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 drivers that have been replaced by something else, and/or are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