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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' Giarrussob2670ea2006-10-19 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
22 default y
23
Al Boldiff0cfc62007-07-31 00:39:23 -070024menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26config EXPERIMENTAL
27 bool "Prompt for development and/or incomplete code/drivers"
28 ---help---
29 Some of the various things that Linux supports (such as network
30 drivers, file systems, network protocols, etc.) can be in a state
31 of development where the functionality, stability, or the level of
32 testing is not yet high enough for general use. This is usually
33 known as the "alpha-test" phase among developers. If a feature is
34 currently in alpha-test, then the developers usually discourage
35 uninformed widespread use of this feature by the general public to
36 avoid "Why doesn't this work?" type mail messages. However, active
37 testing and use of these systems is welcomed. Just be aware that it
38 may not meet the normal level of reliability or it may fail to work
39 in some special cases. Detailed bug reports from people familiar
40 with the kernel internals are usually welcomed by the developers
41 (before submitting bug reports, please read the documents
42 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
43 <file:Documentation/BUG-HUNTING>, and
44 <file:Documentation/oops-tracing.txt> in the kernel source).
45
46 This option will also make obsoleted drivers available. These are
47 drivers that have been replaced by something else, and/or are
48 scheduled to be removed in a future kernel release.
49
50 Unless you intend to help test and develop a feature or driver that
51 falls into this category, or you have a situation that requires
52 using these features, you should probably say N here, which will
53 cause the configurator to present you with fewer choices. If
54 you say Y here, you will be offered the choice of using features or
55 drivers that are currently considered to be in the alpha-test phase.
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057config BROKEN
58 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60config BROKEN_ON_SMP
61 bool
62 depends on BROKEN || !SMP
63 default y
64
65config LOCK_KERNEL
66 bool
67 depends on SMP || PREEMPT
68 default y
69
70config INIT_ENV_ARG_LIMIT
71 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070072 default 32 if !UML
73 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080075 Maximum of each of the number of arguments and environment
76 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79config LOCALVERSION
80 string "Local version - append to kernel release"
81 help
82 Append an extra string to the end of your kernel version.
83 This will show up when you type uname, for example.
84 The string you set here will be appended after the contents of
85 any files with a filename matching localversion* in your
86 object and source tree, in that order. Your total string can
87 be a maximum of 64 characters.
88
Ryan Andersonaaebf432005-07-31 04:57:49 -040089config LOCALVERSION_AUTO
90 bool "Automatically append version information to the version string"
91 default y
92 help
93 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020094 release tree by looking for git tags that belong to the current
95 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040096
97 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020098 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040099 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200100 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400101
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200102 (The actual string used here is the first eight characters produced
103 by running the command:
104
105 $ git rev-parse --verify HEAD
106
107 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400108
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800109config HAVE_KERNEL_GZIP
110 bool
111
112config HAVE_KERNEL_BZIP2
113 bool
114
115config HAVE_KERNEL_LZMA
116 bool
117
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800118config HAVE_KERNEL_LZO
119 bool
120
Alain Knaff30d65db2009-01-04 22:46:17 +0100121choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800122 prompt "Kernel compression mode"
123 default KERNEL_GZIP
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800124 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800125 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100126 The linux kernel is a kind of self-extracting executable.
127 Several compression algorithms are available, which differ
128 in efficiency, compression and decompression speed.
129 Compression speed is only relevant when building a kernel.
130 Decompression speed is relevant at each boot.
131
132 If you have any problems with bzip2 or lzma compressed
133 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
134 version of this functionality (bzip2 only), for 2.4, was
135 supplied by Christian Ludwig)
136
137 High compression options are mostly useful for users, who
138 are low on disk space (embedded systems), but for whom ram
139 size matters less.
140
141 If in doubt, select 'gzip'
142
143config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800144 bool "Gzip"
145 depends on HAVE_KERNEL_GZIP
146 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800147 The old and tried gzip compression. It provides a good balance
148 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100149
150config KERNEL_BZIP2
151 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800152 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100153 help
154 Its compression ratio and speed is intermediate.
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800155 Decompression speed is slowest among the three. The kernel
156 size is about 10% smaller with bzip2, in comparison to gzip.
157 Bzip2 uses a large amount of memory. For modern kernels you
158 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100159
160config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800161 bool "LZMA"
162 depends on HAVE_KERNEL_LZMA
163 help
164 The most recent compression algorithm.
165 Its ratio is best, decompression speed is between the other
166 two. Compression is slowest. The kernel size is about 33%
167 smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100168
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800169config KERNEL_LZO
170 bool "LZO"
171 depends on HAVE_KERNEL_LZO
172 help
173 Its compression ratio is the poorest among the 4. The kernel
174 size is about about 10% bigger than gzip; however its speed
175 (both compression and decompression) is the fastest.
176
Alain Knaff30d65db2009-01-04 22:46:17 +0100177endchoice
178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179config SWAP
180 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200181 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 default y
183 help
184 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100185 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 used to provide more virtual memory than the actual RAM present
187 in your computer. If unsure say Y.
188
189config SYSVIPC
190 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 ---help---
192 Inter Process Communication is a suite of library functions and
193 system calls which let processes (running programs) synchronize and
194 exchange information. It is generally considered to be a good thing,
195 and some programs won't run unless you say Y here. In particular, if
196 you want to run the DOS emulator dosemu under Linux (read the
197 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
198 you'll need to say Y here.
199
200 You can find documentation about IPC with "info ipc" and also in
201 section 6.4 of the Linux Programmer's Guide, available from
202 <http://www.tldp.org/guides.html>.
203
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800204config SYSVIPC_SYSCTL
205 bool
206 depends on SYSVIPC
207 depends on SYSCTL
208 default y
209
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210config POSIX_MQUEUE
211 bool "POSIX Message Queues"
212 depends on NET && EXPERIMENTAL
213 ---help---
214 POSIX variant of message queues is a part of IPC. In POSIX message
215 queues every message has a priority which decides about succession
216 of receiving it by a process. If you want to compile and run
217 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200218 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
220 POSIX message queues are visible as a filesystem called 'mqueue'
221 and can be mounted somewhere if you want to do filesystem
222 operations on message queues.
223
224 If unsure, say Y.
225
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700226config POSIX_MQUEUE_SYSCTL
227 bool
228 depends on POSIX_MQUEUE
229 depends on SYSCTL
230 default y
231
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232config BSD_PROCESS_ACCT
233 bool "BSD Process Accounting"
234 help
235 If you say Y here, a user level program will be able to instruct the
236 kernel (via a special system call) to write process accounting
237 information to a file: whenever a process exits, information about
238 that process will be appended to the file by the kernel. The
239 information includes things such as creation time, owning user,
240 command name, memory usage, controlling terminal etc. (the complete
241 list is in the struct acct in <file:include/linux/acct.h>). It is
242 up to the user level program to do useful things with this
243 information. This is generally a good idea, so say Y.
244
245config BSD_PROCESS_ACCT_V3
246 bool "BSD Process Accounting version 3 file format"
247 depends on BSD_PROCESS_ACCT
248 default n
249 help
250 If you say Y here, the process accounting information is written
251 in a new file format that also logs the process IDs of each
252 process and it's parent. Note that this file format is incompatible
253 with previous v0/v1/v2 file formats, so you will need updated tools
254 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300255 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Shailabh Nagarc7572492006-07-14 00:24:40 -0700257config TASKSTATS
258 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
259 depends on NET
260 default n
261 help
262 Export selected statistics for tasks/processes through the
263 generic netlink interface. Unlike BSD process accounting, the
264 statistics are available during the lifetime of tasks/processes as
265 responses to commands. Like BSD accounting, they are sent to user
266 space on task exit.
267
268 Say N if unsure.
269
Shailabh Nagarca74e922006-07-14 00:24:36 -0700270config TASK_DELAY_ACCT
271 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700272 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700273 help
274 Collect information on time spent by a task waiting for system
275 resources like cpu, synchronous block I/O completion and swapping
276 in pages. Such statistics can help in setting a task's priorities
277 relative to other tasks for cpu, io, rss limits etc.
278
279 Say N if unsure.
280
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800281config TASK_XACCT
282 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
283 depends on TASKSTATS
284 help
285 Collect extended task accounting data and send the data
286 to userland for processing over the taskstats interface.
287
288 Say N if unsure.
289
290config TASK_IO_ACCOUNTING
291 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
292 depends on TASK_XACCT
293 help
294 Collect information on the number of bytes of storage I/O which this
295 task has caused.
296
297 Say N if unsure.
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299config AUDIT
300 bool "Auditing support"
Chris Wright804a6a42005-05-11 10:52:45 +0100301 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 help
303 Enable auditing infrastructure that can be used with another
304 kernel subsystem, such as SELinux (which requires this for
305 logging of avc messages output). Does not do system-call
306 auditing without CONFIG_AUDITSYSCALL.
307
308config AUDITSYSCALL
309 bool "Enable system-call auditing support"
Kumar Gala022382a2009-10-16 07:21:37 +0000310 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 default y if SECURITY_SELINUX
312 help
313 Enable low-overhead system-call auditing infrastructure that
314 can be used independently or with another kernel subsystem,
Amy Griffisf368c07d2006-04-07 16:55:56 -0400315 such as SELinux. To use audit's filesystem watch feature, please
316 ensure that INOTIFY is configured.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
Al Viro74c3cbe2007-07-22 08:04:18 -0400318config AUDIT_TREE
319 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400320 depends on AUDITSYSCALL
321 select INOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400322
Mike Travisc903ff82009-01-15 12:28:29 -0800323menu "RCU Subsystem"
324
325choice
326 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700327 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800328
Mike Travisc903ff82009-01-15 12:28:29 -0800329config TREE_RCU
330 bool "Tree-based hierarchical RCU"
331 help
332 This option selects the RCU implementation that is
333 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700334 thousands of CPUs. It also scales down nicely to
335 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800336
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700337config TREE_PREEMPT_RCU
338 bool "Preemptable tree-based hierarchical RCU"
339 depends on PREEMPT
340 help
341 This option selects the RCU implementation that is
342 designed for very large SMP systems with hundreds or
343 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700344 is also required. It also scales down nicely to
345 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700346
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700347config TINY_RCU
348 bool "UP-only small-memory-footprint RCU"
349 depends on !SMP
350 help
351 This option selects the RCU implementation that is
352 designed for UP systems from which real-time response
353 is not required. This option greatly reduces the
354 memory footprint of RCU.
355
Mike Travisc903ff82009-01-15 12:28:29 -0800356endchoice
357
358config RCU_TRACE
359 bool "Enable tracing for RCU"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700360 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800361 help
362 This option provides tracing in RCU which presents stats
363 in debugfs for debugging RCU implementation.
364
365 Say Y here if you want to enable RCU tracing
366 Say N if you are unsure.
367
368config RCU_FANOUT
369 int "Tree-based hierarchical RCU fanout value"
370 range 2 64 if 64BIT
371 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700372 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800373 default 64 if 64BIT
374 default 32 if !64BIT
375 help
376 This option controls the fanout of hierarchical implementations
377 of RCU, allowing RCU to work efficiently on machines with
378 large numbers of CPUs. This value must be at least the cube
379 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
380 systems and up to 262,144 for 64-bit systems.
381
382 Select a specific number if testing RCU itself.
383 Take the default if unsure.
384
385config RCU_FANOUT_EXACT
386 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700387 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800388 default n
389 help
390 This option forces use of the exact RCU_FANOUT value specified,
391 regardless of imbalances in the hierarchy. This is useful for
392 testing RCU itself, and might one day be useful on systems with
393 strong NUMA behavior.
394
395 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
396
397 Say N if unsure.
398
399config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700400 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800401 select DEBUG_FS
402 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700403 This option provides tracing for the TREE_RCU and
404 TREE_PREEMPT_RCU implementations, permitting Makefile to
405 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800406
Mike Travisc903ff82009-01-15 12:28:29 -0800407endmenu # "RCU Subsystem"
408
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700410 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 ---help---
412 This option enables the complete Linux kernel ".config" file
413 contents to be saved in the kernel. It provides documentation
414 of which kernel options are used in a running kernel or in an
415 on-disk kernel. This information can be extracted from the kernel
416 image file with the script scripts/extract-ikconfig and used as
417 input to rebuild the current kernel or to build another kernel.
418 It can also be extracted from a running kernel by reading
419 /proc/config.gz if enabled (below).
420
421config IKCONFIG_PROC
422 bool "Enable access to .config through /proc/config.gz"
423 depends on IKCONFIG && PROC_FS
424 ---help---
425 This option enables access to the kernel configuration file
426 through /proc/config.gz.
427
Alistair John Strachan794543a2007-05-08 00:31:15 -0700428config LOG_BUF_SHIFT
429 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
430 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700431 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700432 help
433 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700434 Examples:
435 17 => 128 KB
436 16 => 64 KB
437 15 => 32 KB
438 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700439 13 => 8 KB
440 12 => 4 KB
441
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800442#
443# Architectures with an unreliable sched_clock() should select this:
444#
445config HAVE_UNSTABLE_SCHED_CLOCK
446 bool
447
448config GROUP_SCHED
449 bool "Group CPU scheduler"
450 depends on EXPERIMENTAL
451 default n
452 help
453 This feature lets CPU scheduler recognize task groups and control CPU
454 bandwidth allocation to such task groups.
455 In order to create a group from arbitrary set of processes, use
456 CONFIG_CGROUPS. (See Control Group support.)
457
458config FAIR_GROUP_SCHED
459 bool "Group scheduling for SCHED_OTHER"
460 depends on GROUP_SCHED
461 default GROUP_SCHED
462
463config RT_GROUP_SCHED
464 bool "Group scheduling for SCHED_RR/FIFO"
465 depends on EXPERIMENTAL
466 depends on GROUP_SCHED
467 default n
468 help
469 This feature lets you explicitly allocate real CPU bandwidth
470 to users or control groups (depending on the "Basis for grouping tasks"
471 setting below. If enabled, it will also make it impossible to
472 schedule realtime tasks for non-root users until you allocate
473 realtime bandwidth for them.
474 See Documentation/scheduler/sched-rt-group.txt for more information.
475
476choice
477 depends on GROUP_SCHED
478 prompt "Basis for grouping tasks"
479 default USER_SCHED
480
481config USER_SCHED
482 bool "user id"
483 help
484 This option will choose userid as the basis for grouping
485 tasks, thus providing equal CPU bandwidth to each user.
486
487config CGROUP_SCHED
488 bool "Control groups"
489 depends on CGROUPS
490 help
491 This option allows you to create arbitrary task groups
492 using the "cgroup" pseudo filesystem and control
493 the cpu bandwidth allocated to each such task group.
Li Zefan45ce80f2009-01-15 13:50:59 -0800494 Refer to Documentation/cgroups/cgroups.txt for more
495 information on "cgroup" pseudo filesystem.
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800496
497endchoice
498
Li Zefan23964d22009-01-15 13:50:58 -0800499menuconfig CGROUPS
500 boolean "Control Group support"
Paul Menageddbcc7e2007-10-18 23:39:30 -0700501 help
Li Zefan23964d22009-01-15 13:50:58 -0800502 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800503 use with process control subsystems such as Cpusets, CFS, memory
504 controls or device isolation.
505 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800506 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800507 - Documentation/cgroups/ (features for grouping, isolation
508 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700509
510 Say N if unsure.
511
Li Zefan23964d22009-01-15 13:50:58 -0800512if CGROUPS
513
Paul Menage006cb992007-10-18 23:39:43 -0700514config CGROUP_DEBUG
515 bool "Example debug cgroup subsystem"
516 depends on CGROUPS
Paul Menage418d7d82008-04-29 01:00:05 -0700517 default n
Paul Menage006cb992007-10-18 23:39:43 -0700518 help
519 This option enables a simple cgroup subsystem that
520 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800521 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700522
Li Zefan23964d22009-01-15 13:50:58 -0800523 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700524
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700525config CGROUP_NS
Li Zefan23964d22009-01-15 13:50:58 -0800526 bool "Namespace cgroup subsystem"
527 depends on CGROUPS
528 help
529 Provides a simple namespace cgroup subsystem to
530 provide hierarchical naming of sets of namespaces,
531 for instance virtual servers and checkpoint/restart
532 jobs.
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700533
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700534config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800535 bool "Freezer cgroup subsystem"
536 depends on CGROUPS
537 help
538 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700539 cgroup.
540
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700541config CGROUP_DEVICE
542 bool "Device controller for cgroups"
543 depends on CGROUPS && EXPERIMENTAL
544 help
545 Provides a cgroup implementing whitelists for devices which
546 a process in the cgroup can mknod or open.
547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548config CPUSETS
549 bool "Cpuset support"
Paul Menagedb7f47c2009-04-02 16:57:55 -0700550 depends on CGROUPS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700552 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 allow dynamically partitioning a system into sets of CPUs and
554 Memory Nodes and assigning tasks to run only within those sets.
555 This is primarily useful on large SMP or NUMA systems.
556
557 Say N if unsure.
558
Li Zefan23964d22009-01-15 13:50:58 -0800559config PROC_PID_CPUSET
560 bool "Include legacy /proc/<pid>/cpuset file"
561 depends on CPUSETS
562 default y
563
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100564config CGROUP_CPUACCT
565 bool "Simple CPU accounting cgroup subsystem"
566 depends on CGROUPS
567 help
568 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800569 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100570
Pavel Emelianove552b662008-02-07 00:13:49 -0800571config RESOURCE_COUNTERS
572 bool "Resource counters"
573 help
574 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800575 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800576 depends on CGROUPS
577
Balbir Singh00f0b822008-03-04 14:28:39 -0800578config CGROUP_MEM_RES_CTLR
579 bool "Memory Resource Controller for Control Groups"
580 depends on CGROUPS && RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700581 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800582 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700583 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100584 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800585
586 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700587 associated with each page of memory in the system. By this,
588 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
589 usage tracking struct at boot. Total amount of this is printed out
590 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800591
592 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700593 sure you need the memory resource controller. Even when you enable
594 this, you can set "cgroup_disable=memory" at your boot option to
595 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800596 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800597
Balbir Singhcf475ad2008-04-29 01:00:16 -0700598 This config option also selects MM_OWNER config option, which
599 could in turn add some fork/exit overhead.
600
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800601config CGROUP_MEM_RES_CTLR_SWAP
602 bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)"
603 depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL
604 help
605 Add swap management feature to memory resource controller. When you
606 enable this, you can limit mem+swap usage per cgroup. In other words,
607 when you disable this, memory resource controller has no cares to
608 usage of swap...a process can exhaust all of the swap. This extension
609 is useful when you want to avoid exhaustion swap but this itself
610 adds more overheads and consumes memory for remembering information.
611 Especially if you use 32bit system or small memory system, please
612 be careful about enabling this. When memory resource controller
613 is disabled by boot option, this will be automatically disabled and
614 there will be no overhead from this. Even when you set this config=y,
615 if boot option "noswapaccount" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700616 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
617 size is 4096bytes, 512k per 1Gbytes of swap.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800618
Li Zefan23964d22009-01-15 13:50:58 -0800619endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800620
Li Zefan23964d22009-01-15 13:50:58 -0800621config MM_OWNER
622 bool
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800623
Kay Sievers88a22c92006-09-14 11:23:28 +0200624config SYSFS_DEPRECATED
Ingo Molnard47846c2008-03-04 14:54:47 +0100625 bool
626
627config SYSFS_DEPRECATED_V2
Uwe Kleine-König9e9868a2009-12-03 19:58:00 +0100628 bool "enable deprecated sysfs features to support old userspace tools"
Randy Dunlap9148fe82007-12-31 10:05:34 -0800629 depends on SYSFS
Kay Sieversf6ee6492009-04-16 19:56:37 +0200630 default n
Ingo Molnard47846c2008-03-04 14:54:47 +0100631 select SYSFS_DEPRECATED
Kay Sievers88a22c92006-09-14 11:23:28 +0200632 help
Kay Sieversfce3e802008-11-01 14:03:00 +0100633 This option switches the layout of sysfs to the deprecated
Kay Sieversf6ee6492009-04-16 19:56:37 +0200634 version. Do not use it on recent distributions.
Kay Sievers88a22c92006-09-14 11:23:28 +0200635
Kay Sieversfce3e802008-11-01 14:03:00 +0100636 The current sysfs layout features a unified device tree at
637 /sys/devices/, which is able to express a hierarchy between
638 class devices. If the deprecated option is set to Y, the
639 unified device tree is split into a bus device tree at
640 /sys/devices/ and several individual class device trees at
641 /sys/class/. The class and bus devices will be connected by
642 "<subsystem>:<name>" and the "device" links. The "block"
643 class devices, will not show up in /sys/class/block/. Some
644 subsystems will suppress the creation of some devices which
645 depend on the unified device tree.
Kay Sievers88a22c92006-09-14 11:23:28 +0200646
Kay Sieversfce3e802008-11-01 14:03:00 +0100647 This option is not a pure compatibility option that can
648 be safely enabled on newer distributions. It will change the
649 layout of sysfs to the non-extensible deprecated version,
650 and disable some features, which can not be exported without
651 confusing older userspace tools. Since 2007/2008 all major
652 distributions do not enable this option, and ship no tools which
653 depend on the deprecated layout or this option.
654
655 If you are using a new kernel on an older distribution, or use
656 older userspace tools, you might need to say Y here. Do not say Y,
657 if the original kernel, that came with your distribution, has
658 this option set to N.
Kay Sievers88a22c92006-09-14 11:23:28 +0200659
Jens Axboeb86ff982006-03-23 19:56:55 +0100660config RELAY
661 bool "Kernel->user space relay support (formerly relayfs)"
662 help
663 This option enables support for relay interface support in
664 certain file systems (such as debugfs).
665 It is designed to provide an efficient mechanism for tools and
666 facilities to relay large amounts of data from kernel space to
667 user space.
668
669 If unsure, say N.
670
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800671config NAMESPACES
672 bool "Namespaces support" if EMBEDDED
673 default !EMBEDDED
674 help
675 Provides the way to make tasks work with different objects using
676 the same id. For example same IPC id may refer to different objects
677 or same user id or pid may refer to different tasks when used in
678 different namespaces.
679
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800680config UTS_NS
681 bool "UTS namespace"
682 depends on NAMESPACES
683 help
684 In this namespace tasks see different info provided with the
685 uname() system call
686
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800687config IPC_NS
688 bool "IPC namespace"
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700689 depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800690 help
691 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700692 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800693
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800694config USER_NS
695 bool "User namespace (EXPERIMENTAL)"
696 depends on NAMESPACES && EXPERIMENTAL
697 help
698 This allows containers, i.e. vservers, to use user namespaces
699 to provide different user info for different servers.
700 If unsure, say N.
701
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800702config PID_NS
703 bool "PID Namespaces (EXPERIMENTAL)"
704 default n
705 depends on NAMESPACES && EXPERIMENTAL
706 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300707 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100708 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800709 pid namespaces. This is a building block of containers.
710
711 Unless you want to work with an experimental feature
712 say N here.
713
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800714config NET_NS
715 bool "Network namespace"
716 default n
717 depends on NAMESPACES && EXPERIMENTAL && NET
718 help
719 Allow user space to create what appear to be multiple instances
720 of the network stack.
721
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800722config BLK_DEV_INITRD
723 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
724 depends on BROKEN || !FRV
725 help
726 The initial RAM filesystem is a ramfs which is loaded by the
727 boot loader (loadlin or lilo) and that is mounted as root
728 before the normal boot procedure. It is typically used to
729 load modules needed to mount the "real" root file system,
730 etc. See <file:Documentation/initrd.txt> for details.
731
732 If RAM disk support (BLK_DEV_RAM) is also included, this
733 also enables initial RAM disk (initrd) support and adds
734 15 Kbytes (more on some other architectures) to the kernel size.
735
736 If unsure say Y.
737
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800738if BLK_DEV_INITRD
739
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200740source "usr/Kconfig"
741
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800742endif
743
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800744config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200745 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800746 default y
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800747 help
748 Enabling this option will pass "-Os" instead of "-O2" to gcc
749 resulting in a smaller kernel.
750
jkacur775a7222008-07-16 00:31:16 +0200751 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800752
Randy Dunlap08470622006-09-30 23:28:13 -0700753config SYSCTL
754 bool
755
Randy Dunlapb943c462009-03-10 12:55:46 -0700756config ANON_INODES
757 bool
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759menuconfig EMBEDDED
760 bool "Configure standard kernel features (for small systems)"
761 help
762 This option allows certain base kernel options and settings
763 to be disabled or tweaked. This is for specialized
764 environments which can tolerate a "non-standard" kernel.
765 Only use this if you really know what you are doing.
766
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700767config UID16
768 bool "Enable 16-bit UID system calls" if EMBEDDED
David S. Miller09337f52008-04-26 03:17:12 -0700769 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700770 default y
771 help
772 This enables the legacy 16-bit UID syscall wrappers.
773
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700774config SYSCTL_SYSCALL
Randy Dunlap08470622006-09-30 23:28:13 -0700775 bool "Sysctl syscall support" if EMBEDDED
Eric W. Biederman26a70342009-11-05 05:26:41 -0800776 depends on PROC_SYSCTL
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800777 default y
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700778 select SYSCTL
779 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800780 sys_sysctl uses binary paths that have been found challenging
781 to properly maintain and use. The interface in /proc/sys
782 using paths with ascii names is now the primary path to this
783 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700784
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800785 Almost nothing using the binary sysctl interface so if you are
786 trying to save some space it is probably safe to disable this,
787 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700788
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800789 If unsure say Y here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700790
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791config KALLSYMS
Jesper Juhl979c6a12006-12-12 19:25:11 +0100792 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 default y
794 help
795 Say Y here to let the kernel print out symbolic crash information and
796 symbolic stack backtraces. This increases the size of the kernel
797 somewhat, as all symbols have to be loaded into the kernel image.
798
799config KALLSYMS_ALL
800 bool "Include all symbols in kallsyms"
801 depends on DEBUG_KERNEL && KALLSYMS
802 help
803 Normally kallsyms only contains the symbols of functions, for nicer
804 OOPS messages. Some debuggers can use kallsyms for other
Jesper Juhlf9f97bc2005-07-20 05:43:05 +0200805 symbols too: say Y here to include all symbols, if you need them
806 and you don't care about adding 300k to the size of your kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807
808 Say N.
809
810config KALLSYMS_EXTRA_PASS
811 bool "Do an extra kallsyms pass"
812 depends on KALLSYMS
813 help
814 If kallsyms is not working correctly, the build will fail with
815 inconsistent kallsyms data. If that occurs, log a bug report and
816 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
817 Always say N here unless you find a bug in kallsyms, which must be
818 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
819 you wait for kallsyms to be fixed.
820
Matt Mackalld59745c2005-05-01 08:59:02 -0700821
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -0800822config HOTPLUG
823 bool "Support for hot-pluggable devices" if EMBEDDED
824 default y
825 help
826 This option is provided for the case where no hotplug or uevent
827 capabilities is wanted by the kernel. You should only consider
828 disabling this option for embedded systems that do not use modules, a
829 dynamic /dev tree, or dynamic device discovery. Just say Y.
830
Matt Mackalld59745c2005-05-01 08:59:02 -0700831config PRINTK
832 default y
833 bool "Enable support for printk" if EMBEDDED
834 help
835 This option enables normal printk support. Removing it
836 eliminates most of the message strings from the kernel image
837 and makes the kernel more or less silent. As this makes it
838 very difficult to diagnose system problems, saying N here is
839 strongly discouraged.
840
Matt Mackallc8538a72005-05-01 08:59:01 -0700841config BUG
842 bool "BUG() support" if EMBEDDED
843 default y
844 help
845 Disabling this option eliminates support for BUG and WARN, reducing
846 the size of your kernel image and potentially quietly ignoring
847 numerous fatal conditions. You should only consider disabling this
848 option for embedded systems with no facilities for reporting errors.
849 Just say Y.
850
Matt Mackall708e9a72006-01-08 01:05:25 -0800851config ELF_CORE
852 default y
853 bool "Enable ELF core dumps" if EMBEDDED
854 help
855 Enable support for generating core dumps. Disabling saves about 4k.
856
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +0200857config PCSPKR_PLATFORM
858 bool "Enable PC-Speaker support" if EMBEDDED
859 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
860 default y
861 help
862 This option allows to disable the internal PC-Speaker
863 support, saving some memory.
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865config BASE_FULL
866 default y
867 bool "Enable full-sized data structures for core" if EMBEDDED
868 help
869 Disabling this option reduces the size of miscellaneous core
870 kernel data structures. This saves memory on small machines,
871 but may reduce performance.
872
873config FUTEX
874 bool "Enable futex support" if EMBEDDED
875 default y
Ingo Molnar23f78d42006-06-27 02:54:53 -0700876 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 help
878 Disabling this option will cause the kernel to be built without
879 support for "fast userspace mutexes". The resulting kernel may not
880 run glibc-based applications correctly.
881
882config EPOLL
883 bool "Enable eventpoll support" if EMBEDDED
884 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700885 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 help
887 Disabling this option will cause the kernel to be built without
888 support for epoll family of system calls.
889
Davide Libenzifba2afa2007-05-10 22:23:13 -0700890config SIGNALFD
891 bool "Enable signalfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700892 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -0700893 default y
894 help
895 Enable the signalfd() system call that allows to receive signals
896 on a file descriptor.
897
898 If unsure, say Y.
899
Davide Libenzib215e282007-05-10 22:23:16 -0700900config TIMERFD
901 bool "Enable timerfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700902 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -0700903 default y
904 help
905 Enable the timerfd() system call that allows to receive timer
906 events on a file descriptor.
907
908 If unsure, say Y.
909
Davide Libenzie1ad7462007-05-10 22:23:19 -0700910config EVENTFD
911 bool "Enable eventfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700912 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -0700913 default y
914 help
915 Enable the eventfd() system call that allows to receive both
916 kernel notification (ie. KAIO) or userspace notifications.
917
918 If unsure, say Y.
919
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920config SHMEM
921 bool "Use full shmem filesystem" if EMBEDDED
922 default y
923 depends on MMU
924 help
925 The shmem is an internal filesystem used to manage shared memory.
926 It is backed by swap and manages resource limits. It is also exported
927 to userspace as tmpfs if TMPFS is enabled. Disabling this
928 option replaces shmem and tmpfs with the much simpler ramfs code,
929 which may be appropriate on small systems without swap.
930
Thomas Petazzoniebf3f092008-10-15 22:05:12 -0700931config AIO
932 bool "Enable AIO support" if EMBEDDED
933 default y
934 help
935 This option enables POSIX asynchronous I/O which may by used
936 by some high performance threaded applications. Disabling
937 this option saves about 7k.
938
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200939config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +0100940 bool
Mike Frysinger018df722009-06-12 13:17:43 -0400941 help
942 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100943
Peter Zijlstra906010b2009-09-21 16:08:49 +0200944config PERF_USE_VMALLOC
945 bool
946 help
947 See tools/perf/design.txt for details
948
Ingo Molnar57c0c152009-09-21 12:20:38 +0200949menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +0100950
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200951config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +0200952 bool "Kernel performance events and counters"
953 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200954 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +0100955 select ANON_INODES
Thomas Gleixner0793a612008-12-04 20:12:29 +0100956 help
Ingo Molnar57c0c152009-09-21 12:20:38 +0200957 Enable kernel support for various performance events provided
958 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100959
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -0200960 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +0200961 use of generic tracepoints.
962
963 Most modern CPUs support performance events via performance
964 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +0100965 types of hw events: such as instructions executed, cachemisses
966 suffered, or branches mis-predicted - without slowing down the
967 kernel or applications. These registers can also trigger interrupts
968 when a threshold number of events have passed - and can thus be
969 used to profile the code that runs on that CPU.
970
Ingo Molnar57c0c152009-09-21 12:20:38 +0200971 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -0200972 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +0200973 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +0100974 provides per task and per CPU counters, and it provides event
975 capabilities on top of those.
976
977 Say Y if unsure.
978
Peter Zijlstrae077df42009-03-19 20:26:17 +0100979config EVENT_PROFILE
Peter Zijlstra470a1392009-07-29 10:50:09 +0200980 bool "Tracepoint profiling sources"
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200981 depends on PERF_EVENTS && EVENT_TRACING
Peter Zijlstrae077df42009-03-19 20:26:17 +0100982 default y
Peter Zijlstra470a1392009-07-29 10:50:09 +0200983 help
Ingo Molnar57c0c152009-09-21 12:20:38 +0200984 Allow the use of tracepoints as software performance events.
Peter Zijlstra470a1392009-07-29 10:50:09 +0200985
Ingo Molnar57c0c152009-09-21 12:20:38 +0200986 When this is enabled, you can create perf events based on
Peter Zijlstra470a1392009-07-29 10:50:09 +0200987 tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID
988 found in debugfs://tracing/events/*/*/id. (The -e/--events
989 option to the perf tool can parse and interpret symbolic
990 tracepoints, in the subsystem:tracepoint_name format.)
Peter Zijlstrae077df42009-03-19 20:26:17 +0100991
Ingo Molnar57c0c152009-09-21 12:20:38 +0200992config PERF_COUNTERS
993 bool "Kernel performance counters (old config option)"
994 depends on HAVE_PERF_EVENTS
995 help
996 This config has been obsoleted by the PERF_EVENTS
997 config option - please see that one for details.
998
999 It has no effect on the kernel whether you enable
1000 it or not, it is a compatibility placeholder.
1001
1002 Say N if unsure.
1003
Peter Zijlstra906010b2009-09-21 16:08:49 +02001004config DEBUG_PERF_USE_VMALLOC
1005 default n
1006 bool "Debug: use vmalloc to back perf mmap() buffers"
1007 depends on PERF_EVENTS && DEBUG_KERNEL
1008 select PERF_USE_VMALLOC
1009 help
1010 Use vmalloc memory to back perf mmap() buffers.
1011
1012 Mostly useful for debugging the vmalloc code on platforms
1013 that don't require it.
1014
1015 Say N if unsure.
1016
Thomas Gleixner0793a612008-12-04 20:12:29 +01001017endmenu
1018
Christoph Lameterf8891e52006-06-30 01:55:45 -07001019config VM_EVENT_COUNTERS
1020 default y
1021 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1022 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001023 VM event counters are needed for event counts to be shown.
1024 This option allows the disabling of the VM event counters
1025 on EMBEDDED systems. /proc/vmstat will only show page counts
1026 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001027
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001028config PCI_QUIRKS
1029 default y
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001030 bool "Enable PCI quirk workarounds" if EMBEDDED
1031 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001032 help
1033 This enables workarounds for various PCI chipset
1034 bugs/quirks. Disable this only if your target machine is
1035 unaffected by PCI quirks.
1036
Christoph Lameter41ecc552007-05-09 02:32:44 -07001037config SLUB_DEBUG
1038 default y
1039 bool "Enable SLUB debugging support" if EMBEDDED
Christoph Lameterf6acb632008-04-29 16:16:06 -07001040 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001041 help
1042 SLUB has extensive debug support features. Disabling these can
1043 result in significant savings in code size. This also disables
1044 SLUB sysfs support. /sys/slab will not exist and there will be
1045 no support for cache validation etc.
1046
Randy Dunlapb943c462009-03-10 12:55:46 -07001047config COMPAT_BRK
1048 bool "Disable heap randomization"
1049 default y
1050 help
1051 Randomizing heap placement makes heap exploits harder, but it
1052 also breaks ancient binaries (including anything libc5 based).
1053 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001054 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001055 /proc/sys/kernel/randomize_va_space to 2.
1056
1057 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1058
Christoph Lameter81819f02007-05-06 14:49:36 -07001059choice
1060 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001061 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001062 help
1063 This option allows to select a slab allocator.
1064
1065config SLAB
1066 bool "SLAB"
1067 help
1068 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001069 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001070 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001071
1072config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001073 bool "SLUB (Unqueued Allocator)"
1074 help
1075 SLUB is a slab allocator that minimizes cache line usage
1076 instead of managing queues of cached objects (SLAB approach).
1077 Per cpu caching is realized using slabs of objects instead
1078 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001079 and has enhanced diagnostics. SLUB is the default choice for
1080 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001081
1082config SLOB
Paul Mundt84a01c22007-07-15 23:38:24 -07001083 depends on EMBEDDED
Christoph Lameter81819f02007-05-06 14:49:36 -07001084 bool "SLOB (Simple Allocator)"
1085 help
Matt Mackall37291452008-02-04 22:29:38 -08001086 SLOB replaces the stock allocator with a drastically simpler
1087 allocator. SLOB is generally more space efficient but
1088 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001089
1090endchoice
1091
Jie Zhangea637632009-12-14 18:00:02 -08001092config MMAP_ALLOW_UNINITIALIZED
1093 bool "Allow mmapped anonymous memory to be uninitialized"
1094 depends on EMBEDDED && !MMU
1095 default n
1096 help
1097 Normally, and according to the Linux spec, anonymous memory obtained
1098 from mmap() has it's contents cleared before it is passed to
1099 userspace. Enabling this config option allows you to request that
1100 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1101 providing a huge performance boost. If this option is not enabled,
1102 then the flag will be ignored.
1103
1104 This is taken advantage of by uClibc's malloc(), and also by
1105 ELF-FDPIC binfmt's brk and stack allocator.
1106
1107 Because of the obvious security issues, this option should only be
1108 enabled on embedded devices where you control what is run in
1109 userspace. Since that isn't generally a problem on no-MMU systems,
1110 it is normally safe to say Y here.
1111
1112 See Documentation/nommu-mmap.txt for more information.
1113
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001114config PROFILING
1115 bool "Profiling support (EXPERIMENTAL)"
1116 help
1117 Say Y here to enable the extended profiling support mechanisms used
1118 by profilers such as OProfile.
1119
Ingo Molnar5f87f112008-07-23 14:15:22 +02001120#
1121# Place an empty function call at each tracepoint site. Can be
1122# dynamically changed for a probe function.
1123#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001124config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001125 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001126
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001127source "arch/Kconfig"
1128
David Howells07fe7cb2009-04-03 16:42:35 +01001129config SLOW_WORK
1130 default n
David Howells1c2d0082009-04-06 15:47:25 +01001131 bool
David Howells07fe7cb2009-04-03 16:42:35 +01001132 help
1133 The slow work thread pool provides a number of dynamically allocated
1134 threads that can be used by the kernel to perform operations that
1135 take a relatively long time.
1136
1137 An example of this would be CacheFiles doing a path lookup followed
1138 by a series of mkdirs and a create call, all of which have to touch
1139 disk.
1140
David Howells1c2d0082009-04-06 15:47:25 +01001141 See Documentation/slow-work.txt.
1142
David Howellsf13a48b2009-12-01 15:36:11 +00001143config SLOW_WORK_DEBUG
1144 bool "Slow work debugging through debugfs"
David Howells8fba10a2009-11-19 18:10:51 +00001145 default n
David Howellsf13a48b2009-12-01 15:36:11 +00001146 depends on SLOW_WORK && DEBUG_FS
David Howells8fba10a2009-11-19 18:10:51 +00001147 help
David Howellsf13a48b2009-12-01 15:36:11 +00001148 Display the contents of the slow work run queue through debugfs,
David Howells8fba10a2009-11-19 18:10:51 +00001149 including items currently executing.
1150
1151 See Documentation/slow-work.txt.
1152
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153endmenu # General setup
1154
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001155config HAVE_GENERIC_DMA_COHERENT
1156 bool
1157 default n
1158
Linus Torvalds158a9622008-01-02 13:04:48 -08001159config SLABINFO
1160 bool
1161 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001162 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001163 default y
1164
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001165config RT_MUTEXES
1166 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001167
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168config BASE_SMALL
1169 int
1170 default 0 if BASE_FULL
1171 default 1 if !BASE_FULL
1172
Jan Engelhardt66da5732007-07-15 23:39:29 -07001173menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 bool "Enable loadable module support"
1175 help
1176 Kernel modules are small pieces of compiled code which can
1177 be inserted in the running kernel, rather than being
1178 permanently built into the kernel. You use the "modprobe"
1179 tool to add (and sometimes remove) them. If you say Y here,
1180 many parts of the kernel can be built as modules (by
1181 answering M instead of Y where indicated): this is most
1182 useful for infrequently used options which are not required
1183 for booting. For more information, see the man pages for
1184 modprobe, lsmod, modinfo, insmod and rmmod.
1185
1186 If you say Y here, you will need to run "make
1187 modules_install" to put the modules under /lib/modules/
1188 where modprobe can find them (you may need to be root to do
1189 this).
1190
1191 If unsure, say Y.
1192
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001193if MODULES
1194
Linus Torvalds826e4502008-05-04 17:04:16 -07001195config MODULE_FORCE_LOAD
1196 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001197 default n
1198 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001199 Allow loading of modules without version information (ie. modprobe
1200 --force). Forced module loading sets the 'F' (forced) taint flag and
1201 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001202
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203config MODULE_UNLOAD
1204 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 help
1206 Without this option you will not be able to unload any
1207 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001208 anyway), which makes your kernel smaller, faster
1209 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210
1211config MODULE_FORCE_UNLOAD
1212 bool "Forced module unloading"
1213 depends on MODULE_UNLOAD && EXPERIMENTAL
1214 help
1215 This option allows you to force a module to unload, even if the
1216 kernel believes it is unsafe: the kernel will remove the module
1217 without waiting for anyone to stop using it (using the -f option to
1218 rmmod). This is mainly for kernel developers and desperate users.
1219 If unsure, say N.
1220
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001222 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223 help
1224 Usually, you have to use modules compiled with your kernel.
1225 Saying Y here makes it sometimes possible to use modules
1226 compiled for different kernels, by adding enough information
1227 to the modules to (hopefully) spot any changes which would
1228 make them incompatible with the kernel you are running. If
1229 unsure, say N.
1230
1231config MODULE_SRCVERSION_ALL
1232 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 help
1234 Modules which contain a MODULE_VERSION get an extra "srcversion"
1235 field inserted into their modinfo section, which contains a
1236 sum of the source files which made it. This helps maintainers
1237 see exactly which source was used to build a module (since
1238 others sometimes change the module source without updating
1239 the version). With this option, such a "srcversion" field
1240 will be created for all modules. If unsure, say N.
1241
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001242endif # MODULES
1243
Rusty Russell98a79d62008-12-13 21:19:41 +10301244config INIT_ALL_POSSIBLE
1245 bool
1246 help
1247 Back when each arch used to define their own cpu_online_map and
1248 cpu_possible_map, some of them chose to initialize cpu_possible_map
1249 with all 1s, and others with all 0s. When they were centralised,
1250 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001251 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301252
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253config STOP_MACHINE
1254 bool
1255 default y
1256 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1257 help
1258 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001259
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001260source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001261
1262config PREEMPT_NOTIFIERS
1263 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001264
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001265source "kernel/Kconfig.locks"