blob: a9b4c85c036b3910c2fb33604aac43a0b5e999c6 [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
Paul Moorecb74ed22016-01-13 09:18:55 -0500302 logging of avc messages output). System call auditing is included
303 on architectures which support it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900305config HAVE_ARCH_AUDITSYSCALL
306 bool
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308config AUDITSYSCALL
Paul Moorecb74ed22016-01-13 09:18:55 -0500309 def_bool y
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
Eric Paris939a67f2009-12-17 20:12:06 -0500312config AUDIT_WATCH
313 def_bool y
314 depends on AUDITSYSCALL
315 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Al Viro74c3cbe2007-07-22 08:04:18 -0400317config AUDIT_TREE
318 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400319 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500320 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400321
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000322source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200323source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000324
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200325menu "CPU/Task time and stats accounting"
326
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200327config VIRT_CPU_ACCOUNTING
328 bool
329
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200330choice
331 prompt "Cputime accounting"
332 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100333 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200334
335# Kind of a stub config for the pure tick based cputime accounting
336config TICK_CPU_ACCOUNTING
337 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200338 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200339 help
340 This is the basic tick based cputime accounting that maintains
341 statistics about user, system and idle time spent on per jiffies
342 granularity.
343
344 If unsure, say Y.
345
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200346config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200347 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200348 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200349 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200350 help
351 Select this option to enable more accurate task and CPU time
352 accounting. This is done by reading a CPU counter on each
353 kernel entry and exit and on transitions within the kernel
354 between system, softirq and hardirq state, so there is a
355 small performance impact. In the case of s390 or IBM POWER > 5,
356 this also enables accounting of stolen time on logically-partitioned
357 systems.
358
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200359config VIRT_CPU_ACCOUNTING_GEN
360 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700361 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700362 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200363 select VIRT_CPU_ACCOUNTING
364 select CONTEXT_TRACKING
365 help
366 Select this option to enable task and CPU time accounting on full
367 dynticks systems. This accounting is implemented by watching every
368 kernel-user boundaries using the context tracking subsystem.
369 The accounting is thus performed at the expense of some significant
370 overhead.
371
372 For now this is only useful if you are working on the full
373 dynticks subsystem development.
374
375 If unsure, say N.
376
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200377config IRQ_TIME_ACCOUNTING
378 bool "Fine granularity task level IRQ time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200379 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200380 help
381 Select this option to enable fine granularity task irq time
382 accounting. This is done by reading a timestamp on each
383 transitions between softirq and hardirq state, so there can be a
384 small performance impact.
385
386 If in doubt, say N here.
387
388endchoice
389
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200390config BSD_PROCESS_ACCT
391 bool "BSD Process Accounting"
Iulia Manda28138932015-04-15 16:16:41 -0700392 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200393 help
394 If you say Y here, a user level program will be able to instruct the
395 kernel (via a special system call) to write process accounting
396 information to a file: whenever a process exits, information about
397 that process will be appended to the file by the kernel. The
398 information includes things such as creation time, owning user,
399 command name, memory usage, controlling terminal etc. (the complete
400 list is in the struct acct in <file:include/linux/acct.h>). It is
401 up to the user level program to do useful things with this
402 information. This is generally a good idea, so say Y.
403
404config BSD_PROCESS_ACCT_V3
405 bool "BSD Process Accounting version 3 file format"
406 depends on BSD_PROCESS_ACCT
407 default n
408 help
409 If you say Y here, the process accounting information is written
410 in a new file format that also logs the process IDs of each
411 process and it's parent. Note that this file format is incompatible
412 with previous v0/v1/v2 file formats, so you will need updated tools
413 for processing it. A preliminary version of these tools is available
414 at <http://www.gnu.org/software/acct/>.
415
416config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700417 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200418 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700419 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200420 default n
421 help
422 Export selected statistics for tasks/processes through the
423 generic netlink interface. Unlike BSD process accounting, the
424 statistics are available during the lifetime of tasks/processes as
425 responses to commands. Like BSD accounting, they are sent to user
426 space on task exit.
427
428 Say N if unsure.
429
430config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700431 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200432 depends on TASKSTATS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530433 select SCHED_INFO
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200434 help
435 Collect information on time spent by a task waiting for system
436 resources like cpu, synchronous block I/O completion and swapping
437 in pages. Such statistics can help in setting a task's priorities
438 relative to other tasks for cpu, io, rss limits etc.
439
440 Say N if unsure.
441
442config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700443 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200444 depends on TASKSTATS
445 help
446 Collect extended task accounting data and send the data
447 to userland for processing over the taskstats interface.
448
449 Say N if unsure.
450
451config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700452 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200453 depends on TASK_XACCT
454 help
455 Collect information on the number of bytes of storage I/O which this
456 task has caused.
457
458 Say N if unsure.
459
460endmenu # "CPU/Task time and stats accounting"
461
Mike Travisc903ff82009-01-15 12:28:29 -0800462menu "RCU Subsystem"
463
Mike Travisc903ff82009-01-15 12:28:29 -0800464config TREE_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400465 bool
466 default y if !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800467 help
468 This option selects the RCU implementation that is
469 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700470 thousands of CPUs. It also scales down nicely to
471 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800472
Pranith Kumar28f65692014-09-22 14:00:48 -0400473config PREEMPT_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400474 bool
475 default y if PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700476 help
477 This option selects the RCU implementation that is
478 designed for very large SMP systems with hundreds or
479 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700480 is also required. It also scales down nicely to
481 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700482
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800483 Select this option if you are unsure.
484
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700485config TINY_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400486 bool
487 default y if !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700488 help
489 This option selects the RCU implementation that is
490 designed for UP systems from which real-time response
491 is not required. This option greatly reduces the
492 memory footprint of RCU.
493
Paul E. McKenney78cae102015-04-20 12:19:45 -0700494config RCU_EXPERT
495 bool "Make expert-level adjustments to RCU configuration"
496 default n
497 help
498 This option needs to be enabled if you wish to make
499 expert-level adjustments to RCU configuration. By default,
500 no such adjustments can be made, which has the often-beneficial
501 side-effect of preventing "make oldconfig" from asking you all
502 sorts of detailed questions about how you would like numerous
503 obscure RCU options to be set up.
504
505 Say Y if you need to make expert-level adjustments to RCU.
506
507 Say N if you are unsure.
508
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500509config SRCU
510 bool
511 help
512 This option selects the sleepable version of RCU. This version
513 permits arbitrary sleeping or blocking within RCU read-side critical
514 sections.
515
Paul E. McKenney8315f422014-06-27 13:42:20 -0700516config TASKS_RCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -0700517 bool
Paul E. McKenney8315f422014-06-27 13:42:20 -0700518 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500519 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700520 help
521 This option enables a task-based RCU implementation that uses
522 only voluntary context switch (not preemption!), idle, and
523 user-mode execution as quiescent states.
524
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700525config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400526 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700527 help
528 This option enables RCU CPU stall code that is common between
529 the TINY and TREE variants of RCU. The purpose is to allow
530 the tiny variants to disable RCU CPU stall warnings, while
531 making these warnings mandatory for the tree variants.
532
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100533config CONTEXT_TRACKING
534 bool
535
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100536config CONTEXT_TRACKING_FORCE
537 bool "Force context tracking"
538 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200539 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200540 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200541 The major pre-requirement for full dynticks to work is to
542 support the context tracking subsystem. But there are also
543 other dependencies to provide in order to make the full
544 dynticks working.
545
546 This option stands for testing when an arch implements the
547 context tracking backend but doesn't yet fullfill all the
548 requirements to make the full dynticks feature working.
549 Without the full dynticks, there is no way to test the support
550 for context tracking and the subsystems that rely on it: RCU
551 userspace extended quiescent state and tickless cputime
552 accounting. This option copes with the absence of the full
553 dynticks subsystem by forcing the context tracking on all
554 CPUs in the system.
555
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400556 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200557 architecture backend for the context tracking.
558
559 Say N otherwise, this option brings an overhead that you
560 don't want in production.
561
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200562
Mike Travisc903ff82009-01-15 12:28:29 -0800563config RCU_FANOUT
564 int "Tree-based hierarchical RCU fanout value"
565 range 2 64 if 64BIT
566 range 2 32 if !64BIT
Paul E. McKenney05c5df32015-04-20 14:27:43 -0700567 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Mike Travisc903ff82009-01-15 12:28:29 -0800568 default 64 if 64BIT
569 default 32 if !64BIT
570 help
571 This option controls the fanout of hierarchical implementations
572 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700573 large numbers of CPUs. This value must be at least the fourth
574 root of NR_CPUS, which allows NR_CPUS to be insanely large.
575 The default value of RCU_FANOUT should be used for production
576 systems, but if you are stress-testing the RCU implementation
577 itself, small RCU_FANOUT values allow you to test large-system
578 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800579
580 Select a specific number if testing RCU itself.
581 Take the default if unsure.
582
Paul E. McKenney8932a632012-04-19 12:20:14 -0700583config RCU_FANOUT_LEAF
584 int "Tree-based hierarchical RCU leaf-level fanout value"
Paul E. McKenney8739c5c2015-04-20 18:27:54 -0700585 range 2 64 if 64BIT
586 range 2 32 if !64BIT
Paul E. McKenney47d631a2015-04-21 09:12:13 -0700587 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Paul E. McKenney8932a632012-04-19 12:20:14 -0700588 default 16
589 help
590 This option controls the leaf-level fanout of hierarchical
591 implementations of RCU, and allows trading off cache misses
592 against lock contention. Systems that synchronize their
593 scheduling-clock interrupts for energy-efficiency reasons will
594 want the default because the smaller leaf-level fanout keeps
595 lock contention levels acceptably low. Very large systems
596 (hundreds or thousands of CPUs) will instead want to set this
597 value to the maximum value possible in order to reduce the
598 number of cache misses incurred during RCU's grace-period
599 initialization. These systems tend to run CPU-bound, and thus
600 are not helped by synchronized interrupts, and thus tend to
601 skew them, which reduces lock contention enough that large
602 leaf-level fanouts work well.
603
604 Select a specific number if testing RCU itself.
605
606 Select the maximum permissible value for large systems.
607
608 Take the default if unsure.
609
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800610config RCU_FAST_NO_HZ
611 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700612 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800613 default n
614 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800615 This option permits CPUs to enter dynticks-idle state even if
616 they have RCU callbacks queued, and prevents RCU from waking
617 these CPUs up more than roughly once every four jiffies (by
618 default, you can adjust this using the rcutree.rcu_idle_gp_delay
619 parameter), thus improving energy efficiency. On the other
620 hand, this option increases the duration of RCU grace periods,
621 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800622
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800623 Say Y if energy efficiency is critically important, and you
624 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800625
626 Say N if you are unsure.
627
Mike Travisc903ff82009-01-15 12:28:29 -0800628config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400629 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800630 select DEBUG_FS
631 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700632 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400633 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700634 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800635
Paul E. McKenney24278d12010-09-27 17:25:23 -0700636config RCU_BOOST
637 bool "Enable RCU priority boosting"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700638 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700639 default n
640 help
641 This option boosts the priority of preempted RCU readers that
642 block the current preemptible RCU grace period for too long.
643 This option also prevents heavy loads from blocking RCU
644 callback invocation for all flavors of RCU.
645
646 Say Y here if you are working with real-time apps or heavy loads
647 Say N here if you are unsure.
648
Clark Williams21871d72014-09-12 21:21:09 -0500649config RCU_KTHREAD_PRIO
650 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800651 range 1 99 if RCU_BOOST
652 range 0 99 if !RCU_BOOST
653 default 1 if RCU_BOOST
654 default 0 if !RCU_BOOST
Paul E. McKenney26730f52015-04-21 09:22:14 -0700655 depends on RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700656 help
Clark Williams21871d72014-09-12 21:21:09 -0500657 This option specifies the SCHED_FIFO priority value that will be
658 assigned to the rcuc/n and rcub/n threads and is also the value
659 used for RCU_BOOST (if enabled). If you are working with a
660 real-time application that has one or more CPU-bound threads
661 running at a real-time priority level, you should set
662 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
663 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
664 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700665 applications that do not have any CPU-bound threads.
666
667 Some real-time applications might not have a single real-time
668 thread that saturates a given CPU, but instead might have
669 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500670 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700671 a priority higher than the lowest-priority thread that is
672 conspiring to prevent the CPU from running any non-real-time
673 tasks. For example, if one thread at priority 10 and another
674 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500675 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700676 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700677
678 Specify the real-time priority, or take the default if unsure.
679
680config RCU_BOOST_DELAY
681 int "Milliseconds to delay boosting after RCU grace-period start"
682 range 0 3000
683 depends on RCU_BOOST
684 default 500
685 help
686 This option specifies the time to wait after the beginning of
687 a given grace period before priority-boosting preempted RCU
688 readers blocking that grace period. Note that any RCU reader
689 blocking an expedited RCU grace period is boosted immediately.
690
691 Accept the default if unsure.
692
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700693config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700694 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400695 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenneybe55fa22015-06-02 05:29:18 -0700696 depends on RCU_EXPERT || NO_HZ_FULL
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700697 default n
698 help
699 Use this option to reduce OS jitter for aggressive HPC or
700 real-time workloads. It can also be used to offload RCU
701 callback invocation to energy-efficient CPUs in battery-powered
702 asymmetric multiprocessors.
703
704 This option offloads callback invocation from the set of
705 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800706 For each such CPU, a kthread ("rcuox/N") will be created to
707 invoke callbacks, where the "N" is the CPU being offloaded,
708 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
709 "s" for RCU-sched. Nothing prevents this kthread from running
710 on the specified CPUs, but (1) the kthreads may be preempted
711 between each callback, and (2) affinity or cgroups can be used
712 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700713
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800714 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700715 Say N here if you are unsure.
716
Paul E. McKenney911af502013-02-11 10:23:27 -0800717choice
718 prompt "Build-forced no-CBs CPUs"
719 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200720 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800721 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700722 This option allows no-CBs CPUs (whose RCU callbacks are invoked
723 from kthreads rather than from softirq context) to be specified
724 at build time. Additional no-CBs CPUs may be specified by
725 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800726
727config RCU_NOCB_CPU_NONE
728 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800729 help
730 This option does not force any of the CPUs to be no-CBs CPUs.
731 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700732 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
733 kthreads whose names begin with "rcuo". All other CPUs will
734 invoke their own RCU callbacks in softirq context.
735
736 Select this option if you want to choose no-CBs CPUs at
737 boot time, for example, to allow testing of different no-CBs
738 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800739
740config RCU_NOCB_CPU_ZERO
741 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800742 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700743 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
744 callbacks are invoked by a per-CPU kthread whose name begins
745 with "rcuo". Additional CPUs may be designated as no-CBs
746 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
747 All other CPUs will invoke their own RCU callbacks in softirq
748 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800749
750 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700751 or energy-efficiency reasons, but the real reason it exists
752 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800753
754config RCU_NOCB_CPU_ALL
755 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800756 help
757 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700758 boot parameter will be ignored. All CPUs' RCU callbacks will
759 be executed in the context of per-CPU rcuo kthreads created for
760 this purpose. Assuming that the kthreads whose names start with
761 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
762 on the remaining CPUs, but might decrease memory locality during
763 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800764
765 Select this if all CPUs need to be no-CBs CPUs for real-time
766 or energy-efficiency reasons.
767
768endchoice
769
Paul E. McKenneyee425712015-02-19 10:51:32 -0800770config RCU_EXPEDITE_BOOT
771 bool
772 default n
773 help
774 This option enables expedited grace periods at boot time,
775 as if rcu_expedite_gp() had been invoked early in boot.
776 The corresponding rcu_unexpedite_gp() is invoked from
777 rcu_end_inkernel_boot(), which is intended to be invoked
778 at the end of the kernel-only boot sequence, just before
779 init is exec'ed.
780
781 Accept the default if unsure.
782
Mike Travisc903ff82009-01-15 12:28:29 -0800783endmenu # "RCU Subsystem"
784
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700785config BUILD_BIN2C
786 bool
787 default n
788
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700790 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700791 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 ---help---
793 This option enables the complete Linux kernel ".config" file
794 contents to be saved in the kernel. It provides documentation
795 of which kernel options are used in a running kernel or in an
796 on-disk kernel. This information can be extracted from the kernel
797 image file with the script scripts/extract-ikconfig and used as
798 input to rebuild the current kernel or to build another kernel.
799 It can also be extracted from a running kernel by reading
800 /proc/config.gz if enabled (below).
801
802config IKCONFIG_PROC
803 bool "Enable access to .config through /proc/config.gz"
804 depends on IKCONFIG && PROC_FS
805 ---help---
806 This option enables access to the kernel configuration file
807 through /proc/config.gz.
808
Alistair John Strachan794543a2007-05-08 00:31:15 -0700809config LOG_BUF_SHIFT
810 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Ingo Molnarfb39f982015-07-01 10:19:11 +0200811 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700812 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700813 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700814 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700815 Select the minimal kernel log buffer size as a power of 2.
816 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
817 parameter, see below. Any higher size also might be forced
818 by "log_buf_len" boot parameter.
819
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700820 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700821 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700822 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700823 15 => 32 KB
824 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700825 13 => 8 KB
826 12 => 4 KB
827
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700828config LOG_CPU_MAX_BUF_SHIFT
829 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700830 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700831 range 0 21
832 default 12 if !BASE_SMALL
833 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700834 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700835 help
836 This option allows to increase the default ring buffer size
837 according to the number of CPUs. The value defines the contribution
838 of each CPU as a power of 2. The used space is typically only few
839 lines however it might be much more when problems are reported,
840 e.g. backtraces.
841
842 The increased size means that a new buffer has to be allocated and
843 the original static one is unused. It makes sense only on systems
844 with more CPUs. Therefore this value is used only when the sum of
845 contributions is greater than the half of the default kernel ring
846 buffer as defined by LOG_BUF_SHIFT. The default values are set
847 so that more than 64 CPUs are needed to trigger the allocation.
848
849 Also this option is ignored when "log_buf_len" kernel parameter is
850 used as it forces an exact (power of two) size of the ring buffer.
851
852 The number of possible CPUs is used for this computation ignoring
853 hotplugging making the compuation optimal for the the worst case
854 scenerio while allowing a simple algorithm to be used from bootup.
855
856 Examples shift values and their meaning:
857 17 => 128 KB for each CPU
858 16 => 64 KB for each CPU
859 15 => 32 KB for each CPU
860 14 => 16 KB for each CPU
861 13 => 8 KB for each CPU
862 12 => 4 KB for each CPU
863
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800864#
865# Architectures with an unreliable sched_clock() should select this:
866#
867config HAVE_UNSTABLE_SCHED_CLOCK
868 bool
869
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700870config GENERIC_SCHED_CLOCK
871 bool
872
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200873#
874# For architectures that want to enable the support for NUMA-affine scheduler
875# balancing logic:
876#
877config ARCH_SUPPORTS_NUMA_BALANCING
878 bool
879
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100880#
Mel Gorman72b252a2015-09-04 15:47:32 -0700881# For architectures that prefer to flush all TLBs after a number of pages
882# are unmapped instead of sending one IPI per page to flush. The architecture
883# must provide guarantees on what happens if a clean TLB cache entry is
884# written after the unmap. Details are in mm/rmap.c near the check for
885# should_defer_flush. The architecture should also consider if the full flush
886# and the refill costs are offset by the savings of sending fewer IPIs.
887config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
888 bool
889
890#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100891# For architectures that know their GCC __int128 support is sound
892#
893config ARCH_SUPPORTS_INT128
894 bool
895
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200896# For architectures that (ab)use NUMA to represent different memory regions
897# all cpu-local but of different latencies, such as SuperH.
898#
899config ARCH_WANT_NUMA_VARIABLE_LOCALITY
900 bool
901
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200902config NUMA_BALANCING
903 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904 depends on ARCH_SUPPORTS_NUMA_BALANCING
905 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
906 depends on SMP && NUMA && MIGRATION
907 help
908 This option adds support for automatic NUMA aware memory/task placement.
909 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400910 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200911
912 This system will be inactive on UMA systems.
913
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800914config NUMA_BALANCING_DEFAULT_ENABLED
915 bool "Automatically enable NUMA aware memory/task placement"
916 default y
917 depends on NUMA_BALANCING
918 help
919 If set, automatic NUMA balancing will be enabled if running on a NUMA
920 machine.
921
Li Zefan23964d22009-01-15 13:50:58 -0800922menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500923 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500924 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700925 help
Li Zefan23964d22009-01-15 13:50:58 -0800926 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800927 use with process control subsystems such as Cpusets, CFS, memory
928 controls or device isolation.
929 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800930 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800931 - Documentation/cgroups/ (features for grouping, isolation
932 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700933
934 Say N if unsure.
935
Li Zefan23964d22009-01-15 13:50:58 -0800936if CGROUPS
937
Paul Menage006cb992007-10-18 23:39:43 -0700938config CGROUP_DEBUG
939 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700940 default n
Paul Menage006cb992007-10-18 23:39:43 -0700941 help
942 This option enables a simple cgroup subsystem that
943 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800944 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700945
Li Zefan23964d22009-01-15 13:50:58 -0800946 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700947
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700948config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800949 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800950 help
951 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700952 cgroup.
953
Aleksa Sarai49b786e2015-06-09 21:32:10 +1000954config CGROUP_PIDS
955 bool "PIDs cgroup subsystem"
956 help
957 Provides enforcement of process number limits in the scope of a
958 cgroup. Any attempt to fork more processes than is allowed in the
959 cgroup will fail. PIDs are fundamentally a global resource because it
960 is fairly trivial to reach PID exhaustion before you reach even a
961 conservative kmemcg limit. As a result, it is possible to grind a
962 system to halt without being limited by other cgroup policies. The
963 PIDs cgroup subsystem is designed to stop this from happening.
964
965 It should be noted that organisational operations (such as attaching
966 to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
967 since the PIDs limit only affects a process's ability to fork, not to
968 attach to a cgroup.
969
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700970config CGROUP_DEVICE
971 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700972 help
973 Provides a cgroup implementing whitelists for devices which
974 a process in the cgroup can mknod or open.
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976config CPUSETS
977 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700979 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 allow dynamically partitioning a system into sets of CPUs and
981 Memory Nodes and assigning tasks to run only within those sets.
982 This is primarily useful on large SMP or NUMA systems.
983
984 Say N if unsure.
985
Li Zefan23964d22009-01-15 13:50:58 -0800986config PROC_PID_CPUSET
987 bool "Include legacy /proc/<pid>/cpuset file"
988 depends on CPUSETS
989 default y
990
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100991config CGROUP_CPUACCT
992 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100993 help
994 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800995 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100996
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800997config PAGE_COUNTER
998 bool
999
Andrew Mortonc255a452012-07-31 16:43:02 -07001000config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -08001001 bool "Memory Resource Controller for Control Groups"
Johannes Weiner3e32cb22014-12-10 15:42:31 -08001002 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -05001003 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -08001004 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -07001005 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +01001006 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -08001007
Andrew Mortonc255a452012-07-31 16:43:02 -07001008config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -07001009 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -07001010 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001011 help
1012 Add swap management feature to memory resource controller. When you
1013 enable this, you can limit mem+swap usage per cgroup. In other words,
1014 when you disable this, memory resource controller has no cares to
1015 usage of swap...a process can exhaust all of the swap. This extension
1016 is useful when you want to avoid exhaustion swap but this itself
1017 adds more overheads and consumes memory for remembering information.
1018 Especially if you use 32bit system or small memory system, please
1019 be careful about enabling this. When memory resource controller
1020 is disabled by boot option, this will be automatically disabled and
1021 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -07001022 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -07001023 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
1024 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -07001025config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -08001026 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -07001027 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -08001028 default y
1029 help
1030 Memory Resource Controller Swap Extension comes with its price in
1031 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -07001032 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -07001033 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -08001034 parameter should have this option unselected.
1035 For those who want to have the feature enabled by default should
1036 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -07001037 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -07001038config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -07001039 bool "Memory Resource Controller Kernel Memory accounting"
1040 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -08001041 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +00001042 help
1043 The Kernel Memory extension for Memory Resource Controller can limit
1044 the amount of memory used by kernel objects in the system. Those are
1045 fundamentally different from the entities handled by the standard
1046 Memory Controller, which are page-based, and can be swapped. Users of
1047 the kmem extension can use it to guarantee that no group of processes
1048 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001049
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001050config CGROUP_HUGETLB
1051 bool "HugeTLB Resource Controller for Control Groups"
Johannes Weiner71f87bee2014-12-10 15:42:34 -08001052 depends on HUGETLB_PAGE
1053 select PAGE_COUNTER
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -07001054 default n
1055 help
1056 Provides a cgroup Resource Controller for HugeTLB pages.
1057 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1058 The limit is enforced during page fault. Since HugeTLB doesn't
1059 support page reclaim, enforcing the limit at page fault time implies
1060 that, the application will get SIGBUS signal if it tries to access
1061 HugeTLB pages beyond its limit. This requires the application to know
1062 beforehand how much HugeTLB pages it would require for its use. The
1063 control group is tracked in the third page lru pointer. This means
1064 that we cannot use the controller with huge page less than 3 pages.
1065
Stephane Eraniane5d13672011-02-14 11:20:01 +02001066config CGROUP_PERF
1067 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1068 depends on PERF_EVENTS && CGROUPS
1069 help
1070 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +08001071 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +02001072 designated cpu.
1073
1074 Say N if unsure.
1075
Dhaval Giani7c941432010-01-20 13:26:18 +01001076menuconfig CGROUP_SCHED
1077 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +01001078 default n
1079 help
1080 This feature lets CPU scheduler recognize task groups and control CPU
1081 bandwidth allocation to such task groups. It uses cgroups to group
1082 tasks.
1083
1084if CGROUP_SCHED
1085config FAIR_GROUP_SCHED
1086 bool "Group scheduling for SCHED_OTHER"
1087 depends on CGROUP_SCHED
1088 default CGROUP_SCHED
1089
Paul Turnerab84d312011-07-21 09:43:28 -07001090config CFS_BANDWIDTH
1091 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001092 depends on FAIR_GROUP_SCHED
1093 default n
1094 help
1095 This option allows users to define CPU bandwidth rates (limits) for
1096 tasks running within the fair group scheduler. Groups with no limit
1097 set are considered to be unconstrained and will run with no
1098 restriction.
1099 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1100
Dhaval Giani7c941432010-01-20 13:26:18 +01001101config RT_GROUP_SCHED
1102 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001103 depends on CGROUP_SCHED
1104 default n
1105 help
1106 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001107 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001108 schedule realtime tasks for non-root users until you allocate
1109 realtime bandwidth for them.
1110 See Documentation/scheduler/sched-rt-group.txt for more information.
1111
1112endif #CGROUP_SCHED
1113
Vivek Goyalafc24d42010-04-26 19:27:56 +02001114config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -08001115 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -07001116 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +02001117 default n
1118 ---help---
1119 Generic block IO controller cgroup interface. This is the common
1120 cgroup interface which should be used by various IO controlling
1121 policies.
1122
1123 Currently, CFQ IO scheduler uses it to recognize task groups and
1124 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -04001125 to such task groups. It is also used by bio throttling logic in
1126 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001127
1128 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -04001129 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +00001130 enabling proportional weight division of disk bandwidth in CFQ, set
1131 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +00001132 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001133
1134 See Documentation/cgroups/blkio-controller.txt for more information.
1135
1136config DEBUG_BLK_CGROUP
1137 bool "Enable Block IO controller debugging"
1138 depends on BLK_CGROUP
1139 default n
1140 ---help---
1141 Enable some debugging help. Currently it exports additional stat
1142 files in a cgroup which can be useful for debugging.
1143
Tejun Heo89e9b9e2015-05-22 17:13:36 -04001144config CGROUP_WRITEBACK
1145 bool
1146 depends on MEMCG && BLK_CGROUP
1147 default y
1148
Li Zefan23964d22009-01-15 13:50:58 -08001149endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001150
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001151config CHECKPOINT_RESTORE
1152 bool "Checkpoint/restore support" if EXPERT
Iago López Galeiras2e13ba52015-06-25 15:00:57 -07001153 select PROC_CHILDREN
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001154 default n
1155 help
1156 Enables additional kernel features in a sake of checkpoint/restore.
1157 In particular it adds auxiliary prctl codes to setup process text,
1158 data and heap segment sizes, and a few additional /proc filesystem
1159 entries.
1160
1161 If unsure, say N here.
1162
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001163menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001164 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001165 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001166 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001167 help
1168 Provides the way to make tasks work with different objects using
1169 the same id. For example same IPC id may refer to different objects
1170 or same user id or pid may refer to different tasks when used in
1171 different namespaces.
1172
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001173if NAMESPACES
1174
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001175config UTS_NS
1176 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001177 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001178 help
1179 In this namespace tasks see different info provided with the
1180 uname() system call
1181
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001182config IPC_NS
1183 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001184 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001185 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001186 help
1187 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001188 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001189
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001190config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001191 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001192 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001193 help
1194 This allows containers, i.e. vservers, to use user namespaces
1195 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001196
1197 When user namespaces are enabled in the kernel it is
1198 recommended that the MEMCG and MEMCG_KMEM options also be
1199 enabled and that user-space use the memory control groups to
1200 limit the amount of memory a memory unprivileged users can
1201 use.
1202
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001203 If unsure, say N.
1204
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001205config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001206 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001207 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001208 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001209 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001210 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001211 pid namespaces. This is a building block of containers.
1212
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001213config NET_NS
1214 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001215 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001216 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001217 help
1218 Allow user space to create what appear to be multiple instances
1219 of the network stack.
1220
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001221endif # NAMESPACES
1222
Mike Galbraith5091faa2010-11-30 14:18:03 +01001223config SCHED_AUTOGROUP
1224 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001225 select CGROUPS
1226 select CGROUP_SCHED
1227 select FAIR_GROUP_SCHED
1228 help
1229 This option optimizes the scheduler for common desktop workloads by
1230 automatically creating and populating task groups. This separation
1231 of workloads isolates aggressive CPU burners (like build jobs) from
1232 desktop applications. Task group autogeneration is currently based
1233 upon task session.
1234
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001235config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001236 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001237 depends on SYSFS
1238 default n
1239 help
1240 This option adds code that switches the layout of the "block" class
1241 devices, to not show up in /sys/class/block/, but only in
1242 /sys/block/.
1243
1244 This switch is only active when the sysfs.deprecated=1 boot option is
1245 passed or the SYSFS_DEPRECATED_V2 option is set.
1246
1247 This option allows new kernels to run on old distributions and tools,
1248 which might get confused by /sys/class/block/. Since 2007/2008 all
1249 major distributions and tools handle this just fine.
1250
1251 Recent distributions and userspace tools after 2009/2010 depend on
1252 the existence of /sys/class/block/, and will not work with this
1253 option enabled.
1254
1255 Only if you are using a new kernel on an old distribution, you might
1256 need to say Y here.
1257
1258config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001259 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001260 default n
1261 depends on SYSFS
1262 depends on SYSFS_DEPRECATED
1263 help
1264 Enable deprecated sysfs by default.
1265
1266 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1267 option.
1268
1269 Only if you are using a new kernel on an old distribution, you might
1270 need to say Y here. Even then, odds are you would not need it
1271 enabled, you can always pass the boot option if absolutely necessary.
1272
1273config RELAY
1274 bool "Kernel->user space relay support (formerly relayfs)"
1275 help
1276 This option enables support for relay interface support in
1277 certain file systems (such as debugfs).
1278 It is designed to provide an efficient mechanism for tools and
1279 facilities to relay large amounts of data from kernel space to
1280 user space.
1281
1282 If unsure, say N.
1283
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001284config BLK_DEV_INITRD
1285 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1286 depends on BROKEN || !FRV
1287 help
1288 The initial RAM filesystem is a ramfs which is loaded by the
1289 boot loader (loadlin or lilo) and that is mounted as root
1290 before the normal boot procedure. It is typically used to
1291 load modules needed to mount the "real" root file system,
1292 etc. See <file:Documentation/initrd.txt> for details.
1293
1294 If RAM disk support (BLK_DEV_RAM) is also included, this
1295 also enables initial RAM disk (initrd) support and adds
1296 15 Kbytes (more on some other architectures) to the kernel size.
1297
1298 If unsure say Y.
1299
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001300if BLK_DEV_INITRD
1301
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001302source "usr/Kconfig"
1303
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001304endif
1305
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001306config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001307 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001308 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001309 Enabling this option will pass "-Os" instead of "-O2" to
1310 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001311
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001312 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001313
Randy Dunlap08470622006-09-30 23:28:13 -07001314config SYSCTL
1315 bool
1316
Randy Dunlapb943c462009-03-10 12:55:46 -07001317config ANON_INODES
1318 bool
1319
Mike Frysinger657a5202013-04-30 15:28:45 -07001320config HAVE_UID16
1321 bool
1322
1323config SYSCTL_EXCEPTION_TRACE
1324 bool
1325 help
1326 Enable support for /proc/sys/debug/exception-trace.
1327
1328config SYSCTL_ARCH_UNALIGN_NO_WARN
1329 bool
1330 help
1331 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1332 Allows arch to define/use @no_unaligned_warning to possibly warn
1333 about unaligned access emulation going on under the hood.
1334
1335config SYSCTL_ARCH_UNALIGN_ALLOW
1336 bool
1337 help
1338 Enable support for /proc/sys/kernel/unaligned-trap
1339 Allows arches to define/use @unaligned_enabled to runtime toggle
1340 the unaligned access emulation.
1341 see arch/parisc/kernel/unaligned.c for reference
1342
Mike Frysinger657a5202013-04-30 15:28:45 -07001343config HAVE_PCSPKR_PLATFORM
1344 bool
1345
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001346# interpreter that classic socket filters depend on
1347config BPF
1348 bool
1349
David Rientjes6a108a12011-01-20 14:44:16 -08001350menuconfig EXPERT
1351 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001352 # Unhide debug options, to make the on-by-default options visible
1353 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 help
1355 This option allows certain base kernel options and settings
1356 to be disabled or tweaked. This is for specialized
1357 environments which can tolerate a "non-standard" kernel.
1358 Only use this if you really know what you are doing.
1359
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001360config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001361 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001362 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001363 default y
1364 help
1365 This enables the legacy 16-bit UID syscall wrappers.
1366
Iulia Manda28138932015-04-15 16:16:41 -07001367config MULTIUSER
1368 bool "Multiple users, groups and capabilities support" if EXPERT
1369 default y
1370 help
1371 This option enables support for non-root users, groups and
1372 capabilities.
1373
1374 If you say N here, all processes will run with UID 0, GID 0, and all
1375 possible capabilities. Saying N here also compiles out support for
1376 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1377 setgid, and capset.
1378
1379 If unsure, say Y here.
1380
Fabian Frederickf6187762014-06-04 16:11:12 -07001381config SGETMASK_SYSCALL
1382 bool "sgetmask/ssetmask syscalls support" if EXPERT
1383 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1384 ---help---
1385 sys_sgetmask and sys_ssetmask are obsolete system calls
1386 no longer supported in libc but still enabled by default in some
1387 architectures.
1388
1389 If unsure, leave the default option here.
1390
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001391config SYSFS_SYSCALL
1392 bool "Sysfs syscall support" if EXPERT
1393 default y
1394 ---help---
1395 sys_sysfs is an obsolete system call no longer supported in libc.
1396 Note that disabling this option is more secure but might break
1397 compatibility with some systems.
1398
1399 If unsure say Y here.
1400
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001401config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001402 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001403 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001404 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001405 select SYSCTL
1406 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001407 sys_sysctl uses binary paths that have been found challenging
1408 to properly maintain and use. The interface in /proc/sys
1409 using paths with ascii names is now the primary path to this
1410 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001411
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001412 Almost nothing using the binary sysctl interface so if you are
1413 trying to save some space it is probably safe to disable this,
1414 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001415
WANG Congc736de62011-11-02 13:39:25 -07001416 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001419 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 default y
1421 help
1422 Say Y here to let the kernel print out symbolic crash information and
1423 symbolic stack backtraces. This increases the size of the kernel
1424 somewhat, as all symbols have to be loaded into the kernel image.
1425
1426config KALLSYMS_ALL
1427 bool "Include all symbols in kallsyms"
1428 depends on DEBUG_KERNEL && KALLSYMS
1429 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001430 Normally kallsyms only contains the symbols of functions for nicer
1431 OOPS messages and backtraces (i.e., symbols from the text and inittext
1432 sections). This is sufficient for most cases. And only in very rare
1433 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1434 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001436 This option makes sure that all symbols are loaded into the kernel
1437 image (i.e., symbols from all sections) in cost of increased kernel
1438 size (depending on the kernel configuration, it may be 300KiB or
1439 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001441 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001442
1443config PRINTK
1444 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001445 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001446 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001447 help
1448 This option enables normal printk support. Removing it
1449 eliminates most of the message strings from the kernel image
1450 and makes the kernel more or less silent. As this makes it
1451 very difficult to diagnose system problems, saying N here is
1452 strongly discouraged.
1453
Matt Mackallc8538a72005-05-01 08:59:01 -07001454config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001455 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001456 default y
1457 help
1458 Disabling this option eliminates support for BUG and WARN, reducing
1459 the size of your kernel image and potentially quietly ignoring
1460 numerous fatal conditions. You should only consider disabling this
1461 option for embedded systems with no facilities for reporting errors.
1462 Just say Y.
1463
Matt Mackall708e9a72006-01-08 01:05:25 -08001464config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001465 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001466 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001467 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001468 help
1469 Enable support for generating core dumps. Disabling saves about 4k.
1470
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001471
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001472config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001473 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001474 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001475 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001476 default y
1477 help
1478 This option allows to disable the internal PC-Speaker
1479 support, saving some memory.
1480
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481config BASE_FULL
1482 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001483 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 help
1485 Disabling this option reduces the size of miscellaneous core
1486 kernel data structures. This saves memory on small machines,
1487 but may reduce performance.
1488
1489config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001490 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001492 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 help
1494 Disabling this option will cause the kernel to be built without
1495 support for "fast userspace mutexes". The resulting kernel may not
1496 run glibc-based applications correctly.
1497
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001498config HAVE_FUTEX_CMPXCHG
1499 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001500 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001501 help
1502 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1503 is implemented and always working. This removes a couple of runtime
1504 checks.
1505
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001507 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001509 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 help
1511 Disabling this option will cause the kernel to be built without
1512 support for epoll family of system calls.
1513
Davide Libenzifba2afa2007-05-10 22:23:13 -07001514config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001515 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001516 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001517 default y
1518 help
1519 Enable the signalfd() system call that allows to receive signals
1520 on a file descriptor.
1521
1522 If unsure, say Y.
1523
Davide Libenzib215e282007-05-10 22:23:16 -07001524config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001525 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001526 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001527 default y
1528 help
1529 Enable the timerfd() system call that allows to receive timer
1530 events on a file descriptor.
1531
1532 If unsure, say Y.
1533
Davide Libenzie1ad7462007-05-10 22:23:19 -07001534config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001535 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001536 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001537 default y
1538 help
1539 Enable the eventfd() system call that allows to receive both
1540 kernel notification (ie. KAIO) or userspace notifications.
1541
1542 If unsure, say Y.
1543
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001544# syscall, maps, verifier
1545config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001546 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001547 select ANON_INODES
1548 select BPF
1549 default n
1550 help
1551 Enable the bpf() system call that allows to manipulate eBPF
1552 programs and maps via file descriptors.
1553
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001555 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 default y
1557 depends on MMU
1558 help
1559 The shmem is an internal filesystem used to manage shared memory.
1560 It is backed by swap and manages resource limits. It is also exported
1561 to userspace as tmpfs if TMPFS is enabled. Disabling this
1562 option replaces shmem and tmpfs with the much simpler ramfs code,
1563 which may be appropriate on small systems without swap.
1564
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001565config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001566 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001567 default y
1568 help
1569 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001570 by some high performance threaded applications. Disabling
1571 this option saves about 7k.
1572
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001573config ADVISE_SYSCALLS
1574 bool "Enable madvise/fadvise syscalls" if EXPERT
1575 default y
1576 help
1577 This option enables the madvise and fadvise syscalls, used by
1578 applications to advise the kernel about their future memory or file
1579 usage, improving performance. If building an embedded system where no
1580 applications use these syscalls, you can disable this option to save
1581 space.
1582
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001583config USERFAULTFD
1584 bool "Enable userfaultfd() system call"
1585 select ANON_INODES
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001586 depends on MMU
1587 help
1588 Enable the userfaultfd() system call that allows to intercept and
1589 handle page faults in userland.
1590
Mike Frysinger657a5202013-04-30 15:28:45 -07001591config PCI_QUIRKS
1592 default y
1593 bool "Enable PCI quirk workarounds" if EXPERT
1594 depends on PCI
1595 help
1596 This enables workarounds for various PCI chipset
1597 bugs/quirks. Disable this only if your target machine is
1598 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001599
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001600config MEMBARRIER
1601 bool "Enable membarrier() system call" if EXPERT
1602 default y
1603 help
1604 Enable the membarrier() system call that allows issuing memory
1605 barriers across all running threads, which can be used to distribute
1606 the cost of user-space memory barriers asymmetrically by transforming
1607 pairs of memory barriers into pairs consisting of membarrier() and a
1608 compiler barrier.
1609
1610 If unsure, say Y.
1611
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001612config EMBEDDED
1613 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001614 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001615 select EXPERT
1616 help
1617 This option should be enabled if compiling the kernel for
1618 an embedded system so certain expert options are available
1619 for configuration.
1620
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001621config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001622 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001623 help
1624 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001625
Peter Zijlstra906010b2009-09-21 16:08:49 +02001626config PERF_USE_VMALLOC
1627 bool
1628 help
1629 See tools/perf/design.txt for details
1630
Ingo Molnar57c0c152009-09-21 12:20:38 +02001631menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001632
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001633config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001634 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001635 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001636 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001637 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001638 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001639 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001640 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001641 Enable kernel support for various performance events provided
1642 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001643
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001644 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001645 use of generic tracepoints.
1646
1647 Most modern CPUs support performance events via performance
1648 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001649 types of hw events: such as instructions executed, cachemisses
1650 suffered, or branches mis-predicted - without slowing down the
1651 kernel or applications. These registers can also trigger interrupts
1652 when a threshold number of events have passed - and can thus be
1653 used to profile the code that runs on that CPU.
1654
Ingo Molnar57c0c152009-09-21 12:20:38 +02001655 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001656 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001657 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001658 provides per task and per CPU counters, and it provides event
1659 capabilities on top of those.
1660
1661 Say Y if unsure.
1662
Peter Zijlstra906010b2009-09-21 16:08:49 +02001663config DEBUG_PERF_USE_VMALLOC
1664 default n
1665 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001666 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001667 select PERF_USE_VMALLOC
1668 help
1669 Use vmalloc memory to back perf mmap() buffers.
1670
1671 Mostly useful for debugging the vmalloc code on platforms
1672 that don't require it.
1673
1674 Say N if unsure.
1675
Thomas Gleixner0793a612008-12-04 20:12:29 +01001676endmenu
1677
Christoph Lameterf8891e52006-06-30 01:55:45 -07001678config VM_EVENT_COUNTERS
1679 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001680 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001681 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001682 VM event counters are needed for event counts to be shown.
1683 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001684 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001685 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001686
Christoph Lameter41ecc552007-05-09 02:32:44 -07001687config SLUB_DEBUG
1688 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001689 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001690 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001691 help
1692 SLUB has extensive debug support features. Disabling these can
1693 result in significant savings in code size. This also disables
1694 SLUB sysfs support. /sys/slab will not exist and there will be
1695 no support for cache validation etc.
1696
Randy Dunlapb943c462009-03-10 12:55:46 -07001697config COMPAT_BRK
1698 bool "Disable heap randomization"
1699 default y
1700 help
1701 Randomizing heap placement makes heap exploits harder, but it
1702 also breaks ancient binaries (including anything libc5 based).
1703 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001704 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001705 /proc/sys/kernel/randomize_va_space to 2.
1706
1707 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1708
Christoph Lameter81819f02007-05-06 14:49:36 -07001709choice
1710 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001711 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001712 help
1713 This option allows to select a slab allocator.
1714
1715config SLAB
1716 bool "SLAB"
1717 help
1718 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001719 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001720 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001721
1722config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001723 bool "SLUB (Unqueued Allocator)"
1724 help
1725 SLUB is a slab allocator that minimizes cache line usage
1726 instead of managing queues of cached objects (SLAB approach).
1727 Per cpu caching is realized using slabs of objects instead
1728 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001729 and has enhanced diagnostics. SLUB is the default choice for
1730 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001731
1732config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001733 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001734 bool "SLOB (Simple Allocator)"
1735 help
Matt Mackall37291452008-02-04 22:29:38 -08001736 SLOB replaces the stock allocator with a drastically simpler
1737 allocator. SLOB is generally more space efficient but
1738 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001739
1740endchoice
1741
Joonsoo Kim345c9052013-06-19 14:05:52 +09001742config SLUB_CPU_PARTIAL
1743 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001744 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001745 bool "SLUB per cpu partial cache"
1746 help
1747 Per cpu partial caches accellerate objects allocation and freeing
1748 that is local to a processor at the price of more indeterminism
1749 in the latency of the free. On overflow these caches will be cleared
1750 which requires the taking of locks that may cause latency spikes.
1751 Typically one would choose no for a realtime system.
1752
Jie Zhangea637632009-12-14 18:00:02 -08001753config MMAP_ALLOW_UNINITIALIZED
1754 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001755 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001756 default n
1757 help
1758 Normally, and according to the Linux spec, anonymous memory obtained
1759 from mmap() has it's contents cleared before it is passed to
1760 userspace. Enabling this config option allows you to request that
1761 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1762 providing a huge performance boost. If this option is not enabled,
1763 then the flag will be ignored.
1764
1765 This is taken advantage of by uClibc's malloc(), and also by
1766 ELF-FDPIC binfmt's brk and stack allocator.
1767
1768 Because of the obvious security issues, this option should only be
1769 enabled on embedded devices where you control what is run in
1770 userspace. Since that isn't generally a problem on no-MMU systems,
1771 it is normally safe to say Y here.
1772
1773 See Documentation/nommu-mmap.txt for more information.
1774
David Howells091f6e22015-07-20 21:16:28 +01001775config SYSTEM_DATA_VERIFICATION
1776 def_bool n
1777 select SYSTEM_TRUSTED_KEYRING
1778 select KEYS
1779 select CRYPTO
1780 select ASYMMETRIC_KEY_TYPE
1781 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1782 select PUBLIC_KEY_ALGO_RSA
1783 select ASN1
1784 select OID_REGISTRY
1785 select X509_CERTIFICATE_PARSER
1786 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001787 help
David Howells091f6e22015-07-20 21:16:28 +01001788 Provide PKCS#7 message verification using the contents of the system
1789 trusted keyring to provide public keys. This then can be used for
1790 module verification, kexec image verification and firmware blob
1791 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001792
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001793config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001794 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001795 help
1796 Say Y here to enable the extended profiling support mechanisms used
1797 by profilers such as OProfile.
1798
Ingo Molnar5f87f112008-07-23 14:15:22 +02001799#
1800# Place an empty function call at each tracepoint site. Can be
1801# dynamically changed for a probe function.
1802#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001803config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001804 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001805
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001806source "arch/Kconfig"
1807
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808endmenu # General setup
1809
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001810config HAVE_GENERIC_DMA_COHERENT
1811 bool
1812 default n
1813
Linus Torvalds158a9622008-01-02 13:04:48 -08001814config SLABINFO
1815 bool
1816 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001817 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001818 default y
1819
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001820config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001821 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001822
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823config BASE_SMALL
1824 int
1825 default 0 if BASE_FULL
1826 default 1 if !BASE_FULL
1827
Jan Engelhardt66da5732007-07-15 23:39:29 -07001828menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001830 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 help
1832 Kernel modules are small pieces of compiled code which can
1833 be inserted in the running kernel, rather than being
1834 permanently built into the kernel. You use the "modprobe"
1835 tool to add (and sometimes remove) them. If you say Y here,
1836 many parts of the kernel can be built as modules (by
1837 answering M instead of Y where indicated): this is most
1838 useful for infrequently used options which are not required
1839 for booting. For more information, see the man pages for
1840 modprobe, lsmod, modinfo, insmod and rmmod.
1841
1842 If you say Y here, you will need to run "make
1843 modules_install" to put the modules under /lib/modules/
1844 where modprobe can find them (you may need to be root to do
1845 this).
1846
1847 If unsure, say Y.
1848
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001849if MODULES
1850
Linus Torvalds826e4502008-05-04 17:04:16 -07001851config MODULE_FORCE_LOAD
1852 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001853 default n
1854 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001855 Allow loading of modules without version information (ie. modprobe
1856 --force). Forced module loading sets the 'F' (forced) taint flag and
1857 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001858
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859config MODULE_UNLOAD
1860 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 help
1862 Without this option you will not be able to unload any
1863 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001864 anyway), which makes your kernel smaller, faster
1865 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866
1867config MODULE_FORCE_UNLOAD
1868 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001869 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 help
1871 This option allows you to force a module to unload, even if the
1872 kernel believes it is unsafe: the kernel will remove the module
1873 without waiting for anyone to stop using it (using the -f option to
1874 rmmod). This is mainly for kernel developers and desperate users.
1875 If unsure, say N.
1876
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001878 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879 help
1880 Usually, you have to use modules compiled with your kernel.
1881 Saying Y here makes it sometimes possible to use modules
1882 compiled for different kernels, by adding enough information
1883 to the modules to (hopefully) spot any changes which would
1884 make them incompatible with the kernel you are running. If
1885 unsure, say N.
1886
1887config MODULE_SRCVERSION_ALL
1888 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889 help
1890 Modules which contain a MODULE_VERSION get an extra "srcversion"
1891 field inserted into their modinfo section, which contains a
1892 sum of the source files which made it. This helps maintainers
1893 see exactly which source was used to build a module (since
1894 others sometimes change the module source without updating
1895 the version). With this option, such a "srcversion" field
1896 will be created for all modules. If unsure, say N.
1897
Rusty Russell106a4ee2012-09-26 10:09:40 +01001898config MODULE_SIG
1899 bool "Module signature verification"
1900 depends on MODULES
David Howells091f6e22015-07-20 21:16:28 +01001901 select SYSTEM_DATA_VERIFICATION
Rusty Russell106a4ee2012-09-26 10:09:40 +01001902 help
1903 Check modules for valid signatures upon load: the signature
1904 is simply appended to the module. For more information see
1905 Documentation/module-signing.txt.
1906
David Howells228c37f2015-08-11 12:38:54 +01001907 Note that this option adds the OpenSSL development packages as a
1908 kernel build dependency so that the signing tool can use its crypto
1909 library.
1910
David Howellsea0b6dc2012-09-26 10:09:50 +01001911 !!!WARNING!!! If you enable this option, you MUST make sure that the
1912 module DOES NOT get stripped after being signed. This includes the
1913 debuginfo strip done by some packagers (such as rpmbuild) and
1914 inclusion into an initramfs that wants the module size reduced.
1915
Rusty Russell106a4ee2012-09-26 10:09:40 +01001916config MODULE_SIG_FORCE
1917 bool "Require modules to be validly signed"
1918 depends on MODULE_SIG
1919 help
1920 Reject unsigned modules or signed modules for which we don't have a
1921 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001922
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301923config MODULE_SIG_ALL
1924 bool "Automatically sign all modules"
1925 default y
1926 depends on MODULE_SIG
1927 help
1928 Sign all modules during make modules_install. Without this option,
1929 modules must be signed manually, using the scripts/sign-file tool.
1930
1931comment "Do not forget to sign required modules with scripts/sign-file"
1932 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1933
David Howellsea0b6dc2012-09-26 10:09:50 +01001934choice
1935 prompt "Which hash algorithm should modules be signed with?"
1936 depends on MODULE_SIG
1937 help
1938 This determines which sort of hashing algorithm will be used during
1939 signature generation. This algorithm _must_ be built into the kernel
1940 directly so that signature verification can take place. It is not
1941 possible to load a signed module containing the algorithm to check
1942 the signature on that module.
1943
1944config MODULE_SIG_SHA1
1945 bool "Sign modules with SHA-1"
1946 select CRYPTO_SHA1
1947
1948config MODULE_SIG_SHA224
1949 bool "Sign modules with SHA-224"
1950 select CRYPTO_SHA256
1951
1952config MODULE_SIG_SHA256
1953 bool "Sign modules with SHA-256"
1954 select CRYPTO_SHA256
1955
1956config MODULE_SIG_SHA384
1957 bool "Sign modules with SHA-384"
1958 select CRYPTO_SHA512
1959
1960config MODULE_SIG_SHA512
1961 bool "Sign modules with SHA-512"
1962 select CRYPTO_SHA512
1963
1964endchoice
1965
Michal Marek22753672013-01-25 13:41:00 +10301966config MODULE_SIG_HASH
1967 string
1968 depends on MODULE_SIG
1969 default "sha1" if MODULE_SIG_SHA1
1970 default "sha224" if MODULE_SIG_SHA224
1971 default "sha256" if MODULE_SIG_SHA256
1972 default "sha384" if MODULE_SIG_SHA384
1973 default "sha512" if MODULE_SIG_SHA512
1974
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301975config MODULE_COMPRESS
1976 bool "Compress modules on installation"
1977 depends on MODULES
1978 help
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301979
Rusty Russellb6c09b52015-06-16 12:16:22 +09301980 Compresses kernel modules when 'make modules_install' is run; gzip or
1981 xz depending on "Compression algorithm" below.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301982
Rusty Russellb6c09b52015-06-16 12:16:22 +09301983 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301984
Rusty Russellb6c09b52015-06-16 12:16:22 +09301985 Out-of-tree kernel modules installed using Kbuild will also be
1986 compressed upon installation.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301987
Rusty Russellb6c09b52015-06-16 12:16:22 +09301988 Note: for modules inside an initrd or initramfs, it's more efficient
1989 to compress the whole initrd or initramfs instead.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301990
Rusty Russellb6c09b52015-06-16 12:16:22 +09301991 Note: This is fully compatible with signed modules.
1992
1993 If in doubt, say N.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301994
1995choice
1996 prompt "Compression algorithm"
1997 depends on MODULE_COMPRESS
1998 default MODULE_COMPRESS_GZIP
1999 help
2000 This determines which sort of compression will be used during
2001 'make modules_install'.
2002
2003 GZIP (default) and XZ are supported.
2004
2005config MODULE_COMPRESS_GZIP
2006 bool "GZIP"
2007
2008config MODULE_COMPRESS_XZ
2009 bool "XZ"
2010
2011endchoice
2012
Robert P. J. Day0b0de142008-08-04 13:31:32 -04002013endif # MODULES
2014
Peter Zijlstra6c9692e2015-05-27 11:09:37 +09302015config MODULES_TREE_LOOKUP
2016 def_bool y
2017 depends on PERF_EVENTS || TRACING
2018
Rusty Russell98a79d62008-12-13 21:19:41 +10302019config INIT_ALL_POSSIBLE
2020 bool
2021 help
Rusty Russell5f054e32012-03-29 15:38:31 +10302022 Back when each arch used to define their own cpu_online_mask and
2023 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10302024 with all 1s, and others with all 0s. When they were centralised,
2025 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01002026 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10302027
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002028source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07002029
2030config PREEMPT_NOTIFIERS
2031 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01002032
Steffen Klassert16295be2010-01-06 19:47:10 +11002033config PADATA
2034 depends on SMP
2035 bool
2036
Andi Kleen754b7b62012-10-04 17:11:27 -07002037# Can be selected by architectures with broken toolchains
2038# that get confused by correct const<->read_only section
2039# mappings
2040config BROKEN_RODATA
2041 bool
2042
David Howells4520c6a2012-09-21 23:31:13 +01002043config ASN1
2044 tristate
2045 help
2046 Build a simple ASN.1 grammar compiler that produces a bytecode output
2047 that can be interpreted by the ASN.1 stream decoder and used to
2048 inform it as to what tags are to be expected in a stream and what
2049 functions to call on what tags.
2050
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002051source "kernel/Kconfig.locks"