Kconfig 29 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 drivers that have been replaced by something else, and/or are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
  223. help
  224. Select kernel log buffer size as a power of 2.
  225. Examples:
  226. 17 => 128 KB
  227. 16 => 64 KB
  228. 15 => 32 KB
  229. 14 => 16 KB
  230. 13 => 8 KB
  231. 12 => 4 KB
  232. config CGROUPS
  233. bool "Control Group support"
  234. help
  235. This option will let you use process cgroup subsystems
  236. such as Cpusets
  237. Say N if unsure.
  238. config CGROUP_DEBUG
  239. bool "Example debug cgroup subsystem"
  240. depends on CGROUPS
  241. default n
  242. help
  243. This option enables a simple cgroup subsystem that
  244. exports useful debugging information about the cgroups
  245. framework
  246. Say N if unsure
  247. config CGROUP_NS
  248. bool "Namespace cgroup subsystem"
  249. depends on CGROUPS
  250. help
  251. Provides a simple namespace cgroup subsystem to
  252. provide hierarchical naming of sets of namespaces,
  253. for instance virtual servers and checkpoint/restart
  254. jobs.
  255. config CGROUP_DEVICE
  256. bool "Device controller for cgroups"
  257. depends on CGROUPS && EXPERIMENTAL
  258. help
  259. Provides a cgroup implementing whitelists for devices which
  260. a process in the cgroup can mknod or open.
  261. config CPUSETS
  262. bool "Cpuset support"
  263. depends on SMP && CGROUPS
  264. help
  265. This option will let you create and manage CPUSETs which
  266. allow dynamically partitioning a system into sets of CPUs and
  267. Memory Nodes and assigning tasks to run only within those sets.
  268. This is primarily useful on large SMP or NUMA systems.
  269. Say N if unsure.
  270. #
  271. # Architectures with an unreliable sched_clock() should select this:
  272. #
  273. config HAVE_UNSTABLE_SCHED_CLOCK
  274. bool
  275. config GROUP_SCHED
  276. bool "Group CPU scheduler"
  277. depends on EXPERIMENTAL
  278. default n
  279. help
  280. This feature lets CPU scheduler recognize task groups and control CPU
  281. bandwidth allocation to such task groups.
  282. config FAIR_GROUP_SCHED
  283. bool "Group scheduling for SCHED_OTHER"
  284. depends on GROUP_SCHED
  285. default GROUP_SCHED
  286. config RT_GROUP_SCHED
  287. bool "Group scheduling for SCHED_RR/FIFO"
  288. depends on EXPERIMENTAL
  289. depends on GROUP_SCHED
  290. default n
  291. help
  292. This feature lets you explicitly allocate real CPU bandwidth
  293. to users or control groups (depending on the "Basis for grouping tasks"
  294. setting below. If enabled, it will also make it impossible to
  295. schedule realtime tasks for non-root users until you allocate
  296. realtime bandwidth for them.
  297. See Documentation/sched-rt-group.txt for more information.
  298. choice
  299. depends on GROUP_SCHED
  300. prompt "Basis for grouping tasks"
  301. default USER_SCHED
  302. config USER_SCHED
  303. bool "user id"
  304. help
  305. This option will choose userid as the basis for grouping
  306. tasks, thus providing equal CPU bandwidth to each user.
  307. config CGROUP_SCHED
  308. bool "Control groups"
  309. depends on CGROUPS
  310. help
  311. This option allows you to create arbitrary task groups
  312. using the "cgroup" pseudo filesystem and control
  313. the cpu bandwidth allocated to each such task group.
  314. Refer to Documentation/cgroups.txt for more information
  315. on "cgroup" pseudo filesystem.
  316. endchoice
  317. config CGROUP_CPUACCT
  318. bool "Simple CPU accounting cgroup subsystem"
  319. depends on CGROUPS
  320. help
  321. Provides a simple Resource Controller for monitoring the
  322. total CPU consumed by the tasks in a cgroup
  323. config RESOURCE_COUNTERS
  324. bool "Resource counters"
  325. help
  326. This option enables controller independent resource accounting
  327. infrastructure that works with cgroups
  328. depends on CGROUPS
  329. config MM_OWNER
  330. bool
  331. config CGROUP_MEM_RES_CTLR
  332. bool "Memory Resource Controller for Control Groups"
  333. depends on CGROUPS && RESOURCE_COUNTERS
  334. select MM_OWNER
  335. help
  336. Provides a memory resource controller that manages both page cache and
  337. RSS memory.
  338. Note that setting this option increases fixed memory overhead
  339. associated with each page of memory in the system by 4/8 bytes
  340. and also increases cache misses because struct page on many 64bit
  341. systems will not fit into a single cache line anymore.
  342. Only enable when you're ok with these trade offs and really
  343. sure you need the memory resource controller.
  344. This config option also selects MM_OWNER config option, which
  345. could in turn add some fork/exit overhead.
  346. config SYSFS_DEPRECATED
  347. bool
  348. config SYSFS_DEPRECATED_V2
  349. bool "Create deprecated sysfs files"
  350. depends on SYSFS
  351. default y
  352. select SYSFS_DEPRECATED
  353. help
  354. This option creates deprecated symlinks such as the
  355. "device"-link, the <subsystem>:<name>-link, and the
  356. "bus"-link. It may also add deprecated key in the
  357. uevent environment.
  358. None of these features or values should be used today, as
  359. they export driver core implementation details to userspace
  360. or export properties which can't be kept stable across kernel
  361. releases.
  362. If enabled, this option will also move any device structures
  363. that belong to a class, back into the /sys/class hierarchy, in
  364. order to support older versions of udev and some userspace
  365. programs.
  366. If you are using a distro with the most recent userspace
  367. packages, it should be safe to say N here.
  368. config PROC_PID_CPUSET
  369. bool "Include legacy /proc/<pid>/cpuset file"
  370. depends on CPUSETS
  371. default y
  372. config RELAY
  373. bool "Kernel->user space relay support (formerly relayfs)"
  374. help
  375. This option enables support for relay interface support in
  376. certain file systems (such as debugfs).
  377. It is designed to provide an efficient mechanism for tools and
  378. facilities to relay large amounts of data from kernel space to
  379. user space.
  380. If unsure, say N.
  381. config NAMESPACES
  382. bool "Namespaces support" if EMBEDDED
  383. default !EMBEDDED
  384. help
  385. Provides the way to make tasks work with different objects using
  386. the same id. For example same IPC id may refer to different objects
  387. or same user id or pid may refer to different tasks when used in
  388. different namespaces.
  389. config UTS_NS
  390. bool "UTS namespace"
  391. depends on NAMESPACES
  392. help
  393. In this namespace tasks see different info provided with the
  394. uname() system call
  395. config IPC_NS
  396. bool "IPC namespace"
  397. depends on NAMESPACES && SYSVIPC
  398. help
  399. In this namespace tasks work with IPC ids which correspond to
  400. different IPC objects in different namespaces
  401. config USER_NS
  402. bool "User namespace (EXPERIMENTAL)"
  403. depends on NAMESPACES && EXPERIMENTAL
  404. help
  405. This allows containers, i.e. vservers, to use user namespaces
  406. to provide different user info for different servers.
  407. If unsure, say N.
  408. config PID_NS
  409. bool "PID Namespaces (EXPERIMENTAL)"
  410. default n
  411. depends on NAMESPACES && EXPERIMENTAL
  412. help
  413. Suport process id namespaces. This allows having multiple
  414. process with the same pid as long as they are in different
  415. pid namespaces. This is a building block of containers.
  416. Unless you want to work with an experimental feature
  417. say N here.
  418. config BLK_DEV_INITRD
  419. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  420. depends on BROKEN || !FRV
  421. help
  422. The initial RAM filesystem is a ramfs which is loaded by the
  423. boot loader (loadlin or lilo) and that is mounted as root
  424. before the normal boot procedure. It is typically used to
  425. load modules needed to mount the "real" root file system,
  426. etc. See <file:Documentation/initrd.txt> for details.
  427. If RAM disk support (BLK_DEV_RAM) is also included, this
  428. also enables initial RAM disk (initrd) support and adds
  429. 15 Kbytes (more on some other architectures) to the kernel size.
  430. If unsure say Y.
  431. if BLK_DEV_INITRD
  432. source "usr/Kconfig"
  433. endif
  434. config CC_OPTIMIZE_FOR_SIZE
  435. bool "Optimize for size"
  436. default y
  437. help
  438. Enabling this option will pass "-Os" instead of "-O2" to gcc
  439. resulting in a smaller kernel.
  440. If unsure, say N.
  441. config SYSCTL
  442. bool
  443. menuconfig EMBEDDED
  444. bool "Configure standard kernel features (for small systems)"
  445. help
  446. This option allows certain base kernel options and settings
  447. to be disabled or tweaked. This is for specialized
  448. environments which can tolerate a "non-standard" kernel.
  449. Only use this if you really know what you are doing.
  450. config UID16
  451. bool "Enable 16-bit UID system calls" if EMBEDDED
  452. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
  453. default y
  454. help
  455. This enables the legacy 16-bit UID syscall wrappers.
  456. config SYSCTL_SYSCALL
  457. bool "Sysctl syscall support" if EMBEDDED
  458. default y
  459. select SYSCTL
  460. ---help---
  461. sys_sysctl uses binary paths that have been found challenging
  462. to properly maintain and use. The interface in /proc/sys
  463. using paths with ascii names is now the primary path to this
  464. information.
  465. Almost nothing using the binary sysctl interface so if you are
  466. trying to save some space it is probably safe to disable this,
  467. making your kernel marginally smaller.
  468. If unsure say Y here.
  469. config SYSCTL_SYSCALL_CHECK
  470. bool "Sysctl checks" if EMBEDDED
  471. depends on SYSCTL_SYSCALL
  472. default y
  473. ---help---
  474. sys_sysctl uses binary paths that have been found challenging
  475. to properly maintain and use. This enables checks that help
  476. you to keep things correct.
  477. If unsure say Y here.
  478. config KALLSYMS
  479. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  480. default y
  481. help
  482. Say Y here to let the kernel print out symbolic crash information and
  483. symbolic stack backtraces. This increases the size of the kernel
  484. somewhat, as all symbols have to be loaded into the kernel image.
  485. config KALLSYMS_ALL
  486. bool "Include all symbols in kallsyms"
  487. depends on DEBUG_KERNEL && KALLSYMS
  488. help
  489. Normally kallsyms only contains the symbols of functions, for nicer
  490. OOPS messages. Some debuggers can use kallsyms for other
  491. symbols too: say Y here to include all symbols, if you need them
  492. and you don't care about adding 300k to the size of your kernel.
  493. Say N.
  494. config KALLSYMS_EXTRA_PASS
  495. bool "Do an extra kallsyms pass"
  496. depends on KALLSYMS
  497. help
  498. If kallsyms is not working correctly, the build will fail with
  499. inconsistent kallsyms data. If that occurs, log a bug report and
  500. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  501. Always say N here unless you find a bug in kallsyms, which must be
  502. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  503. you wait for kallsyms to be fixed.
  504. config HOTPLUG
  505. bool "Support for hot-pluggable devices" if EMBEDDED
  506. default y
  507. help
  508. This option is provided for the case where no hotplug or uevent
  509. capabilities is wanted by the kernel. You should only consider
  510. disabling this option for embedded systems that do not use modules, a
  511. dynamic /dev tree, or dynamic device discovery. Just say Y.
  512. config PRINTK
  513. default y
  514. bool "Enable support for printk" if EMBEDDED
  515. help
  516. This option enables normal printk support. Removing it
  517. eliminates most of the message strings from the kernel image
  518. and makes the kernel more or less silent. As this makes it
  519. very difficult to diagnose system problems, saying N here is
  520. strongly discouraged.
  521. config BUG
  522. bool "BUG() support" if EMBEDDED
  523. default y
  524. help
  525. Disabling this option eliminates support for BUG and WARN, reducing
  526. the size of your kernel image and potentially quietly ignoring
  527. numerous fatal conditions. You should only consider disabling this
  528. option for embedded systems with no facilities for reporting errors.
  529. Just say Y.
  530. config ELF_CORE
  531. default y
  532. bool "Enable ELF core dumps" if EMBEDDED
  533. help
  534. Enable support for generating core dumps. Disabling saves about 4k.
  535. config PCSPKR_PLATFORM
  536. bool "Enable PC-Speaker support" if EMBEDDED
  537. depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
  538. default y
  539. help
  540. This option allows to disable the internal PC-Speaker
  541. support, saving some memory.
  542. config COMPAT_BRK
  543. bool "Disable heap randomization"
  544. default y
  545. help
  546. Randomizing heap placement makes heap exploits harder, but it
  547. also breaks ancient binaries (including anything libc5 based).
  548. This option changes the bootup default to heap randomization
  549. disabled, and can be overriden runtime by setting
  550. /proc/sys/kernel/randomize_va_space to 2.
  551. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  552. config BASE_FULL
  553. default y
  554. bool "Enable full-sized data structures for core" if EMBEDDED
  555. help
  556. Disabling this option reduces the size of miscellaneous core
  557. kernel data structures. This saves memory on small machines,
  558. but may reduce performance.
  559. config FUTEX
  560. bool "Enable futex support" if EMBEDDED
  561. default y
  562. select RT_MUTEXES
  563. help
  564. Disabling this option will cause the kernel to be built without
  565. support for "fast userspace mutexes". The resulting kernel may not
  566. run glibc-based applications correctly.
  567. config ANON_INODES
  568. bool
  569. config EPOLL
  570. bool "Enable eventpoll support" if EMBEDDED
  571. default y
  572. select ANON_INODES
  573. help
  574. Disabling this option will cause the kernel to be built without
  575. support for epoll family of system calls.
  576. config SIGNALFD
  577. bool "Enable signalfd() system call" if EMBEDDED
  578. select ANON_INODES
  579. default y
  580. help
  581. Enable the signalfd() system call that allows to receive signals
  582. on a file descriptor.
  583. If unsure, say Y.
  584. config TIMERFD
  585. bool "Enable timerfd() system call" if EMBEDDED
  586. select ANON_INODES
  587. default y
  588. help
  589. Enable the timerfd() system call that allows to receive timer
  590. events on a file descriptor.
  591. If unsure, say Y.
  592. config EVENTFD
  593. bool "Enable eventfd() system call" if EMBEDDED
  594. select ANON_INODES
  595. default y
  596. help
  597. Enable the eventfd() system call that allows to receive both
  598. kernel notification (ie. KAIO) or userspace notifications.
  599. If unsure, say Y.
  600. config SHMEM
  601. bool "Use full shmem filesystem" if EMBEDDED
  602. default y
  603. depends on MMU
  604. help
  605. The shmem is an internal filesystem used to manage shared memory.
  606. It is backed by swap and manages resource limits. It is also exported
  607. to userspace as tmpfs if TMPFS is enabled. Disabling this
  608. option replaces shmem and tmpfs with the much simpler ramfs code,
  609. which may be appropriate on small systems without swap.
  610. config VM_EVENT_COUNTERS
  611. default y
  612. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  613. help
  614. VM event counters are needed for event counts to be shown.
  615. This option allows the disabling of the VM event counters
  616. on EMBEDDED systems. /proc/vmstat will only show page counts
  617. if VM event counters are disabled.
  618. config SLUB_DEBUG
  619. default y
  620. bool "Enable SLUB debugging support" if EMBEDDED
  621. depends on SLUB && SYSFS
  622. help
  623. SLUB has extensive debug support features. Disabling these can
  624. result in significant savings in code size. This also disables
  625. SLUB sysfs support. /sys/slab will not exist and there will be
  626. no support for cache validation etc.
  627. choice
  628. prompt "Choose SLAB allocator"
  629. default SLUB
  630. help
  631. This option allows to select a slab allocator.
  632. config SLAB
  633. bool "SLAB"
  634. help
  635. The regular slab allocator that is established and known to work
  636. well in all environments. It organizes cache hot objects in
  637. per cpu and per node queues. SLAB is the default choice for
  638. a slab allocator.
  639. config SLUB
  640. bool "SLUB (Unqueued Allocator)"
  641. help
  642. SLUB is a slab allocator that minimizes cache line usage
  643. instead of managing queues of cached objects (SLAB approach).
  644. Per cpu caching is realized using slabs of objects instead
  645. of queues of objects. SLUB can use memory efficiently
  646. and has enhanced diagnostics.
  647. config SLOB
  648. depends on EMBEDDED
  649. bool "SLOB (Simple Allocator)"
  650. help
  651. SLOB replaces the stock allocator with a drastically simpler
  652. allocator. SLOB is generally more space efficient but
  653. does not perform as well on large systems.
  654. endchoice
  655. config PROFILING
  656. bool "Profiling support (EXPERIMENTAL)"
  657. help
  658. Say Y here to enable the extended profiling support mechanisms used
  659. by profilers such as OProfile.
  660. config MARKERS
  661. bool "Activate markers"
  662. help
  663. Place an empty function call at each marker site. Can be
  664. dynamically changed for a probe function.
  665. source "arch/Kconfig"
  666. config PROC_PAGE_MONITOR
  667. default y
  668. depends on PROC_FS && MMU
  669. bool "Enable /proc page monitoring" if EMBEDDED
  670. help
  671. Various /proc files exist to monitor process memory utilization:
  672. /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
  673. /proc/kpagecount, and /proc/kpageflags. Disabling these
  674. interfaces will reduce the size of the kernel by approximately 4kb.
  675. endmenu # General setup
  676. config SLABINFO
  677. bool
  678. depends on PROC_FS
  679. depends on SLAB || SLUB_DEBUG
  680. default y
  681. config RT_MUTEXES
  682. boolean
  683. select PLIST
  684. config TINY_SHMEM
  685. default !SHMEM
  686. bool
  687. config BASE_SMALL
  688. int
  689. default 0 if BASE_FULL
  690. default 1 if !BASE_FULL
  691. menuconfig MODULES
  692. bool "Enable loadable module support"
  693. help
  694. Kernel modules are small pieces of compiled code which can
  695. be inserted in the running kernel, rather than being
  696. permanently built into the kernel. You use the "modprobe"
  697. tool to add (and sometimes remove) them. If you say Y here,
  698. many parts of the kernel can be built as modules (by
  699. answering M instead of Y where indicated): this is most
  700. useful for infrequently used options which are not required
  701. for booting. For more information, see the man pages for
  702. modprobe, lsmod, modinfo, insmod and rmmod.
  703. If you say Y here, you will need to run "make
  704. modules_install" to put the modules under /lib/modules/
  705. where modprobe can find them (you may need to be root to do
  706. this).
  707. If unsure, say Y.
  708. config MODULE_FORCE_LOAD
  709. bool "Forced module loading"
  710. depends on MODULES
  711. default n
  712. help
  713. Allow loading of modules without version information (ie. modprobe
  714. --force). Forced module loading sets the 'F' (forced) taint flag and
  715. is usually a really bad idea.
  716. config MODULE_UNLOAD
  717. bool "Module unloading"
  718. depends on MODULES
  719. help
  720. Without this option you will not be able to unload any
  721. modules (note that some modules may not be unloadable
  722. anyway), which makes your kernel slightly smaller and
  723. simpler. If unsure, say Y.
  724. config MODULE_FORCE_UNLOAD
  725. bool "Forced module unloading"
  726. depends on MODULE_UNLOAD && EXPERIMENTAL
  727. help
  728. This option allows you to force a module to unload, even if the
  729. kernel believes it is unsafe: the kernel will remove the module
  730. without waiting for anyone to stop using it (using the -f option to
  731. rmmod). This is mainly for kernel developers and desperate users.
  732. If unsure, say N.
  733. config MODVERSIONS
  734. bool "Module versioning support"
  735. depends on MODULES
  736. help
  737. Usually, you have to use modules compiled with your kernel.
  738. Saying Y here makes it sometimes possible to use modules
  739. compiled for different kernels, by adding enough information
  740. to the modules to (hopefully) spot any changes which would
  741. make them incompatible with the kernel you are running. If
  742. unsure, say N.
  743. config MODULE_SRCVERSION_ALL
  744. bool "Source checksum for all modules"
  745. depends on MODULES
  746. help
  747. Modules which contain a MODULE_VERSION get an extra "srcversion"
  748. field inserted into their modinfo section, which contains a
  749. sum of the source files which made it. This helps maintainers
  750. see exactly which source was used to build a module (since
  751. others sometimes change the module source without updating
  752. the version). With this option, such a "srcversion" field
  753. will be created for all modules. If unsure, say N.
  754. config KMOD
  755. bool "Automatic kernel module loading"
  756. depends on MODULES
  757. help
  758. Normally when you have selected some parts of the kernel to
  759. be created as kernel modules, you must load them (using the
  760. "modprobe" command) before you can use them. If you say Y
  761. here, some parts of the kernel will be able to load modules
  762. automatically: when a part of the kernel needs a module, it
  763. runs modprobe with the appropriate arguments, thereby
  764. loading the module if it is available. If unsure, say Y.
  765. config STOP_MACHINE
  766. bool
  767. default y
  768. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  769. help
  770. Need stop_machine() primitive.
  771. source "block/Kconfig"
  772. config PREEMPT_NOTIFIERS
  773. bool
  774. config CLASSIC_RCU
  775. def_bool !PREEMPT_RCU
  776. help
  777. This option selects the classic RCU implementation that is
  778. designed for best read-side performance on non-realtime
  779. systems. Classic RCU is the default. Note that the
  780. PREEMPT_RCU symbol is used to select/deselect this option.