blob: a60d1442d1dfab81190280e2cf25c08295ff0fe6 [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
Steven Rostedt016a8d52013-05-28 17:32:53 -0400473 select IRQ_WORK
Mike Travisc903ff82009-01-15 12:28:29 -0800474 help
475 This option selects the RCU implementation that is
476 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700477 thousands of CPUs. It also scales down nicely to
478 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800479
Pranith Kumar28f65692014-09-22 14:00:48 -0400480config PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700481 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800482 depends on PREEMPT
James Hogan53614712013-07-25 15:34:25 +0100483 select IRQ_WORK
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700484 help
485 This option selects the RCU implementation that is
486 designed for very large SMP systems with hundreds or
487 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700488 is also required. It also scales down nicely to
489 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700490
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800491 Select this option if you are unsure.
492
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700493config TINY_RCU
494 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700495 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700496 help
497 This option selects the RCU implementation that is
498 designed for UP systems from which real-time response
499 is not required. This option greatly reduces the
500 memory footprint of RCU.
501
Mike Travisc903ff82009-01-15 12:28:29 -0800502endchoice
503
Paul E. McKenney8315f422014-06-27 13:42:20 -0700504config TASKS_RCU
505 bool "Task_based RCU implementation using voluntary context switch"
506 default n
507 help
508 This option enables a task-based RCU implementation that uses
509 only voluntary context switch (not preemption!), idle, and
510 user-mode execution as quiescent states.
511
512 If unsure, say N.
513
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700514config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400515 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700516 help
517 This option enables RCU CPU stall code that is common between
518 the TINY and TREE variants of RCU. The purpose is to allow
519 the tiny variants to disable RCU CPU stall warnings, while
520 making these warnings mandatory for the tree variants.
521
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100522config CONTEXT_TRACKING
523 bool
524
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200525config RCU_USER_QS
526 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100527 depends on HAVE_CONTEXT_TRACKING && SMP
528 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200529 help
530 This option sets hooks on kernel / userspace boundaries and
531 puts RCU in extended quiescent state when the CPU runs in
532 userspace. It means that when a CPU runs in userspace, it is
533 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700534 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200535
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200536 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100537 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700538 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200539
540 If unsure say N
541
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100542config CONTEXT_TRACKING_FORCE
543 bool "Force context tracking"
544 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200545 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200546 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200547 The major pre-requirement for full dynticks to work is to
548 support the context tracking subsystem. But there are also
549 other dependencies to provide in order to make the full
550 dynticks working.
551
552 This option stands for testing when an arch implements the
553 context tracking backend but doesn't yet fullfill all the
554 requirements to make the full dynticks feature working.
555 Without the full dynticks, there is no way to test the support
556 for context tracking and the subsystems that rely on it: RCU
557 userspace extended quiescent state and tickless cputime
558 accounting. This option copes with the absence of the full
559 dynticks subsystem by forcing the context tracking on all
560 CPUs in the system.
561
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400562 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200563 architecture backend for the context tracking.
564
565 Say N otherwise, this option brings an overhead that you
566 don't want in production.
567
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200568
Mike Travisc903ff82009-01-15 12:28:29 -0800569config RCU_FANOUT
570 int "Tree-based hierarchical RCU fanout value"
571 range 2 64 if 64BIT
572 range 2 32 if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400573 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800574 default 64 if 64BIT
575 default 32 if !64BIT
576 help
577 This option controls the fanout of hierarchical implementations
578 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700579 large numbers of CPUs. This value must be at least the fourth
580 root of NR_CPUS, which allows NR_CPUS to be insanely large.
581 The default value of RCU_FANOUT should be used for production
582 systems, but if you are stress-testing the RCU implementation
583 itself, small RCU_FANOUT values allow you to test large-system
584 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800585
586 Select a specific number if testing RCU itself.
587 Take the default if unsure.
588
Paul E. McKenney8932a632012-04-19 12:20:14 -0700589config RCU_FANOUT_LEAF
590 int "Tree-based hierarchical RCU leaf-level fanout value"
591 range 2 RCU_FANOUT if 64BIT
592 range 2 RCU_FANOUT if !64BIT
Pranith Kumar28f65692014-09-22 14:00:48 -0400593 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney8932a632012-04-19 12:20:14 -0700594 default 16
595 help
596 This option controls the leaf-level fanout of hierarchical
597 implementations of RCU, and allows trading off cache misses
598 against lock contention. Systems that synchronize their
599 scheduling-clock interrupts for energy-efficiency reasons will
600 want the default because the smaller leaf-level fanout keeps
601 lock contention levels acceptably low. Very large systems
602 (hundreds or thousands of CPUs) will instead want to set this
603 value to the maximum value possible in order to reduce the
604 number of cache misses incurred during RCU's grace-period
605 initialization. These systems tend to run CPU-bound, and thus
606 are not helped by synchronized interrupts, and thus tend to
607 skew them, which reduces lock contention enough that large
608 leaf-level fanouts work well.
609
610 Select a specific number if testing RCU itself.
611
612 Select the maximum permissible value for large systems.
613
614 Take the default if unsure.
615
Mike Travisc903ff82009-01-15 12:28:29 -0800616config RCU_FANOUT_EXACT
617 bool "Disable tree-based hierarchical RCU auto-balancing"
Pranith Kumar28f65692014-09-22 14:00:48 -0400618 depends on TREE_RCU || PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800619 default n
620 help
621 This option forces use of the exact RCU_FANOUT value specified,
622 regardless of imbalances in the hierarchy. This is useful for
623 testing RCU itself, and might one day be useful on systems with
624 strong NUMA behavior.
625
626 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
627
628 Say N if unsure.
629
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800630config RCU_FAST_NO_HZ
631 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Frederic Weisbecker3451d022011-08-10 23:21:01 +0200632 depends on NO_HZ_COMMON && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800633 default n
634 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800635 This option permits CPUs to enter dynticks-idle state even if
636 they have RCU callbacks queued, and prevents RCU from waking
637 these CPUs up more than roughly once every four jiffies (by
638 default, you can adjust this using the rcutree.rcu_idle_gp_delay
639 parameter), thus improving energy efficiency. On the other
640 hand, this option increases the duration of RCU grace periods,
641 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800642
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800643 Say Y if energy efficiency is critically important, and you
644 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800645
646 Say N if you are unsure.
647
Mike Travisc903ff82009-01-15 12:28:29 -0800648config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400649 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800650 select DEBUG_FS
651 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700652 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400653 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700654 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800655
Paul E. McKenney24278d12010-09-27 17:25:23 -0700656config RCU_BOOST
657 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800658 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700659 default n
660 help
661 This option boosts the priority of preempted RCU readers that
662 block the current preemptible RCU grace period for too long.
663 This option also prevents heavy loads from blocking RCU
664 callback invocation for all flavors of RCU.
665
666 Say Y here if you are working with real-time apps or heavy loads
667 Say N here if you are unsure.
668
Clark Williams21871d72014-09-12 21:21:09 -0500669config RCU_KTHREAD_PRIO
670 int "Real-time priority to use for RCU worker threads"
Paul E. McKenney24278d12010-09-27 17:25:23 -0700671 range 1 99
672 depends on RCU_BOOST
673 default 1
674 help
Clark Williams21871d72014-09-12 21:21:09 -0500675 This option specifies the SCHED_FIFO priority value that will be
676 assigned to the rcuc/n and rcub/n threads and is also the value
677 used for RCU_BOOST (if enabled). If you are working with a
678 real-time application that has one or more CPU-bound threads
679 running at a real-time priority level, you should set
680 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
681 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
682 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700683 applications that do not have any CPU-bound threads.
684
685 Some real-time applications might not have a single real-time
686 thread that saturates a given CPU, but instead might have
687 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500688 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700689 a priority higher than the lowest-priority thread that is
690 conspiring to prevent the CPU from running any non-real-time
691 tasks. For example, if one thread at priority 10 and another
692 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500693 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700694 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700695
696 Specify the real-time priority, or take the default if unsure.
697
698config RCU_BOOST_DELAY
699 int "Milliseconds to delay boosting after RCU grace-period start"
700 range 0 3000
701 depends on RCU_BOOST
702 default 500
703 help
704 This option specifies the time to wait after the beginning of
705 a given grace period before priority-boosting preempted RCU
706 readers blocking that grace period. Note that any RCU reader
707 blocking an expedited RCU grace period is boosted immediately.
708
709 Accept the default if unsure.
710
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700711config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700712 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400713 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700714 default n
715 help
716 Use this option to reduce OS jitter for aggressive HPC or
717 real-time workloads. It can also be used to offload RCU
718 callback invocation to energy-efficient CPUs in battery-powered
719 asymmetric multiprocessors.
720
721 This option offloads callback invocation from the set of
722 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800723 For each such CPU, a kthread ("rcuox/N") will be created to
724 invoke callbacks, where the "N" is the CPU being offloaded,
725 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
726 "s" for RCU-sched. Nothing prevents this kthread from running
727 on the specified CPUs, but (1) the kthreads may be preempted
728 between each callback, and (2) affinity or cgroups can be used
729 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700730
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800731 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700732 Say N here if you are unsure.
733
Paul E. McKenney911af502013-02-11 10:23:27 -0800734choice
735 prompt "Build-forced no-CBs CPUs"
736 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200737 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800738 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700739 This option allows no-CBs CPUs (whose RCU callbacks are invoked
740 from kthreads rather than from softirq context) to be specified
741 at build time. Additional no-CBs CPUs may be specified by
742 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800743
744config RCU_NOCB_CPU_NONE
745 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800746 help
747 This option does not force any of the CPUs to be no-CBs CPUs.
748 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700749 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
750 kthreads whose names begin with "rcuo". All other CPUs will
751 invoke their own RCU callbacks in softirq context.
752
753 Select this option if you want to choose no-CBs CPUs at
754 boot time, for example, to allow testing of different no-CBs
755 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800756
757config RCU_NOCB_CPU_ZERO
758 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800759 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700760 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
761 callbacks are invoked by a per-CPU kthread whose name begins
762 with "rcuo". Additional CPUs may be designated as no-CBs
763 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
764 All other CPUs will invoke their own RCU callbacks in softirq
765 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800766
767 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700768 or energy-efficiency reasons, but the real reason it exists
769 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800770
771config RCU_NOCB_CPU_ALL
772 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800773 help
774 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700775 boot parameter will be ignored. All CPUs' RCU callbacks will
776 be executed in the context of per-CPU rcuo kthreads created for
777 this purpose. Assuming that the kthreads whose names start with
778 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
779 on the remaining CPUs, but might decrease memory locality during
780 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800781
782 Select this if all CPUs need to be no-CBs CPUs for real-time
783 or energy-efficiency reasons.
784
785endchoice
786
Mike Travisc903ff82009-01-15 12:28:29 -0800787endmenu # "RCU Subsystem"
788
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700789config BUILD_BIN2C
790 bool
791 default n
792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700794 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700795 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 ---help---
797 This option enables the complete Linux kernel ".config" file
798 contents to be saved in the kernel. It provides documentation
799 of which kernel options are used in a running kernel or in an
800 on-disk kernel. This information can be extracted from the kernel
801 image file with the script scripts/extract-ikconfig and used as
802 input to rebuild the current kernel or to build another kernel.
803 It can also be extracted from a running kernel by reading
804 /proc/config.gz if enabled (below).
805
806config IKCONFIG_PROC
807 bool "Enable access to .config through /proc/config.gz"
808 depends on IKCONFIG && PROC_FS
809 ---help---
810 This option enables access to the kernel configuration file
811 through /proc/config.gz.
812
Alistair John Strachan794543a2007-05-08 00:31:15 -0700813config LOG_BUF_SHIFT
814 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
815 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700816 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700817 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700818 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700819 Select the minimal kernel log buffer size as a power of 2.
820 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
821 parameter, see below. Any higher size also might be forced
822 by "log_buf_len" boot parameter.
823
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700824 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700825 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700826 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700827 15 => 32 KB
828 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700829 13 => 8 KB
830 12 => 4 KB
831
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700832config LOG_CPU_MAX_BUF_SHIFT
833 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700834 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700835 range 0 21
836 default 12 if !BASE_SMALL
837 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700838 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700839 help
840 This option allows to increase the default ring buffer size
841 according to the number of CPUs. The value defines the contribution
842 of each CPU as a power of 2. The used space is typically only few
843 lines however it might be much more when problems are reported,
844 e.g. backtraces.
845
846 The increased size means that a new buffer has to be allocated and
847 the original static one is unused. It makes sense only on systems
848 with more CPUs. Therefore this value is used only when the sum of
849 contributions is greater than the half of the default kernel ring
850 buffer as defined by LOG_BUF_SHIFT. The default values are set
851 so that more than 64 CPUs are needed to trigger the allocation.
852
853 Also this option is ignored when "log_buf_len" kernel parameter is
854 used as it forces an exact (power of two) size of the ring buffer.
855
856 The number of possible CPUs is used for this computation ignoring
857 hotplugging making the compuation optimal for the the worst case
858 scenerio while allowing a simple algorithm to be used from bootup.
859
860 Examples shift values and their meaning:
861 17 => 128 KB for each CPU
862 16 => 64 KB for each CPU
863 15 => 32 KB for each CPU
864 14 => 16 KB for each CPU
865 13 => 8 KB for each CPU
866 12 => 4 KB for each CPU
867
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800868#
869# Architectures with an unreliable sched_clock() should select this:
870#
871config HAVE_UNSTABLE_SCHED_CLOCK
872 bool
873
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700874config GENERIC_SCHED_CLOCK
875 bool
876
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200877#
878# For architectures that want to enable the support for NUMA-affine scheduler
879# balancing logic:
880#
881config ARCH_SUPPORTS_NUMA_BALANCING
882 bool
883
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100884#
885# For architectures that know their GCC __int128 support is sound
886#
887config ARCH_SUPPORTS_INT128
888 bool
889
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200890# For architectures that (ab)use NUMA to represent different memory regions
891# all cpu-local but of different latencies, such as SuperH.
892#
893config ARCH_WANT_NUMA_VARIABLE_LOCALITY
894 bool
895
Mel Gorman1a687c22012-11-22 11:16:36 +0000896config NUMA_BALANCING_DEFAULT_ENABLED
897 bool "Automatically enable NUMA aware memory/task placement"
898 default y
899 depends on NUMA_BALANCING
900 help
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400901 If set, automatic NUMA balancing will be enabled if running on a NUMA
Mel Gorman1a687c22012-11-22 11:16:36 +0000902 machine.
903
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904config NUMA_BALANCING
905 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200906 depends on ARCH_SUPPORTS_NUMA_BALANCING
907 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
908 depends on SMP && NUMA && MIGRATION
909 help
910 This option adds support for automatic NUMA aware memory/task placement.
911 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400912 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200913
914 This system will be inactive on UMA systems.
915
Li Zefan23964d22009-01-15 13:50:58 -0800916menuconfig CGROUPS
917 boolean "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500918 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700919 help
Li Zefan23964d22009-01-15 13:50:58 -0800920 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800921 use with process control subsystems such as Cpusets, CFS, memory
922 controls or device isolation.
923 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800924 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800925 - Documentation/cgroups/ (features for grouping, isolation
926 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700927
928 Say N if unsure.
929
Li Zefan23964d22009-01-15 13:50:58 -0800930if CGROUPS
931
Paul Menage006cb992007-10-18 23:39:43 -0700932config CGROUP_DEBUG
933 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700934 default n
Paul Menage006cb992007-10-18 23:39:43 -0700935 help
936 This option enables a simple cgroup subsystem that
937 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800938 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700939
Li Zefan23964d22009-01-15 13:50:58 -0800940 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700941
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700942config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800943 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800944 help
945 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700946 cgroup.
947
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700948config CGROUP_DEVICE
949 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700950 help
951 Provides a cgroup implementing whitelists for devices which
952 a process in the cgroup can mknod or open.
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954config CPUSETS
955 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700957 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 allow dynamically partitioning a system into sets of CPUs and
959 Memory Nodes and assigning tasks to run only within those sets.
960 This is primarily useful on large SMP or NUMA systems.
961
962 Say N if unsure.
963
Li Zefan23964d22009-01-15 13:50:58 -0800964config PROC_PID_CPUSET
965 bool "Include legacy /proc/<pid>/cpuset file"
966 depends on CPUSETS
967 default y
968
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100969config CGROUP_CPUACCT
970 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100971 help
972 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800973 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100974
Pavel Emelianove552b662008-02-07 00:13:49 -0800975config RESOURCE_COUNTERS
976 bool "Resource counters"
977 help
978 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800979 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800980
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800981config PAGE_COUNTER
982 bool
983
Andrew Mortonc255a452012-07-31 16:43:02 -0700984config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800985 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800986 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500987 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800988 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700989 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100990 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800991
992 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700993 associated with each page of memory in the system. By this,
Sergey Dyaslyf60e2a92013-07-03 15:03:30 -0700994 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700995 usage tracking struct at boot. Total amount of this is printed out
996 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800997
998 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700999 sure you need the memory resource controller. Even when you enable
1000 this, you can set "cgroup_disable=memory" at your boot option to
1001 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -08001002 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -08001003
Andrew Mortonc255a452012-07-31 16:43:02 -07001004config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001005 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001006 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001007 help
1008 Add swap management feature to memory resource controller. When you
1009 enable this, you can limit mem+swap usage per cgroup. In other words,
1010 when you disable this, memory resource controller has no cares to
1011 usage of swap...a process can exhaust all of the swap. This extension
1012 is useful when you want to avoid exhaustion swap but this itself
1013 adds more overheads and consumes memory for remembering information.
1014 Especially if you use 32bit system or small memory system, please
1015 be careful about enabling this. When memory resource controller
1016 is disabled by boot option, this will be automatically disabled and
1017 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001018 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001019 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1020 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001021config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001022 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001023 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001024 default y
1025 help
1026 Memory Resource Controller Swap Extension comes with its price in
1027 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001028 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001029 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001030 parameter should have this option unselected.
1031 For those who want to have the feature enabled by default should
1032 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001033 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001034config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001035 bool "Memory Resource Controller Kernel Memory accounting"
1036 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001037 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001038 help
1039 The Kernel Memory extension for Memory Resource Controller can limit
1040 the amount of memory used by kernel objects in the system. Those are
1041 fundamentally different from the entities handled by the standard
1042 Memory Controller, which are page-based, and can be swapped. Users of
1043 the kmem extension can use it to guarantee that no group of processes
1044 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001045
Vladimir Davydov2ee06462014-06-04 16:07:28 -07001046 WARNING: Current implementation lacks reclaim support. That means
1047 allocation attempts will fail when close to the limit even if there
1048 are plenty of kmem available for reclaim. That makes this option
1049 unusable in real life so DO NOT SELECT IT unless for development
1050 purposes.
1051
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001052config CGROUP_HUGETLB
1053 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001054 depends on HUGETLB_PAGE
1055 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001056 default n
1057 help
1058 Provides a cgroup Resource Controller for HugeTLB pages.
1059 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1060 The limit is enforced during page fault. Since HugeTLB doesn't
1061 support page reclaim, enforcing the limit at page fault time implies
1062 that, the application will get SIGBUS signal if it tries to access
1063 HugeTLB pages beyond its limit. This requires the application to know
1064 beforehand how much HugeTLB pages it would require for its use. The
1065 control group is tracked in the third page lru pointer. This means
1066 that we cannot use the controller with huge page less than 3 pages.
1067
Stephane Eraniane5d13672011-02-14 11:20:01 +02001068config CGROUP_PERF
1069 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1070 depends on PERF_EVENTS && CGROUPS
1071 help
1072 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001073 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001074 designated cpu.
1075
1076 Say N if unsure.
1077
Dhaval Giani7c941432010-01-20 13:26:18 +01001078menuconfig CGROUP_SCHED
1079 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001080 default n
1081 help
1082 This feature lets CPU scheduler recognize task groups and control CPU
1083 bandwidth allocation to such task groups. It uses cgroups to group
1084 tasks.
1085
1086if CGROUP_SCHED
1087config FAIR_GROUP_SCHED
1088 bool "Group scheduling for SCHED_OTHER"
1089 depends on CGROUP_SCHED
1090 default CGROUP_SCHED
1091
Paul Turnerab84d312011-07-21 09:43:28 -07001092config CFS_BANDWIDTH
1093 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001094 depends on FAIR_GROUP_SCHED
1095 default n
1096 help
1097 This option allows users to define CPU bandwidth rates (limits) for
1098 tasks running within the fair group scheduler. Groups with no limit
1099 set are considered to be unconstrained and will run with no
1100 restriction.
1101 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1102
Dhaval Giani7c941432010-01-20 13:26:18 +01001103config RT_GROUP_SCHED
1104 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001105 depends on CGROUP_SCHED
1106 default n
1107 help
1108 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001109 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001110 schedule realtime tasks for non-root users until you allocate
1111 realtime bandwidth for them.
1112 See Documentation/scheduler/sched-rt-group.txt for more information.
1113
1114endif #CGROUP_SCHED
1115
Vivek Goyalafc24d42010-04-26 19:27:56 +02001116config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001117 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001118 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001119 default n
1120 ---help---
1121 Generic block IO controller cgroup interface. This is the common
1122 cgroup interface which should be used by various IO controlling
1123 policies.
1124
1125 Currently, CFQ IO scheduler uses it to recognize task groups and
1126 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001127 to such task groups. It is also used by bio throttling logic in
1128 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001129
1130 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001131 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001132 enabling proportional weight division of disk bandwidth in CFQ, set
1133 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001134 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001135
1136 See Documentation/cgroups/blkio-controller.txt for more information.
1137
1138config DEBUG_BLK_CGROUP
1139 bool "Enable Block IO controller debugging"
1140 depends on BLK_CGROUP
1141 default n
1142 ---help---
1143 Enable some debugging help. Currently it exports additional stat
1144 files in a cgroup which can be useful for debugging.
1145
Li Zefan23964d22009-01-15 13:50:58 -08001146endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001147
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001148config CHECKPOINT_RESTORE
1149 bool "Checkpoint/restore support" if EXPERT
1150 default n
1151 help
1152 Enables additional kernel features in a sake of checkpoint/restore.
1153 In particular it adds auxiliary prctl codes to setup process text,
1154 data and heap segment sizes, and a few additional /proc filesystem
1155 entries.
1156
1157 If unsure, say N here.
1158
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001159menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001160 bool "Namespaces support" if EXPERT
1161 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001162 help
1163 Provides the way to make tasks work with different objects using
1164 the same id. For example same IPC id may refer to different objects
1165 or same user id or pid may refer to different tasks when used in
1166 different namespaces.
1167
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001168if NAMESPACES
1169
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001170config UTS_NS
1171 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001172 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001173 help
1174 In this namespace tasks see different info provided with the
1175 uname() system call
1176
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001177config IPC_NS
1178 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001179 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001180 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001181 help
1182 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001183 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001184
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001185config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001186 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001187 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001188 help
1189 This allows containers, i.e. vservers, to use user namespaces
1190 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001191
1192 When user namespaces are enabled in the kernel it is
1193 recommended that the MEMCG and MEMCG_KMEM options also be
1194 enabled and that user-space use the memory control groups to
1195 limit the amount of memory a memory unprivileged users can
1196 use.
1197
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001198 If unsure, say N.
1199
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001200config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001201 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001202 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001203 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001204 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001205 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001206 pid namespaces. This is a building block of containers.
1207
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001208config NET_NS
1209 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001210 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001211 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001212 help
1213 Allow user space to create what appear to be multiple instances
1214 of the network stack.
1215
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001216endif # NAMESPACES
1217
Mike Galbraith5091faa2010-11-30 14:18:03 +01001218config SCHED_AUTOGROUP
1219 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001220 select CGROUPS
1221 select CGROUP_SCHED
1222 select FAIR_GROUP_SCHED
1223 help
1224 This option optimizes the scheduler for common desktop workloads by
1225 automatically creating and populating task groups. This separation
1226 of workloads isolates aggressive CPU burners (like build jobs) from
1227 desktop applications. Task group autogeneration is currently based
1228 upon task session.
1229
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001230config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001231 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001232 depends on SYSFS
1233 default n
1234 help
1235 This option adds code that switches the layout of the "block" class
1236 devices, to not show up in /sys/class/block/, but only in
1237 /sys/block/.
1238
1239 This switch is only active when the sysfs.deprecated=1 boot option is
1240 passed or the SYSFS_DEPRECATED_V2 option is set.
1241
1242 This option allows new kernels to run on old distributions and tools,
1243 which might get confused by /sys/class/block/. Since 2007/2008 all
1244 major distributions and tools handle this just fine.
1245
1246 Recent distributions and userspace tools after 2009/2010 depend on
1247 the existence of /sys/class/block/, and will not work with this
1248 option enabled.
1249
1250 Only if you are using a new kernel on an old distribution, you might
1251 need to say Y here.
1252
1253config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001254 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001255 default n
1256 depends on SYSFS
1257 depends on SYSFS_DEPRECATED
1258 help
1259 Enable deprecated sysfs by default.
1260
1261 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1262 option.
1263
1264 Only if you are using a new kernel on an old distribution, you might
1265 need to say Y here. Even then, odds are you would not need it
1266 enabled, you can always pass the boot option if absolutely necessary.
1267
1268config RELAY
1269 bool "Kernel->user space relay support (formerly relayfs)"
1270 help
1271 This option enables support for relay interface support in
1272 certain file systems (such as debugfs).
1273 It is designed to provide an efficient mechanism for tools and
1274 facilities to relay large amounts of data from kernel space to
1275 user space.
1276
1277 If unsure, say N.
1278
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001279config BLK_DEV_INITRD
1280 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1281 depends on BROKEN || !FRV
1282 help
1283 The initial RAM filesystem is a ramfs which is loaded by the
1284 boot loader (loadlin or lilo) and that is mounted as root
1285 before the normal boot procedure. It is typically used to
1286 load modules needed to mount the "real" root file system,
1287 etc. See <file:Documentation/initrd.txt> for details.
1288
1289 If RAM disk support (BLK_DEV_RAM) is also included, this
1290 also enables initial RAM disk (initrd) support and adds
1291 15 Kbytes (more on some other architectures) to the kernel size.
1292
1293 If unsure say Y.
1294
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001295if BLK_DEV_INITRD
1296
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001297source "usr/Kconfig"
1298
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001299endif
1300
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001301config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001302 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001303 help
1304 Enabling this option will pass "-Os" instead of "-O2" to gcc
1305 resulting in a smaller kernel.
1306
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001307 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001308
Randy Dunlap08470622006-09-30 23:28:13 -07001309config SYSCTL
1310 bool
1311
Randy Dunlapb943c462009-03-10 12:55:46 -07001312config ANON_INODES
1313 bool
1314
Mike Frysinger657a5202013-04-30 15:28:45 -07001315config HAVE_UID16
1316 bool
1317
1318config SYSCTL_EXCEPTION_TRACE
1319 bool
1320 help
1321 Enable support for /proc/sys/debug/exception-trace.
1322
1323config SYSCTL_ARCH_UNALIGN_NO_WARN
1324 bool
1325 help
1326 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1327 Allows arch to define/use @no_unaligned_warning to possibly warn
1328 about unaligned access emulation going on under the hood.
1329
1330config SYSCTL_ARCH_UNALIGN_ALLOW
1331 bool
1332 help
1333 Enable support for /proc/sys/kernel/unaligned-trap
1334 Allows arches to define/use @unaligned_enabled to runtime toggle
1335 the unaligned access emulation.
1336 see arch/parisc/kernel/unaligned.c for reference
1337
Mike Frysinger657a5202013-04-30 15:28:45 -07001338config HAVE_PCSPKR_PLATFORM
1339 bool
1340
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001341# interpreter that classic socket filters depend on
1342config BPF
1343 bool
1344
David Rientjes6a108a12011-01-20 14:44:16 -08001345menuconfig EXPERT
1346 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001347 # Unhide debug options, to make the on-by-default options visible
1348 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 help
1350 This option allows certain base kernel options and settings
1351 to be disabled or tweaked. This is for specialized
1352 environments which can tolerate a "non-standard" kernel.
1353 Only use this if you really know what you are doing.
1354
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001355config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001356 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001357 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001358 default y
1359 help
1360 This enables the legacy 16-bit UID syscall wrappers.
1361
Fabian Frederickf6187762014-06-04 16:11:12 -07001362config SGETMASK_SYSCALL
1363 bool "sgetmask/ssetmask syscalls support" if EXPERT
1364 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1365 ---help---
1366 sys_sgetmask and sys_ssetmask are obsolete system calls
1367 no longer supported in libc but still enabled by default in some
1368 architectures.
1369
1370 If unsure, leave the default option here.
1371
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001372config SYSFS_SYSCALL
1373 bool "Sysfs syscall support" if EXPERT
1374 default y
1375 ---help---
1376 sys_sysfs is an obsolete system call no longer supported in libc.
1377 Note that disabling this option is more secure but might break
1378 compatibility with some systems.
1379
1380 If unsure say Y here.
1381
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001382config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001383 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001384 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001385 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001386 select SYSCTL
1387 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001388 sys_sysctl uses binary paths that have been found challenging
1389 to properly maintain and use. The interface in /proc/sys
1390 using paths with ascii names is now the primary path to this
1391 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001392
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001393 Almost nothing using the binary sysctl interface so if you are
1394 trying to save some space it is probably safe to disable this,
1395 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001396
WANG Congc736de62011-11-02 13:39:25 -07001397 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001398
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001400 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 default y
1402 help
1403 Say Y here to let the kernel print out symbolic crash information and
1404 symbolic stack backtraces. This increases the size of the kernel
1405 somewhat, as all symbols have to be loaded into the kernel image.
1406
1407config KALLSYMS_ALL
1408 bool "Include all symbols in kallsyms"
1409 depends on DEBUG_KERNEL && KALLSYMS
1410 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001411 Normally kallsyms only contains the symbols of functions for nicer
1412 OOPS messages and backtraces (i.e., symbols from the text and inittext
1413 sections). This is sufficient for most cases. And only in very rare
1414 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1415 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001417 This option makes sure that all symbols are loaded into the kernel
1418 image (i.e., symbols from all sections) in cost of increased kernel
1419 size (depending on the kernel configuration, it may be 300KiB or
1420 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001422 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001423
1424config PRINTK
1425 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001426 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001427 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001428 help
1429 This option enables normal printk support. Removing it
1430 eliminates most of the message strings from the kernel image
1431 and makes the kernel more or less silent. As this makes it
1432 very difficult to diagnose system problems, saying N here is
1433 strongly discouraged.
1434
Matt Mackallc8538a72005-05-01 08:59:01 -07001435config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001436 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001437 default y
1438 help
1439 Disabling this option eliminates support for BUG and WARN, reducing
1440 the size of your kernel image and potentially quietly ignoring
1441 numerous fatal conditions. You should only consider disabling this
1442 option for embedded systems with no facilities for reporting errors.
1443 Just say Y.
1444
Matt Mackall708e9a72006-01-08 01:05:25 -08001445config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001446 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001447 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001448 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001449 help
1450 Enable support for generating core dumps. Disabling saves about 4k.
1451
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001452
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001453config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001454 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001455 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001456 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001457 default y
1458 help
1459 This option allows to disable the internal PC-Speaker
1460 support, saving some memory.
1461
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462config BASE_FULL
1463 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001464 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465 help
1466 Disabling this option reduces the size of miscellaneous core
1467 kernel data structures. This saves memory on small machines,
1468 but may reduce performance.
1469
1470config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001471 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001473 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 help
1475 Disabling this option will cause the kernel to be built without
1476 support for "fast userspace mutexes". The resulting kernel may not
1477 run glibc-based applications correctly.
1478
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001479config HAVE_FUTEX_CMPXCHG
1480 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001481 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001482 help
1483 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1484 is implemented and always working. This removes a couple of runtime
1485 checks.
1486
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001488 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001490 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 help
1492 Disabling this option will cause the kernel to be built without
1493 support for epoll family of system calls.
1494
Davide Libenzifba2afa2007-05-10 22:23:13 -07001495config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001496 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001497 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001498 default y
1499 help
1500 Enable the signalfd() system call that allows to receive signals
1501 on a file descriptor.
1502
1503 If unsure, say Y.
1504
Davide Libenzib215e282007-05-10 22:23:16 -07001505config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001506 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001507 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001508 default y
1509 help
1510 Enable the timerfd() system call that allows to receive timer
1511 events on a file descriptor.
1512
1513 If unsure, say Y.
1514
Davide Libenzie1ad7462007-05-10 22:23:19 -07001515config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001516 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001517 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001518 default y
1519 help
1520 Enable the eventfd() system call that allows to receive both
1521 kernel notification (ie. KAIO) or userspace notifications.
1522
1523 If unsure, say Y.
1524
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001525# syscall, maps, verifier
1526config BPF_SYSCALL
1527 bool "Enable bpf() system call" if EXPERT
1528 select ANON_INODES
1529 select BPF
1530 default n
1531 help
1532 Enable the bpf() system call that allows to manipulate eBPF
1533 programs and maps via file descriptors.
1534
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001536 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537 default y
1538 depends on MMU
1539 help
1540 The shmem is an internal filesystem used to manage shared memory.
1541 It is backed by swap and manages resource limits. It is also exported
1542 to userspace as tmpfs if TMPFS is enabled. Disabling this
1543 option replaces shmem and tmpfs with the much simpler ramfs code,
1544 which may be appropriate on small systems without swap.
1545
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001546config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001547 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001548 default y
1549 help
1550 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001551 by some high performance threaded applications. Disabling
1552 this option saves about 7k.
1553
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001554config ADVISE_SYSCALLS
1555 bool "Enable madvise/fadvise syscalls" if EXPERT
1556 default y
1557 help
1558 This option enables the madvise and fadvise syscalls, used by
1559 applications to advise the kernel about their future memory or file
1560 usage, improving performance. If building an embedded system where no
1561 applications use these syscalls, you can disable this option to save
1562 space.
1563
Mike Frysinger657a5202013-04-30 15:28:45 -07001564config PCI_QUIRKS
1565 default y
1566 bool "Enable PCI quirk workarounds" if EXPERT
1567 depends on PCI
1568 help
1569 This enables workarounds for various PCI chipset
1570 bugs/quirks. Disable this only if your target machine is
1571 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001572
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001573config EMBEDDED
1574 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001575 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001576 select EXPERT
1577 help
1578 This option should be enabled if compiling the kernel for
1579 an embedded system so certain expert options are available
1580 for configuration.
1581
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001582config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001583 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001584 help
1585 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001586
Peter Zijlstra906010b2009-09-21 16:08:49 +02001587config PERF_USE_VMALLOC
1588 bool
1589 help
1590 See tools/perf/design.txt for details
1591
Ingo Molnar57c0c152009-09-21 12:20:38 +02001592menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001593
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001594config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001595 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001596 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001597 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001598 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001599 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001600 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001601 Enable kernel support for various performance events provided
1602 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001603
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001604 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001605 use of generic tracepoints.
1606
1607 Most modern CPUs support performance events via performance
1608 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001609 types of hw events: such as instructions executed, cachemisses
1610 suffered, or branches mis-predicted - without slowing down the
1611 kernel or applications. These registers can also trigger interrupts
1612 when a threshold number of events have passed - and can thus be
1613 used to profile the code that runs on that CPU.
1614
Ingo Molnar57c0c152009-09-21 12:20:38 +02001615 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001616 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001617 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001618 provides per task and per CPU counters, and it provides event
1619 capabilities on top of those.
1620
1621 Say Y if unsure.
1622
Peter Zijlstra906010b2009-09-21 16:08:49 +02001623config DEBUG_PERF_USE_VMALLOC
1624 default n
1625 bool "Debug: use vmalloc to back perf mmap() buffers"
1626 depends on PERF_EVENTS && DEBUG_KERNEL
1627 select PERF_USE_VMALLOC
1628 help
1629 Use vmalloc memory to back perf mmap() buffers.
1630
1631 Mostly useful for debugging the vmalloc code on platforms
1632 that don't require it.
1633
1634 Say N if unsure.
1635
Thomas Gleixner0793a612008-12-04 20:12:29 +01001636endmenu
1637
Christoph Lameterf8891e52006-06-30 01:55:45 -07001638config VM_EVENT_COUNTERS
1639 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001640 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001641 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001642 VM event counters are needed for event counts to be shown.
1643 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001644 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001645 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001646
Christoph Lameter41ecc552007-05-09 02:32:44 -07001647config SLUB_DEBUG
1648 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001649 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001650 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001651 help
1652 SLUB has extensive debug support features. Disabling these can
1653 result in significant savings in code size. This also disables
1654 SLUB sysfs support. /sys/slab will not exist and there will be
1655 no support for cache validation etc.
1656
Randy Dunlapb943c462009-03-10 12:55:46 -07001657config COMPAT_BRK
1658 bool "Disable heap randomization"
1659 default y
1660 help
1661 Randomizing heap placement makes heap exploits harder, but it
1662 also breaks ancient binaries (including anything libc5 based).
1663 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001664 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001665 /proc/sys/kernel/randomize_va_space to 2.
1666
1667 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1668
Christoph Lameter81819f02007-05-06 14:49:36 -07001669choice
1670 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001671 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001672 help
1673 This option allows to select a slab allocator.
1674
1675config SLAB
1676 bool "SLAB"
1677 help
1678 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001679 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001680 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001681
1682config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001683 bool "SLUB (Unqueued Allocator)"
1684 help
1685 SLUB is a slab allocator that minimizes cache line usage
1686 instead of managing queues of cached objects (SLAB approach).
1687 Per cpu caching is realized using slabs of objects instead
1688 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001689 and has enhanced diagnostics. SLUB is the default choice for
1690 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001691
1692config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001693 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001694 bool "SLOB (Simple Allocator)"
1695 help
Matt Mackall37291452008-02-04 22:29:38 -08001696 SLOB replaces the stock allocator with a drastically simpler
1697 allocator. SLOB is generally more space efficient but
1698 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001699
1700endchoice
1701
Joonsoo Kim345c9052013-06-19 14:05:52 +09001702config SLUB_CPU_PARTIAL
1703 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001704 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001705 bool "SLUB per cpu partial cache"
1706 help
1707 Per cpu partial caches accellerate objects allocation and freeing
1708 that is local to a processor at the price of more indeterminism
1709 in the latency of the free. On overflow these caches will be cleared
1710 which requires the taking of locks that may cause latency spikes.
1711 Typically one would choose no for a realtime system.
1712
Jie Zhangea637632009-12-14 18:00:02 -08001713config MMAP_ALLOW_UNINITIALIZED
1714 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001715 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001716 default n
1717 help
1718 Normally, and according to the Linux spec, anonymous memory obtained
1719 from mmap() has it's contents cleared before it is passed to
1720 userspace. Enabling this config option allows you to request that
1721 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1722 providing a huge performance boost. If this option is not enabled,
1723 then the flag will be ignored.
1724
1725 This is taken advantage of by uClibc's malloc(), and also by
1726 ELF-FDPIC binfmt's brk and stack allocator.
1727
1728 Because of the obvious security issues, this option should only be
1729 enabled on embedded devices where you control what is run in
1730 userspace. Since that isn't generally a problem on no-MMU systems,
1731 it is normally safe to say Y here.
1732
1733 See Documentation/nommu-mmap.txt for more information.
1734
Peter Foley82c04ff2014-04-18 15:07:11 -07001735config SYSTEM_TRUSTED_KEYRING
1736 bool "Provide system-wide ring of trusted keys"
1737 depends on KEYS
1738 help
1739 Provide a system keyring to which trusted keys can be added. Keys in
1740 the keyring are considered to be trusted. Keys may be added at will
1741 by the kernel from compiled-in data and from hardware key stores, but
1742 userspace may only add extra keys if those keys can be verified by
1743 keys already in the keyring.
1744
1745 Keys in this keyring are used by module signature checking.
1746
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001747config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001748 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001749 help
1750 Say Y here to enable the extended profiling support mechanisms used
1751 by profilers such as OProfile.
1752
Ingo Molnar5f87f112008-07-23 14:15:22 +02001753#
1754# Place an empty function call at each tracepoint site. Can be
1755# dynamically changed for a probe function.
1756#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001757config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001758 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001759
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001760source "arch/Kconfig"
1761
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762endmenu # General setup
1763
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001764config HAVE_GENERIC_DMA_COHERENT
1765 bool
1766 default n
1767
Linus Torvalds158a9622008-01-02 13:04:48 -08001768config SLABINFO
1769 bool
1770 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001771 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001772 default y
1773
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001774config RT_MUTEXES
1775 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001776
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777config BASE_SMALL
1778 int
1779 default 0 if BASE_FULL
1780 default 1 if !BASE_FULL
1781
Jan Engelhardt66da5732007-07-15 23:39:29 -07001782menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001784 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 help
1786 Kernel modules are small pieces of compiled code which can
1787 be inserted in the running kernel, rather than being
1788 permanently built into the kernel. You use the "modprobe"
1789 tool to add (and sometimes remove) them. If you say Y here,
1790 many parts of the kernel can be built as modules (by
1791 answering M instead of Y where indicated): this is most
1792 useful for infrequently used options which are not required
1793 for booting. For more information, see the man pages for
1794 modprobe, lsmod, modinfo, insmod and rmmod.
1795
1796 If you say Y here, you will need to run "make
1797 modules_install" to put the modules under /lib/modules/
1798 where modprobe can find them (you may need to be root to do
1799 this).
1800
1801 If unsure, say Y.
1802
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001803if MODULES
1804
Linus Torvalds826e4502008-05-04 17:04:16 -07001805config MODULE_FORCE_LOAD
1806 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001807 default n
1808 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001809 Allow loading of modules without version information (ie. modprobe
1810 --force). Forced module loading sets the 'F' (forced) taint flag and
1811 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001812
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813config MODULE_UNLOAD
1814 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 help
1816 Without this option you will not be able to unload any
1817 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001818 anyway), which makes your kernel smaller, faster
1819 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820
1821config MODULE_FORCE_UNLOAD
1822 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001823 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 help
1825 This option allows you to force a module to unload, even if the
1826 kernel believes it is unsafe: the kernel will remove the module
1827 without waiting for anyone to stop using it (using the -f option to
1828 rmmod). This is mainly for kernel developers and desperate users.
1829 If unsure, say N.
1830
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001832 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 help
1834 Usually, you have to use modules compiled with your kernel.
1835 Saying Y here makes it sometimes possible to use modules
1836 compiled for different kernels, by adding enough information
1837 to the modules to (hopefully) spot any changes which would
1838 make them incompatible with the kernel you are running. If
1839 unsure, say N.
1840
1841config MODULE_SRCVERSION_ALL
1842 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 help
1844 Modules which contain a MODULE_VERSION get an extra "srcversion"
1845 field inserted into their modinfo section, which contains a
1846 sum of the source files which made it. This helps maintainers
1847 see exactly which source was used to build a module (since
1848 others sometimes change the module source without updating
1849 the version). With this option, such a "srcversion" field
1850 will be created for all modules. If unsure, say N.
1851
Rusty Russell106a4ee2012-09-26 10:09:40 +01001852config MODULE_SIG
1853 bool "Module signature verification"
1854 depends on MODULES
David Howellsb56e5a12013-08-30 16:07:30 +01001855 select SYSTEM_TRUSTED_KEYRING
David Howells48ba2462012-09-26 10:11:03 +01001856 select KEYS
1857 select CRYPTO
1858 select ASYMMETRIC_KEY_TYPE
1859 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1860 select PUBLIC_KEY_ALGO_RSA
1861 select ASN1
1862 select OID_REGISTRY
1863 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001864 help
1865 Check modules for valid signatures upon load: the signature
1866 is simply appended to the module. For more information see
1867 Documentation/module-signing.txt.
1868
David Howellsea0b6dc2012-09-26 10:09:50 +01001869 !!!WARNING!!! If you enable this option, you MUST make sure that the
1870 module DOES NOT get stripped after being signed. This includes the
1871 debuginfo strip done by some packagers (such as rpmbuild) and
1872 inclusion into an initramfs that wants the module size reduced.
1873
Rusty Russell106a4ee2012-09-26 10:09:40 +01001874config MODULE_SIG_FORCE
1875 bool "Require modules to be validly signed"
1876 depends on MODULE_SIG
1877 help
1878 Reject unsigned modules or signed modules for which we don't have a
1879 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001880
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301881config MODULE_SIG_ALL
1882 bool "Automatically sign all modules"
1883 default y
1884 depends on MODULE_SIG
1885 help
1886 Sign all modules during make modules_install. Without this option,
1887 modules must be signed manually, using the scripts/sign-file tool.
1888
1889comment "Do not forget to sign required modules with scripts/sign-file"
1890 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1891
David Howellsea0b6dc2012-09-26 10:09:50 +01001892choice
1893 prompt "Which hash algorithm should modules be signed with?"
1894 depends on MODULE_SIG
1895 help
1896 This determines which sort of hashing algorithm will be used during
1897 signature generation. This algorithm _must_ be built into the kernel
1898 directly so that signature verification can take place. It is not
1899 possible to load a signed module containing the algorithm to check
1900 the signature on that module.
1901
1902config MODULE_SIG_SHA1
1903 bool "Sign modules with SHA-1"
1904 select CRYPTO_SHA1
1905
1906config MODULE_SIG_SHA224
1907 bool "Sign modules with SHA-224"
1908 select CRYPTO_SHA256
1909
1910config MODULE_SIG_SHA256
1911 bool "Sign modules with SHA-256"
1912 select CRYPTO_SHA256
1913
1914config MODULE_SIG_SHA384
1915 bool "Sign modules with SHA-384"
1916 select CRYPTO_SHA512
1917
1918config MODULE_SIG_SHA512
1919 bool "Sign modules with SHA-512"
1920 select CRYPTO_SHA512
1921
1922endchoice
1923
Michal Marek22753672013-01-25 13:41:00 +10301924config MODULE_SIG_HASH
1925 string
1926 depends on MODULE_SIG
1927 default "sha1" if MODULE_SIG_SHA1
1928 default "sha224" if MODULE_SIG_SHA224
1929 default "sha256" if MODULE_SIG_SHA256
1930 default "sha384" if MODULE_SIG_SHA384
1931 default "sha512" if MODULE_SIG_SHA512
1932
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301933config MODULE_COMPRESS
1934 bool "Compress modules on installation"
1935 depends on MODULES
1936 help
1937 This option compresses the kernel modules when 'make
1938 modules_install' is run.
1939
1940 The modules will be compressed either using gzip or xz depend on the
1941 choice made in "Compression algorithm".
1942
1943 module-init-tools has support for gzip format while kmod handle gzip
1944 and xz compressed modules.
1945
1946 When a kernel module is installed from outside of the main kernel
1947 source and uses the Kbuild system for installing modules then that
1948 kernel module will also be compressed when it is installed.
1949
1950 This option provides little benefit when the modules are to be used inside
1951 an initrd or initramfs, it generally is more efficient to compress the whole
1952 initrd or initramfs instead.
1953
1954 This is fully compatible with signed modules while the signed module is
1955 compressed. module-init-tools or kmod handles decompression and provide to
1956 other layer the uncompressed but signed payload.
1957
1958choice
1959 prompt "Compression algorithm"
1960 depends on MODULE_COMPRESS
1961 default MODULE_COMPRESS_GZIP
1962 help
1963 This determines which sort of compression will be used during
1964 'make modules_install'.
1965
1966 GZIP (default) and XZ are supported.
1967
1968config MODULE_COMPRESS_GZIP
1969 bool "GZIP"
1970
1971config MODULE_COMPRESS_XZ
1972 bool "XZ"
1973
1974endchoice
1975
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001976endif # MODULES
1977
Rusty Russell98a79d62008-12-13 21:19:41 +10301978config INIT_ALL_POSSIBLE
1979 bool
1980 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301981 Back when each arch used to define their own cpu_online_mask and
1982 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301983 with all 1s, and others with all 0s. When they were centralised,
1984 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001985 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301986
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987config STOP_MACHINE
1988 bool
1989 default y
1990 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1991 help
1992 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001993
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001994source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001995
1996config PREEMPT_NOTIFIERS
1997 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001998
Steffen Klassert16295be2010-01-06 19:47:10 +11001999config PADATA
2000 depends on SMP
2001 bool
2002
Andi Kleen754b7b62012-10-04 17:11:27 -07002003# Can be selected by architectures with broken toolchains
2004# that get confused by correct const<->read_only section
2005# mappings
2006config BROKEN_RODATA
2007 bool
2008
David Howells4520c6a2012-09-21 23:31:13 +01002009config ASN1
2010 tristate
2011 help
2012 Build a simple ASN.1 grammar compiler that produces a bytecode output
2013 that can be interpreted by the ASN.1 stream decoder and used to
2014 inform it as to what tags are to be expected in a stream and what
2015 functions to call on what tags.
2016
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002017source "kernel/Kconfig.locks"