Kconfig 43 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384
  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. default y
  20. config HAVE_IRQ_WORK
  21. bool
  22. config IRQ_WORK
  23. bool
  24. depends on HAVE_IRQ_WORK
  25. menu "General setup"
  26. config EXPERIMENTAL
  27. bool "Prompt for development and/or incomplete code/drivers"
  28. ---help---
  29. Some of the various things that Linux supports (such as network
  30. drivers, file systems, network protocols, etc.) can be in a state
  31. of development where the functionality, stability, or the level of
  32. testing is not yet high enough for general use. This is usually
  33. known as the "alpha-test" phase among developers. If a feature is
  34. currently in alpha-test, then the developers usually discourage
  35. uninformed widespread use of this feature by the general public to
  36. avoid "Why doesn't this work?" type mail messages. However, active
  37. testing and use of these systems is welcomed. Just be aware that it
  38. may not meet the normal level of reliability or it may fail to work
  39. in some special cases. Detailed bug reports from people familiar
  40. with the kernel internals are usually welcomed by the developers
  41. (before submitting bug reports, please read the documents
  42. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  43. <file:Documentation/BUG-HUNTING>, and
  44. <file:Documentation/oops-tracing.txt> in the kernel source).
  45. This option will also make obsoleted drivers available. These are
  46. drivers that have been replaced by something else, and/or are
  47. scheduled to be removed in a future kernel release.
  48. Unless you intend to help test and develop a feature or driver that
  49. falls into this category, or you have a situation that requires
  50. using these features, you should probably say N here, which will
  51. cause the configurator to present you with fewer choices. If
  52. you say Y here, you will be offered the choice of using features or
  53. drivers that are currently considered to be in the alpha-test phase.
  54. config BROKEN
  55. bool
  56. config BROKEN_ON_SMP
  57. bool
  58. depends on BROKEN || !SMP
  59. default y
  60. config LOCK_KERNEL
  61. bool
  62. depends on (SMP || PREEMPT) && BKL
  63. default y
  64. config INIT_ENV_ARG_LIMIT
  65. int
  66. default 32 if !UML
  67. default 128 if UML
  68. help
  69. Maximum of each of the number of arguments and environment
  70. variables passed to init from the kernel command line.
  71. config CROSS_COMPILE
  72. string "Cross-compiler tool prefix"
  73. help
  74. Same as running 'make CROSS_COMPILE=prefix-' but stored for
  75. default make runs in this kernel build directory. You don't
  76. need to set this unless you want the configured kernel build
  77. directory to select the cross-compiler automatically.
  78. config LOCALVERSION
  79. string "Local version - append to kernel release"
  80. help
  81. Append an extra string to the end of your kernel version.
  82. This will show up when you type uname, for example.
  83. The string you set here will be appended after the contents of
  84. any files with a filename matching localversion* in your
  85. object and source tree, in that order. Your total string can
  86. be a maximum of 64 characters.
  87. config LOCALVERSION_AUTO
  88. bool "Automatically append version information to the version string"
  89. default y
  90. help
  91. This will try to automatically determine if the current tree is a
  92. release tree by looking for git tags that belong to the current
  93. top of tree revision.
  94. A string of the format -gxxxxxxxx will be added to the localversion
  95. if a git-based tree is found. The string generated by this will be
  96. appended after any matching localversion* files, and after the value
  97. set in CONFIG_LOCALVERSION.
  98. (The actual string used here is the first eight characters produced
  99. by running the command:
  100. $ git rev-parse --verify HEAD
  101. which is done within the script "scripts/setlocalversion".)
  102. config HAVE_KERNEL_GZIP
  103. bool
  104. config HAVE_KERNEL_BZIP2
  105. bool
  106. config HAVE_KERNEL_LZMA
  107. bool
  108. config HAVE_KERNEL_XZ
  109. bool
  110. config HAVE_KERNEL_LZO
  111. bool
  112. choice
  113. prompt "Kernel compression mode"
  114. default KERNEL_GZIP
  115. depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
  116. help
  117. The linux kernel is a kind of self-extracting executable.
  118. Several compression algorithms are available, which differ
  119. in efficiency, compression and decompression speed.
  120. Compression speed is only relevant when building a kernel.
  121. Decompression speed is relevant at each boot.
  122. If you have any problems with bzip2 or lzma compressed
  123. kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
  124. version of this functionality (bzip2 only), for 2.4, was
  125. supplied by Christian Ludwig)
  126. High compression options are mostly useful for users, who
  127. are low on disk space (embedded systems), but for whom ram
  128. size matters less.
  129. If in doubt, select 'gzip'
  130. config KERNEL_GZIP
  131. bool "Gzip"
  132. depends on HAVE_KERNEL_GZIP
  133. help
  134. The old and tried gzip compression. It provides a good balance
  135. between compression ratio and decompression speed.
  136. config KERNEL_BZIP2
  137. bool "Bzip2"
  138. depends on HAVE_KERNEL_BZIP2
  139. help
  140. Its compression ratio and speed is intermediate.
  141. Decompression speed is slowest among the three. The kernel
  142. size is about 10% smaller with bzip2, in comparison to gzip.
  143. Bzip2 uses a large amount of memory. For modern kernels you
  144. will need at least 8MB RAM or more for booting.
  145. config KERNEL_LZMA
  146. bool "LZMA"
  147. depends on HAVE_KERNEL_LZMA
  148. help
  149. The most recent compression algorithm.
  150. Its ratio is best, decompression speed is between the other
  151. two. Compression is slowest. The kernel size is about 33%
  152. smaller with LZMA in comparison to gzip.
  153. config KERNEL_XZ
  154. bool "XZ"
  155. depends on HAVE_KERNEL_XZ
  156. help
  157. XZ uses the LZMA2 algorithm and instruction set specific
  158. BCJ filters which can improve compression ratio of executable
  159. code. The size of the kernel is about 30% smaller with XZ in
  160. comparison to gzip. On architectures for which there is a BCJ
  161. filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
  162. will create a few percent smaller kernel than plain LZMA.
  163. The speed is about the same as with LZMA: The decompression
  164. speed of XZ is better than that of bzip2 but worse than gzip
  165. and LZO. Compression is slow.
  166. config KERNEL_LZO
  167. bool "LZO"
  168. depends on HAVE_KERNEL_LZO
  169. help
  170. Its compression ratio is the poorest among the 4. The kernel
  171. size is about 10% bigger than gzip; however its speed
  172. (both compression and decompression) is the fastest.
  173. endchoice
  174. config SWAP
  175. bool "Support for paging of anonymous memory (swap)"
  176. depends on MMU && BLOCK
  177. default y
  178. help
  179. This option allows you to choose whether you want to have support
  180. for so called swap devices or swap files in your kernel that are
  181. used to provide more virtual memory than the actual RAM present
  182. in your computer. If unsure say Y.
  183. config SYSVIPC
  184. bool "System V IPC"
  185. ---help---
  186. Inter Process Communication is a suite of library functions and
  187. system calls which let processes (running programs) synchronize and
  188. exchange information. It is generally considered to be a good thing,
  189. and some programs won't run unless you say Y here. In particular, if
  190. you want to run the DOS emulator dosemu under Linux (read the
  191. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  192. you'll need to say Y here.
  193. You can find documentation about IPC with "info ipc" and also in
  194. section 6.4 of the Linux Programmer's Guide, available from
  195. <http://www.tldp.org/guides.html>.
  196. config SYSVIPC_SYSCTL
  197. bool
  198. depends on SYSVIPC
  199. depends on SYSCTL
  200. default y
  201. config POSIX_MQUEUE
  202. bool "POSIX Message Queues"
  203. depends on NET && EXPERIMENTAL
  204. ---help---
  205. POSIX variant of message queues is a part of IPC. In POSIX message
  206. queues every message has a priority which decides about succession
  207. of receiving it by a process. If you want to compile and run
  208. programs written e.g. for Solaris with use of its POSIX message
  209. queues (functions mq_*) say Y here.
  210. POSIX message queues are visible as a filesystem called 'mqueue'
  211. and can be mounted somewhere if you want to do filesystem
  212. operations on message queues.
  213. If unsure, say Y.
  214. config POSIX_MQUEUE_SYSCTL
  215. bool
  216. depends on POSIX_MQUEUE
  217. depends on SYSCTL
  218. default y
  219. config BSD_PROCESS_ACCT
  220. bool "BSD Process Accounting"
  221. help
  222. If you say Y here, a user level program will be able to instruct the
  223. kernel (via a special system call) to write process accounting
  224. information to a file: whenever a process exits, information about
  225. that process will be appended to the file by the kernel. The
  226. information includes things such as creation time, owning user,
  227. command name, memory usage, controlling terminal etc. (the complete
  228. list is in the struct acct in <file:include/linux/acct.h>). It is
  229. up to the user level program to do useful things with this
  230. information. This is generally a good idea, so say Y.
  231. config BSD_PROCESS_ACCT_V3
  232. bool "BSD Process Accounting version 3 file format"
  233. depends on BSD_PROCESS_ACCT
  234. default n
  235. help
  236. If you say Y here, the process accounting information is written
  237. in a new file format that also logs the process IDs of each
  238. process and it's parent. Note that this file format is incompatible
  239. with previous v0/v1/v2 file formats, so you will need updated tools
  240. for processing it. A preliminary version of these tools is available
  241. at <http://www.gnu.org/software/acct/>.
  242. config TASKSTATS
  243. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  244. depends on NET
  245. default n
  246. help
  247. Export selected statistics for tasks/processes through the
  248. generic netlink interface. Unlike BSD process accounting, the
  249. statistics are available during the lifetime of tasks/processes as
  250. responses to commands. Like BSD accounting, they are sent to user
  251. space on task exit.
  252. Say N if unsure.
  253. config TASK_DELAY_ACCT
  254. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  255. depends on TASKSTATS
  256. help
  257. Collect information on time spent by a task waiting for system
  258. resources like cpu, synchronous block I/O completion and swapping
  259. in pages. Such statistics can help in setting a task's priorities
  260. relative to other tasks for cpu, io, rss limits etc.
  261. Say N if unsure.
  262. config TASK_XACCT
  263. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  264. depends on TASKSTATS
  265. help
  266. Collect extended task accounting data and send the data
  267. to userland for processing over the taskstats interface.
  268. Say N if unsure.
  269. config TASK_IO_ACCOUNTING
  270. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  271. depends on TASK_XACCT
  272. help
  273. Collect information on the number of bytes of storage I/O which this
  274. task has caused.
  275. Say N if unsure.
  276. config AUDIT
  277. bool "Auditing support"
  278. depends on NET
  279. help
  280. Enable auditing infrastructure that can be used with another
  281. kernel subsystem, such as SELinux (which requires this for
  282. logging of avc messages output). Does not do system-call
  283. auditing without CONFIG_AUDITSYSCALL.
  284. config AUDITSYSCALL
  285. bool "Enable system-call auditing support"
  286. depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
  287. default y if SECURITY_SELINUX
  288. help
  289. Enable low-overhead system-call auditing infrastructure that
  290. can be used independently or with another kernel subsystem,
  291. such as SELinux.
  292. config AUDIT_WATCH
  293. def_bool y
  294. depends on AUDITSYSCALL
  295. select FSNOTIFY
  296. config AUDIT_TREE
  297. def_bool y
  298. depends on AUDITSYSCALL
  299. select FSNOTIFY
  300. source "kernel/irq/Kconfig"
  301. menu "RCU Subsystem"
  302. choice
  303. prompt "RCU Implementation"
  304. default TREE_RCU
  305. config TREE_RCU
  306. bool "Tree-based hierarchical RCU"
  307. depends on !PREEMPT && SMP
  308. help
  309. This option selects the RCU implementation that is
  310. designed for very large SMP system with hundreds or
  311. thousands of CPUs. It also scales down nicely to
  312. smaller systems.
  313. config TREE_PREEMPT_RCU
  314. bool "Preemptible tree-based hierarchical RCU"
  315. depends on PREEMPT
  316. help
  317. This option selects the RCU implementation that is
  318. designed for very large SMP systems with hundreds or
  319. thousands of CPUs, but for which real-time response
  320. is also required. It also scales down nicely to
  321. smaller systems.
  322. config TINY_RCU
  323. bool "UP-only small-memory-footprint RCU"
  324. depends on !SMP
  325. help
  326. This option selects the RCU implementation that is
  327. designed for UP systems from which real-time response
  328. is not required. This option greatly reduces the
  329. memory footprint of RCU.
  330. config TINY_PREEMPT_RCU
  331. bool "Preemptible UP-only small-memory-footprint RCU"
  332. depends on !SMP && PREEMPT
  333. help
  334. This option selects the RCU implementation that is designed
  335. for real-time UP systems. This option greatly reduces the
  336. memory footprint of RCU.
  337. endchoice
  338. config PREEMPT_RCU
  339. def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
  340. help
  341. This option enables preemptible-RCU code that is common between
  342. the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
  343. config RCU_TRACE
  344. bool "Enable tracing for RCU"
  345. help
  346. This option provides tracing in RCU which presents stats
  347. in debugfs for debugging RCU implementation.
  348. Say Y here if you want to enable RCU tracing
  349. Say N if you are unsure.
  350. config RCU_FANOUT
  351. int "Tree-based hierarchical RCU fanout value"
  352. range 2 64 if 64BIT
  353. range 2 32 if !64BIT
  354. depends on TREE_RCU || TREE_PREEMPT_RCU
  355. default 64 if 64BIT
  356. default 32 if !64BIT
  357. help
  358. This option controls the fanout of hierarchical implementations
  359. of RCU, allowing RCU to work efficiently on machines with
  360. large numbers of CPUs. This value must be at least the fourth
  361. root of NR_CPUS, which allows NR_CPUS to be insanely large.
  362. The default value of RCU_FANOUT should be used for production
  363. systems, but if you are stress-testing the RCU implementation
  364. itself, small RCU_FANOUT values allow you to test large-system
  365. code paths on small(er) systems.
  366. Select a specific number if testing RCU itself.
  367. Take the default if unsure.
  368. config RCU_FANOUT_EXACT
  369. bool "Disable tree-based hierarchical RCU auto-balancing"
  370. depends on TREE_RCU || TREE_PREEMPT_RCU
  371. default n
  372. help
  373. This option forces use of the exact RCU_FANOUT value specified,
  374. regardless of imbalances in the hierarchy. This is useful for
  375. testing RCU itself, and might one day be useful on systems with
  376. strong NUMA behavior.
  377. Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
  378. Say N if unsure.
  379. config RCU_FAST_NO_HZ
  380. bool "Accelerate last non-dyntick-idle CPU's grace periods"
  381. depends on TREE_RCU && NO_HZ && SMP
  382. default n
  383. help
  384. This option causes RCU to attempt to accelerate grace periods
  385. in order to allow the final CPU to enter dynticks-idle state
  386. more quickly. On the other hand, this option increases the
  387. overhead of the dynticks-idle checking, particularly on systems
  388. with large numbers of CPUs.
  389. Say Y if energy efficiency is critically important, particularly
  390. if you have relatively few CPUs.
  391. Say N if you are unsure.
  392. config TREE_RCU_TRACE
  393. def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
  394. select DEBUG_FS
  395. help
  396. This option provides tracing for the TREE_RCU and
  397. TREE_PREEMPT_RCU implementations, permitting Makefile to
  398. trivially select kernel/rcutree_trace.c.
  399. config RCU_BOOST
  400. bool "Enable RCU priority boosting"
  401. depends on RT_MUTEXES && TINY_PREEMPT_RCU
  402. default n
  403. help
  404. This option boosts the priority of preempted RCU readers that
  405. block the current preemptible RCU grace period for too long.
  406. This option also prevents heavy loads from blocking RCU
  407. callback invocation for all flavors of RCU.
  408. Say Y here if you are working with real-time apps or heavy loads
  409. Say N here if you are unsure.
  410. config RCU_BOOST_PRIO
  411. int "Real-time priority to boost RCU readers to"
  412. range 1 99
  413. depends on RCU_BOOST
  414. default 1
  415. help
  416. This option specifies the real-time priority to which preempted
  417. RCU readers are to be boosted. If you are working with CPU-bound
  418. real-time applications, you should specify a priority higher then
  419. the highest-priority CPU-bound application.
  420. Specify the real-time priority, or take the default if unsure.
  421. config RCU_BOOST_DELAY
  422. int "Milliseconds to delay boosting after RCU grace-period start"
  423. range 0 3000
  424. depends on RCU_BOOST
  425. default 500
  426. help
  427. This option specifies the time to wait after the beginning of
  428. a given grace period before priority-boosting preempted RCU
  429. readers blocking that grace period. Note that any RCU reader
  430. blocking an expedited RCU grace period is boosted immediately.
  431. Accept the default if unsure.
  432. endmenu # "RCU Subsystem"
  433. config IKCONFIG
  434. tristate "Kernel .config support"
  435. ---help---
  436. This option enables the complete Linux kernel ".config" file
  437. contents to be saved in the kernel. It provides documentation
  438. of which kernel options are used in a running kernel or in an
  439. on-disk kernel. This information can be extracted from the kernel
  440. image file with the script scripts/extract-ikconfig and used as
  441. input to rebuild the current kernel or to build another kernel.
  442. It can also be extracted from a running kernel by reading
  443. /proc/config.gz if enabled (below).
  444. config IKCONFIG_PROC
  445. bool "Enable access to .config through /proc/config.gz"
  446. depends on IKCONFIG && PROC_FS
  447. ---help---
  448. This option enables access to the kernel configuration file
  449. through /proc/config.gz.
  450. config LOG_BUF_SHIFT
  451. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  452. range 12 21
  453. default 17
  454. help
  455. Select kernel log buffer size as a power of 2.
  456. Examples:
  457. 17 => 128 KB
  458. 16 => 64 KB
  459. 15 => 32 KB
  460. 14 => 16 KB
  461. 13 => 8 KB
  462. 12 => 4 KB
  463. #
  464. # Architectures with an unreliable sched_clock() should select this:
  465. #
  466. config HAVE_UNSTABLE_SCHED_CLOCK
  467. bool
  468. menuconfig CGROUPS
  469. boolean "Control Group support"
  470. depends on EVENTFD
  471. help
  472. This option adds support for grouping sets of processes together, for
  473. use with process control subsystems such as Cpusets, CFS, memory
  474. controls or device isolation.
  475. See
  476. - Documentation/scheduler/sched-design-CFS.txt (CFS)
  477. - Documentation/cgroups/ (features for grouping, isolation
  478. and resource control)
  479. Say N if unsure.
  480. if CGROUPS
  481. config CGROUP_DEBUG
  482. bool "Example debug cgroup subsystem"
  483. default n
  484. help
  485. This option enables a simple cgroup subsystem that
  486. exports useful debugging information about the cgroups
  487. framework.
  488. Say N if unsure.
  489. config CGROUP_NS
  490. bool "Namespace cgroup subsystem"
  491. help
  492. Provides a simple namespace cgroup subsystem to
  493. provide hierarchical naming of sets of namespaces,
  494. for instance virtual servers and checkpoint/restart
  495. jobs.
  496. config CGROUP_FREEZER
  497. bool "Freezer cgroup subsystem"
  498. help
  499. Provides a way to freeze and unfreeze all tasks in a
  500. cgroup.
  501. config CGROUP_DEVICE
  502. bool "Device controller for cgroups"
  503. help
  504. Provides a cgroup implementing whitelists for devices which
  505. a process in the cgroup can mknod or open.
  506. config CPUSETS
  507. bool "Cpuset support"
  508. help
  509. This option will let you create and manage CPUSETs which
  510. allow dynamically partitioning a system into sets of CPUs and
  511. Memory Nodes and assigning tasks to run only within those sets.
  512. This is primarily useful on large SMP or NUMA systems.
  513. Say N if unsure.
  514. config PROC_PID_CPUSET
  515. bool "Include legacy /proc/<pid>/cpuset file"
  516. depends on CPUSETS
  517. default y
  518. config CGROUP_CPUACCT
  519. bool "Simple CPU accounting cgroup subsystem"
  520. help
  521. Provides a simple Resource Controller for monitoring the
  522. total CPU consumed by the tasks in a cgroup.
  523. config RESOURCE_COUNTERS
  524. bool "Resource counters"
  525. help
  526. This option enables controller independent resource accounting
  527. infrastructure that works with cgroups.
  528. config CGROUP_MEM_RES_CTLR
  529. bool "Memory Resource Controller for Control Groups"
  530. depends on RESOURCE_COUNTERS
  531. select MM_OWNER
  532. help
  533. Provides a memory resource controller that manages both anonymous
  534. memory and page cache. (See Documentation/cgroups/memory.txt)
  535. Note that setting this option increases fixed memory overhead
  536. associated with each page of memory in the system. By this,
  537. 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
  538. usage tracking struct at boot. Total amount of this is printed out
  539. at boot.
  540. Only enable when you're ok with these trade offs and really
  541. sure you need the memory resource controller. Even when you enable
  542. this, you can set "cgroup_disable=memory" at your boot option to
  543. disable memory resource controller and you can avoid overheads.
  544. (and lose benefits of memory resource controller)
  545. This config option also selects MM_OWNER config option, which
  546. could in turn add some fork/exit overhead.
  547. config CGROUP_MEM_RES_CTLR_SWAP
  548. bool "Memory Resource Controller Swap Extension"
  549. depends on CGROUP_MEM_RES_CTLR && SWAP
  550. help
  551. Add swap management feature to memory resource controller. When you
  552. enable this, you can limit mem+swap usage per cgroup. In other words,
  553. when you disable this, memory resource controller has no cares to
  554. usage of swap...a process can exhaust all of the swap. This extension
  555. is useful when you want to avoid exhaustion swap but this itself
  556. adds more overheads and consumes memory for remembering information.
  557. Especially if you use 32bit system or small memory system, please
  558. be careful about enabling this. When memory resource controller
  559. is disabled by boot option, this will be automatically disabled and
  560. there will be no overhead from this. Even when you set this config=y,
  561. if boot option "noswapaccount" is set, swap will not be accounted.
  562. Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
  563. size is 4096bytes, 512k per 1Gbytes of swap.
  564. config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  565. bool "Memory Resource Controller Swap Extension enabled by default"
  566. depends on CGROUP_MEM_RES_CTLR_SWAP
  567. default y
  568. help
  569. Memory Resource Controller Swap Extension comes with its price in
  570. a bigger memory consumption. General purpose distribution kernels
  571. which want to enable the feature but keep it disabled by default
  572. and let the user enable it by swapaccount boot command line
  573. parameter should have this option unselected.
  574. For those who want to have the feature enabled by default should
  575. select this option (if, for some reason, they need to disable it
  576. then noswapaccount does the trick).
  577. menuconfig CGROUP_SCHED
  578. bool "Group CPU scheduler"
  579. depends on EXPERIMENTAL
  580. default n
  581. help
  582. This feature lets CPU scheduler recognize task groups and control CPU
  583. bandwidth allocation to such task groups. It uses cgroups to group
  584. tasks.
  585. if CGROUP_SCHED
  586. config FAIR_GROUP_SCHED
  587. bool "Group scheduling for SCHED_OTHER"
  588. depends on CGROUP_SCHED
  589. default CGROUP_SCHED
  590. config RT_GROUP_SCHED
  591. bool "Group scheduling for SCHED_RR/FIFO"
  592. depends on EXPERIMENTAL
  593. depends on CGROUP_SCHED
  594. default n
  595. help
  596. This feature lets you explicitly allocate real CPU bandwidth
  597. to task groups. If enabled, it will also make it impossible to
  598. schedule realtime tasks for non-root users until you allocate
  599. realtime bandwidth for them.
  600. See Documentation/scheduler/sched-rt-group.txt for more information.
  601. endif #CGROUP_SCHED
  602. config BLK_CGROUP
  603. tristate "Block IO controller"
  604. depends on BLOCK
  605. default n
  606. ---help---
  607. Generic block IO controller cgroup interface. This is the common
  608. cgroup interface which should be used by various IO controlling
  609. policies.
  610. Currently, CFQ IO scheduler uses it to recognize task groups and
  611. control disk bandwidth allocation (proportional time slice allocation)
  612. to such task groups. It is also used by bio throttling logic in
  613. block layer to implement upper limit in IO rates on a device.
  614. This option only enables generic Block IO controller infrastructure.
  615. One needs to also enable actual IO controlling logic/policy. For
  616. enabling proportional weight division of disk bandwidth in CFQ seti
  617. CONFIG_CFQ_GROUP_IOSCHED=y and for enabling throttling policy set
  618. CONFIG_BLK_THROTTLE=y.
  619. See Documentation/cgroups/blkio-controller.txt for more information.
  620. config DEBUG_BLK_CGROUP
  621. bool "Enable Block IO controller debugging"
  622. depends on BLK_CGROUP
  623. default n
  624. ---help---
  625. Enable some debugging help. Currently it exports additional stat
  626. files in a cgroup which can be useful for debugging.
  627. endif # CGROUPS
  628. menuconfig NAMESPACES
  629. bool "Namespaces support" if EXPERT
  630. default !EXPERT
  631. help
  632. Provides the way to make tasks work with different objects using
  633. the same id. For example same IPC id may refer to different objects
  634. or same user id or pid may refer to different tasks when used in
  635. different namespaces.
  636. if NAMESPACES
  637. config UTS_NS
  638. bool "UTS namespace"
  639. default y
  640. help
  641. In this namespace tasks see different info provided with the
  642. uname() system call
  643. config IPC_NS
  644. bool "IPC namespace"
  645. depends on (SYSVIPC || POSIX_MQUEUE)
  646. default y
  647. help
  648. In this namespace tasks work with IPC ids which correspond to
  649. different IPC objects in different namespaces.
  650. config USER_NS
  651. bool "User namespace (EXPERIMENTAL)"
  652. depends on EXPERIMENTAL
  653. default y
  654. help
  655. This allows containers, i.e. vservers, to use user namespaces
  656. to provide different user info for different servers.
  657. If unsure, say N.
  658. config PID_NS
  659. bool "PID Namespaces"
  660. default y
  661. help
  662. Support process id namespaces. This allows having multiple
  663. processes with the same pid as long as they are in different
  664. pid namespaces. This is a building block of containers.
  665. config NET_NS
  666. bool "Network namespace"
  667. depends on NET
  668. default y
  669. help
  670. Allow user space to create what appear to be multiple instances
  671. of the network stack.
  672. endif # NAMESPACES
  673. config SCHED_AUTOGROUP
  674. bool "Automatic process group scheduling"
  675. select EVENTFD
  676. select CGROUPS
  677. select CGROUP_SCHED
  678. select FAIR_GROUP_SCHED
  679. help
  680. This option optimizes the scheduler for common desktop workloads by
  681. automatically creating and populating task groups. This separation
  682. of workloads isolates aggressive CPU burners (like build jobs) from
  683. desktop applications. Task group autogeneration is currently based
  684. upon task session.
  685. config MM_OWNER
  686. bool
  687. config SYSFS_DEPRECATED
  688. bool "enable deprecated sysfs features to support old userspace tools"
  689. depends on SYSFS
  690. default n
  691. help
  692. This option adds code that switches the layout of the "block" class
  693. devices, to not show up in /sys/class/block/, but only in
  694. /sys/block/.
  695. This switch is only active when the sysfs.deprecated=1 boot option is
  696. passed or the SYSFS_DEPRECATED_V2 option is set.
  697. This option allows new kernels to run on old distributions and tools,
  698. which might get confused by /sys/class/block/. Since 2007/2008 all
  699. major distributions and tools handle this just fine.
  700. Recent distributions and userspace tools after 2009/2010 depend on
  701. the existence of /sys/class/block/, and will not work with this
  702. option enabled.
  703. Only if you are using a new kernel on an old distribution, you might
  704. need to say Y here.
  705. config SYSFS_DEPRECATED_V2
  706. bool "enabled deprecated sysfs features by default"
  707. default n
  708. depends on SYSFS
  709. depends on SYSFS_DEPRECATED
  710. help
  711. Enable deprecated sysfs by default.
  712. See the CONFIG_SYSFS_DEPRECATED option for more details about this
  713. option.
  714. Only if you are using a new kernel on an old distribution, you might
  715. need to say Y here. Even then, odds are you would not need it
  716. enabled, you can always pass the boot option if absolutely necessary.
  717. config RELAY
  718. bool "Kernel->user space relay support (formerly relayfs)"
  719. help
  720. This option enables support for relay interface support in
  721. certain file systems (such as debugfs).
  722. It is designed to provide an efficient mechanism for tools and
  723. facilities to relay large amounts of data from kernel space to
  724. user space.
  725. If unsure, say N.
  726. config BLK_DEV_INITRD
  727. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  728. depends on BROKEN || !FRV
  729. help
  730. The initial RAM filesystem is a ramfs which is loaded by the
  731. boot loader (loadlin or lilo) and that is mounted as root
  732. before the normal boot procedure. It is typically used to
  733. load modules needed to mount the "real" root file system,
  734. etc. See <file:Documentation/initrd.txt> for details.
  735. If RAM disk support (BLK_DEV_RAM) is also included, this
  736. also enables initial RAM disk (initrd) support and adds
  737. 15 Kbytes (more on some other architectures) to the kernel size.
  738. If unsure say Y.
  739. if BLK_DEV_INITRD
  740. source "usr/Kconfig"
  741. endif
  742. config CC_OPTIMIZE_FOR_SIZE
  743. bool "Optimize for size"
  744. default y
  745. help
  746. Enabling this option will pass "-Os" instead of "-O2" to gcc
  747. resulting in a smaller kernel.
  748. If unsure, say Y.
  749. config SYSCTL
  750. bool
  751. config ANON_INODES
  752. bool
  753. menuconfig EXPERT
  754. bool "Configure standard kernel features (expert users)"
  755. help
  756. This option allows certain base kernel options and settings
  757. to be disabled or tweaked. This is for specialized
  758. environments which can tolerate a "non-standard" kernel.
  759. Only use this if you really know what you are doing.
  760. config EMBEDDED
  761. bool "Embedded system"
  762. select EXPERT
  763. help
  764. This option should be enabled if compiling the kernel for
  765. an embedded system so certain expert options are available
  766. for configuration.
  767. config UID16
  768. bool "Enable 16-bit UID system calls" if EXPERT
  769. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
  770. default y
  771. help
  772. This enables the legacy 16-bit UID syscall wrappers.
  773. config SYSCTL_SYSCALL
  774. bool "Sysctl syscall support" if EXPERT
  775. depends on PROC_SYSCTL
  776. default y
  777. select SYSCTL
  778. ---help---
  779. sys_sysctl uses binary paths that have been found challenging
  780. to properly maintain and use. The interface in /proc/sys
  781. using paths with ascii names is now the primary path to this
  782. information.
  783. Almost nothing using the binary sysctl interface so if you are
  784. trying to save some space it is probably safe to disable this,
  785. making your kernel marginally smaller.
  786. If unsure say Y here.
  787. config KALLSYMS
  788. bool "Load all symbols for debugging/ksymoops" if EXPERT
  789. default y
  790. help
  791. Say Y here to let the kernel print out symbolic crash information and
  792. symbolic stack backtraces. This increases the size of the kernel
  793. somewhat, as all symbols have to be loaded into the kernel image.
  794. config KALLSYMS_ALL
  795. bool "Include all symbols in kallsyms"
  796. depends on DEBUG_KERNEL && KALLSYMS
  797. help
  798. Normally kallsyms only contains the symbols of functions, for nicer
  799. OOPS messages. Some debuggers can use kallsyms for other
  800. symbols too: say Y here to include all symbols, if you need them
  801. and you don't care about adding 300k to the size of your kernel.
  802. Say N.
  803. config KALLSYMS_EXTRA_PASS
  804. bool "Do an extra kallsyms pass"
  805. depends on KALLSYMS
  806. help
  807. If kallsyms is not working correctly, the build will fail with
  808. inconsistent kallsyms data. If that occurs, log a bug report and
  809. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  810. Always say N here unless you find a bug in kallsyms, which must be
  811. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  812. you wait for kallsyms to be fixed.
  813. config HOTPLUG
  814. bool "Support for hot-pluggable devices" if EXPERT
  815. default y
  816. help
  817. This option is provided for the case where no hotplug or uevent
  818. capabilities is wanted by the kernel. You should only consider
  819. disabling this option for embedded systems that do not use modules, a
  820. dynamic /dev tree, or dynamic device discovery. Just say Y.
  821. config PRINTK
  822. default y
  823. bool "Enable support for printk" if EXPERT
  824. help
  825. This option enables normal printk support. Removing it
  826. eliminates most of the message strings from the kernel image
  827. and makes the kernel more or less silent. As this makes it
  828. very difficult to diagnose system problems, saying N here is
  829. strongly discouraged.
  830. config BUG
  831. bool "BUG() support" if EXPERT
  832. default y
  833. help
  834. Disabling this option eliminates support for BUG and WARN, reducing
  835. the size of your kernel image and potentially quietly ignoring
  836. numerous fatal conditions. You should only consider disabling this
  837. option for embedded systems with no facilities for reporting errors.
  838. Just say Y.
  839. config ELF_CORE
  840. default y
  841. bool "Enable ELF core dumps" if EXPERT
  842. help
  843. Enable support for generating core dumps. Disabling saves about 4k.
  844. config PCSPKR_PLATFORM
  845. bool "Enable PC-Speaker support" if EXPERT
  846. depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
  847. default y
  848. help
  849. This option allows to disable the internal PC-Speaker
  850. support, saving some memory.
  851. config BASE_FULL
  852. default y
  853. bool "Enable full-sized data structures for core" if EXPERT
  854. help
  855. Disabling this option reduces the size of miscellaneous core
  856. kernel data structures. This saves memory on small machines,
  857. but may reduce performance.
  858. config FUTEX
  859. bool "Enable futex support" if EXPERT
  860. default y
  861. select RT_MUTEXES
  862. help
  863. Disabling this option will cause the kernel to be built without
  864. support for "fast userspace mutexes". The resulting kernel may not
  865. run glibc-based applications correctly.
  866. config EPOLL
  867. bool "Enable eventpoll support" if EXPERT
  868. default y
  869. select ANON_INODES
  870. help
  871. Disabling this option will cause the kernel to be built without
  872. support for epoll family of system calls.
  873. config SIGNALFD
  874. bool "Enable signalfd() system call" if EXPERT
  875. select ANON_INODES
  876. default y
  877. help
  878. Enable the signalfd() system call that allows to receive signals
  879. on a file descriptor.
  880. If unsure, say Y.
  881. config TIMERFD
  882. bool "Enable timerfd() system call" if EXPERT
  883. select ANON_INODES
  884. default y
  885. help
  886. Enable the timerfd() system call that allows to receive timer
  887. events on a file descriptor.
  888. If unsure, say Y.
  889. config EVENTFD
  890. bool "Enable eventfd() system call" if EXPERT
  891. select ANON_INODES
  892. default y
  893. help
  894. Enable the eventfd() system call that allows to receive both
  895. kernel notification (ie. KAIO) or userspace notifications.
  896. If unsure, say Y.
  897. config SHMEM
  898. bool "Use full shmem filesystem" if EXPERT
  899. default y
  900. depends on MMU
  901. help
  902. The shmem is an internal filesystem used to manage shared memory.
  903. It is backed by swap and manages resource limits. It is also exported
  904. to userspace as tmpfs if TMPFS is enabled. Disabling this
  905. option replaces shmem and tmpfs with the much simpler ramfs code,
  906. which may be appropriate on small systems without swap.
  907. config AIO
  908. bool "Enable AIO support" if EXPERT
  909. default y
  910. help
  911. This option enables POSIX asynchronous I/O which may by used
  912. by some high performance threaded applications. Disabling
  913. this option saves about 7k.
  914. config HAVE_PERF_EVENTS
  915. bool
  916. help
  917. See tools/perf/design.txt for details.
  918. config PERF_USE_VMALLOC
  919. bool
  920. help
  921. See tools/perf/design.txt for details
  922. menu "Kernel Performance Events And Counters"
  923. config PERF_EVENTS
  924. bool "Kernel performance events and counters"
  925. default y if (PROFILING || PERF_COUNTERS)
  926. depends on HAVE_PERF_EVENTS
  927. select ANON_INODES
  928. select IRQ_WORK
  929. help
  930. Enable kernel support for various performance events provided
  931. by software and hardware.
  932. Software events are supported either built-in or via the
  933. use of generic tracepoints.
  934. Most modern CPUs support performance events via performance
  935. counter registers. These registers count the number of certain
  936. types of hw events: such as instructions executed, cachemisses
  937. suffered, or branches mis-predicted - without slowing down the
  938. kernel or applications. These registers can also trigger interrupts
  939. when a threshold number of events have passed - and can thus be
  940. used to profile the code that runs on that CPU.
  941. The Linux Performance Event subsystem provides an abstraction of
  942. these software and hardware event capabilities, available via a
  943. system call and used by the "perf" utility in tools/perf/. It
  944. provides per task and per CPU counters, and it provides event
  945. capabilities on top of those.
  946. Say Y if unsure.
  947. config PERF_COUNTERS
  948. bool "Kernel performance counters (old config option)"
  949. depends on HAVE_PERF_EVENTS
  950. help
  951. This config has been obsoleted by the PERF_EVENTS
  952. config option - please see that one for details.
  953. It has no effect on the kernel whether you enable
  954. it or not, it is a compatibility placeholder.
  955. Say N if unsure.
  956. config DEBUG_PERF_USE_VMALLOC
  957. default n
  958. bool "Debug: use vmalloc to back perf mmap() buffers"
  959. depends on PERF_EVENTS && DEBUG_KERNEL
  960. select PERF_USE_VMALLOC
  961. help
  962. Use vmalloc memory to back perf mmap() buffers.
  963. Mostly useful for debugging the vmalloc code on platforms
  964. that don't require it.
  965. Say N if unsure.
  966. endmenu
  967. config VM_EVENT_COUNTERS
  968. default y
  969. bool "Enable VM event counters for /proc/vmstat" if EXPERT
  970. help
  971. VM event counters are needed for event counts to be shown.
  972. This option allows the disabling of the VM event counters
  973. on EXPERT systems. /proc/vmstat will only show page counts
  974. if VM event counters are disabled.
  975. config PCI_QUIRKS
  976. default y
  977. bool "Enable PCI quirk workarounds" if EXPERT
  978. depends on PCI
  979. help
  980. This enables workarounds for various PCI chipset
  981. bugs/quirks. Disable this only if your target machine is
  982. unaffected by PCI quirks.
  983. config SLUB_DEBUG
  984. default y
  985. bool "Enable SLUB debugging support" if EXPERT
  986. depends on SLUB && SYSFS
  987. help
  988. SLUB has extensive debug support features. Disabling these can
  989. result in significant savings in code size. This also disables
  990. SLUB sysfs support. /sys/slab will not exist and there will be
  991. no support for cache validation etc.
  992. config COMPAT_BRK
  993. bool "Disable heap randomization"
  994. default y
  995. help
  996. Randomizing heap placement makes heap exploits harder, but it
  997. also breaks ancient binaries (including anything libc5 based).
  998. This option changes the bootup default to heap randomization
  999. disabled, and can be overridden at runtime by setting
  1000. /proc/sys/kernel/randomize_va_space to 2.
  1001. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  1002. choice
  1003. prompt "Choose SLAB allocator"
  1004. default SLUB
  1005. help
  1006. This option allows to select a slab allocator.
  1007. config SLAB
  1008. bool "SLAB"
  1009. help
  1010. The regular slab allocator that is established and known to work
  1011. well in all environments. It organizes cache hot objects in
  1012. per cpu and per node queues.
  1013. config SLUB
  1014. bool "SLUB (Unqueued Allocator)"
  1015. help
  1016. SLUB is a slab allocator that minimizes cache line usage
  1017. instead of managing queues of cached objects (SLAB approach).
  1018. Per cpu caching is realized using slabs of objects instead
  1019. of queues of objects. SLUB can use memory efficiently
  1020. and has enhanced diagnostics. SLUB is the default choice for
  1021. a slab allocator.
  1022. config SLOB
  1023. depends on EXPERT
  1024. bool "SLOB (Simple Allocator)"
  1025. help
  1026. SLOB replaces the stock allocator with a drastically simpler
  1027. allocator. SLOB is generally more space efficient but
  1028. does not perform as well on large systems.
  1029. endchoice
  1030. config MMAP_ALLOW_UNINITIALIZED
  1031. bool "Allow mmapped anonymous memory to be uninitialized"
  1032. depends on EXPERT && !MMU
  1033. default n
  1034. help
  1035. Normally, and according to the Linux spec, anonymous memory obtained
  1036. from mmap() has it's contents cleared before it is passed to
  1037. userspace. Enabling this config option allows you to request that
  1038. mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
  1039. providing a huge performance boost. If this option is not enabled,
  1040. then the flag will be ignored.
  1041. This is taken advantage of by uClibc's malloc(), and also by
  1042. ELF-FDPIC binfmt's brk and stack allocator.
  1043. Because of the obvious security issues, this option should only be
  1044. enabled on embedded devices where you control what is run in
  1045. userspace. Since that isn't generally a problem on no-MMU systems,
  1046. it is normally safe to say Y here.
  1047. See Documentation/nommu-mmap.txt for more information.
  1048. config PROFILING
  1049. bool "Profiling support"
  1050. help
  1051. Say Y here to enable the extended profiling support mechanisms used
  1052. by profilers such as OProfile.
  1053. #
  1054. # Place an empty function call at each tracepoint site. Can be
  1055. # dynamically changed for a probe function.
  1056. #
  1057. config TRACEPOINTS
  1058. bool
  1059. source "arch/Kconfig"
  1060. endmenu # General setup
  1061. config HAVE_GENERIC_DMA_COHERENT
  1062. bool
  1063. default n
  1064. config SLABINFO
  1065. bool
  1066. depends on PROC_FS
  1067. depends on SLAB || SLUB_DEBUG
  1068. default y
  1069. config RT_MUTEXES
  1070. boolean
  1071. config BASE_SMALL
  1072. int
  1073. default 0 if BASE_FULL
  1074. default 1 if !BASE_FULL
  1075. menuconfig MODULES
  1076. bool "Enable loadable module support"
  1077. help
  1078. Kernel modules are small pieces of compiled code which can
  1079. be inserted in the running kernel, rather than being
  1080. permanently built into the kernel. You use the "modprobe"
  1081. tool to add (and sometimes remove) them. If you say Y here,
  1082. many parts of the kernel can be built as modules (by
  1083. answering M instead of Y where indicated): this is most
  1084. useful for infrequently used options which are not required
  1085. for booting. For more information, see the man pages for
  1086. modprobe, lsmod, modinfo, insmod and rmmod.
  1087. If you say Y here, you will need to run "make
  1088. modules_install" to put the modules under /lib/modules/
  1089. where modprobe can find them (you may need to be root to do
  1090. this).
  1091. If unsure, say Y.
  1092. if MODULES
  1093. config MODULE_FORCE_LOAD
  1094. bool "Forced module loading"
  1095. default n
  1096. help
  1097. Allow loading of modules without version information (ie. modprobe
  1098. --force). Forced module loading sets the 'F' (forced) taint flag and
  1099. is usually a really bad idea.
  1100. config MODULE_UNLOAD
  1101. bool "Module unloading"
  1102. help
  1103. Without this option you will not be able to unload any
  1104. modules (note that some modules may not be unloadable
  1105. anyway), which makes your kernel smaller, faster
  1106. and simpler. If unsure, say Y.
  1107. config MODULE_FORCE_UNLOAD
  1108. bool "Forced module unloading"
  1109. depends on MODULE_UNLOAD && EXPERIMENTAL
  1110. help
  1111. This option allows you to force a module to unload, even if the
  1112. kernel believes it is unsafe: the kernel will remove the module
  1113. without waiting for anyone to stop using it (using the -f option to
  1114. rmmod). This is mainly for kernel developers and desperate users.
  1115. If unsure, say N.
  1116. config MODVERSIONS
  1117. bool "Module versioning support"
  1118. help
  1119. Usually, you have to use modules compiled with your kernel.
  1120. Saying Y here makes it sometimes possible to use modules
  1121. compiled for different kernels, by adding enough information
  1122. to the modules to (hopefully) spot any changes which would
  1123. make them incompatible with the kernel you are running. If
  1124. unsure, say N.
  1125. config MODULE_SRCVERSION_ALL
  1126. bool "Source checksum for all modules"
  1127. help
  1128. Modules which contain a MODULE_VERSION get an extra "srcversion"
  1129. field inserted into their modinfo section, which contains a
  1130. sum of the source files which made it. This helps maintainers
  1131. see exactly which source was used to build a module (since
  1132. others sometimes change the module source without updating
  1133. the version). With this option, such a "srcversion" field
  1134. will be created for all modules. If unsure, say N.
  1135. endif # MODULES
  1136. config INIT_ALL_POSSIBLE
  1137. bool
  1138. help
  1139. Back when each arch used to define their own cpu_online_map and
  1140. cpu_possible_map, some of them chose to initialize cpu_possible_map
  1141. with all 1s, and others with all 0s. When they were centralised,
  1142. it was better to provide this option than to break all the archs
  1143. and have several arch maintainers pursuing me down dark alleys.
  1144. config STOP_MACHINE
  1145. bool
  1146. default y
  1147. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  1148. help
  1149. Need stop_machine() primitive.
  1150. source "block/Kconfig"
  1151. config PREEMPT_NOTIFIERS
  1152. bool
  1153. config PADATA
  1154. depends on SMP
  1155. bool
  1156. source "kernel/Kconfig.locks"