on old distributions and tools,
1232 which might get confused by /sys/class/block/. Since 2007/2008 all
1233 major distributions and tools handle this just fine.
1234
1235 Recent distributions and userspace tools after 2009/2010 depend on
1236 the existence of /sys/class/block/, and will not work with this
1237 option enabled.
1238
1239 Only if you are using a new kernel on an old distribution, you might
1240 need to say Y here.
1241
1242config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001243 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001244 default n
1245 depends on SYSFS
1246 depends on SYSFS_DEPRECATED
1247 help
1248 Enable deprecated sysfs by default.
1249
1250 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1251 option.
1252
1253 Only if you are using a new kernel on an old distribution, you might
1254 need to say Y here. Even then, odds are you would not need it
1255 enabled, you can always pass the boot option if absolutely necessary.
1256
1257config RELAY
1258 bool "Kernel->user space relay support (formerly relayfs)"
1259 help
1260 This option enables support for relay interface support in
1261 certain file systems (such as debugfs).
1262 It is designed to provide an efficient mechanism for tools and
1263 facilities to relay large amounts of data from kernel space to
1264 user space.
1265
1266 If unsure, say N.
1267
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001268config BLK_DEV_INITRD
1269 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1270 depends on BROKEN || !FRV
1271 help
1272 The initial RAM filesystem is a ramfs which is loaded by the
1273 boot loader (loadlin or lilo) and that is mounted as root
1274 before the normal boot procedure. It is typically used to
1275 load modules needed to mount the "real" root file system,
1276 etc. See <file:Documentation/initrd.txt> for details.
1277
1278 If RAM disk support (BLK_DEV_RAM) is also included, this
1279 also enables initial RAM disk (initrd) support and adds
1280 15 Kbytes (more on some other architectures) to the kernel size.
1281
1282 If unsure say Y.
1283
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001284if BLK_DEV_INITRD
1285
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001286source "usr/Kconfig"
1287
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001288endif
1289
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001290config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001291 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001292 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001293 Enabling this option will pass "-Os" instead of "-O2" to
1294 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001295
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001296 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001297
Randy Dunlap08470622006-09-30 23:28:13 -07001298config SYSCTL
1299 bool
1300
Randy Dunlapb943c462009-03-10 12:55:46 -07001301config ANON_INODES
1302 bool
1303
Mike Frysinger657a5202013-04-30 15:28:45 -07001304config HAVE_UID16
1305 bool
1306
1307config SYSCTL_EXCEPTION_TRACE
1308 bool
1309 help
1310 Enable support for /proc/sys/debug/exception-trace.
1311
1312config SYSCTL_ARCH_UNALIGN_NO_WARN
1313 bool
1314 help
1315 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1316 Allows arch to define/use @no_unaligned_warning to possibly warn
1317 about unaligned access emulation going on under the hood.
1318
1319config SYSCTL_ARCH_UNALIGN_ALLOW
1320 bool
1321 help
1322 Enable support for /proc/sys/kernel/unaligned-trap
1323 Allows arches to define/use @unaligned_enabled to runtime toggle
1324 the unaligned access emulation.
1325 see arch/parisc/kernel/unaligned.c for reference
1326
Mike Frysinger657a5202013-04-30 15:28:45 -07001327config HAVE_PCSPKR_PLATFORM
1328 bool
1329
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001330# interpreter that classic socket filters depend on
1331config BPF
1332 bool
1333
David Rientjes6a108a12011-01-20 14:44:16 -08001334menuconfig EXPERT
1335 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001336 # Unhide debug options, to make the on-by-default options visible
1337 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 help
1339 This option allows certain base kernel options and settings
1340 to be disabled or tweaked. This is for specialized
1341 environments which can tolerate a "non-standard" kernel.
1342 Only use this if you really know what you are doing.
1343
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001344config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001345 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001346 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001347 default y
1348 help
1349 This enables the legacy 16-bit UID syscall wrappers.
1350
Fabian Frederickf6187762014-06-04 16:11:12 -07001351config SGETMASK_SYSCALL
1352 bool "sgetmask/ssetmask syscalls support" if EXPERT
1353 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1354 ---help---
1355 sys_sgetmask and sys_ssetmask are obsolete system calls
1356 no longer supported in libc but still enabled by default in some
1357 architectures.
1358
1359 If unsure, leave the default option here.
1360
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001361config SYSFS_SYSCALL
1362 bool "Sysfs syscall support" if EXPERT
1363 default y
1364 ---help---
1365 sys_sysfs is an obsolete system call no longer supported in libc.
1366 Note that disabling this option is more secure but might break
1367 compatibility with some systems.
1368
1369 If unsure say Y here.
1370
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001371config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001372 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001373 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001374 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001375 select SYSCTL
1376 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001377 sys_sysctl uses binary paths that have been found challenging
1378 to properly maintain and use. The interface in /proc/sys
1379 using paths with ascii names is now the primary path to this
1380 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001381
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001382 Almost nothing using the binary sysctl interface so if you are
1383 trying to save some space it is probably safe to disable this,
1384 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001385
WANG Congc736de62011-11-02 13:39:25 -07001386 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001387
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001389 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390 default y
1391 help
1392 Say Y here to let the kernel print out symbolic crash information and
1393 symbolic stack backtraces. This increases the size of the kernel
1394 somewhat, as all symbols have to be loaded into the kernel image.
1395
1396config KALLSYMS_ALL
1397 bool "Include all symbols in kallsyms"
1398 depends on DEBUG_KERNEL && KALLSYMS
1399 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001400 Normally kallsyms only contains the symbols of functions for nicer
1401 OOPS messages and backtraces (i.e., symbols from the text and inittext
1402 sections). This is sufficient for most cases. And only in very rare
1403 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1404 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001406 This option makes sure that all symbols are loaded into the kernel
1407 image (i.e., symbols from all sections) in cost of increased kernel
1408 size (depending on the kernel configuration, it may be 300KiB or
1409 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001411 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001412
1413config PRINTK
1414 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001415 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001416 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001417 help
1418 This option enables normal printk support. Removing it
1419 eliminates most of the message strings from the kernel image
1420 and makes the kernel more or less silent. As this makes it
1421 very difficult to diagnose system problems, saying N here is
1422 strongly discouraged.
1423
Matt Mackallc8538a72005-05-01 08:59:01 -07001424config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001425 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001426 default y
1427 help
1428 Disabling this option eliminates support for BUG and WARN, reducing
1429 the size of your kernel image and potentially quietly ignoring
1430 numerous fatal conditions. You should only consider disabling this
1431 option for embedded systems with no facilities for reporting errors.
1432 Just say Y.
1433
Matt Mackall708e9a72006-01-08 01:05:25 -08001434config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001435 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001436 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001437 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001438 help
1439 Enable support for generating core dumps. Disabling saves about 4k.
1440
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001441
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001442config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001443 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001444 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001445 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001446 default y
1447 help
1448 This option allows to disable the internal PC-Speaker
1449 support, saving some memory.
1450
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451config BASE_FULL
1452 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001453 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454 help
1455 Disabling this option reduces the size of miscellaneous core
1456 kernel data structures. This saves memory on small machines,
1457 but may reduce performance.
1458
1459config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001460 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001462 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 help
1464 Disabling this option will cause the kernel to be built without
1465 support for "fast userspace mutexes". The resulting kernel may not
1466 run glibc-based applications correctly.
1467
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001468config HAVE_FUTEX_CMPXCHG
1469 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001470 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001471 help
1472 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1473 is implemented and always working. This removes a couple of runtime
1474 checks.
1475
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001477 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001479 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 help
1481 Disabling this option will cause the kernel to be built without
1482 support for epoll family of system calls.
1483
Davide Libenzifba2afa2007-05-10 22:23:13 -07001484config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001485 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001486 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001487 default y
1488 help
1489 Enable the signalfd() system call that allows to receive signals
1490 on a file descriptor.
1491
1492 If unsure, say Y.
1493
Davide Libenzib215e282007-05-10 22:23:16 -07001494config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001495 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001496 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001497 default y
1498 help
1499 Enable the timerfd() system call that allows to receive timer
1500 events on a file descriptor.
1501
1502 If unsure, say Y.
1503
Davide Libenzie1ad7462007-05-10 22:23:19 -07001504config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001505 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001506 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001507 default y
1508 help
1509 Enable the eventfd() system call that allows to receive both
1510 kernel notification (ie. KAIO) or userspace notifications.
1511
1512 If unsure, say Y.
1513
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001514# syscall, maps, verifier
1515config BPF_SYSCALL
1516 bool "Enable bpf() system call" if EXPERT
1517 select ANON_INODES
1518 select BPF
1519 default n
1520 help
1521 Enable the bpf() system call that allows to manipulate eBPF
1522 programs and maps via file descriptors.
1523
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001525 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 default y
1527 depends on MMU
1528 help
1529 The shmem is an internal filesystem used to manage shared memory.
1530 It is backed by swap and manages resource limits. It is also exported
1531 to userspace as tmpfs if TMPFS is enabled. Disabling this
1532 option replaces shmem and tmpfs with the much simpler ramfs code,
1533 which may be appropriate on small systems without swap.
1534
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001535config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001536 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001537 default y
1538 help
1539 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001540 by some high performance threaded applications. Disabling
1541 this option saves about 7k.
1542
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001543config ADVISE_SYSCALLS
1544 bool "Enable madvise/fadvise syscalls" if EXPERT
1545 default y
1546 help
1547 This option enables the madvise and fadvise syscalls, used by
1548 applications to advise the kernel about their future memory or file
1549 usage, improving performance. If building an embedded system where no
1550 applications use these syscalls, you can disable this option to save
1551 space.
1552
Mike Frysinger657a5202013-04-30 15:28:45 -07001553config PCI_QUIRKS
1554 default y
1555 bool "Enable PCI quirk workarounds" if EXPERT
1556 depends on PCI
1557 help
1558 This enables workarounds for various PCI chipset
1559 bugs/quirks. Disable this only if your target machine is
1560 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001561
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001562config EMBEDDED
1563 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001564 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001565 select EXPERT
1566 help
1567 This option should be enabled if compiling the kernel for
1568 an embedded system so certain expert options are available
1569 for configuration.
1570
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001571config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001572 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001573 help
1574 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001575
Peter Zijlstra906010b2009-09-21 16:08:49 +02001576config PERF_USE_VMALLOC
1577 bool
1578 help
1579 See tools/perf/design.txt for details
1580
Ingo Molnar57c0c152009-09-21 12:20:38 +02001581menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001582
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001583config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001584 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001585 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001586 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001587 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001588 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001589 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001590 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001591 Enable kernel support for various performance events provided
1592 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001593
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001594 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001595 use of generic tracepoints.
1596
1597 Most modern CPUs support performance events via performance
1598 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001599 types of hw events: such as instructions executed, cachemisses
1600 suffered, or branches mis-predicted - without slowing down the
1601 kernel or applications. These registers can also trigger interrupts
1602 when a threshold number of events have passed - and can thus be
1603 used to profile the code that runs on that CPU.
1604
Ingo Molnar57c0c152009-09-21 12:20:38 +02001605 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001606 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001607 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001608 provides per task and per CPU counters, and it provides event
1609 capabilities on top of those.
1610
1611 Say Y if unsure.
1612
Peter Zijlstra906010b2009-09-21 16:08:49 +02001613config DEBUG_PERF_USE_VMALLOC
1614 default n
1615 bool "Debug: use vmalloc to back perf mmap() buffers"
1616 depends on PERF_EVENTS && DEBUG_KERNEL
1617 select PERF_USE_VMALLOC
1618 help
1619 Use vmalloc memory to back perf mmap() buffers.
1620
1621 Mostly useful for debugging the vmalloc code on platforms
1622 that don't require it.
1623
1624 Say N if unsure.
1625
Thomas Gleixner0793a612008-12-04 20:12:29 +01001626endmenu
1627
Christoph Lameterf8891e52006-06-30 01:55:45 -07001628config VM_EVENT_COUNTERS
1629 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001630 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001631 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001632 VM event counters are needed for event counts to be shown.
1633 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001634 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001635 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001636
Christoph Lameter41ecc552007-05-09 02:32:44 -07001637config SLUB_DEBUG
1638 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001639 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001640 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001641 help
1642 SLUB has extensive debug support features. Disabling these can
1643 result in significant savings in code size. This also disables
1644 SLUB sysfs support. /sys/slab will not exist and there will be
1645 no support for cache validation etc.
1646
Randy Dunlapb943c462009-03-10 12:55:46 -07001647config COMPAT_BRK
1648 bool "Disable heap randomization"
1649 default y
1650 help
1651 Randomizing heap placement makes heap exploits harder, but it
1652 also breaks ancient binaries (including anything libc5 based).
1653 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001654 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001655 /proc/sys/kernel/randomize_va_space to 2.
1656
1657 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1658
Christoph Lameter81819f02007-05-06 14:49:36 -07001659choice
1660 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001661 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001662 help
1663 This option allows to select a slab allocator.
1664
1665config SLAB
1666 bool "SLAB"
1667 help
1668 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001669 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001670 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001671
1672config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001673 bool "SLUB (Unqueued Allocator)"
1674 help
1675 SLUB is a slab allocator that minimizes cache line usage
1676 instead of managing queues of cached objects (SLAB approach).
1677 Per cpu caching is realized using slabs of objects instead
1678 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001679 and has enhanced diagnostics. SLUB is the default choice for
1680 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001681
1682config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001683 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001684 bool "SLOB (Simple Allocator)"
1685 help
Matt Mackall37291452008-02-04 22:29:38 -08001686 SLOB replaces the stock allocator with a drastically simpler
1687 allocator. SLOB is generally more space efficient but
1688 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001689
1690endchoice
1691
Joonsoo Kim345c9052013-06-19 14:05:52 +09001692config SLUB_CPU_PARTIAL
1693 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001694 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001695 bool "SLUB per cpu partial cache"
1696 help
1697 Per cpu partial caches accellerate objects allocation and freeing
1698 that is local to a processor at the price of more indeterminism
1699 in the latency of the free. On overflow these caches will be cleared
1700 which requires the taking of locks that may cause latency spikes.
1701 Typically one would choose no for a realtime system.
1702
Jie Zhangea637632009-12-14 18:00:02 -08001703config MMAP_ALLOW_UNINITIALIZED
1704 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001705 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001706 default n
1707 help
1708 Normally, and according to the Linux spec, anonymous memory obtained
1709 from mmap() has it's contents cleared before it is passed to
1710 userspace. Enabling this config option allows you to request that
1711 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1712 providing a huge performance boost. If this option is not enabled,
1713 then the flag will be ignored.
1714
1715 This is taken advantage of by uClibc's malloc(), and also by
1716 ELF-FDPIC binfmt's brk and stack allocator.
1717
1718 Because of the obvious security issues, this option should only be
1719 enabled on embedded devices where you control what is run in
1720 userspace. Since that isn't generally a problem on no-MMU systems,
1721 it is normally safe to say Y here.
1722
1723 See Documentation/nommu-mmap.txt for more information.
1724
Peter Foley82c04ff2014-04-18 15:07:11 -07001725config SYSTEM_TRUSTED_KEYRING
1726 bool "Provide system-wide ring of trusted keys"
1727 depends on KEYS
1728 help
1729 Provide a system keyring to which trusted keys can be added. Keys in
1730 the keyring are considered to be trusted. Keys may be added at will
1731 by the kernel from compiled-in data and from hardware key stores, but
1732 userspace may only add extra keys if those keys can be verified by
1733 keys already in the keyring.
1734
1735 Keys in this keyring are used by module signature checking.
1736
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001737config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001738 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001739 help
1740 Say Y here to enable the extended profiling support mechanisms used
1741 by profilers such as OProfile.
1742
Ingo Molnar5f87f112008-07-23 14:15:22 +02001743#
1744# Place an empty function call at each tracepoint site. Can be
1745# dynamically changed for a probe function.
1746#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001747config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001748 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001749
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001750source "arch/Kconfig"
1751
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752endmenu # General setup
1753
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001754config HAVE_GENERIC_DMA_COHERENT
1755 bool
1756 default n
1757
Linus Torvalds158a9622008-01-02 13:04:48 -08001758config SLABINFO
1759 bool
1760 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001761 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001762 default y
1763
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001764config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001765 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001766
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767config BASE_SMALL
1768 int
1769 default 0 if BASE_FULL
1770 default 1 if !BASE_FULL
1771
Jan Engelhardt66da5732007-07-15 23:39:29 -07001772menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001774 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 help
1776 Kernel modules are small pieces of compiled code which can
1777 be inserted in the running kernel, rather than being
1778 permanently built into the kernel. You use the "modprobe"
1779 tool to add (and sometimes remove) them. If you say Y here,
1780 many parts of the kernel can be built as modules (by
1781 answering M instead of Y where indicated): this is most
1782 useful for infrequently used options which are not required
1783 for booting. For more information, see the man pages for
1784 modprobe, lsmod, modinfo, insmod and rmmod.
1785
1786 If you say Y here, you will need to run "make
1787 modules_install" to put the modules under /lib/modules/
1788 where modprobe can find them (you may need to be root to do
1789 this).
1790
1791 If unsure, say Y.
1792
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001793if MODULES
1794
Linus Torvalds826e4502008-05-04 17:04:16 -07001795config MODULE_FORCE_LOAD
1796 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001797 default n
1798 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001799 Allow loading of modules without version information (ie. modprobe
1800 --force). Forced module loading sets the 'F' (forced) taint flag and
1801 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001802
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803config MODULE_UNLOAD
1804 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805 help
1806 Without this option you will not be able to unload any
1807 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001808 anyway), which makes your kernel smaller, faster
1809 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810
1811config MODULE_FORCE_UNLOAD
1812 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001813 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 help
1815 This option allows you to force a module to unload, even if the
1816 kernel believes it is unsafe: the kernel will remove the module
1817 without waiting for anyone to stop using it (using the -f option to
1818 rmmod). This is mainly for kernel developers and desperate users.
1819 If unsure, say N.
1820
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001822 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 help
1824 Usually, you have to use modules compiled with your kernel.
1825 Saying Y here makes it sometimes possible to use modules
1826 compiled for different kernels, by adding enough information
1827 to the modules to (hopefully) spot any changes which would
1828 make them incompatible with the kernel you are running. If
1829 unsure, say N.
1830
1831config MODULE_SRCVERSION_ALL
1832 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 help
1834 Modules which contain a MODULE_VERSION get an extra "srcversion"
1835 field inserted into their modinfo section, which contains a
1836 sum of the source files which made it. This helps maintainers
1837 see exactly which source was used to build a module (since
1838 others sometimes change the module source without updating
1839 the version). With this option, such a "srcversion" field
1840 will be created for all modules. If unsure, say N.
1841
Rusty Russell106a4ee2012-09-26 10:09:40 +01001842config MODULE_SIG
1843 bool "Module signature verification"
1844 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001845 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001846 select KEYS
1847 select CRYPTO
1848 select ASYMMETRIC_KEY_TYPE
1849 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1850 select PUBLIC_KEY_ALGO_RSA
1851 select ASN1
1852 select OID_REGISTRY
1853 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001854 help
1855 Check modules for valid signatures upon load: the signature
1856 is simply appended to the module. For more information see
1857 Documentation/module-signing.txt.
1858
David Howellsea0b6dc2012-09-26 10:09:50 +01001859 !!!WARNING!!! If you enable this option, you MUST make sure that the
1860 module DOES NOT get stripped after being signed. This includes the
1861 debuginfo strip done by some packagers (such as rpmbuild) and
1862 inclusion into an initramfs that wants the module size reduced.
1863
Rusty Russell106a4ee2012-09-26 10:09:40 +01001864config MODULE_SIG_FORCE
1865 bool "Require modules to be validly signed"
1866 depends on MODULE_SIG
1867 help
1868 Reject unsigned modules or signed modules for which we don't have a
1869 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001870
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301871config MODULE_SIG_ALL
1872 bool "Automatically sign all modules"
1873 default y
1874 depends on MODULE_SIG
1875 help
1876 Sign all modules during make modules_install. Without this option,
1877 modules must be signed manually, using the scripts/sign-file tool.
1878
1879comment "Do not forget to sign required modules with scripts/sign-file"
1880 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1881
David Howellsea0b6dc2012-09-26 10:09:50 +01001882choice
1883 prompt "Which hash algorithm should modules be signed with?"
1884 depends on MODULE_SIG
1885 help
1886 This determines which sort of hashing algorithm will be used during
1887 signature generation. This algorithm _must_ be built into the kernel
1888 directly so that signature verification can take place. It is not
1889 possible to load a signed module containing the algorithm to check
1890 the signature on that module.
1891
1892config MODULE_SIG_SHA1
1893 bool "Sign modules with SHA-1"
1894 select CRYPTO_SHA1
1895
1896config MODULE_SIG_SHA224
1897 bool "Sign modules with SHA-224"
1898 select CRYPTO_SHA256
1899
1900config MODULE_SIG_SHA256
1901 bool "Sign modules with SHA-256"
1902 select CRYPTO_SHA256
1903
1904config MODULE_SIG_SHA384
1905 bool "Sign modules with SHA-384"
1906 select CRYPTO_SHA512
1907
1908config MODULE_SIG_SHA512
1909 bool "Sign modules with SHA-512"
1910 select CRYPTO_SHA512
1911
1912endchoice
1913
Michal Marek22753672013-01-25 13:41:00 +10301914config MODULE_SIG_HASH
1915 string
1916 depends on MODULE_SIG
1917 default "sha1" if MODULE_SIG_SHA1
1918 default "sha224" if MODULE_SIG_SHA224
1919 default "sha256" if MODULE_SIG_SHA256
1920 default "sha384" if MODULE_SIG_SHA384
1921 default "sha512" if MODULE_SIG_SHA512
1922
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301923config MODULE_COMPRESS
1924 bool "Compress modules on installation"
1925 depends on MODULES
1926 help
1927 This option compresses the kernel modules when 'make
1928 modules_install' is run.
1929
1930 The modules will be compressed either using gzip or xz depend on the
1931 choice made in "Compression algorithm".
1932
1933 module-init-tools has support for gzip format while kmod handle gzip
1934 and xz compressed modules.
1935
1936 When a kernel module is installed from outside of the main kernel
1937 source and uses the Kbuild system for installing modules then that
1938 kernel module will also be compressed when it is installed.
1939
1940 This option provides little benefit when the modules are to be used inside
1941 an initrd or initramfs, it generally is more efficient to compress the whole
1942 initrd or initramfs instead.
1943
1944 This is fully compatible with signed modules while the signed module is
1945 compressed. module-init-tools or kmod handles decompression and provide to
1946 other layer the uncompressed but signed payload.
1947
1948choice
1949 prompt "Compression algorithm"
1950 depends on MODULE_COMPRESS
1951 default MODULE_COMPRESS_GZIP
1952 help
1953 This determines which sort of compression will be used during
1954 'make modules_install'.
1955
1956 GZIP (default) and XZ are supported.
1957
1958config MODULE_COMPRESS_GZIP
1959 bool "GZIP"
1960
1961config MODULE_COMPRESS_XZ
1962 bool "XZ"
1963
1964endchoice
1965
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001966endif # MODULES
1967
Rusty Russell98a79d62008-12-13 21:19:41 +10301968config INIT_ALL_POSSIBLE
1969 bool
1970 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301971 Back when each arch used to define their own cpu_online_mask and
1972 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301973 with all 1s, and others with all 0s. When they were centralised,
1974 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001975 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301976
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977config STOP_MACHINE
1978 bool
1979 default y
1980 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1981 help
1982 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001983
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001984source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001985
1986config PREEMPT_NOTIFIERS
1987 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001988
Steffen Klassert16295be2010-01-06 19:47:10 +11001989config PADATA
1990 depends on SMP
1991 bool
1992
Andi Kleen754b7b62012-10-04 17:11:27 -07001993# Can be selected by architectures with broken toolchains
1994# that get confused by correct const<->read_only section
1995# mappings
1996config BROKEN_RODATA
1997 bool
1998
David Howells4520c6a2012-09-21 23:31:13 +01001999config ASN1
2000 tristate
2001 help
2002 Build a simple ASN.1 grammar compiler that produces a bytecode output
2003 that can be interpreted by the ASN.1 stream decoder and used to
2004 inform it as to what tags are to be expected in a stream and what
2005 functions to call on what tags.
2006
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002007source "kernel/Kconfig.locks"