Kconfig 51 KB

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  1. config ARCH
  2. string
  3. option env="ARCH"
  4. config KERNELVERSION
  5. string
  6. option env="KERNELVERSION"
  7. config DEFCONFIG_LIST
  8. string
  9. depends on !UML
  10. option defconfig_list
  11. default "/lib/modules/$UNAME_RELEASE/.config"
  12. default "/etc/kernel-config"
  13. default "/boot/config-$UNAME_RELEASE"
  14. default "$ARCH_DEFCONFIG"
  15. default "arch/$ARCH/defconfig"
  16. config CONSTRUCTORS
  17. bool
  18. depends on !UML
  19. config HAVE_IRQ_WORK
  20. bool
  21. config IRQ_WORK
  22. bool
  23. depends on HAVE_IRQ_WORK
  24. config BUILDTIME_EXTABLE_SORT
  25. bool
  26. menu "General setup"
  27. config EXPERIMENTAL
  28. bool "Prompt for development and/or incomplete code/drivers"
  29. ---help---
  30. Some of the various things that Linux supports (such as network
  31. drivers, file systems, network protocols, etc.) can be in a state
  32. of development where the functionality, stability, or the level of
  33. testing is not yet high enough for general use. This is usually
  34. known as the "alpha-test" phase among developers. If a feature is
  35. currently in alpha-test, then the developers usually discourage
  36. uninformed widespread use of this feature by the general public to
  37. avoid "Why doesn't this work?" type mail messages. However, active
  38. testing and use of these systems is welcomed. Just be aware that it
  39. may not meet the normal level of reliability or it may fail to work
  40. in some special cases. Detailed bug reports from people familiar
  41. with the kernel internals are usually welcomed by the developers
  42. (before submitting bug reports, please read the documents
  43. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  44. <file:Documentation/BUG-HUNTING>, and
  45. <file:Documentation/oops-tracing.txt> in the kernel source).
  46. This option will also make obsoleted drivers available. These are
  47. drivers that have been replaced by something else, and/or are
  48. scheduled to be removed in a future kernel release.
  49. Unless you intend to help test and develop a feature or driver that
  50. falls into this category, or you have a situation that requires
  51. using these features, you should probably say N here, which will
  52. cause the configurator to present you with fewer choices. If
  53. you say Y here, you will be offered the choice of using features or
  54. drivers that are currently considered to be in the alpha-test phase.
  55. config BROKEN
  56. bool
  57. config BROKEN_ON_SMP
  58. bool
  59. depends on BROKEN || !SMP
  60. default y
  61. config INIT_ENV_ARG_LIMIT
  62. int
  63. default 32 if !UML
  64. default 128 if UML
  65. help
  66. Maximum of each of the number of arguments and environment
  67. variables passed to init from the kernel command line.
  68. config CROSS_COMPILE
  69. string "Cross-compiler tool prefix"
  70. help
  71. Same as running 'make CROSS_COMPILE=prefix-' but stored for
  72. default make runs in this kernel build directory. You don't
  73. need to set this unless you want the configured kernel build
  74. directory to select the cross-compiler automatically.
  75. config LOCALVERSION
  76. string "Local version - append to kernel release"
  77. help
  78. Append an extra string to the end of your kernel version.
  79. This will show up when you type uname, for example.
  80. The string you set here will be appended after the contents of
  81. any files with a filename matching localversion* in your
  82. object and source tree, in that order. Your total string can
  83. be a maximum of 64 characters.
  84. config LOCALVERSION_AUTO
  85. bool "Automatically append version information to the version string"
  86. default y
  87. help
  88. This will try to automatically determine if the current tree is a
  89. release tree by looking for git tags that belong to the current
  90. top of tree revision.
  91. A string of the format -gxxxxxxxx will be added to the localversion
  92. if a git-based tree is found. The string generated by this will be
  93. appended after any matching localversion* files, and after the value
  94. set in CONFIG_LOCALVERSION.
  95. (The actual string used here is the first eight characters produced
  96. by running the command:
  97. $ git rev-parse --verify HEAD
  98. which is done within the script "scripts/setlocalversion".)
  99. config HAVE_KERNEL_GZIP
  100. bool
  101. config HAVE_KERNEL_BZIP2
  102. bool
  103. config HAVE_KERNEL_LZMA
  104. bool
  105. config HAVE_KERNEL_XZ
  106. bool
  107. config HAVE_KERNEL_LZO
  108. bool
  109. choice
  110. prompt "Kernel compression mode"
  111. default KERNEL_GZIP
  112. depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
  113. help
  114. The linux kernel is a kind of self-extracting executable.
  115. Several compression algorithms are available, which differ
  116. in efficiency, compression and decompression speed.
  117. Compression speed is only relevant when building a kernel.
  118. Decompression speed is relevant at each boot.
  119. If you have any problems with bzip2 or lzma compressed
  120. kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
  121. version of this functionality (bzip2 only), for 2.4, was
  122. supplied by Christian Ludwig)
  123. High compression options are mostly useful for users, who
  124. are low on disk space (embedded systems), but for whom ram
  125. size matters less.
  126. If in doubt, select 'gzip'
  127. config KERNEL_GZIP
  128. bool "Gzip"
  129. depends on HAVE_KERNEL_GZIP
  130. help
  131. The old and tried gzip compression. It provides a good balance
  132. between compression ratio and decompression speed.
  133. config KERNEL_BZIP2
  134. bool "Bzip2"
  135. depends on HAVE_KERNEL_BZIP2
  136. help
  137. Its compression ratio and speed is intermediate.
  138. Decompression speed is slowest among the three. The kernel
  139. size is about 10% smaller with bzip2, in comparison to gzip.
  140. Bzip2 uses a large amount of memory. For modern kernels you
  141. will need at least 8MB RAM or more for booting.
  142. config KERNEL_LZMA
  143. bool "LZMA"
  144. depends on HAVE_KERNEL_LZMA
  145. help
  146. The most recent compression algorithm.
  147. Its ratio is best, decompression speed is between the other
  148. two. Compression is slowest. The kernel size is about 33%
  149. smaller with LZMA in comparison to gzip.
  150. config KERNEL_XZ
  151. bool "XZ"
  152. depends on HAVE_KERNEL_XZ
  153. help
  154. XZ uses the LZMA2 algorithm and instruction set specific
  155. BCJ filters which can improve compression ratio of executable
  156. code. The size of the kernel is about 30% smaller with XZ in
  157. comparison to gzip. On architectures for which there is a BCJ
  158. filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
  159. will create a few percent smaller kernel than plain LZMA.
  160. The speed is about the same as with LZMA: The decompression
  161. speed of XZ is better than that of bzip2 but worse than gzip
  162. and LZO. Compression is slow.
  163. config KERNEL_LZO
  164. bool "LZO"
  165. depends on HAVE_KERNEL_LZO
  166. help
  167. Its compression ratio is the poorest among the 4. The kernel
  168. size is about 10% bigger than gzip; however its speed
  169. (both compression and decompression) is the fastest.
  170. endchoice
  171. config DEFAULT_HOSTNAME
  172. string "Default hostname"
  173. default "(none)"
  174. help
  175. This option determines the default system hostname before userspace
  176. calls sethostname(2). The kernel traditionally uses "(none)" here,
  177. but you may wish to use a different default here to make a minimal
  178. system more usable with less configuration.
  179. config SWAP
  180. bool "Support for paging of anonymous memory (swap)"
  181. depends on MMU && BLOCK
  182. default y
  183. help
  184. This option allows you to choose whether you want to have support
  185. for so called swap devices or swap files in your kernel that are
  186. used to provide more virtual memory than the actual RAM present
  187. in your computer. If unsure say Y.
  188. config SYSVIPC
  189. bool "System V IPC"
  190. ---help---
  191. Inter Process Communication is a suite of library functions and
  192. system calls which let processes (running programs) synchronize and
  193. exchange information. It is generally considered to be a good thing,
  194. and some programs won't run unless you say Y here. In particular, if
  195. you want to run the DOS emulator dosemu under Linux (read the
  196. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  197. you'll need to say Y here.
  198. You can find documentation about IPC with "info ipc" and also in
  199. section 6.4 of the Linux Programmer's Guide, available from
  200. <http://www.tldp.org/guides.html>.
  201. config SYSVIPC_SYSCTL
  202. bool
  203. depends on SYSVIPC
  204. depends on SYSCTL
  205. default y
  206. config POSIX_MQUEUE
  207. bool "POSIX Message Queues"
  208. depends on NET && EXPERIMENTAL
  209. ---help---
  210. POSIX variant of message queues is a part of IPC. In POSIX message
  211. queues every message has a priority which decides about succession
  212. of receiving it by a process. If you want to compile and run
  213. programs written e.g. for Solaris with use of its POSIX message
  214. queues (functions mq_*) say Y here.
  215. POSIX message queues are visible as a filesystem called 'mqueue'
  216. and can be mounted somewhere if you want to do filesystem
  217. operations on message queues.
  218. If unsure, say Y.
  219. config POSIX_MQUEUE_SYSCTL
  220. bool
  221. depends on POSIX_MQUEUE
  222. depends on SYSCTL
  223. default y
  224. config BSD_PROCESS_ACCT
  225. bool "BSD Process Accounting"
  226. help
  227. If you say Y here, a user level program will be able to instruct the
  228. kernel (via a special system call) to write process accounting
  229. information to a file: whenever a process exits, information about
  230. that process will be appended to the file by the kernel. The
  231. information includes things such as creation time, owning user,
  232. command name, memory usage, controlling terminal etc. (the complete
  233. list is in the struct acct in <file:include/linux/acct.h>). It is
  234. up to the user level program to do useful things with this
  235. information. This is generally a good idea, so say Y.
  236. config BSD_PROCESS_ACCT_V3
  237. bool "BSD Process Accounting version 3 file format"
  238. depends on BSD_PROCESS_ACCT
  239. default n
  240. help
  241. If you say Y here, the process accounting information is written
  242. in a new file format that also logs the process IDs of each
  243. process and it's parent. Note that this file format is incompatible
  244. with previous v0/v1/v2 file formats, so you will need updated tools
  245. for processing it. A preliminary version of these tools is available
  246. at <http://www.gnu.org/software/acct/>.
  247. config FHANDLE
  248. bool "open by fhandle syscalls"
  249. select EXPORTFS
  250. help
  251. If you say Y here, a user level program will be able to map
  252. file names to handle and then later use the handle for
  253. different file system operations. This is useful in implementing
  254. userspace file servers, which now track files using handles instead
  255. of names. The handle would remain the same even if file names
  256. get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
  257. syscalls.
  258. config TASKSTATS
  259. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  260. depends on NET
  261. default n
  262. help
  263. Export selected statistics for tasks/processes through the
  264. generic netlink interface. Unlike BSD process accounting, the
  265. statistics are available during the lifetime of tasks/processes as
  266. responses to commands. Like BSD accounting, they are sent to user
  267. space on task exit.
  268. Say N if unsure.
  269. config TASK_DELAY_ACCT
  270. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  271. depends on TASKSTATS
  272. help
  273. Collect information on time spent by a task waiting for system
  274. resources like cpu, synchronous block I/O completion and swapping
  275. in pages. Such statistics can help in setting a task's priorities
  276. relative to other tasks for cpu, io, rss limits etc.
  277. Say N if unsure.
  278. config TASK_XACCT
  279. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  280. depends on TASKSTATS
  281. help
  282. Collect extended task accounting data and send the data
  283. to userland for processing over the taskstats interface.
  284. Say N if unsure.
  285. config TASK_IO_ACCOUNTING
  286. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  287. depends on TASK_XACCT
  288. help
  289. Collect information on the number of bytes of storage I/O which this
  290. task has caused.
  291. Say N if unsure.
  292. config AUDIT
  293. bool "Auditing support"
  294. depends on NET
  295. help
  296. Enable auditing infrastructure that can be used with another
  297. kernel subsystem, such as SELinux (which requires this for
  298. logging of avc messages output). Does not do system-call
  299. auditing without CONFIG_AUDITSYSCALL.
  300. config AUDITSYSCALL
  301. bool "Enable system-call auditing support"
  302. depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
  303. default y if SECURITY_SELINUX
  304. help
  305. Enable low-overhead system-call auditing infrastructure that
  306. can be used independently or with another kernel subsystem,
  307. such as SELinux.
  308. config AUDIT_WATCH
  309. def_bool y
  310. depends on AUDITSYSCALL
  311. select FSNOTIFY
  312. config AUDIT_TREE
  313. def_bool y
  314. depends on AUDITSYSCALL
  315. select FSNOTIFY
  316. config AUDIT_LOGINUID_IMMUTABLE
  317. bool "Make audit loginuid immutable"
  318. depends on AUDIT
  319. help
  320. The config option toggles if a task setting its loginuid requires
  321. CAP_SYS_AUDITCONTROL or if that task should require no special permissions
  322. but should instead only allow setting its loginuid if it was never
  323. previously set. On systems which use systemd or a similar central
  324. process to restart login services this should be set to true. On older
  325. systems in which an admin would typically have to directly stop and
  326. start processes this should be set to false. Setting this to true allows
  327. one to drop potentially dangerous capabilites from the login tasks,
  328. but may not be backwards compatible with older init systems.
  329. source "kernel/irq/Kconfig"
  330. source "kernel/time/Kconfig"
  331. menu "RCU Subsystem"
  332. choice
  333. prompt "RCU Implementation"
  334. default TREE_RCU
  335. config TREE_RCU
  336. bool "Tree-based hierarchical RCU"
  337. depends on !PREEMPT && SMP
  338. help
  339. This option selects the RCU implementation that is
  340. designed for very large SMP system with hundreds or
  341. thousands of CPUs. It also scales down nicely to
  342. smaller systems.
  343. config TREE_PREEMPT_RCU
  344. bool "Preemptible tree-based hierarchical RCU"
  345. depends on PREEMPT && SMP
  346. help
  347. This option selects the RCU implementation that is
  348. designed for very large SMP systems with hundreds or
  349. thousands of CPUs, but for which real-time response
  350. is also required. It also scales down nicely to
  351. smaller systems.
  352. config TINY_RCU
  353. bool "UP-only small-memory-footprint RCU"
  354. depends on !PREEMPT && !SMP
  355. help
  356. This option selects the RCU implementation that is
  357. designed for UP systems from which real-time response
  358. is not required. This option greatly reduces the
  359. memory footprint of RCU.
  360. config TINY_PREEMPT_RCU
  361. bool "Preemptible UP-only small-memory-footprint RCU"
  362. depends on PREEMPT && !SMP
  363. help
  364. This option selects the RCU implementation that is designed
  365. for real-time UP systems. This option greatly reduces the
  366. memory footprint of RCU.
  367. endchoice
  368. config PREEMPT_RCU
  369. def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
  370. help
  371. This option enables preemptible-RCU code that is common between
  372. the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
  373. config RCU_FANOUT
  374. int "Tree-based hierarchical RCU fanout value"
  375. range 2 64 if 64BIT
  376. range 2 32 if !64BIT
  377. depends on TREE_RCU || TREE_PREEMPT_RCU
  378. default 64 if 64BIT
  379. default 32 if !64BIT
  380. help
  381. This option controls the fanout of hierarchical implementations
  382. of RCU, allowing RCU to work efficiently on machines with
  383. large numbers of CPUs. This value must be at least the fourth
  384. root of NR_CPUS, which allows NR_CPUS to be insanely large.
  385. The default value of RCU_FANOUT should be used for production
  386. systems, but if you are stress-testing the RCU implementation
  387. itself, small RCU_FANOUT values allow you to test large-system
  388. code paths on small(er) systems.
  389. Select a specific number if testing RCU itself.
  390. Take the default if unsure.
  391. config RCU_FANOUT_LEAF
  392. int "Tree-based hierarchical RCU leaf-level fanout value"
  393. range 2 RCU_FANOUT if 64BIT
  394. range 2 RCU_FANOUT if !64BIT
  395. depends on TREE_RCU || TREE_PREEMPT_RCU
  396. default 16
  397. help
  398. This option controls the leaf-level fanout of hierarchical
  399. implementations of RCU, and allows trading off cache misses
  400. against lock contention. Systems that synchronize their
  401. scheduling-clock interrupts for energy-efficiency reasons will
  402. want the default because the smaller leaf-level fanout keeps
  403. lock contention levels acceptably low. Very large systems
  404. (hundreds or thousands of CPUs) will instead want to set this
  405. value to the maximum value possible in order to reduce the
  406. number of cache misses incurred during RCU's grace-period
  407. initialization. These systems tend to run CPU-bound, and thus
  408. are not helped by synchronized interrupts, and thus tend to
  409. skew them, which reduces lock contention enough that large
  410. leaf-level fanouts work well.
  411. Select a specific number if testing RCU itself.
  412. Select the maximum permissible value for large systems.
  413. Take the default if unsure.
  414. config RCU_FANOUT_EXACT
  415. bool "Disable tree-based hierarchical RCU auto-balancing"
  416. depends on TREE_RCU || TREE_PREEMPT_RCU
  417. default n
  418. help
  419. This option forces use of the exact RCU_FANOUT value specified,
  420. regardless of imbalances in the hierarchy. This is useful for
  421. testing RCU itself, and might one day be useful on systems with
  422. strong NUMA behavior.
  423. Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
  424. Say N if unsure.
  425. config RCU_FAST_NO_HZ
  426. bool "Accelerate last non-dyntick-idle CPU's grace periods"
  427. depends on NO_HZ && SMP
  428. default n
  429. help
  430. This option causes RCU to attempt to accelerate grace periods
  431. in order to allow CPUs to enter dynticks-idle state more
  432. quickly. On the other hand, this option increases the overhead
  433. of the dynticks-idle checking, particularly on systems with
  434. large numbers of CPUs.
  435. Say Y if energy efficiency is critically important, particularly
  436. if you have relatively few CPUs.
  437. Say N if you are unsure.
  438. config TREE_RCU_TRACE
  439. def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
  440. select DEBUG_FS
  441. help
  442. This option provides tracing for the TREE_RCU and
  443. TREE_PREEMPT_RCU implementations, permitting Makefile to
  444. trivially select kernel/rcutree_trace.c.
  445. config RCU_BOOST
  446. bool "Enable RCU priority boosting"
  447. depends on RT_MUTEXES && PREEMPT_RCU
  448. default n
  449. help
  450. This option boosts the priority of preempted RCU readers that
  451. block the current preemptible RCU grace period for too long.
  452. This option also prevents heavy loads from blocking RCU
  453. callback invocation for all flavors of RCU.
  454. Say Y here if you are working with real-time apps or heavy loads
  455. Say N here if you are unsure.
  456. config RCU_BOOST_PRIO
  457. int "Real-time priority to boost RCU readers to"
  458. range 1 99
  459. depends on RCU_BOOST
  460. default 1
  461. help
  462. This option specifies the real-time priority to which long-term
  463. preempted RCU readers are to be boosted. If you are working
  464. with a real-time application that has one or more CPU-bound
  465. threads running at a real-time priority level, you should set
  466. RCU_BOOST_PRIO to a priority higher then the highest-priority
  467. real-time CPU-bound thread. The default RCU_BOOST_PRIO value
  468. of 1 is appropriate in the common case, which is real-time
  469. applications that do not have any CPU-bound threads.
  470. Some real-time applications might not have a single real-time
  471. thread that saturates a given CPU, but instead might have
  472. multiple real-time threads that, taken together, fully utilize
  473. that CPU. In this case, you should set RCU_BOOST_PRIO to
  474. a priority higher than the lowest-priority thread that is
  475. conspiring to prevent the CPU from running any non-real-time
  476. tasks. For example, if one thread at priority 10 and another
  477. thread at priority 5 are between themselves fully consuming
  478. the CPU time on a given CPU, then RCU_BOOST_PRIO should be
  479. set to priority 6 or higher.
  480. Specify the real-time priority, or take the default if unsure.
  481. config RCU_BOOST_DELAY
  482. int "Milliseconds to delay boosting after RCU grace-period start"
  483. range 0 3000
  484. depends on RCU_BOOST
  485. default 500
  486. help
  487. This option specifies the time to wait after the beginning of
  488. a given grace period before priority-boosting preempted RCU
  489. readers blocking that grace period. Note that any RCU reader
  490. blocking an expedited RCU grace period is boosted immediately.
  491. Accept the default if unsure.
  492. endmenu # "RCU Subsystem"
  493. config IKCONFIG
  494. tristate "Kernel .config support"
  495. ---help---
  496. This option enables the complete Linux kernel ".config" file
  497. contents to be saved in the kernel. It provides documentation
  498. of which kernel options are used in a running kernel or in an
  499. on-disk kernel. This information can be extracted from the kernel
  500. image file with the script scripts/extract-ikconfig and used as
  501. input to rebuild the current kernel or to build another kernel.
  502. It can also be extracted from a running kernel by reading
  503. /proc/config.gz if enabled (below).
  504. config IKCONFIG_PROC
  505. bool "Enable access to .config through /proc/config.gz"
  506. depends on IKCONFIG && PROC_FS
  507. ---help---
  508. This option enables access to the kernel configuration file
  509. through /proc/config.gz.
  510. config LOG_BUF_SHIFT
  511. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  512. range 12 21
  513. default 17
  514. help
  515. Select kernel log buffer size as a power of 2.
  516. Examples:
  517. 17 => 128 KB
  518. 16 => 64 KB
  519. 15 => 32 KB
  520. 14 => 16 KB
  521. 13 => 8 KB
  522. 12 => 4 KB
  523. #
  524. # Architectures with an unreliable sched_clock() should select this:
  525. #
  526. config HAVE_UNSTABLE_SCHED_CLOCK
  527. bool
  528. menuconfig CGROUPS
  529. boolean "Control Group support"
  530. depends on EVENTFD
  531. help
  532. This option adds support for grouping sets of processes together, for
  533. use with process control subsystems such as Cpusets, CFS, memory
  534. controls or device isolation.
  535. See
  536. - Documentation/scheduler/sched-design-CFS.txt (CFS)
  537. - Documentation/cgroups/ (features for grouping, isolation
  538. and resource control)
  539. Say N if unsure.
  540. if CGROUPS
  541. config CGROUP_DEBUG
  542. bool "Example debug cgroup subsystem"
  543. default n
  544. help
  545. This option enables a simple cgroup subsystem that
  546. exports useful debugging information about the cgroups
  547. framework.
  548. Say N if unsure.
  549. config CGROUP_FREEZER
  550. bool "Freezer cgroup subsystem"
  551. help
  552. Provides a way to freeze and unfreeze all tasks in a
  553. cgroup.
  554. config CGROUP_DEVICE
  555. bool "Device controller for cgroups"
  556. help
  557. Provides a cgroup implementing whitelists for devices which
  558. a process in the cgroup can mknod or open.
  559. config CPUSETS
  560. bool "Cpuset support"
  561. help
  562. This option will let you create and manage CPUSETs which
  563. allow dynamically partitioning a system into sets of CPUs and
  564. Memory Nodes and assigning tasks to run only within those sets.
  565. This is primarily useful on large SMP or NUMA systems.
  566. Say N if unsure.
  567. config PROC_PID_CPUSET
  568. bool "Include legacy /proc/<pid>/cpuset file"
  569. depends on CPUSETS
  570. default y
  571. config CGROUP_CPUACCT
  572. bool "Simple CPU accounting cgroup subsystem"
  573. help
  574. Provides a simple Resource Controller for monitoring the
  575. total CPU consumed by the tasks in a cgroup.
  576. config RESOURCE_COUNTERS
  577. bool "Resource counters"
  578. help
  579. This option enables controller independent resource accounting
  580. infrastructure that works with cgroups.
  581. config CGROUP_MEM_RES_CTLR
  582. bool "Memory Resource Controller for Control Groups"
  583. depends on RESOURCE_COUNTERS
  584. select MM_OWNER
  585. help
  586. Provides a memory resource controller that manages both anonymous
  587. memory and page cache. (See Documentation/cgroups/memory.txt)
  588. Note that setting this option increases fixed memory overhead
  589. associated with each page of memory in the system. By this,
  590. 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
  591. usage tracking struct at boot. Total amount of this is printed out
  592. at boot.
  593. Only enable when you're ok with these trade offs and really
  594. sure you need the memory resource controller. Even when you enable
  595. this, you can set "cgroup_disable=memory" at your boot option to
  596. disable memory resource controller and you can avoid overheads.
  597. (and lose benefits of memory resource controller)
  598. This config option also selects MM_OWNER config option, which
  599. could in turn add some fork/exit overhead.
  600. config CGROUP_MEM_RES_CTLR_SWAP
  601. bool "Memory Resource Controller Swap Extension"
  602. depends on CGROUP_MEM_RES_CTLR && SWAP
  603. help
  604. Add swap management feature to memory resource controller. When you
  605. enable this, you can limit mem+swap usage per cgroup. In other words,
  606. when you disable this, memory resource controller has no cares to
  607. usage of swap...a process can exhaust all of the swap. This extension
  608. is useful when you want to avoid exhaustion swap but this itself
  609. adds more overheads and consumes memory for remembering information.
  610. Especially if you use 32bit system or small memory system, please
  611. be careful about enabling this. When memory resource controller
  612. is disabled by boot option, this will be automatically disabled and
  613. there will be no overhead from this. Even when you set this config=y,
  614. if boot option "swapaccount=0" is set, swap will not be accounted.
  615. Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
  616. size is 4096bytes, 512k per 1Gbytes of swap.
  617. config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  618. bool "Memory Resource Controller Swap Extension enabled by default"
  619. depends on CGROUP_MEM_RES_CTLR_SWAP
  620. default y
  621. help
  622. Memory Resource Controller Swap Extension comes with its price in
  623. a bigger memory consumption. General purpose distribution kernels
  624. which want to enable the feature but keep it disabled by default
  625. and let the user enable it by swapaccount boot command line
  626. parameter should have this option unselected.
  627. For those who want to have the feature enabled by default should
  628. select this option (if, for some reason, they need to disable it
  629. then swapaccount=0 does the trick).
  630. config CGROUP_MEM_RES_CTLR_KMEM
  631. bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
  632. depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
  633. default n
  634. help
  635. The Kernel Memory extension for Memory Resource Controller can limit
  636. the amount of memory used by kernel objects in the system. Those are
  637. fundamentally different from the entities handled by the standard
  638. Memory Controller, which are page-based, and can be swapped. Users of
  639. the kmem extension can use it to guarantee that no group of processes
  640. will ever exhaust kernel resources alone.
  641. config CGROUP_PERF
  642. bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
  643. depends on PERF_EVENTS && CGROUPS
  644. help
  645. This option extends the per-cpu mode to restrict monitoring to
  646. threads which belong to the cgroup specified and run on the
  647. designated cpu.
  648. Say N if unsure.
  649. menuconfig CGROUP_SCHED
  650. bool "Group CPU scheduler"
  651. default n
  652. help
  653. This feature lets CPU scheduler recognize task groups and control CPU
  654. bandwidth allocation to such task groups. It uses cgroups to group
  655. tasks.
  656. if CGROUP_SCHED
  657. config FAIR_GROUP_SCHED
  658. bool "Group scheduling for SCHED_OTHER"
  659. depends on CGROUP_SCHED
  660. default CGROUP_SCHED
  661. config CFS_BANDWIDTH
  662. bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
  663. depends on EXPERIMENTAL
  664. depends on FAIR_GROUP_SCHED
  665. default n
  666. help
  667. This option allows users to define CPU bandwidth rates (limits) for
  668. tasks running within the fair group scheduler. Groups with no limit
  669. set are considered to be unconstrained and will run with no
  670. restriction.
  671. See tip/Documentation/scheduler/sched-bwc.txt for more information.
  672. config RT_GROUP_SCHED
  673. bool "Group scheduling for SCHED_RR/FIFO"
  674. depends on EXPERIMENTAL
  675. depends on CGROUP_SCHED
  676. default n
  677. help
  678. This feature lets you explicitly allocate real CPU bandwidth
  679. to task groups. If enabled, it will also make it impossible to
  680. schedule realtime tasks for non-root users until you allocate
  681. realtime bandwidth for them.
  682. See Documentation/scheduler/sched-rt-group.txt for more information.
  683. endif #CGROUP_SCHED
  684. config BLK_CGROUP
  685. bool "Block IO controller"
  686. depends on BLOCK
  687. default n
  688. ---help---
  689. Generic block IO controller cgroup interface. This is the common
  690. cgroup interface which should be used by various IO controlling
  691. policies.
  692. Currently, CFQ IO scheduler uses it to recognize task groups and
  693. control disk bandwidth allocation (proportional time slice allocation)
  694. to such task groups. It is also used by bio throttling logic in
  695. block layer to implement upper limit in IO rates on a device.
  696. This option only enables generic Block IO controller infrastructure.
  697. One needs to also enable actual IO controlling logic/policy. For
  698. enabling proportional weight division of disk bandwidth in CFQ, set
  699. CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
  700. CONFIG_BLK_DEV_THROTTLING=y.
  701. See Documentation/cgroups/blkio-controller.txt for more information.
  702. config DEBUG_BLK_CGROUP
  703. bool "Enable Block IO controller debugging"
  704. depends on BLK_CGROUP
  705. default n
  706. ---help---
  707. Enable some debugging help. Currently it exports additional stat
  708. files in a cgroup which can be useful for debugging.
  709. endif # CGROUPS
  710. config CHECKPOINT_RESTORE
  711. bool "Checkpoint/restore support" if EXPERT
  712. default n
  713. help
  714. Enables additional kernel features in a sake of checkpoint/restore.
  715. In particular it adds auxiliary prctl codes to setup process text,
  716. data and heap segment sizes, and a few additional /proc filesystem
  717. entries.
  718. If unsure, say N here.
  719. menuconfig NAMESPACES
  720. bool "Namespaces support" if EXPERT
  721. default !EXPERT
  722. help
  723. Provides the way to make tasks work with different objects using
  724. the same id. For example same IPC id may refer to different objects
  725. or same user id or pid may refer to different tasks when used in
  726. different namespaces.
  727. if NAMESPACES
  728. config UTS_NS
  729. bool "UTS namespace"
  730. default y
  731. help
  732. In this namespace tasks see different info provided with the
  733. uname() system call
  734. config IPC_NS
  735. bool "IPC namespace"
  736. depends on (SYSVIPC || POSIX_MQUEUE)
  737. default y
  738. help
  739. In this namespace tasks work with IPC ids which correspond to
  740. different IPC objects in different namespaces.
  741. config USER_NS
  742. bool "User namespace (EXPERIMENTAL)"
  743. depends on EXPERIMENTAL
  744. depends on UIDGID_CONVERTED
  745. select UIDGID_STRICT_TYPE_CHECKS
  746. default n
  747. help
  748. This allows containers, i.e. vservers, to use user namespaces
  749. to provide different user info for different servers.
  750. If unsure, say N.
  751. config PID_NS
  752. bool "PID Namespaces"
  753. default y
  754. help
  755. Support process id namespaces. This allows having multiple
  756. processes with the same pid as long as they are in different
  757. pid namespaces. This is a building block of containers.
  758. config NET_NS
  759. bool "Network namespace"
  760. depends on NET
  761. default y
  762. help
  763. Allow user space to create what appear to be multiple instances
  764. of the network stack.
  765. endif # NAMESPACES
  766. config UIDGID_CONVERTED
  767. # True if all of the selected software conmponents are known
  768. # to have uid_t and gid_t converted to kuid_t and kgid_t
  769. # where appropriate and are otherwise safe to use with
  770. # the user namespace.
  771. bool
  772. default y
  773. # List of kernel pieces that need user namespace work
  774. # Features
  775. depends on SYSVIPC = n
  776. depends on IMA = n
  777. depends on EVM = n
  778. depends on KEYS = n
  779. depends on AUDIT = n
  780. depends on AUDITSYSCALL = n
  781. depends on TASKSTATS = n
  782. depends on TRACING = n
  783. depends on FS_POSIX_ACL = n
  784. depends on QUOTA = n
  785. depends on QUOTACTL = n
  786. depends on DEBUG_CREDENTIALS = n
  787. depends on BSD_PROCESS_ACCT = n
  788. depends on DRM = n
  789. depends on PROC_EVENTS = n
  790. # Networking
  791. depends on NET = n
  792. depends on NET_9P = n
  793. depends on IPX = n
  794. depends on PHONET = n
  795. depends on NET_CLS_FLOW = n
  796. depends on NETFILTER_XT_MATCH_OWNER = n
  797. depends on NETFILTER_XT_MATCH_RECENT = n
  798. depends on NETFILTER_XT_TARGET_LOG = n
  799. depends on NETFILTER_NETLINK_LOG = n
  800. depends on INET = n
  801. depends on IPV6 = n
  802. depends on IP_SCTP = n
  803. depends on AF_RXRPC = n
  804. depends on LLC2 = n
  805. depends on NET_KEY = n
  806. depends on INET_DIAG = n
  807. depends on DNS_RESOLVER = n
  808. depends on AX25 = n
  809. depends on ATALK = n
  810. # Filesystems
  811. depends on USB_DEVICEFS = n
  812. depends on USB_GADGETFS = n
  813. depends on USB_FUNCTIONFS = n
  814. depends on DEVTMPFS = n
  815. depends on XENFS = n
  816. depends on 9P_FS = n
  817. depends on ADFS_FS = n
  818. depends on AFFS_FS = n
  819. depends on AFS_FS = n
  820. depends on AUTOFS4_FS = n
  821. depends on BEFS_FS = n
  822. depends on BFS_FS = n
  823. depends on BTRFS_FS = n
  824. depends on CEPH_FS = n
  825. depends on CIFS = n
  826. depends on CODA_FS = n
  827. depends on CONFIGFS_FS = n
  828. depends on CRAMFS = n
  829. depends on DEBUG_FS = n
  830. depends on ECRYPT_FS = n
  831. depends on EFS_FS = n
  832. depends on EXOFS_FS = n
  833. depends on FAT_FS = n
  834. depends on FUSE_FS = n
  835. depends on GFS2_FS = n
  836. depends on HFS_FS = n
  837. depends on HFSPLUS_FS = n
  838. depends on HPFS_FS = n
  839. depends on HUGETLBFS = n
  840. depends on ISO9660_FS = n
  841. depends on JFFS2_FS = n
  842. depends on JFS_FS = n
  843. depends on LOGFS = n
  844. depends on MINIX_FS = n
  845. depends on NCP_FS = n
  846. depends on NFSD = n
  847. depends on NFS_FS = n
  848. depends on NILFS2_FS = n
  849. depends on NTFS_FS = n
  850. depends on OCFS2_FS = n
  851. depends on OMFS_FS = n
  852. depends on QNX4FS_FS = n
  853. depends on QNX6FS_FS = n
  854. depends on REISERFS_FS = n
  855. depends on SQUASHFS = n
  856. depends on SYSV_FS = n
  857. depends on UBIFS_FS = n
  858. depends on UDF_FS = n
  859. depends on UFS_FS = n
  860. depends on VXFS_FS = n
  861. depends on XFS_FS = n
  862. depends on !UML || HOSTFS = n
  863. # The rare drivers that won't build
  864. depends on AIRO = n
  865. depends on AIRO_CS = n
  866. depends on TUN = n
  867. depends on INFINIBAND_QIB = n
  868. depends on BLK_DEV_LOOP = n
  869. depends on ANDROID_BINDER_IPC = n
  870. # Security modules
  871. depends on SECURITY_TOMOYO = n
  872. depends on SECURITY_APPARMOR = n
  873. config UIDGID_STRICT_TYPE_CHECKS
  874. bool "Require conversions between uid/gids and their internal representation"
  875. depends on UIDGID_CONVERTED
  876. default n
  877. help
  878. While the nececessary conversions are being added to all subsystems this option allows
  879. the code to continue to build for unconverted subsystems.
  880. Say Y here if you want the strict type checking enabled
  881. config SCHED_AUTOGROUP
  882. bool "Automatic process group scheduling"
  883. select EVENTFD
  884. select CGROUPS
  885. select CGROUP_SCHED
  886. select FAIR_GROUP_SCHED
  887. help
  888. This option optimizes the scheduler for common desktop workloads by
  889. automatically creating and populating task groups. This separation
  890. of workloads isolates aggressive CPU burners (like build jobs) from
  891. desktop applications. Task group autogeneration is currently based
  892. upon task session.
  893. config MM_OWNER
  894. bool
  895. config SYSFS_DEPRECATED
  896. bool "Enable deprecated sysfs features to support old userspace tools"
  897. depends on SYSFS
  898. default n
  899. help
  900. This option adds code that switches the layout of the "block" class
  901. devices, to not show up in /sys/class/block/, but only in
  902. /sys/block/.
  903. This switch is only active when the sysfs.deprecated=1 boot option is
  904. passed or the SYSFS_DEPRECATED_V2 option is set.
  905. This option allows new kernels to run on old distributions and tools,
  906. which might get confused by /sys/class/block/. Since 2007/2008 all
  907. major distributions and tools handle this just fine.
  908. Recent distributions and userspace tools after 2009/2010 depend on
  909. the existence of /sys/class/block/, and will not work with this
  910. option enabled.
  911. Only if you are using a new kernel on an old distribution, you might
  912. need to say Y here.
  913. config SYSFS_DEPRECATED_V2
  914. bool "Enable deprecated sysfs features by default"
  915. default n
  916. depends on SYSFS
  917. depends on SYSFS_DEPRECATED
  918. help
  919. Enable deprecated sysfs by default.
  920. See the CONFIG_SYSFS_DEPRECATED option for more details about this
  921. option.
  922. Only if you are using a new kernel on an old distribution, you might
  923. need to say Y here. Even then, odds are you would not need it
  924. enabled, you can always pass the boot option if absolutely necessary.
  925. config RELAY
  926. bool "Kernel->user space relay support (formerly relayfs)"
  927. help
  928. This option enables support for relay interface support in
  929. certain file systems (such as debugfs).
  930. It is designed to provide an efficient mechanism for tools and
  931. facilities to relay large amounts of data from kernel space to
  932. user space.
  933. If unsure, say N.
  934. config BLK_DEV_INITRD
  935. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  936. depends on BROKEN || !FRV
  937. help
  938. The initial RAM filesystem is a ramfs which is loaded by the
  939. boot loader (loadlin or lilo) and that is mounted as root
  940. before the normal boot procedure. It is typically used to
  941. load modules needed to mount the "real" root file system,
  942. etc. See <file:Documentation/initrd.txt> for details.
  943. If RAM disk support (BLK_DEV_RAM) is also included, this
  944. also enables initial RAM disk (initrd) support and adds
  945. 15 Kbytes (more on some other architectures) to the kernel size.
  946. If unsure say Y.
  947. if BLK_DEV_INITRD
  948. source "usr/Kconfig"
  949. endif
  950. config CC_OPTIMIZE_FOR_SIZE
  951. bool "Optimize for size"
  952. help
  953. Enabling this option will pass "-Os" instead of "-O2" to gcc
  954. resulting in a smaller kernel.
  955. If unsure, say Y.
  956. config SYSCTL
  957. bool
  958. config ANON_INODES
  959. bool
  960. menuconfig EXPERT
  961. bool "Configure standard kernel features (expert users)"
  962. # Unhide debug options, to make the on-by-default options visible
  963. select DEBUG_KERNEL
  964. help
  965. This option allows certain base kernel options and settings
  966. to be disabled or tweaked. This is for specialized
  967. environments which can tolerate a "non-standard" kernel.
  968. Only use this if you really know what you are doing.
  969. config UID16
  970. bool "Enable 16-bit UID system calls" if EXPERT
  971. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
  972. default y
  973. help
  974. This enables the legacy 16-bit UID syscall wrappers.
  975. config SYSCTL_SYSCALL
  976. bool "Sysctl syscall support" if EXPERT
  977. depends on PROC_SYSCTL
  978. default n
  979. select SYSCTL
  980. ---help---
  981. sys_sysctl uses binary paths that have been found challenging
  982. to properly maintain and use. The interface in /proc/sys
  983. using paths with ascii names is now the primary path to this
  984. information.
  985. Almost nothing using the binary sysctl interface so if you are
  986. trying to save some space it is probably safe to disable this,
  987. making your kernel marginally smaller.
  988. If unsure say N here.
  989. config KALLSYMS
  990. bool "Load all symbols for debugging/ksymoops" if EXPERT
  991. default y
  992. help
  993. Say Y here to let the kernel print out symbolic crash information and
  994. symbolic stack backtraces. This increases the size of the kernel
  995. somewhat, as all symbols have to be loaded into the kernel image.
  996. config KALLSYMS_ALL
  997. bool "Include all symbols in kallsyms"
  998. depends on DEBUG_KERNEL && KALLSYMS
  999. help
  1000. Normally kallsyms only contains the symbols of functions for nicer
  1001. OOPS messages and backtraces (i.e., symbols from the text and inittext
  1002. sections). This is sufficient for most cases. And only in very rare
  1003. cases (e.g., when a debugger is used) all symbols are required (e.g.,
  1004. names of variables from the data sections, etc).
  1005. This option makes sure that all symbols are loaded into the kernel
  1006. image (i.e., symbols from all sections) in cost of increased kernel
  1007. size (depending on the kernel configuration, it may be 300KiB or
  1008. something like this).
  1009. Say N unless you really need all symbols.
  1010. config HOTPLUG
  1011. bool "Support for hot-pluggable devices" if EXPERT
  1012. default y
  1013. help
  1014. This option is provided for the case where no hotplug or uevent
  1015. capabilities is wanted by the kernel. You should only consider
  1016. disabling this option for embedded systems that do not use modules, a
  1017. dynamic /dev tree, or dynamic device discovery. Just say Y.
  1018. config PRINTK
  1019. default y
  1020. bool "Enable support for printk" if EXPERT
  1021. help
  1022. This option enables normal printk support. Removing it
  1023. eliminates most of the message strings from the kernel image
  1024. and makes the kernel more or less silent. As this makes it
  1025. very difficult to diagnose system problems, saying N here is
  1026. strongly discouraged.
  1027. config BUG
  1028. bool "BUG() support" if EXPERT
  1029. default y
  1030. help
  1031. Disabling this option eliminates support for BUG and WARN, reducing
  1032. the size of your kernel image and potentially quietly ignoring
  1033. numerous fatal conditions. You should only consider disabling this
  1034. option for embedded systems with no facilities for reporting errors.
  1035. Just say Y.
  1036. config ELF_CORE
  1037. default y
  1038. bool "Enable ELF core dumps" if EXPERT
  1039. help
  1040. Enable support for generating core dumps. Disabling saves about 4k.
  1041. config PCSPKR_PLATFORM
  1042. bool "Enable PC-Speaker support" if EXPERT
  1043. depends on HAVE_PCSPKR_PLATFORM
  1044. select I8253_LOCK
  1045. default y
  1046. help
  1047. This option allows to disable the internal PC-Speaker
  1048. support, saving some memory.
  1049. config HAVE_PCSPKR_PLATFORM
  1050. bool
  1051. config BASE_FULL
  1052. default y
  1053. bool "Enable full-sized data structures for core" if EXPERT
  1054. help
  1055. Disabling this option reduces the size of miscellaneous core
  1056. kernel data structures. This saves memory on small machines,
  1057. but may reduce performance.
  1058. config FUTEX
  1059. bool "Enable futex support" if EXPERT
  1060. default y
  1061. select RT_MUTEXES
  1062. help
  1063. Disabling this option will cause the kernel to be built without
  1064. support for "fast userspace mutexes". The resulting kernel may not
  1065. run glibc-based applications correctly.
  1066. config EPOLL
  1067. bool "Enable eventpoll support" if EXPERT
  1068. default y
  1069. select ANON_INODES
  1070. help
  1071. Disabling this option will cause the kernel to be built without
  1072. support for epoll family of system calls.
  1073. config SIGNALFD
  1074. bool "Enable signalfd() system call" if EXPERT
  1075. select ANON_INODES
  1076. default y
  1077. help
  1078. Enable the signalfd() system call that allows to receive signals
  1079. on a file descriptor.
  1080. If unsure, say Y.
  1081. config TIMERFD
  1082. bool "Enable timerfd() system call" if EXPERT
  1083. select ANON_INODES
  1084. default y
  1085. help
  1086. Enable the timerfd() system call that allows to receive timer
  1087. events on a file descriptor.
  1088. If unsure, say Y.
  1089. config EVENTFD
  1090. bool "Enable eventfd() system call" if EXPERT
  1091. select ANON_INODES
  1092. default y
  1093. help
  1094. Enable the eventfd() system call that allows to receive both
  1095. kernel notification (ie. KAIO) or userspace notifications.
  1096. If unsure, say Y.
  1097. config SHMEM
  1098. bool "Use full shmem filesystem" if EXPERT
  1099. default y
  1100. depends on MMU
  1101. help
  1102. The shmem is an internal filesystem used to manage shared memory.
  1103. It is backed by swap and manages resource limits. It is also exported
  1104. to userspace as tmpfs if TMPFS is enabled. Disabling this
  1105. option replaces shmem and tmpfs with the much simpler ramfs code,
  1106. which may be appropriate on small systems without swap.
  1107. config AIO
  1108. bool "Enable AIO support" if EXPERT
  1109. default y
  1110. help
  1111. This option enables POSIX asynchronous I/O which may by used
  1112. by some high performance threaded applications. Disabling
  1113. this option saves about 7k.
  1114. config EMBEDDED
  1115. bool "Embedded system"
  1116. select EXPERT
  1117. help
  1118. This option should be enabled if compiling the kernel for
  1119. an embedded system so certain expert options are available
  1120. for configuration.
  1121. config HAVE_PERF_EVENTS
  1122. bool
  1123. help
  1124. See tools/perf/design.txt for details.
  1125. config PERF_USE_VMALLOC
  1126. bool
  1127. help
  1128. See tools/perf/design.txt for details
  1129. menu "Kernel Performance Events And Counters"
  1130. config PERF_EVENTS
  1131. bool "Kernel performance events and counters"
  1132. default y if PROFILING
  1133. depends on HAVE_PERF_EVENTS
  1134. select ANON_INODES
  1135. select IRQ_WORK
  1136. help
  1137. Enable kernel support for various performance events provided
  1138. by software and hardware.
  1139. Software events are supported either built-in or via the
  1140. use of generic tracepoints.
  1141. Most modern CPUs support performance events via performance
  1142. counter registers. These registers count the number of certain
  1143. types of hw events: such as instructions executed, cachemisses
  1144. suffered, or branches mis-predicted - without slowing down the
  1145. kernel or applications. These registers can also trigger interrupts
  1146. when a threshold number of events have passed - and can thus be
  1147. used to profile the code that runs on that CPU.
  1148. The Linux Performance Event subsystem provides an abstraction of
  1149. these software and hardware event capabilities, available via a
  1150. system call and used by the "perf" utility in tools/perf/. It
  1151. provides per task and per CPU counters, and it provides event
  1152. capabilities on top of those.
  1153. Say Y if unsure.
  1154. config DEBUG_PERF_USE_VMALLOC
  1155. default n
  1156. bool "Debug: use vmalloc to back perf mmap() buffers"
  1157. depends on PERF_EVENTS && DEBUG_KERNEL
  1158. select PERF_USE_VMALLOC
  1159. help
  1160. Use vmalloc memory to back perf mmap() buffers.
  1161. Mostly useful for debugging the vmalloc code on platforms
  1162. that don't require it.
  1163. Say N if unsure.
  1164. endmenu
  1165. config VM_EVENT_COUNTERS
  1166. default y
  1167. bool "Enable VM event counters for /proc/vmstat" if EXPERT
  1168. help
  1169. VM event counters are needed for event counts to be shown.
  1170. This option allows the disabling of the VM event counters
  1171. on EXPERT systems. /proc/vmstat will only show page counts
  1172. if VM event counters are disabled.
  1173. config PCI_QUIRKS
  1174. default y
  1175. bool "Enable PCI quirk workarounds" if EXPERT
  1176. depends on PCI
  1177. help
  1178. This enables workarounds for various PCI chipset
  1179. bugs/quirks. Disable this only if your target machine is
  1180. unaffected by PCI quirks.
  1181. config SLUB_DEBUG
  1182. default y
  1183. bool "Enable SLUB debugging support" if EXPERT
  1184. depends on SLUB && SYSFS
  1185. help
  1186. SLUB has extensive debug support features. Disabling these can
  1187. result in significant savings in code size. This also disables
  1188. SLUB sysfs support. /sys/slab will not exist and there will be
  1189. no support for cache validation etc.
  1190. config COMPAT_BRK
  1191. bool "Disable heap randomization"
  1192. default y
  1193. help
  1194. Randomizing heap placement makes heap exploits harder, but it
  1195. also breaks ancient binaries (including anything libc5 based).
  1196. This option changes the bootup default to heap randomization
  1197. disabled, and can be overridden at runtime by setting
  1198. /proc/sys/kernel/randomize_va_space to 2.
  1199. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  1200. choice
  1201. prompt "Choose SLAB allocator"
  1202. default SLUB
  1203. help
  1204. This option allows to select a slab allocator.
  1205. config SLAB
  1206. bool "SLAB"
  1207. help
  1208. The regular slab allocator that is established and known to work
  1209. well in all environments. It organizes cache hot objects in
  1210. per cpu and per node queues.
  1211. config SLUB
  1212. bool "SLUB (Unqueued Allocator)"
  1213. help
  1214. SLUB is a slab allocator that minimizes cache line usage
  1215. instead of managing queues of cached objects (SLAB approach).
  1216. Per cpu caching is realized using slabs of objects instead
  1217. of queues of objects. SLUB can use memory efficiently
  1218. and has enhanced diagnostics. SLUB is the default choice for
  1219. a slab allocator.
  1220. config SLOB
  1221. depends on EXPERT
  1222. bool "SLOB (Simple Allocator)"
  1223. help
  1224. SLOB replaces the stock allocator with a drastically simpler
  1225. allocator. SLOB is generally more space efficient but
  1226. does not perform as well on large systems.
  1227. endchoice
  1228. config MMAP_ALLOW_UNINITIALIZED
  1229. bool "Allow mmapped anonymous memory to be uninitialized"
  1230. depends on EXPERT && !MMU
  1231. default n
  1232. help
  1233. Normally, and according to the Linux spec, anonymous memory obtained
  1234. from mmap() has it's contents cleared before it is passed to
  1235. userspace. Enabling this config option allows you to request that
  1236. mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
  1237. providing a huge performance boost. If this option is not enabled,
  1238. then the flag will be ignored.
  1239. This is taken advantage of by uClibc's malloc(), and also by
  1240. ELF-FDPIC binfmt's brk and stack allocator.
  1241. Because of the obvious security issues, this option should only be
  1242. enabled on embedded devices where you control what is run in
  1243. userspace. Since that isn't generally a problem on no-MMU systems,
  1244. it is normally safe to say Y here.
  1245. See Documentation/nommu-mmap.txt for more information.
  1246. config PROFILING
  1247. bool "Profiling support"
  1248. help
  1249. Say Y here to enable the extended profiling support mechanisms used
  1250. by profilers such as OProfile.
  1251. #
  1252. # Place an empty function call at each tracepoint site. Can be
  1253. # dynamically changed for a probe function.
  1254. #
  1255. config TRACEPOINTS
  1256. bool
  1257. source "arch/Kconfig"
  1258. endmenu # General setup
  1259. config HAVE_GENERIC_DMA_COHERENT
  1260. bool
  1261. default n
  1262. config SLABINFO
  1263. bool
  1264. depends on PROC_FS
  1265. depends on SLAB || SLUB_DEBUG
  1266. default y
  1267. config RT_MUTEXES
  1268. boolean
  1269. config BASE_SMALL
  1270. int
  1271. default 0 if BASE_FULL
  1272. default 1 if !BASE_FULL
  1273. menuconfig MODULES
  1274. bool "Enable loadable module support"
  1275. help
  1276. Kernel modules are small pieces of compiled code which can
  1277. be inserted in the running kernel, rather than being
  1278. permanently built into the kernel. You use the "modprobe"
  1279. tool to add (and sometimes remove) them. If you say Y here,
  1280. many parts of the kernel can be built as modules (by
  1281. answering M instead of Y where indicated): this is most
  1282. useful for infrequently used options which are not required
  1283. for booting. For more information, see the man pages for
  1284. modprobe, lsmod, modinfo, insmod and rmmod.
  1285. If you say Y here, you will need to run "make
  1286. modules_install" to put the modules under /lib/modules/
  1287. where modprobe can find them (you may need to be root to do
  1288. this).
  1289. If unsure, say Y.
  1290. if MODULES
  1291. config MODULE_FORCE_LOAD
  1292. bool "Forced module loading"
  1293. default n
  1294. help
  1295. Allow loading of modules without version information (ie. modprobe
  1296. --force). Forced module loading sets the 'F' (forced) taint flag and
  1297. is usually a really bad idea.
  1298. config MODULE_UNLOAD
  1299. bool "Module unloading"
  1300. help
  1301. Without this option you will not be able to unload any
  1302. modules (note that some modules may not be unloadable
  1303. anyway), which makes your kernel smaller, faster
  1304. and simpler. If unsure, say Y.
  1305. config MODULE_FORCE_UNLOAD
  1306. bool "Forced module unloading"
  1307. depends on MODULE_UNLOAD && EXPERIMENTAL
  1308. help
  1309. This option allows you to force a module to unload, even if the
  1310. kernel believes it is unsafe: the kernel will remove the module
  1311. without waiting for anyone to stop using it (using the -f option to
  1312. rmmod). This is mainly for kernel developers and desperate users.
  1313. If unsure, say N.
  1314. config MODVERSIONS
  1315. bool "Module versioning support"
  1316. help
  1317. Usually, you have to use modules compiled with your kernel.
  1318. Saying Y here makes it sometimes possible to use modules
  1319. compiled for different kernels, by adding enough information
  1320. to the modules to (hopefully) spot any changes which would
  1321. make them incompatible with the kernel you are running. If
  1322. unsure, say N.
  1323. config MODULE_SRCVERSION_ALL
  1324. bool "Source checksum for all modules"
  1325. help
  1326. Modules which contain a MODULE_VERSION get an extra "srcversion"
  1327. field inserted into their modinfo section, which contains a
  1328. sum of the source files which made it. This helps maintainers
  1329. see exactly which source was used to build a module (since
  1330. others sometimes change the module source without updating
  1331. the version). With this option, such a "srcversion" field
  1332. will be created for all modules. If unsure, say N.
  1333. endif # MODULES
  1334. config INIT_ALL_POSSIBLE
  1335. bool
  1336. help
  1337. Back when each arch used to define their own cpu_online_mask and
  1338. cpu_possible_mask, some of them chose to initialize cpu_possible_mask
  1339. with all 1s, and others with all 0s. When they were centralised,
  1340. it was better to provide this option than to break all the archs
  1341. and have several arch maintainers pursuing me down dark alleys.
  1342. config STOP_MACHINE
  1343. bool
  1344. default y
  1345. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  1346. help
  1347. Need stop_machine() primitive.
  1348. source "block/Kconfig"
  1349. config PREEMPT_NOTIFIERS
  1350. bool
  1351. config PADATA
  1352. depends on SMP
  1353. bool
  1354. source "kernel/Kconfig.locks"