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Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config 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
36 bool "Prompt for development and/or incomplete code/drivers"
37 ---help---
38 Some of the various things that Linux supports (such as network
39 drivers, file systems, network protocols, etc.) can be in a state
40 of development where the functionality, stability, or the level of
41 testing is not yet high enough for general use. This is usually
42 known as the "alpha-test" phase among developers. If a feature is
43 currently in alpha-test, then the developers usually discourage
44 uninformed widespread use of this feature by the general public to
45 avoid "Why doesn't this work?" type mail messages. However, active
46 testing and use of these systems is welcomed. Just be aware that it
47 may not meet the normal level of reliability or it may fail to work
48 in some special cases. Detailed bug reports from people familiar
49 with the kernel internals are usually welcomed by the developers
50 (before submitting bug reports, please read the documents
51 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
52 <file:Documentation/BUG-HUNTING>, and
53 <file:Documentation/oops-tracing.txt> in the kernel source).
54
55 This option will also make obsoleted drivers available. These are
56 drivers that have been replaced by something else, and/or are
57 scheduled to be removed in a future kernel release.
58
59 Unless you intend to help test and develop a feature or driver that
60 falls into this category, or you have a situation that requires
61 using these features, you should probably say N here, which will
62 cause the configurator to present you with fewer choices. If
63 you say Y here, you will be offered the choice of using features or
64 drivers that are currently considered to be in the alpha-test phase.
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066config BROKEN
67 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69config BROKEN_ON_SMP
70 bool
71 depends on BROKEN || !SMP
72 default y
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074config INIT_ENV_ARG_LIMIT
75 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070076 default 32 if !UML
77 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 help
Randy Dunlap34ad92c22005-10-30 15:01:46 -080079 Maximum of each of the number of arguments and environment
80 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Roland McGrath84336462009-12-21 16:24:06 -080083config CROSS_COMPILE
84 string "Cross-compiler tool prefix"
85 help
86 Same as running 'make CROSS_COMPILE=prefix-' but stored for
87 default make runs in this kernel build directory. You don't
88 need to set this unless you want the configured kernel build
89 directory to select the cross-compiler automatically.
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091config LOCALVERSION
92 string "Local version - append to kernel release"
93 help
94 Append an extra string to the end of your kernel version.
95 This will show up when you type uname, for example.
96 The string you set here will be appended after the contents of
97 any files with a filename matching localversion* in your
98 object and source tree, in that order. Your total string can
99 be a maximum of 64 characters.
100
Ryan Andersonaaebf432005-07-31 04:57:49 -0400101config LOCALVERSION_AUTO
102 bool "Automatically append version information to the version string"
103 default y
104 help
105 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 release tree by looking for git tags that belong to the current
107 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400108
109 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400111 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200112 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400113
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200114 (The actual string used here is the first eight characters produced
115 by running the command:
116
117 $ git rev-parse --verify HEAD
118
119 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400120
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800121config HAVE_KERNEL_GZIP
122 bool
123
124config HAVE_KERNEL_BZIP2
125 bool
126
127config HAVE_KERNEL_LZMA
128 bool
129
Lasse Collin3ebe1242011-01-12 17:01:23 -0800130config HAVE_KERNEL_XZ
131 bool
132
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800133config HAVE_KERNEL_LZO
134 bool
135
Alain Knaff30d65db2009-01-04 22:46:17 +0100136choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800137 prompt "Kernel compression mode"
138 default KERNEL_GZIP
Lasse Collin3ebe1242011-01-12 17:01:23 -0800139 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 -0800140 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100141 The linux kernel is a kind of self-extracting executable.
142 Several compression algorithms are available, which differ
143 in efficiency, compression and decompression speed.
144 Compression speed is only relevant when building a kernel.
145 Decompression speed is relevant at each boot.
146
147 If you have any problems with bzip2 or lzma compressed
148 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
149 version of this functionality (bzip2 only), for 2.4, was
150 supplied by Christian Ludwig)
151
152 High compression options are mostly useful for users, who
153 are low on disk space (embedded systems), but for whom ram
154 size matters less.
155
156 If in doubt, select 'gzip'
157
158config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800159 bool "Gzip"
160 depends on HAVE_KERNEL_GZIP
161 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800162 The old and tried gzip compression. It provides a good balance
163 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
165config KERNEL_BZIP2
166 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800167 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100168 help
169 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700170 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800171 size is about 10% smaller with bzip2, in comparison to gzip.
172 Bzip2 uses a large amount of memory. For modern kernels you
173 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100174
175config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800176 bool "LZMA"
177 depends on HAVE_KERNEL_LZMA
178 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700179 This compression algorithm's ratio is best. Decompression speed
180 is between gzip and bzip2. Compression is slowest.
181 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100182
Lasse Collin3ebe1242011-01-12 17:01:23 -0800183config KERNEL_XZ
184 bool "XZ"
185 depends on HAVE_KERNEL_XZ
186 help
187 XZ uses the LZMA2 algorithm and instruction set specific
188 BCJ filters which can improve compression ratio of executable
189 code. The size of the kernel is about 30% smaller with XZ in
190 comparison to gzip. On architectures for which there is a BCJ
191 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
192 will create a few percent smaller kernel than plain LZMA.
193
194 The speed is about the same as with LZMA: The decompression
195 speed of XZ is better than that of bzip2 but worse than gzip
196 and LZO. Compression is slow.
197
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800198config KERNEL_LZO
199 bool "LZO"
200 depends on HAVE_KERNEL_LZO
201 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700202 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200203 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800204 (both compression and decompression) is the fastest.
205
Alain Knaff30d65db2009-01-04 22:46:17 +0100206endchoice
207
Josh Triplettbd5dc172011-06-15 15:08:28 -0700208config DEFAULT_HOSTNAME
209 string "Default hostname"
210 default "(none)"
211 help
212 This option determines the default system hostname before userspace
213 calls sethostname(2). The kernel traditionally uses "(none)" here,
214 but you may wish to use a different default here to make a minimal
215 system more usable with less configuration.
216
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217config SWAP
218 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200219 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 default y
221 help
222 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100223 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 used to provide more virtual memory than the actual RAM present
225 in your computer. If unsure say Y.
226
227config SYSVIPC
228 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 ---help---
230 Inter Process Communication is a suite of library functions and
231 system calls which let processes (running programs) synchronize and
232 exchange information. It is generally considered to be a good thing,
233 and some programs won't run unless you say Y here. In particular, if
234 you want to run the DOS emulator dosemu under Linux (read the
235 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
236 you'll need to say Y here.
237
238 You can find documentation about IPC with "info ipc" and also in
239 section 6.4 of the Linux Programmer's Guide, available from
240 <http://www.tldp.org/guides.html>.
241
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800242config SYSVIPC_SYSCTL
243 bool
244 depends on SYSVIPC
245 depends on SYSCTL
246 default y
247
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248config POSIX_MQUEUE
249 bool "POSIX Message Queues"
250 depends on NET && EXPERIMENTAL
251 ---help---
252 POSIX variant of message queues is a part of IPC. In POSIX message
253 queues every message has a priority which decides about succession
254 of receiving it by a process. If you want to compile and run
255 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200256 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 POSIX message queues are visible as a filesystem called 'mqueue'
259 and can be mounted somewhere if you want to do filesystem
260 operations on message queues.
261
262 If unsure, say Y.
263
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700264config POSIX_MQUEUE_SYSCTL
265 bool
266 depends on POSIX_MQUEUE
267 depends on SYSCTL
268 default y
269
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530270config FHANDLE
271 bool "open by fhandle syscalls"
272 select EXPORTFS
273 help
274 If you say Y here, a user level program will be able to map
275 file names to handle and then later use the handle for
276 different file system operations. This is useful in implementing
277 userspace file servers, which now track files using handles instead
278 of names. The handle would remain the same even if file names
279 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
280 syscalls.
281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282config AUDIT
283 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100284 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 help
286 Enable auditing infrastructure that can be used with another
287 kernel subsystem, such as SELinux (which requires this for
288 logging of avc messages output). Does not do system-call
289 auditing without CONFIG_AUDITSYSCALL.
290
291config AUDITSYSCALL
292 bool "Enable system-call auditing support"
Will Deacon8f827a12012-07-06 15:48:16 +0100293 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 default y if SECURITY_SELINUX
295 help
296 Enable low-overhead system-call auditing infrastructure that
297 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500298 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
Eric Paris939a67f2009-12-17 20:12:06 -0500300config AUDIT_WATCH
301 def_bool y
302 depends on AUDITSYSCALL
303 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Al Viro74c3cbe2007-07-22 08:04:18 -0400305config AUDIT_TREE
306 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400307 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500308 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400309
Eric Paris633b4542012-01-03 14:23:08 -0500310config AUDIT_LOGINUID_IMMUTABLE
311 bool "Make audit loginuid immutable"
312 depends on AUDIT
313 help
Linus Torvaldsf429ee32012-01-17 16:06:51 -0800314 The config option toggles if a task setting its loginuid requires
Eric Paris633b4542012-01-03 14:23:08 -0500315 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
316 but should instead only allow setting its loginuid if it was never
317 previously set. On systems which use systemd or a similar central
318 process to restart login services this should be set to true. On older
319 systems in which an admin would typically have to directly stop and
320 start processes this should be set to false. Setting this to true allows
321 one to drop potentially dangerous capabilites from the login tasks,
322 but may not be backwards compatible with older init systems.
323
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000324source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200325source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000326
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200327menu "CPU/Task time and stats accounting"
328
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200329choice
330 prompt "Cputime accounting"
331 default TICK_CPU_ACCOUNTING if !PPC64
332 default VIRT_CPU_ACCOUNTING if PPC64
333
334# Kind of a stub config for the pure tick based cputime accounting
335config TICK_CPU_ACCOUNTING
336 bool "Simple tick based cputime accounting"
337 depends on !S390
338 help
339 This is the basic tick based cputime accounting that maintains
340 statistics about user, system and idle time spent on per jiffies
341 granularity.
342
343 If unsure, say Y.
344
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200345config VIRT_CPU_ACCOUNTING
346 bool "Deterministic task and CPU time accounting"
347 depends on HAVE_VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200348 help
349 Select this option to enable more accurate task and CPU time
350 accounting. This is done by reading a CPU counter on each
351 kernel entry and exit and on transitions within the kernel
352 between system, softirq and hardirq state, so there is a
353 small performance impact. In the case of s390 or IBM POWER > 5,
354 this also enables accounting of stolen time on logically-partitioned
355 systems.
356
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200357config IRQ_TIME_ACCOUNTING
358 bool "Fine granularity task level IRQ time accounting"
359 depends on HAVE_IRQ_TIME_ACCOUNTING
360 help
361 Select this option to enable fine granularity task irq time
362 accounting. This is done by reading a timestamp on each
363 transitions between softirq and hardirq state, so there can be a
364 small performance impact.
365
366 If in doubt, say N here.
367
368endchoice
369
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200370config BSD_PROCESS_ACCT
371 bool "BSD Process Accounting"
372 help
373 If you say Y here, a user level program will be able to instruct the
374 kernel (via a special system call) to write process accounting
375 information to a file: whenever a process exits, information about
376 that process will be appended to the file by the kernel. The
377 information includes things such as creation time, owning user,
378 command name, memory usage, controlling terminal etc. (the complete
379 list is in the struct acct in <file:include/linux/acct.h>). It is
380 up to the user level program to do useful things with this
381 information. This is generally a good idea, so say Y.
382
383config BSD_PROCESS_ACCT_V3
384 bool "BSD Process Accounting version 3 file format"
385 depends on BSD_PROCESS_ACCT
386 default n
387 help
388 If you say Y here, the process accounting information is written
389 in a new file format that also logs the process IDs of each
390 process and it's parent. Note that this file format is incompatible
391 with previous v0/v1/v2 file formats, so you will need updated tools
392 for processing it. A preliminary version of these tools is available
393 at <http://www.gnu.org/software/acct/>.
394
395config TASKSTATS
396 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
397 depends on NET
398 default n
399 help
400 Export selected statistics for tasks/processes through the
401 generic netlink interface. Unlike BSD process accounting, the
402 statistics are available during the lifetime of tasks/processes as
403 responses to commands. Like BSD accounting, they are sent to user
404 space on task exit.
405
406 Say N if unsure.
407
408config TASK_DELAY_ACCT
409 bool "Enable per-task delay accounting (EXPERIMENTAL)"
410 depends on TASKSTATS
411 help
412 Collect information on time spent by a task waiting for system
413 resources like cpu, synchronous block I/O completion and swapping
414 in pages. Such statistics can help in setting a task's priorities
415 relative to other tasks for cpu, io, rss limits etc.
416
417 Say N if unsure.
418
419config TASK_XACCT
420 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
421 depends on TASKSTATS
422 help
423 Collect extended task accounting data and send the data
424 to userland for processing over the taskstats interface.
425
426 Say N if unsure.
427
428config TASK_IO_ACCOUNTING
429 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
430 depends on TASK_XACCT
431 help
432 Collect information on the number of bytes of storage I/O which this
433 task has caused.
434
435 Say N if unsure.
436
437endmenu # "CPU/Task time and stats accounting"
438
Mike Travisc903ff82009-01-15 12:28:29 -0800439menu "RCU Subsystem"
440
441choice
442 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700443 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800444
Mike Travisc903ff82009-01-15 12:28:29 -0800445config TREE_RCU
446 bool "Tree-based hierarchical RCU"
Paul E. McKenney687d7a92010-07-21 06:52:40 -0700447 depends on !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800448 help
449 This option selects the RCU implementation that is
450 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700451 thousands of CPUs. It also scales down nicely to
452 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800453
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700454config TREE_PREEMPT_RCU
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700455 bool "Preemptible tree-based hierarchical RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700456 depends on PREEMPT && SMP
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700457 help
458 This option selects the RCU implementation that is
459 designed for very large SMP systems with hundreds or
460 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700461 is also required. It also scales down nicely to
462 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700463
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700464config TINY_RCU
465 bool "UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700466 depends on !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700467 help
468 This option selects the RCU implementation that is
469 designed for UP systems from which real-time response
470 is not required. This option greatly reduces the
471 memory footprint of RCU.
472
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700473config TINY_PREEMPT_RCU
474 bool "Preemptible UP-only small-memory-footprint RCU"
Paul E. McKenney8008e122011-06-08 16:31:33 -0700475 depends on PREEMPT && !SMP
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700476 help
477 This option selects the RCU implementation that is designed
478 for real-time UP systems. This option greatly reduces the
479 memory footprint of RCU.
480
Mike Travisc903ff82009-01-15 12:28:29 -0800481endchoice
482
Paul E. McKenneya57eb942010-06-29 16:49:16 -0700483config PREEMPT_RCU
484 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
485 help
486 This option enables preemptible-RCU code that is common between
487 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
488
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200489config RCU_USER_QS
490 bool "Consider userspace as in RCU extended quiescent state"
491 depends on HAVE_RCU_USER_QS && SMP
492 help
493 This option sets hooks on kernel / userspace boundaries and
494 puts RCU in extended quiescent state when the CPU runs in
495 userspace. It means that when a CPU runs in userspace, it is
496 excluded from the global RCU state machine and thus doesn't
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700497 try to keep the timer tick on for RCU.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200498
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200499 Unless you want to hack and help the development of the full
Paul Gortmakeraf71bef2012-10-24 11:07:09 -0700500 tickless feature, you shouldn't enable this option. It also
501 adds unnecessary overhead.
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200502
503 If unsure say N
504
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200505config RCU_USER_QS_FORCE
506 bool "Force userspace extended QS by default"
507 depends on RCU_USER_QS
508 help
509 Set the hooks in user/kernel boundaries by default in order to
510 test this feature that treats userspace as an extended quiescent
511 state until we have a real user like a full adaptive nohz option.
512
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200513 Unless you want to hack and help the development of the full
514 tickless feature, you shouldn't enable this option. It adds
515 unnecessary overhead.
516
517 If unsure say N
518
Mike Travisc903ff82009-01-15 12:28:29 -0800519config RCU_FANOUT
520 int "Tree-based hierarchical RCU fanout value"
521 range 2 64 if 64BIT
522 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700523 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800524 default 64 if 64BIT
525 default 32 if !64BIT
526 help
527 This option controls the fanout of hierarchical implementations
528 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700529 large numbers of CPUs. This value must be at least the fourth
530 root of NR_CPUS, which allows NR_CPUS to be insanely large.
531 The default value of RCU_FANOUT should be used for production
532 systems, but if you are stress-testing the RCU implementation
533 itself, small RCU_FANOUT values allow you to test large-system
534 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800535
536 Select a specific number if testing RCU itself.
537 Take the default if unsure.
538
Paul E. McKenney8932a632012-04-19 12:20:14 -0700539config RCU_FANOUT_LEAF
540 int "Tree-based hierarchical RCU leaf-level fanout value"
541 range 2 RCU_FANOUT if 64BIT
542 range 2 RCU_FANOUT if !64BIT
543 depends on TREE_RCU || TREE_PREEMPT_RCU
544 default 16
545 help
546 This option controls the leaf-level fanout of hierarchical
547 implementations of RCU, and allows trading off cache misses
548 against lock contention. Systems that synchronize their
549 scheduling-clock interrupts for energy-efficiency reasons will
550 want the default because the smaller leaf-level fanout keeps
551 lock contention levels acceptably low. Very large systems
552 (hundreds or thousands of CPUs) will instead want to set this
553 value to the maximum value possible in order to reduce the
554 number of cache misses incurred during RCU's grace-period
555 initialization. These systems tend to run CPU-bound, and thus
556 are not helped by synchronized interrupts, and thus tend to
557 skew them, which reduces lock contention enough that large
558 leaf-level fanouts work well.
559
560 Select a specific number if testing RCU itself.
561
562 Select the maximum permissible value for large systems.
563
564 Take the default if unsure.
565
Mike Travisc903ff82009-01-15 12:28:29 -0800566config RCU_FANOUT_EXACT
567 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700568 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800569 default n
570 help
571 This option forces use of the exact RCU_FANOUT value specified,
572 regardless of imbalances in the hierarchy. This is useful for
573 testing RCU itself, and might one day be useful on systems with
574 strong NUMA behavior.
575
576 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
577
578 Say N if unsure.
579
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800580config RCU_FAST_NO_HZ
581 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenneyb807fbf2011-11-03 14:56:12 -0700582 depends on NO_HZ && SMP
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800583 default n
584 help
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700585 This option causes RCU to attempt to accelerate grace periods in
586 order to allow CPUs to enter dynticks-idle state more quickly.
587 On the other hand, this option increases the overhead of the
588 dynticks-idle checking, thus degrading scheduling latency.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800589
Paul E. McKenneyba49df42012-10-07 09:26:13 -0700590 Say Y if energy efficiency is critically important, and you don't
591 care about real-time response.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800592
593 Say N if you are unsure.
594
Mike Travisc903ff82009-01-15 12:28:29 -0800595config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700596 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800597 select DEBUG_FS
598 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700599 This option provides tracing for the TREE_RCU and
600 TREE_PREEMPT_RCU implementations, permitting Makefile to
601 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800602
Paul E. McKenney24278d12010-09-27 17:25:23 -0700603config RCU_BOOST
604 bool "Enable RCU priority boosting"
Paul E. McKenney27f4d282011-02-07 12:47:15 -0800605 depends on RT_MUTEXES && PREEMPT_RCU
Paul E. McKenney24278d12010-09-27 17:25:23 -0700606 default n
607 help
608 This option boosts the priority of preempted RCU readers that
609 block the current preemptible RCU grace period for too long.
610 This option also prevents heavy loads from blocking RCU
611 callback invocation for all flavors of RCU.
612
613 Say Y here if you are working with real-time apps or heavy loads
614 Say N here if you are unsure.
615
616config RCU_BOOST_PRIO
617 int "Real-time priority to boost RCU readers to"
618 range 1 99
619 depends on RCU_BOOST
620 default 1
621 help
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700622 This option specifies the real-time priority to which long-term
623 preempted RCU readers are to be boosted. If you are working
624 with a real-time application that has one or more CPU-bound
625 threads running at a real-time priority level, you should set
626 RCU_BOOST_PRIO to a priority higher then the highest-priority
627 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
628 of 1 is appropriate in the common case, which is real-time
629 applications that do not have any CPU-bound threads.
630
631 Some real-time applications might not have a single real-time
632 thread that saturates a given CPU, but instead might have
633 multiple real-time threads that, taken together, fully utilize
634 that CPU. In this case, you should set RCU_BOOST_PRIO to
635 a priority higher than the lowest-priority thread that is
636 conspiring to prevent the CPU from running any non-real-time
637 tasks. For example, if one thread at priority 10 and another
638 thread at priority 5 are between themselves fully consuming
639 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
640 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700641
642 Specify the real-time priority, or take the default if unsure.
643
644config RCU_BOOST_DELAY
645 int "Milliseconds to delay boosting after RCU grace-period start"
646 range 0 3000
647 depends on RCU_BOOST
648 default 500
649 help
650 This option specifies the time to wait after the beginning of
651 a given grace period before priority-boosting preempted RCU
652 readers blocking that grace period. Note that any RCU reader
653 blocking an expedited RCU grace period is boosted immediately.
654
655 Accept the default if unsure.
656
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700657config RCU_NOCB_CPU
658 bool "Offload RCU callback processing from boot-selected CPUs"
659 depends on TREE_RCU || TREE_PREEMPT_RCU
660 default n
661 help
662 Use this option to reduce OS jitter for aggressive HPC or
663 real-time workloads. It can also be used to offload RCU
664 callback invocation to energy-efficient CPUs in battery-powered
665 asymmetric multiprocessors.
666
667 This option offloads callback invocation from the set of
668 CPUs specified at boot time by the rcu_nocbs parameter.
669 For each such CPU, a kthread ("rcuoN") will be created to
670 invoke callbacks, where the "N" is the CPU being offloaded.
671 Nothing prevents this kthread from running on the specified
672 CPUs, but (1) the kthreads may be preempted between each
673 callback, and (2) affinity or cgroups can be used to force
674 the kthreads to run on whatever set of CPUs is desired.
675
676 Say Y here if you want reduced OS jitter on selected CPUs.
677 Say N here if you are unsure.
678
Mike Travisc903ff82009-01-15 12:28:29 -0800679endmenu # "RCU Subsystem"
680
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700682 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 ---help---
684 This option enables the complete Linux kernel ".config" file
685 contents to be saved in the kernel. It provides documentation
686 of which kernel options are used in a running kernel or in an
687 on-disk kernel. This information can be extracted from the kernel
688 image file with the script scripts/extract-ikconfig and used as
689 input to rebuild the current kernel or to build another kernel.
690 It can also be extracted from a running kernel by reading
691 /proc/config.gz if enabled (below).
692
693config IKCONFIG_PROC
694 bool "Enable access to .config through /proc/config.gz"
695 depends on IKCONFIG && PROC_FS
696 ---help---
697 This option enables access to the kernel configuration file
698 through /proc/config.gz.
699
Alistair John Strachan794543a2007-05-08 00:31:15 -0700700config LOG_BUF_SHIFT
701 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
702 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700703 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700704 help
705 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700706 Examples:
707 17 => 128 KB
708 16 => 64 KB
709 15 => 32 KB
710 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700711 13 => 8 KB
712 12 => 4 KB
713
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800714#
715# Architectures with an unreliable sched_clock() should select this:
716#
717config HAVE_UNSTABLE_SCHED_CLOCK
718 bool
719
Li Zefan23964d22009-01-15 13:50:58 -0800720menuconfig CGROUPS
721 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800722 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700723 help
Li Zefan23964d22009-01-15 13:50:58 -0800724 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800725 use with process control subsystems such as Cpusets, CFS, memory
726 controls or device isolation.
727 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800728 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800729 - Documentation/cgroups/ (features for grouping, isolation
730 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700731
732 Say N if unsure.
733
Li Zefan23964d22009-01-15 13:50:58 -0800734if CGROUPS
735
Paul Menage006cb992007-10-18 23:39:43 -0700736config CGROUP_DEBUG
737 bool "Example debug cgroup subsystem"
Paul Menage418d7d82008-04-29 01:00:05 -0700738 default n
Paul Menage006cb992007-10-18 23:39:43 -0700739 help
740 This option enables a simple cgroup subsystem that
741 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800742 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700743
Li Zefan23964d22009-01-15 13:50:58 -0800744 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700745
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700746config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800747 bool "Freezer cgroup subsystem"
Li Zefan23964d22009-01-15 13:50:58 -0800748 help
749 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700750 cgroup.
751
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700752config CGROUP_DEVICE
753 bool "Device controller for cgroups"
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700754 help
755 Provides a cgroup implementing whitelists for devices which
756 a process in the cgroup can mknod or open.
757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758config CPUSETS
759 bool "Cpuset support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700761 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 allow dynamically partitioning a system into sets of CPUs and
763 Memory Nodes and assigning tasks to run only within those sets.
764 This is primarily useful on large SMP or NUMA systems.
765
766 Say N if unsure.
767
Li Zefan23964d22009-01-15 13:50:58 -0800768config PROC_PID_CPUSET
769 bool "Include legacy /proc/<pid>/cpuset file"
770 depends on CPUSETS
771 default y
772
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100773config CGROUP_CPUACCT
774 bool "Simple CPU accounting cgroup subsystem"
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100775 help
776 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800777 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100778
Pavel Emelianove552b662008-02-07 00:13:49 -0800779config RESOURCE_COUNTERS
780 bool "Resource counters"
781 help
782 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800783 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800784
Andrew Mortonc255a452012-07-31 16:43:02 -0700785config MEMCG
Balbir Singh00f0b822008-03-04 14:28:39 -0800786 bool "Memory Resource Controller for Control Groups"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700787 depends on RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700788 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800789 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700790 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100791 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800792
793 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700794 associated with each page of memory in the system. By this,
795 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
796 usage tracking struct at boot. Total amount of this is printed out
797 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800798
799 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700800 sure you need the memory resource controller. Even when you enable
801 this, you can set "cgroup_disable=memory" at your boot option to
802 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800803 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800804
Balbir Singhcf475ad2008-04-29 01:00:16 -0700805 This config option also selects MM_OWNER config option, which
806 could in turn add some fork/exit overhead.
807
Andrew Mortonc255a452012-07-31 16:43:02 -0700808config MEMCG_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700809 bool "Memory Resource Controller Swap Extension"
Andrew Mortonc255a452012-07-31 16:43:02 -0700810 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800811 help
812 Add swap management feature to memory resource controller. When you
813 enable this, you can limit mem+swap usage per cgroup. In other words,
814 when you disable this, memory resource controller has no cares to
815 usage of swap...a process can exhaust all of the swap. This extension
816 is useful when you want to avoid exhaustion swap but this itself
817 adds more overheads and consumes memory for remembering information.
818 Especially if you use 32bit system or small memory system, please
819 be careful about enabling this. When memory resource controller
820 is disabled by boot option, this will be automatically disabled and
821 there will be no overhead from this. Even when you set this config=y,
WANG Cong00a66d22011-07-25 17:12:12 -0700822 if boot option "swapaccount=0" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700823 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
824 size is 4096bytes, 512k per 1Gbytes of swap.
Andrew Mortonc255a452012-07-31 16:43:02 -0700825config MEMCG_SWAP_ENABLED
Michal Hockoa42c3902010-11-24 12:57:08 -0800826 bool "Memory Resource Controller Swap Extension enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700827 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800828 default y
829 help
830 Memory Resource Controller Swap Extension comes with its price in
831 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700832 which want to enable the feature but keep it disabled by default
Michal Hockoa42c3902010-11-24 12:57:08 -0800833 and let the user enable it by swapaccount boot command line
834 parameter should have this option unselected.
835 For those who want to have the feature enabled by default should
836 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700837 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700838config MEMCG_KMEM
Glauber Costae5671df2011-12-11 21:47:01 +0000839 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
Andrew Mortonc255a452012-07-31 16:43:02 -0700840 depends on MEMCG && EXPERIMENTAL
Glauber Costae5671df2011-12-11 21:47:01 +0000841 default n
842 help
843 The Kernel Memory extension for Memory Resource Controller can limit
844 the amount of memory used by kernel objects in the system. Those are
845 fundamentally different from the entities handled by the standard
846 Memory Controller, which are page-based, and can be swapped. Users of
847 the kmem extension can use it to guarantee that no group of processes
848 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800849
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700850config CGROUP_HUGETLB
851 bool "HugeTLB Resource Controller for Control Groups"
852 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
853 default n
854 help
855 Provides a cgroup Resource Controller for HugeTLB pages.
856 When you enable this, you can put a per cgroup limit on HugeTLB usage.
857 The limit is enforced during page fault. Since HugeTLB doesn't
858 support page reclaim, enforcing the limit at page fault time implies
859 that, the application will get SIGBUS signal if it tries to access
860 HugeTLB pages beyond its limit. This requires the application to know
861 beforehand how much HugeTLB pages it would require for its use. The
862 control group is tracked in the third page lru pointer. This means
863 that we cannot use the controller with huge page less than 3 pages.
864
Stephane Eraniane5d13672011-02-14 11:20:01 +0200865config CGROUP_PERF
866 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
867 depends on PERF_EVENTS && CGROUPS
868 help
869 This option extends the per-cpu mode to restrict monitoring to
Li Zefan2d0f2522011-03-03 14:26:20 +0800870 threads which belong to the cgroup specified and run on the
Stephane Eraniane5d13672011-02-14 11:20:01 +0200871 designated cpu.
872
873 Say N if unsure.
874
Dhaval Giani7c941432010-01-20 13:26:18 +0100875menuconfig CGROUP_SCHED
876 bool "Group CPU scheduler"
Dhaval Giani7c941432010-01-20 13:26:18 +0100877 default n
878 help
879 This feature lets CPU scheduler recognize task groups and control CPU
880 bandwidth allocation to such task groups. It uses cgroups to group
881 tasks.
882
883if CGROUP_SCHED
884config FAIR_GROUP_SCHED
885 bool "Group scheduling for SCHED_OTHER"
886 depends on CGROUP_SCHED
887 default CGROUP_SCHED
888
Paul Turnerab84d312011-07-21 09:43:28 -0700889config CFS_BANDWIDTH
890 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
891 depends on EXPERIMENTAL
892 depends on FAIR_GROUP_SCHED
893 default n
894 help
895 This option allows users to define CPU bandwidth rates (limits) for
896 tasks running within the fair group scheduler. Groups with no limit
897 set are considered to be unconstrained and will run with no
898 restriction.
899 See tip/Documentation/scheduler/sched-bwc.txt for more information.
900
Dhaval Giani7c941432010-01-20 13:26:18 +0100901config RT_GROUP_SCHED
902 bool "Group scheduling for SCHED_RR/FIFO"
903 depends on EXPERIMENTAL
904 depends on CGROUP_SCHED
905 default n
906 help
907 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800908 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100909 schedule realtime tasks for non-root users until you allocate
910 realtime bandwidth for them.
911 See Documentation/scheduler/sched-rt-group.txt for more information.
912
913endif #CGROUP_SCHED
914
Vivek Goyalafc24d42010-04-26 19:27:56 +0200915config BLK_CGROUP
Tejun Heo32e380a2012-03-05 13:14:54 -0800916 bool "Block IO controller"
Daniel Lezcano79ae9c22010-10-27 15:34:39 -0700917 depends on BLOCK
Vivek Goyalafc24d42010-04-26 19:27:56 +0200918 default n
919 ---help---
920 Generic block IO controller cgroup interface. This is the common
921 cgroup interface which should be used by various IO controlling
922 policies.
923
924 Currently, CFQ IO scheduler uses it to recognize task groups and
925 control disk bandwidth allocation (proportional time slice allocation)
Vivek Goyale43473b2010-09-15 17:06:35 -0400926 to such task groups. It is also used by bio throttling logic in
927 block layer to implement upper limit in IO rates on a device.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200928
929 This option only enables generic Block IO controller infrastructure.
Vivek Goyale43473b2010-09-15 17:06:35 -0400930 One needs to also enable actual IO controlling logic/policy. For
Michael Witten79e2e752011-01-16 21:43:10 +0000931 enabling proportional weight division of disk bandwidth in CFQ, set
932 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Michael Wittenc5e05912011-01-17 00:08:41 +0000933 CONFIG_BLK_DEV_THROTTLING=y.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200934
935 See Documentation/cgroups/blkio-controller.txt for more information.
936
937config DEBUG_BLK_CGROUP
938 bool "Enable Block IO controller debugging"
939 depends on BLK_CGROUP
940 default n
941 ---help---
942 Enable some debugging help. Currently it exports additional stat
943 files in a cgroup which can be useful for debugging.
944
Li Zefan23964d22009-01-15 13:50:58 -0800945endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800946
Cyrill Gorcunov067bce12012-01-12 17:20:49 -0800947config CHECKPOINT_RESTORE
948 bool "Checkpoint/restore support" if EXPERT
949 default n
950 help
951 Enables additional kernel features in a sake of checkpoint/restore.
952 In particular it adds auxiliary prctl codes to setup process text,
953 data and heap segment sizes, and a few additional /proc filesystem
954 entries.
955
956 If unsure, say N here.
957
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700958menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800959 bool "Namespaces support" if EXPERT
960 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800961 help
962 Provides the way to make tasks work with different objects using
963 the same id. For example same IPC id may refer to different objects
964 or same user id or pid may refer to different tasks when used in
965 different namespaces.
966
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700967if NAMESPACES
968
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800969config UTS_NS
970 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700971 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800972 help
973 In this namespace tasks see different info provided with the
974 uname() system call
975
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800976config IPC_NS
977 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700978 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700979 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800980 help
981 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700982 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800983
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800984config USER_NS
985 bool "User namespace (EXPERIMENTAL)"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700986 depends on EXPERIMENTAL
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700987 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -0800988 select UIDGID_STRICT_TYPE_CHECKS
Eric W. Biedermane1c972b2012-04-21 04:09:01 -0700989
Eric W. Biederman5673a942011-11-17 10:23:55 -0800990 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800991 help
992 This allows containers, i.e. vservers, to use user namespaces
993 to provide different user info for different servers.
994 If unsure, say N.
995
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800996config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700997 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700998 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800999 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001000 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001001 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001002 pid namespaces. This is a building block of containers.
1003
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001004config NET_NS
1005 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001006 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001007 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001008 help
1009 Allow user space to create what appear to be multiple instances
1010 of the network stack.
1011
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001012endif # NAMESPACES
1013
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001014config UIDGID_CONVERTED
1015 # True if all of the selected software conmponents are known
1016 # to have uid_t and gid_t converted to kuid_t and kgid_t
1017 # where appropriate and are otherwise safe to use with
1018 # the user namespace.
1019 bool
1020 default y
1021
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001022 # Networking
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001023 depends on NET_9P = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001024
1025 # Filesystems
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001026 depends on 9P_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001027 depends on AFS_FS = n
1028 depends on AUTOFS4_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001029 depends on CEPH_FS = n
1030 depends on CIFS = n
1031 depends on CODA_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001032 depends on FUSE_FS = n
1033 depends on GFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001034 depends on NCP_FS = n
1035 depends on NFSD = n
1036 depends on NFS_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001037 depends on OCFS2_FS = n
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001038 depends on XFS_FS = n
1039
Eric W. Biederman5673a942011-11-17 10:23:55 -08001040config UIDGID_STRICT_TYPE_CHECKS
1041 bool "Require conversions between uid/gids and their internal representation"
Eric W. Biedermane1c972b2012-04-21 04:09:01 -07001042 depends on UIDGID_CONVERTED
Eric W. Biederman5673a942011-11-17 10:23:55 -08001043 default n
1044 help
1045 While the nececessary conversions are being added to all subsystems this option allows
1046 the code to continue to build for unconverted subsystems.
1047
1048 Say Y here if you want the strict type checking enabled
1049
Mike Galbraith5091faa2010-11-30 14:18:03 +01001050config SCHED_AUTOGROUP
1051 bool "Automatic process group scheduling"
1052 select EVENTFD
1053 select CGROUPS
1054 select CGROUP_SCHED
1055 select FAIR_GROUP_SCHED
1056 help
1057 This option optimizes the scheduler for common desktop workloads by
1058 automatically creating and populating task groups. This separation
1059 of workloads isolates aggressive CPU burners (like build jobs) from
1060 desktop applications. Task group autogeneration is currently based
1061 upon task session.
1062
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001063config MM_OWNER
1064 bool
1065
1066config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001067 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001068 depends on SYSFS
1069 default n
1070 help
1071 This option adds code that switches the layout of the "block" class
1072 devices, to not show up in /sys/class/block/, but only in
1073 /sys/block/.
1074
1075 This switch is only active when the sysfs.deprecated=1 boot option is
1076 passed or the SYSFS_DEPRECATED_V2 option is set.
1077
1078 This option allows new kernels to run on old distributions and tools,
1079 which might get confused by /sys/class/block/. Since 2007/2008 all
1080 major distributions and tools handle this just fine.
1081
1082 Recent distributions and userspace tools after 2009/2010 depend on
1083 the existence of /sys/class/block/, and will not work with this
1084 option enabled.
1085
1086 Only if you are using a new kernel on an old distribution, you might
1087 need to say Y here.
1088
1089config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001090 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001091 default n
1092 depends on SYSFS
1093 depends on SYSFS_DEPRECATED
1094 help
1095 Enable deprecated sysfs by default.
1096
1097 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1098 option.
1099
1100 Only if you are using a new kernel on an old distribution, you might
1101 need to say Y here. Even then, odds are you would not need it
1102 enabled, you can always pass the boot option if absolutely necessary.
1103
1104config RELAY
1105 bool "Kernel->user space relay support (formerly relayfs)"
1106 help
1107 This option enables support for relay interface support in
1108 certain file systems (such as debugfs).
1109 It is designed to provide an efficient mechanism for tools and
1110 facilities to relay large amounts of data from kernel space to
1111 user space.
1112
1113 If unsure, say N.
1114
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001115config BLK_DEV_INITRD
1116 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1117 depends on BROKEN || !FRV
1118 help
1119 The initial RAM filesystem is a ramfs which is loaded by the
1120 boot loader (loadlin or lilo) and that is mounted as root
1121 before the normal boot procedure. It is typically used to
1122 load modules needed to mount the "real" root file system,
1123 etc. See <file:Documentation/initrd.txt> for details.
1124
1125 If RAM disk support (BLK_DEV_RAM) is also included, this
1126 also enables initial RAM disk (initrd) support and adds
1127 15 Kbytes (more on some other architectures) to the kernel size.
1128
1129 If unsure say Y.
1130
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001131if BLK_DEV_INITRD
1132
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001133source "usr/Kconfig"
1134
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001135endif
1136
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001137config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001138 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001139 help
1140 Enabling this option will pass "-Os" instead of "-O2" to gcc
1141 resulting in a smaller kernel.
1142
jkacur775a7222008-07-16 00:31:16 +02001143 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001144
Randy Dunlap08470622006-09-30 23:28:13 -07001145config SYSCTL
1146 bool
1147
Randy Dunlapb943c462009-03-10 12:55:46 -07001148config ANON_INODES
1149 bool
1150
David Rientjes6a108a12011-01-20 14:44:16 -08001151menuconfig EXPERT
1152 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001153 # Unhide debug options, to make the on-by-default options visible
1154 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 help
1156 This option allows certain base kernel options and settings
1157 to be disabled or tweaked. This is for specialized
1158 environments which can tolerate a "non-standard" kernel.
1159 Only use this if you really know what you are doing.
1160
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001161config HAVE_UID16
1162 bool
1163
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001164config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001165 bool "Enable 16-bit UID system calls" if EXPERT
Catalin Marinasaf1839e2012-10-08 16:28:08 -07001166 depends on HAVE_UID16
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001167 default y
1168 help
1169 This enables the legacy 16-bit UID syscall wrappers.
1170
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001171config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001172 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001173 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001174 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001175 select SYSCTL
1176 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001177 sys_sysctl uses binary paths that have been found challenging
1178 to properly maintain and use. The interface in /proc/sys
1179 using paths with ascii names is now the primary path to this
1180 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001181
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001182 Almost nothing using the binary sysctl interface so if you are
1183 trying to save some space it is probably safe to disable this,
1184 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001185
WANG Congc736de62011-11-02 13:39:25 -07001186 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001187
Catalin Marinas7ac57a82012-10-08 16:28:16 -07001188config SYSCTL_EXCEPTION_TRACE
1189 bool
1190 help
1191 Enable support for /proc/sys/debug/exception-trace.
1192
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001194 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 default y
1196 help
1197 Say Y here to let the kernel print out symbolic crash information and
1198 symbolic stack backtraces. This increases the size of the kernel
1199 somewhat, as all symbols have to be loaded into the kernel image.
1200
1201config KALLSYMS_ALL
1202 bool "Include all symbols in kallsyms"
1203 depends on DEBUG_KERNEL && KALLSYMS
1204 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001205 Normally kallsyms only contains the symbols of functions for nicer
1206 OOPS messages and backtraces (i.e., symbols from the text and inittext
1207 sections). This is sufficient for most cases. And only in very rare
1208 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1209 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001211 This option makes sure that all symbols are loaded into the kernel
1212 image (i.e., symbols from all sections) in cost of increased kernel
1213 size (depending on the kernel configuration, it may be 300KiB or
1214 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001216 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001217
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001218config HOTPLUG
Greg Kroah-Hartman45f035a2012-09-04 17:01:08 -07001219 def_bool y
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -08001220
Matt Mackalld59745c2005-05-01 08:59:02 -07001221config PRINTK
1222 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001223 bool "Enable support for printk" if EXPERT
Matt Mackalld59745c2005-05-01 08:59:02 -07001224 help
1225 This option enables normal printk support. Removing it
1226 eliminates most of the message strings from the kernel image
1227 and makes the kernel more or less silent. As this makes it
1228 very difficult to diagnose system problems, saying N here is
1229 strongly discouraged.
1230
Matt Mackallc8538a72005-05-01 08:59:01 -07001231config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001232 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001233 default y
1234 help
1235 Disabling this option eliminates support for BUG and WARN, reducing
1236 the size of your kernel image and potentially quietly ignoring
1237 numerous fatal conditions. You should only consider disabling this
1238 option for embedded systems with no facilities for reporting errors.
1239 Just say Y.
1240
Matt Mackall708e9a72006-01-08 01:05:25 -08001241config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001242 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001243 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001244 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001245 help
1246 Enable support for generating core dumps. Disabling saves about 4k.
1247
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001248
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001249config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001250 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001251 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001252 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001253 default y
1254 help
1255 This option allows to disable the internal PC-Speaker
1256 support, saving some memory.
1257
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001258config HAVE_PCSPKR_PLATFORM
1259 bool
1260
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261config BASE_FULL
1262 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001263 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 help
1265 Disabling this option reduces the size of miscellaneous core
1266 kernel data structures. This saves memory on small machines,
1267 but may reduce performance.
1268
1269config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001270 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001272 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 help
1274 Disabling this option will cause the kernel to be built without
1275 support for "fast userspace mutexes". The resulting kernel may not
1276 run glibc-based applications correctly.
1277
1278config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001279 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001281 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 help
1283 Disabling this option will cause the kernel to be built without
1284 support for epoll family of system calls.
1285
Davide Libenzifba2afa2007-05-10 22:23:13 -07001286config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001287 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001288 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001289 default y
1290 help
1291 Enable the signalfd() system call that allows to receive signals
1292 on a file descriptor.
1293
1294 If unsure, say Y.
1295
Davide Libenzib215e282007-05-10 22:23:16 -07001296config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001297 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001298 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001299 default y
1300 help
1301 Enable the timerfd() system call that allows to receive timer
1302 events on a file descriptor.
1303
1304 If unsure, say Y.
1305
Davide Libenzie1ad7462007-05-10 22:23:19 -07001306config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001307 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001308 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001309 default y
1310 help
1311 Enable the eventfd() system call that allows to receive both
1312 kernel notification (ie. KAIO) or userspace notifications.
1313
1314 If unsure, say Y.
1315
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001317 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 default y
1319 depends on MMU
1320 help
1321 The shmem is an internal filesystem used to manage shared memory.
1322 It is backed by swap and manages resource limits. It is also exported
1323 to userspace as tmpfs if TMPFS is enabled. Disabling this
1324 option replaces shmem and tmpfs with the much simpler ramfs code,
1325 which may be appropriate on small systems without swap.
1326
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001327config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001328 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001329 default y
1330 help
1331 This option enables POSIX asynchronous I/O which may by used
1332 by some high performance threaded applications. Disabling
1333 this option saves about 7k.
1334
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001335config EMBEDDED
1336 bool "Embedded system"
1337 select EXPERT
1338 help
1339 This option should be enabled if compiling the kernel for
1340 an embedded system so certain expert options are available
1341 for configuration.
1342
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001343config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001344 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001345 help
1346 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001347
Peter Zijlstra906010b2009-09-21 16:08:49 +02001348config PERF_USE_VMALLOC
1349 bool
1350 help
1351 See tools/perf/design.txt for details
1352
Ingo Molnar57c0c152009-09-21 12:20:38 +02001353menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001354
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001355config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001356 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001357 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001358 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001359 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001360 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001361 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001362 Enable kernel support for various performance events provided
1363 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001364
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001365 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001366 use of generic tracepoints.
1367
1368 Most modern CPUs support performance events via performance
1369 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001370 types of hw events: such as instructions executed, cachemisses
1371 suffered, or branches mis-predicted - without slowing down the
1372 kernel or applications. These registers can also trigger interrupts
1373 when a threshold number of events have passed - and can thus be
1374 used to profile the code that runs on that CPU.
1375
Ingo Molnar57c0c152009-09-21 12:20:38 +02001376 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001377 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001378 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001379 provides per task and per CPU counters, and it provides event
1380 capabilities on top of those.
1381
1382 Say Y if unsure.
1383
Peter Zijlstra906010b2009-09-21 16:08:49 +02001384config DEBUG_PERF_USE_VMALLOC
1385 default n
1386 bool "Debug: use vmalloc to back perf mmap() buffers"
1387 depends on PERF_EVENTS && DEBUG_KERNEL
1388 select PERF_USE_VMALLOC
1389 help
1390 Use vmalloc memory to back perf mmap() buffers.
1391
1392 Mostly useful for debugging the vmalloc code on platforms
1393 that don't require it.
1394
1395 Say N if unsure.
1396
Thomas Gleixner0793a612008-12-04 20:12:29 +01001397endmenu
1398
Christoph Lameterf8891e52006-06-30 01:55:45 -07001399config VM_EVENT_COUNTERS
1400 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001401 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001402 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001403 VM event counters are needed for event counts to be shown.
1404 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001405 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001406 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001407
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001408config PCI_QUIRKS
1409 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001410 bool "Enable PCI quirk workarounds" if EXPERT
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001411 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001412 help
1413 This enables workarounds for various PCI chipset
1414 bugs/quirks. Disable this only if your target machine is
1415 unaffected by PCI quirks.
1416
Christoph Lameter41ecc552007-05-09 02:32:44 -07001417config SLUB_DEBUG
1418 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001419 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001420 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001421 help
1422 SLUB has extensive debug support features. Disabling these can
1423 result in significant savings in code size. This also disables
1424 SLUB sysfs support. /sys/slab will not exist and there will be
1425 no support for cache validation etc.
1426
Randy Dunlapb943c462009-03-10 12:55:46 -07001427config COMPAT_BRK
1428 bool "Disable heap randomization"
1429 default y
1430 help
1431 Randomizing heap placement makes heap exploits harder, but it
1432 also breaks ancient binaries (including anything libc5 based).
1433 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001434 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001435 /proc/sys/kernel/randomize_va_space to 2.
1436
1437 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1438
Christoph Lameter81819f02007-05-06 14:49:36 -07001439choice
1440 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001441 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001442 help
1443 This option allows to select a slab allocator.
1444
1445config SLAB
1446 bool "SLAB"
1447 help
1448 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001449 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001450 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001451
1452config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001453 bool "SLUB (Unqueued Allocator)"
1454 help
1455 SLUB is a slab allocator that minimizes cache line usage
1456 instead of managing queues of cached objects (SLAB approach).
1457 Per cpu caching is realized using slabs of objects instead
1458 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001459 and has enhanced diagnostics. SLUB is the default choice for
1460 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001461
1462config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001463 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001464 bool "SLOB (Simple Allocator)"
1465 help
Matt Mackall37291452008-02-04 22:29:38 -08001466 SLOB replaces the stock allocator with a drastically simpler
1467 allocator. SLOB is generally more space efficient but
1468 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001469
1470endchoice
1471
Jie Zhangea637632009-12-14 18:00:02 -08001472config MMAP_ALLOW_UNINITIALIZED
1473 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001474 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001475 default n
1476 help
1477 Normally, and according to the Linux spec, anonymous memory obtained
1478 from mmap() has it's contents cleared before it is passed to
1479 userspace. Enabling this config option allows you to request that
1480 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1481 providing a huge performance boost. If this option is not enabled,
1482 then the flag will be ignored.
1483
1484 This is taken advantage of by uClibc's malloc(), and also by
1485 ELF-FDPIC binfmt's brk and stack allocator.
1486
1487 Because of the obvious security issues, this option should only be
1488 enabled on embedded devices where you control what is run in
1489 userspace. Since that isn't generally a problem on no-MMU systems,
1490 it is normally safe to say Y here.
1491
1492 See Documentation/nommu-mmap.txt for more information.
1493
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001494config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001495 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001496 help
1497 Say Y here to enable the extended profiling support mechanisms used
1498 by profilers such as OProfile.
1499
Ingo Molnar5f87f112008-07-23 14:15:22 +02001500#
1501# Place an empty function call at each tracepoint site. Can be
1502# dynamically changed for a probe function.
1503#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001504config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001505 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001506
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001507source "arch/Kconfig"
1508
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509endmenu # General setup
1510
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001511config HAVE_GENERIC_DMA_COHERENT
1512 bool
1513 default n
1514
Linus Torvalds158a9622008-01-02 13:04:48 -08001515config SLABINFO
1516 bool
1517 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001518 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001519 default y
1520
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001521config RT_MUTEXES
1522 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001523
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524config BASE_SMALL
1525 int
1526 default 0 if BASE_FULL
1527 default 1 if !BASE_FULL
1528
Jan Engelhardt66da5732007-07-15 23:39:29 -07001529menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 bool "Enable loadable module support"
1531 help
1532 Kernel modules are small pieces of compiled code which can
1533 be inserted in the running kernel, rather than being
1534 permanently built into the kernel. You use the "modprobe"
1535 tool to add (and sometimes remove) them. If you say Y here,
1536 many parts of the kernel can be built as modules (by
1537 answering M instead of Y where indicated): this is most
1538 useful for infrequently used options which are not required
1539 for booting. For more information, see the man pages for
1540 modprobe, lsmod, modinfo, insmod and rmmod.
1541
1542 If you say Y here, you will need to run "make
1543 modules_install" to put the modules under /lib/modules/
1544 where modprobe can find them (you may need to be root to do
1545 this).
1546
1547 If unsure, say Y.
1548
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001549if MODULES
1550
Linus Torvalds826e4502008-05-04 17:04:16 -07001551config MODULE_FORCE_LOAD
1552 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001553 default n
1554 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001555 Allow loading of modules without version information (ie. modprobe
1556 --force). Forced module loading sets the 'F' (forced) taint flag and
1557 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001558
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559config MODULE_UNLOAD
1560 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 help
1562 Without this option you will not be able to unload any
1563 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001564 anyway), which makes your kernel smaller, faster
1565 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566
1567config MODULE_FORCE_UNLOAD
1568 bool "Forced module unloading"
1569 depends on MODULE_UNLOAD && EXPERIMENTAL
1570 help
1571 This option allows you to force a module to unload, even if the
1572 kernel believes it is unsafe: the kernel will remove the module
1573 without waiting for anyone to stop using it (using the -f option to
1574 rmmod). This is mainly for kernel developers and desperate users.
1575 If unsure, say N.
1576
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001578 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579 help
1580 Usually, you have to use modules compiled with your kernel.
1581 Saying Y here makes it sometimes possible to use modules
1582 compiled for different kernels, by adding enough information
1583 to the modules to (hopefully) spot any changes which would
1584 make them incompatible with the kernel you are running. If
1585 unsure, say N.
1586
1587config MODULE_SRCVERSION_ALL
1588 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 help
1590 Modules which contain a MODULE_VERSION get an extra "srcversion"
1591 field inserted into their modinfo section, which contains a
1592 sum of the source files which made it. This helps maintainers
1593 see exactly which source was used to build a module (since
1594 others sometimes change the module source without updating
1595 the version). With this option, such a "srcversion" field
1596 will be created for all modules. If unsure, say N.
1597
Rusty Russell106a4ee2012-09-26 10:09:40 +01001598config MODULE_SIG
1599 bool "Module signature verification"
1600 depends on MODULES
David Howells48ba2462012-09-26 10:11:03 +01001601 select KEYS
1602 select CRYPTO
1603 select ASYMMETRIC_KEY_TYPE
1604 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1605 select PUBLIC_KEY_ALGO_RSA
1606 select ASN1
1607 select OID_REGISTRY
1608 select X509_CERTIFICATE_PARSER
Rusty Russell106a4ee2012-09-26 10:09:40 +01001609 help
1610 Check modules for valid signatures upon load: the signature
1611 is simply appended to the module. For more information see
1612 Documentation/module-signing.txt.
1613
David Howellsea0b6dc2012-09-26 10:09:50 +01001614 !!!WARNING!!! If you enable this option, you MUST make sure that the
1615 module DOES NOT get stripped after being signed. This includes the
1616 debuginfo strip done by some packagers (such as rpmbuild) and
1617 inclusion into an initramfs that wants the module size reduced.
1618
Rusty Russell106a4ee2012-09-26 10:09:40 +01001619config MODULE_SIG_FORCE
1620 bool "Require modules to be validly signed"
1621 depends on MODULE_SIG
1622 help
1623 Reject unsigned modules or signed modules for which we don't have a
1624 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001625
1626choice
1627 prompt "Which hash algorithm should modules be signed with?"
1628 depends on MODULE_SIG
1629 help
1630 This determines which sort of hashing algorithm will be used during
1631 signature generation. This algorithm _must_ be built into the kernel
1632 directly so that signature verification can take place. It is not
1633 possible to load a signed module containing the algorithm to check
1634 the signature on that module.
1635
1636config MODULE_SIG_SHA1
1637 bool "Sign modules with SHA-1"
1638 select CRYPTO_SHA1
1639
1640config MODULE_SIG_SHA224
1641 bool "Sign modules with SHA-224"
1642 select CRYPTO_SHA256
1643
1644config MODULE_SIG_SHA256
1645 bool "Sign modules with SHA-256"
1646 select CRYPTO_SHA256
1647
1648config MODULE_SIG_SHA384
1649 bool "Sign modules with SHA-384"
1650 select CRYPTO_SHA512
1651
1652config MODULE_SIG_SHA512
1653 bool "Sign modules with SHA-512"
1654 select CRYPTO_SHA512
1655
1656endchoice
1657
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001658endif # MODULES
1659
Rusty Russell98a79d62008-12-13 21:19:41 +10301660config INIT_ALL_POSSIBLE
1661 bool
1662 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301663 Back when each arch used to define their own cpu_online_mask and
1664 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301665 with all 1s, and others with all 0s. When they were centralised,
1666 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001667 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301668
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669config STOP_MACHINE
1670 bool
1671 default y
1672 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1673 help
1674 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001675
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001676source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001677
1678config PREEMPT_NOTIFIERS
1679 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001680
Steffen Klassert16295be2010-01-06 19:47:10 +11001681config PADATA
1682 depends on SMP
1683 bool
1684
Andi Kleen754b7b62012-10-04 17:11:27 -07001685# Can be selected by architectures with broken toolchains
1686# that get confused by correct const<->read_only section
1687# mappings
1688config BROKEN_RODATA
1689 bool
1690
David Howells4520c6a2012-09-21 23:31:13 +01001691config ASN1
1692 tristate
1693 help
1694 Build a simple ASN.1 grammar compiler that produces a bytecode output
1695 that can be interpreted by the ASN.1 stream decoder and used to
1696 inform it as to what tags are to be expected in a stream and what
1697 functions to call on what tags.
1698
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001699source "kernel/Kconfig.locks"