Kconfig 47 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. config CONSTRUCTORS
  17. bool
  18. depends on !UML
  19. config HAVE_IRQ_WORK
  20. bool
  21. config IRQ_WORK
  22. bool
  23. depends on HAVE_IRQ_WORK
  24. menu "General setup"
  25. config EXPERIMENTAL
  26. bool "Prompt for development and/or incomplete code/drivers"
  27. ---help---
  28. Some of the various things that Linux supports (such as network
  29. drivers, file systems, network protocols, etc.) can be in a state
  30. of development where the functionality, stability, or the level of
  31. testing is not yet high enough for general use. This is usually
  32. known as the "alpha-test" phase among developers. If a feature is
  33. currently in alpha-test, then the developers usually discourage
  34. uninformed widespread use of this feature by the general public to
  35. avoid "Why doesn't this work?" type mail messages. However, active
  36. testing and use of these systems is welcomed. Just be aware that it
  37. may not meet the normal level of reliability or it may fail to work
  38. in some special cases. Detailed bug reports from people familiar
  39. with the kernel internals are usually welcomed by the developers
  40. (before submitting bug reports, please read the documents
  41. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  42. <file:Documentation/BUG-HUNTING>, and
  43. <file:Documentation/oops-tracing.txt> in the kernel source).
  44. This option will also make obsoleted drivers available. These are
  45. drivers that have been replaced by something else, and/or are
  46. scheduled to be removed in a future kernel release.
  47. Unless you intend to help test and develop a feature or driver that
  48. falls into this category, or you have a situation that requires
  49. using these features, you should probably say N here, which will
  50. cause the configurator to present you with fewer choices. If
  51. you say Y here, you will be offered the choice of using features or
  52. drivers that are currently considered to be in the alpha-test phase.
  53. config BROKEN
  54. bool
  55. config BROKEN_ON_SMP
  56. bool
  57. depends on BROKEN || !SMP
  58. default y
  59. config INIT_ENV_ARG_LIMIT
  60. int
  61. default 32 if !UML
  62. default 128 if UML
  63. help
  64. Maximum of each of the number of arguments and environment
  65. variables passed to init from the kernel command line.
  66. config CROSS_COMPILE
  67. string "Cross-compiler tool prefix"
  68. help
  69. Same as running 'make CROSS_COMPILE=prefix-' but stored for
  70. default make runs in this kernel build directory. You don't
  71. need to set this unless you want the configured kernel build
  72. directory to select the cross-compiler automatically.
  73. config LOCALVERSION
  74. string "Local version - append to kernel release"
  75. help
  76. Append an extra string to the end of your kernel version.
  77. This will show up when you type uname, for example.
  78. The string you set here will be appended after the contents of
  79. any files with a filename matching localversion* in your
  80. object and source tree, in that order. Your total string can
  81. be a maximum of 64 characters.
  82. config LOCALVERSION_AUTO
  83. bool "Automatically append version information to the version string"
  84. default y
  85. help
  86. This will try to automatically determine if the current tree is a
  87. release tree by looking for git tags that belong to the current
  88. top of tree revision.
  89. A string of the format -gxxxxxxxx will be added to the localversion
  90. if a git-based tree is found. The string generated by this will be
  91. appended after any matching localversion* files, and after the value
  92. set in CONFIG_LOCALVERSION.
  93. (The actual string used here is the first eight characters produced
  94. by running the command:
  95. $ git rev-parse --verify HEAD
  96. which is done within the script "scripts/setlocalversion".)
  97. config HAVE_KERNEL_GZIP
  98. bool
  99. config HAVE_KERNEL_BZIP2
  100. bool
  101. config HAVE_KERNEL_LZMA
  102. bool
  103. config HAVE_KERNEL_XZ
  104. bool
  105. config HAVE_KERNEL_LZO
  106. bool
  107. config HAVE_KERNEL_LZ4
  108. bool
  109. choice
  110. prompt "Kernel compression mode"
  111. default KERNEL_GZIP
  112. depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
  113. help
  114. The linux kernel is a kind of self-extracting executable.
  115. Several compression algorithms are available, which differ
  116. in efficiency, compression and decompression speed.
  117. Compression speed is only relevant when building a kernel.
  118. Decompression speed is relevant at each boot.
  119. If you have any problems with bzip2 or lzma compressed
  120. kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
  121. version of this functionality (bzip2 only), for 2.4, was
  122. supplied by Christian Ludwig)
  123. High compression options are mostly useful for users, who
  124. are low on disk space (embedded systems), but for whom ram
  125. size matters less.
  126. If in doubt, select 'gzip'
  127. config KERNEL_GZIP
  128. bool "Gzip"
  129. depends on HAVE_KERNEL_GZIP
  130. help
  131. The old and tried gzip compression. It provides a good balance
  132. between compression ratio and decompression speed.
  133. config KERNEL_BZIP2
  134. bool "Bzip2"
  135. depends on HAVE_KERNEL_BZIP2
  136. help
  137. Its compression ratio and speed is intermediate.
  138. Decompression speed is slowest among the three. The kernel
  139. size is about 10% smaller with bzip2, in comparison to gzip.
  140. Bzip2 uses a large amount of memory. For modern kernels you
  141. will need at least 8MB RAM or more for booting.
  142. config KERNEL_LZMA
  143. bool "LZMA"
  144. depends on HAVE_KERNEL_LZMA
  145. help
  146. The most recent compression algorithm.
  147. Its ratio is best, decompression speed is between the other
  148. two. Compression is slowest. The kernel size is about 33%
  149. smaller with LZMA in comparison to gzip.
  150. config KERNEL_XZ
  151. bool "XZ"
  152. depends on HAVE_KERNEL_XZ
  153. help
  154. XZ uses the LZMA2 algorithm and instruction set specific
  155. BCJ filters which can improve compression ratio of executable
  156. code. The size of the kernel is about 30% smaller with XZ in
  157. comparison to gzip. On architectures for which there is a BCJ
  158. filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
  159. will create a few percent smaller kernel than plain LZMA.
  160. The speed is about the same as with LZMA: The decompression
  161. speed of XZ is better than that of bzip2 but worse than gzip
  162. and LZO. Compression is slow.
  163. config KERNEL_LZO
  164. bool "LZO"
  165. depends on HAVE_KERNEL_LZO
  166. help
  167. Its compression ratio is the poorest among the 4. The kernel
  168. size is about 10% bigger than gzip; however its speed
  169. (both compression and decompression) is the fastest.
  170. config KERNEL_LZ4
  171. bool "LZ4"
  172. depends on HAVE_KERNEL_LZ4
  173. help
  174. LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
  175. A preliminary version of LZ4 de/compression tool is available at
  176. <https://code.google.com/p/lz4/>.
  177. Its compression ratio is worse than LZO. The size of the kernel
  178. is about 8% bigger than LZO. But the decompression speed is
  179. faster than LZO.
  180. endchoice
  181. config DEFAULT_HOSTNAME
  182. string "Default hostname"
  183. default "(none)"
  184. help
  185. This option determines the default system hostname before userspace
  186. calls sethostname(2). The kernel traditionally uses "(none)" here,
  187. but you may wish to use a different default here to make a minimal
  188. system more usable with less configuration.
  189. config SWAP
  190. bool "Support for paging of anonymous memory (swap)"
  191. depends on MMU && BLOCK
  192. default y
  193. help
  194. This option allows you to choose whether you want to have support
  195. for so called swap devices or swap files in your kernel that are
  196. used to provide more virtual memory than the actual RAM present
  197. in your computer. If unsure say Y.
  198. config SYSVIPC
  199. bool "System V IPC"
  200. ---help---
  201. Inter Process Communication is a suite of library functions and
  202. system calls which let processes (running programs) synchronize and
  203. exchange information. It is generally considered to be a good thing,
  204. and some programs won't run unless you say Y here. In particular, if
  205. you want to run the DOS emulator dosemu under Linux (read the
  206. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  207. you'll need to say Y here.
  208. You can find documentation about IPC with "info ipc" and also in
  209. section 6.4 of the Linux Programmer's Guide, available from
  210. <http://www.tldp.org/guides.html>.
  211. config SYSVIPC_SYSCTL
  212. bool
  213. depends on SYSVIPC
  214. depends on SYSCTL
  215. default y
  216. config POSIX_MQUEUE
  217. bool "POSIX Message Queues"
  218. depends on NET && EXPERIMENTAL
  219. ---help---
  220. POSIX variant of message queues is a part of IPC. In POSIX message
  221. queues every message has a priority which decides about succession
  222. of receiving it by a process. If you want to compile and run
  223. programs written e.g. for Solaris with use of its POSIX message
  224. queues (functions mq_*) say Y here.
  225. POSIX message queues are visible as a filesystem called 'mqueue'
  226. and can be mounted somewhere if you want to do filesystem
  227. operations on message queues.
  228. If unsure, say Y.
  229. config POSIX_MQUEUE_SYSCTL
  230. bool
  231. depends on POSIX_MQUEUE
  232. depends on SYSCTL
  233. default y
  234. config BSD_PROCESS_ACCT
  235. bool "BSD Process Accounting"
  236. help
  237. If you say Y here, a user level program will be able to instruct the
  238. kernel (via a special system call) to write process accounting
  239. information to a file: whenever a process exits, information about
  240. that process will be appended to the file by the kernel. The
  241. information includes things such as creation time, owning user,
  242. command name, memory usage, controlling terminal etc. (the complete
  243. list is in the struct acct in <file:include/linux/acct.h>). It is
  244. up to the user level program to do useful things with this
  245. information. This is generally a good idea, so say Y.
  246. config BSD_PROCESS_ACCT_V3
  247. bool "BSD Process Accounting version 3 file format"
  248. depends on BSD_PROCESS_ACCT
  249. default n
  250. help
  251. If you say Y here, the process accounting information is written
  252. in a new file format that also logs the process IDs of each
  253. process and it's parent. Note that this file format is incompatible
  254. with previous v0/v1/v2 file formats, so you will need updated tools
  255. for processing it. A preliminary version of these tools is available
  256. at <http://www.gnu.org/software/acct/>.
  257. config FHANDLE
  258. bool "open by fhandle syscalls"
  259. select EXPORTFS
  260. help
  261. If you say Y here, a user level program will be able to map
  262. file names to handle and then later use the handle for
  263. different file system operations. This is useful in implementing
  264. userspace file servers, which now track files using handles instead
  265. of names. The handle would remain the same even if file names
  266. get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
  267. syscalls.
  268. config TASKSTATS
  269. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  270. depends on NET
  271. default n
  272. help
  273. Export selected statistics for tasks/processes through the
  274. generic netlink interface. Unlike BSD process accounting, the
  275. statistics are available during the lifetime of tasks/processes as
  276. responses to commands. Like BSD accounting, they are sent to user
  277. space on task exit.
  278. Say N if unsure.
  279. config TASK_DELAY_ACCT
  280. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  281. depends on TASKSTATS
  282. help
  283. Collect information on time spent by a task waiting for system
  284. resources like cpu, synchronous block I/O completion and swapping
  285. in pages. Such statistics can help in setting a task's priorities
  286. relative to other tasks for cpu, io, rss limits etc.
  287. Say N if unsure.
  288. config TASK_XACCT
  289. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  290. depends on TASKSTATS
  291. help
  292. Collect extended task accounting data and send the data
  293. to userland for processing over the taskstats interface.
  294. Say N if unsure.
  295. config TASK_IO_ACCOUNTING
  296. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  297. depends on TASK_XACCT
  298. help
  299. Collect information on the number of bytes of storage I/O which this
  300. task has caused.
  301. Say N if unsure.
  302. config AUDIT
  303. bool "Auditing support"
  304. depends on NET
  305. help
  306. Enable auditing infrastructure that can be used with another
  307. kernel subsystem, such as SELinux (which requires this for
  308. logging of avc messages output). Does not do system-call
  309. auditing without CONFIG_AUDITSYSCALL.
  310. config AUDITSYSCALL
  311. bool "Enable system-call auditing support"
  312. depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
  313. default y if SECURITY_SELINUX
  314. help
  315. Enable low-overhead system-call auditing infrastructure that
  316. can be used independently or with another kernel subsystem,
  317. such as SELinux.
  318. config AUDIT_WATCH
  319. def_bool y
  320. depends on AUDITSYSCALL
  321. select FSNOTIFY
  322. config AUDIT_TREE
  323. def_bool y
  324. depends on AUDITSYSCALL
  325. select FSNOTIFY
  326. config AUDIT_LOGINUID_IMMUTABLE
  327. bool "Make audit loginuid immutable"
  328. depends on AUDIT
  329. help
  330. The config option toggles if a task setting its loginuid requires
  331. CAP_SYS_AUDITCONTROL or if that task should require no special permissions
  332. but should instead only allow setting its loginuid if it was never
  333. previously set. On systems which use systemd or a similar central
  334. process to restart login services this should be set to true. On older
  335. systems in which an admin would typically have to directly stop and
  336. start processes this should be set to false. Setting this to true allows
  337. one to drop potentially dangerous capabilites from the login tasks,
  338. but may not be backwards compatible with older init systems.
  339. source "kernel/irq/Kconfig"
  340. menu "RCU Subsystem"
  341. choice
  342. prompt "RCU Implementation"
  343. default TREE_RCU
  344. config TREE_RCU
  345. bool "Tree-based hierarchical RCU"
  346. depends on !PREEMPT && SMP
  347. help
  348. This option selects the RCU implementation that is
  349. designed for very large SMP system with hundreds or
  350. thousands of CPUs. It also scales down nicely to
  351. smaller systems.
  352. config TREE_PREEMPT_RCU
  353. bool "Preemptible tree-based hierarchical RCU"
  354. depends on PREEMPT && SMP
  355. help
  356. This option selects the RCU implementation that is
  357. designed for very large SMP systems with hundreds or
  358. thousands of CPUs, but for which real-time response
  359. is also required. It also scales down nicely to
  360. smaller systems.
  361. config TINY_RCU
  362. bool "UP-only small-memory-footprint RCU"
  363. depends on !PREEMPT && !SMP
  364. help
  365. This option selects the RCU implementation that is
  366. designed for UP systems from which real-time response
  367. is not required. This option greatly reduces the
  368. memory footprint of RCU.
  369. config TINY_PREEMPT_RCU
  370. bool "Preemptible UP-only small-memory-footprint RCU"
  371. depends on PREEMPT && !SMP
  372. help
  373. This option selects the RCU implementation that is designed
  374. for real-time UP systems. This option greatly reduces the
  375. memory footprint of RCU.
  376. endchoice
  377. config PREEMPT_RCU
  378. def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
  379. help
  380. This option enables preemptible-RCU code that is common between
  381. the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
  382. config RCU_FANOUT
  383. int "Tree-based hierarchical RCU fanout value"
  384. range 2 64 if 64BIT
  385. range 2 32 if !64BIT
  386. depends on TREE_RCU || TREE_PREEMPT_RCU
  387. default 64 if 64BIT
  388. default 32 if !64BIT
  389. help
  390. This option controls the fanout of hierarchical implementations
  391. of RCU, allowing RCU to work efficiently on machines with
  392. large numbers of CPUs. This value must be at least the fourth
  393. root of NR_CPUS, which allows NR_CPUS to be insanely large.
  394. The default value of RCU_FANOUT should be used for production
  395. systems, but if you are stress-testing the RCU implementation
  396. itself, small RCU_FANOUT values allow you to test large-system
  397. code paths on small(er) systems.
  398. Select a specific number if testing RCU itself.
  399. Take the default if unsure.
  400. config RCU_FANOUT_EXACT
  401. bool "Disable tree-based hierarchical RCU auto-balancing"
  402. depends on TREE_RCU || TREE_PREEMPT_RCU
  403. default n
  404. help
  405. This option forces use of the exact RCU_FANOUT value specified,
  406. regardless of imbalances in the hierarchy. This is useful for
  407. testing RCU itself, and might one day be useful on systems with
  408. strong NUMA behavior.
  409. Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
  410. Say N if unsure.
  411. config RCU_FAST_NO_HZ
  412. bool "Accelerate last non-dyntick-idle CPU's grace periods"
  413. depends on NO_HZ && SMP && !SEC_FACTORY
  414. default n
  415. help
  416. This option causes RCU to attempt to accelerate grace periods
  417. in order to allow CPUs to enter dynticks-idle state more
  418. quickly. On the other hand, this option increases the overhead
  419. of the dynticks-idle checking, particularly on systems with
  420. large numbers of CPUs.
  421. Say Y if energy efficiency is critically important, particularly
  422. if you have relatively few CPUs.
  423. Say N if you are unsure.
  424. config RCU_FAST_NO_HZ_OFF_AT_BOOT
  425. bool "turn off rcu_fast_no_hz concept at boot time"
  426. depends on RCU_FAST_NO_HZ
  427. default n
  428. config TREE_RCU_TRACE
  429. def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
  430. select DEBUG_FS
  431. help
  432. This option provides tracing for the TREE_RCU and
  433. TREE_PREEMPT_RCU implementations, permitting Makefile to
  434. trivially select kernel/rcutree_trace.c.
  435. config RCU_BOOST
  436. bool "Enable RCU priority boosting"
  437. depends on RT_MUTEXES && PREEMPT_RCU
  438. default n
  439. help
  440. This option boosts the priority of preempted RCU readers that
  441. block the current preemptible RCU grace period for too long.
  442. This option also prevents heavy loads from blocking RCU
  443. callback invocation for all flavors of RCU.
  444. Say Y here if you are working with real-time apps or heavy loads
  445. Say N here if you are unsure.
  446. config RCU_BOOST_PRIO
  447. int "Real-time priority to boost RCU readers to"
  448. range 1 99
  449. depends on RCU_BOOST
  450. default 1
  451. help
  452. This option specifies the real-time priority to which preempted
  453. RCU readers are to be boosted. If you are working with CPU-bound
  454. real-time applications, you should specify a priority higher then
  455. the highest-priority CPU-bound application.
  456. Specify the real-time priority, or take the default if unsure.
  457. config RCU_BOOST_DELAY
  458. int "Milliseconds to delay boosting after RCU grace-period start"
  459. range 0 3000
  460. depends on RCU_BOOST
  461. default 500
  462. help
  463. This option specifies the time to wait after the beginning of
  464. a given grace period before priority-boosting preempted RCU
  465. readers blocking that grace period. Note that any RCU reader
  466. blocking an expedited RCU grace period is boosted immediately.
  467. Accept the default if unsure.
  468. endmenu # "RCU Subsystem"
  469. config IKCONFIG
  470. tristate "Kernel .config support"
  471. ---help---
  472. This option enables the complete Linux kernel ".config" file
  473. contents to be saved in the kernel. It provides documentation
  474. of which kernel options are used in a running kernel or in an
  475. on-disk kernel. This information can be extracted from the kernel
  476. image file with the script scripts/extract-ikconfig and used as
  477. input to rebuild the current kernel or to build another kernel.
  478. It can also be extracted from a running kernel by reading
  479. /proc/config.gz if enabled (below).
  480. config IKCONFIG_PROC
  481. bool "Enable access to .config through /proc/config.gz"
  482. depends on IKCONFIG && PROC_FS
  483. ---help---
  484. This option enables access to the kernel configuration file
  485. through /proc/config.gz.
  486. config LOG_BUF_SHIFT
  487. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  488. range 12 21
  489. default 17
  490. depends on PRINTK
  491. help
  492. Select kernel log buffer size as a power of 2.
  493. Examples:
  494. 17 => 128 KB
  495. 16 => 64 KB
  496. 15 => 32 KB
  497. 14 => 16 KB
  498. 13 => 8 KB
  499. 12 => 4 KB
  500. #
  501. # Architectures with an unreliable sched_clock() should select this:
  502. #
  503. config HAVE_UNSTABLE_SCHED_CLOCK
  504. bool
  505. config GENERIC_SCHED_CLOCK
  506. bool
  507. menuconfig CGROUPS
  508. boolean "Control Group support"
  509. depends on EVENTFD
  510. help
  511. This option adds support for grouping sets of processes together, for
  512. use with process control subsystems such as Cpusets, CFS, memory
  513. controls or device isolation.
  514. See
  515. - Documentation/scheduler/sched-design-CFS.txt (CFS)
  516. - Documentation/cgroups/ (features for grouping, isolation
  517. and resource control)
  518. Say N if unsure.
  519. if CGROUPS
  520. config CGROUP_DEBUG
  521. bool "Example debug cgroup subsystem"
  522. default n
  523. help
  524. This option enables a simple cgroup subsystem that
  525. exports useful debugging information about the cgroups
  526. framework.
  527. Say N if unsure.
  528. config CGROUP_FREEZER
  529. bool "Freezer cgroup subsystem"
  530. help
  531. Provides a way to freeze and unfreeze all tasks in a
  532. cgroup.
  533. config CGROUP_DEVICE
  534. bool "Device controller for cgroups"
  535. help
  536. Provides a cgroup implementing whitelists for devices which
  537. a process in the cgroup can mknod or open.
  538. config CPUSETS
  539. bool "Cpuset support"
  540. help
  541. This option will let you create and manage CPUSETs which
  542. allow dynamically partitioning a system into sets of CPUs and
  543. Memory Nodes and assigning tasks to run only within those sets.
  544. This is primarily useful on large SMP or NUMA systems.
  545. Say N if unsure.
  546. config PROC_PID_CPUSET
  547. bool "Include legacy /proc/<pid>/cpuset file"
  548. depends on CPUSETS
  549. default y
  550. config CGROUP_CPUACCT
  551. bool "Simple CPU accounting cgroup subsystem"
  552. help
  553. Provides a simple Resource Controller for monitoring the
  554. total CPU consumed by the tasks in a cgroup.
  555. config RESOURCE_COUNTERS
  556. bool "Resource counters"
  557. help
  558. This option enables controller independent resource accounting
  559. infrastructure that works with cgroups.
  560. config CGROUP_MEM_RES_CTLR
  561. bool "Memory Resource Controller for Control Groups"
  562. depends on RESOURCE_COUNTERS
  563. select MM_OWNER
  564. help
  565. Provides a memory resource controller that manages both anonymous
  566. memory and page cache. (See Documentation/cgroups/memory.txt)
  567. Note that setting this option increases fixed memory overhead
  568. associated with each page of memory in the system. By this,
  569. 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
  570. usage tracking struct at boot. Total amount of this is printed out
  571. at boot.
  572. Only enable when you're ok with these trade offs and really
  573. sure you need the memory resource controller. Even when you enable
  574. this, you can set "cgroup_disable=memory" at your boot option to
  575. disable memory resource controller and you can avoid overheads.
  576. (and lose benefits of memory resource controller)
  577. This config option also selects MM_OWNER config option, which
  578. could in turn add some fork/exit overhead.
  579. config CGROUP_MEM_RES_CTLR_SWAP
  580. bool "Memory Resource Controller Swap Extension"
  581. depends on CGROUP_MEM_RES_CTLR && SWAP
  582. help
  583. Add swap management feature to memory resource controller. When you
  584. enable this, you can limit mem+swap usage per cgroup. In other words,
  585. when you disable this, memory resource controller has no cares to
  586. usage of swap...a process can exhaust all of the swap. This extension
  587. is useful when you want to avoid exhaustion swap but this itself
  588. adds more overheads and consumes memory for remembering information.
  589. Especially if you use 32bit system or small memory system, please
  590. be careful about enabling this. When memory resource controller
  591. is disabled by boot option, this will be automatically disabled and
  592. there will be no overhead from this. Even when you set this config=y,
  593. if boot option "swapaccount=0" is set, swap will not be accounted.
  594. Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
  595. size is 4096bytes, 512k per 1Gbytes of swap.
  596. config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  597. bool "Memory Resource Controller Swap Extension enabled by default"
  598. depends on CGROUP_MEM_RES_CTLR_SWAP
  599. default y
  600. help
  601. Memory Resource Controller Swap Extension comes with its price in
  602. a bigger memory consumption. General purpose distribution kernels
  603. which want to enable the feature but keep it disabled by default
  604. and let the user enable it by swapaccount boot command line
  605. parameter should have this option unselected.
  606. For those who want to have the feature enabled by default should
  607. select this option (if, for some reason, they need to disable it
  608. then swapaccount=0 does the trick).
  609. config CGROUP_MEM_RES_CTLR_KMEM
  610. bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
  611. depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
  612. default n
  613. help
  614. The Kernel Memory extension for Memory Resource Controller can limit
  615. the amount of memory used by kernel objects in the system. Those are
  616. fundamentally different from the entities handled by the standard
  617. Memory Controller, which are page-based, and can be swapped. Users of
  618. the kmem extension can use it to guarantee that no group of processes
  619. will ever exhaust kernel resources alone.
  620. config CGROUP_PERF
  621. bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
  622. depends on PERF_EVENTS && CGROUPS
  623. help
  624. This option extends the per-cpu mode to restrict monitoring to
  625. threads which belong to the cgroup specified and run on the
  626. designated cpu.
  627. Say N if unsure.
  628. menuconfig CGROUP_SCHED
  629. bool "Group CPU scheduler"
  630. default n
  631. help
  632. This feature lets CPU scheduler recognize task groups and control CPU
  633. bandwidth allocation to such task groups. It uses cgroups to group
  634. tasks.
  635. if CGROUP_SCHED
  636. config FAIR_GROUP_SCHED
  637. bool "Group scheduling for SCHED_OTHER"
  638. depends on CGROUP_SCHED
  639. default CGROUP_SCHED
  640. config CFS_BANDWIDTH
  641. bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
  642. depends on EXPERIMENTAL
  643. depends on FAIR_GROUP_SCHED
  644. default n
  645. help
  646. This option allows users to define CPU bandwidth rates (limits) for
  647. tasks running within the fair group scheduler. Groups with no limit
  648. set are considered to be unconstrained and will run with no
  649. restriction.
  650. See tip/Documentation/scheduler/sched-bwc.txt for more information.
  651. config RT_GROUP_SCHED
  652. bool "Group scheduling for SCHED_RR/FIFO"
  653. depends on EXPERIMENTAL
  654. depends on CGROUP_SCHED
  655. default n
  656. help
  657. This feature lets you explicitly allocate real CPU bandwidth
  658. to task groups. If enabled, it will also make it impossible to
  659. schedule realtime tasks for non-root users until you allocate
  660. realtime bandwidth for them.
  661. See Documentation/scheduler/sched-rt-group.txt for more information.
  662. endif #CGROUP_SCHED
  663. config BLK_CGROUP
  664. tristate "Block IO controller"
  665. depends on BLOCK
  666. default n
  667. ---help---
  668. Generic block IO controller cgroup interface. This is the common
  669. cgroup interface which should be used by various IO controlling
  670. policies.
  671. Currently, CFQ IO scheduler uses it to recognize task groups and
  672. control disk bandwidth allocation (proportional time slice allocation)
  673. to such task groups. It is also used by bio throttling logic in
  674. block layer to implement upper limit in IO rates on a device.
  675. This option only enables generic Block IO controller infrastructure.
  676. One needs to also enable actual IO controlling logic/policy. For
  677. enabling proportional weight division of disk bandwidth in CFQ, set
  678. CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
  679. CONFIG_BLK_DEV_THROTTLING=y.
  680. See Documentation/cgroups/blkio-controller.txt for more information.
  681. config DEBUG_BLK_CGROUP
  682. bool "Enable Block IO controller debugging"
  683. depends on BLK_CGROUP
  684. default n
  685. ---help---
  686. Enable some debugging help. Currently it exports additional stat
  687. files in a cgroup which can be useful for debugging.
  688. endif # CGROUPS
  689. config CHECKPOINT_RESTORE
  690. bool "Checkpoint/restore support" if EXPERT
  691. default n
  692. help
  693. Enables additional kernel features in a sake of checkpoint/restore.
  694. In particular it adds auxiliary prctl codes to setup process text,
  695. data and heap segment sizes, and a few additional /proc filesystem
  696. entries.
  697. If unsure, say N here.
  698. menuconfig NAMESPACES
  699. bool "Namespaces support" if EXPERT
  700. default !EXPERT
  701. help
  702. Provides the way to make tasks work with different objects using
  703. the same id. For example same IPC id may refer to different objects
  704. or same user id or pid may refer to different tasks when used in
  705. different namespaces.
  706. if NAMESPACES
  707. config UTS_NS
  708. bool "UTS namespace"
  709. default y
  710. help
  711. In this namespace tasks see different info provided with the
  712. uname() system call
  713. config IPC_NS
  714. bool "IPC namespace"
  715. depends on (SYSVIPC || POSIX_MQUEUE)
  716. default y
  717. help
  718. In this namespace tasks work with IPC ids which correspond to
  719. different IPC objects in different namespaces.
  720. config USER_NS
  721. bool "User namespace (EXPERIMENTAL)"
  722. depends on EXPERIMENTAL
  723. default y
  724. help
  725. This allows containers, i.e. vservers, to use user namespaces
  726. to provide different user info for different servers.
  727. When user namespaces are enabled in the kernel it is
  728. recommended that the MEMCG and MEMCG_KMEM options also be
  729. enabled and that user-space use the memory control groups to
  730. limit the amount of memory a memory unprivileged users can
  731. use.
  732. If unsure, say N.
  733. config PID_NS
  734. bool "PID Namespaces"
  735. default y
  736. help
  737. Support process id namespaces. This allows having multiple
  738. processes with the same pid as long as they are in different
  739. pid namespaces. This is a building block of containers.
  740. config NET_NS
  741. bool "Network namespace"
  742. depends on NET
  743. default y
  744. help
  745. Allow user space to create what appear to be multiple instances
  746. of the network stack.
  747. endif # NAMESPACES
  748. config SCHED_AUTOGROUP
  749. bool "Automatic process group scheduling"
  750. select EVENTFD
  751. select CGROUPS
  752. select CGROUP_SCHED
  753. select FAIR_GROUP_SCHED
  754. help
  755. This option optimizes the scheduler for common desktop workloads by
  756. automatically creating and populating task groups. This separation
  757. of workloads isolates aggressive CPU burners (like build jobs) from
  758. desktop applications. Task group autogeneration is currently based
  759. upon task session.
  760. config MM_OWNER
  761. bool
  762. config SYSFS_DEPRECATED
  763. bool "Enable deprecated sysfs features to support old userspace tools"
  764. depends on SYSFS
  765. default n
  766. help
  767. This option adds code that switches the layout of the "block" class
  768. devices, to not show up in /sys/class/block/, but only in
  769. /sys/block/.
  770. This switch is only active when the sysfs.deprecated=1 boot option is
  771. passed or the SYSFS_DEPRECATED_V2 option is set.
  772. This option allows new kernels to run on old distributions and tools,
  773. which might get confused by /sys/class/block/. Since 2007/2008 all
  774. major distributions and tools handle this just fine.
  775. Recent distributions and userspace tools after 2009/2010 depend on
  776. the existence of /sys/class/block/, and will not work with this
  777. option enabled.
  778. Only if you are using a new kernel on an old distribution, you might
  779. need to say Y here.
  780. config SYSFS_DEPRECATED_V2
  781. bool "Enable deprecated sysfs features by default"
  782. default n
  783. depends on SYSFS
  784. depends on SYSFS_DEPRECATED
  785. help
  786. Enable deprecated sysfs by default.
  787. See the CONFIG_SYSFS_DEPRECATED option for more details about this
  788. option.
  789. Only if you are using a new kernel on an old distribution, you might
  790. need to say Y here. Even then, odds are you would not need it
  791. enabled, you can always pass the boot option if absolutely necessary.
  792. config RELAY
  793. bool "Kernel->user space relay support (formerly relayfs)"
  794. help
  795. This option enables support for relay interface support in
  796. certain file systems (such as debugfs).
  797. It is designed to provide an efficient mechanism for tools and
  798. facilities to relay large amounts of data from kernel space to
  799. user space.
  800. If unsure, say N.
  801. config BLK_DEV_INITRD
  802. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  803. depends on BROKEN || !FRV
  804. help
  805. The initial RAM filesystem is a ramfs which is loaded by the
  806. boot loader (loadlin or lilo) and that is mounted as root
  807. before the normal boot procedure. It is typically used to
  808. load modules needed to mount the "real" root file system,
  809. etc. See <file:Documentation/initrd.txt> for details.
  810. If RAM disk support (BLK_DEV_RAM) is also included, this
  811. also enables initial RAM disk (initrd) support and adds
  812. 15 Kbytes (more on some other architectures) to the kernel size.
  813. If unsure say Y.
  814. if BLK_DEV_INITRD
  815. source "usr/Kconfig"
  816. endif
  817. config CC_OPTIMIZE_FOR_SIZE
  818. bool "Optimize for size"
  819. help
  820. Enabling this option will pass "-Os" instead of "-O2" to gcc
  821. resulting in a smaller kernel.
  822. If unsure, say Y.
  823. config SYSCTL
  824. bool
  825. config ANON_INODES
  826. bool
  827. config PANIC_TIMEOUT
  828. int "Default panic timeout"
  829. default 0
  830. help
  831. Set default panic timeout.
  832. menuconfig EXPERT
  833. bool "Configure standard kernel features (expert users)"
  834. # Unhide debug options, to make the on-by-default options visible
  835. select DEBUG_KERNEL
  836. help
  837. This option allows certain base kernel options and settings
  838. to be disabled or tweaked. This is for specialized
  839. environments which can tolerate a "non-standard" kernel.
  840. Only use this if you really know what you are doing.
  841. config UID16
  842. bool "Enable 16-bit UID system calls" if EXPERT
  843. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
  844. default y
  845. help
  846. This enables the legacy 16-bit UID syscall wrappers.
  847. config SYSCTL_SYSCALL
  848. bool "Sysctl syscall support" if EXPERT
  849. depends on PROC_SYSCTL
  850. default n
  851. select SYSCTL
  852. ---help---
  853. sys_sysctl uses binary paths that have been found challenging
  854. to properly maintain and use. The interface in /proc/sys
  855. using paths with ascii names is now the primary path to this
  856. information.
  857. Almost nothing using the binary sysctl interface so if you are
  858. trying to save some space it is probably safe to disable this,
  859. making your kernel marginally smaller.
  860. If unsure say N here.
  861. config KALLSYMS
  862. bool "Load all symbols for debugging/ksymoops" if EXPERT
  863. default y
  864. help
  865. Say Y here to let the kernel print out symbolic crash information and
  866. symbolic stack backtraces. This increases the size of the kernel
  867. somewhat, as all symbols have to be loaded into the kernel image.
  868. config KALLSYMS_ALL
  869. bool "Include all symbols in kallsyms"
  870. depends on DEBUG_KERNEL && KALLSYMS
  871. help
  872. Normally kallsyms only contains the symbols of functions for nicer
  873. OOPS messages and backtraces (i.e., symbols from the text and inittext
  874. sections). This is sufficient for most cases. And only in very rare
  875. cases (e.g., when a debugger is used) all symbols are required (e.g.,
  876. names of variables from the data sections, etc).
  877. This option makes sure that all symbols are loaded into the kernel
  878. image (i.e., symbols from all sections) in cost of increased kernel
  879. size (depending on the kernel configuration, it may be 300KiB or
  880. something like this).
  881. Say N unless you really need all symbols.
  882. config HOTPLUG
  883. bool "Support for hot-pluggable devices" if EXPERT
  884. default y
  885. help
  886. This option is provided for the case where no hotplug or uevent
  887. capabilities is wanted by the kernel. You should only consider
  888. disabling this option for embedded systems that do not use modules, a
  889. dynamic /dev tree, or dynamic device discovery. Just say Y.
  890. config PRINTK
  891. default y
  892. bool "Enable support for printk" if EXPERT
  893. help
  894. This option enables normal printk support. Removing it
  895. eliminates most of the message strings from the kernel image
  896. and makes the kernel more or less silent. As this makes it
  897. very difficult to diagnose system problems, saying N here is
  898. strongly discouraged.
  899. config BUG
  900. bool "BUG() support" if EXPERT
  901. default y
  902. help
  903. Disabling this option eliminates support for BUG and WARN, reducing
  904. the size of your kernel image and potentially quietly ignoring
  905. numerous fatal conditions. You should only consider disabling this
  906. option for embedded systems with no facilities for reporting errors.
  907. Just say Y.
  908. config ELF_CORE
  909. default y
  910. bool "Enable ELF core dumps" if EXPERT
  911. help
  912. Enable support for generating core dumps. Disabling saves about 4k.
  913. config PCSPKR_PLATFORM
  914. bool "Enable PC-Speaker support" if EXPERT
  915. depends on HAVE_PCSPKR_PLATFORM
  916. select I8253_LOCK
  917. default y
  918. help
  919. This option allows to disable the internal PC-Speaker
  920. support, saving some memory.
  921. config HAVE_PCSPKR_PLATFORM
  922. bool
  923. config BASE_FULL
  924. default y
  925. bool "Enable full-sized data structures for core" if EXPERT
  926. help
  927. Disabling this option reduces the size of miscellaneous core
  928. kernel data structures. This saves memory on small machines,
  929. but may reduce performance.
  930. config FUTEX
  931. bool "Enable futex support" if EXPERT
  932. default y
  933. select RT_MUTEXES
  934. help
  935. Disabling this option will cause the kernel to be built without
  936. support for "fast userspace mutexes". The resulting kernel may not
  937. run glibc-based applications correctly.
  938. config EPOLL
  939. bool "Enable eventpoll support" if EXPERT
  940. default y
  941. select ANON_INODES
  942. help
  943. Disabling this option will cause the kernel to be built without
  944. support for epoll family of system calls.
  945. config SIGNALFD
  946. bool "Enable signalfd() system call" if EXPERT
  947. select ANON_INODES
  948. default y
  949. help
  950. Enable the signalfd() system call that allows to receive signals
  951. on a file descriptor.
  952. If unsure, say Y.
  953. config TIMERFD
  954. bool "Enable timerfd() system call" if EXPERT
  955. select ANON_INODES
  956. default y
  957. help
  958. Enable the timerfd() system call that allows to receive timer
  959. events on a file descriptor.
  960. If unsure, say Y.
  961. config EVENTFD
  962. bool "Enable eventfd() system call" if EXPERT
  963. select ANON_INODES
  964. default y
  965. help
  966. Enable the eventfd() system call that allows to receive both
  967. kernel notification (ie. KAIO) or userspace notifications.
  968. If unsure, say Y.
  969. config SHMEM
  970. bool "Use full shmem filesystem" if EXPERT
  971. default y
  972. depends on MMU
  973. help
  974. The shmem is an internal filesystem used to manage shared memory.
  975. It is backed by swap and manages resource limits. It is also exported
  976. to userspace as tmpfs if TMPFS is enabled. Disabling this
  977. option replaces shmem and tmpfs with the much simpler ramfs code,
  978. which may be appropriate on small systems without swap.
  979. config AIO
  980. bool "Enable AIO support" if EXPERT
  981. default y
  982. help
  983. This option enables POSIX asynchronous I/O which may by used
  984. by some high performance threaded applications. Disabling
  985. this option saves about 7k.
  986. config EMBEDDED
  987. bool "Embedded system"
  988. select EXPERT
  989. help
  990. This option should be enabled if compiling the kernel for
  991. an embedded system so certain expert options are available
  992. for configuration.
  993. config HAVE_PERF_EVENTS
  994. bool
  995. help
  996. See tools/perf/design.txt for details.
  997. config PERF_USE_VMALLOC
  998. bool
  999. help
  1000. See tools/perf/design.txt for details
  1001. menu "Kernel Performance Events And Counters"
  1002. config PERF_EVENTS
  1003. bool "Kernel performance events and counters"
  1004. default y if (PROFILING || PERF_COUNTERS)
  1005. depends on HAVE_PERF_EVENTS
  1006. select ANON_INODES
  1007. select IRQ_WORK
  1008. help
  1009. Enable kernel support for various performance events provided
  1010. by software and hardware.
  1011. Software events are supported either built-in or via the
  1012. use of generic tracepoints.
  1013. Most modern CPUs support performance events via performance
  1014. counter registers. These registers count the number of certain
  1015. types of hw events: such as instructions executed, cachemisses
  1016. suffered, or branches mis-predicted - without slowing down the
  1017. kernel or applications. These registers can also trigger interrupts
  1018. when a threshold number of events have passed - and can thus be
  1019. used to profile the code that runs on that CPU.
  1020. The Linux Performance Event subsystem provides an abstraction of
  1021. these software and hardware event capabilities, available via a
  1022. system call and used by the "perf" utility in tools/perf/. It
  1023. provides per task and per CPU counters, and it provides event
  1024. capabilities on top of those.
  1025. Say Y if unsure.
  1026. config PERF_COUNTERS
  1027. bool "Kernel performance counters (old config option)"
  1028. depends on HAVE_PERF_EVENTS
  1029. help
  1030. This config has been obsoleted by the PERF_EVENTS
  1031. config option - please see that one for details.
  1032. It has no effect on the kernel whether you enable
  1033. it or not, it is a compatibility placeholder.
  1034. Say N if unsure.
  1035. config DEBUG_PERF_USE_VMALLOC
  1036. default n
  1037. bool "Debug: use vmalloc to back perf mmap() buffers"
  1038. depends on PERF_EVENTS && DEBUG_KERNEL
  1039. select PERF_USE_VMALLOC
  1040. help
  1041. Use vmalloc memory to back perf mmap() buffers.
  1042. Mostly useful for debugging the vmalloc code on platforms
  1043. that don't require it.
  1044. Say N if unsure.
  1045. endmenu
  1046. config VM_EVENT_COUNTERS
  1047. default y
  1048. bool "Enable VM event counters for /proc/vmstat" if EXPERT
  1049. help
  1050. VM event counters are needed for event counts to be shown.
  1051. This option allows the disabling of the VM event counters
  1052. on EXPERT systems. /proc/vmstat will only show page counts
  1053. if VM event counters are disabled.
  1054. config PCI_QUIRKS
  1055. default y
  1056. bool "Enable PCI quirk workarounds" if EXPERT
  1057. depends on PCI
  1058. help
  1059. This enables workarounds for various PCI chipset
  1060. bugs/quirks. Disable this only if your target machine is
  1061. unaffected by PCI quirks.
  1062. config SLUB_DEBUG
  1063. default y
  1064. bool "Enable SLUB debugging support" if EXPERT
  1065. depends on SLUB && SYSFS
  1066. help
  1067. SLUB has extensive debug support features. Disabling these can
  1068. result in significant savings in code size. This also disables
  1069. SLUB sysfs support. /sys/slab will not exist and there will be
  1070. no support for cache validation etc.
  1071. config COMPAT_BRK
  1072. bool "Disable heap randomization"
  1073. default y
  1074. help
  1075. Randomizing heap placement makes heap exploits harder, but it
  1076. also breaks ancient binaries (including anything libc5 based).
  1077. This option changes the bootup default to heap randomization
  1078. disabled, and can be overridden at runtime by setting
  1079. /proc/sys/kernel/randomize_va_space to 2.
  1080. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  1081. choice
  1082. prompt "Choose SLAB allocator"
  1083. default SLUB
  1084. help
  1085. This option allows to select a slab allocator.
  1086. config SLAB
  1087. bool "SLAB"
  1088. help
  1089. The regular slab allocator that is established and known to work
  1090. well in all environments. It organizes cache hot objects in
  1091. per cpu and per node queues.
  1092. config SLUB
  1093. depends on BROKEN || NUMA || !DISCONTIGMEM
  1094. bool "SLUB (Unqueued Allocator)"
  1095. help
  1096. SLUB is a slab allocator that minimizes cache line usage
  1097. instead of managing queues of cached objects (SLAB approach).
  1098. Per cpu caching is realized using slabs of objects instead
  1099. of queues of objects. SLUB can use memory efficiently
  1100. and has enhanced diagnostics. SLUB is the default choice for
  1101. a slab allocator.
  1102. config SLOB
  1103. depends on EXPERT
  1104. bool "SLOB (Simple Allocator)"
  1105. help
  1106. SLOB replaces the stock allocator with a drastically simpler
  1107. allocator. SLOB is generally more space efficient but
  1108. does not perform as well on large systems.
  1109. endchoice
  1110. config MMAP_ALLOW_UNINITIALIZED
  1111. bool "Allow mmapped anonymous memory to be uninitialized"
  1112. depends on EXPERT && !MMU
  1113. default n
  1114. help
  1115. Normally, and according to the Linux spec, anonymous memory obtained
  1116. from mmap() has it's contents cleared before it is passed to
  1117. userspace. Enabling this config option allows you to request that
  1118. mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
  1119. providing a huge performance boost. If this option is not enabled,
  1120. then the flag will be ignored.
  1121. This is taken advantage of by uClibc's malloc(), and also by
  1122. ELF-FDPIC binfmt's brk and stack allocator.
  1123. Because of the obvious security issues, this option should only be
  1124. enabled on embedded devices where you control what is run in
  1125. userspace. Since that isn't generally a problem on no-MMU systems,
  1126. it is normally safe to say Y here.
  1127. See Documentation/nommu-mmap.txt for more information.
  1128. config DEFERRED_INITCALLS
  1129. bool "Deferred initcalls support"
  1130. default n
  1131. help
  1132. Say 'y' here to include support for deferred initcalls
  1133. config PROFILING
  1134. bool "Profiling support"
  1135. help
  1136. Say Y here to enable the extended profiling support mechanisms used
  1137. by profilers such as OProfile.
  1138. #
  1139. # Place an empty function call at each tracepoint site. Can be
  1140. # dynamically changed for a probe function.
  1141. #
  1142. config TRACEPOINTS
  1143. bool
  1144. source "arch/Kconfig"
  1145. endmenu # General setup
  1146. config HAVE_GENERIC_DMA_COHERENT
  1147. bool
  1148. default n
  1149. config SLABINFO
  1150. bool
  1151. depends on PROC_FS
  1152. depends on SLAB || SLUB_DEBUG
  1153. default y
  1154. config RT_MUTEXES
  1155. boolean
  1156. config BASE_SMALL
  1157. int
  1158. default 0 if BASE_FULL
  1159. default 1 if !BASE_FULL
  1160. menuconfig MODULES
  1161. bool "Enable loadable module support"
  1162. help
  1163. Kernel modules are small pieces of compiled code which can
  1164. be inserted in the running kernel, rather than being
  1165. permanently built into the kernel. You use the "modprobe"
  1166. tool to add (and sometimes remove) them. If you say Y here,
  1167. many parts of the kernel can be built as modules (by
  1168. answering M instead of Y where indicated): this is most
  1169. useful for infrequently used options which are not required
  1170. for booting. For more information, see the man pages for
  1171. modprobe, lsmod, modinfo, insmod and rmmod.
  1172. If you say Y here, you will need to run "make
  1173. modules_install" to put the modules under /lib/modules/
  1174. where modprobe can find them (you may need to be root to do
  1175. this).
  1176. If unsure, say Y.
  1177. if MODULES
  1178. config MODULE_FORCE_LOAD
  1179. bool "Forced module loading"
  1180. default n
  1181. help
  1182. Allow loading of modules without version information (ie. modprobe
  1183. --force). Forced module loading sets the 'F' (forced) taint flag and
  1184. is usually a really bad idea.
  1185. config MODULE_UNLOAD
  1186. bool "Module unloading"
  1187. help
  1188. Without this option you will not be able to unload any
  1189. modules (note that some modules may not be unloadable
  1190. anyway), which makes your kernel smaller, faster
  1191. and simpler. If unsure, say Y.
  1192. config MODULE_FORCE_UNLOAD
  1193. bool "Forced module unloading"
  1194. depends on MODULE_UNLOAD && EXPERIMENTAL
  1195. help
  1196. This option allows you to force a module to unload, even if the
  1197. kernel believes it is unsafe: the kernel will remove the module
  1198. without waiting for anyone to stop using it (using the -f option to
  1199. rmmod). This is mainly for kernel developers and desperate users.
  1200. If unsure, say N.
  1201. config MODVERSIONS
  1202. bool "Module versioning support"
  1203. help
  1204. Usually, you have to use modules compiled with your kernel.
  1205. Saying Y here makes it sometimes possible to use modules
  1206. compiled for different kernels, by adding enough information
  1207. to the modules to (hopefully) spot any changes which would
  1208. make them incompatible with the kernel you are running. If
  1209. unsure, say N.
  1210. config MODULE_SRCVERSION_ALL
  1211. bool "Source checksum for all modules"
  1212. help
  1213. Modules which contain a MODULE_VERSION get an extra "srcversion"
  1214. field inserted into their modinfo section, which contains a
  1215. sum of the source files which made it. This helps maintainers
  1216. see exactly which source was used to build a module (since
  1217. others sometimes change the module source without updating
  1218. the version). With this option, such a "srcversion" field
  1219. will be created for all modules. If unsure, say N.
  1220. endif # MODULES
  1221. config INIT_ALL_POSSIBLE
  1222. bool
  1223. help
  1224. Back when each arch used to define their own cpu_online_mask and
  1225. cpu_possible_mask, some of them chose to initialize cpu_possible_mask
  1226. with all 1s, and others with all 0s. When they were centralised,
  1227. it was better to provide this option than to break all the archs
  1228. and have several arch maintainers pursuing me down dark alleys.
  1229. config STOP_MACHINE
  1230. bool
  1231. default y
  1232. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  1233. help
  1234. Need stop_machine() primitive.
  1235. source "block/Kconfig"
  1236. config PREEMPT_NOTIFIERS
  1237. bool
  1238. config PADATA
  1239. depends on SMP
  1240. bool
  1241. source "kernel/Kconfig.locks"