Kconfig 28 KB

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  1. config ARCH
  2. string
  3. option env="ARCH"
  4. config KERNELVERSION
  5. string
  6. option env="KERNELVERSION"
  7. config DEFCONFIG_LIST
  8. string
  9. depends on !UML
  10. option defconfig_list
  11. default "/lib/modules/$UNAME_RELEASE/.config"
  12. default "/etc/kernel-config"
  13. default "/boot/config-$UNAME_RELEASE"
  14. default "arch/$ARCH/defconfig"
  15. menu "General setup"
  16. config EXPERIMENTAL
  17. bool "Prompt for development and/or incomplete code/drivers"
  18. ---help---
  19. Some of the various things that Linux supports (such as network
  20. drivers, file systems, network protocols, etc.) can be in a state
  21. of development where the functionality, stability, or the level of
  22. testing is not yet high enough for general use. This is usually
  23. known as the "alpha-test" phase among developers. If a feature is
  24. currently in alpha-test, then the developers usually discourage
  25. uninformed widespread use of this feature by the general public to
  26. avoid "Why doesn't this work?" type mail messages. However, active
  27. testing and use of these systems is welcomed. Just be aware that it
  28. may not meet the normal level of reliability or it may fail to work
  29. in some special cases. Detailed bug reports from people familiar
  30. with the kernel internals are usually welcomed by the developers
  31. (before submitting bug reports, please read the documents
  32. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  33. <file:Documentation/BUG-HUNTING>, and
  34. <file:Documentation/oops-tracing.txt> in the kernel source).
  35. This option will also make obsoleted drivers available. These are
  36. drivers that have been replaced by something else, and/or are
  37. scheduled to be removed in a future kernel release.
  38. Unless you intend to help test and develop a feature or driver that
  39. falls into this category, or you have a situation that requires
  40. using these features, you should probably say N here, which will
  41. cause the configurator to present you with fewer choices. If
  42. you say Y here, you will be offered the choice of using features or
  43. drivers that are currently considered to be in the alpha-test phase.
  44. config BROKEN
  45. bool
  46. config BROKEN_ON_SMP
  47. bool
  48. depends on BROKEN || !SMP
  49. default y
  50. config LOCK_KERNEL
  51. bool
  52. depends on SMP || PREEMPT
  53. default y
  54. config INIT_ENV_ARG_LIMIT
  55. int
  56. default 32 if !UML
  57. default 128 if UML
  58. help
  59. Maximum of each of the number of arguments and environment
  60. variables passed to init from the kernel command line.
  61. config LOCALVERSION
  62. string "Local version - append to kernel release"
  63. help
  64. Append an extra string to the end of your kernel version.
  65. This will show up when you type uname, for example.
  66. The string you set here will be appended after the contents of
  67. any files with a filename matching localversion* in your
  68. object and source tree, in that order. Your total string can
  69. be a maximum of 64 characters.
  70. config LOCALVERSION_AUTO
  71. bool "Automatically append version information to the version string"
  72. default y
  73. help
  74. This will try to automatically determine if the current tree is a
  75. release tree by looking for git tags that belong to the current
  76. top of tree revision.
  77. A string of the format -gxxxxxxxx will be added to the localversion
  78. if a git-based tree is found. The string generated by this will be
  79. appended after any matching localversion* files, and after the value
  80. set in CONFIG_LOCALVERSION.
  81. (The actual string used here is the first eight characters produced
  82. by running the command:
  83. $ git rev-parse --verify HEAD
  84. which is done within the script "scripts/setlocalversion".)
  85. config SWAP
  86. bool "Support for paging of anonymous memory (swap)"
  87. depends on MMU && BLOCK
  88. default y
  89. help
  90. This option allows you to choose whether you want to have support
  91. for so called swap devices or swap files in your kernel that are
  92. used to provide more virtual memory than the actual RAM present
  93. in your computer. If unsure say Y.
  94. config SYSVIPC
  95. bool "System V IPC"
  96. ---help---
  97. Inter Process Communication is a suite of library functions and
  98. system calls which let processes (running programs) synchronize and
  99. exchange information. It is generally considered to be a good thing,
  100. and some programs won't run unless you say Y here. In particular, if
  101. you want to run the DOS emulator dosemu under Linux (read the
  102. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  103. you'll need to say Y here.
  104. You can find documentation about IPC with "info ipc" and also in
  105. section 6.4 of the Linux Programmer's Guide, available from
  106. <http://www.tldp.org/guides.html>.
  107. config SYSVIPC_SYSCTL
  108. bool
  109. depends on SYSVIPC
  110. depends on SYSCTL
  111. default y
  112. config POSIX_MQUEUE
  113. bool "POSIX Message Queues"
  114. depends on NET && EXPERIMENTAL
  115. ---help---
  116. POSIX variant of message queues is a part of IPC. In POSIX message
  117. queues every message has a priority which decides about succession
  118. of receiving it by a process. If you want to compile and run
  119. programs written e.g. for Solaris with use of its POSIX message
  120. queues (functions mq_*) say Y here.
  121. POSIX message queues are visible as a filesystem called 'mqueue'
  122. and can be mounted somewhere if you want to do filesystem
  123. operations on message queues.
  124. If unsure, say Y.
  125. config BSD_PROCESS_ACCT
  126. bool "BSD Process Accounting"
  127. help
  128. If you say Y here, a user level program will be able to instruct the
  129. kernel (via a special system call) to write process accounting
  130. information to a file: whenever a process exits, information about
  131. that process will be appended to the file by the kernel. The
  132. information includes things such as creation time, owning user,
  133. command name, memory usage, controlling terminal etc. (the complete
  134. list is in the struct acct in <file:include/linux/acct.h>). It is
  135. up to the user level program to do useful things with this
  136. information. This is generally a good idea, so say Y.
  137. config BSD_PROCESS_ACCT_V3
  138. bool "BSD Process Accounting version 3 file format"
  139. depends on BSD_PROCESS_ACCT
  140. default n
  141. help
  142. If you say Y here, the process accounting information is written
  143. in a new file format that also logs the process IDs of each
  144. process and it's parent. Note that this file format is incompatible
  145. with previous v0/v1/v2 file formats, so you will need updated tools
  146. for processing it. A preliminary version of these tools is available
  147. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  148. config TASKSTATS
  149. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  150. depends on NET
  151. default n
  152. help
  153. Export selected statistics for tasks/processes through the
  154. generic netlink interface. Unlike BSD process accounting, the
  155. statistics are available during the lifetime of tasks/processes as
  156. responses to commands. Like BSD accounting, they are sent to user
  157. space on task exit.
  158. Say N if unsure.
  159. config TASK_DELAY_ACCT
  160. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  161. depends on TASKSTATS
  162. help
  163. Collect information on time spent by a task waiting for system
  164. resources like cpu, synchronous block I/O completion and swapping
  165. in pages. Such statistics can help in setting a task's priorities
  166. relative to other tasks for cpu, io, rss limits etc.
  167. Say N if unsure.
  168. config TASK_XACCT
  169. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  170. depends on TASKSTATS
  171. help
  172. Collect extended task accounting data and send the data
  173. to userland for processing over the taskstats interface.
  174. Say N if unsure.
  175. config TASK_IO_ACCOUNTING
  176. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  177. depends on TASK_XACCT
  178. help
  179. Collect information on the number of bytes of storage I/O which this
  180. task has caused.
  181. Say N if unsure.
  182. config AUDIT
  183. bool "Auditing support"
  184. depends on NET
  185. help
  186. Enable auditing infrastructure that can be used with another
  187. kernel subsystem, such as SELinux (which requires this for
  188. logging of avc messages output). Does not do system-call
  189. auditing without CONFIG_AUDITSYSCALL.
  190. config AUDITSYSCALL
  191. bool "Enable system-call auditing support"
  192. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
  193. default y if SECURITY_SELINUX
  194. help
  195. Enable low-overhead system-call auditing infrastructure that
  196. can be used independently or with another kernel subsystem,
  197. such as SELinux. To use audit's filesystem watch feature, please
  198. ensure that INOTIFY is configured.
  199. config AUDIT_TREE
  200. def_bool y
  201. depends on AUDITSYSCALL && INOTIFY
  202. config IKCONFIG
  203. tristate "Kernel .config support"
  204. ---help---
  205. This option enables the complete Linux kernel ".config" file
  206. contents to be saved in the kernel. It provides documentation
  207. of which kernel options are used in a running kernel or in an
  208. on-disk kernel. This information can be extracted from the kernel
  209. image file with the script scripts/extract-ikconfig and used as
  210. input to rebuild the current kernel or to build another kernel.
  211. It can also be extracted from a running kernel by reading
  212. /proc/config.gz if enabled (below).
  213. config IKCONFIG_PROC
  214. bool "Enable access to .config through /proc/config.gz"
  215. depends on IKCONFIG && PROC_FS
  216. ---help---
  217. This option enables access to the kernel configuration file
  218. through /proc/config.gz.
  219. config LOG_BUF_SHIFT
  220. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  221. range 12 21
  222. default 17 if S390 || LOCKDEP
  223. default 16 if X86_NUMAQ || IA64
  224. default 15 if SMP
  225. default 14
  226. help
  227. Select kernel log buffer size as a power of 2.
  228. Defaults and Examples:
  229. 17 => 128 KB for S/390
  230. 16 => 64 KB for x86 NUMAQ or IA-64
  231. 15 => 32 KB for SMP
  232. 14 => 16 KB for uniprocessor
  233. 13 => 8 KB
  234. 12 => 4 KB
  235. config CGROUPS
  236. bool "Control Group support"
  237. help
  238. This option will let you use process cgroup subsystems
  239. such as Cpusets
  240. Say N if unsure.
  241. config CGROUP_DEBUG
  242. bool "Example debug cgroup subsystem"
  243. depends on CGROUPS
  244. help
  245. This option enables a simple cgroup subsystem that
  246. exports useful debugging information about the cgroups
  247. framework
  248. Say N if unsure
  249. config CGROUP_NS
  250. bool "Namespace cgroup subsystem"
  251. depends on CGROUPS
  252. help
  253. Provides a simple namespace cgroup subsystem to
  254. provide hierarchical naming of sets of namespaces,
  255. for instance virtual servers and checkpoint/restart
  256. jobs.
  257. config CPUSETS
  258. bool "Cpuset support"
  259. depends on SMP && CGROUPS
  260. help
  261. This option will let you create and manage CPUSETs which
  262. allow dynamically partitioning a system into sets of CPUs and
  263. Memory Nodes and assigning tasks to run only within those sets.
  264. This is primarily useful on large SMP or NUMA systems.
  265. Say N if unsure.
  266. config GROUP_SCHED
  267. bool "Group CPU scheduler"
  268. default y
  269. help
  270. This feature lets CPU scheduler recognize task groups and control CPU
  271. bandwidth allocation to such task groups.
  272. config FAIR_GROUP_SCHED
  273. bool "Group scheduling for SCHED_OTHER"
  274. depends on GROUP_SCHED
  275. default y
  276. config RT_GROUP_SCHED
  277. bool "Group scheduling for SCHED_RR/FIFO"
  278. depends on EXPERIMENTAL
  279. depends on GROUP_SCHED
  280. default n
  281. help
  282. This feature lets you explicitly allocate real CPU bandwidth
  283. to users or control groups (depending on the "Basis for grouping tasks"
  284. setting below. If enabled, it will also make it impossible to
  285. schedule realtime tasks for non-root users until you allocate
  286. realtime bandwidth for them.
  287. See Documentation/sched-rt-group.txt for more information.
  288. choice
  289. depends on GROUP_SCHED
  290. prompt "Basis for grouping tasks"
  291. default USER_SCHED
  292. config USER_SCHED
  293. bool "user id"
  294. help
  295. This option will choose userid as the basis for grouping
  296. tasks, thus providing equal CPU bandwidth to each user.
  297. config CGROUP_SCHED
  298. bool "Control groups"
  299. depends on CGROUPS
  300. help
  301. This option allows you to create arbitrary task groups
  302. using the "cgroup" pseudo filesystem and control
  303. the cpu bandwidth allocated to each such task group.
  304. Refer to Documentation/cgroups.txt for more information
  305. on "cgroup" pseudo filesystem.
  306. endchoice
  307. config CGROUP_CPUACCT
  308. bool "Simple CPU accounting cgroup subsystem"
  309. depends on CGROUPS
  310. help
  311. Provides a simple Resource Controller for monitoring the
  312. total CPU consumed by the tasks in a cgroup
  313. config RESOURCE_COUNTERS
  314. bool "Resource counters"
  315. help
  316. This option enables controller independent resource accounting
  317. infrastructure that works with cgroups
  318. depends on CGROUPS
  319. config CGROUP_MEM_RES_CTLR
  320. bool "Memory Resource Controller for Control Groups"
  321. depends on CGROUPS && RESOURCE_COUNTERS
  322. help
  323. Provides a memory resource controller that manages both page cache and
  324. RSS memory.
  325. Note that setting this option increases fixed memory overhead
  326. associated with each page of memory in the system by 4/8 bytes
  327. and also increases cache misses because struct page on many 64bit
  328. systems will not fit into a single cache line anymore.
  329. Only enable when you're ok with these trade offs and really
  330. sure you need the memory resource controller.
  331. config SYSFS_DEPRECATED
  332. bool
  333. config SYSFS_DEPRECATED_V2
  334. bool "Create deprecated sysfs files"
  335. depends on SYSFS
  336. default y
  337. select SYSFS_DEPRECATED
  338. help
  339. This option creates deprecated symlinks such as the
  340. "device"-link, the <subsystem>:<name>-link, and the
  341. "bus"-link. It may also add deprecated key in the
  342. uevent environment.
  343. None of these features or values should be used today, as
  344. they export driver core implementation details to userspace
  345. or export properties which can't be kept stable across kernel
  346. releases.
  347. If enabled, this option will also move any device structures
  348. that belong to a class, back into the /sys/class hierarchy, in
  349. order to support older versions of udev and some userspace
  350. programs.
  351. If you are using a distro with the most recent userspace
  352. packages, it should be safe to say N here.
  353. config PROC_PID_CPUSET
  354. bool "Include legacy /proc/<pid>/cpuset file"
  355. depends on CPUSETS
  356. default y
  357. config RELAY
  358. bool "Kernel->user space relay support (formerly relayfs)"
  359. help
  360. This option enables support for relay interface support in
  361. certain file systems (such as debugfs).
  362. It is designed to provide an efficient mechanism for tools and
  363. facilities to relay large amounts of data from kernel space to
  364. user space.
  365. If unsure, say N.
  366. config NAMESPACES
  367. bool "Namespaces support" if EMBEDDED
  368. default !EMBEDDED
  369. help
  370. Provides the way to make tasks work with different objects using
  371. the same id. For example same IPC id may refer to different objects
  372. or same user id or pid may refer to different tasks when used in
  373. different namespaces.
  374. config UTS_NS
  375. bool "UTS namespace"
  376. depends on NAMESPACES
  377. help
  378. In this namespace tasks see different info provided with the
  379. uname() system call
  380. config IPC_NS
  381. bool "IPC namespace"
  382. depends on NAMESPACES && SYSVIPC
  383. help
  384. In this namespace tasks work with IPC ids which correspond to
  385. different IPC objects in different namespaces
  386. config USER_NS
  387. bool "User namespace (EXPERIMENTAL)"
  388. depends on NAMESPACES && EXPERIMENTAL
  389. help
  390. This allows containers, i.e. vservers, to use user namespaces
  391. to provide different user info for different servers.
  392. If unsure, say N.
  393. config PID_NS
  394. bool "PID Namespaces (EXPERIMENTAL)"
  395. default n
  396. depends on NAMESPACES && EXPERIMENTAL
  397. help
  398. Suport process id namespaces. This allows having multiple
  399. process with the same pid as long as they are in different
  400. pid namespaces. This is a building block of containers.
  401. Unless you want to work with an experimental feature
  402. say N here.
  403. config BLK_DEV_INITRD
  404. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  405. depends on BROKEN || !FRV
  406. help
  407. The initial RAM filesystem is a ramfs which is loaded by the
  408. boot loader (loadlin or lilo) and that is mounted as root
  409. before the normal boot procedure. It is typically used to
  410. load modules needed to mount the "real" root file system,
  411. etc. See <file:Documentation/initrd.txt> for details.
  412. If RAM disk support (BLK_DEV_RAM) is also included, this
  413. also enables initial RAM disk (initrd) support and adds
  414. 15 Kbytes (more on some other architectures) to the kernel size.
  415. If unsure say Y.
  416. if BLK_DEV_INITRD
  417. source "usr/Kconfig"
  418. endif
  419. config CC_OPTIMIZE_FOR_SIZE
  420. bool "Optimize for size (Look out for broken compilers!)"
  421. default y
  422. depends on ARM || H8300 || SUPERH || EXPERIMENTAL
  423. help
  424. Enabling this option will pass "-Os" instead of "-O2" to gcc
  425. resulting in a smaller kernel.
  426. WARNING: some versions of gcc may generate incorrect code with this
  427. option. If problems are observed, a gcc upgrade may be needed.
  428. If unsure, say N.
  429. config SYSCTL
  430. bool
  431. menuconfig EMBEDDED
  432. bool "Configure standard kernel features (for small systems)"
  433. help
  434. This option allows certain base kernel options and settings
  435. to be disabled or tweaked. This is for specialized
  436. environments which can tolerate a "non-standard" kernel.
  437. Only use this if you really know what you are doing.
  438. config UID16
  439. bool "Enable 16-bit UID system calls" if EMBEDDED
  440. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  441. default y
  442. help
  443. This enables the legacy 16-bit UID syscall wrappers.
  444. config SYSCTL_SYSCALL
  445. bool "Sysctl syscall support" if EMBEDDED
  446. default y
  447. select SYSCTL
  448. ---help---
  449. sys_sysctl uses binary paths that have been found challenging
  450. to properly maintain and use. The interface in /proc/sys
  451. using paths with ascii names is now the primary path to this
  452. information.
  453. Almost nothing using the binary sysctl interface so if you are
  454. trying to save some space it is probably safe to disable this,
  455. making your kernel marginally smaller.
  456. If unsure say Y here.
  457. config KALLSYMS
  458. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  459. default y
  460. help
  461. Say Y here to let the kernel print out symbolic crash information and
  462. symbolic stack backtraces. This increases the size of the kernel
  463. somewhat, as all symbols have to be loaded into the kernel image.
  464. config KALLSYMS_ALL
  465. bool "Include all symbols in kallsyms"
  466. depends on DEBUG_KERNEL && KALLSYMS
  467. help
  468. Normally kallsyms only contains the symbols of functions, for nicer
  469. OOPS messages. Some debuggers can use kallsyms for other
  470. symbols too: say Y here to include all symbols, if you need them
  471. and you don't care about adding 300k to the size of your kernel.
  472. Say N.
  473. config KALLSYMS_EXTRA_PASS
  474. bool "Do an extra kallsyms pass"
  475. depends on KALLSYMS
  476. help
  477. If kallsyms is not working correctly, the build will fail with
  478. inconsistent kallsyms data. If that occurs, log a bug report and
  479. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  480. Always say N here unless you find a bug in kallsyms, which must be
  481. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  482. you wait for kallsyms to be fixed.
  483. config HOTPLUG
  484. bool "Support for hot-pluggable devices" if EMBEDDED
  485. default y
  486. help
  487. This option is provided for the case where no hotplug or uevent
  488. capabilities is wanted by the kernel. You should only consider
  489. disabling this option for embedded systems that do not use modules, a
  490. dynamic /dev tree, or dynamic device discovery. Just say Y.
  491. config PRINTK
  492. default y
  493. bool "Enable support for printk" if EMBEDDED
  494. help
  495. This option enables normal printk support. Removing it
  496. eliminates most of the message strings from the kernel image
  497. and makes the kernel more or less silent. As this makes it
  498. very difficult to diagnose system problems, saying N here is
  499. strongly discouraged.
  500. config BUG
  501. bool "BUG() support" if EMBEDDED
  502. default y
  503. help
  504. Disabling this option eliminates support for BUG and WARN, reducing
  505. the size of your kernel image and potentially quietly ignoring
  506. numerous fatal conditions. You should only consider disabling this
  507. option for embedded systems with no facilities for reporting errors.
  508. Just say Y.
  509. config ELF_CORE
  510. default y
  511. bool "Enable ELF core dumps" if EMBEDDED
  512. help
  513. Enable support for generating core dumps. Disabling saves about 4k.
  514. config COMPAT_BRK
  515. bool "Disable heap randomization"
  516. default y
  517. help
  518. Randomizing heap placement makes heap exploits harder, but it
  519. also breaks ancient binaries (including anything libc5 based).
  520. This option changes the bootup default to heap randomization
  521. disabled, and can be overriden runtime by setting
  522. /proc/sys/kernel/randomize_va_space to 2.
  523. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  524. config BASE_FULL
  525. default y
  526. bool "Enable full-sized data structures for core" if EMBEDDED
  527. help
  528. Disabling this option reduces the size of miscellaneous core
  529. kernel data structures. This saves memory on small machines,
  530. but may reduce performance.
  531. config FUTEX
  532. bool "Enable futex support" if EMBEDDED
  533. default y
  534. select RT_MUTEXES
  535. help
  536. Disabling this option will cause the kernel to be built without
  537. support for "fast userspace mutexes". The resulting kernel may not
  538. run glibc-based applications correctly.
  539. config ANON_INODES
  540. bool
  541. config EPOLL
  542. bool "Enable eventpoll support" if EMBEDDED
  543. default y
  544. select ANON_INODES
  545. help
  546. Disabling this option will cause the kernel to be built without
  547. support for epoll family of system calls.
  548. config SIGNALFD
  549. bool "Enable signalfd() system call" if EMBEDDED
  550. select ANON_INODES
  551. default y
  552. help
  553. Enable the signalfd() system call that allows to receive signals
  554. on a file descriptor.
  555. If unsure, say Y.
  556. config TIMERFD
  557. bool "Enable timerfd() system call" if EMBEDDED
  558. select ANON_INODES
  559. default y
  560. help
  561. Enable the timerfd() system call that allows to receive timer
  562. events on a file descriptor.
  563. If unsure, say Y.
  564. config EVENTFD
  565. bool "Enable eventfd() system call" if EMBEDDED
  566. select ANON_INODES
  567. default y
  568. help
  569. Enable the eventfd() system call that allows to receive both
  570. kernel notification (ie. KAIO) or userspace notifications.
  571. If unsure, say Y.
  572. config SHMEM
  573. bool "Use full shmem filesystem" if EMBEDDED
  574. default y
  575. depends on MMU
  576. help
  577. The shmem is an internal filesystem used to manage shared memory.
  578. It is backed by swap and manages resource limits. It is also exported
  579. to userspace as tmpfs if TMPFS is enabled. Disabling this
  580. option replaces shmem and tmpfs with the much simpler ramfs code,
  581. which may be appropriate on small systems without swap.
  582. config VM_EVENT_COUNTERS
  583. default y
  584. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  585. help
  586. VM event counters are needed for event counts to be shown.
  587. This option allows the disabling of the VM event counters
  588. on EMBEDDED systems. /proc/vmstat will only show page counts
  589. if VM event counters are disabled.
  590. config SLUB_DEBUG
  591. default y
  592. bool "Enable SLUB debugging support" if EMBEDDED
  593. depends on SLUB
  594. help
  595. SLUB has extensive debug support features. Disabling these can
  596. result in significant savings in code size. This also disables
  597. SLUB sysfs support. /sys/slab will not exist and there will be
  598. no support for cache validation etc.
  599. choice
  600. prompt "Choose SLAB allocator"
  601. default SLUB
  602. help
  603. This option allows to select a slab allocator.
  604. config SLAB
  605. bool "SLAB"
  606. help
  607. The regular slab allocator that is established and known to work
  608. well in all environments. It organizes cache hot objects in
  609. per cpu and per node queues. SLAB is the default choice for
  610. a slab allocator.
  611. config SLUB
  612. bool "SLUB (Unqueued Allocator)"
  613. help
  614. SLUB is a slab allocator that minimizes cache line usage
  615. instead of managing queues of cached objects (SLAB approach).
  616. Per cpu caching is realized using slabs of objects instead
  617. of queues of objects. SLUB can use memory efficiently
  618. and has enhanced diagnostics.
  619. config SLOB
  620. depends on EMBEDDED
  621. bool "SLOB (Simple Allocator)"
  622. help
  623. SLOB replaces the stock allocator with a drastically simpler
  624. allocator. SLOB is generally more space efficient but
  625. does not perform as well on large systems.
  626. endchoice
  627. config PROFILING
  628. bool "Profiling support (EXPERIMENTAL)"
  629. help
  630. Say Y here to enable the extended profiling support mechanisms used
  631. by profilers such as OProfile.
  632. config MARKERS
  633. bool "Activate markers"
  634. help
  635. Place an empty function call at each marker site. Can be
  636. dynamically changed for a probe function.
  637. source "arch/Kconfig"
  638. config PROC_PAGE_MONITOR
  639. default y
  640. depends on PROC_FS && MMU
  641. bool "Enable /proc page monitoring" if EMBEDDED
  642. help
  643. Various /proc files exist to monitor process memory utilization:
  644. /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
  645. /proc/kpagecount, and /proc/kpageflags. Disabling these
  646. interfaces will reduce the size of the kernel by approximately 4kb.
  647. endmenu # General setup
  648. config SLABINFO
  649. bool
  650. depends on PROC_FS
  651. depends on SLAB || SLUB_DEBUG
  652. default y
  653. config RT_MUTEXES
  654. boolean
  655. select PLIST
  656. config TINY_SHMEM
  657. default !SHMEM
  658. bool
  659. config BASE_SMALL
  660. int
  661. default 0 if BASE_FULL
  662. default 1 if !BASE_FULL
  663. menuconfig MODULES
  664. bool "Enable loadable module support"
  665. help
  666. Kernel modules are small pieces of compiled code which can
  667. be inserted in the running kernel, rather than being
  668. permanently built into the kernel. You use the "modprobe"
  669. tool to add (and sometimes remove) them. If you say Y here,
  670. many parts of the kernel can be built as modules (by
  671. answering M instead of Y where indicated): this is most
  672. useful for infrequently used options which are not required
  673. for booting. For more information, see the man pages for
  674. modprobe, lsmod, modinfo, insmod and rmmod.
  675. If you say Y here, you will need to run "make
  676. modules_install" to put the modules under /lib/modules/
  677. where modprobe can find them (you may need to be root to do
  678. this).
  679. If unsure, say Y.
  680. config MODULE_UNLOAD
  681. bool "Module unloading"
  682. depends on MODULES
  683. help
  684. Without this option you will not be able to unload any
  685. modules (note that some modules may not be unloadable
  686. anyway), which makes your kernel slightly smaller and
  687. simpler. If unsure, say Y.
  688. config MODULE_FORCE_UNLOAD
  689. bool "Forced module unloading"
  690. depends on MODULE_UNLOAD && EXPERIMENTAL
  691. help
  692. This option allows you to force a module to unload, even if the
  693. kernel believes it is unsafe: the kernel will remove the module
  694. without waiting for anyone to stop using it (using the -f option to
  695. rmmod). This is mainly for kernel developers and desperate users.
  696. If unsure, say N.
  697. config MODVERSIONS
  698. bool "Module versioning support"
  699. depends on MODULES
  700. help
  701. Usually, you have to use modules compiled with your kernel.
  702. Saying Y here makes it sometimes possible to use modules
  703. compiled for different kernels, by adding enough information
  704. to the modules to (hopefully) spot any changes which would
  705. make them incompatible with the kernel you are running. If
  706. unsure, say N.
  707. config MODULE_SRCVERSION_ALL
  708. bool "Source checksum for all modules"
  709. depends on MODULES
  710. help
  711. Modules which contain a MODULE_VERSION get an extra "srcversion"
  712. field inserted into their modinfo section, which contains a
  713. sum of the source files which made it. This helps maintainers
  714. see exactly which source was used to build a module (since
  715. others sometimes change the module source without updating
  716. the version). With this option, such a "srcversion" field
  717. will be created for all modules. If unsure, say N.
  718. config KMOD
  719. bool "Automatic kernel module loading"
  720. depends on MODULES
  721. help
  722. Normally when you have selected some parts of the kernel to
  723. be created as kernel modules, you must load them (using the
  724. "modprobe" command) before you can use them. If you say Y
  725. here, some parts of the kernel will be able to load modules
  726. automatically: when a part of the kernel needs a module, it
  727. runs modprobe with the appropriate arguments, thereby
  728. loading the module if it is available. If unsure, say Y.
  729. config STOP_MACHINE
  730. bool
  731. default y
  732. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  733. help
  734. Need stop_machine() primitive.
  735. source "block/Kconfig"
  736. config PREEMPT_NOTIFIERS
  737. bool
  738. config CLASSIC_RCU
  739. def_bool !PREEMPT_RCU
  740. help
  741. This option selects the classic RCU implementation that is
  742. designed for best read-side performance on non-realtime
  743. systems. Classic RCU is the default. Note that the
  744. PREEMPT_RCU symbol is used to select/deselect this option.