sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
[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41 drivers that have been replaced by something else, and/or are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"
de8d585a 327 default y
29f59db3 328 help
fb615581 329 This feature lets CPU scheduler recognize task groups and control CPU
9b5b7751 330 bandwidth allocation to such task groups.
29f59db3 331
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332config FAIR_GROUP_SCHED
333 bool "Group scheduling for SCHED_OTHER"
334 depends on GROUP_SCHED
335 default y
336
337config RT_GROUP_SCHED
338 bool "Group scheduling for SCHED_RR/FIFO"
339 depends on EXPERIMENTAL
340 depends on GROUP_SCHED
341 default n
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342 help
343 This feature lets you explicitly allocate real CPU bandwidth
344 to users or control groups (depending on the "Basis for grouping tasks"
345 setting below. If enabled, it will also make it impossible to
346 schedule realtime tasks for non-root users until you allocate
347 realtime bandwidth for them.
348 See Documentation/sched-rt-group.txt for more information.
052f1dc7 349
24e377a8 350choice
052f1dc7 351 depends on GROUP_SCHED
24e377a8 352 prompt "Basis for grouping tasks"
052f1dc7 353 default USER_SCHED
24e377a8 354
052f1dc7 355config USER_SCHED
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356 bool "user id"
357 help
358 This option will choose userid as the basis for grouping
359 tasks, thus providing equal CPU bandwidth to each user.
24e377a8 360
052f1dc7 361config CGROUP_SCHED
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362 bool "Control groups"
363 depends on CGROUPS
364 help
365 This option allows you to create arbitrary task groups
366 using the "cgroup" pseudo filesystem and control
367 the cpu bandwidth allocated to each such task group.
368 Refer to Documentation/cgroups.txt for more information
369 on "cgroup" pseudo filesystem.
370
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371endchoice
372
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373config CGROUP_CPUACCT
374 bool "Simple CPU accounting cgroup subsystem"
375 depends on CGROUPS
376 help
377 Provides a simple Resource Controller for monitoring the
378 total CPU consumed by the tasks in a cgroup
379
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380config RESOURCE_COUNTERS
381 bool "Resource counters"
382 help
383 This option enables controller independent resource accounting
384 infrastructure that works with cgroups
385 depends on CGROUPS
386
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387config MM_OWNER
388 bool
389
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390config CGROUP_MEM_RES_CTLR
391 bool "Memory Resource Controller for Control Groups"
392 depends on CGROUPS && RESOURCE_COUNTERS
cf475ad2 393 select MM_OWNER
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394 help
395 Provides a memory resource controller that manages both page cache and
396 RSS memory.
397
398 Note that setting this option increases fixed memory overhead
399 associated with each page of memory in the system by 4/8 bytes
400 and also increases cache misses because struct page on many 64bit
401 systems will not fit into a single cache line anymore.
402
403 Only enable when you're ok with these trade offs and really
404 sure you need the memory resource controller.
405
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406 This config option also selects MM_OWNER config option, which
407 could in turn add some fork/exit overhead.
408
88a22c98 409config SYSFS_DEPRECATED
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410 bool
411
412config SYSFS_DEPRECATED_V2
88a22c98 413 bool "Create deprecated sysfs files"
9148fe87 414 depends on SYSFS
88a22c98 415 default y
d47846c5 416 select SYSFS_DEPRECATED
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417 help
418 This option creates deprecated symlinks such as the
419 "device"-link, the <subsystem>:<name>-link, and the
420 "bus"-link. It may also add deprecated key in the
421 uevent environment.
422 None of these features or values should be used today, as
423 they export driver core implementation details to userspace
424 or export properties which can't be kept stable across kernel
425 releases.
426
427 If enabled, this option will also move any device structures
3dde6ad8 428 that belong to a class, back into the /sys/class hierarchy, in
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429 order to support older versions of udev and some userspace
430 programs.
88a22c98 431
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432 If you are using a distro with the most recent userspace
433 packages, it should be safe to say N here.
88a22c98 434
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435config PROC_PID_CPUSET
436 bool "Include legacy /proc/<pid>/cpuset file"
437 depends on CPUSETS
438 default y
439
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440config RELAY
441 bool "Kernel->user space relay support (formerly relayfs)"
442 help
443 This option enables support for relay interface support in
444 certain file systems (such as debugfs).
445 It is designed to provide an efficient mechanism for tools and
446 facilities to relay large amounts of data from kernel space to
447 user space.
448
449 If unsure, say N.
450
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451config NAMESPACES
452 bool "Namespaces support" if EMBEDDED
453 default !EMBEDDED
454 help
455 Provides the way to make tasks work with different objects using
456 the same id. For example same IPC id may refer to different objects
457 or same user id or pid may refer to different tasks when used in
458 different namespaces.
459
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460config UTS_NS
461 bool "UTS namespace"
462 depends on NAMESPACES
463 help
464 In this namespace tasks see different info provided with the
465 uname() system call
466
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467config IPC_NS
468 bool "IPC namespace"
469 depends on NAMESPACES && SYSVIPC
470 help
471 In this namespace tasks work with IPC ids which correspond to
472 different IPC objects in different namespaces
473
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474config USER_NS
475 bool "User namespace (EXPERIMENTAL)"
476 depends on NAMESPACES && EXPERIMENTAL
477 help
478 This allows containers, i.e. vservers, to use user namespaces
479 to provide different user info for different servers.
480 If unsure, say N.
481
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482config PID_NS
483 bool "PID Namespaces (EXPERIMENTAL)"
484 default n
485 depends on NAMESPACES && EXPERIMENTAL
486 help
487 Suport process id namespaces. This allows having multiple
488 process with the same pid as long as they are in different
489 pid namespaces. This is a building block of containers.
490
491 Unless you want to work with an experimental feature
492 say N here.
493
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494config BLK_DEV_INITRD
495 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
496 depends on BROKEN || !FRV
497 help
498 The initial RAM filesystem is a ramfs which is loaded by the
499 boot loader (loadlin or lilo) and that is mounted as root
500 before the normal boot procedure. It is typically used to
501 load modules needed to mount the "real" root file system,
502 etc. See <file:Documentation/initrd.txt> for details.
503
504 If RAM disk support (BLK_DEV_RAM) is also included, this
505 also enables initial RAM disk (initrd) support and adds
506 15 Kbytes (more on some other architectures) to the kernel size.
507
508 If unsure say Y.
509
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510if BLK_DEV_INITRD
511
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512source "usr/Kconfig"
513
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514endif
515
c45b4f1f 516config CC_OPTIMIZE_FOR_SIZE
96fffeb4 517 bool "Optimize for size"
c45b4f1f 518 default y
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519 help
520 Enabling this option will pass "-Os" instead of "-O2" to gcc
521 resulting in a smaller kernel.
522
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523 If unsure, say N.
524
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525config SYSCTL
526 bool
527
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528menuconfig EMBEDDED
529 bool "Configure standard kernel features (for small systems)"
530 help
531 This option allows certain base kernel options and settings
532 to be disabled or tweaked. This is for specialized
533 environments which can tolerate a "non-standard" kernel.
534 Only use this if you really know what you are doing.
535
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536config UID16
537 bool "Enable 16-bit UID system calls" if EMBEDDED
09337f50 538 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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539 default y
540 help
541 This enables the legacy 16-bit UID syscall wrappers.
542
b89a8171 543config SYSCTL_SYSCALL
0847062a 544 bool "Sysctl syscall support" if EMBEDDED
13bb7e37 545 default y
b89a8171 546 select SYSCTL
ae81f9e3 547 ---help---
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548 sys_sysctl uses binary paths that have been found challenging
549 to properly maintain and use. The interface in /proc/sys
550 using paths with ascii names is now the primary path to this
551 information.
b89a8171 552
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553 Almost nothing using the binary sysctl interface so if you are
554 trying to save some space it is probably safe to disable this,
555 making your kernel marginally smaller.
b89a8171 556
13bb7e37 557 If unsure say Y here.
ae81f9e3 558
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559config SYSCTL_SYSCALL_CHECK
560 bool "Sysctl checks" if EMBEDDED
561 depends on SYSCTL_SYSCALL
562 default y
563 ---help---
564 sys_sysctl uses binary paths that have been found challenging
565 to properly maintain and use. This enables checks that help
566 you to keep things correct.
567
568 If unsure say Y here.
569
1da177e4 570config KALLSYMS
979c6a1e 571 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
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572 default y
573 help
574 Say Y here to let the kernel print out symbolic crash information and
575 symbolic stack backtraces. This increases the size of the kernel
576 somewhat, as all symbols have to be loaded into the kernel image.
577
578config KALLSYMS_ALL
579 bool "Include all symbols in kallsyms"
580 depends on DEBUG_KERNEL && KALLSYMS
581 help
582 Normally kallsyms only contains the symbols of functions, for nicer
583 OOPS messages. Some debuggers can use kallsyms for other
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584 symbols too: say Y here to include all symbols, if you need them
585 and you don't care about adding 300k to the size of your kernel.
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586
587 Say N.
588
589config KALLSYMS_EXTRA_PASS
590 bool "Do an extra kallsyms pass"
591 depends on KALLSYMS
592 help
593 If kallsyms is not working correctly, the build will fail with
594 inconsistent kallsyms data. If that occurs, log a bug report and
595 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
596 Always say N here unless you find a bug in kallsyms, which must be
597 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
598 you wait for kallsyms to be fixed.
599
d59745ce 600
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601config HOTPLUG
602 bool "Support for hot-pluggable devices" if EMBEDDED
603 default y
604 help
605 This option is provided for the case where no hotplug or uevent
606 capabilities is wanted by the kernel. You should only consider
607 disabling this option for embedded systems that do not use modules, a
608 dynamic /dev tree, or dynamic device discovery. Just say Y.
609
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610config PRINTK
611 default y
612 bool "Enable support for printk" if EMBEDDED
613 help
614 This option enables normal printk support. Removing it
615 eliminates most of the message strings from the kernel image
616 and makes the kernel more or less silent. As this makes it
617 very difficult to diagnose system problems, saying N here is
618 strongly discouraged.
619
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620config BUG
621 bool "BUG() support" if EMBEDDED
622 default y
623 help
624 Disabling this option eliminates support for BUG and WARN, reducing
625 the size of your kernel image and potentially quietly ignoring
626 numerous fatal conditions. You should only consider disabling this
627 option for embedded systems with no facilities for reporting errors.
628 Just say Y.
629
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630config ELF_CORE
631 default y
632 bool "Enable ELF core dumps" if EMBEDDED
633 help
634 Enable support for generating core dumps. Disabling saves about 4k.
635
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636config COMPAT_BRK
637 bool "Disable heap randomization"
638 default y
639 help
640 Randomizing heap placement makes heap exploits harder, but it
641 also breaks ancient binaries (including anything libc5 based).
642 This option changes the bootup default to heap randomization
643 disabled, and can be overriden runtime by setting
644 /proc/sys/kernel/randomize_va_space to 2.
645
166124fd 646 On non-ancient distros (post-2000 ones) N is usually a safe choice.
32a93233 647
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648config BASE_FULL
649 default y
650 bool "Enable full-sized data structures for core" if EMBEDDED
651 help
652 Disabling this option reduces the size of miscellaneous core
653 kernel data structures. This saves memory on small machines,
654 but may reduce performance.
655
656config FUTEX
657 bool "Enable futex support" if EMBEDDED
658 default y
23f78d4a 659 select RT_MUTEXES
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660 help
661 Disabling this option will cause the kernel to be built without
662 support for "fast userspace mutexes". The resulting kernel may not
663 run glibc-based applications correctly.
664
5dc8bf81 665config ANON_INODES
448e3cee 666 bool
5dc8bf81 667
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668config EPOLL
669 bool "Enable eventpoll support" if EMBEDDED
670 default y
448e3cee 671 select ANON_INODES
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672 help
673 Disabling this option will cause the kernel to be built without
674 support for epoll family of system calls.
675
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676config SIGNALFD
677 bool "Enable signalfd() system call" if EMBEDDED
448e3cee 678 select ANON_INODES
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679 default y
680 help
681 Enable the signalfd() system call that allows to receive signals
682 on a file descriptor.
683
684 If unsure, say Y.
685
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686config TIMERFD
687 bool "Enable timerfd() system call" if EMBEDDED
448e3cee 688 select ANON_INODES
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689 default y
690 help
691 Enable the timerfd() system call that allows to receive timer
692 events on a file descriptor.
693
694 If unsure, say Y.
695
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696config EVENTFD
697 bool "Enable eventfd() system call" if EMBEDDED
448e3cee 698 select ANON_INODES
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699 default y
700 help
701 Enable the eventfd() system call that allows to receive both
702 kernel notification (ie. KAIO) or userspace notifications.
703
704 If unsure, say Y.
705
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706config SHMEM
707 bool "Use full shmem filesystem" if EMBEDDED
708 default y
709 depends on MMU
710 help
711 The shmem is an internal filesystem used to manage shared memory.
712 It is backed by swap and manages resource limits. It is also exported
713 to userspace as tmpfs if TMPFS is enabled. Disabling this
714 option replaces shmem and tmpfs with the much simpler ramfs code,
715 which may be appropriate on small systems without swap.
716
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717config VM_EVENT_COUNTERS
718 default y
719 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
720 help
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721 VM event counters are needed for event counts to be shown.
722 This option allows the disabling of the VM event counters
723 on EMBEDDED systems. /proc/vmstat will only show page counts
724 if VM event counters are disabled.
f8891e5e 725
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726config SLUB_DEBUG
727 default y
728 bool "Enable SLUB debugging support" if EMBEDDED
f6acb635 729 depends on SLUB && SYSFS
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730 help
731 SLUB has extensive debug support features. Disabling these can
732 result in significant savings in code size. This also disables
733 SLUB sysfs support. /sys/slab will not exist and there will be
734 no support for cache validation etc.
735
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736choice
737 prompt "Choose SLAB allocator"
a0acd820 738 default SLUB
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739 help
740 This option allows to select a slab allocator.
741
742config SLAB
743 bool "SLAB"
744 help
745 The regular slab allocator that is established and known to work
34013886 746 well in all environments. It organizes cache hot objects in
81819f0f 747 per cpu and per node queues. SLAB is the default choice for
34013886 748 a slab allocator.
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749
750config SLUB
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751 bool "SLUB (Unqueued Allocator)"
752 help
753 SLUB is a slab allocator that minimizes cache line usage
754 instead of managing queues of cached objects (SLAB approach).
755 Per cpu caching is realized using slabs of objects instead
756 of queues of objects. SLUB can use memory efficiently
34013886 757 and has enhanced diagnostics.
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758
759config SLOB
84a01c2f 760 depends on EMBEDDED
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761 bool "SLOB (Simple Allocator)"
762 help
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763 SLOB replaces the stock allocator with a drastically simpler
764 allocator. SLOB is generally more space efficient but
765 does not perform as well on large systems.
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766
767endchoice
768
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769config PROFILING
770 bool "Profiling support (EXPERIMENTAL)"
771 help
772 Say Y here to enable the extended profiling support mechanisms used
773 by profilers such as OProfile.
774
775config MARKERS
776 bool "Activate markers"
777 help
778 Place an empty function call at each marker site. Can be
779 dynamically changed for a probe function.
780
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781source "arch/Kconfig"
782
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783config PROC_PAGE_MONITOR
784 default y
785 depends on PROC_FS && MMU
786 bool "Enable /proc page monitoring" if EMBEDDED
787 help
788 Various /proc files exist to monitor process memory utilization:
789 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
790 /proc/kpagecount, and /proc/kpageflags. Disabling these
791 interfaces will reduce the size of the kernel by approximately 4kb.
792
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793endmenu # General setup
794
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795config SLABINFO
796 bool
797 depends on PROC_FS
0f389ec6 798 depends on SLAB || SLUB_DEBUG
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799 default y
800
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801config RT_MUTEXES
802 boolean
803 select PLIST
804
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805config TINY_SHMEM
806 default !SHMEM
807 bool
808
809config BASE_SMALL
810 int
811 default 0 if BASE_FULL
812 default 1 if !BASE_FULL
813
66da5733 814menuconfig MODULES
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815 bool "Enable loadable module support"
816 help
817 Kernel modules are small pieces of compiled code which can
818 be inserted in the running kernel, rather than being
819 permanently built into the kernel. You use the "modprobe"
820 tool to add (and sometimes remove) them. If you say Y here,
821 many parts of the kernel can be built as modules (by
822 answering M instead of Y where indicated): this is most
823 useful for infrequently used options which are not required
824 for booting. For more information, see the man pages for
825 modprobe, lsmod, modinfo, insmod and rmmod.
826
827 If you say Y here, you will need to run "make
828 modules_install" to put the modules under /lib/modules/
829 where modprobe can find them (you may need to be root to do
830 this).
831
832 If unsure, say Y.
833
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834config MODULE_FORCE_LOAD
835 bool "Forced module loading"
836 depends on MODULES
837 default n
838 help
839 This option allows loading of modules even if that would set the
840 'F' (forced) taint, due to lack of version info. Which is
841 usually a really bad idea.
842
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843config MODULE_UNLOAD
844 bool "Module unloading"
845 depends on MODULES
846 help
847 Without this option you will not be able to unload any
848 modules (note that some modules may not be unloadable
849 anyway), which makes your kernel slightly smaller and
850 simpler. If unsure, say Y.
851
852config MODULE_FORCE_UNLOAD
853 bool "Forced module unloading"
854 depends on MODULE_UNLOAD && EXPERIMENTAL
855 help
856 This option allows you to force a module to unload, even if the
857 kernel believes it is unsafe: the kernel will remove the module
858 without waiting for anyone to stop using it (using the -f option to
859 rmmod). This is mainly for kernel developers and desperate users.
860 If unsure, say N.
861
1da177e4 862config MODVERSIONS
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863 bool "Module versioning support"
864 depends on MODULES
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865 help
866 Usually, you have to use modules compiled with your kernel.
867 Saying Y here makes it sometimes possible to use modules
868 compiled for different kernels, by adding enough information
869 to the modules to (hopefully) spot any changes which would
870 make them incompatible with the kernel you are running. If
871 unsure, say N.
872
873config MODULE_SRCVERSION_ALL
874 bool "Source checksum for all modules"
875 depends on MODULES
876 help
877 Modules which contain a MODULE_VERSION get an extra "srcversion"
878 field inserted into their modinfo section, which contains a
879 sum of the source files which made it. This helps maintainers
880 see exactly which source was used to build a module (since
881 others sometimes change the module source without updating
882 the version). With this option, such a "srcversion" field
883 will be created for all modules. If unsure, say N.
884
885config KMOD
886 bool "Automatic kernel module loading"
887 depends on MODULES
888 help
889 Normally when you have selected some parts of the kernel to
890 be created as kernel modules, you must load them (using the
891 "modprobe" command) before you can use them. If you say Y
892 here, some parts of the kernel will be able to load modules
893 automatically: when a part of the kernel needs a module, it
894 runs modprobe with the appropriate arguments, thereby
895 loading the module if it is available. If unsure, say Y.
896
897config STOP_MACHINE
898 bool
899 default y
900 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
901 help
902 Need stop_machine() primitive.
3a65dfe8 903
3a65dfe8 904source "block/Kconfig"
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905
906config PREEMPT_NOTIFIERS
907 bool
e260be67 908
e260be67 909config CLASSIC_RCU
21bbb39c 910 def_bool !PREEMPT_RCU
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911 help
912 This option selects the classic RCU implementation that is
913 designed for best read-side performance on non-realtime
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914 systems. Classic RCU is the default. Note that the
915 PREEMPT_RCU symbol is used to select/deselect this option.