blob: 66eefd9ba73c8c085485b96a2d3ea20b410045c7 [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 Oberparleiterb99b87f72009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f72009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config HAVE_IRQ_WORK
24 bool
25
26config IRQ_WORK
27 bool
28 depends on HAVE_IRQ_WORK
29
David Daney1dbdc6f2012-04-19 14:59:57 -070030config BUILDTIME_EXTABLE_SORT
31 bool
32
Al Boldiff0cfc62007-07-31 00:39:23 -070033menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35config EXPERIMENTAL
Kees Cook5a958db2012-10-02 11:36:31 -070036 bool
37 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config BROKEN
40 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42config BROKEN_ON_SMP
43 bool
44 depends on BROKEN || !SMP
45 default y
46
Linus Torvalds1da177e2005-04-16 15:20:36 -070047config INIT_ENV_ARG_LIMIT
48 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070049 default 32 if !UML
50 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 help
Randy Dunlap34ad92c22005-10-30 15:01:46 -080052 Maximum of each of the number of arguments and environment
53 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Roland McGrath84336462009-12-21 16:24:06 -080056config CROSS_COMPILE
57 string "Cross-compiler tool prefix"
58 help
59 Same as running 'make CROSS_COMPILE=prefix-' but stored for
60 default make runs in this kernel build directory. You don't
61 need to set this unless you want the configured kernel build
62 directory to select the cross-compiler automatically.
63
Linus Torvalds1da177e2005-04-16 15:20:36 -070064config LOCALVERSION
65 string "Local version - append to kernel release"
66 help
67 Append an extra string to the end of your kernel version.
68 This will show up when you type uname, for example.
69 The string you set here will be appended after the contents of
70 any files with a filename matching localversion* in your
71 object and source tree, in that order. Your total string can
72 be a maximum of 64 characters.
73
Ryan Andersonaaebf432005-07-31 04:57:49 -040074config LOCALVERSION_AUTO
75 bool "Automatically append version information to the version string"
76 default y
77 help
78 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020079 release tree by looking for git tags that belong to the current
80 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040081
82 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020083 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040084 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020085 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -040086
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020087 (The actual string used here is the first eight characters produced
88 by running the command:
89
90 $ git rev-parse --verify HEAD
91
92 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -040093
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -080094config HAVE_KERNEL_GZIP
95 bool
96
97config HAVE_KERNEL_BZIP2
98 bool
99
100config HAVE_KERNEL_LZMA
101 bool
102
Lasse Collin3ebe1242011-01-12 17:01:23 -0800103config HAVE_KERNEL_XZ
104 bool
105
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800106config HAVE_KERNEL_LZO
107 bool
108
Alain Knaff30d65db2009-01-04 22:46:17 +0100109choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800110 prompt "Kernel compression mode"
111 default KERNEL_GZIP
Lasse Collin3ebe1242011-01-12 17:01:23 -0800112 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800113 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100114 The linux kernel is a kind of self-extracting executable.
115 Several compression algorithms are available, which differ
116 in efficiency, compression and decompression speed.
117 Compression speed is only relevant when building a kernel.
118 Decompression speed is relevant at each boot.
119
120 If you have any problems with bzip2 or lzma compressed
121 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
122 version of this functionality (bzip2 only), for 2.4, was
123 supplied by Christian Ludwig)
124
125 High compression options are mostly useful for users, who
126 are low on disk space (embedded systems), but for whom ram
127 size matters less.
128
129 If in doubt, select 'gzip'
130
131config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800132 bool "Gzip"
133 depends on HAVE_KERNEL_GZIP
134 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800135 The old and tried gzip compression. It provides a good balance
136 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100137
138config KERNEL_BZIP2
139 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800140 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100141 help
142 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700143 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800144 size is about 10% smaller with bzip2, in comparison to gzip.
145 Bzip2 uses a large amount of memory. For modern kernels you
146 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100147
148config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800149 bool "LZMA"
150 depends on HAVE_KERNEL_LZMA
151 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700152 This compression algorithm's ratio is best. Decompression speed
153 is between gzip and bzip2. Compression is slowest.
154 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100155
Lasse Collin3ebe1242011-01-12 17:01:23 -0800156config KERNEL_XZ
157 bool "XZ"
158 depends on HAVE_KERNEL_XZ
159 help
160 XZ uses the LZMA2 algorithm and instruction set specific
161 BCJ filters which can improve compression ratio of executable
162 code. The size of the kernel is about 30% smaller with XZ in
163 comparison to gzip. On architectures for which there is a BCJ
164 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
165 will create a few percent smaller kernel than plain LZMA.
166
167 The speed is about the same as with LZMA: The decompression
168 speed of XZ is better than that of bzip2 but worse than gzip
169 and LZO. Compression is slow.
170
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800171config KERNEL_LZO
172 bool "LZO"
173 depends on HAVE_KERNEL_LZO
174 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700175 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200176 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800177 (both compression and decompression) is the fastest.
178
Alain Knaff30d65db2009-01-04 22:46:17 +0100179endchoice
180
Josh Triplettbd5dc172011-06-15 15:08:28 -0700181config DEFAULT_HOSTNAME
182 string "Default hostname"
183 default "(none)"
184 help
185 This option determines the default system hostname before userspace
186 calls sethostname(2). The kernel traditionally uses "(none)" here,
187 but you may wish to use a different default here to make a minimal
188 system more usable with less configuration.
189
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190config SWAP
191 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200192 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 default y
194 help
195 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100196 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 used to provide more virtual memory than the actual RAM present
198 in your computer. If unsure say Y.
199
200config SYSVIPC
201 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 ---help---
203 Inter Process Communication is a suite of library functions and
204 system calls which let processes (running programs) synchronize and
205 exchange information. It is generally considered to be a good thing,
206 and some programs won't run unless you say Y here. In particular, if
207 you want to run the DOS emulator dosemu under Linux (read the
208 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
209 you'll need to say Y here.
210
211 You can find documentation about IPC with "info ipc" and also in
212 section 6.4 of the Linux Programmer's Guide, available from
213 <http://www.tldp.org/guides.html>.
214
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800215config SYSVIPC_SYSCTL
216 bool
217 depends on SYSVIPC
218 depends on SYSCTL
219 default y
220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221config POSIX_MQUEUE
222 bool "POSIX Message Queues"
223 depends on NET && EXPERIMENTAL
224 ---help---
225 POSIX variant of message queues is a part of IPC. In POSIX message
226 queues every message has a priority which decides about succession
227 of receiving it by a process. If you want to compile and run
228 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200229 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 POSIX message queues are visible as a filesystem called 'mqueue'
232 and can be mounted somewhere if you want to do filesystem
233 operations on message queues.
234
235 If unsure, say Y.
236
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700237config POSIX_MQUEUE_SYSCTL
238 bool
239 depends on POSIX_MQUEUE
240 depends on SYSCTL
241 default y
242
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530243config FHANDLE
244 bool "open by fhandle syscalls"
245 select EXPORTFS
246 help
247 If you say Y here, a user level program will be able to map
248 file names to handle and then later use the handle for
249 different file system operations. This is useful in implementing
250 userspace file servers, which now track files using handles instead
251 of names. The handle would remain the same even if file names
252 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
253 syscalls.
254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255config AUDIT
256 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100257 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 help
259 Enable auditing infrastructure that can be used with another
260 kernel subsystem, such as SELinux (which requires this for
261 logging of avc messages output). Does not do system-call
262 auditing without CONFIG_AUDITSYSCALL.
263
264config AUDITSYSCALL
265 bool "Enable system-call auditing support"
Will Deacon8f827a12012-07-06 15:48:16 +0100266 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 default y if SECURITY_SELINUX
268 help
269 Enable low-overhead system-call auditing infrastructure that
270 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500271 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
Eric Paris939a67f2009-12-17 20:12:06 -0500273config AUDIT_WATCH
274 def_bool y
275 depends on AUDITSYSCALL
276 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
Al Viro74c3cbe2007-07-22 08:04:18 -0400278config AUDIT_TREE
279 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400280 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500281 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400282
Eric Paris633b4542012-01-03 14:23:08 -0500283config AUDIT_LOGINUID_IMMUTABLE
284 bool "Make audit loginuid immutable"
285 depends on AUDIT
286 help
Linus Torvaldsf429ee32012-01-17 16:06:51 -0800287 The config option toggles if a task setting its loginuid requires
Eric Paris633b4542012-01-03 14:23:08 -0500288 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
289 but should instead only allow setting its loginuid if it was never
290 previously set. On systems which use systemd or a similar central
291 process to restart login services this should be set to true. On older
292 systems in which an admin would typically have to directly stop and
293 start processes this should be set to false. Setting this to true allows
294 one to drop potentially dangerous capabilites from the login tasks,
295 but may not be backwards compatible with older init systems.
296
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000297source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200298source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000299
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200300menu "CPU/Task time and stats accounting"
301
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200302choice
303 prompt "Cputime accounting"
304 default TICK_CPU_ACCOUNTING if !PPC64
305 default VIRT_CPU_ACCOUNTING if PPC64
306
307# Kind of a stub config for the pure tick based cputime accounting
308config TICK_CPU_ACCOUNTING
309 bool "Simple tick based cputime accounting"
310 depends on !S390
311 help
312 This is the basic tick based cputime accounting that maintains
313 statistics about user, system and idle time spent on per jiffies
314 granularity.
315
316 If unsure, say Y.
317
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200318config VIRT_CPU_ACCOUNTING
319 bool "Deterministic task and CPU time accounting"
320 depends on HAVE_VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200321 help
322 Select this option to enable more accurate task and CPU time
323 accounting. This is done by reading a CPU counter on each
324 kernel entry and exit and on transitions within the kernel
325 between system, softirq and hardirq state, so there is a
326 small performance impact. In the case of s390 or IBM POWER > 5,
327 this also enables accounting of stolen time on logically-partitioned
328 systems.
329
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200330config IRQ_TIME_ACCOUNTING
331 bool "Fine granularity task level IRQ time accounting"
332 depends on HAVE_IRQ_TIME_ACCOUNTING
333 help
334 Select this option to enable fine granularity task irq time
335 accounting. This is done by reading a timestamp on each
336 transitions between softirq and hardirq state, so there can be a
337 small performance impact.
338
339 If in doubt, say N here.
340
341endchoice
342
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200343config BSD_PROCESS_ACCT
344 bool "BSD Process Accounting"
345 help
346 If you say Y here, a user level program will be able to instruct the
347 kernel (via a special system call) to write process accounting
348 information to a file: whenever a process exits, information about
349 that process will be appended to the file by the kernel. The
350 information includes things such as creation time, owning user,
351 command name, memory usage, controlling terminal etc. (the complete
352 list is in the struct acct in <file:include/linux/acct.h>). It is
353 up to the user level program to do useful things with this
354 information. This is generally a good idea, so say Y.
355
356config BSD_PROCESS_ACCT_V3
357 bool "BSD Process Accounting version 3 file format"
358 depends on BSD_PROCESS_ACCT
359 default n
360 help
361 If you say Y here, the process accounting information is written
362 in a new file format that also logs the process IDs of each
363 process and it's parent. Note that this file format is incompatible
364 with previous v0/v1/v2 file formats, so you will need updated tools
365 for processing it. A preliminary version of these tools is available
366 at <http://www.gnu.org/software/acct/>.
367
368config TASKSTATS
369 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
370 depends on NET
371 default n
372 help
373 Export selected statistics for tasks/processes through the
374 generic netlink interface. Unlike BSD process accounting, the
375 statistics are available during the lifetime of tasks/processes as
376 responses to commands. Like BSD accounting, they are sent to user
377 space on task exit.
378
379 Say N if unsure.
380
381config TASK_DELAY_ACCT
382 bool "Enable per-task delay accounting (EXPERIMENTAL)"
383 depends on TASKSTATS
384 help
385 Collect information on time spent by a task waiting for system
386 resources like cpu, synchronous block I/O completion and swapping
387 in pages. Such statistics can help in setting a task's priorities
388 relative to other tasks for cpu, io, rss limits etc.
389
390 Say N if unsure.
391
392config TASK_XACCT
393 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
394 depends on TASKSTATS
395 help
396 Collect extended task accounting data and send the data
397 to userland for processing over the taskstats interface.
398
399 Say N if unsure.
400
401config TASK_IO_ACCOUNTING
402 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
403 depends on TASK_XACCT
404 help
405 Collect information on the number of bytes of storage I/O which this
406 task has caused.
407
408 Say N if unsure.
409
410endmenu # "CPU/Task time and stats accounting"
411
Mike Travisc903ff82009-01-15 12:28:29 -0800412menu "RCU Subsystem"
413
414choice
415 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700416 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800417
Mike Travisc903ff82009-01-15 12:28:29 -0800418config TREE_RCU
419 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700420 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800421 help
422 This option selects the RCU implementation that is
423 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700424 thousands of CPUs. It also scales down nicely to
425 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800426
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700427config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700428 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700429 depends on PREEMPT && SMP
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700430 help
431 This option selects the RCU implementation that is
432 designed for very large SMP systems with hundreds or
433 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700434 is also required. It also scales down nicely to
435 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700436
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700437config TINY_RCU
438 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700439 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700440 help
441 This option selects the RCU implementation that is
442 designed for UP systems from which real-time response
443 is not required. This option greatly reduces the
444 memory footprint of RCU.
445
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700446config TINY_PREEMPT_RCU
447 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700448 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700449 help
450 This option selects the RCU implementation that is designed
451 for real-time UP systems. This option greatly reduces the
452 memory footprint of RCU.
453
Mike Travisc903ff82009-01-15 12:28:29 -0800454endchoice
455
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700456config PREEMPT_RCU
457 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
458 help
459 This option enables preemptible-RCU code that is common between
460 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
461
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100462config CONTEXT_TRACKING
463 bool
464
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200465config RCU_USER_QS
466 bool "Consider userspace as in RCU extended quiescent state"
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100467 depends on HAVE_CONTEXT_TRACKING && SMP
468 select CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200469 help
470 This option sets hooks on kernel / userspace boundaries and
471 puts RCU in extended quiescent state when the CPU runs in
472 userspace. It means that when a CPU runs in userspace, it is
473 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700474 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200475
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200476 Unless you want to hack and help the development of the full
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100477 dynticks mode, you shouldn't enable this option. It also
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700478 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200479
480 If unsure say N
481
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100482config CONTEXT_TRACKING_FORCE
483 bool "Force context tracking"
484 depends on CONTEXT_TRACKING
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200485 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100486 Probe on user/kernel boundaries by default in order to
487 test the features that rely on it such as userspace RCU extended
488 quiescent states.
489 This test is there for debugging until we have a real user like the
490 full dynticks mode.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200491
Mike Travisc903ff82009-01-15 12:28:29 -0800492config RCU_FANOUT
493 int "Tree-based hierarchical RCU fanout value"
494 range 2 64 if 64BIT
495 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700496 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800497 default 64 if 64BIT
498 default 32 if !64BIT
499 help
500 This option controls the fanout of hierarchical implementations
501 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700502 large numbers of CPUs. This value must be at least the fourth
503 root of NR_CPUS, which allows NR_CPUS to be insanely large.
504 The default value of RCU_FANOUT should be used for production
505 systems, but if you are stress-testing the RCU implementation
506 itself, small RCU_FANOUT values allow you to test large-system
507 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800508
509 Select a specific number if testing RCU itself.
510 Take the default if unsure.
511
Paul E. McKenney8932a632012-04-19 12:20:14 -0700512config RCU_FANOUT_LEAF
513 int "Tree-based hierarchical RCU leaf-level fanout value"
514 range 2 RCU_FANOUT if 64BIT
515 range 2 RCU_FANOUT if !64BIT
516 depends on TREE_RCU || TREE_PREEMPT_RCU
517 default 16
518 help
519 This option controls the leaf-level fanout of hierarchical
520 implementations of RCU, and allows trading off cache misses
521 against lock contention. Systems that synchronize their
522 scheduling-clock interrupts for energy-efficiency reasons will
523 want the default because the smaller leaf-level fanout keeps
524 lock contention levels acceptably low. Very large systems
525 (hundreds or thousands of CPUs) will instead want to set this
526 value to the maximum value possible in order to reduce the
527 number of cache misses incurred during RCU's grace-period
528 initialization. These systems tend to run CPU-bound, and thus
529 are not helped by synchronized interrupts, and thus tend to
530 skew them, which reduces lock contention enough that large
531 leaf-level fanouts work well.
532
533 Select a specific number if testing RCU itself.
534
535 Select the maximum permissible value for large systems.
536
537 Take the default if unsure.
538
Mike Travisc903ff82009-01-15 12:28:29 -0800539config RCU_FANOUT_EXACT
540 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700541 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800542 default n
543 help
544 This option forces use of the exact RCU_FANOUT value specified,
545 regardless of imbalances in the hierarchy. This is useful for
546 testing RCU itself, and might one day be useful on systems with
547 strong NUMA behavior.
548
549 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
550
551 Say N if unsure.
552
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800553config RCU_FAST_NO_HZ
554 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700555 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800556 default n
557 help
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700558 This option causes RCU to attempt to accelerate grace periods in
559 order to allow CPUs to enter dynticks-idle state more quickly.
560 On the other hand, this option increases the overhead of the
561 dynticks-idle checking, thus degrading scheduling latency.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800562
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700563 Say Y if energy efficiency is critically important, and you don't
564 care about real-time response.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800565
566 Say N if you are unsure.
567
Mike Travisc903ff82009-01-15 12:28:29 -0800568config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700569 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800570 select DEBUG_FS
571 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700572 This option provides tracing for the TREE_RCU and
573 TREE_PREEMPT_RCU implementations, permitting Makefile to
574 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800575
Paul E. McKenney24278d12010-09-27 17:25:23 -0700576config RCU_BOOST
577 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800578 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700579 default n
580 help
581 This option boosts the priority of preempted RCU readers that
582 block the current preemptible RCU grace period for too long.
583 This option also prevents heavy loads from blocking RCU
584 callback invocation for all flavors of RCU.
585
586 Say Y here if you are working with real-time apps or heavy loads
587 Say N here if you are unsure.
588
589config RCU_BOOST_PRIO
590 int "Real-time priority to boost RCU readers to"
591 range 1 99
592 depends on RCU_BOOST
593 default 1
594 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700595 This option specifies the real-time priority to which long-term
596 preempted RCU readers are to be boosted. If you are working
597 with a real-time application that has one or more CPU-bound
598 threads running at a real-time priority level, you should set
599 RCU_BOOST_PRIO to a priority higher then the highest-priority
600 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
601 of 1 is appropriate in the common case, which is real-time
602 applications that do not have any CPU-bound threads.
603
604 Some real-time applications might not have a single real-time
605 thread that saturates a given CPU, but instead might have
606 multiple real-time threads that, taken together, fully utilize
607 that CPU. In this case, you should set RCU_BOOST_PRIO to
608 a priority higher than the lowest-priority thread that is
609 conspiring to prevent the CPU from running any non-real-time
610 tasks. For example, if one thread at priority 10 and another
611 thread at priority 5 are between themselves fully consuming
612 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
613 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700614
615 Specify the real-time priority, or take the default if unsure.
616
617config RCU_BOOST_DELAY
618 int "Milliseconds to delay boosting after RCU grace-period start"
619 range 0 3000
620 depends on RCU_BOOST
621 default 500
622 help
623 This option specifies the time to wait after the beginning of
624 a given grace period before priority-boosting preempted RCU
625 readers blocking that grace period. Note that any RCU reader
626 blocking an expedited RCU grace period is boosted immediately.
627
628 Accept the default if unsure.
629
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700630config RCU_NOCB_CPU
631 bool "Offload RCU callback processing from boot-selected CPUs"
632 depends on TREE_RCU || TREE_PREEMPT_RCU
633 default n
634 help
635 Use this option to reduce OS jitter for aggressive HPC or
636 real-time workloads. It can also be used to offload RCU
637 callback invocation to energy-efficient CPUs in battery-powered
638 asymmetric multiprocessors.
639
640 This option offloads callback invocation from the set of
641 CPUs specified at boot time by the rcu_nocbs parameter.
642 For each such CPU, a kthread ("rcuoN") will be created to
643 invoke callbacks, where the "N" is the CPU being offloaded.
644 Nothing prevents this kthread from running on the specified
645 CPUs, but (1) the kthreads may be preempted between each
646 callback, and (2) affinity or cgroups can be used to force
647 the kthreads to run on whatever set of CPUs is desired.
648
649 Say Y here if you want reduced OS jitter on selected CPUs.
650 Say N here if you are unsure.
651
Mike Travisc903ff82009-01-15 12:28:29 -0800652endmenu # "RCU Subsystem"
653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700655 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 ---help---
657 This option enables the complete Linux kernel ".config" file
658 contents to be saved in the kernel. It provides documentation
659 of which kernel options are used in a running kernel or in an
660 on-disk kernel. This information can be extracted from the kernel
661 image file with the script scripts/extract-ikconfig and used as
662 input to rebuild the current kernel or to build another kernel.
663 It can also be extracted from a running kernel by reading
664 /proc/config.gz if enabled (below).
665
666config IKCONFIG_PROC
667 bool "Enable access to .config through /proc/config.gz"
668 depends on IKCONFIG && PROC_FS
669 ---help---
670 This option enables access to the kernel configuration file
671 through /proc/config.gz.
672
Alistair John Strachan794543a2007-05-08 00:31:15 -0700673config LOG_BUF_SHIFT
674 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
675 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700676 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700677 help
678 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700679 Examples:
680 17 => 128 KB
681 16 => 64 KB
682 15 => 32 KB
683 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700684 13 => 8 KB
685 12 => 4 KB
686
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800687#
688# Architectures with an unreliable sched_clock() should select this:
689#
690config HAVE_UNSTABLE_SCHED_CLOCK
691 bool
692
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200693#
694# For architectures that want to enable the support for NUMA-affine scheduler
695# balancing logic:
696#
697config ARCH_SUPPORTS_NUMA_BALANCING
698 bool
699
700# For architectures that (ab)use NUMA to represent different memory regions
701# all cpu-local but of different latencies, such as SuperH.
702#
703config ARCH_WANT_NUMA_VARIABLE_LOCALITY
704 bool
705
706#
707# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
708config ARCH_WANTS_PROT_NUMA_PROT_NONE
709 bool
710
711config ARCH_USES_NUMA_PROT_NONE
712 bool
713 default y
714 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
715 depends on NUMA_BALANCING
716
Mel Gorman1a687c22012-11-22 11:16:36 +0000717config NUMA_BALANCING_DEFAULT_ENABLED
718 bool "Automatically enable NUMA aware memory/task placement"
719 default y
720 depends on NUMA_BALANCING
721 help
722 If set, autonumic NUMA balancing will be enabled if running on a NUMA
723 machine.
724
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200725config NUMA_BALANCING
726 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200727 depends on ARCH_SUPPORTS_NUMA_BALANCING
728 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
729 depends on SMP && NUMA && MIGRATION
730 help
731 This option adds support for automatic NUMA aware memory/task placement.
732 The mechanism is quite primitive and is based on migrating memory when
733 it is references to the node the task is running on.
734
735 This system will be inactive on UMA systems.
736
Li Zefan23964d22009-01-15 13:50:58 -0800737menuconfig CGROUPS
738 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800739 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700740 help
Li Zefan23964d22009-01-15 13:50:58 -0800741 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800742 use with process control subsystems such as Cpusets, CFS, memory
743 controls or device isolation.
744 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800745 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800746 - Documentation/cgroups/ (features for grouping, isolation
747 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700748
749 Say N if unsure.
750
Li Zefan23964d22009-01-15 13:50:58 -0800751if CGROUPS
752
Paul Menage006cb992007-10-18 23:39:43 -0700753config CGROUP_DEBUG
754 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700755 default n
Paul Menage006cb992007-10-18 23:39:43 -0700756 help
757 This option enables a simple cgroup subsystem that
758 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800759 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700760
Li Zefan23964d22009-01-15 13:50:58 -0800761 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700762
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700763config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800764 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800765 help
766 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700767 cgroup.
768
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700769config CGROUP_DEVICE
770 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700771 help
772 Provides a cgroup implementing whitelists for devices which
773 a process in the cgroup can mknod or open.
774
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775config CPUSETS
776 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700778 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 allow dynamically partitioning a system into sets of CPUs and
780 Memory Nodes and assigning tasks to run only within those sets.
781 This is primarily useful on large SMP or NUMA systems.
782
783 Say N if unsure.
784
Li Zefan23964d22009-01-15 13:50:58 -0800785config PROC_PID_CPUSET
786 bool "Include legacy /proc/<pid>/cpuset file"
787 depends on CPUSETS
788 default y
789
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100790config CGROUP_CPUACCT
791 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100792 help
793 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800794 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100795
Pavel Emelianove552b662008-02-07 00:13:49 -0800796config RESOURCE_COUNTERS
797 bool "Resource counters"
798 help
799 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800800 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800801
Andrew Mortonc255a452012-07-31 16:43:02 -0700802config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800803 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700804 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700805 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800806 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700807 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100808 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800809
810 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700811 associated with each page of memory in the system. By this,
812 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
813 usage tracking struct at boot. Total amount of this is printed out
814 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800815
816 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700817 sure you need the memory resource controller. Even when you enable
818 this, you can set "cgroup_disable=memory" at your boot option to
819 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800820 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800821
Balbir Singhcf475ad2008-04-29 01:00:16 -0700822 This config option also selects MM_OWNER config option, which
823 could in turn add some fork/exit overhead.
824
Andrew Mortonc255a452012-07-31 16:43:02 -0700825config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700826 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700827 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800828 help
829 Add swap management feature to memory resource controller. When you
830 enable this, you can limit mem+swap usage per cgroup. In other words,
831 when you disable this, memory resource controller has no cares to
832 usage of swap...a process can exhaust all of the swap. This extension
833 is useful when you want to avoid exhaustion swap but this itself
834 adds more overheads and consumes memory for remembering information.
835 Especially if you use 32bit system or small memory system, please
836 be careful about enabling this. When memory resource controller
837 is disabled by boot option, this will be automatically disabled and
838 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700839 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700840 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
841 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -0700842config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -0800843 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700844 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800845 default y
846 help
847 Memory Resource Controller Swap Extension comes with its price in
848 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700849 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800850 and let the user enable it by swapaccount boot command line
851 parameter should have this option unselected.
852 For those who want to have the feature enabled by default should
853 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700854 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700855config MEMCG_KMEM
Glauber Costae5671df2011-12-11 21:47:01 +0000856 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
Andrew Mortonc255a452012-07-31 16:43:02 -0700857 depends on MEMCG && EXPERIMENTAL
Glauber Costa510fc4e2012-12-18 14:21:47 -0800858 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +0000859 help
860 The Kernel Memory extension for Memory Resource Controller can limit
861 the amount of memory used by kernel objects in the system. Those are
862 fundamentally different from the entities handled by the standard
863 Memory Controller, which are page-based, and can be swapped. Users of
864 the kmem extension can use it to guarantee that no group of processes
865 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800866
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700867config CGROUP_HUGETLB
868 bool "HugeTLB Resource Controller for Control Groups"
869 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
870 default n
871 help
872 Provides a cgroup Resource Controller for HugeTLB pages.
873 When you enable this, you can put a per cgroup limit on HugeTLB usage.
874 The limit is enforced during page fault. Since HugeTLB doesn't
875 support page reclaim, enforcing the limit at page fault time implies
876 that, the application will get SIGBUS signal if it tries to access
877 HugeTLB pages beyond its limit. This requires the application to know
878 beforehand how much HugeTLB pages it would require for its use. The
879 control group is tracked in the third page lru pointer. This means
880 that we cannot use the controller with huge page less than 3 pages.
881
Stephane Eraniane5d13672011-02-14 11:20:01 +0200882config CGROUP_PERF
883 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
884 depends on PERF_EVENTS && CGROUPS
885 help
886 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800887 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200888 designated cpu.
889
890 Say N if unsure.
891
Dhaval Giani7c941432010-01-20 13:26:18 +0100892menuconfig CGROUP_SCHED
893 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100894 default n
895 help
896 This feature lets CPU scheduler recognize task groups and control CPU
897 bandwidth allocation to such task groups. It uses cgroups to group
898 tasks.
899
900if CGROUP_SCHED
901config FAIR_GROUP_SCHED
902 bool "Group scheduling for SCHED_OTHER"
903 depends on CGROUP_SCHED
904 default CGROUP_SCHED
905
Paul Turnerab84d312011-07-21 09:43:28 -0700906config CFS_BANDWIDTH
907 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
908 depends on EXPERIMENTAL
909 depends on FAIR_GROUP_SCHED
910 default n
911 help
912 This option allows users to define CPU bandwidth rates (limits) for
913 tasks running within the fair group scheduler. Groups with no limit
914 set are considered to be unconstrained and will run with no
915 restriction.
916 See tip/Documentation/scheduler/sched-bwc.txt for more information.
917
Dhaval Giani7c941432010-01-20 13:26:18 +0100918config RT_GROUP_SCHED
919 bool "Group scheduling for SCHED_RR/FIFO"
920 depends on EXPERIMENTAL
921 depends on CGROUP_SCHED
922 default n
923 help
924 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800925 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100926 schedule realtime tasks for non-root users until you allocate
927 realtime bandwidth for them.
928 See Documentation/scheduler/sched-rt-group.txt for more information.
929
930endif #CGROUP_SCHED
931
Vivek Goyalafc24d42010-04-26 19:27:56 +0200932config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -0800933 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700934 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200935 default n
936 ---help---
937 Generic block IO controller cgroup interface. This is the common
938 cgroup interface which should be used by various IO controlling
939 policies.
940
941 Currently, CFQ IO scheduler uses it to recognize task groups and
942 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400943 to such task groups. It is also used by bio throttling logic in
944 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200945
946 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400947 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000948 enabling proportional weight division of disk bandwidth in CFQ, set
949 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000950 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200951
952 See Documentation/cgroups/blkio-controller.txt for more information.
953
954config DEBUG_BLK_CGROUP
955 bool "Enable Block IO controller debugging"
956 depends on BLK_CGROUP
957 default n
958 ---help---
959 Enable some debugging help. Currently it exports additional stat
960 files in a cgroup which can be useful for debugging.
961
Li Zefan23964d22009-01-15 13:50:58 -0800962endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800963
Cyrill Gorcunov067bce12012-01-12 17:20:49 -0800964config CHECKPOINT_RESTORE
965 bool "Checkpoint/restore support" if EXPERT
966 default n
967 help
968 Enables additional kernel features in a sake of checkpoint/restore.
969 In particular it adds auxiliary prctl codes to setup process text,
970 data and heap segment sizes, and a few additional /proc filesystem
971 entries.
972
973 If unsure, say N here.
974
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700975menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800976 bool "Namespaces support" if EXPERT
977 default !EXPERT
Pavel Emelyanovc5289a692008-02-08 04:18:19 -0800978 help
979 Provides the way to make tasks work with different objects using
980 the same id. For example same IPC id may refer to different objects
981 or same user id or pid may refer to different tasks when used in
982 different namespaces.
983
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700984if NAMESPACES
985
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800986config UTS_NS
987 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700988 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800989 help
990 In this namespace tasks see different info provided with the
991 uname() system call
992
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800993config IPC_NS
994 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700995 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700996 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800997 help
998 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700999 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001000
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001001config USER_NS
1002 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001003 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001004 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001005 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001006
Eric W. Biederman5673a942011-11-17 10:23:55 -08001007 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001008 help
1009 This allows containers, i.e. vservers, to use user namespaces
1010 to provide different user info for different servers.
1011 If unsure, say N.
1012
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001013config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001014 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001015 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001016 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001017 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001018 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001019 pid namespaces. This is a building block of containers.
1020
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001021config NET_NS
1022 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001023 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001024 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001025 help
1026 Allow user space to create what appear to be multiple instances
1027 of the network stack.
1028
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001029endif # NAMESPACES
1030
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001031config UIDGID_CONVERTED
1032 # True if all of the selected software conmponents are known
1033 # to have uid_t and gid_t converted to kuid_t and kgid_t
1034 # where appropriate and are otherwise safe to use with
1035 # the user namespace.
1036 bool
1037 default y
1038
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001039 # Networking
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001040 depends on NET_9P = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001041
1042 # Filesystems
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001043 depends on 9P_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001044 depends on AFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001045 depends on CEPH_FS = n
1046 depends on CIFS = n
1047 depends on CODA_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001048 depends on GFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001049 depends on NCP_FS = n
1050 depends on NFSD = n
1051 depends on NFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001052 depends on OCFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001053 depends on XFS_FS = n
1054
Eric W. Biederman5673a942011-11-17 10:23:55 -08001055config UIDGID_STRICT_TYPE_CHECKS
1056 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001057 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001058 default n
1059 help
1060 While the nececessary conversions are being added to all subsystems this option allows
1061 the code to continue to build for unconverted subsystems.
1062
1063 Say Y here if you want the strict type checking enabled
1064
Mike Galbraith5091faa2010-11-30 14:18:03 +01001065config SCHED_AUTOGROUP
1066 bool "Automatic process group scheduling"
1067 select EVENTFD
1068 select CGROUPS
1069 select CGROUP_SCHED
1070 select FAIR_GROUP_SCHED
1071 help
1072 This option optimizes the scheduler for common desktop workloads by
1073 automatically creating and populating task groups. This separation
1074 of workloads isolates aggressive CPU burners (like build jobs) from
1075 desktop applications. Task group autogeneration is currently based
1076 upon task session.
1077
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001078config MM_OWNER
1079 bool
1080
1081config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001082 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001083 depends on SYSFS
1084 default n
1085 help
1086 This option adds code that switches the layout of the "block" class
1087 devices, to not show up in /sys/class/block/, but only in
1088 /sys/block/.
1089
1090 This switch is only active when the sysfs.deprecated=1 boot option is
1091 passed or the SYSFS_DEPRECATED_V2 option is set.
1092
1093 This option allows new kernels to run on old distributions and tools,
1094 which might get confused by /sys/class/block/. Since 2007/2008 all
1095 major distributions and tools handle this just fine.
1096
1097 Recent distributions and userspace tools after 2009/2010 depend on
1098 the existence of /sys/class/block/, and will not work with this
1099 option enabled.
1100
1101 Only if you are using a new kernel on an old distribution, you might
1102 need to say Y here.
1103
1104config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001105 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001106 default n
1107 depends on SYSFS
1108 depends on SYSFS_DEPRECATED
1109 help
1110 Enable deprecated sysfs by default.
1111
1112 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1113 option.
1114
1115 Only if you are using a new kernel on an old distribution, you might
1116 need to say Y here. Even then, odds are you would not need it
1117 enabled, you can always pass the boot option if absolutely necessary.
1118
1119config RELAY
1120 bool "Kernel->user space relay support (formerly relayfs)"
1121 help
1122 This option enables support for relay interface support in
1123 certain file systems (such as debugfs).
1124 It is designed to provide an efficient mechanism for tools and
1125 facilities to relay large amounts of data from kernel space to
1126 user space.
1127
1128 If unsure, say N.
1129
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001130config BLK_DEV_INITRD
1131 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1132 depends on BROKEN || !FRV
1133 help
1134 The initial RAM filesystem is a ramfs which is loaded by the
1135 boot loader (loadlin or lilo) and that is mounted as root
1136 before the normal boot procedure. It is typically used to
1137 load modules needed to mount the "real" root file system,
1138 etc. See <file:Documentation/initrd.txt> for details.
1139
1140 If RAM disk support (BLK_DEV_RAM) is also included, this
1141 also enables initial RAM disk (initrd) support and adds
1142 15 Kbytes (more on some other architectures) to the kernel size.
1143
1144 If unsure say Y.
1145
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001146if BLK_DEV_INITRD
1147
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001148source "usr/Kconfig"
1149
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001150endif
1151
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001152config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001153 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001154 help
1155 Enabling this option will pass "-Os" instead of "-O2" to gcc
1156 resulting in a smaller kernel.
1157
jkacur775a7222008-07-16 00:31:16 +02001158 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001159
Randy Dunlap08470622006-09-30 23:28:13 -07001160config SYSCTL
1161 bool
1162
Randy Dunlapb943c462009-03-10 12:55:46 -07001163config ANON_INODES
1164 bool
1165
David Rientjes6a108a12011-01-20 14:44:16 -08001166menuconfig EXPERT
1167 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001168 # Unhide debug options, to make the on-by-default options visible
1169 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 help
1171 This option allows certain base kernel options and settings
1172 to be disabled or tweaked. This is for specialized
1173 environments which can tolerate a "non-standard" kernel.
1174 Only use this if you really know what you are doing.
1175
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001176config HAVE_UID16
1177 bool
1178
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001179config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001180 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001181 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001182 default y
1183 help
1184 This enables the legacy 16-bit UID syscall wrappers.
1185
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001186config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001187 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001188 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001189 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001190 select SYSCTL
1191 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001192 sys_sysctl uses binary paths that have been found challenging
1193 to properly maintain and use. The interface in /proc/sys
1194 using paths with ascii names is now the primary path to this
1195 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001196
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001197 Almost nothing using the binary sysctl interface so if you are
1198 trying to save some space it is probably safe to disable this,
1199 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001200
WANG Congc736de62011-11-02 13:39:25 -07001201 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001202
Catalin Marinas7ac57a82012-10-08 16:28:16 -07001203config SYSCTL_EXCEPTION_TRACE
1204 bool
1205 help
1206 Enable support for /proc/sys/debug/exception-trace.
1207
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001209 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 default y
1211 help
1212 Say Y here to let the kernel print out symbolic crash information and
1213 symbolic stack backtraces. This increases the size of the kernel
1214 somewhat, as all symbols have to be loaded into the kernel image.
1215
1216config KALLSYMS_ALL
1217 bool "Include all symbols in kallsyms"
1218 depends on DEBUG_KERNEL && KALLSYMS
1219 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001220 Normally kallsyms only contains the symbols of functions for nicer
1221 OOPS messages and backtraces (i.e., symbols from the text and inittext
1222 sections). This is sufficient for most cases. And only in very rare
1223 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1224 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001226 This option makes sure that all symbols are loaded into the kernel
1227 image (i.e., symbols from all sections) in cost of increased kernel
1228 size (depending on the kernel configuration, it may be 300KiB or
1229 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001231 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001232
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001233config HOTPLUG
Greg Kroah-Hartman45f035a2012-09-04 17:01:08 -07001234 def_bool y
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001235
Matt Mackalld59745c2005-05-01 08:59:02 -07001236config PRINTK
1237 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001238 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001239 help
1240 This option enables normal printk support. Removing it
1241 eliminates most of the message strings from the kernel image
1242 and makes the kernel more or less silent. As this makes it
1243 very difficult to diagnose system problems, saying N here is
1244 strongly discouraged.
1245
Matt Mackallc8538a72005-05-01 08:59:01 -07001246config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001247 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001248 default y
1249 help
1250 Disabling this option eliminates support for BUG and WARN, reducing
1251 the size of your kernel image and potentially quietly ignoring
1252 numerous fatal conditions. You should only consider disabling this
1253 option for embedded systems with no facilities for reporting errors.
1254 Just say Y.
1255
Matt Mackall708e9a72006-01-08 01:05:25 -08001256config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001257 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001258 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001259 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001260 help
1261 Enable support for generating core dumps. Disabling saves about 4k.
1262
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001263
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001264config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001265 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001266 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001267 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001268 default y
1269 help
1270 This option allows to disable the internal PC-Speaker
1271 support, saving some memory.
1272
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001273config HAVE_PCSPKR_PLATFORM
1274 bool
1275
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276config BASE_FULL
1277 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001278 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 help
1280 Disabling this option reduces the size of miscellaneous core
1281 kernel data structures. This saves memory on small machines,
1282 but may reduce performance.
1283
1284config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001285 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001287 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 help
1289 Disabling this option will cause the kernel to be built without
1290 support for "fast userspace mutexes". The resulting kernel may not
1291 run glibc-based applications correctly.
1292
1293config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001294 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001296 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 help
1298 Disabling this option will cause the kernel to be built without
1299 support for epoll family of system calls.
1300
Davide Libenzifba2afa2007-05-10 22:23:13 -07001301config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001302 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001303 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001304 default y
1305 help
1306 Enable the signalfd() system call that allows to receive signals
1307 on a file descriptor.
1308
1309 If unsure, say Y.
1310
Davide Libenzib215e282007-05-10 22:23:16 -07001311config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001312 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001313 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001314 default y
1315 help
1316 Enable the timerfd() system call that allows to receive timer
1317 events on a file descriptor.
1318
1319 If unsure, say Y.
1320
Davide Libenzie1ad7462007-05-10 22:23:19 -07001321config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001322 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001323 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001324 default y
1325 help
1326 Enable the eventfd() system call that allows to receive both
1327 kernel notification (ie. KAIO) or userspace notifications.
1328
1329 If unsure, say Y.
1330
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001332 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 default y
1334 depends on MMU
1335 help
1336 The shmem is an internal filesystem used to manage shared memory.
1337 It is backed by swap and manages resource limits. It is also exported
1338 to userspace as tmpfs if TMPFS is enabled. Disabling this
1339 option replaces shmem and tmpfs with the much simpler ramfs code,
1340 which may be appropriate on small systems without swap.
1341
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001342config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001343 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001344 default y
1345 help
1346 This option enables POSIX asynchronous I/O which may by used
1347 by some high performance threaded applications. Disabling
1348 this option saves about 7k.
1349
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001350config EMBEDDED
1351 bool "Embedded system"
1352 select EXPERT
1353 help
1354 This option should be enabled if compiling the kernel for
1355 an embedded system so certain expert options are available
1356 for configuration.
1357
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001358config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001359 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001360 help
1361 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001362
Peter Zijlstra906010b2009-09-21 16:08:49 +02001363config PERF_USE_VMALLOC
1364 bool
1365 help
1366 See tools/perf/design.txt for details
1367
Ingo Molnar57c0c152009-09-21 12:20:38 +02001368menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001369
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001370config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001371 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001372 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001373 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001374 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001375 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001376 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001377 Enable kernel support for various performance events provided
1378 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001379
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001380 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001381 use of generic tracepoints.
1382
1383 Most modern CPUs support performance events via performance
1384 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001385 types of hw events: such as instructions executed, cachemisses
1386 suffered, or branches mis-predicted - without slowing down the
1387 kernel or applications. These registers can also trigger interrupts
1388 when a threshold number of events have passed - and can thus be
1389 used to profile the code that runs on that CPU.
1390
Ingo Molnar57c0c152009-09-21 12:20:38 +02001391 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001392 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001393 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001394 provides per task and per CPU counters, and it provides event
1395 capabilities on top of those.
1396
1397 Say Y if unsure.
1398
Peter Zijlstra906010b2009-09-21 16:08:49 +02001399config DEBUG_PERF_USE_VMALLOC
1400 default n
1401 bool "Debug: use vmalloc to back perf mmap() buffers"
1402 depends on PERF_EVENTS && DEBUG_KERNEL
1403 select PERF_USE_VMALLOC
1404 help
1405 Use vmalloc memory to back perf mmap() buffers.
1406
1407 Mostly useful for debugging the vmalloc code on platforms
1408 that don't require it.
1409
1410 Say N if unsure.
1411
Thomas Gleixner0793a612008-12-04 20:12:29 +01001412endmenu
1413
Christoph Lameterf8891e52006-06-30 01:55:45 -07001414config VM_EVENT_COUNTERS
1415 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001416 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001417 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001418 VM event counters are needed for event counts to be shown.
1419 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001420 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001421 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001422
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001423config PCI_QUIRKS
1424 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001425 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001426 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001427 help
1428 This enables workarounds for various PCI chipset
1429 bugs/quirks. Disable this only if your target machine is
1430 unaffected by PCI quirks.
1431
Christoph Lameter41ecc552007-05-09 02:32:44 -07001432config SLUB_DEBUG
1433 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001434 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001435 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001436 help
1437 SLUB has extensive debug support features. Disabling these can
1438 result in significant savings in code size. This also disables
1439 SLUB sysfs support. /sys/slab will not exist and there will be
1440 no support for cache validation etc.
1441
Randy Dunlapb943c462009-03-10 12:55:46 -07001442config COMPAT_BRK
1443 bool "Disable heap randomization"
1444 default y
1445 help
1446 Randomizing heap placement makes heap exploits harder, but it
1447 also breaks ancient binaries (including anything libc5 based).
1448 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001449 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001450 /proc/sys/kernel/randomize_va_space to 2.
1451
1452 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1453
Christoph Lameter81819f02007-05-06 14:49:36 -07001454choice
1455 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001456 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001457 help
1458 This option allows to select a slab allocator.
1459
1460config SLAB
1461 bool "SLAB"
1462 help
1463 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001464 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001465 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001466
1467config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001468 bool "SLUB (Unqueued Allocator)"
1469 help
1470 SLUB is a slab allocator that minimizes cache line usage
1471 instead of managing queues of cached objects (SLAB approach).
1472 Per cpu caching is realized using slabs of objects instead
1473 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001474 and has enhanced diagnostics. SLUB is the default choice for
1475 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001476
1477config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001478 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001479 bool "SLOB (Simple Allocator)"
1480 help
Matt Mackall37291452008-02-04 22:29:38 -08001481 SLOB replaces the stock allocator with a drastically simpler
1482 allocator. SLOB is generally more space efficient but
1483 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001484
1485endchoice
1486
Jie Zhangea637632009-12-14 18:00:02 -08001487config MMAP_ALLOW_UNINITIALIZED
1488 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001489 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001490 default n
1491 help
1492 Normally, and according to the Linux spec, anonymous memory obtained
1493 from mmap() has it's contents cleared before it is passed to
1494 userspace. Enabling this config option allows you to request that
1495 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1496 providing a huge performance boost. If this option is not enabled,
1497 then the flag will be ignored.
1498
1499 This is taken advantage of by uClibc's malloc(), and also by
1500 ELF-FDPIC binfmt's brk and stack allocator.
1501
1502 Because of the obvious security issues, this option should only be
1503 enabled on embedded devices where you control what is run in
1504 userspace. Since that isn't generally a problem on no-MMU systems,
1505 it is normally safe to say Y here.
1506
1507 See Documentation/nommu-mmap.txt for more information.
1508
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001509config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001510 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001511 help
1512 Say Y here to enable the extended profiling support mechanisms used
1513 by profilers such as OProfile.
1514
Ingo Molnar5f87f112008-07-23 14:15:22 +02001515#
1516# Place an empty function call at each tracepoint site. Can be
1517# dynamically changed for a probe function.
1518#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001519config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001520 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001521
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001522source "arch/Kconfig"
1523
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524endmenu # General setup
1525
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001526config HAVE_GENERIC_DMA_COHERENT
1527 bool
1528 default n
1529
Linus Torvalds158a9622008-01-02 13:04:48 -08001530config SLABINFO
1531 bool
1532 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001533 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001534 default y
1535
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001536config RT_MUTEXES
1537 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001538
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539config BASE_SMALL
1540 int
1541 default 0 if BASE_FULL
1542 default 1 if !BASE_FULL
1543
Jan Engelhardt66da5732007-07-15 23:39:29 -07001544menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 bool "Enable loadable module support"
1546 help
1547 Kernel modules are small pieces of compiled code which can
1548 be inserted in the running kernel, rather than being
1549 permanently built into the kernel. You use the "modprobe"
1550 tool to add (and sometimes remove) them. If you say Y here,
1551 many parts of the kernel can be built as modules (by
1552 answering M instead of Y where indicated): this is most
1553 useful for infrequently used options which are not required
1554 for booting. For more information, see the man pages for
1555 modprobe, lsmod, modinfo, insmod and rmmod.
1556
1557 If you say Y here, you will need to run "make
1558 modules_install" to put the modules under /lib/modules/
1559 where modprobe can find them (you may need to be root to do
1560 this).
1561
1562 If unsure, say Y.
1563
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001564if MODULES
1565
Linus Torvalds826e4502008-05-04 17:04:16 -07001566config MODULE_FORCE_LOAD
1567 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001568 default n
1569 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001570 Allow loading of modules without version information (ie. modprobe
1571 --force). Forced module loading sets the 'F' (forced) taint flag and
1572 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001573
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574config MODULE_UNLOAD
1575 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 help
1577 Without this option you will not be able to unload any
1578 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001579 anyway), which makes your kernel smaller, faster
1580 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581
1582config MODULE_FORCE_UNLOAD
1583 bool "Forced module unloading"
1584 depends on MODULE_UNLOAD && EXPERIMENTAL
1585 help
1586 This option allows you to force a module to unload, even if the
1587 kernel believes it is unsafe: the kernel will remove the module
1588 without waiting for anyone to stop using it (using the -f option to
1589 rmmod). This is mainly for kernel developers and desperate users.
1590 If unsure, say N.
1591
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001593 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 help
1595 Usually, you have to use modules compiled with your kernel.
1596 Saying Y here makes it sometimes possible to use modules
1597 compiled for different kernels, by adding enough information
1598 to the modules to (hopefully) spot any changes which would
1599 make them incompatible with the kernel you are running. If
1600 unsure, say N.
1601
1602config MODULE_SRCVERSION_ALL
1603 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604 help
1605 Modules which contain a MODULE_VERSION get an extra "srcversion"
1606 field inserted into their modinfo section, which contains a
1607 sum of the source files which made it. This helps maintainers
1608 see exactly which source was used to build a module (since
1609 others sometimes change the module source without updating
1610 the version). With this option, such a "srcversion" field
1611 will be created for all modules. If unsure, say N.
1612
Rusty Russell106a4ee2012-09-26 10:09:40 +01001613config MODULE_SIG
1614 bool "Module signature verification"
1615 depends on MODULES
David Howells48ba2462012-09-26 10:11:03 +01001616 select KEYS
1617 select CRYPTO
1618 select ASYMMETRIC_KEY_TYPE
1619 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1620 select PUBLIC_KEY_ALGO_RSA
1621 select ASN1
1622 select OID_REGISTRY
1623 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001624 help
1625 Check modules for valid signatures upon load: the signature
1626 is simply appended to the module. For more information see
1627 Documentation/module-signing.txt.
1628
David Howellsea0b6dc2012-09-26 10:09:50 +01001629 !!!WARNING!!! If you enable this option, you MUST make sure that the
1630 module DOES NOT get stripped after being signed. This includes the
1631 debuginfo strip done by some packagers (such as rpmbuild) and
1632 inclusion into an initramfs that wants the module size reduced.
1633
Rusty Russell106a4ee2012-09-26 10:09:40 +01001634config MODULE_SIG_FORCE
1635 bool "Require modules to be validly signed"
1636 depends on MODULE_SIG
1637 help
1638 Reject unsigned modules or signed modules for which we don't have a
1639 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001640
1641choice
1642 prompt "Which hash algorithm should modules be signed with?"
1643 depends on MODULE_SIG
1644 help
1645 This determines which sort of hashing algorithm will be used during
1646 signature generation. This algorithm _must_ be built into the kernel
1647 directly so that signature verification can take place. It is not
1648 possible to load a signed module containing the algorithm to check
1649 the signature on that module.
1650
1651config MODULE_SIG_SHA1
1652 bool "Sign modules with SHA-1"
1653 select CRYPTO_SHA1
1654
1655config MODULE_SIG_SHA224
1656 bool "Sign modules with SHA-224"
1657 select CRYPTO_SHA256
1658
1659config MODULE_SIG_SHA256
1660 bool "Sign modules with SHA-256"
1661 select CRYPTO_SHA256
1662
1663config MODULE_SIG_SHA384
1664 bool "Sign modules with SHA-384"
1665 select CRYPTO_SHA512
1666
1667config MODULE_SIG_SHA512
1668 bool "Sign modules with SHA-512"
1669 select CRYPTO_SHA512
1670
1671endchoice
1672
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001673endif # MODULES
1674
Rusty Russell98a79d62008-12-13 21:19:41 +10301675config INIT_ALL_POSSIBLE
1676 bool
1677 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301678 Back when each arch used to define their own cpu_online_mask and
1679 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301680 with all 1s, and others with all 0s. When they were centralised,
1681 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001682 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301683
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684config STOP_MACHINE
1685 bool
1686 default y
1687 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1688 help
1689 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001690
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001691source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001692
1693config PREEMPT_NOTIFIERS
1694 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001695
Steffen Klassert16295be2010-01-06 19:47:10 +11001696config PADATA
1697 depends on SMP
1698 bool
1699
Andi Kleen754b7b62012-10-04 17:11:27 -07001700# Can be selected by architectures with broken toolchains
1701# that get confused by correct const<->read_only section
1702# mappings
1703config BROKEN_RODATA
1704 bool
1705
David Howells4520c6a2012-09-21 23:31:13 +01001706config ASN1
1707 tristate
1708 help
1709 Build a simple ASN.1 grammar compiler that produces a bytecode output
1710 that can be interpreted by the ASN.1 stream decoder and used to
1711 inform it as to what tags are to be expected in a stream and what
1712 functions to call on what tags.
1713
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001714source "kernel/Kconfig.locks"