module: be more picky about allowing missing module versions
[linux-2.6-block.git] / init / Kconfig
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1config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
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9config DEFCONFIG_LIST
10 string
b2670eac 11 depends on !UML
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12 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "arch/$ARCH/defconfig"
17
ff0cfc66 18menu "General setup"
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19
20config EXPERIMENTAL
21 bool "Prompt for development and/or incomplete code/drivers"
22 ---help---
23 Some of the various things that Linux supports (such as network
24 drivers, file systems, network protocols, etc.) can be in a state
25 of development where the functionality, stability, or the level of
26 testing is not yet high enough for general use. This is usually
27 known as the "alpha-test" phase among developers. If a feature is
28 currently in alpha-test, then the developers usually discourage
29 uninformed widespread use of this feature by the general public to
30 avoid "Why doesn't this work?" type mail messages. However, active
31 testing and use of these systems is welcomed. Just be aware that it
32 may not meet the normal level of reliability or it may fail to work
33 in some special cases. Detailed bug reports from people familiar
34 with the kernel internals are usually welcomed by the developers
35 (before submitting bug reports, please read the documents
36 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
37 <file:Documentation/BUG-HUNTING>, and
38 <file:Documentation/oops-tracing.txt> in the kernel source).
39
40 This option will also make obsoleted drivers available. These are
41 drivers that have been replaced by something else, and/or are
42 scheduled to be removed in a future kernel release.
43
44 Unless you intend to help test and develop a feature or driver that
45 falls into this category, or you have a situation that requires
46 using these features, you should probably say N here, which will
47 cause the configurator to present you with fewer choices. If
48 you say Y here, you will be offered the choice of using features or
49 drivers that are currently considered to be in the alpha-test phase.
50
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51config BROKEN
52 bool
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53
54config BROKEN_ON_SMP
55 bool
56 depends on BROKEN || !SMP
57 default y
58
59config LOCK_KERNEL
60 bool
61 depends on SMP || PREEMPT
62 default y
63
64config INIT_ENV_ARG_LIMIT
65 int
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66 default 32 if !UML
67 default 128 if UML
1da177e4 68 help
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69 Maximum of each of the number of arguments and environment
70 variables passed to init from the kernel command line.
1da177e4 71
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72
73config LOCALVERSION
74 string "Local version - append to kernel release"
75 help
76 Append an extra string to the end of your kernel version.
77 This will show up when you type uname, for example.
78 The string you set here will be appended after the contents of
79 any files with a filename matching localversion* in your
80 object and source tree, in that order. Your total string can
81 be a maximum of 64 characters.
82
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83config LOCALVERSION_AUTO
84 bool "Automatically append version information to the version string"
85 default y
86 help
87 This will try to automatically determine if the current tree is a
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88 release tree by looking for git tags that belong to the current
89 top of tree revision.
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90
91 A string of the format -gxxxxxxxx will be added to the localversion
6e5a5420 92 if a git-based tree is found. The string generated by this will be
aaebf433 93 appended after any matching localversion* files, and after the value
6e5a5420 94 set in CONFIG_LOCALVERSION.
aaebf433 95
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96 (The actual string used here is the first eight characters produced
97 by running the command:
98
99 $ git rev-parse --verify HEAD
100
101 which is done within the script "scripts/setlocalversion".)
aaebf433 102
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103config SWAP
104 bool "Support for paging of anonymous memory (swap)"
9361401e 105 depends on MMU && BLOCK
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106 default y
107 help
108 This option allows you to choose whether you want to have support
92c3504e 109 for so called swap devices or swap files in your kernel that are
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110 used to provide more virtual memory than the actual RAM present
111 in your computer. If unsure say Y.
112
113config SYSVIPC
114 bool "System V IPC"
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115 ---help---
116 Inter Process Communication is a suite of library functions and
117 system calls which let processes (running programs) synchronize and
118 exchange information. It is generally considered to be a good thing,
119 and some programs won't run unless you say Y here. In particular, if
120 you want to run the DOS emulator dosemu under Linux (read the
121 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
122 you'll need to say Y here.
123
124 You can find documentation about IPC with "info ipc" and also in
125 section 6.4 of the Linux Programmer's Guide, available from
126 <http://www.tldp.org/guides.html>.
127
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128config SYSVIPC_SYSCTL
129 bool
130 depends on SYSVIPC
131 depends on SYSCTL
132 default y
133
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134config POSIX_MQUEUE
135 bool "POSIX Message Queues"
136 depends on NET && EXPERIMENTAL
137 ---help---
138 POSIX variant of message queues is a part of IPC. In POSIX message
139 queues every message has a priority which decides about succession
140 of receiving it by a process. If you want to compile and run
141 programs written e.g. for Solaris with use of its POSIX message
b0e37650 142 queues (functions mq_*) say Y here.
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143
144 POSIX message queues are visible as a filesystem called 'mqueue'
145 and can be mounted somewhere if you want to do filesystem
146 operations on message queues.
147
148 If unsure, say Y.
149
150config BSD_PROCESS_ACCT
151 bool "BSD Process Accounting"
152 help
153 If you say Y here, a user level program will be able to instruct the
154 kernel (via a special system call) to write process accounting
155 information to a file: whenever a process exits, information about
156 that process will be appended to the file by the kernel. The
157 information includes things such as creation time, owning user,
158 command name, memory usage, controlling terminal etc. (the complete
159 list is in the struct acct in <file:include/linux/acct.h>). It is
160 up to the user level program to do useful things with this
161 information. This is generally a good idea, so say Y.
162
163config BSD_PROCESS_ACCT_V3
164 bool "BSD Process Accounting version 3 file format"
165 depends on BSD_PROCESS_ACCT
166 default n
167 help
168 If you say Y here, the process accounting information is written
169 in a new file format that also logs the process IDs of each
170 process and it's parent. Note that this file format is incompatible
171 with previous v0/v1/v2 file formats, so you will need updated tools
172 for processing it. A preliminary version of these tools is available
173 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
174
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175config TASKSTATS
176 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
177 depends on NET
178 default n
179 help
180 Export selected statistics for tasks/processes through the
181 generic netlink interface. Unlike BSD process accounting, the
182 statistics are available during the lifetime of tasks/processes as
183 responses to commands. Like BSD accounting, they are sent to user
184 space on task exit.
185
186 Say N if unsure.
187
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188config TASK_DELAY_ACCT
189 bool "Enable per-task delay accounting (EXPERIMENTAL)"
6f44993f 190 depends on TASKSTATS
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191 help
192 Collect information on time spent by a task waiting for system
193 resources like cpu, synchronous block I/O completion and swapping
194 in pages. Such statistics can help in setting a task's priorities
195 relative to other tasks for cpu, io, rss limits etc.
196
197 Say N if unsure.
198
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199config TASK_XACCT
200 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
201 depends on TASKSTATS
202 help
203 Collect extended task accounting data and send the data
204 to userland for processing over the taskstats interface.
205
206 Say N if unsure.
207
208config TASK_IO_ACCOUNTING
209 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
210 depends on TASK_XACCT
211 help
212 Collect information on the number of bytes of storage I/O which this
213 task has caused.
214
215 Say N if unsure.
216
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217config AUDIT
218 bool "Auditing support"
804a6a49 219 depends on NET
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220 help
221 Enable auditing infrastructure that can be used with another
222 kernel subsystem, such as SELinux (which requires this for
223 logging of avc messages output). Does not do system-call
224 auditing without CONFIG_AUDITSYSCALL.
225
226config AUDITSYSCALL
227 bool "Enable system-call auditing support"
1322b9de 228 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
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229 default y if SECURITY_SELINUX
230 help
231 Enable low-overhead system-call auditing infrastructure that
232 can be used independently or with another kernel subsystem,
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233 such as SELinux. To use audit's filesystem watch feature, please
234 ensure that INOTIFY is configured.
1da177e4 235
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236config AUDIT_TREE
237 def_bool y
238 depends on AUDITSYSCALL && INOTIFY
239
1da177e4 240config IKCONFIG
f2443ab6 241 tristate "Kernel .config support"
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242 ---help---
243 This option enables the complete Linux kernel ".config" file
244 contents to be saved in the kernel. It provides documentation
245 of which kernel options are used in a running kernel or in an
246 on-disk kernel. This information can be extracted from the kernel
247 image file with the script scripts/extract-ikconfig and used as
248 input to rebuild the current kernel or to build another kernel.
249 It can also be extracted from a running kernel by reading
250 /proc/config.gz if enabled (below).
251
252config IKCONFIG_PROC
253 bool "Enable access to .config through /proc/config.gz"
254 depends on IKCONFIG && PROC_FS
255 ---help---
256 This option enables access to the kernel configuration file
257 through /proc/config.gz.
258
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259config LOG_BUF_SHIFT
260 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
261 range 12 21
f17a32e9 262 default 17
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263 help
264 Select kernel log buffer size as a power of 2.
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265 Examples:
266 17 => 128 KB
267 16 => 64 KB
268 15 => 32 KB
269 14 => 16 KB
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270 13 => 8 KB
271 12 => 4 KB
272
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273config CGROUPS
274 bool "Control Group support"
275 help
276 This option will let you use process cgroup subsystems
277 such as Cpusets
278
279 Say N if unsure.
280
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281config CGROUP_DEBUG
282 bool "Example debug cgroup subsystem"
283 depends on CGROUPS
418d7d87 284 default n
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285 help
286 This option enables a simple cgroup subsystem that
287 exports useful debugging information about the cgroups
288 framework
289
290 Say N if unsure
291
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292config CGROUP_NS
293 bool "Namespace cgroup subsystem"
294 depends on CGROUPS
295 help
296 Provides a simple namespace cgroup subsystem to
297 provide hierarchical naming of sets of namespaces,
298 for instance virtual servers and checkpoint/restart
299 jobs.
300
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301config CGROUP_DEVICE
302 bool "Device controller for cgroups"
303 depends on CGROUPS && EXPERIMENTAL
304 help
305 Provides a cgroup implementing whitelists for devices which
306 a process in the cgroup can mknod or open.
307
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308config CPUSETS
309 bool "Cpuset support"
8793d854 310 depends on SMP && CGROUPS
1da177e4 311 help
d9fd8a6d 312 This option will let you create and manage CPUSETs which
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313 allow dynamically partitioning a system into sets of CPUs and
314 Memory Nodes and assigning tasks to run only within those sets.
315 This is primarily useful on large SMP or NUMA systems.
316
317 Say N if unsure.
318
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319#
320# Architectures with an unreliable sched_clock() should select this:
321#
322config HAVE_UNSTABLE_SCHED_CLOCK
323 bool
324
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325config GROUP_SCHED
326 bool "Group CPU scheduler"
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327 depends on EXPERIMENTAL
328 default n
29f59db3 329 help
fb615581 330 This feature lets CPU scheduler recognize task groups and control CPU
9b5b7751 331 bandwidth allocation to such task groups.
29f59db3 332
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333config FAIR_GROUP_SCHED
334 bool "Group scheduling for SCHED_OTHER"
335 depends on GROUP_SCHED
aac6abca 336 default GROUP_SCHED
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337
338config RT_GROUP_SCHED
339 bool "Group scheduling for SCHED_RR/FIFO"
340 depends on EXPERIMENTAL
341 depends on GROUP_SCHED
342 default n
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343 help
344 This feature lets you explicitly allocate real CPU bandwidth
345 to users or control groups (depending on the "Basis for grouping tasks"
346 setting below. If enabled, it will also make it impossible to
347 schedule realtime tasks for non-root users until you allocate
348 realtime bandwidth for them.
349 See Documentation/sched-rt-group.txt for more information.
052f1dc7 350
24e377a8 351choice
052f1dc7 352 depends on GROUP_SCHED
24e377a8 353 prompt "Basis for grouping tasks"
052f1dc7 354 default USER_SCHED
24e377a8 355
052f1dc7 356config USER_SCHED
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357 bool "user id"
358 help
359 This option will choose userid as the basis for grouping
360 tasks, thus providing equal CPU bandwidth to each user.
24e377a8 361
052f1dc7 362config CGROUP_SCHED
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363 bool "Control groups"
364 depends on CGROUPS
365 help
366 This option allows you to create arbitrary task groups
367 using the "cgroup" pseudo filesystem and control
368 the cpu bandwidth allocated to each such task group.
369 Refer to Documentation/cgroups.txt for more information
370 on "cgroup" pseudo filesystem.
371
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372endchoice
373
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374config CGROUP_CPUACCT
375 bool "Simple CPU accounting cgroup subsystem"
376 depends on CGROUPS
377 help
378 Provides a simple Resource Controller for monitoring the
379 total CPU consumed by the tasks in a cgroup
380
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381config RESOURCE_COUNTERS
382 bool "Resource counters"
383 help
384 This option enables controller independent resource accounting
385 infrastructure that works with cgroups
386 depends on CGROUPS
387
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388config MM_OWNER
389 bool
390
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391config CGROUP_MEM_RES_CTLR
392 bool "Memory Resource Controller for Control Groups"
393 depends on CGROUPS && RESOURCE_COUNTERS
cf475ad2 394 select MM_OWNER
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395 help
396 Provides a memory resource controller that manages both page cache and
397 RSS memory.
398
399 Note that setting this option increases fixed memory overhead
400 associated with each page of memory in the system by 4/8 bytes
401 and also increases cache misses because struct page on many 64bit
402 systems will not fit into a single cache line anymore.
403
404 Only enable when you're ok with these trade offs and really
405 sure you need the memory resource controller.
406
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407 This config option also selects MM_OWNER config option, which
408 could in turn add some fork/exit overhead.
409
88a22c98 410config SYSFS_DEPRECATED
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411 bool
412
413config SYSFS_DEPRECATED_V2
88a22c98 414 bool "Create deprecated sysfs files"
9148fe87 415 depends on SYSFS
88a22c98 416 default y
d47846c5 417 select SYSFS_DEPRECATED
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418 help
419 This option creates deprecated symlinks such as the
420 "device"-link, the <subsystem>:<name>-link, and the
421 "bus"-link. It may also add deprecated key in the
422 uevent environment.
423 None of these features or values should be used today, as
424 they export driver core implementation details to userspace
425 or export properties which can't be kept stable across kernel
426 releases.
427
428 If enabled, this option will also move any device structures
3dde6ad8 429 that belong to a class, back into the /sys/class hierarchy, in
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430 order to support older versions of udev and some userspace
431 programs.
88a22c98 432
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433 If you are using a distro with the most recent userspace
434 packages, it should be safe to say N here.
88a22c98 435
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436config PROC_PID_CPUSET
437 bool "Include legacy /proc/<pid>/cpuset file"
438 depends on CPUSETS
439 default y
440
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441config RELAY
442 bool "Kernel->user space relay support (formerly relayfs)"
443 help
444 This option enables support for relay interface support in
445 certain file systems (such as debugfs).
446 It is designed to provide an efficient mechanism for tools and
447 facilities to relay large amounts of data from kernel space to
448 user space.
449
450 If unsure, say N.
451
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452config NAMESPACES
453 bool "Namespaces support" if EMBEDDED
454 default !EMBEDDED
455 help
456 Provides the way to make tasks work with different objects using
457 the same id. For example same IPC id may refer to different objects
458 or same user id or pid may refer to different tasks when used in
459 different namespaces.
460
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461config UTS_NS
462 bool "UTS namespace"
463 depends on NAMESPACES
464 help
465 In this namespace tasks see different info provided with the
466 uname() system call
467
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468config IPC_NS
469 bool "IPC namespace"
470 depends on NAMESPACES && SYSVIPC
471 help
472 In this namespace tasks work with IPC ids which correspond to
473 different IPC objects in different namespaces
474
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475config USER_NS
476 bool "User namespace (EXPERIMENTAL)"
477 depends on NAMESPACES && EXPERIMENTAL
478 help
479 This allows containers, i.e. vservers, to use user namespaces
480 to provide different user info for different servers.
481 If unsure, say N.
482
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483config PID_NS
484 bool "PID Namespaces (EXPERIMENTAL)"
485 default n
486 depends on NAMESPACES && EXPERIMENTAL
487 help
488 Suport process id namespaces. This allows having multiple
489 process with the same pid as long as they are in different
490 pid namespaces. This is a building block of containers.
491
492 Unless you want to work with an experimental feature
493 say N here.
494
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495config BLK_DEV_INITRD
496 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
497 depends on BROKEN || !FRV
498 help
499 The initial RAM filesystem is a ramfs which is loaded by the
500 boot loader (loadlin or lilo) and that is mounted as root
501 before the normal boot procedure. It is typically used to
502 load modules needed to mount the "real" root file system,
503 etc. See <file:Documentation/initrd.txt> for details.
504
505 If RAM disk support (BLK_DEV_RAM) is also included, this
506 also enables initial RAM disk (initrd) support and adds
507 15 Kbytes (more on some other architectures) to the kernel size.
508
509 If unsure say Y.
510
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511if BLK_DEV_INITRD
512
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513source "usr/Kconfig"
514
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515endif
516
c45b4f1f 517config CC_OPTIMIZE_FOR_SIZE
96fffeb4 518 bool "Optimize for size"
c45b4f1f 519 default y
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520 help
521 Enabling this option will pass "-Os" instead of "-O2" to gcc
522 resulting in a smaller kernel.
523
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524 If unsure, say N.
525
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526config SYSCTL
527 bool
528
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529menuconfig EMBEDDED
530 bool "Configure standard kernel features (for small systems)"
531 help
532 This option allows certain base kernel options and settings
533 to be disabled or tweaked. This is for specialized
534 environments which can tolerate a "non-standard" kernel.
535 Only use this if you really know what you are doing.
536
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537config UID16
538 bool "Enable 16-bit UID system calls" if EMBEDDED
09337f50 539 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
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540 default y
541 help
542 This enables the legacy 16-bit UID syscall wrappers.
543
b89a8171 544config SYSCTL_SYSCALL
0847062a 545 bool "Sysctl syscall support" if EMBEDDED
13bb7e37 546 default y
b89a8171 547 select SYSCTL
ae81f9e3 548 ---help---
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549 sys_sysctl uses binary paths that have been found challenging
550 to properly maintain and use. The interface in /proc/sys
551 using paths with ascii names is now the primary path to this
552 information.
b89a8171 553
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554 Almost nothing using the binary sysctl interface so if you are
555 trying to save some space it is probably safe to disable this,
556 making your kernel marginally smaller.
b89a8171 557
13bb7e37 558 If unsure say Y here.
ae81f9e3 559
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560config SYSCTL_SYSCALL_CHECK
561 bool "Sysctl checks" if EMBEDDED
562 depends on SYSCTL_SYSCALL
563 default y
564 ---help---
565 sys_sysctl uses binary paths that have been found challenging
566 to properly maintain and use. This enables checks that help
567 you to keep things correct.
568
569 If unsure say Y here.
570
1da177e4 571config KALLSYMS
979c6a1e 572 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
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573 default y
574 help
575 Say Y here to let the kernel print out symbolic crash information and
576 symbolic stack backtraces. This increases the size of the kernel
577 somewhat, as all symbols have to be loaded into the kernel image.
578
579config KALLSYMS_ALL
580 bool "Include all symbols in kallsyms"
581 depends on DEBUG_KERNEL && KALLSYMS
582 help
583 Normally kallsyms only contains the symbols of functions, for nicer
584 OOPS messages. Some debuggers can use kallsyms for other
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585 symbols too: say Y here to include all symbols, if you need them
586 and you don't care about adding 300k to the size of your kernel.
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587
588 Say N.
589
590config KALLSYMS_EXTRA_PASS
591 bool "Do an extra kallsyms pass"
592 depends on KALLSYMS
593 help
594 If kallsyms is not working correctly, the build will fail with
595 inconsistent kallsyms data. If that occurs, log a bug report and
596 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
597 Always say N here unless you find a bug in kallsyms, which must be
598 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
599 you wait for kallsyms to be fixed.
600
d59745ce 601
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602config HOTPLUG
603 bool "Support for hot-pluggable devices" if EMBEDDED
604 default y
605 help
606 This option is provided for the case where no hotplug or uevent
607 capabilities is wanted by the kernel. You should only consider
608 disabling this option for embedded systems that do not use modules, a
609 dynamic /dev tree, or dynamic device discovery. Just say Y.
610
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611config PRINTK
612 default y
613 bool "Enable support for printk" if EMBEDDED
614 help
615 This option enables normal printk support. Removing it
616 eliminates most of the message strings from the kernel image
617 and makes the kernel more or less silent. As this makes it
618 very difficult to diagnose system problems, saying N here is
619 strongly discouraged.
620
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621config BUG
622 bool "BUG() support" if EMBEDDED
623 default y
624 help
625 Disabling this option eliminates support for BUG and WARN, reducing
626 the size of your kernel image and potentially quietly ignoring
627 numerous fatal conditions. You should only consider disabling this
628 option for embedded systems with no facilities for reporting errors.
629 Just say Y.
630
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631config ELF_CORE
632 default y
633 bool "Enable ELF core dumps" if EMBEDDED
634 help
635 Enable support for generating core dumps. Disabling saves about 4k.
636
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637config PCSPKR_PLATFORM
638 bool "Enable PC-Speaker support" if EMBEDDED
639 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
640 default y
641 help
642 This option allows to disable the internal PC-Speaker
643 support, saving some memory.
644
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645config COMPAT_BRK
646 bool "Disable heap randomization"
647 default y
648 help
649 Randomizing heap placement makes heap exploits harder, but it
650 also breaks ancient binaries (including anything libc5 based).
651 This option changes the bootup default to heap randomization
652 disabled, and can be overriden runtime by setting
653 /proc/sys/kernel/randomize_va_space to 2.
654
166124fd 655 On non-ancient distros (post-2000 ones) N is usually a safe choice.
32a93233 656
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657config BASE_FULL
658 default y
659 bool "Enable full-sized data structures for core" if EMBEDDED
660 help
661 Disabling this option reduces the size of miscellaneous core
662 kernel data structures. This saves memory on small machines,
663 but may reduce performance.
664
665config FUTEX
666 bool "Enable futex support" if EMBEDDED
667 default y
23f78d4a 668 select RT_MUTEXES
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669 help
670 Disabling this option will cause the kernel to be built without
671 support for "fast userspace mutexes". The resulting kernel may not
672 run glibc-based applications correctly.
673
5dc8bf81 674config ANON_INODES
448e3cee 675 bool
5dc8bf81 676
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677config EPOLL
678 bool "Enable eventpoll support" if EMBEDDED
679 default y
448e3cee 680 select ANON_INODES
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681 help
682 Disabling this option will cause the kernel to be built without
683 support for epoll family of system calls.
684
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685config SIGNALFD
686 bool "Enable signalfd() system call" if EMBEDDED
448e3cee 687 select ANON_INODES
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688 default y
689 help
690 Enable the signalfd() system call that allows to receive signals
691 on a file descriptor.
692
693 If unsure, say Y.
694
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695config TIMERFD
696 bool "Enable timerfd() system call" if EMBEDDED
448e3cee 697 select ANON_INODES
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698 default y
699 help
700 Enable the timerfd() system call that allows to receive timer
701 events on a file descriptor.
702
703 If unsure, say Y.
704
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705config EVENTFD
706 bool "Enable eventfd() system call" if EMBEDDED
448e3cee 707 select ANON_INODES
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708 default y
709 help
710 Enable the eventfd() system call that allows to receive both
711 kernel notification (ie. KAIO) or userspace notifications.
712
713 If unsure, say Y.
714
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715config SHMEM
716 bool "Use full shmem filesystem" if EMBEDDED
717 default y
718 depends on MMU
719 help
720 The shmem is an internal filesystem used to manage shared memory.
721 It is backed by swap and manages resource limits. It is also exported
722 to userspace as tmpfs if TMPFS is enabled. Disabling this
723 option replaces shmem and tmpfs with the much simpler ramfs code,
724 which may be appropriate on small systems without swap.
725
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726config VM_EVENT_COUNTERS
727 default y
728 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
729 help
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730 VM event counters are needed for event counts to be shown.
731 This option allows the disabling of the VM event counters
732 on EMBEDDED systems. /proc/vmstat will only show page counts
733 if VM event counters are disabled.
f8891e5e 734
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735config SLUB_DEBUG
736 default y
737 bool "Enable SLUB debugging support" if EMBEDDED
f6acb635 738 depends on SLUB && SYSFS
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739 help
740 SLUB has extensive debug support features. Disabling these can
741 result in significant savings in code size. This also disables
742 SLUB sysfs support. /sys/slab will not exist and there will be
743 no support for cache validation etc.
744
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745choice
746 prompt "Choose SLAB allocator"
a0acd820 747 default SLUB
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748 help
749 This option allows to select a slab allocator.
750
751config SLAB
752 bool "SLAB"
753 help
754 The regular slab allocator that is established and known to work
34013886 755 well in all environments. It organizes cache hot objects in
81819f0f 756 per cpu and per node queues. SLAB is the default choice for
34013886 757 a slab allocator.
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758
759config SLUB
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760 bool "SLUB (Unqueued Allocator)"
761 help
762 SLUB is a slab allocator that minimizes cache line usage
763 instead of managing queues of cached objects (SLAB approach).
764 Per cpu caching is realized using slabs of objects instead
765 of queues of objects. SLUB can use memory efficiently
34013886 766 and has enhanced diagnostics.
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767
768config SLOB
84a01c2f 769 depends on EMBEDDED
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770 bool "SLOB (Simple Allocator)"
771 help
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772 SLOB replaces the stock allocator with a drastically simpler
773 allocator. SLOB is generally more space efficient but
774 does not perform as well on large systems.
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775
776endchoice
777
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778config PROFILING
779 bool "Profiling support (EXPERIMENTAL)"
780 help
781 Say Y here to enable the extended profiling support mechanisms used
782 by profilers such as OProfile.
783
784config MARKERS
785 bool "Activate markers"
786 help
787 Place an empty function call at each marker site. Can be
788 dynamically changed for a probe function.
789
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790source "arch/Kconfig"
791
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792config PROC_PAGE_MONITOR
793 default y
794 depends on PROC_FS && MMU
795 bool "Enable /proc page monitoring" if EMBEDDED
796 help
797 Various /proc files exist to monitor process memory utilization:
798 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
799 /proc/kpagecount, and /proc/kpageflags. Disabling these
800 interfaces will reduce the size of the kernel by approximately 4kb.
801
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802endmenu # General setup
803
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804config SLABINFO
805 bool
806 depends on PROC_FS
0f389ec6 807 depends on SLAB || SLUB_DEBUG
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808 default y
809
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810config RT_MUTEXES
811 boolean
812 select PLIST
813
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814config TINY_SHMEM
815 default !SHMEM
816 bool
817
818config BASE_SMALL
819 int
820 default 0 if BASE_FULL
821 default 1 if !BASE_FULL
822
66da5733 823menuconfig MODULES
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824 bool "Enable loadable module support"
825 help
826 Kernel modules are small pieces of compiled code which can
827 be inserted in the running kernel, rather than being
828 permanently built into the kernel. You use the "modprobe"
829 tool to add (and sometimes remove) them. If you say Y here,
830 many parts of the kernel can be built as modules (by
831 answering M instead of Y where indicated): this is most
832 useful for infrequently used options which are not required
833 for booting. For more information, see the man pages for
834 modprobe, lsmod, modinfo, insmod and rmmod.
835
836 If you say Y here, you will need to run "make
837 modules_install" to put the modules under /lib/modules/
838 where modprobe can find them (you may need to be root to do
839 this).
840
841 If unsure, say Y.
842
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843config MODULE_FORCE_LOAD
844 bool "Forced module loading"
845 depends on MODULES
846 default n
847 help
848 This option allows loading of modules even if that would set the
849 'F' (forced) taint, due to lack of version info. Which is
850 usually a really bad idea.
851
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852config MODULE_UNLOAD
853 bool "Module unloading"
854 depends on MODULES
855 help
856 Without this option you will not be able to unload any
857 modules (note that some modules may not be unloadable
858 anyway), which makes your kernel slightly smaller and
859 simpler. If unsure, say Y.
860
861config MODULE_FORCE_UNLOAD
862 bool "Forced module unloading"
863 depends on MODULE_UNLOAD && EXPERIMENTAL
864 help
865 This option allows you to force a module to unload, even if the
866 kernel believes it is unsafe: the kernel will remove the module
867 without waiting for anyone to stop using it (using the -f option to
868 rmmod). This is mainly for kernel developers and desperate users.
869 If unsure, say N.
870
1da177e4 871config MODVERSIONS
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872 bool "Module versioning support"
873 depends on MODULES
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874 help
875 Usually, you have to use modules compiled with your kernel.
876 Saying Y here makes it sometimes possible to use modules
877 compiled for different kernels, by adding enough information
878 to the modules to (hopefully) spot any changes which would
879 make them incompatible with the kernel you are running. If
880 unsure, say N.
881
882config MODULE_SRCVERSION_ALL
883 bool "Source checksum for all modules"
884 depends on MODULES
885 help
886 Modules which contain a MODULE_VERSION get an extra "srcversion"
887 field inserted into their modinfo section, which contains a
888 sum of the source files which made it. This helps maintainers
889 see exactly which source was used to build a module (since
890 others sometimes change the module source without updating
891 the version). With this option, such a "srcversion" field
892 will be created for all modules. If unsure, say N.
893
894config KMOD
895 bool "Automatic kernel module loading"
896 depends on MODULES
897 help
898 Normally when you have selected some parts of the kernel to
899 be created as kernel modules, you must load them (using the
900 "modprobe" command) before you can use them. If you say Y
901 here, some parts of the kernel will be able to load modules
902 automatically: when a part of the kernel needs a module, it
903 runs modprobe with the appropriate arguments, thereby
904 loading the module if it is available. If unsure, say Y.
905
906config STOP_MACHINE
907 bool
908 default y
909 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
910 help
911 Need stop_machine() primitive.
3a65dfe8 912
3a65dfe8 913source "block/Kconfig"
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914
915config PREEMPT_NOTIFIERS
916 bool
e260be67 917
e260be67 918config CLASSIC_RCU
21bbb39c 919 def_bool !PREEMPT_RCU
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920 help
921 This option selects the classic RCU implementation that is
922 designed for best read-side performance on non-realtime
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923 systems. Classic RCU is the default. Note that the
924 PREEMPT_RCU symbol is used to select/deselect this option.