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. menu "General setup"
  25. config EXPERIMENTAL
  26. bool "Prompt for development and/or incomplete code/drivers"
  27. ---help---
  28. Some of the various things that Linux supports (such as network
  29. drivers, file systems, network protocols, etc.) can be in a state
  30. of development where the functionality, stability, or the level of
  31. testing is not yet high enough for general use. This is usually
  32. known as the "alpha-test" phase among developers. If a feature is
  33. currently in alpha-test, then the developers usually discourage
  34. uninformed widespread use of this feature by the general public to
  35. avoid "Why doesn't this work?" type mail messages. However, active
  36. testing and use of these systems is welcomed. Just be aware that it
  37. may not meet the normal level of reliability or it may fail to work
  38. in some special cases. Detailed bug reports from people familiar
  39. with the kernel internals are usually welcomed by the developers
  40. (before submitting bug reports, please read the documents
  41. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  42. <file:Documentation/BUG-HUNTING>, and
  43. <file:Documentation/oops-tracing.txt> in the kernel source).
  44. This option will also make obsoleted drivers available. These are
  45. drivers that have been replaced by something else, and/or are
  46. scheduled to be removed in a future kernel release.
  47. Unless you intend to help test and develop a feature or driver that
  48. falls into this category, or you have a situation that requires
  49. using these features, you should probably say N here, which will
  50. cause the configurator to present you with fewer choices. If
  51. you say Y here, you will be offered the choice of using features or
  52. drivers that are currently considered to be in the alpha-test phase.
  53. config BROKEN
  54. bool
  55. config BROKEN_ON_SMP
  56. bool
  57. depends on BROKEN || !SMP
  58. default y
  59. config INIT_ENV_ARG_LIMIT
  60. int
  61. default 32 if !UML
  62. default 128 if UML
  63. help
  64. Maximum of each of the number of arguments and environment
  65. variables passed to init from the kernel command line.
  66. config CROSS_COMPILE
  67. string "Cross-compiler tool prefix"
  68. help
  69. Same as running 'make CROSS_COMPILE=prefix-' but stored for
  70. default make runs in this kernel build directory. You don't
  71. need to set this unless you want the configured kernel build
  72. directory to select the cross-compiler automatically.
  73. config LOCALVERSION
  74. string "Local version - append to kernel release"
  75. help
  76. Append an extra string to the end of your kernel version.
  77. This will show up when you type uname, for example.
  78. The string you set here will be appended after the contents of
  79. any files with a filename matching localversion* in your
  80. object and source tree, in that order. Your total string can
  81. be a maximum of 64 characters.
  82. config LOCALVERSION_AUTO
  83. bool "Automatically append version information to the version string"
  84. default y
  85. help
  86. This will try to automatically determine if the current tree is a
  87. release tree by looking for git tags that belong to the current
  88. top of tree revision.
  89. A string of the format -gxxxxxxxx will be added to the localversion
  90. if a git-based tree is found. The string generated by this will be
  91. appended after any matching localversion* files, and after the value
  92. set in CONFIG_LOCALVERSION.
  93. (The actual string used here is the first eight characters produced
  94. by running the command:
  95. $ git rev-parse --verify HEAD
  96. which is done within the script "scripts/setlocalversion".)
  97. config HAVE_KERNEL_GZIP
  98. bool
  99. config HAVE_KERNEL_BZIP2
  100. bool
  101. config HAVE_KERNEL_LZMA
  102. bool
  103. config HAVE_KERNEL_XZ
  104. bool
  105. config HAVE_KERNEL_LZO
  106. bool
  107. config HAVE_KERNEL_LZ4
  108. bool
  109. choice
  110. prompt "Kernel compression mode"
  111. default KERNEL_GZIP
  112. depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
  113. help
  114. The linux kernel is a kind of self-extracting executable.
  115. Several compression algorithms are available, which differ
  116. in efficiency, compression and decompression speed.
  117. Compression speed is only relevant when building a kernel.
  118. Decompression speed is relevant at each boot.
  119. If you have any problems with bzip2 or lzma compressed
  120. kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
  121. version of this functionality (bzip2 only), for 2.4, was
  122. supplied by Christian Ludwig)
  123. High compression options are mostly useful for users, who
  124. are low on disk space (embedded systems), but for whom ram
  125. size matters less.
  126. If in doubt, select 'gzip'
  127. config KERNEL_GZIP
  128. bool "Gzip"
  129. depends on HAVE_KERNEL_GZIP
  130. help
  131. The old and tried gzip compression. It provides a good balance
  132. between compression ratio and decompression speed.
  133. config KERNEL_BZIP2
  134. bool "Bzip2"
  135. depends on HAVE_KERNEL_BZIP2
  136. help
  137. Its compression ratio and speed is intermediate.
  138. Decompression speed is slowest among the three. The kernel
  139. size is about 10% smaller with bzip2, in comparison to gzip.
  140. Bzip2 uses a large amount of memory. For modern kernels you
  141. will need at least 8MB RAM or more for booting.
  142. config KERNEL_LZMA
  143. bool "LZMA"
  144. depends on HAVE_KERNEL_LZMA
  145. help
  146. The most recent compression algorithm.
  147. Its ratio is best, decompression speed is between the other
  148. two. Compression is slowest. The kernel size is about 33%
  149. smaller with LZMA in comparison to gzip.
  150. config KERNEL_XZ
  151. bool "XZ"
  152. depends on HAVE_KERNEL_XZ
  153. help
  154. XZ uses the LZMA2 algorithm and instruction set specific
  155. BCJ filters which can improve compression ratio of executable
  156. code. The size of the kernel is about 30% smaller with XZ in
  157. comparison to gzip. On architectures for which there is a BCJ
  158. filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
  159. will create a few percent smaller kernel than plain LZMA.
  160. The speed is about the same as with LZMA: The decompression
  161. speed of XZ is better than that of bzip2 but worse than gzip
  162. and LZO. Compression is slow.
  163. config KERNEL_LZO
  164. bool "LZO"
  165. depends on HAVE_KERNEL_LZO
  166. help
  167. Its compression ratio is the poorest among the 4. The kernel
  168. size is about 10% bigger than gzip; however its speed
  169. (both compression and decompression) is the fastest.
  170. config KERNEL_LZ4
  171. bool "LZ4"
  172. depends on HAVE_KERNEL_LZ4
  173. help
  174. LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
  175. A preliminary version of LZ4 de/compression tool is available at
  176. <https://code.google.com/p/lz4/>.
  177. Its compression ratio is worse than LZO. The size of the kernel
  178. is about 8% bigger than LZO. But the decompression speed is
  179. faster than LZO.
  180. endchoice
  181. config DEFAULT_HOSTNAME
  182. string "Default hostname"
  183. default "(none)"
  184. help
  185. This option determines the default system hostname before userspace
  186. calls sethostname(2). The kernel traditionally uses "(none)" here,
  187. but you may wish to use a different default here to make a minimal
  188. system more usable with less configuration.
  189. config SWAP
  190. bool "Support for paging of anonymous memory (swap)"
  191. depends on MMU && BLOCK
  192. default y
  193. help
  194. This option allows you to choose whether you want to have support
  195. for so called swap devices or swap files in your kernel that are
  196. used to provide more virtual memory than the actual RAM present
  197. in your computer. If unsure say Y.
  198. config SYSVIPC
  199. bool "System V IPC"
  200. ---help---
  201. Inter Process Communication is a suite of library functions and
  202. system calls which let processes (running programs) synchronize and
  203. exchange information. It is generally considered to be a good thing,
  204. and some programs won't run unless you say Y here. In particular, if
  205. you want to run the DOS emulator dosemu under Linux (read the
  206. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  207. you'll need to say Y here.
  208. You can find documentation about IPC with "info ipc" and also in
  209. section 6.4 of the Linux Programmer's Guide, available from
  210. <http://www.tldp.org/guides.html>.
  211. config SYSVIPC_SYSCTL
  212. bool
  213. depends on SYSVIPC
  214. depends on SYSCTL
  215. default y
  216. config POSIX_MQUEUE
  217. bool "POSIX Message Queues"
  218. depends on NET && EXPERIMENTAL
  219. ---help---
  220. POSIX variant of message queues is a part of IPC. In POSIX message
  221. queues every message has a priority which decides about succession
  222. of receiving it by a process. If you want to compile and run
  223. programs written e.g. for Solaris with use of its POSIX message
  224. queues (functions mq_*) say Y here.
  225. POSIX message queues are visible as a filesystem called 'mqueue'
  226. and can be mounted somewhere if you want to do filesystem
  227. operations on message queues.
  228. If unsure, say Y.
  229. config POSIX_MQUEUE_SYSCTL
  230. bool
  231. depends on POSIX_MQUEUE
  232. depends on SYSCTL
  233. default y
  234. config BSD_PROCESS_ACCT
  235. bool "BSD Process Accounting"
  236. help
  237. If you say Y here, a user level program will be able to instruct the
  238. kernel (via a special system call) to write process accounting
  239. information to a file: whenever a process exits, information about
  240. that process will be appended to the file by the kernel. The
  241. information includes things such as creation time, owning user,
  242. command name, memory usage, controlling terminal etc. (the complete
  243. list is in the struct acct in <file:include/linux/acct.h>). It is
  244. up to the user level program to do useful things with this
  245. information. This is generally a good idea, so say Y.
  246. config BSD_PROCESS_ACCT_V3
  247. bool "BSD Process Accounting version 3 file format"
  248. depends on BSD_PROCESS_ACCT
  249. default n
  250. help
  251. If you say Y here, the process accounting information is written
  252. in a new file format that also logs the process IDs of each
  253. process and it's parent. Note that this file format is incompatible
  254. with previous v0/v1/v2 file formats, so you will need updated tools
  255. for processing it. A preliminary version of these tools is available
  256. at <http://www.gnu.org/software/acct/>.
  257. config FHANDLE
  258. bool "open by fhandle syscalls"
  259. select EXPORTFS
  260. help
  261. If you say Y here, a user level program will be able to map
  262. file names to handle and then later use the handle for
  263. different file system operations. This is useful in implementing
  264. userspace file servers, which now track files using handles instead
  265. of names. The handle would remain the same even if file names
  266. get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
  267. syscalls.
  268. config TASKSTATS
  269. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  270. depends on NET
  271. default n
  272. help
  273. Export selected statistics for tasks/processes through the
  274. generic netlink interface. Unlike BSD process accounting, the
  275. statistics are available during the lifetime of tasks/processes as
  276. responses to commands. Like BSD accounting, they are sent to user
  277. space on task exit.
  278. Say N if unsure.
  279. config TASK_DELAY_ACCT
  280. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  281. depends on TASKSTATS
  282. help
  283. Collect information on time spent by a task waiting for system
  284. resources like cpu, synchronous block I/O completion and swapping
  285. in pages. Such statistics can help in setting a task's priorities
  286. relative to other tasks for cpu, io, rss limits etc.
  287. Say N if unsure.
  288. config TASK_XACCT
  289. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  290. depends on TASKSTATS
  291. help
  292. Collect extended task accounting data and send the data
  293. to userland for processing over the taskstats interface.
  294. Say N if unsure.
  295. config TASK_IO_ACCOUNTING
  296. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  297. depends on TASK_XACCT
  298. help
  299. Collect information on the number of bytes of storage I/O which this
  300. task has caused.
  301. Say N if unsure.
  302. config AUDIT
  303. bool "Auditing support"
  304. depends on NET
  305. help
  306. Enable auditing infrastructure that can be used with another
  307. kernel subsystem, such as SELinux (which requires this for
  308. logging of avc messages output). Does not do system-call
  309. auditing without CONFIG_AUDITSYSCALL.
  310. config AUDITSYSCALL
  311. bool "Enable system-call auditing support"
  312. depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
  313. default y if SECURITY_SELINUX
  314. help
  315. Enable low-overhead system-call auditing infrastructure that
  316. can be used independently or with another kernel subsystem,
  317. such as SELinux.
  318. config AUDIT_WATCH
  319. def_bool y
  320. depends on AUDITSYSCALL
  321. select FSNOTIFY
  322. config AUDIT_TREE
  323. def_bool y
  324. depends on AUDITSYSCALL
  325. select FSNOTIFY
  326. config AUDIT_LOGINUID_IMMUTABLE
  327. bool "Make audit loginuid immutable"
  328. depends on AUDIT
  329. help
  330. The config option toggles if a task setting its loginuid requires
  331. CAP_SYS_AUDITCONTROL or if that task should require no special permissions
  332. but should instead only allow setting its loginuid if it was never
  333. previously set. On systems which use systemd or a similar central
  334. process to restart login services this should be set to true. On older
  335. systems in which an admin would typically have to directly stop and
  336. start processes this should be set to false. Setting this to true allows
  337. one to drop potentially dangerous capabilites from the login tasks,
  338. but may not be backwards compatible with older init systems.
  339. source "kernel/irq/Kconfig"
  340. menu "RCU Subsystem"
  341. choice
  342. prompt "RCU Implementation"
  343. default TREE_RCU
  344. config TREE_RCU
  345. bool "Tree-based hierarchical RCU"
  346. depends on !PREEMPT && SMP
  347. help
  348. This option selects the RCU implementation that is
  349. designed for very large SMP system with hundreds or
  350. thousands of CPUs. It also scales down nicely to
  351. smaller systems.
  352. config TREE_PREEMPT_RCU
  353. bool "Preemptible tree-based hierarchical RCU"
  354. depends on PREEMPT && SMP
  355. help
  356. This option selects the RCU implementation that is
  357. designed for very large SMP systems with hundreds or
  358. thousands of CPUs, but for which real-time response
  359. is also required. It also scales down nicely to
  360. smaller systems.
  361. config TINY_RCU
  362. bool "UP-only small-memory-footprint RCU"
  363. depends on !PREEMPT && !SMP
  364. help
  365. This option selects the RCU implementation that is
  366. designed for UP systems from which real-time response
  367. is not required. This option greatly reduces the
  368. memory footprint of RCU.
  369. config TINY_PREEMPT_RCU
  370. bool "Preemptible UP-only small-memory-footprint RCU"
  371. depends on PREEMPT && !SMP
  372. help
  373. This option selects the RCU implementation that is designed
  374. for real-time UP systems. This option greatly reduces the
  375. memory footprint of RCU.
  376. endchoice
  377. config PREEMPT_RCU
  378. def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
  379. help
  380. This option enables preemptible-RCU code that is common between
  381. the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
  382. config RCU_FANOUT
  383. int "Tree-based hierarchical RCU fanout value"
  384. range 2 64 if 64BIT
  385. range 2 32 if !64BIT
  386. depends on TREE_RCU || TREE_PREEMPT_RCU
  387. default 64 if 64BIT
  388. default 32 if !64BIT
  389. help
  390. This option controls the fanout of hierarchical implementations
  391. of RCU, allowing RCU to work efficiently on machines with
  392. large numbers of CPUs. This value must be at least the fourth
  393. root of NR_CPUS, which allows NR_CPUS to be insanely large.
  394. The default value of RCU_FANOUT should be used for production
  395. systems, but if you are stress-testing the RCU implementation
  396. itself, small RCU_FANOUT values allow you to test large-system
  397. code paths on small(er) systems.
  398. Select a specific number if testing RCU itself.
  399. Take the default if unsure.
  400. config RCU_FANOUT_EXACT
  401. bool "Disable tree-based hierarchical RCU auto-balancing"
  402. depends on TREE_RCU || TREE_PREEMPT_RCU
  403. default n
  404. help
  405. This option forces use of the exact RCU_FANOUT value specified,
  406. regardless of imbalances in the hierarchy. This is useful for
  407. testing RCU itself, and might one day be useful on systems with
  408. strong NUMA behavior.
  409. Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
  410. Say N if unsure.
  411. config RCU_FAST_NO_HZ
  412. bool "Accelerate last non-dyntick-idle CPU's grace periods"
  413. depends on NO_HZ && SMP && !SEC_FACTORY
  414. default n
  415. help
  416. This option causes RCU to attempt to accelerate grace periods
  417. in order to allow CPUs to enter dynticks-idle state more
  418. quickly. On the other hand, this option increases the overhead
  419. of the dynticks-idle checking, particularly on systems with
  420. large numbers of CPUs.
  421. Say Y if energy efficiency is critically important, particularly
  422. if you have relatively few CPUs.
  423. Say N if you are unsure.
  424. config RCU_FAST_NO_HZ_OFF_AT_BOOT
  425. bool "turn off rcu_fast_no_hz concept at boot time"
  426. depends on RCU_FAST_NO_HZ
  427. default n
  428. config TREE_RCU_TRACE
  429. def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
  430. select DEBUG_FS
  431. help
  432. This option provides tracing for the TREE_RCU and
  433. TREE_PREEMPT_RCU implementations, permitting Makefile to
  434. trivially select kernel/rcutree_trace.c.
  435. config RCU_BOOST
  436. bool "Enable RCU priority boosting"
  437. depends on RT_MUTEXES && PREEMPT_RCU
  438. default n
  439. help
  440. This option boosts the priority of preempted RCU readers that
  441. block the current preemptible RCU grace period for too long.
  442. This option also prevents heavy loads from blocking RCU
  443. callback invocation for all flavors of RCU.
  444. Say Y here if you are working with real-time apps or heavy loads
  445. Say N here if you are unsure.
  446. config RCU_BOOST_PRIO
  447. int "Real-time priority to boost RCU readers to"
  448. range 1 99
  449. depends on RCU_BOOST
  450. default 1
  451. help
  452. This option specifies the real-time priority to which preempted
  453. RCU readers are to be boosted. If you are working with CPU-bound
  454. real-time applications, you should specify a priority higher then
  455. the highest-priority CPU-bound application.
  456. Specify the real-time priority, or take the default if unsure.
  457. config RCU_BOOST_DELAY
  458. int "Milliseconds to delay boosting after RCU grace-period start"
  459. range 0 3000
  460. depends on RCU_BOOST
  461. default 500
  462. help
  463. This option specifies the time to wait after the beginning of
  464. a given grace period before priority-boosting preempted RCU
  465. readers blocking that grace period. Note that any RCU reader
  466. blocking an expedited RCU grace period is boosted immediately.
  467. Accept the default if unsure.
  468. endmenu # "RCU Subsystem"
  469. config BUILD_BIN2C
  470. bool
  471. default n
  472. config IKCONFIG
  473. tristate "Kernel .config support"
  474. select BUILD_BIN2C
  475. ---help---
  476. This option enables the complete Linux kernel ".config" file
  477. contents to be saved in the kernel. It provides documentation
  478. of which kernel options are used in a running kernel or in an
  479. on-disk kernel. This information can be extracted from the kernel
  480. image file with the script scripts/extract-ikconfig and used as
  481. input to rebuild the current kernel or to build another kernel.
  482. It can also be extracted from a running kernel by reading
  483. /proc/config.gz if enabled (below).
  484. config IKCONFIG_PROC
  485. bool "Enable access to .config through /proc/config.gz"
  486. depends on IKCONFIG && PROC_FS
  487. ---help---
  488. This option enables access to the kernel configuration file
  489. through /proc/config.gz.
  490. config LOG_BUF_SHIFT
  491. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  492. range 12 21
  493. default 17
  494. depends on PRINTK
  495. help
  496. Select kernel log buffer size as a power of 2.
  497. Examples:
  498. 17 => 128 KB
  499. 16 => 64 KB
  500. 15 => 32 KB
  501. 14 => 16 KB
  502. 13 => 8 KB
  503. 12 => 4 KB
  504. #
  505. # Architectures with an unreliable sched_clock() should select this:
  506. #
  507. config HAVE_UNSTABLE_SCHED_CLOCK
  508. bool
  509. config GENERIC_SCHED_CLOCK
  510. bool
  511. menuconfig CGROUPS
  512. boolean "Control Group support"
  513. depends on EVENTFD
  514. help
  515. This option adds support for grouping sets of processes together, for
  516. use with process control subsystems such as Cpusets, CFS, memory
  517. controls or device isolation.
  518. See
  519. - Documentation/scheduler/sched-design-CFS.txt (CFS)
  520. - Documentation/cgroups/ (features for grouping, isolation
  521. and resource control)
  522. Say N if unsure.
  523. if CGROUPS
  524. config CGROUP_DEBUG
  525. bool "Example debug cgroup subsystem"
  526. default n
  527. help
  528. This option enables a simple cgroup subsystem that
  529. exports useful debugging information about the cgroups
  530. framework.
  531. Say N if unsure.
  532. config CGROUP_FREEZER
  533. bool "Freezer cgroup subsystem"
  534. help
  535. Provides a way to freeze and unfreeze all tasks in a
  536. cgroup.
  537. config CGROUP_DEVICE
  538. bool "Device controller for cgroups"
  539. help
  540. Provides a cgroup implementing whitelists for devices which
  541. a process in the cgroup can mknod or open.
  542. config CPUSETS
  543. bool "Cpuset support"
  544. help
  545. This option will let you create and manage CPUSETs which
  546. allow dynamically partitioning a system into sets of CPUs and
  547. Memory Nodes and assigning tasks to run only within those sets.
  548. This is primarily useful on large SMP or NUMA systems.
  549. Say N if unsure.
  550. config PROC_PID_CPUSET
  551. bool "Include legacy /proc/<pid>/cpuset file"
  552. depends on CPUSETS
  553. default y
  554. config CGROUP_CPUACCT
  555. bool "Simple CPU accounting cgroup subsystem"
  556. help
  557. Provides a simple Resource Controller for monitoring the
  558. total CPU consumed by the tasks in a cgroup.
  559. config RESOURCE_COUNTERS
  560. bool "Resource counters"
  561. help
  562. This option enables controller independent resource accounting
  563. infrastructure that works with cgroups.
  564. config MEMCG
  565. bool "Memory Resource Controller for Control Groups"
  566. depends on RESOURCE_COUNTERS
  567. select MM_OWNER
  568. help
  569. Provides a memory resource controller that manages both anonymous
  570. memory and page cache. (See Documentation/cgroups/memory.txt)
  571. Note that setting this option increases fixed memory overhead
  572. associated with each page of memory in the system. By this,
  573. 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
  574. usage tracking struct at boot. Total amount of this is printed out
  575. at boot.
  576. Only enable when you're ok with these trade offs and really
  577. sure you need the memory resource controller. Even when you enable
  578. this, you can set "cgroup_disable=memory" at your boot option to
  579. disable memory resource controller and you can avoid overheads.
  580. (and lose benefits of memory resource controller)
  581. This config option also selects MM_OWNER config option, which
  582. could in turn add some fork/exit overhead.
  583. config MEMCG_SWAP
  584. bool "Memory Resource Controller Swap Extension"
  585. depends on MEMCG && SWAP
  586. help
  587. Add swap management feature to memory resource controller. When you
  588. enable this, you can limit mem+swap usage per cgroup. In other words,
  589. when you disable this, memory resource controller has no cares to
  590. usage of swap...a process can exhaust all of the swap. This extension
  591. is useful when you want to avoid exhaustion swap but this itself
  592. adds more overheads and consumes memory for remembering information.
  593. Especially if you use 32bit system or small memory system, please
  594. be careful about enabling this. When memory resource controller
  595. is disabled by boot option, this will be automatically disabled and
  596. there will be no overhead from this. Even when you set this config=y,
  597. if boot option "swapaccount=0" is set, swap will not be accounted.
  598. Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
  599. size is 4096bytes, 512k per 1Gbytes of swap.
  600. config MEMCG_SWAP_ENABLED
  601. bool "Memory Resource Controller Swap Extension enabled by default"
  602. depends on MEMCG_SWAP
  603. default y
  604. help
  605. Memory Resource Controller Swap Extension comes with its price in
  606. a bigger memory consumption. General purpose distribution kernels
  607. which want to enable the feature but keep it disabled by default
  608. and let the user enable it by swapaccount boot command line
  609. parameter should have this option unselected.
  610. For those who want to have the feature enabled by default should
  611. select this option (if, for some reason, they need to disable it
  612. then swapaccount=0 does the trick).
  613. config MEMCG_KMEM
  614. bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
  615. depends on MEMCG && EXPERIMENTAL
  616. default n
  617. help
  618. The Kernel Memory extension for Memory Resource Controller can limit
  619. the amount of memory used by kernel objects in the system. Those are
  620. fundamentally different from the entities handled by the standard
  621. Memory Controller, which are page-based, and can be swapped. Users of
  622. the kmem extension can use it to guarantee that no group of processes
  623. will ever exhaust kernel resources alone.
  624. config CGROUP_PERF
  625. bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
  626. depends on PERF_EVENTS && CGROUPS
  627. help
  628. This option extends the per-cpu mode to restrict monitoring to
  629. threads which belong to the cgroup specified and run on the
  630. designated cpu.
  631. Say N if unsure.
  632. menuconfig CGROUP_SCHED
  633. bool "Group CPU scheduler"
  634. default n
  635. help
  636. This feature lets CPU scheduler recognize task groups and control CPU
  637. bandwidth allocation to such task groups. It uses cgroups to group
  638. tasks.
  639. if CGROUP_SCHED
  640. config FAIR_GROUP_SCHED
  641. bool "Group scheduling for SCHED_OTHER"
  642. depends on CGROUP_SCHED
  643. default CGROUP_SCHED
  644. config CFS_BANDWIDTH
  645. bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
  646. depends on EXPERIMENTAL
  647. depends on FAIR_GROUP_SCHED
  648. default n
  649. help
  650. This option allows users to define CPU bandwidth rates (limits) for
  651. tasks running within the fair group scheduler. Groups with no limit
  652. set are considered to be unconstrained and will run with no
  653. restriction.
  654. See tip/Documentation/scheduler/sched-bwc.txt for more information.
  655. config RT_GROUP_SCHED
  656. bool "Group scheduling for SCHED_RR/FIFO"
  657. depends on EXPERIMENTAL
  658. depends on CGROUP_SCHED
  659. default n
  660. help
  661. This feature lets you explicitly allocate real CPU bandwidth
  662. to task groups. If enabled, it will also make it impossible to
  663. schedule realtime tasks for non-root users until you allocate
  664. realtime bandwidth for them.
  665. See Documentation/scheduler/sched-rt-group.txt for more information.
  666. endif #CGROUP_SCHED
  667. config BLK_CGROUP
  668. tristate "Block IO controller"
  669. depends on BLOCK
  670. default n
  671. ---help---
  672. Generic block IO controller cgroup interface. This is the common
  673. cgroup interface which should be used by various IO controlling
  674. policies.
  675. Currently, CFQ IO scheduler uses it to recognize task groups and
  676. control disk bandwidth allocation (proportional time slice allocation)
  677. to such task groups. It is also used by bio throttling logic in
  678. block layer to implement upper limit in IO rates on a device.
  679. This option only enables generic Block IO controller infrastructure.
  680. One needs to also enable actual IO controlling logic/policy. For
  681. enabling proportional weight division of disk bandwidth in CFQ, set
  682. CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
  683. CONFIG_BLK_DEV_THROTTLING=y.
  684. See Documentation/cgroups/blkio-controller.txt for more information.
  685. config DEBUG_BLK_CGROUP
  686. bool "Enable Block IO controller debugging"
  687. depends on BLK_CGROUP
  688. default n
  689. ---help---
  690. Enable some debugging help. Currently it exports additional stat
  691. files in a cgroup which can be useful for debugging.
  692. endif # CGROUPS
  693. config CHECKPOINT_RESTORE
  694. bool "Checkpoint/restore support" if EXPERT
  695. default n
  696. help
  697. Enables additional kernel features in a sake of checkpoint/restore.
  698. In particular it adds auxiliary prctl codes to setup process text,
  699. data and heap segment sizes, and a few additional /proc filesystem
  700. entries.
  701. If unsure, say N here.
  702. menuconfig NAMESPACES
  703. bool "Namespaces support" if EXPERT
  704. default !EXPERT
  705. help
  706. Provides the way to make tasks work with different objects using
  707. the same id. For example same IPC id may refer to different objects
  708. or same user id or pid may refer to different tasks when used in
  709. different namespaces.
  710. if NAMESPACES
  711. config UTS_NS
  712. bool "UTS namespace"
  713. default y
  714. help
  715. In this namespace tasks see different info provided with the
  716. uname() system call
  717. config IPC_NS
  718. bool "IPC namespace"
  719. depends on (SYSVIPC || POSIX_MQUEUE)
  720. default y
  721. help
  722. In this namespace tasks work with IPC ids which correspond to
  723. different IPC objects in different namespaces.
  724. config USER_NS
  725. bool "User namespace (EXPERIMENTAL)"
  726. depends on EXPERIMENTAL
  727. depends on UIDGID_CONVERTED
  728. select UIDGID_STRICT_TYPE_CHECKS
  729. default n
  730. help
  731. This allows containers, i.e. vservers, to use user namespaces
  732. to provide different user info for different servers.
  733. When user namespaces are enabled in the kernel it is
  734. recommended that the MEMCG and MEMCG_KMEM options also be
  735. enabled and that user-space use the memory control groups to
  736. limit the amount of memory a memory unprivileged users can
  737. use.
  738. If unsure, say N.
  739. config PID_NS
  740. bool "PID Namespaces"
  741. default y
  742. help
  743. Support process id namespaces. This allows having multiple
  744. processes with the same pid as long as they are in different
  745. pid namespaces. This is a building block of containers.
  746. config NET_NS
  747. bool "Network namespace"
  748. depends on NET
  749. default y
  750. help
  751. Allow user space to create what appear to be multiple instances
  752. of the network stack.
  753. endif # NAMESPACES
  754. config UIDGID_CONVERTED
  755. # True if all of the selected software conmponents are known
  756. # to have uid_t and gid_t converted to kuid_t and kgid_t
  757. # where appropriate and are otherwise safe to use with
  758. # the user namespace.
  759. bool
  760. default y
  761. # List of kernel pieces that need user namespace work
  762. # Features
  763. depends on BINFMT_ELF = n
  764. depends on BINFMT_ELF_FDPIC = n
  765. depends on UNIX98_PTYS = n
  766. depends on CGROUPS = n
  767. depends on MIGRATION = n
  768. depends on NUMA = n
  769. depends on IMA = n
  770. depends on EVM = n
  771. depends on KEYS = n
  772. depends on AUDIT = n
  773. depends on AUDITSYSCALL = n
  774. depends on TASKSTATS = n
  775. depends on TRACING = n
  776. depends on FS_POSIX_ACL = n
  777. depends on QUOTA = n
  778. depends on QUOTACTL = n
  779. depends on DEBUG_CREDENTIALS = n
  780. depends on BSD_PROCESS_ACCT = n
  781. depends on DRM = n
  782. depends on PROC_EVENTS = n
  783. # Networking
  784. depends on NET = n
  785. depends on NET_9P = n
  786. depends on IPX = n
  787. depends on PHONET = n
  788. depends on NET_CLS_FLOW = n
  789. depends on NETFILTER_XT_MATCH_OWNER = n
  790. depends on NETFILTER_XT_MATCH_RECENT = n
  791. depends on NETFILTER_XT_TARGET_LOG = n
  792. depends on NETFILTER_NETLINK_LOG = n
  793. depends on INET = n
  794. depends on IPV6 = n
  795. depends on IP_SCTP = n
  796. depends on AF_RXRPC = n
  797. depends on LLC2 = n
  798. depends on NET_KEY = n
  799. depends on INET_DIAG = n
  800. depends on DNS_RESOLVER = n
  801. depends on AX25 = n
  802. depends on ATALK = n
  803. # Filesystems
  804. depends on USB_DEVICEFS = n
  805. depends on USB_GADGETFS = n
  806. depends on USB_FUNCTIONFS = n
  807. depends on DEVTMPFS = n
  808. depends on XENFS = n
  809. depends on 9P_FS = n
  810. depends on ADFS_FS = n
  811. depends on AFFS_FS = n
  812. depends on AFS_FS = n
  813. depends on AUTOFS4_FS = n
  814. depends on BEFS_FS = n
  815. depends on BFS_FS = n
  816. depends on BTRFS_FS = n
  817. depends on CEPH_FS = n
  818. depends on CIFS = n
  819. depends on CODA_FS = n
  820. depends on CONFIGFS_FS = n
  821. depends on CRAMFS = n
  822. depends on DEBUG_FS = n
  823. depends on ECRYPT_FS = n
  824. depends on EFS_FS = n
  825. depends on EXOFS_FS = n
  826. depends on EXT2_FS = n
  827. depends on EXT3_FS = n
  828. depends on EXT4_FS = n
  829. depends on FAT_FS = n
  830. depends on FUSE_FS = n
  831. depends on GFS2_FS = n
  832. depends on HFS_FS = n
  833. depends on HFSPLUS_FS = n
  834. depends on HPFS_FS = n
  835. depends on HUGETLBFS = n
  836. depends on ISO9660_FS = n
  837. depends on JFFS2_FS = n
  838. depends on JFS_FS = n
  839. depends on LOGFS = n
  840. depends on MINIX_FS = n
  841. depends on NCP_FS = n
  842. depends on NFSD = n
  843. depends on NFS_FS = n
  844. depends on NILFS2_FS = n
  845. depends on NTFS_FS = n
  846. depends on OCFS2_FS = n
  847. depends on OMFS_FS = n
  848. depends on PROC_SYSCTL = n
  849. depends on QNX4FS_FS = n
  850. depends on QNX6FS_FS = n
  851. depends on REISERFS_FS = n
  852. depends on SQUASHFS = n
  853. depends on SYSFS = n
  854. depends on SYSV_FS = n
  855. depends on TMPFS = n
  856. depends on UBIFS_FS = n
  857. depends on UDF_FS = n
  858. depends on UFS_FS = n
  859. depends on VXFS_FS = n
  860. depends on XFS_FS = n
  861. depends on !UML || HOSTFS = n
  862. # The rare drivers that won't build
  863. depends on AIRO = n
  864. depends on AIRO_CS = n
  865. depends on TUN = n
  866. depends on INFINIBAND_QIB = n
  867. depends on BLK_DEV_LOOP = n
  868. depends on ANDROID_BINDER_IPC = n
  869. # Security modules
  870. depends on SECURITY_TOMOYO = n
  871. depends on SECURITY_APPARMOR = n
  872. config UIDGID_STRICT_TYPE_CHECKS
  873. bool "Require conversions between uid/gids and their internal representation"
  874. depends on UIDGID_CONVERTED
  875. default n
  876. help
  877. While the nececessary conversions are being added to all subsystems this option allows
  878. the code to continue to build for unconverted subsystems.
  879. Say Y here if you want the strict type checking enabled
  880. config SCHED_AUTOGROUP
  881. bool "Automatic process group scheduling"
  882. select EVENTFD
  883. select CGROUPS
  884. select CGROUP_SCHED
  885. select FAIR_GROUP_SCHED
  886. help
  887. This option optimizes the scheduler for common desktop workloads by
  888. automatically creating and populating task groups. This separation
  889. of workloads isolates aggressive CPU burners (like build jobs) from
  890. desktop applications. Task group autogeneration is currently based
  891. upon task session.
  892. config MM_OWNER
  893. bool
  894. config SYSFS_DEPRECATED
  895. bool "Enable deprecated sysfs features to support old userspace tools"
  896. depends on SYSFS
  897. default n
  898. help
  899. This option adds code that switches the layout of the "block" class
  900. devices, to not show up in /sys/class/block/, but only in
  901. /sys/block/.
  902. This switch is only active when the sysfs.deprecated=1 boot option is
  903. passed or the SYSFS_DEPRECATED_V2 option is set.
  904. This option allows new kernels to run on old distributions and tools,
  905. which might get confused by /sys/class/block/. Since 2007/2008 all
  906. major distributions and tools handle this just fine.
  907. Recent distributions and userspace tools after 2009/2010 depend on
  908. the existence of /sys/class/block/, and will not work with this
  909. option enabled.
  910. Only if you are using a new kernel on an old distribution, you might
  911. need to say Y here.
  912. config SYSFS_DEPRECATED_V2
  913. bool "Enable deprecated sysfs features by default"
  914. default n
  915. depends on SYSFS
  916. depends on SYSFS_DEPRECATED
  917. help
  918. Enable deprecated sysfs by default.
  919. See the CONFIG_SYSFS_DEPRECATED option for more details about this
  920. option.
  921. Only if you are using a new kernel on an old distribution, you might
  922. need to say Y here. Even then, odds are you would not need it
  923. enabled, you can always pass the boot option if absolutely necessary.
  924. config RELAY
  925. bool "Kernel->user space relay support (formerly relayfs)"
  926. help
  927. This option enables support for relay interface support in
  928. certain file systems (such as debugfs).
  929. It is designed to provide an efficient mechanism for tools and
  930. facilities to relay large amounts of data from kernel space to
  931. user space.
  932. If unsure, say N.
  933. config BLK_DEV_INITRD
  934. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  935. depends on BROKEN || !FRV
  936. help
  937. The initial RAM filesystem is a ramfs which is loaded by the
  938. boot loader (loadlin or lilo) and that is mounted as root
  939. before the normal boot procedure. It is typically used to
  940. load modules needed to mount the "real" root file system,
  941. etc. See <file:Documentation/initrd.txt> for details.
  942. If RAM disk support (BLK_DEV_RAM) is also included, this
  943. also enables initial RAM disk (initrd) support and adds
  944. 15 Kbytes (more on some other architectures) to the kernel size.
  945. If unsure say Y.
  946. if BLK_DEV_INITRD
  947. source "usr/Kconfig"
  948. endif
  949. config CC_OPTIMIZE_FOR_SIZE
  950. bool "Optimize for size"
  951. help
  952. Enabling this option will pass "-Os" instead of "-O2" to gcc
  953. resulting in a smaller kernel.
  954. If unsure, say Y.
  955. config SYSCTL
  956. bool
  957. config ANON_INODES
  958. bool
  959. config PANIC_TIMEOUT
  960. int "Default panic timeout"
  961. default 0
  962. help
  963. Set default panic timeout.
  964. menuconfig EXPERT
  965. bool "Configure standard kernel features (expert users)"
  966. # Unhide debug options, to make the on-by-default options visible
  967. select DEBUG_KERNEL
  968. help
  969. This option allows certain base kernel options and settings
  970. to be disabled or tweaked. This is for specialized
  971. environments which can tolerate a "non-standard" kernel.
  972. Only use this if you really know what you are doing.
  973. config UID16
  974. bool "Enable 16-bit UID system calls" if EXPERT
  975. depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
  976. default y
  977. help
  978. This enables the legacy 16-bit UID syscall wrappers.
  979. config SYSCTL_SYSCALL
  980. bool "Sysctl syscall support" if EXPERT
  981. depends on PROC_SYSCTL
  982. default n
  983. select SYSCTL
  984. ---help---
  985. sys_sysctl uses binary paths that have been found challenging
  986. to properly maintain and use. The interface in /proc/sys
  987. using paths with ascii names is now the primary path to this
  988. information.
  989. Almost nothing using the binary sysctl interface so if you are
  990. trying to save some space it is probably safe to disable this,
  991. making your kernel marginally smaller.
  992. If unsure say N here.
  993. config KALLSYMS
  994. bool "Load all symbols for debugging/ksymoops" if EXPERT
  995. default y
  996. help
  997. Say Y here to let the kernel print out symbolic crash information and
  998. symbolic stack backtraces. This increases the size of the kernel
  999. somewhat, as all symbols have to be loaded into the kernel image.
  1000. config KALLSYMS_ALL
  1001. bool "Include all symbols in kallsyms"
  1002. depends on DEBUG_KERNEL && KALLSYMS
  1003. help
  1004. Normally kallsyms only contains the symbols of functions for nicer
  1005. OOPS messages and backtraces (i.e., symbols from the text and inittext
  1006. sections). This is sufficient for most cases. And only in very rare
  1007. cases (e.g., when a debugger is used) all symbols are required (e.g.,
  1008. names of variables from the data sections, etc).
  1009. This option makes sure that all symbols are loaded into the kernel
  1010. image (i.e., symbols from all sections) in cost of increased kernel
  1011. size (depending on the kernel configuration, it may be 300KiB or
  1012. something like this).
  1013. Say N unless you really need all symbols.
  1014. config HOTPLUG
  1015. bool "Support for hot-pluggable devices" if EXPERT
  1016. default y
  1017. help
  1018. This option is provided for the case where no hotplug or uevent
  1019. capabilities is wanted by the kernel. You should only consider
  1020. disabling this option for embedded systems that do not use modules, a
  1021. dynamic /dev tree, or dynamic device discovery. Just say Y.
  1022. config PRINTK
  1023. default y
  1024. bool "Enable support for printk" if EXPERT
  1025. help
  1026. This option enables normal printk support. Removing it
  1027. eliminates most of the message strings from the kernel image
  1028. and makes the kernel more or less silent. As this makes it
  1029. very difficult to diagnose system problems, saying N here is
  1030. strongly discouraged.
  1031. config BUG
  1032. bool "BUG() support" if EXPERT
  1033. default y
  1034. help
  1035. Disabling this option eliminates support for BUG and WARN, reducing
  1036. the size of your kernel image and potentially quietly ignoring
  1037. numerous fatal conditions. You should only consider disabling this
  1038. option for embedded systems with no facilities for reporting errors.
  1039. Just say Y.
  1040. config ELF_CORE
  1041. default y
  1042. bool "Enable ELF core dumps" if EXPERT
  1043. help
  1044. Enable support for generating core dumps. Disabling saves about 4k.
  1045. config PCSPKR_PLATFORM
  1046. bool "Enable PC-Speaker support" if EXPERT
  1047. depends on HAVE_PCSPKR_PLATFORM
  1048. select I8253_LOCK
  1049. default y
  1050. help
  1051. This option allows to disable the internal PC-Speaker
  1052. support, saving some memory.
  1053. config HAVE_PCSPKR_PLATFORM
  1054. bool
  1055. config BASE_FULL
  1056. default y
  1057. bool "Enable full-sized data structures for core" if EXPERT
  1058. help
  1059. Disabling this option reduces the size of miscellaneous core
  1060. kernel data structures. This saves memory on small machines,
  1061. but may reduce performance.
  1062. config FUTEX
  1063. bool "Enable futex support" if EXPERT
  1064. default y
  1065. select RT_MUTEXES
  1066. help
  1067. Disabling this option will cause the kernel to be built without
  1068. support for "fast userspace mutexes". The resulting kernel may not
  1069. run glibc-based applications correctly.
  1070. config EPOLL
  1071. bool "Enable eventpoll support" if EXPERT
  1072. default y
  1073. select ANON_INODES
  1074. help
  1075. Disabling this option will cause the kernel to be built without
  1076. support for epoll family of system calls.
  1077. config SIGNALFD
  1078. bool "Enable signalfd() system call" if EXPERT
  1079. select ANON_INODES
  1080. default y
  1081. help
  1082. Enable the signalfd() system call that allows to receive signals
  1083. on a file descriptor.
  1084. If unsure, say Y.
  1085. config TIMERFD
  1086. bool "Enable timerfd() system call" if EXPERT
  1087. select ANON_INODES
  1088. default y
  1089. help
  1090. Enable the timerfd() system call that allows to receive timer
  1091. events on a file descriptor.
  1092. If unsure, say Y.
  1093. config EVENTFD
  1094. bool "Enable eventfd() system call" if EXPERT
  1095. select ANON_INODES
  1096. default y
  1097. help
  1098. Enable the eventfd() system call that allows to receive both
  1099. kernel notification (ie. KAIO) or userspace notifications.
  1100. If unsure, say Y.
  1101. config SHMEM
  1102. bool "Use full shmem filesystem" if EXPERT
  1103. default y
  1104. depends on MMU
  1105. help
  1106. The shmem is an internal filesystem used to manage shared memory.
  1107. It is backed by swap and manages resource limits. It is also exported
  1108. to userspace as tmpfs if TMPFS is enabled. Disabling this
  1109. option replaces shmem and tmpfs with the much simpler ramfs code,
  1110. which may be appropriate on small systems without swap.
  1111. config AIO
  1112. bool "Enable AIO support" if EXPERT
  1113. default y
  1114. help
  1115. This option enables POSIX asynchronous I/O which may by used
  1116. by some high performance threaded applications. Disabling
  1117. this option saves about 7k.
  1118. config EMBEDDED
  1119. bool "Embedded system"
  1120. select EXPERT
  1121. help
  1122. This option should be enabled if compiling the kernel for
  1123. an embedded system so certain expert options are available
  1124. for configuration.
  1125. config HAVE_PERF_EVENTS
  1126. bool
  1127. help
  1128. See tools/perf/design.txt for details.
  1129. config PERF_USE_VMALLOC
  1130. bool
  1131. help
  1132. See tools/perf/design.txt for details
  1133. menu "Kernel Performance Events And Counters"
  1134. config PERF_EVENTS
  1135. bool "Kernel performance events and counters"
  1136. default y if (PROFILING || PERF_COUNTERS)
  1137. depends on HAVE_PERF_EVENTS
  1138. select ANON_INODES
  1139. select IRQ_WORK
  1140. help
  1141. Enable kernel support for various performance events provided
  1142. by software and hardware.
  1143. Software events are supported either built-in or via the
  1144. use of generic tracepoints.
  1145. Most modern CPUs support performance events via performance
  1146. counter registers. These registers count the number of certain
  1147. types of hw events: such as instructions executed, cachemisses
  1148. suffered, or branches mis-predicted - without slowing down the
  1149. kernel or applications. These registers can also trigger interrupts
  1150. when a threshold number of events have passed - and can thus be
  1151. used to profile the code that runs on that CPU.
  1152. The Linux Performance Event subsystem provides an abstraction of
  1153. these software and hardware event capabilities, available via a
  1154. system call and used by the "perf" utility in tools/perf/. It
  1155. provides per task and per CPU counters, and it provides event
  1156. capabilities on top of those.
  1157. Say Y if unsure.
  1158. config PERF_COUNTERS
  1159. bool "Kernel performance counters (old config option)"
  1160. depends on HAVE_PERF_EVENTS
  1161. help
  1162. This config has been obsoleted by the PERF_EVENTS
  1163. config option - please see that one for details.
  1164. It has no effect on the kernel whether you enable
  1165. it or not, it is a compatibility placeholder.
  1166. Say N if unsure.
  1167. config DEBUG_PERF_USE_VMALLOC
  1168. default n
  1169. bool "Debug: use vmalloc to back perf mmap() buffers"
  1170. depends on PERF_EVENTS && DEBUG_KERNEL
  1171. select PERF_USE_VMALLOC
  1172. help
  1173. Use vmalloc memory to back perf mmap() buffers.
  1174. Mostly useful for debugging the vmalloc code on platforms
  1175. that don't require it.
  1176. Say N if unsure.
  1177. endmenu
  1178. config VM_EVENT_COUNTERS
  1179. default y
  1180. bool "Enable VM event counters for /proc/vmstat" if EXPERT
  1181. help
  1182. VM event counters are needed for event counts to be shown.
  1183. This option allows the disabling of the VM event counters
  1184. on EXPERT systems. /proc/vmstat will only show page counts
  1185. if VM event counters are disabled.
  1186. config PCI_QUIRKS
  1187. default y
  1188. bool "Enable PCI quirk workarounds" if EXPERT
  1189. depends on PCI
  1190. help
  1191. This enables workarounds for various PCI chipset
  1192. bugs/quirks. Disable this only if your target machine is
  1193. unaffected by PCI quirks.
  1194. config SLUB_DEBUG
  1195. default y
  1196. bool "Enable SLUB debugging support" if EXPERT
  1197. depends on SLUB && SYSFS
  1198. help
  1199. SLUB has extensive debug support features. Disabling these can
  1200. result in significant savings in code size. This also disables
  1201. SLUB sysfs support. /sys/slab will not exist and there will be
  1202. no support for cache validation etc.
  1203. config COMPAT_BRK
  1204. bool "Disable heap randomization"
  1205. default y
  1206. help
  1207. Randomizing heap placement makes heap exploits harder, but it
  1208. also breaks ancient binaries (including anything libc5 based).
  1209. This option changes the bootup default to heap randomization
  1210. disabled, and can be overridden at runtime by setting
  1211. /proc/sys/kernel/randomize_va_space to 2.
  1212. On non-ancient distros (post-2000 ones) N is usually a safe choice.
  1213. choice
  1214. prompt "Choose SLAB allocator"
  1215. default SLUB
  1216. help
  1217. This option allows to select a slab allocator.
  1218. config SLAB
  1219. bool "SLAB"
  1220. help
  1221. The regular slab allocator that is established and known to work
  1222. well in all environments. It organizes cache hot objects in
  1223. per cpu and per node queues.
  1224. config SLUB
  1225. depends on BROKEN || NUMA || !DISCONTIGMEM
  1226. bool "SLUB (Unqueued Allocator)"
  1227. help
  1228. SLUB is a slab allocator that minimizes cache line usage
  1229. instead of managing queues of cached objects (SLAB approach).
  1230. Per cpu caching is realized using slabs of objects instead
  1231. of queues of objects. SLUB can use memory efficiently
  1232. and has enhanced diagnostics. SLUB is the default choice for
  1233. a slab allocator.
  1234. config SLOB
  1235. depends on EXPERT
  1236. bool "SLOB (Simple Allocator)"
  1237. help
  1238. SLOB replaces the stock allocator with a drastically simpler
  1239. allocator. SLOB is generally more space efficient but
  1240. does not perform as well on large systems.
  1241. endchoice
  1242. config MMAP_ALLOW_UNINITIALIZED
  1243. bool "Allow mmapped anonymous memory to be uninitialized"
  1244. depends on EXPERT && !MMU
  1245. default n
  1246. help
  1247. Normally, and according to the Linux spec, anonymous memory obtained
  1248. from mmap() has it's contents cleared before it is passed to
  1249. userspace. Enabling this config option allows you to request that
  1250. mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
  1251. providing a huge performance boost. If this option is not enabled,
  1252. then the flag will be ignored.
  1253. This is taken advantage of by uClibc's malloc(), and also by
  1254. ELF-FDPIC binfmt's brk and stack allocator.
  1255. Because of the obvious security issues, this option should only be
  1256. enabled on embedded devices where you control what is run in
  1257. userspace. Since that isn't generally a problem on no-MMU systems,
  1258. it is normally safe to say Y here.
  1259. See Documentation/nommu-mmap.txt for more information.
  1260. config DEFERRED_INITCALLS
  1261. bool "Deferred initcalls support"
  1262. default n
  1263. help
  1264. Say 'y' here to include support for deferred initcalls
  1265. config PROFILING
  1266. bool "Profiling support"
  1267. help
  1268. Say Y here to enable the extended profiling support mechanisms used
  1269. by profilers such as OProfile.
  1270. #
  1271. # Place an empty function call at each tracepoint site. Can be
  1272. # dynamically changed for a probe function.
  1273. #
  1274. config TRACEPOINTS
  1275. bool
  1276. source "arch/Kconfig"
  1277. endmenu # General setup
  1278. config HAVE_GENERIC_DMA_COHERENT
  1279. bool
  1280. default n
  1281. config SLABINFO
  1282. bool
  1283. depends on PROC_FS
  1284. depends on SLAB || SLUB_DEBUG
  1285. default y
  1286. config RT_MUTEXES
  1287. boolean
  1288. config BASE_SMALL
  1289. int
  1290. default 0 if BASE_FULL
  1291. default 1 if !BASE_FULL
  1292. menuconfig MODULES
  1293. bool "Enable loadable module support"
  1294. help
  1295. Kernel modules are small pieces of compiled code which can
  1296. be inserted in the running kernel, rather than being
  1297. permanently built into the kernel. You use the "modprobe"
  1298. tool to add (and sometimes remove) them. If you say Y here,
  1299. many parts of the kernel can be built as modules (by
  1300. answering M instead of Y where indicated): this is most
  1301. useful for infrequently used options which are not required
  1302. for booting. For more information, see the man pages for
  1303. modprobe, lsmod, modinfo, insmod and rmmod.
  1304. If you say Y here, you will need to run "make
  1305. modules_install" to put the modules under /lib/modules/
  1306. where modprobe can find them (you may need to be root to do
  1307. this).
  1308. If unsure, say Y.
  1309. if MODULES
  1310. config MODULE_FORCE_LOAD
  1311. bool "Forced module loading"
  1312. default n
  1313. help
  1314. Allow loading of modules without version information (ie. modprobe
  1315. --force). Forced module loading sets the 'F' (forced) taint flag and
  1316. is usually a really bad idea.
  1317. config MODULE_UNLOAD
  1318. bool "Module unloading"
  1319. help
  1320. Without this option you will not be able to unload any
  1321. modules (note that some modules may not be unloadable
  1322. anyway), which makes your kernel smaller, faster
  1323. and simpler. If unsure, say Y.
  1324. config MODULE_FORCE_UNLOAD
  1325. bool "Forced module unloading"
  1326. depends on MODULE_UNLOAD && EXPERIMENTAL
  1327. help
  1328. This option allows you to force a module to unload, even if the
  1329. kernel believes it is unsafe: the kernel will remove the module
  1330. without waiting for anyone to stop using it (using the -f option to
  1331. rmmod). This is mainly for kernel developers and desperate users.
  1332. If unsure, say N.
  1333. config MODVERSIONS
  1334. bool "Module versioning support"
  1335. help
  1336. Usually, you have to use modules compiled with your kernel.
  1337. Saying Y here makes it sometimes possible to use modules
  1338. compiled for different kernels, by adding enough information
  1339. to the modules to (hopefully) spot any changes which would
  1340. make them incompatible with the kernel you are running. If
  1341. unsure, say N.
  1342. config MODULE_SRCVERSION_ALL
  1343. bool "Source checksum for all modules"
  1344. help
  1345. Modules which contain a MODULE_VERSION get an extra "srcversion"
  1346. field inserted into their modinfo section, which contains a
  1347. sum of the source files which made it. This helps maintainers
  1348. see exactly which source was used to build a module (since
  1349. others sometimes change the module source without updating
  1350. the version). With this option, such a "srcversion" field
  1351. will be created for all modules. If unsure, say N.
  1352. config TRIM_UNUSED_KSYMS
  1353. bool "Trim unused exported kernel symbols"
  1354. depends on MODULES && !UNUSED_SYMBOLS
  1355. help
  1356. The kernel and some modules make many symbols available for
  1357. other modules to use via EXPORT_SYMBOL() and variants. Depending
  1358. on the set of modules being selected in your kernel configuration,
  1359. many of those exported symbols might never be used.
  1360. This option allows for unused exported symbols to be dropped from
  1361. the build. In turn, this provides the compiler more opportunities
  1362. (especially when using LTO) for optimizing the code and reducing
  1363. binary size. This might have some security advantages as well.
  1364. If unsure say N.
  1365. endif # MODULES
  1366. config INIT_ALL_POSSIBLE
  1367. bool
  1368. help
  1369. Back when each arch used to define their own cpu_online_mask and
  1370. cpu_possible_mask, some of them chose to initialize cpu_possible_mask
  1371. with all 1s, and others with all 0s. When they were centralised,
  1372. it was better to provide this option than to break all the archs
  1373. and have several arch maintainers pursuing me down dark alleys.
  1374. config STOP_MACHINE
  1375. bool
  1376. default y
  1377. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  1378. help
  1379. Need stop_machine() primitive.
  1380. source "block/Kconfig"
  1381. config PREEMPT_NOTIFIERS
  1382. bool
  1383. config PADATA
  1384. depends on SMP
  1385. bool
  1386. source "kernel/Kconfig.locks"