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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47 drivers that have been replaced by something else, and/or are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
Roland McGrath84336462009-12-21 16:24:06 -080079config CROSS_COMPILE
80 string "Cross-compiler tool prefix"
81 help
82 Same as running 'make CROSS_COMPILE=prefix-' but stored for
83 default make runs in this kernel build directory. You don't
84 need to set this unless you want the configured kernel build
85 directory to select the cross-compiler automatically.
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087config LOCALVERSION
88 string "Local version - append to kernel release"
89 help
90 Append an extra string to the end of your kernel version.
91 This will show up when you type uname, for example.
92 The string you set here will be appended after the contents of
93 any files with a filename matching localversion* in your
94 object and source tree, in that order. Your total string can
95 be a maximum of 64 characters.
96
Ryan Andersonaaebf432005-07-31 04:57:49 -040097config LOCALVERSION_AUTO
98 bool "Automatically append version information to the version string"
99 default y
100 help
101 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200102 release tree by looking for git tags that belong to the current
103 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400104
105 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200106 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400107 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200108 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400109
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200110 (The actual string used here is the first eight characters produced
111 by running the command:
112
113 $ git rev-parse --verify HEAD
114
115 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400116
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800117config HAVE_KERNEL_GZIP
118 bool
119
120config HAVE_KERNEL_BZIP2
121 bool
122
123config HAVE_KERNEL_LZMA
124 bool
125
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800126config HAVE_KERNEL_LZO
127 bool
128
Alain Knaff30d65db2009-01-04 22:46:17 +0100129choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800130 prompt "Kernel compression mode"
131 default KERNEL_GZIP
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800132 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800133 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100134 The linux kernel is a kind of self-extracting executable.
135 Several compression algorithms are available, which differ
136 in efficiency, compression and decompression speed.
137 Compression speed is only relevant when building a kernel.
138 Decompression speed is relevant at each boot.
139
140 If you have any problems with bzip2 or lzma compressed
141 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
142 version of this functionality (bzip2 only), for 2.4, was
143 supplied by Christian Ludwig)
144
145 High compression options are mostly useful for users, who
146 are low on disk space (embedded systems), but for whom ram
147 size matters less.
148
149 If in doubt, select 'gzip'
150
151config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800152 bool "Gzip"
153 depends on HAVE_KERNEL_GZIP
154 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800155 The old and tried gzip compression. It provides a good balance
156 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100157
158config KERNEL_BZIP2
159 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800160 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100161 help
162 Its compression ratio and speed is intermediate.
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800163 Decompression speed is slowest among the three. The kernel
164 size is about 10% smaller with bzip2, in comparison to gzip.
165 Bzip2 uses a large amount of memory. For modern kernels you
166 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100167
168config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800169 bool "LZMA"
170 depends on HAVE_KERNEL_LZMA
171 help
172 The most recent compression algorithm.
173 Its ratio is best, decompression speed is between the other
174 two. Compression is slowest. The kernel size is about 33%
175 smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100176
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800177config KERNEL_LZO
178 bool "LZO"
179 depends on HAVE_KERNEL_LZO
180 help
181 Its compression ratio is the poorest among the 4. The kernel
182 size is about about 10% bigger than gzip; however its speed
183 (both compression and decompression) is the fastest.
184
Alain Knaff30d65db2009-01-04 22:46:17 +0100185endchoice
186
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187config SWAP
188 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200189 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 default y
191 help
192 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100193 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 used to provide more virtual memory than the actual RAM present
195 in your computer. If unsure say Y.
196
197config SYSVIPC
198 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 ---help---
200 Inter Process Communication is a suite of library functions and
201 system calls which let processes (running programs) synchronize and
202 exchange information. It is generally considered to be a good thing,
203 and some programs won't run unless you say Y here. In particular, if
204 you want to run the DOS emulator dosemu under Linux (read the
205 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
206 you'll need to say Y here.
207
208 You can find documentation about IPC with "info ipc" and also in
209 section 6.4 of the Linux Programmer's Guide, available from
210 <http://www.tldp.org/guides.html>.
211
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800212config SYSVIPC_SYSCTL
213 bool
214 depends on SYSVIPC
215 depends on SYSCTL
216 default y
217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218config POSIX_MQUEUE
219 bool "POSIX Message Queues"
220 depends on NET && EXPERIMENTAL
221 ---help---
222 POSIX variant of message queues is a part of IPC. In POSIX message
223 queues every message has a priority which decides about succession
224 of receiving it by a process. If you want to compile and run
225 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200226 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228 POSIX message queues are visible as a filesystem called 'mqueue'
229 and can be mounted somewhere if you want to do filesystem
230 operations on message queues.
231
232 If unsure, say Y.
233
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700234config POSIX_MQUEUE_SYSCTL
235 bool
236 depends on POSIX_MQUEUE
237 depends on SYSCTL
238 default y
239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240config BSD_PROCESS_ACCT
241 bool "BSD Process Accounting"
242 help
243 If you say Y here, a user level program will be able to instruct the
244 kernel (via a special system call) to write process accounting
245 information to a file: whenever a process exits, information about
246 that process will be appended to the file by the kernel. The
247 information includes things such as creation time, owning user,
248 command name, memory usage, controlling terminal etc. (the complete
249 list is in the struct acct in <file:include/linux/acct.h>). It is
250 up to the user level program to do useful things with this
251 information. This is generally a good idea, so say Y.
252
253config BSD_PROCESS_ACCT_V3
254 bool "BSD Process Accounting version 3 file format"
255 depends on BSD_PROCESS_ACCT
256 default n
257 help
258 If you say Y here, the process accounting information is written
259 in a new file format that also logs the process IDs of each
260 process and it's parent. Note that this file format is incompatible
261 with previous v0/v1/v2 file formats, so you will need updated tools
262 for processing it. A preliminary version of these tools is available
S.Çağlar Onur37a4c942008-06-18 11:45:13 +0300263 at <http://www.gnu.org/software/acct/>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Shailabh Nagarc7572492006-07-14 00:24:40 -0700265config TASKSTATS
266 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
267 depends on NET
268 default n
269 help
270 Export selected statistics for tasks/processes through the
271 generic netlink interface. Unlike BSD process accounting, the
272 statistics are available during the lifetime of tasks/processes as
273 responses to commands. Like BSD accounting, they are sent to user
274 space on task exit.
275
276 Say N if unsure.
277
Shailabh Nagarca74e922006-07-14 00:24:36 -0700278config TASK_DELAY_ACCT
279 bool "Enable per-task delay accounting (EXPERIMENTAL)"
Shailabh Nagar6f449932006-07-14 00:24:41 -0700280 depends on TASKSTATS
Shailabh Nagarca74e922006-07-14 00:24:36 -0700281 help
282 Collect information on time spent by a task waiting for system
283 resources like cpu, synchronous block I/O completion and swapping
284 in pages. Such statistics can help in setting a task's priorities
285 relative to other tasks for cpu, io, rss limits etc.
286
287 Say N if unsure.
288
Alexey Dobriyan18f705f2007-02-10 01:46:44 -0800289config TASK_XACCT
290 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
291 depends on TASKSTATS
292 help
293 Collect extended task accounting data and send the data
294 to userland for processing over the taskstats interface.
295
296 Say N if unsure.
297
298config TASK_IO_ACCOUNTING
299 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
300 depends on TASK_XACCT
301 help
302 Collect information on the number of bytes of storage I/O which this
303 task has caused.
304
305 Say N if unsure.
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307config AUDIT
308 bool "Auditing support"
Chris Wright804a6a42005-05-11 10:52:45 +0100309 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 help
311 Enable auditing infrastructure that can be used with another
312 kernel subsystem, such as SELinux (which requires this for
313 logging of avc messages output). Does not do system-call
314 auditing without CONFIG_AUDITSYSCALL.
315
316config AUDITSYSCALL
317 bool "Enable system-call auditing support"
Kumar Gala022382a2009-10-16 07:21:37 +0000318 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 default y if SECURITY_SELINUX
320 help
321 Enable low-overhead system-call auditing infrastructure that
322 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500323 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Eric Paris939a67f2009-12-17 20:12:06 -0500325config AUDIT_WATCH
326 def_bool y
327 depends on AUDITSYSCALL
328 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
Al Viro74c3cbe2007-07-22 08:04:18 -0400330config AUDIT_TREE
331 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400332 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500333 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400334
Mike Travisc903ff82009-01-15 12:28:29 -0800335menu "RCU Subsystem"
336
337choice
338 prompt "RCU Implementation"
Paul E. McKenney31c9a242009-04-02 21:06:25 -0700339 default TREE_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800340
Mike Travisc903ff82009-01-15 12:28:29 -0800341config TREE_RCU
342 bool "Tree-based hierarchical RCU"
343 help
344 This option selects the RCU implementation that is
345 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700346 thousands of CPUs. It also scales down nicely to
347 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800348
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700349config TREE_PREEMPT_RCU
350 bool "Preemptable tree-based hierarchical RCU"
351 depends on PREEMPT
352 help
353 This option selects the RCU implementation that is
354 designed for very large SMP systems with hundreds or
355 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700356 is also required. It also scales down nicely to
357 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700358
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700359config TINY_RCU
360 bool "UP-only small-memory-footprint RCU"
361 depends on !SMP
362 help
363 This option selects the RCU implementation that is
364 designed for UP systems from which real-time response
365 is not required. This option greatly reduces the
366 memory footprint of RCU.
367
Mike Travisc903ff82009-01-15 12:28:29 -0800368endchoice
369
370config RCU_TRACE
371 bool "Enable tracing for RCU"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700372 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800373 help
374 This option provides tracing in RCU which presents stats
375 in debugfs for debugging RCU implementation.
376
377 Say Y here if you want to enable RCU tracing
378 Say N if you are unsure.
379
380config RCU_FANOUT
381 int "Tree-based hierarchical RCU fanout value"
382 range 2 64 if 64BIT
383 range 2 32 if !64BIT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700384 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800385 default 64 if 64BIT
386 default 32 if !64BIT
387 help
388 This option controls the fanout of hierarchical implementations
389 of RCU, allowing RCU to work efficiently on machines with
390 large numbers of CPUs. This value must be at least the cube
391 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
392 systems and up to 262,144 for 64-bit systems.
393
394 Select a specific number if testing RCU itself.
395 Take the default if unsure.
396
397config RCU_FANOUT_EXACT
398 bool "Disable tree-based hierarchical RCU auto-balancing"
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700399 depends on TREE_RCU || TREE_PREEMPT_RCU
Mike Travisc903ff82009-01-15 12:28:29 -0800400 default n
401 help
402 This option forces use of the exact RCU_FANOUT value specified,
403 regardless of imbalances in the hierarchy. This is useful for
404 testing RCU itself, and might one day be useful on systems with
405 strong NUMA behavior.
406
407 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
408
409 Say N if unsure.
410
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800411config RCU_FAST_NO_HZ
412 bool "Accelerate last non-dyntick-idle CPU's grace periods"
413 depends on TREE_RCU && NO_HZ && SMP
414 default n
415 help
416 This option causes RCU to attempt to accelerate grace periods
417 in order to allow the final CPU to enter dynticks-idle state
418 more quickly. On the other hand, this option increases the
419 overhead of the dynticks-idle checking, particularly on systems
420 with large numbers of CPUs.
421
422 Say Y if energy efficiency is critically important, particularly
423 if you have relatively few CPUs.
424
425 Say N if you are unsure.
426
Mike Travisc903ff82009-01-15 12:28:29 -0800427config TREE_RCU_TRACE
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700428 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800429 select DEBUG_FS
430 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700431 This option provides tracing for the TREE_RCU and
432 TREE_PREEMPT_RCU implementations, permitting Makefile to
433 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800434
Mike Travisc903ff82009-01-15 12:28:29 -0800435endmenu # "RCU Subsystem"
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700438 tristate "Kernel .config support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 ---help---
440 This option enables the complete Linux kernel ".config" file
441 contents to be saved in the kernel. It provides documentation
442 of which kernel options are used in a running kernel or in an
443 on-disk kernel. This information can be extracted from the kernel
444 image file with the script scripts/extract-ikconfig and used as
445 input to rebuild the current kernel or to build another kernel.
446 It can also be extracted from a running kernel by reading
447 /proc/config.gz if enabled (below).
448
449config IKCONFIG_PROC
450 bool "Enable access to .config through /proc/config.gz"
451 depends on IKCONFIG && PROC_FS
452 ---help---
453 This option enables access to the kernel configuration file
454 through /proc/config.gz.
455
Alistair John Strachan794543a2007-05-08 00:31:15 -0700456config LOG_BUF_SHIFT
457 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
458 range 12 21
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700459 default 17
Alistair John Strachan794543a2007-05-08 00:31:15 -0700460 help
461 Select kernel log buffer size as a power of 2.
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700462 Examples:
463 17 => 128 KB
464 16 => 64 KB
465 15 => 32 KB
466 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700467 13 => 8 KB
468 12 => 4 KB
469
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800470#
471# Architectures with an unreliable sched_clock() should select this:
472#
473config HAVE_UNSTABLE_SCHED_CLOCK
474 bool
475
Li Zefan23964d22009-01-15 13:50:58 -0800476menuconfig CGROUPS
477 boolean "Control Group support"
Kirill A. Shutemov0dea1162010-03-10 15:22:20 -0800478 depends on EVENTFD
Paul Menageddbcc7e2007-10-18 23:39:30 -0700479 help
Li Zefan23964d22009-01-15 13:50:58 -0800480 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800481 use with process control subsystems such as Cpusets, CFS, memory
482 controls or device isolation.
483 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800484 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800485 - Documentation/cgroups/ (features for grouping, isolation
486 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700487
488 Say N if unsure.
489
Li Zefan23964d22009-01-15 13:50:58 -0800490if CGROUPS
491
Paul Menage006cb992007-10-18 23:39:43 -0700492config CGROUP_DEBUG
493 bool "Example debug cgroup subsystem"
494 depends on CGROUPS
Paul Menage418d7d82008-04-29 01:00:05 -0700495 default n
Paul Menage006cb992007-10-18 23:39:43 -0700496 help
497 This option enables a simple cgroup subsystem that
498 exports useful debugging information about the cgroups
Li Zefan23964d22009-01-15 13:50:58 -0800499 framework.
Paul Menage006cb992007-10-18 23:39:43 -0700500
Li Zefan23964d22009-01-15 13:50:58 -0800501 Say N if unsure.
Paul Menage006cb992007-10-18 23:39:43 -0700502
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700503config CGROUP_NS
Li Zefan23964d22009-01-15 13:50:58 -0800504 bool "Namespace cgroup subsystem"
505 depends on CGROUPS
506 help
507 Provides a simple namespace cgroup subsystem to
508 provide hierarchical naming of sets of namespaces,
509 for instance virtual servers and checkpoint/restart
510 jobs.
Serge E. Hallyn858d72e2007-10-18 23:39:45 -0700511
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700512config CGROUP_FREEZER
Li Zefan23964d22009-01-15 13:50:58 -0800513 bool "Freezer cgroup subsystem"
514 depends on CGROUPS
515 help
516 Provides a way to freeze and unfreeze all tasks in a
Matt Helsleydc52ddc2008-10-18 20:27:21 -0700517 cgroup.
518
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700519config CGROUP_DEVICE
520 bool "Device controller for cgroups"
521 depends on CGROUPS && EXPERIMENTAL
522 help
523 Provides a cgroup implementing whitelists for devices which
524 a process in the cgroup can mknod or open.
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526config CPUSETS
527 bool "Cpuset support"
Paul Menagedb7f47c2009-04-02 16:57:55 -0700528 depends on CGROUPS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 help
Randy Dunlapd9fd8a62005-07-27 11:45:11 -0700530 This option will let you create and manage CPUSETs which
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 allow dynamically partitioning a system into sets of CPUs and
532 Memory Nodes and assigning tasks to run only within those sets.
533 This is primarily useful on large SMP or NUMA systems.
534
535 Say N if unsure.
536
Li Zefan23964d22009-01-15 13:50:58 -0800537config PROC_PID_CPUSET
538 bool "Include legacy /proc/<pid>/cpuset file"
539 depends on CPUSETS
540 default y
541
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100542config CGROUP_CPUACCT
543 bool "Simple CPU accounting cgroup subsystem"
544 depends on CGROUPS
545 help
546 Provides a simple Resource Controller for monitoring the
Li Zefan23964d22009-01-15 13:50:58 -0800547 total CPU consumed by the tasks in a cgroup.
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +0100548
Pavel Emelianove552b662008-02-07 00:13:49 -0800549config RESOURCE_COUNTERS
550 bool "Resource counters"
551 help
552 This option enables controller independent resource accounting
Li Zefan23964d22009-01-15 13:50:58 -0800553 infrastructure that works with cgroups.
Pavel Emelianove552b662008-02-07 00:13:49 -0800554 depends on CGROUPS
555
Balbir Singh00f0b822008-03-04 14:28:39 -0800556config CGROUP_MEM_RES_CTLR
557 bool "Memory Resource Controller for Control Groups"
558 depends on CGROUPS && RESOURCE_COUNTERS
Balbir Singhcf475ad2008-04-29 01:00:16 -0700559 select MM_OWNER
Balbir Singh00f0b822008-03-04 14:28:39 -0800560 help
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700561 Provides a memory resource controller that manages both anonymous
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +0100562 memory and page cache. (See Documentation/cgroups/memory.txt)
Balbir Singh00f0b822008-03-04 14:28:39 -0800563
564 Note that setting this option increases fixed memory overhead
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700565 associated with each page of memory in the system. By this,
566 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
567 usage tracking struct at boot. Total amount of this is printed out
568 at boot.
Balbir Singh00f0b822008-03-04 14:28:39 -0800569
570 Only enable when you're ok with these trade offs and really
KAMEZAWA Hiroyuki84ad6d72008-10-29 14:01:06 -0700571 sure you need the memory resource controller. Even when you enable
572 this, you can set "cgroup_disable=memory" at your boot option to
573 disable memory resource controller and you can avoid overheads.
Li Zefanc9d54092009-01-07 18:07:35 -0800574 (and lose benefits of memory resource controller)
Balbir Singh00f0b822008-03-04 14:28:39 -0800575
Balbir Singhcf475ad2008-04-29 01:00:16 -0700576 This config option also selects MM_OWNER config option, which
577 could in turn add some fork/exit overhead.
578
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800579config CGROUP_MEM_RES_CTLR_SWAP
KAMEZAWA Hiroyuki65e0e812010-08-10 18:02:56 -0700580 bool "Memory Resource Controller Swap Extension"
581 depends on CGROUP_MEM_RES_CTLR && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800582 help
583 Add swap management feature to memory resource controller. When you
584 enable this, you can limit mem+swap usage per cgroup. In other words,
585 when you disable this, memory resource controller has no cares to
586 usage of swap...a process can exhaust all of the swap. This extension
587 is useful when you want to avoid exhaustion swap but this itself
588 adds more overheads and consumes memory for remembering information.
589 Especially if you use 32bit system or small memory system, please
590 be careful about enabling this. When memory resource controller
591 is disabled by boot option, this will be automatically disabled and
592 there will be no overhead from this. Even when you set this config=y,
593 if boot option "noswapaccount" is set, swap will not be accounted.
KAMEZAWA Hiroyuki627991a2009-04-02 16:57:47 -0700594 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
595 size is 4096bytes, 512k per 1Gbytes of swap.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800596
Dhaval Giani7c941432010-01-20 13:26:18 +0100597menuconfig CGROUP_SCHED
598 bool "Group CPU scheduler"
599 depends on EXPERIMENTAL && CGROUPS
600 default n
601 help
602 This feature lets CPU scheduler recognize task groups and control CPU
603 bandwidth allocation to such task groups. It uses cgroups to group
604 tasks.
605
606if CGROUP_SCHED
607config FAIR_GROUP_SCHED
608 bool "Group scheduling for SCHED_OTHER"
609 depends on CGROUP_SCHED
610 default CGROUP_SCHED
611
612config RT_GROUP_SCHED
613 bool "Group scheduling for SCHED_RR/FIFO"
614 depends on EXPERIMENTAL
615 depends on CGROUP_SCHED
616 default n
617 help
618 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800619 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100620 schedule realtime tasks for non-root users until you allocate
621 realtime bandwidth for them.
622 See Documentation/scheduler/sched-rt-group.txt for more information.
623
624endif #CGROUP_SCHED
625
Vivek Goyalafc24d42010-04-26 19:27:56 +0200626config BLK_CGROUP
627 tristate "Block IO controller"
628 depends on CGROUPS && BLOCK
629 default n
630 ---help---
631 Generic block IO controller cgroup interface. This is the common
632 cgroup interface which should be used by various IO controlling
633 policies.
634
635 Currently, CFQ IO scheduler uses it to recognize task groups and
636 control disk bandwidth allocation (proportional time slice allocation)
637 to such task groups.
638
639 This option only enables generic Block IO controller infrastructure.
640 One needs to also enable actual IO controlling logic in CFQ for it
641 to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
642
643 See Documentation/cgroups/blkio-controller.txt for more information.
644
645config DEBUG_BLK_CGROUP
646 bool "Enable Block IO controller debugging"
647 depends on BLK_CGROUP
648 default n
649 ---help---
650 Enable some debugging help. Currently it exports additional stat
651 files in a cgroup which can be useful for debugging.
652
Li Zefan23964d22009-01-15 13:50:58 -0800653endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800654
Li Zefan23964d22009-01-15 13:50:58 -0800655config MM_OWNER
656 bool
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800657
Kay Sievers88a22c92006-09-14 11:23:28 +0200658config SYSFS_DEPRECATED
Ingo Molnard47846c2008-03-04 14:54:47 +0100659 bool
660
661config SYSFS_DEPRECATED_V2
Uwe Kleine-König9e9868a2009-12-03 19:58:00 +0100662 bool "enable deprecated sysfs features to support old userspace tools"
Randy Dunlap9148fe82007-12-31 10:05:34 -0800663 depends on SYSFS
Kay Sieversf6ee6492009-04-16 19:56:37 +0200664 default n
Ingo Molnard47846c2008-03-04 14:54:47 +0100665 select SYSFS_DEPRECATED
Kay Sievers88a22c92006-09-14 11:23:28 +0200666 help
Kay Sieversfce3e802008-11-01 14:03:00 +0100667 This option switches the layout of sysfs to the deprecated
Kay Sieversf6ee6492009-04-16 19:56:37 +0200668 version. Do not use it on recent distributions.
Kay Sievers88a22c92006-09-14 11:23:28 +0200669
Kay Sieversfce3e802008-11-01 14:03:00 +0100670 The current sysfs layout features a unified device tree at
671 /sys/devices/, which is able to express a hierarchy between
672 class devices. If the deprecated option is set to Y, the
673 unified device tree is split into a bus device tree at
674 /sys/devices/ and several individual class device trees at
675 /sys/class/. The class and bus devices will be connected by
676 "<subsystem>:<name>" and the "device" links. The "block"
677 class devices, will not show up in /sys/class/block/. Some
678 subsystems will suppress the creation of some devices which
679 depend on the unified device tree.
Kay Sievers88a22c92006-09-14 11:23:28 +0200680
Kay Sieversfce3e802008-11-01 14:03:00 +0100681 This option is not a pure compatibility option that can
682 be safely enabled on newer distributions. It will change the
683 layout of sysfs to the non-extensible deprecated version,
684 and disable some features, which can not be exported without
685 confusing older userspace tools. Since 2007/2008 all major
686 distributions do not enable this option, and ship no tools which
687 depend on the deprecated layout or this option.
688
689 If you are using a new kernel on an older distribution, or use
690 older userspace tools, you might need to say Y here. Do not say Y,
691 if the original kernel, that came with your distribution, has
692 this option set to N.
Kay Sievers88a22c92006-09-14 11:23:28 +0200693
Jens Axboeb86ff982006-03-23 19:56:55 +0100694config RELAY
695 bool "Kernel->user space relay support (formerly relayfs)"
696 help
697 This option enables support for relay interface support in
698 certain file systems (such as debugfs).
699 It is designed to provide an efficient mechanism for tools and
700 facilities to relay large amounts of data from kernel space to
701 user space.
702
703 If unsure, say N.
704
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800705config NAMESPACES
706 bool "Namespaces support" if EMBEDDED
707 default !EMBEDDED
708 help
709 Provides the way to make tasks work with different objects using
710 the same id. For example same IPC id may refer to different objects
711 or same user id or pid may refer to different tasks when used in
712 different namespaces.
713
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800714config UTS_NS
715 bool "UTS namespace"
716 depends on NAMESPACES
717 help
718 In this namespace tasks see different info provided with the
719 uname() system call
720
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800721config IPC_NS
722 bool "IPC namespace"
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700723 depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800724 help
725 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700726 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800727
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800728config USER_NS
729 bool "User namespace (EXPERIMENTAL)"
730 depends on NAMESPACES && EXPERIMENTAL
731 help
732 This allows containers, i.e. vservers, to use user namespaces
733 to provide different user info for different servers.
734 If unsure, say N.
735
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800736config PID_NS
737 bool "PID Namespaces (EXPERIMENTAL)"
738 default n
739 depends on NAMESPACES && EXPERIMENTAL
740 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300741 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100742 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800743 pid namespaces. This is a building block of containers.
744
745 Unless you want to work with an experimental feature
746 say N here.
747
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800748config NET_NS
749 bool "Network namespace"
750 default n
751 depends on NAMESPACES && EXPERIMENTAL && NET
752 help
753 Allow user space to create what appear to be multiple instances
754 of the network stack.
755
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800756config BLK_DEV_INITRD
757 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
758 depends on BROKEN || !FRV
759 help
760 The initial RAM filesystem is a ramfs which is loaded by the
761 boot loader (loadlin or lilo) and that is mounted as root
762 before the normal boot procedure. It is typically used to
763 load modules needed to mount the "real" root file system,
764 etc. See <file:Documentation/initrd.txt> for details.
765
766 If RAM disk support (BLK_DEV_RAM) is also included, this
767 also enables initial RAM disk (initrd) support and adds
768 15 Kbytes (more on some other architectures) to the kernel size.
769
770 If unsure say Y.
771
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800772if BLK_DEV_INITRD
773
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200774source "usr/Kconfig"
775
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800776endif
777
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800778config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +0200779 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800780 default y
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800781 help
782 Enabling this option will pass "-Os" instead of "-O2" to gcc
783 resulting in a smaller kernel.
784
jkacur775a7222008-07-16 00:31:16 +0200785 If unsure, say Y.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -0800786
Randy Dunlap08470622006-09-30 23:28:13 -0700787config SYSCTL
788 bool
789
Randy Dunlapb943c462009-03-10 12:55:46 -0700790config ANON_INODES
791 bool
792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793menuconfig EMBEDDED
794 bool "Configure standard kernel features (for small systems)"
795 help
796 This option allows certain base kernel options and settings
797 to be disabled or tweaked. This is for specialized
798 environments which can tolerate a "non-standard" kernel.
799 Only use this if you really know what you are doing.
800
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700801config UID16
802 bool "Enable 16-bit UID system calls" if EMBEDDED
David S. Miller09337f52008-04-26 03:17:12 -0700803 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 -0700804 default y
805 help
806 This enables the legacy 16-bit UID syscall wrappers.
807
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700808config SYSCTL_SYSCALL
Randy Dunlap08470622006-09-30 23:28:13 -0700809 bool "Sysctl syscall support" if EMBEDDED
Eric W. Biederman26a70342009-11-05 05:26:41 -0800810 depends on PROC_SYSCTL
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800811 default y
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700812 select SYSCTL
813 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800814 sys_sysctl uses binary paths that have been found challenging
815 to properly maintain and use. The interface in /proc/sys
816 using paths with ascii names is now the primary path to this
817 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700818
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800819 Almost nothing using the binary sysctl interface so if you are
820 trying to save some space it is probably safe to disable this,
821 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -0700822
Eric W. Biederman13bb7e32006-11-08 17:44:51 -0800823 If unsure say Y here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -0700824
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825config KALLSYMS
Jesper Juhl979c6a12006-12-12 19:25:11 +0100826 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 default y
828 help
829 Say Y here to let the kernel print out symbolic crash information and
830 symbolic stack backtraces. This increases the size of the kernel
831 somewhat, as all symbols have to be loaded into the kernel image.
832
833config KALLSYMS_ALL
834 bool "Include all symbols in kallsyms"
835 depends on DEBUG_KERNEL && KALLSYMS
836 help
837 Normally kallsyms only contains the symbols of functions, for nicer
838 OOPS messages. Some debuggers can use kallsyms for other
Jesper Juhlf9f97bc2005-07-20 05:43:05 +0200839 symbols too: say Y here to include all symbols, if you need them
840 and you don't care about adding 300k to the size of your kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
842 Say N.
843
844config KALLSYMS_EXTRA_PASS
845 bool "Do an extra kallsyms pass"
846 depends on KALLSYMS
847 help
848 If kallsyms is not working correctly, the build will fail with
849 inconsistent kallsyms data. If that occurs, log a bug report and
850 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
851 Always say N here unless you find a bug in kallsyms, which must be
852 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
853 you wait for kallsyms to be fixed.
854
Matt Mackalld59745c2005-05-01 08:59:02 -0700855
Greg Kroah-Hartman712f47c2005-11-16 11:27:07 -0800856config HOTPLUG
857 bool "Support for hot-pluggable devices" if EMBEDDED
858 default y
859 help
860 This option is provided for the case where no hotplug or uevent
861 capabilities is wanted by the kernel. You should only consider
862 disabling this option for embedded systems that do not use modules, a
863 dynamic /dev tree, or dynamic device discovery. Just say Y.
864
Matt Mackalld59745c2005-05-01 08:59:02 -0700865config PRINTK
866 default y
867 bool "Enable support for printk" if EMBEDDED
868 help
869 This option enables normal printk support. Removing it
870 eliminates most of the message strings from the kernel image
871 and makes the kernel more or less silent. As this makes it
872 very difficult to diagnose system problems, saying N here is
873 strongly discouraged.
874
Matt Mackallc8538a72005-05-01 08:59:01 -0700875config BUG
876 bool "BUG() support" if EMBEDDED
877 default y
878 help
879 Disabling this option eliminates support for BUG and WARN, reducing
880 the size of your kernel image and potentially quietly ignoring
881 numerous fatal conditions. You should only consider disabling this
882 option for embedded systems with no facilities for reporting errors.
883 Just say Y.
884
Matt Mackall708e9a72006-01-08 01:05:25 -0800885config ELF_CORE
886 default y
887 bool "Enable ELF core dumps" if EMBEDDED
888 help
889 Enable support for generating core dumps. Disabling saves about 4k.
890
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +0200891config PCSPKR_PLATFORM
892 bool "Enable PC-Speaker support" if EMBEDDED
893 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
894 default y
895 help
896 This option allows to disable the internal PC-Speaker
897 support, saving some memory.
898
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899config BASE_FULL
900 default y
901 bool "Enable full-sized data structures for core" if EMBEDDED
902 help
903 Disabling this option reduces the size of miscellaneous core
904 kernel data structures. This saves memory on small machines,
905 but may reduce performance.
906
907config FUTEX
908 bool "Enable futex support" if EMBEDDED
909 default y
Ingo Molnar23f78d42006-06-27 02:54:53 -0700910 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 help
912 Disabling this option will cause the kernel to be built without
913 support for "fast userspace mutexes". The resulting kernel may not
914 run glibc-based applications correctly.
915
916config EPOLL
917 bool "Enable eventpoll support" if EMBEDDED
918 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700919 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 help
921 Disabling this option will cause the kernel to be built without
922 support for epoll family of system calls.
923
Davide Libenzifba2afa2007-05-10 22:23:13 -0700924config SIGNALFD
925 bool "Enable signalfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700926 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -0700927 default y
928 help
929 Enable the signalfd() system call that allows to receive signals
930 on a file descriptor.
931
932 If unsure, say Y.
933
Davide Libenzib215e282007-05-10 22:23:16 -0700934config TIMERFD
935 bool "Enable timerfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700936 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -0700937 default y
938 help
939 Enable the timerfd() system call that allows to receive timer
940 events on a file descriptor.
941
942 If unsure, say Y.
943
Davide Libenzie1ad7462007-05-10 22:23:19 -0700944config EVENTFD
945 bool "Enable eventfd() system call" if EMBEDDED
Adrian Bunk448e3ce2007-07-31 00:39:10 -0700946 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -0700947 default y
948 help
949 Enable the eventfd() system call that allows to receive both
950 kernel notification (ie. KAIO) or userspace notifications.
951
952 If unsure, say Y.
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954config SHMEM
955 bool "Use full shmem filesystem" if EMBEDDED
956 default y
957 depends on MMU
958 help
959 The shmem is an internal filesystem used to manage shared memory.
960 It is backed by swap and manages resource limits. It is also exported
961 to userspace as tmpfs if TMPFS is enabled. Disabling this
962 option replaces shmem and tmpfs with the much simpler ramfs code,
963 which may be appropriate on small systems without swap.
964
Thomas Petazzoniebf3f092008-10-15 22:05:12 -0700965config AIO
966 bool "Enable AIO support" if EMBEDDED
967 default y
968 help
969 This option enables POSIX asynchronous I/O which may by used
970 by some high performance threaded applications. Disabling
971 this option saves about 7k.
972
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200973config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +0100974 bool
Mike Frysinger018df722009-06-12 13:17:43 -0400975 help
976 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100977
Peter Zijlstra906010b2009-09-21 16:08:49 +0200978config PERF_USE_VMALLOC
979 bool
980 help
981 See tools/perf/design.txt for details
982
Ingo Molnar57c0c152009-09-21 12:20:38 +0200983menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +0100984
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200985config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +0200986 bool "Kernel performance events and counters"
987 default y if (PROFILING || PERF_COUNTERS)
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200988 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +0100989 select ANON_INODES
Thomas Gleixner0793a612008-12-04 20:12:29 +0100990 help
Ingo Molnar57c0c152009-09-21 12:20:38 +0200991 Enable kernel support for various performance events provided
992 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +0100993
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -0200994 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +0200995 use of generic tracepoints.
996
997 Most modern CPUs support performance events via performance
998 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +0100999 types of hw events: such as instructions executed, cachemisses
1000 suffered, or branches mis-predicted - without slowing down the
1001 kernel or applications. These registers can also trigger interrupts
1002 when a threshold number of events have passed - and can thus be
1003 used to profile the code that runs on that CPU.
1004
Ingo Molnar57c0c152009-09-21 12:20:38 +02001005 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001006 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001007 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001008 provides per task and per CPU counters, and it provides event
1009 capabilities on top of those.
1010
1011 Say Y if unsure.
1012
Ingo Molnar57c0c152009-09-21 12:20:38 +02001013config PERF_COUNTERS
1014 bool "Kernel performance counters (old config option)"
1015 depends on HAVE_PERF_EVENTS
1016 help
1017 This config has been obsoleted by the PERF_EVENTS
1018 config option - please see that one for details.
1019
1020 It has no effect on the kernel whether you enable
1021 it or not, it is a compatibility placeholder.
1022
1023 Say N if unsure.
1024
Peter Zijlstra906010b2009-09-21 16:08:49 +02001025config DEBUG_PERF_USE_VMALLOC
1026 default n
1027 bool "Debug: use vmalloc to back perf mmap() buffers"
1028 depends on PERF_EVENTS && DEBUG_KERNEL
1029 select PERF_USE_VMALLOC
1030 help
1031 Use vmalloc memory to back perf mmap() buffers.
1032
1033 Mostly useful for debugging the vmalloc code on platforms
1034 that don't require it.
1035
1036 Say N if unsure.
1037
Thomas Gleixner0793a612008-12-04 20:12:29 +01001038endmenu
1039
Christoph Lameterf8891e52006-06-30 01:55:45 -07001040config VM_EVENT_COUNTERS
1041 default y
1042 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1043 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001044 VM event counters are needed for event counts to be shown.
1045 This option allows the disabling of the VM event counters
1046 on EMBEDDED systems. /proc/vmstat will only show page counts
1047 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001048
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001049config PCI_QUIRKS
1050 default y
Geert Uytterhoeven61cfc7e2008-10-22 08:53:25 +02001051 bool "Enable PCI quirk workarounds" if EMBEDDED
1052 depends on PCI
Thomas Petazzoni3d137312008-08-19 10:28:24 +02001053 help
1054 This enables workarounds for various PCI chipset
1055 bugs/quirks. Disable this only if your target machine is
1056 unaffected by PCI quirks.
1057
Christoph Lameter41ecc552007-05-09 02:32:44 -07001058config SLUB_DEBUG
1059 default y
1060 bool "Enable SLUB debugging support" if EMBEDDED
Christoph Lameterf6acb632008-04-29 16:16:06 -07001061 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001062 help
1063 SLUB has extensive debug support features. Disabling these can
1064 result in significant savings in code size. This also disables
1065 SLUB sysfs support. /sys/slab will not exist and there will be
1066 no support for cache validation etc.
1067
Randy Dunlapb943c462009-03-10 12:55:46 -07001068config COMPAT_BRK
1069 bool "Disable heap randomization"
1070 default y
1071 help
1072 Randomizing heap placement makes heap exploits harder, but it
1073 also breaks ancient binaries (including anything libc5 based).
1074 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001075 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001076 /proc/sys/kernel/randomize_va_space to 2.
1077
1078 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1079
Christoph Lameter81819f02007-05-06 14:49:36 -07001080choice
1081 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001082 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001083 help
1084 This option allows to select a slab allocator.
1085
1086config SLAB
1087 bool "SLAB"
1088 help
1089 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001090 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001091 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001092
1093config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001094 bool "SLUB (Unqueued Allocator)"
1095 help
1096 SLUB is a slab allocator that minimizes cache line usage
1097 instead of managing queues of cached objects (SLAB approach).
1098 Per cpu caching is realized using slabs of objects instead
1099 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001100 and has enhanced diagnostics. SLUB is the default choice for
1101 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001102
1103config SLOB
Paul Mundt84a01c22007-07-15 23:38:24 -07001104 depends on EMBEDDED
Christoph Lameter81819f02007-05-06 14:49:36 -07001105 bool "SLOB (Simple Allocator)"
1106 help
Matt Mackall37291452008-02-04 22:29:38 -08001107 SLOB replaces the stock allocator with a drastically simpler
1108 allocator. SLOB is generally more space efficient but
1109 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001110
1111endchoice
1112
Jie Zhangea637632009-12-14 18:00:02 -08001113config MMAP_ALLOW_UNINITIALIZED
1114 bool "Allow mmapped anonymous memory to be uninitialized"
1115 depends on EMBEDDED && !MMU
1116 default n
1117 help
1118 Normally, and according to the Linux spec, anonymous memory obtained
1119 from mmap() has it's contents cleared before it is passed to
1120 userspace. Enabling this config option allows you to request that
1121 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1122 providing a huge performance boost. If this option is not enabled,
1123 then the flag will be ignored.
1124
1125 This is taken advantage of by uClibc's malloc(), and also by
1126 ELF-FDPIC binfmt's brk and stack allocator.
1127
1128 Because of the obvious security issues, this option should only be
1129 enabled on embedded devices where you control what is run in
1130 userspace. Since that isn't generally a problem on no-MMU systems,
1131 it is normally safe to say Y here.
1132
1133 See Documentation/nommu-mmap.txt for more information.
1134
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001135config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001136 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001137 help
1138 Say Y here to enable the extended profiling support mechanisms used
1139 by profilers such as OProfile.
1140
Ingo Molnar5f87f112008-07-23 14:15:22 +02001141#
1142# Place an empty function call at each tracepoint site. Can be
1143# dynamically changed for a probe function.
1144#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001145config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001146 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001147
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001148source "arch/Kconfig"
1149
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150endmenu # General setup
1151
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001152config HAVE_GENERIC_DMA_COHERENT
1153 bool
1154 default n
1155
Linus Torvalds158a9622008-01-02 13:04:48 -08001156config SLABINFO
1157 bool
1158 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001159 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001160 default y
1161
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001162config RT_MUTEXES
1163 boolean
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001164
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165config BASE_SMALL
1166 int
1167 default 0 if BASE_FULL
1168 default 1 if !BASE_FULL
1169
Jan Engelhardt66da5732007-07-15 23:39:29 -07001170menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 bool "Enable loadable module support"
1172 help
1173 Kernel modules are small pieces of compiled code which can
1174 be inserted in the running kernel, rather than being
1175 permanently built into the kernel. You use the "modprobe"
1176 tool to add (and sometimes remove) them. If you say Y here,
1177 many parts of the kernel can be built as modules (by
1178 answering M instead of Y where indicated): this is most
1179 useful for infrequently used options which are not required
1180 for booting. For more information, see the man pages for
1181 modprobe, lsmod, modinfo, insmod and rmmod.
1182
1183 If you say Y here, you will need to run "make
1184 modules_install" to put the modules under /lib/modules/
1185 where modprobe can find them (you may need to be root to do
1186 this).
1187
1188 If unsure, say Y.
1189
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001190if MODULES
1191
Linus Torvalds826e4502008-05-04 17:04:16 -07001192config MODULE_FORCE_LOAD
1193 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001194 default n
1195 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001196 Allow loading of modules without version information (ie. modprobe
1197 --force). Forced module loading sets the 'F' (forced) taint flag and
1198 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001199
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200config MODULE_UNLOAD
1201 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 help
1203 Without this option you will not be able to unload any
1204 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001205 anyway), which makes your kernel smaller, faster
1206 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207
1208config MODULE_FORCE_UNLOAD
1209 bool "Forced module unloading"
1210 depends on MODULE_UNLOAD && EXPERIMENTAL
1211 help
1212 This option allows you to force a module to unload, even if the
1213 kernel believes it is unsafe: the kernel will remove the module
1214 without waiting for anyone to stop using it (using the -f option to
1215 rmmod). This is mainly for kernel developers and desperate users.
1216 If unsure, say N.
1217
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001219 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 help
1221 Usually, you have to use modules compiled with your kernel.
1222 Saying Y here makes it sometimes possible to use modules
1223 compiled for different kernels, by adding enough information
1224 to the modules to (hopefully) spot any changes which would
1225 make them incompatible with the kernel you are running. If
1226 unsure, say N.
1227
1228config MODULE_SRCVERSION_ALL
1229 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 help
1231 Modules which contain a MODULE_VERSION get an extra "srcversion"
1232 field inserted into their modinfo section, which contains a
1233 sum of the source files which made it. This helps maintainers
1234 see exactly which source was used to build a module (since
1235 others sometimes change the module source without updating
1236 the version). With this option, such a "srcversion" field
1237 will be created for all modules. If unsure, say N.
1238
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001239endif # MODULES
1240
Rusty Russell98a79d62008-12-13 21:19:41 +10301241config INIT_ALL_POSSIBLE
1242 bool
1243 help
1244 Back when each arch used to define their own cpu_online_map and
1245 cpu_possible_map, some of them chose to initialize cpu_possible_map
1246 with all 1s, and others with all 0s. When they were centralised,
1247 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001248 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301249
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250config STOP_MACHINE
1251 bool
1252 default y
1253 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1254 help
1255 Need stop_machine() primitive.
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001256
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001257source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001258
1259config PREEMPT_NOTIFIERS
1260 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001261
Steffen Klassert16295be2010-01-06 19:47:10 +11001262config PADATA
1263 depends on SMP
1264 bool
1265
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001266source "kernel/Kconfig.locks"