Kconfig 23 KB

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  1. config DEFCONFIG_LIST
  2. string
  3. depends on !UML
  4. option defconfig_list
  5. default "/lib/modules/$UNAME_RELEASE/.config"
  6. default "/etc/kernel-config"
  7. default "/boot/config-$UNAME_RELEASE"
  8. default "arch/$ARCH/defconfig"
  9. menu "General setup"
  10. config EXPERIMENTAL
  11. bool "Prompt for development and/or incomplete code/drivers"
  12. ---help---
  13. Some of the various things that Linux supports (such as network
  14. drivers, file systems, network protocols, etc.) can be in a state
  15. of development where the functionality, stability, or the level of
  16. testing is not yet high enough for general use. This is usually
  17. known as the "alpha-test" phase among developers. If a feature is
  18. currently in alpha-test, then the developers usually discourage
  19. uninformed widespread use of this feature by the general public to
  20. avoid "Why doesn't this work?" type mail messages. However, active
  21. testing and use of these systems is welcomed. Just be aware that it
  22. may not meet the normal level of reliability or it may fail to work
  23. in some special cases. Detailed bug reports from people familiar
  24. with the kernel internals are usually welcomed by the developers
  25. (before submitting bug reports, please read the documents
  26. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  27. <file:Documentation/BUG-HUNTING>, and
  28. <file:Documentation/oops-tracing.txt> in the kernel source).
  29. This option will also make obsoleted drivers available. These are
  30. drivers that have been replaced by something else, and/or are
  31. scheduled to be removed in a future kernel release.
  32. Unless you intend to help test and develop a feature or driver that
  33. falls into this category, or you have a situation that requires
  34. using these features, you should probably say N here, which will
  35. cause the configurator to present you with fewer choices. If
  36. you say Y here, you will be offered the choice of using features or
  37. drivers that are currently considered to be in the alpha-test phase.
  38. config BROKEN
  39. bool
  40. config BROKEN_ON_SMP
  41. bool
  42. depends on BROKEN || !SMP
  43. default y
  44. config LOCK_KERNEL
  45. bool
  46. depends on SMP || PREEMPT
  47. default y
  48. config INIT_ENV_ARG_LIMIT
  49. int
  50. default 32 if !UML
  51. default 128 if UML
  52. help
  53. Maximum of each of the number of arguments and environment
  54. variables passed to init from the kernel command line.
  55. config LOCALVERSION
  56. string "Local version - append to kernel release"
  57. help
  58. Append an extra string to the end of your kernel version.
  59. This will show up when you type uname, for example.
  60. The string you set here will be appended after the contents of
  61. any files with a filename matching localversion* in your
  62. object and source tree, in that order. Your total string can
  63. be a maximum of 64 characters.
  64. config LOCALVERSION_AUTO
  65. bool "Automatically append version information to the version string"
  66. default y
  67. help
  68. This will try to automatically determine if the current tree is a
  69. release tree by looking for git tags that belong to the current
  70. top of tree revision.
  71. A string of the format -gxxxxxxxx will be added to the localversion
  72. if a git-based tree is found. The string generated by this will be
  73. appended after any matching localversion* files, and after the value
  74. set in CONFIG_LOCALVERSION.
  75. (The actual string used here is the first eight characters produced
  76. by running the command:
  77. $ git rev-parse --verify HEAD
  78. which is done within the script "scripts/setlocalversion".)
  79. config SWAP
  80. bool "Support for paging of anonymous memory (swap)"
  81. depends on MMU && BLOCK
  82. default y
  83. help
  84. This option allows you to choose whether you want to have support
  85. for so called swap devices or swap files in your kernel that are
  86. used to provide more virtual memory than the actual RAM present
  87. in your computer. If unsure say Y.
  88. config SYSVIPC
  89. bool "System V IPC"
  90. ---help---
  91. Inter Process Communication is a suite of library functions and
  92. system calls which let processes (running programs) synchronize and
  93. exchange information. It is generally considered to be a good thing,
  94. and some programs won't run unless you say Y here. In particular, if
  95. you want to run the DOS emulator dosemu under Linux (read the
  96. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  97. you'll need to say Y here.
  98. You can find documentation about IPC with "info ipc" and also in
  99. section 6.4 of the Linux Programmer's Guide, available from
  100. <http://www.tldp.org/guides.html>.
  101. config SYSVIPC_SYSCTL
  102. bool
  103. depends on SYSVIPC
  104. depends on SYSCTL
  105. default y
  106. config POSIX_MQUEUE
  107. bool "POSIX Message Queues"
  108. depends on NET && EXPERIMENTAL
  109. ---help---
  110. POSIX variant of message queues is a part of IPC. In POSIX message
  111. queues every message has a priority which decides about succession
  112. of receiving it by a process. If you want to compile and run
  113. programs written e.g. for Solaris with use of its POSIX message
  114. queues (functions mq_*) say Y here.
  115. POSIX message queues are visible as a filesystem called 'mqueue'
  116. and can be mounted somewhere if you want to do filesystem
  117. operations on message queues.
  118. If unsure, say Y.
  119. config BSD_PROCESS_ACCT
  120. bool "BSD Process Accounting"
  121. help
  122. If you say Y here, a user level program will be able to instruct the
  123. kernel (via a special system call) to write process accounting
  124. information to a file: whenever a process exits, information about
  125. that process will be appended to the file by the kernel. The
  126. information includes things such as creation time, owning user,
  127. command name, memory usage, controlling terminal etc. (the complete
  128. list is in the struct acct in <file:include/linux/acct.h>). It is
  129. up to the user level program to do useful things with this
  130. information. This is generally a good idea, so say Y.
  131. config BSD_PROCESS_ACCT_V3
  132. bool "BSD Process Accounting version 3 file format"
  133. depends on BSD_PROCESS_ACCT
  134. default n
  135. help
  136. If you say Y here, the process accounting information is written
  137. in a new file format that also logs the process IDs of each
  138. process and it's parent. Note that this file format is incompatible
  139. with previous v0/v1/v2 file formats, so you will need updated tools
  140. for processing it. A preliminary version of these tools is available
  141. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  142. config TASKSTATS
  143. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  144. depends on NET
  145. default n
  146. help
  147. Export selected statistics for tasks/processes through the
  148. generic netlink interface. Unlike BSD process accounting, the
  149. statistics are available during the lifetime of tasks/processes as
  150. responses to commands. Like BSD accounting, they are sent to user
  151. space on task exit.
  152. Say N if unsure.
  153. config TASK_DELAY_ACCT
  154. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  155. depends on TASKSTATS
  156. help
  157. Collect information on time spent by a task waiting for system
  158. resources like cpu, synchronous block I/O completion and swapping
  159. in pages. Such statistics can help in setting a task's priorities
  160. relative to other tasks for cpu, io, rss limits etc.
  161. Say N if unsure.
  162. config TASK_XACCT
  163. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  164. depends on TASKSTATS
  165. help
  166. Collect extended task accounting data and send the data
  167. to userland for processing over the taskstats interface.
  168. Say N if unsure.
  169. config TASK_IO_ACCOUNTING
  170. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  171. depends on TASK_XACCT
  172. help
  173. Collect information on the number of bytes of storage I/O which this
  174. task has caused.
  175. Say N if unsure.
  176. config USER_NS
  177. bool "User Namespaces (EXPERIMENTAL)"
  178. default n
  179. depends on EXPERIMENTAL
  180. help
  181. Support user namespaces. This allows containers, i.e.
  182. vservers, to use user namespaces to provide different
  183. user info for different servers. If unsure, say N.
  184. config AUDIT
  185. bool "Auditing support"
  186. depends on NET
  187. help
  188. Enable auditing infrastructure that can be used with another
  189. kernel subsystem, such as SELinux (which requires this for
  190. logging of avc messages output). Does not do system-call
  191. auditing without CONFIG_AUDITSYSCALL.
  192. config AUDITSYSCALL
  193. bool "Enable system-call auditing support"
  194. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  195. default y if SECURITY_SELINUX
  196. help
  197. Enable low-overhead system-call auditing infrastructure that
  198. can be used independently or with another kernel subsystem,
  199. such as SELinux. To use audit's filesystem watch feature, please
  200. ensure that INOTIFY is configured.
  201. config IKCONFIG
  202. tristate "Kernel .config support"
  203. ---help---
  204. This option enables the complete Linux kernel ".config" file
  205. contents to be saved in the kernel. It provides documentation
  206. of which kernel options are used in a running kernel or in an
  207. on-disk kernel. This information can be extracted from the kernel
  208. image file with the script scripts/extract-ikconfig and used as
  209. input to rebuild the current kernel or to build another kernel.
  210. It can also be extracted from a running kernel by reading
  211. /proc/config.gz if enabled (below).
  212. config IKCONFIG_PROC
  213. bool "Enable access to .config through /proc/config.gz"
  214. depends on IKCONFIG && PROC_FS
  215. ---help---
  216. This option enables access to the kernel configuration file
  217. through /proc/config.gz.
  218. config LOG_BUF_SHIFT
  219. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  220. range 12 21
  221. default 17 if S390 || LOCKDEP
  222. default 16 if X86_NUMAQ || IA64
  223. default 15 if SMP
  224. default 14
  225. help
  226. Select kernel log buffer size as a power of 2.
  227. Defaults and Examples:
  228. 17 => 128 KB for S/390
  229. 16 => 64 KB for x86 NUMAQ or IA-64
  230. 15 => 32 KB for SMP
  231. 14 => 16 KB for uniprocessor
  232. 13 => 8 KB
  233. 12 => 4 KB
  234. config CGROUPS
  235. bool "Control Group support"
  236. help
  237. This option will let you use process cgroup subsystems
  238. such as Cpusets
  239. Say N if unsure.
  240. config CPUSETS
  241. bool "Cpuset support"
  242. depends on SMP
  243. help
  244. This option will let you create and manage CPUSETs which
  245. allow dynamically partitioning a system into sets of CPUs and
  246. Memory Nodes and assigning tasks to run only within those sets.
  247. This is primarily useful on large SMP or NUMA systems.
  248. Say N if unsure.
  249. config FAIR_GROUP_SCHED
  250. bool "Fair group CPU scheduler"
  251. default y
  252. depends on EXPERIMENTAL
  253. help
  254. This feature lets CPU scheduler recognize task groups and control CPU
  255. bandwidth allocation to such task groups.
  256. choice
  257. depends on FAIR_GROUP_SCHED
  258. prompt "Basis for grouping tasks"
  259. default FAIR_USER_SCHED
  260. config FAIR_USER_SCHED
  261. bool "user id"
  262. help
  263. This option will choose userid as the basis for grouping
  264. tasks, thus providing equal CPU bandwidth to each user.
  265. endchoice
  266. config SYSFS_DEPRECATED
  267. bool "Create deprecated sysfs files"
  268. default y
  269. help
  270. This option creates deprecated symlinks such as the
  271. "device"-link, the <subsystem>:<name>-link, and the
  272. "bus"-link. It may also add deprecated key in the
  273. uevent environment.
  274. None of these features or values should be used today, as
  275. they export driver core implementation details to userspace
  276. or export properties which can't be kept stable across kernel
  277. releases.
  278. If enabled, this option will also move any device structures
  279. that belong to a class, back into the /sys/class hierarchy, in
  280. order to support older versions of udev.
  281. If you are using a distro that was released in 2006 or later,
  282. it should be safe to say N here.
  283. config RELAY
  284. bool "Kernel->user space relay support (formerly relayfs)"
  285. help
  286. This option enables support for relay interface support in
  287. certain file systems (such as debugfs).
  288. It is designed to provide an efficient mechanism for tools and
  289. facilities to relay large amounts of data from kernel space to
  290. user space.
  291. If unsure, say N.
  292. config BLK_DEV_INITRD
  293. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  294. depends on BROKEN || !FRV
  295. help
  296. The initial RAM filesystem is a ramfs which is loaded by the
  297. boot loader (loadlin or lilo) and that is mounted as root
  298. before the normal boot procedure. It is typically used to
  299. load modules needed to mount the "real" root file system,
  300. etc. See <file:Documentation/initrd.txt> for details.
  301. If RAM disk support (BLK_DEV_RAM) is also included, this
  302. also enables initial RAM disk (initrd) support and adds
  303. 15 Kbytes (more on some other architectures) to the kernel size.
  304. If unsure say Y.
  305. if BLK_DEV_INITRD
  306. source "usr/Kconfig"
  307. endif
  308. config CC_OPTIMIZE_FOR_SIZE
  309. bool "Optimize for size (Look out for broken compilers!)"
  310. default y
  311. depends on ARM || H8300 || SUPERH || EXPERIMENTAL
  312. help
  313. Enabling this option will pass "-Os" instead of "-O2" to gcc
  314. resulting in a smaller kernel.
  315. WARNING: some versions of gcc may generate incorrect code with this
  316. option. If problems are observed, a gcc upgrade may be needed.
  317. If unsure, say N.
  318. config SYSCTL
  319. bool
  320. menuconfig EMBEDDED
  321. bool "Configure standard kernel features (for small systems)"
  322. help
  323. This option allows certain base kernel options and settings
  324. to be disabled or tweaked. This is for specialized
  325. environments which can tolerate a "non-standard" kernel.
  326. Only use this if you really know what you are doing.
  327. config UID16
  328. bool "Enable 16-bit UID system calls" if EMBEDDED
  329. depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  330. default y
  331. help
  332. This enables the legacy 16-bit UID syscall wrappers.
  333. config SYSCTL_SYSCALL
  334. bool "Sysctl syscall support" if EMBEDDED
  335. default y
  336. select SYSCTL
  337. ---help---
  338. sys_sysctl uses binary paths that have been found challenging
  339. to properly maintain and use. The interface in /proc/sys
  340. using paths with ascii names is now the primary path to this
  341. information.
  342. Almost nothing using the binary sysctl interface so if you are
  343. trying to save some space it is probably safe to disable this,
  344. making your kernel marginally smaller.
  345. If unsure say Y here.
  346. config KALLSYMS
  347. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  348. default y
  349. help
  350. Say Y here to let the kernel print out symbolic crash information and
  351. symbolic stack backtraces. This increases the size of the kernel
  352. somewhat, as all symbols have to be loaded into the kernel image.
  353. config KALLSYMS_ALL
  354. bool "Include all symbols in kallsyms"
  355. depends on DEBUG_KERNEL && KALLSYMS
  356. help
  357. Normally kallsyms only contains the symbols of functions, for nicer
  358. OOPS messages. Some debuggers can use kallsyms for other
  359. symbols too: say Y here to include all symbols, if you need them
  360. and you don't care about adding 300k to the size of your kernel.
  361. Say N.
  362. config KALLSYMS_EXTRA_PASS
  363. bool "Do an extra kallsyms pass"
  364. depends on KALLSYMS
  365. help
  366. If kallsyms is not working correctly, the build will fail with
  367. inconsistent kallsyms data. If that occurs, log a bug report and
  368. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  369. Always say N here unless you find a bug in kallsyms, which must be
  370. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  371. you wait for kallsyms to be fixed.
  372. config HOTPLUG
  373. bool "Support for hot-pluggable devices" if EMBEDDED
  374. default y
  375. help
  376. This option is provided for the case where no hotplug or uevent
  377. capabilities is wanted by the kernel. You should only consider
  378. disabling this option for embedded systems that do not use modules, a
  379. dynamic /dev tree, or dynamic device discovery. Just say Y.
  380. config PRINTK
  381. default y
  382. bool "Enable support for printk" if EMBEDDED
  383. help
  384. This option enables normal printk support. Removing it
  385. eliminates most of the message strings from the kernel image
  386. and makes the kernel more or less silent. As this makes it
  387. very difficult to diagnose system problems, saying N here is
  388. strongly discouraged.
  389. config BUG
  390. bool "BUG() support" if EMBEDDED
  391. default y
  392. help
  393. Disabling this option eliminates support for BUG and WARN, reducing
  394. the size of your kernel image and potentially quietly ignoring
  395. numerous fatal conditions. You should only consider disabling this
  396. option for embedded systems with no facilities for reporting errors.
  397. Just say Y.
  398. config ELF_CORE
  399. default y
  400. bool "Enable ELF core dumps" if EMBEDDED
  401. help
  402. Enable support for generating core dumps. Disabling saves about 4k.
  403. config BASE_FULL
  404. default y
  405. bool "Enable full-sized data structures for core" if EMBEDDED
  406. help
  407. Disabling this option reduces the size of miscellaneous core
  408. kernel data structures. This saves memory on small machines,
  409. but may reduce performance.
  410. config FUTEX
  411. bool "Enable futex support" if EMBEDDED
  412. default y
  413. select RT_MUTEXES
  414. help
  415. Disabling this option will cause the kernel to be built without
  416. support for "fast userspace mutexes". The resulting kernel may not
  417. run glibc-based applications correctly.
  418. config ANON_INODES
  419. bool
  420. config EPOLL
  421. bool "Enable eventpoll support" if EMBEDDED
  422. default y
  423. select ANON_INODES
  424. help
  425. Disabling this option will cause the kernel to be built without
  426. support for epoll family of system calls.
  427. config SIGNALFD
  428. bool "Enable signalfd() system call" if EMBEDDED
  429. select ANON_INODES
  430. default y
  431. help
  432. Enable the signalfd() system call that allows to receive signals
  433. on a file descriptor.
  434. If unsure, say Y.
  435. config TIMERFD
  436. bool "Enable timerfd() system call" if EMBEDDED
  437. select ANON_INODES
  438. depends on BROKEN
  439. default y
  440. help
  441. Enable the timerfd() system call that allows to receive timer
  442. events on a file descriptor.
  443. If unsure, say Y.
  444. config EVENTFD
  445. bool "Enable eventfd() system call" if EMBEDDED
  446. select ANON_INODES
  447. default y
  448. help
  449. Enable the eventfd() system call that allows to receive both
  450. kernel notification (ie. KAIO) or userspace notifications.
  451. If unsure, say Y.
  452. config SHMEM
  453. bool "Use full shmem filesystem" if EMBEDDED
  454. default y
  455. depends on MMU
  456. help
  457. The shmem is an internal filesystem used to manage shared memory.
  458. It is backed by swap and manages resource limits. It is also exported
  459. to userspace as tmpfs if TMPFS is enabled. Disabling this
  460. option replaces shmem and tmpfs with the much simpler ramfs code,
  461. which may be appropriate on small systems without swap.
  462. config VM_EVENT_COUNTERS
  463. default y
  464. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  465. help
  466. VM event counters are needed for event counts to be shown.
  467. This option allows the disabling of the VM event counters
  468. on EMBEDDED systems. /proc/vmstat will only show page counts
  469. if VM event counters are disabled.
  470. config SLUB_DEBUG
  471. default y
  472. bool "Enable SLUB debugging support" if EMBEDDED
  473. depends on SLUB
  474. help
  475. SLUB has extensive debug support features. Disabling these can
  476. result in significant savings in code size. This also disables
  477. SLUB sysfs support. /sys/slab will not exist and there will be
  478. no support for cache validation etc.
  479. choice
  480. prompt "Choose SLAB allocator"
  481. default SLUB
  482. help
  483. This option allows to select a slab allocator.
  484. config SLAB
  485. bool "SLAB"
  486. help
  487. The regular slab allocator that is established and known to work
  488. well in all environments. It organizes cache hot objects in
  489. per cpu and per node queues. SLAB is the default choice for
  490. a slab allocator.
  491. config SLUB
  492. bool "SLUB (Unqueued Allocator)"
  493. help
  494. SLUB is a slab allocator that minimizes cache line usage
  495. instead of managing queues of cached objects (SLAB approach).
  496. Per cpu caching is realized using slabs of objects instead
  497. of queues of objects. SLUB can use memory efficiently
  498. and has enhanced diagnostics.
  499. config SLOB
  500. depends on EMBEDDED
  501. bool "SLOB (Simple Allocator)"
  502. help
  503. SLOB replaces the SLAB allocator with a drastically simpler
  504. allocator. SLOB is more space efficient than SLAB but does not
  505. scale well (single lock for all operations) and is also highly
  506. susceptible to fragmentation. SLUB can accomplish a higher object
  507. density. It is usually better to use SLUB instead of SLOB.
  508. endchoice
  509. endmenu # General setup
  510. config RT_MUTEXES
  511. boolean
  512. select PLIST
  513. config TINY_SHMEM
  514. default !SHMEM
  515. bool
  516. config BASE_SMALL
  517. int
  518. default 0 if BASE_FULL
  519. default 1 if !BASE_FULL
  520. menuconfig MODULES
  521. bool "Enable loadable module support"
  522. help
  523. Kernel modules are small pieces of compiled code which can
  524. be inserted in the running kernel, rather than being
  525. permanently built into the kernel. You use the "modprobe"
  526. tool to add (and sometimes remove) them. If you say Y here,
  527. many parts of the kernel can be built as modules (by
  528. answering M instead of Y where indicated): this is most
  529. useful for infrequently used options which are not required
  530. for booting. For more information, see the man pages for
  531. modprobe, lsmod, modinfo, insmod and rmmod.
  532. If you say Y here, you will need to run "make
  533. modules_install" to put the modules under /lib/modules/
  534. where modprobe can find them (you may need to be root to do
  535. this).
  536. If unsure, say Y.
  537. config MODULE_UNLOAD
  538. bool "Module unloading"
  539. depends on MODULES
  540. help
  541. Without this option you will not be able to unload any
  542. modules (note that some modules may not be unloadable
  543. anyway), which makes your kernel slightly smaller and
  544. simpler. If unsure, say Y.
  545. config MODULE_FORCE_UNLOAD
  546. bool "Forced module unloading"
  547. depends on MODULE_UNLOAD && EXPERIMENTAL
  548. help
  549. This option allows you to force a module to unload, even if the
  550. kernel believes it is unsafe: the kernel will remove the module
  551. without waiting for anyone to stop using it (using the -f option to
  552. rmmod). This is mainly for kernel developers and desperate users.
  553. If unsure, say N.
  554. config MODVERSIONS
  555. bool "Module versioning support"
  556. depends on MODULES
  557. help
  558. Usually, you have to use modules compiled with your kernel.
  559. Saying Y here makes it sometimes possible to use modules
  560. compiled for different kernels, by adding enough information
  561. to the modules to (hopefully) spot any changes which would
  562. make them incompatible with the kernel you are running. If
  563. unsure, say N.
  564. config MODULE_SRCVERSION_ALL
  565. bool "Source checksum for all modules"
  566. depends on MODULES
  567. help
  568. Modules which contain a MODULE_VERSION get an extra "srcversion"
  569. field inserted into their modinfo section, which contains a
  570. sum of the source files which made it. This helps maintainers
  571. see exactly which source was used to build a module (since
  572. others sometimes change the module source without updating
  573. the version). With this option, such a "srcversion" field
  574. will be created for all modules. If unsure, say N.
  575. config KMOD
  576. bool "Automatic kernel module loading"
  577. depends on MODULES
  578. help
  579. Normally when you have selected some parts of the kernel to
  580. be created as kernel modules, you must load them (using the
  581. "modprobe" command) before you can use them. If you say Y
  582. here, some parts of the kernel will be able to load modules
  583. automatically: when a part of the kernel needs a module, it
  584. runs modprobe with the appropriate arguments, thereby
  585. loading the module if it is available. If unsure, say Y.
  586. config STOP_MACHINE
  587. bool
  588. default y
  589. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  590. help
  591. Need stop_machine() primitive.
  592. source "block/Kconfig"
  593. config PREEMPT_NOTIFIERS
  594. bool