Kconfig 22 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670
  1. config DEFCONFIG_LIST
  2. string
  3. depends on !UML
  4. option defconfig_list
  5. default "/lib/modules/$UNAME_RELEASE/.config"
  6. default "/etc/kernel-config"
  7. default "/boot/config-$UNAME_RELEASE"
  8. default "arch/$ARCH/defconfig"
  9. menu "General setup"
  10. config EXPERIMENTAL
  11. bool "Prompt for development and/or incomplete code/drivers"
  12. ---help---
  13. Some of the various things that Linux supports (such as network
  14. drivers, file systems, network protocols, etc.) can be in a state
  15. of development where the functionality, stability, or the level of
  16. testing is not yet high enough for general use. This is usually
  17. known as the "alpha-test" phase among developers. If a feature is
  18. currently in alpha-test, then the developers usually discourage
  19. uninformed widespread use of this feature by the general public to
  20. avoid "Why doesn't this work?" type mail messages. However, active
  21. testing and use of these systems is welcomed. Just be aware that it
  22. may not meet the normal level of reliability or it may fail to work
  23. in some special cases. Detailed bug reports from people familiar
  24. with the kernel internals are usually welcomed by the developers
  25. (before submitting bug reports, please read the documents
  26. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  27. <file:Documentation/BUG-HUNTING>, and
  28. <file:Documentation/oops-tracing.txt> in the kernel source).
  29. This option will also make obsoleted drivers available. These are
  30. drivers that have been replaced by something else, and/or are
  31. scheduled to be removed in a future kernel release.
  32. Unless you intend to help test and develop a feature or driver that
  33. falls into this category, or you have a situation that requires
  34. using these features, you should probably say N here, which will
  35. cause the configurator to present you with fewer choices. If
  36. you say Y here, you will be offered the choice of using features or
  37. drivers that are currently considered to be in the alpha-test phase.
  38. config BROKEN
  39. bool
  40. config BROKEN_ON_SMP
  41. bool
  42. depends on BROKEN || !SMP
  43. default y
  44. config LOCK_KERNEL
  45. bool
  46. depends on SMP || PREEMPT
  47. default y
  48. config INIT_ENV_ARG_LIMIT
  49. int
  50. default 32 if !UML
  51. default 128 if UML
  52. help
  53. Maximum of each of the number of arguments and environment
  54. variables passed to init from the kernel command line.
  55. config LOCALVERSION
  56. string "Local version - append to kernel release"
  57. help
  58. Append an extra string to the end of your kernel version.
  59. This will show up when you type uname, for example.
  60. The string you set here will be appended after the contents of
  61. any files with a filename matching localversion* in your
  62. object and source tree, in that order. Your total string can
  63. be a maximum of 64 characters.
  64. config LOCALVERSION_AUTO
  65. bool "Automatically append version information to the version string"
  66. default y
  67. help
  68. This will try to automatically determine if the current tree is a
  69. release tree by looking for git tags that belong to the current
  70. top of tree revision.
  71. A string of the format -gxxxxxxxx will be added to the localversion
  72. if a git-based tree is found. The string generated by this will be
  73. appended after any matching localversion* files, and after the value
  74. set in CONFIG_LOCALVERSION.
  75. (The actual string used here is the first eight characters produced
  76. by running the command:
  77. $ git rev-parse --verify HEAD
  78. which is done within the script "scripts/setlocalversion".)
  79. config SWAP
  80. bool "Support for paging of anonymous memory (swap)"
  81. depends on MMU && BLOCK
  82. default y
  83. help
  84. This option allows you to choose whether you want to have support
  85. for so called swap devices or swap files in your kernel that are
  86. used to provide more virtual memory than the actual RAM present
  87. in your computer. If unsure say Y.
  88. config SYSVIPC
  89. bool "System V IPC"
  90. ---help---
  91. Inter Process Communication is a suite of library functions and
  92. system calls which let processes (running programs) synchronize and
  93. exchange information. It is generally considered to be a good thing,
  94. and some programs won't run unless you say Y here. In particular, if
  95. you want to run the DOS emulator dosemu under Linux (read the
  96. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  97. you'll need to say Y here.
  98. You can find documentation about IPC with "info ipc" and also in
  99. section 6.4 of the Linux Programmer's Guide, available from
  100. <http://www.tldp.org/guides.html>.
  101. config SYSVIPC_SYSCTL
  102. bool
  103. depends on SYSVIPC
  104. depends on SYSCTL
  105. default y
  106. config POSIX_MQUEUE
  107. bool "POSIX Message Queues"
  108. depends on NET && EXPERIMENTAL
  109. ---help---
  110. POSIX variant of message queues is a part of IPC. In POSIX message
  111. queues every message has a priority which decides about succession
  112. of receiving it by a process. If you want to compile and run
  113. programs written e.g. for Solaris with use of its POSIX message
  114. queues (functions mq_*) say Y here.
  115. POSIX message queues are visible as a filesystem called 'mqueue'
  116. and can be mounted somewhere if you want to do filesystem
  117. operations on message queues.
  118. If unsure, say Y.
  119. config BSD_PROCESS_ACCT
  120. bool "BSD Process Accounting"
  121. help
  122. If you say Y here, a user level program will be able to instruct the
  123. kernel (via a special system call) to write process accounting
  124. information to a file: whenever a process exits, information about
  125. that process will be appended to the file by the kernel. The
  126. information includes things such as creation time, owning user,
  127. command name, memory usage, controlling terminal etc. (the complete
  128. list is in the struct acct in <file:include/linux/acct.h>). It is
  129. up to the user level program to do useful things with this
  130. information. This is generally a good idea, so say Y.
  131. config BSD_PROCESS_ACCT_V3
  132. bool "BSD Process Accounting version 3 file format"
  133. depends on BSD_PROCESS_ACCT
  134. default n
  135. help
  136. If you say Y here, the process accounting information is written
  137. in a new file format that also logs the process IDs of each
  138. process and it's parent. Note that this file format is incompatible
  139. with previous v0/v1/v2 file formats, so you will need updated tools
  140. for processing it. A preliminary version of these tools is available
  141. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  142. config TASKSTATS
  143. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  144. depends on NET
  145. default n
  146. help
  147. Export selected statistics for tasks/processes through the
  148. generic netlink interface. Unlike BSD process accounting, the
  149. statistics are available during the lifetime of tasks/processes as
  150. responses to commands. Like BSD accounting, they are sent to user
  151. space on task exit.
  152. Say N if unsure.
  153. config TASK_DELAY_ACCT
  154. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  155. depends on TASKSTATS
  156. help
  157. Collect information on time spent by a task waiting for system
  158. resources like cpu, synchronous block I/O completion and swapping
  159. in pages. Such statistics can help in setting a task's priorities
  160. relative to other tasks for cpu, io, rss limits etc.
  161. Say N if unsure.
  162. config TASK_XACCT
  163. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  164. depends on TASKSTATS
  165. help
  166. Collect extended task accounting data and send the data
  167. to userland for processing over the taskstats interface.
  168. Say N if unsure.
  169. config TASK_IO_ACCOUNTING
  170. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  171. depends on TASK_XACCT
  172. help
  173. Collect information on the number of bytes of storage I/O which this
  174. task has caused.
  175. Say N if unsure.
  176. config USER_NS
  177. bool "User Namespaces (EXPERIMENTAL)"
  178. default n
  179. depends on EXPERIMENTAL
  180. help
  181. Support user namespaces. This allows containers, i.e.
  182. vservers, to use user namespaces to provide different
  183. user info for different servers. If unsure, say N.
  184. config AUDIT
  185. bool "Auditing support"
  186. depends on NET
  187. help
  188. Enable auditing infrastructure that can be used with another
  189. kernel subsystem, such as SELinux (which requires this for
  190. logging of avc messages output). Does not do system-call
  191. auditing without CONFIG_AUDITSYSCALL.
  192. config AUDITSYSCALL
  193. bool "Enable system-call auditing support"
  194. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  195. default y if SECURITY_SELINUX
  196. help
  197. Enable low-overhead system-call auditing infrastructure that
  198. can be used independently or with another kernel subsystem,
  199. such as SELinux. To use audit's filesystem watch feature, please
  200. ensure that INOTIFY is configured.
  201. config IKCONFIG
  202. tristate "Kernel .config support"
  203. ---help---
  204. This option enables the complete Linux kernel ".config" file
  205. contents to be saved in the kernel. It provides documentation
  206. of which kernel options are used in a running kernel or in an
  207. on-disk kernel. This information can be extracted from the kernel
  208. image file with the script scripts/extract-ikconfig and used as
  209. input to rebuild the current kernel or to build another kernel.
  210. It can also be extracted from a running kernel by reading
  211. /proc/config.gz if enabled (below).
  212. config IKCONFIG_PROC
  213. bool "Enable access to .config through /proc/config.gz"
  214. depends on IKCONFIG && PROC_FS
  215. ---help---
  216. This option enables access to the kernel configuration file
  217. through /proc/config.gz.
  218. config LOG_BUF_SHIFT
  219. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  220. range 12 21
  221. default 17 if S390 || LOCKDEP
  222. default 16 if X86_NUMAQ || IA64
  223. default 15 if SMP
  224. default 14
  225. help
  226. Select kernel log buffer size as a power of 2.
  227. Defaults and Examples:
  228. 17 => 128 KB for S/390
  229. 16 => 64 KB for x86 NUMAQ or IA-64
  230. 15 => 32 KB for SMP
  231. 14 => 16 KB for uniprocessor
  232. 13 => 8 KB
  233. 12 => 4 KB
  234. config CPUSETS
  235. bool "Cpuset support"
  236. depends on SMP
  237. help
  238. This option will let you create and manage CPUSETs which
  239. allow dynamically partitioning a system into sets of CPUs and
  240. Memory Nodes and assigning tasks to run only within those sets.
  241. This is primarily useful on large SMP or NUMA systems.
  242. Say N if unsure.
  243. config SYSFS_DEPRECATED
  244. bool "Create deprecated sysfs files"
  245. default y
  246. help
  247. This option creates deprecated symlinks such as the
  248. "device"-link, the <subsystem>:<name>-link, and the
  249. "bus"-link. It may also add deprecated key in the
  250. uevent environment.
  251. None of these features or values should be used today, as
  252. they export driver core implementation details to userspace
  253. or export properties which can't be kept stable across kernel
  254. releases.
  255. If enabled, this option will also move any device structures
  256. that belong to a class, back into the /sys/class hierarchy, in
  257. order to support older versions of udev.
  258. If you are using a distro that was released in 2006 or later,
  259. it should be safe to say N here.
  260. config RELAY
  261. bool "Kernel->user space relay support (formerly relayfs)"
  262. help
  263. This option enables support for relay interface support in
  264. certain file systems (such as debugfs).
  265. It is designed to provide an efficient mechanism for tools and
  266. facilities to relay large amounts of data from kernel space to
  267. user space.
  268. If unsure, say N.
  269. config BLK_DEV_INITRD
  270. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  271. depends on BROKEN || !FRV
  272. help
  273. The initial RAM filesystem is a ramfs which is loaded by the
  274. boot loader (loadlin or lilo) and that is mounted as root
  275. before the normal boot procedure. It is typically used to
  276. load modules needed to mount the "real" root file system,
  277. etc. See <file:Documentation/initrd.txt> for details.
  278. If RAM disk support (BLK_DEV_RAM) is also included, this
  279. also enables initial RAM disk (initrd) support and adds
  280. 15 Kbytes (more on some other architectures) to the kernel size.
  281. If unsure say Y.
  282. if BLK_DEV_INITRD
  283. source "usr/Kconfig"
  284. endif
  285. config CC_OPTIMIZE_FOR_SIZE
  286. bool "Optimize for size (Look out for broken compilers!)"
  287. default y
  288. depends on ARM || H8300 || SUPERH || EXPERIMENTAL
  289. help
  290. Enabling this option will pass "-Os" instead of "-O2" to gcc
  291. resulting in a smaller kernel.
  292. WARNING: some versions of gcc may generate incorrect code with this
  293. option. If problems are observed, a gcc upgrade may be needed.
  294. If unsure, say N.
  295. config SYSCTL
  296. bool
  297. menuconfig EMBEDDED
  298. bool "Configure standard kernel features (for small systems)"
  299. help
  300. This option allows certain base kernel options and settings
  301. to be disabled or tweaked. This is for specialized
  302. environments which can tolerate a "non-standard" kernel.
  303. Only use this if you really know what you are doing.
  304. config UID16
  305. bool "Enable 16-bit UID system calls" if EMBEDDED
  306. depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  307. default y
  308. help
  309. This enables the legacy 16-bit UID syscall wrappers.
  310. config SYSCTL_SYSCALL
  311. bool "Sysctl syscall support" if EMBEDDED
  312. default y
  313. select SYSCTL
  314. ---help---
  315. sys_sysctl uses binary paths that have been found challenging
  316. to properly maintain and use. The interface in /proc/sys
  317. using paths with ascii names is now the primary path to this
  318. information.
  319. Almost nothing using the binary sysctl interface so if you are
  320. trying to save some space it is probably safe to disable this,
  321. making your kernel marginally smaller.
  322. If unsure say Y here.
  323. config KALLSYMS
  324. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  325. default y
  326. help
  327. Say Y here to let the kernel print out symbolic crash information and
  328. symbolic stack backtraces. This increases the size of the kernel
  329. somewhat, as all symbols have to be loaded into the kernel image.
  330. config KALLSYMS_ALL
  331. bool "Include all symbols in kallsyms"
  332. depends on DEBUG_KERNEL && KALLSYMS
  333. help
  334. Normally kallsyms only contains the symbols of functions, for nicer
  335. OOPS messages. Some debuggers can use kallsyms for other
  336. symbols too: say Y here to include all symbols, if you need them
  337. and you don't care about adding 300k to the size of your kernel.
  338. Say N.
  339. config KALLSYMS_EXTRA_PASS
  340. bool "Do an extra kallsyms pass"
  341. depends on KALLSYMS
  342. help
  343. If kallsyms is not working correctly, the build will fail with
  344. inconsistent kallsyms data. If that occurs, log a bug report and
  345. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  346. Always say N here unless you find a bug in kallsyms, which must be
  347. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  348. you wait for kallsyms to be fixed.
  349. config HOTPLUG
  350. bool "Support for hot-pluggable devices" if EMBEDDED
  351. default y
  352. help
  353. This option is provided for the case where no hotplug or uevent
  354. capabilities is wanted by the kernel. You should only consider
  355. disabling this option for embedded systems that do not use modules, a
  356. dynamic /dev tree, or dynamic device discovery. Just say Y.
  357. config PRINTK
  358. default y
  359. bool "Enable support for printk" if EMBEDDED
  360. help
  361. This option enables normal printk support. Removing it
  362. eliminates most of the message strings from the kernel image
  363. and makes the kernel more or less silent. As this makes it
  364. very difficult to diagnose system problems, saying N here is
  365. strongly discouraged.
  366. config BUG
  367. bool "BUG() support" if EMBEDDED
  368. default y
  369. help
  370. Disabling this option eliminates support for BUG and WARN, reducing
  371. the size of your kernel image and potentially quietly ignoring
  372. numerous fatal conditions. You should only consider disabling this
  373. option for embedded systems with no facilities for reporting errors.
  374. Just say Y.
  375. config ELF_CORE
  376. default y
  377. bool "Enable ELF core dumps" if EMBEDDED
  378. help
  379. Enable support for generating core dumps. Disabling saves about 4k.
  380. config BASE_FULL
  381. default y
  382. bool "Enable full-sized data structures for core" if EMBEDDED
  383. help
  384. Disabling this option reduces the size of miscellaneous core
  385. kernel data structures. This saves memory on small machines,
  386. but may reduce performance.
  387. config FUTEX
  388. bool "Enable futex support" if EMBEDDED
  389. default y
  390. select RT_MUTEXES
  391. help
  392. Disabling this option will cause the kernel to be built without
  393. support for "fast userspace mutexes". The resulting kernel may not
  394. run glibc-based applications correctly.
  395. config ANON_INODES
  396. bool
  397. config EPOLL
  398. bool "Enable eventpoll support" if EMBEDDED
  399. default y
  400. select ANON_INODES
  401. help
  402. Disabling this option will cause the kernel to be built without
  403. support for epoll family of system calls.
  404. config SIGNALFD
  405. bool "Enable signalfd() system call" if EMBEDDED
  406. select ANON_INODES
  407. default y
  408. help
  409. Enable the signalfd() system call that allows to receive signals
  410. on a file descriptor.
  411. If unsure, say Y.
  412. config TIMERFD
  413. bool "Enable timerfd() system call" if EMBEDDED
  414. select ANON_INODES
  415. depends on BROKEN
  416. default y
  417. help
  418. Enable the timerfd() system call that allows to receive timer
  419. events on a file descriptor.
  420. If unsure, say Y.
  421. config EVENTFD
  422. bool "Enable eventfd() system call" if EMBEDDED
  423. select ANON_INODES
  424. default y
  425. help
  426. Enable the eventfd() system call that allows to receive both
  427. kernel notification (ie. KAIO) or userspace notifications.
  428. If unsure, say Y.
  429. config SHMEM
  430. bool "Use full shmem filesystem" if EMBEDDED
  431. default y
  432. depends on MMU
  433. help
  434. The shmem is an internal filesystem used to manage shared memory.
  435. It is backed by swap and manages resource limits. It is also exported
  436. to userspace as tmpfs if TMPFS is enabled. Disabling this
  437. option replaces shmem and tmpfs with the much simpler ramfs code,
  438. which may be appropriate on small systems without swap.
  439. config VM_EVENT_COUNTERS
  440. default y
  441. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  442. help
  443. VM event counters are needed for event counts to be shown.
  444. This option allows the disabling of the VM event counters
  445. on EMBEDDED systems. /proc/vmstat will only show page counts
  446. if VM event counters are disabled.
  447. config SLUB_DEBUG
  448. default y
  449. bool "Enable SLUB debugging support" if EMBEDDED
  450. depends on SLUB
  451. help
  452. SLUB has extensive debug support features. Disabling these can
  453. result in significant savings in code size. This also disables
  454. SLUB sysfs support. /sys/slab will not exist and there will be
  455. no support for cache validation etc.
  456. choice
  457. prompt "Choose SLAB allocator"
  458. default SLUB
  459. help
  460. This option allows to select a slab allocator.
  461. config SLAB
  462. bool "SLAB"
  463. help
  464. The regular slab allocator that is established and known to work
  465. well in all environments. It organizes cache hot objects in
  466. per cpu and per node queues. SLAB is the default choice for
  467. a slab allocator.
  468. config SLUB
  469. bool "SLUB (Unqueued Allocator)"
  470. help
  471. SLUB is a slab allocator that minimizes cache line usage
  472. instead of managing queues of cached objects (SLAB approach).
  473. Per cpu caching is realized using slabs of objects instead
  474. of queues of objects. SLUB can use memory efficiently
  475. and has enhanced diagnostics.
  476. config SLOB
  477. depends on EMBEDDED
  478. bool "SLOB (Simple Allocator)"
  479. help
  480. SLOB replaces the SLAB allocator with a drastically simpler
  481. allocator. SLOB is more space efficient than SLAB but does not
  482. scale well (single lock for all operations) and is also highly
  483. susceptible to fragmentation. SLUB can accomplish a higher object
  484. density. It is usually better to use SLUB instead of SLOB.
  485. endchoice
  486. endmenu # General setup
  487. config RT_MUTEXES
  488. boolean
  489. select PLIST
  490. config TINY_SHMEM
  491. default !SHMEM
  492. bool
  493. config BASE_SMALL
  494. int
  495. default 0 if BASE_FULL
  496. default 1 if !BASE_FULL
  497. menuconfig MODULES
  498. bool "Enable loadable module support"
  499. help
  500. Kernel modules are small pieces of compiled code which can
  501. be inserted in the running kernel, rather than being
  502. permanently built into the kernel. You use the "modprobe"
  503. tool to add (and sometimes remove) them. If you say Y here,
  504. many parts of the kernel can be built as modules (by
  505. answering M instead of Y where indicated): this is most
  506. useful for infrequently used options which are not required
  507. for booting. For more information, see the man pages for
  508. modprobe, lsmod, modinfo, insmod and rmmod.
  509. If you say Y here, you will need to run "make
  510. modules_install" to put the modules under /lib/modules/
  511. where modprobe can find them (you may need to be root to do
  512. this).
  513. If unsure, say Y.
  514. config MODULE_UNLOAD
  515. bool "Module unloading"
  516. depends on MODULES
  517. help
  518. Without this option you will not be able to unload any
  519. modules (note that some modules may not be unloadable
  520. anyway), which makes your kernel slightly smaller and
  521. simpler. If unsure, say Y.
  522. config MODULE_FORCE_UNLOAD
  523. bool "Forced module unloading"
  524. depends on MODULE_UNLOAD && EXPERIMENTAL
  525. help
  526. This option allows you to force a module to unload, even if the
  527. kernel believes it is unsafe: the kernel will remove the module
  528. without waiting for anyone to stop using it (using the -f option to
  529. rmmod). This is mainly for kernel developers and desperate users.
  530. If unsure, say N.
  531. config MODVERSIONS
  532. bool "Module versioning support"
  533. depends on MODULES
  534. help
  535. Usually, you have to use modules compiled with your kernel.
  536. Saying Y here makes it sometimes possible to use modules
  537. compiled for different kernels, by adding enough information
  538. to the modules to (hopefully) spot any changes which would
  539. make them incompatible with the kernel you are running. If
  540. unsure, say N.
  541. config MODULE_SRCVERSION_ALL
  542. bool "Source checksum for all modules"
  543. depends on MODULES
  544. help
  545. Modules which contain a MODULE_VERSION get an extra "srcversion"
  546. field inserted into their modinfo section, which contains a
  547. sum of the source files which made it. This helps maintainers
  548. see exactly which source was used to build a module (since
  549. others sometimes change the module source without updating
  550. the version). With this option, such a "srcversion" field
  551. will be created for all modules. If unsure, say N.
  552. config KMOD
  553. bool "Automatic kernel module loading"
  554. depends on MODULES
  555. help
  556. Normally when you have selected some parts of the kernel to
  557. be created as kernel modules, you must load them (using the
  558. "modprobe" command) before you can use them. If you say Y
  559. here, some parts of the kernel will be able to load modules
  560. automatically: when a part of the kernel needs a module, it
  561. runs modprobe with the appropriate arguments, thereby
  562. loading the module if it is available. If unsure, say Y.
  563. config STOP_MACHINE
  564. bool
  565. default y
  566. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  567. help
  568. Need stop_machine() primitive.
  569. source "block/Kconfig"