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 drivers that have been replaced by something else, and/or are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