| blob | f698a5af500791ae7158457f16c9f00df503cbbb |
1 config ARCH
2 string
3 option env="ARCH"
5 config KERNELVERSION
6 string
7 option env="KERNELVERSION"
9 config DEFCONFIG_LIST
10 string
11 depends on !UML
12 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "arch/$ARCH/defconfig"
18 menu "General setup"
20 config EXPERIMENTAL
21 bool "Prompt for development and/or incomplete code/drivers"
22 ---help---
23 Some of the various things that Linux supports (such as network
24 drivers, file systems, network protocols, etc.) can be in a state
25 of development where the functionality, stability, or the level of
26 testing is not yet high enough for general use. This is usually
27 known as the "alpha-test" phase among developers. If a feature is
28 currently in alpha-test, then the developers usually discourage
29 uninformed widespread use of this feature by the general public to
30 avoid "Why doesn't this work?" type mail messages. However, active
31 testing and use of these systems is welcomed. Just be aware that it
32 may not meet the normal level of reliability or it may fail to work
33 in some special cases. Detailed bug reports from people familiar
34 with the kernel internals are usually welcomed by the developers
35 (before submitting bug reports, please read the documents
36 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
37 <file:Documentation/BUG-HUNTING>, and
38 <file:Documentation/oops-tracing.txt> in the kernel source).
40 This option will also make obsoleted drivers available. These are
41 drivers that have been replaced by something else, and/or are
42 scheduled to be removed in a future kernel release.
44 Unless you intend to help test and develop a feature or driver that
45 falls into this category, or you have a situation that requires
46 using these features, you should probably say N here, which will
47 cause the configurator to present you with fewer choices. If
48 you say Y here, you will be offered the choice of using features or
49 drivers that are currently considered to be in the alpha-test phase.
51 config BROKEN
52 bool
54 config BROKEN_ON_SMP
55 bool
56 depends on BROKEN || !SMP
57 default y
59 config LOCK_KERNEL
60 bool
61 depends on SMP || PREEMPT
62 default y
64 config INIT_ENV_ARG_LIMIT
65 int
66 default 32 if !UML
67 default 128 if UML
68 help
69 Maximum of each of the number of arguments and environment
70 variables passed to init from the kernel command line.
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.
83 config LOCALVERSION_AUTO
84 bool "Automatically append version information to the version string"
85 default y
86 help
87 This will try to automatically determine if the current tree is a
88 release tree by looking for git tags that belong to the current
89 top of tree revision.
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.
96 (The actual string used here is the first eight characters produced
97 by running the command:
99 $ git rev-parse --verify HEAD
101 which is done within the script "scripts/setlocalversion".)
103 config SWAP
104 bool "Support for paging of anonymous memory (swap)"
105 depends on MMU && BLOCK
106 default y
107 help
108 This option allows you to choose whether you want to have support
109 for so called swap devices or swap files in your kernel that are
110 used to provide more virtual memory than the actual RAM present
111 in your computer. If unsure say Y.
113 config SYSVIPC
114 bool "System V IPC"
115 ---help---
116 Inter Process Communication is a suite of library functions and
117 system calls which let processes (running programs) synchronize and
118 exchange information. It is generally considered to be a good thing,
119 and some programs won't run unless you say Y here. In particular, if
120 you want to run the DOS emulator dosemu under Linux (read the
121 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
122 you'll need to say Y here.
124 You can find documentation about IPC with "info ipc" and also in
125 section 6.4 of the Linux Programmer's Guide, available from
126 <http://www.tldp.org/guides.html>.
128 config SYSVIPC_SYSCTL
129 bool
130 depends on SYSVIPC
131 depends on SYSCTL
132 default y
134 config POSIX_MQUEUE
135 bool "POSIX Message Queues"
136 depends on NET && EXPERIMENTAL
137 ---help---
138 POSIX variant of message queues is a part of IPC. In POSIX message
139 queues every message has a priority which decides about succession
140 of receiving it by a process. If you want to compile and run
141 programs written e.g. for Solaris with use of its POSIX message
142 queues (functions mq_*) say Y here.
144 POSIX message queues are visible as a filesystem called 'mqueue'
145 and can be mounted somewhere if you want to do filesystem
146 operations on message queues.
148 If unsure, say Y.
150 config BSD_PROCESS_ACCT
151 bool "BSD Process Accounting"
152 help
153 If you say Y here, a user level program will be able to instruct the
154 kernel (via a special system call) to write process accounting
155 information to a file: whenever a process exits, information about
156 that process will be appended to the file by the kernel. The
157 information includes things such as creation time, owning user,
158 command name, memory usage, controlling terminal etc. (the complete
159 list is in the struct acct in <file:include/linux/acct.h>). It is
160 up to the user level program to do useful things with this
161 information. This is generally a good idea, so say Y.
163 config BSD_PROCESS_ACCT_V3
164 bool "BSD Process Accounting version 3 file format"
165 depends on BSD_PROCESS_ACCT
166 default n
167 help
168 If you say Y here, the process accounting information is written
169 in a new file format that also logs the process IDs of each
170 process and it's parent. Note that this file format is incompatible
171 with previous v0/v1/v2 file formats, so you will need updated tools
172 for processing it. A preliminary version of these tools is available
173 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
175 config TASKSTATS
176 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
177 depends on NET
178 default n
179 help
180 Export selected statistics for tasks/processes through the
181 generic netlink interface. Unlike BSD process accounting, the
182 statistics are available during the lifetime of tasks/processes as
183 responses to commands. Like BSD accounting, they are sent to user
184 space on task exit.
186 Say N if unsure.
188 config TASK_DELAY_ACCT
189 bool "Enable per-task delay accounting (EXPERIMENTAL)"
190 depends on TASKSTATS
191 help
192 Collect information on time spent by a task waiting for system
193 resources like cpu, synchronous block I/O completion and swapping
194 in pages. Such statistics can help in setting a task's priorities
195 relative to other tasks for cpu, io, rss limits etc.
197 Say N if unsure.
199 config TASK_XACCT
200 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
201 depends on TASKSTATS
202 help
203 Collect extended task accounting data and send the data
204 to userland for processing over the taskstats interface.
206 Say N if unsure.
208 config TASK_IO_ACCOUNTING
209 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
210 depends on TASK_XACCT
211 help
212 Collect information on the number of bytes of storage I/O which this
213 task has caused.
215 Say N if unsure.
217 config AUDIT
218 bool "Auditing support"
219 depends on NET
220 help
221 Enable auditing infrastructure that can be used with another
222 kernel subsystem, such as SELinux (which requires this for
223 logging of avc messages output). Does not do system-call
224 auditing without CONFIG_AUDITSYSCALL.
226 config AUDITSYSCALL
227 bool "Enable system-call auditing support"
228 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
229 default y if SECURITY_SELINUX
230 help
231 Enable low-overhead system-call auditing infrastructure that
232 can be used independently or with another kernel subsystem,
233 such as SELinux. To use audit's filesystem watch feature, please
234 ensure that INOTIFY is configured.
236 config AUDIT_TREE
237 def_bool y
238 depends on AUDITSYSCALL && INOTIFY
240 config IKCONFIG
241 tristate "Kernel .config support"
242 ---help---
243 This option enables the complete Linux kernel ".config" file
244 contents to be saved in the kernel. It provides documentation
245 of which kernel options are used in a running kernel or in an
246 on-disk kernel. This information can be extracted from the kernel
247 image file with the script scripts/extract-ikconfig and used as
248 input to rebuild the current kernel or to build another kernel.
249 It can also be extracted from a running kernel by reading
250 /proc/config.gz if enabled (below).
252 config IKCONFIG_PROC
253 bool "Enable access to .config through /proc/config.gz"
254 depends on IKCONFIG && PROC_FS
255 ---help---
256 This option enables access to the kernel configuration file
257 through /proc/config.gz.
259 config LOG_BUF_SHIFT
260 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
261 range 12 21
262 default 17 if S390 || LOCKDEP
263 default 16 if X86_NUMAQ || IA64
264 default 15 if SMP
265 default 14
266 help
267 Select kernel log buffer size as a power of 2.
268 Defaults and Examples:
269 17 => 128 KB for S/390
270 16 => 64 KB for x86 NUMAQ or IA-64
271 15 => 32 KB for SMP
272 14 => 16 KB for uniprocessor
273 13 => 8 KB
274 12 => 4 KB
276 config CGROUPS
277 bool "Control Group support"
278 help
279 This option will let you use process cgroup subsystems
280 such as Cpusets
282 Say N if unsure.
284 config CGROUP_DEBUG
285 bool "Example debug cgroup subsystem"
286 depends on CGROUPS
287 help
288 This option enables a simple cgroup subsystem that
289 exports useful debugging information about the cgroups
290 framework
292 Say N if unsure
294 config CGROUP_NS
295 bool "Namespace cgroup subsystem"
296 depends on CGROUPS
297 help
298 Provides a simple namespace cgroup subsystem to
299 provide hierarchical naming of sets of namespaces,
300 for instance virtual servers and checkpoint/restart
301 jobs.
303 config CPUSETS
304 bool "Cpuset support"
305 depends on SMP && CGROUPS
306 help
307 This option will let you create and manage CPUSETs which
308 allow dynamically partitioning a system into sets of CPUs and
309 Memory Nodes and assigning tasks to run only within those sets.
310 This is primarily useful on large SMP or NUMA systems.
312 Say N if unsure.
314 config GROUP_SCHED
315 bool "Group CPU scheduler"
316 default y
317 help
318 This feature lets CPU scheduler recognize task groups and control CPU
319 bandwidth allocation to such task groups.
321 config FAIR_GROUP_SCHED
322 bool "Group scheduling for SCHED_OTHER"
323 depends on GROUP_SCHED
324 default y
326 config RT_GROUP_SCHED
327 bool "Group scheduling for SCHED_RR/FIFO"
328 depends on EXPERIMENTAL
329 depends on GROUP_SCHED
330 default n
332 choice
333 depends on GROUP_SCHED
334 prompt "Basis for grouping tasks"
335 default USER_SCHED
337 config USER_SCHED
338 bool "user id"
339 help
340 This option will choose userid as the basis for grouping
341 tasks, thus providing equal CPU bandwidth to each user.
343 config CGROUP_SCHED
344 bool "Control groups"
345 depends on CGROUPS
346 help
347 This option allows you to create arbitrary task groups
348 using the "cgroup" pseudo filesystem and control
349 the cpu bandwidth allocated to each such task group.
350 Refer to Documentation/cgroups.txt for more information
351 on "cgroup" pseudo filesystem.
353 endchoice
355 config CGROUP_CPUACCT
356 bool "Simple CPU accounting cgroup subsystem"
357 depends on CGROUPS
358 help
359 Provides a simple Resource Controller for monitoring the
360 total CPU consumed by the tasks in a cgroup
362 config RESOURCE_COUNTERS
363 bool "Resource counters"
364 help
365 This option enables controller independent resource accounting
366 infrastructure that works with cgroups
367 depends on CGROUPS
369 config SYSFS_DEPRECATED
370 bool "Create deprecated sysfs files"
371 depends on SYSFS
372 default y
373 help
374 This option creates deprecated symlinks such as the
375 "device"-link, the <subsystem>:<name>-link, and the
376 "bus"-link. It may also add deprecated key in the
377 uevent environment.
378 None of these features or values should be used today, as
379 they export driver core implementation details to userspace
380 or export properties which can't be kept stable across kernel
381 releases.
383 If enabled, this option will also move any device structures
384 that belong to a class, back into the /sys/class hierarchy, in
385 order to support older versions of udev.
387 If you are using a distro that was released in 2006 or later,
388 it should be safe to say N here.
390 config CGROUP_MEM_CONT
391 bool "Memory controller for cgroups"
392 depends on CGROUPS && RESOURCE_COUNTERS
393 help
394 Provides a memory controller that manages both page cache and
395 RSS memory.
397 Note that setting this option increases fixed memory overhead
398 associated with each page of memory in the system by 4/8 bytes
399 and also increases cache misses because struct page on many 64bit
400 systems will not fit into a single cache line anymore.
402 Only enable when you're ok with these trade offs and really
403 sure you need the memory controller.
405 config PROC_PID_CPUSET
406 bool "Include legacy /proc/<pid>/cpuset file"
407 depends on CPUSETS
408 default y
410 config RELAY
411 bool "Kernel->user space relay support (formerly relayfs)"
412 help
413 This option enables support for relay interface support in
414 certain file systems (such as debugfs).
415 It is designed to provide an efficient mechanism for tools and
416 facilities to relay large amounts of data from kernel space to
417 user space.
419 If unsure, say N.
421 config NAMESPACES
422 bool "Namespaces support" if EMBEDDED
423 default !EMBEDDED
424 help
425 Provides the way to make tasks work with different objects using
426 the same id. For example same IPC id may refer to different objects
427 or same user id or pid may refer to different tasks when used in
428 different namespaces.
430 config UTS_NS
431 bool "UTS namespace"
432 depends on NAMESPACES
433 help
434 In this namespace tasks see different info provided with the
435 uname() system call
437 config IPC_NS
438 bool "IPC namespace"
439 depends on NAMESPACES && SYSVIPC
440 help
441 In this namespace tasks work with IPC ids which correspond to
442 different IPC objects in different namespaces
444 config USER_NS
445 bool "User namespace (EXPERIMENTAL)"
446 depends on NAMESPACES && EXPERIMENTAL
447 help
448 This allows containers, i.e. vservers, to use user namespaces
449 to provide different user info for different servers.
450 If unsure, say N.
452 config PID_NS
453 bool "PID Namespaces (EXPERIMENTAL)"
454 default n
455 depends on NAMESPACES && EXPERIMENTAL
456 help
457 Suport process id namespaces. This allows having multiple
458 process with the same pid as long as they are in different
459 pid namespaces. This is a building block of containers.
461 Unless you want to work with an experimental feature
462 say N here.
464 config BLK_DEV_INITRD
465 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
466 depends on BROKEN || !FRV
467 help
468 The initial RAM filesystem is a ramfs which is loaded by the
469 boot loader (loadlin or lilo) and that is mounted as root
470 before the normal boot procedure. It is typically used to
471 load modules needed to mount the "real" root file system,
472 etc. See <file:Documentation/initrd.txt> for details.
474 If RAM disk support (BLK_DEV_RAM) is also included, this
475 also enables initial RAM disk (initrd) support and adds
476 15 Kbytes (more on some other architectures) to the kernel size.
478 If unsure say Y.
480 if BLK_DEV_INITRD
482 source "usr/Kconfig"
484 endif
486 config CC_OPTIMIZE_FOR_SIZE
487 bool "Optimize for size (Look out for broken compilers!)"
488 default y
489 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
490 help
491 Enabling this option will pass "-Os" instead of "-O2" to gcc
492 resulting in a smaller kernel.
494 WARNING: some versions of gcc may generate incorrect code with this
495 option. If problems are observed, a gcc upgrade may be needed.
497 If unsure, say N.
499 config SYSCTL
500 bool
502 menuconfig EMBEDDED
503 bool "Configure standard kernel features (for small systems)"
504 help
505 This option allows certain base kernel options and settings
506 to be disabled or tweaked. This is for specialized
507 environments which can tolerate a "non-standard" kernel.
508 Only use this if you really know what you are doing.
510 config UID16
511 bool "Enable 16-bit UID system calls" if EMBEDDED
512 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
513 default y
514 help
515 This enables the legacy 16-bit UID syscall wrappers.
517 config SYSCTL_SYSCALL
518 bool "Sysctl syscall support" if EMBEDDED
519 default y
520 select SYSCTL
521 ---help---
522 sys_sysctl uses binary paths that have been found challenging
523 to properly maintain and use. The interface in /proc/sys
524 using paths with ascii names is now the primary path to this
525 information.
527 Almost nothing using the binary sysctl interface so if you are
528 trying to save some space it is probably safe to disable this,
529 making your kernel marginally smaller.
531 If unsure say Y here.
533 config KALLSYMS
534 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
535 default y
536 help
537 Say Y here to let the kernel print out symbolic crash information and
538 symbolic stack backtraces. This increases the size of the kernel
539 somewhat, as all symbols have to be loaded into the kernel image.
541 config KALLSYMS_ALL
542 bool "Include all symbols in kallsyms"
543 depends on DEBUG_KERNEL && KALLSYMS
544 help
545 Normally kallsyms only contains the symbols of functions, for nicer
546 OOPS messages. Some debuggers can use kallsyms for other
547 symbols too: say Y here to include all symbols, if you need them
548 and you don't care about adding 300k to the size of your kernel.
550 Say N.
552 config KALLSYMS_EXTRA_PASS
553 bool "Do an extra kallsyms pass"
554 depends on KALLSYMS
555 help
556 If kallsyms is not working correctly, the build will fail with
557 inconsistent kallsyms data. If that occurs, log a bug report and
558 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
559 Always say N here unless you find a bug in kallsyms, which must be
560 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
561 you wait for kallsyms to be fixed.
564 config HOTPLUG
565 bool "Support for hot-pluggable devices" if EMBEDDED
566 default y
567 help
568 This option is provided for the case where no hotplug or uevent
569 capabilities is wanted by the kernel. You should only consider
570 disabling this option for embedded systems that do not use modules, a
571 dynamic /dev tree, or dynamic device discovery. Just say Y.
573 config PRINTK
574 default y
575 bool "Enable support for printk" if EMBEDDED
576 help
577 This option enables normal printk support. Removing it
578 eliminates most of the message strings from the kernel image
579 and makes the kernel more or less silent. As this makes it
580 very difficult to diagnose system problems, saying N here is
581 strongly discouraged.
583 config BUG
584 bool "BUG() support" if EMBEDDED
585 default y
586 help
587 Disabling this option eliminates support for BUG and WARN, reducing
588 the size of your kernel image and potentially quietly ignoring
589 numerous fatal conditions. You should only consider disabling this
590 option for embedded systems with no facilities for reporting errors.
591 Just say Y.
593 config ELF_CORE
594 default y
595 bool "Enable ELF core dumps" if EMBEDDED
596 help
597 Enable support for generating core dumps. Disabling saves about 4k.
599 config COMPAT_BRK
600 bool "Disable heap randomization"
601 default y
602 help
603 Randomizing heap placement makes heap exploits harder, but it
604 also breaks ancient binaries (including anything libc5 based).
605 This option changes the bootup default to heap randomization
606 disabled, and can be overriden runtime by setting
607 /proc/sys/kernel/randomize_va_space to 2.
609 On non-ancient distros (post-2000 ones) N is usually a safe choice.
611 config BASE_FULL
612 default y
613 bool "Enable full-sized data structures for core" if EMBEDDED
614 help
615 Disabling this option reduces the size of miscellaneous core
616 kernel data structures. This saves memory on small machines,
617 but may reduce performance.
619 config FUTEX
620 bool "Enable futex support" if EMBEDDED
621 default y
622 select RT_MUTEXES
623 help
624 Disabling this option will cause the kernel to be built without
625 support for "fast userspace mutexes". The resulting kernel may not
626 run glibc-based applications correctly.
628 config ANON_INODES
629 bool
631 config EPOLL
632 bool "Enable eventpoll support" if EMBEDDED
633 default y
634 select ANON_INODES
635 help
636 Disabling this option will cause the kernel to be built without
637 support for epoll family of system calls.
639 config SIGNALFD
640 bool "Enable signalfd() system call" if EMBEDDED
641 select ANON_INODES
642 default y
643 help
644 Enable the signalfd() system call that allows to receive signals
645 on a file descriptor.
647 If unsure, say Y.
649 config TIMERFD
650 bool "Enable timerfd() system call" if EMBEDDED
651 select ANON_INODES
652 default y
653 help
654 Enable the timerfd() system call that allows to receive timer
655 events on a file descriptor.
657 If unsure, say Y.
659 config EVENTFD
660 bool "Enable eventfd() system call" if EMBEDDED
661 select ANON_INODES
662 default y
663 help
664 Enable the eventfd() system call that allows to receive both
665 kernel notification (ie. KAIO) or userspace notifications.
667 If unsure, say Y.
669 config SHMEM
670 bool "Use full shmem filesystem" if EMBEDDED
671 default y
672 depends on MMU
673 help
674 The shmem is an internal filesystem used to manage shared memory.
675 It is backed by swap and manages resource limits. It is also exported
676 to userspace as tmpfs if TMPFS is enabled. Disabling this
677 option replaces shmem and tmpfs with the much simpler ramfs code,
678 which may be appropriate on small systems without swap.
680 config VM_EVENT_COUNTERS
681 default y
682 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
683 help
684 VM event counters are needed for event counts to be shown.
685 This option allows the disabling of the VM event counters
686 on EMBEDDED systems. /proc/vmstat will only show page counts
687 if VM event counters are disabled.
689 config SLUB_DEBUG
690 default y
691 bool "Enable SLUB debugging support" if EMBEDDED
692 depends on SLUB
693 help
694 SLUB has extensive debug support features. Disabling these can
695 result in significant savings in code size. This also disables
696 SLUB sysfs support. /sys/slab will not exist and there will be
697 no support for cache validation etc.
699 choice
700 prompt "Choose SLAB allocator"
701 default SLUB
702 help
703 This option allows to select a slab allocator.
705 config SLAB
706 bool "SLAB"
707 help
708 The regular slab allocator that is established and known to work
709 well in all environments. It organizes cache hot objects in
710 per cpu and per node queues. SLAB is the default choice for
711 a slab allocator.
713 config SLUB
714 bool "SLUB (Unqueued Allocator)"
715 help
716 SLUB is a slab allocator that minimizes cache line usage
717 instead of managing queues of cached objects (SLAB approach).
718 Per cpu caching is realized using slabs of objects instead
719 of queues of objects. SLUB can use memory efficiently
720 and has enhanced diagnostics.
722 config SLOB
723 depends on EMBEDDED
724 bool "SLOB (Simple Allocator)"
725 help
726 SLOB replaces the stock allocator with a drastically simpler
727 allocator. SLOB is generally more space efficient but
728 does not perform as well on large systems.
730 endchoice
732 config PROFILING
733 bool "Profiling support (EXPERIMENTAL)"
734 help
735 Say Y here to enable the extended profiling support mechanisms used
736 by profilers such as OProfile.
738 config MARKERS
739 bool "Activate markers"
740 help
741 Place an empty function call at each marker site. Can be
742 dynamically changed for a probe function.
744 source "arch/Kconfig"
746 config PROC_PAGE_MONITOR
747 default y
748 depends on PROC_FS && MMU
749 bool "Enable /proc page monitoring" if EMBEDDED
750 help
751 Various /proc files exist to monitor process memory utilization:
752 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
753 /proc/kpagecount, and /proc/kpageflags. Disabling these
754 interfaces will reduce the size of the kernel by approximately 4kb.
756 endmenu # General setup
758 config SLABINFO
759 bool
760 depends on PROC_FS
761 depends on SLAB || SLUB
762 default y
764 config RT_MUTEXES
765 boolean
766 select PLIST
768 config TINY_SHMEM
769 default !SHMEM
770 bool
772 config BASE_SMALL
773 int
774 default 0 if BASE_FULL
775 default 1 if !BASE_FULL
777 menuconfig MODULES
778 bool "Enable loadable module support"
779 help
780 Kernel modules are small pieces of compiled code which can
781 be inserted in the running kernel, rather than being
782 permanently built into the kernel. You use the "modprobe"
783 tool to add (and sometimes remove) them. If you say Y here,
784 many parts of the kernel can be built as modules (by
785 answering M instead of Y where indicated): this is most
786 useful for infrequently used options which are not required
787 for booting. For more information, see the man pages for
788 modprobe, lsmod, modinfo, insmod and rmmod.
790 If you say Y here, you will need to run "make
791 modules_install" to put the modules under /lib/modules/
792 where modprobe can find them (you may need to be root to do
793 this).
795 If unsure, say Y.
797 config MODULE_UNLOAD
798 bool "Module unloading"
799 depends on MODULES
800 help
801 Without this option you will not be able to unload any
802 modules (note that some modules may not be unloadable
803 anyway), which makes your kernel slightly smaller and
804 simpler. If unsure, say Y.
806 config MODULE_FORCE_UNLOAD
807 bool "Forced module unloading"
808 depends on MODULE_UNLOAD && EXPERIMENTAL
809 help
810 This option allows you to force a module to unload, even if the
811 kernel believes it is unsafe: the kernel will remove the module
812 without waiting for anyone to stop using it (using the -f option to
813 rmmod). This is mainly for kernel developers and desperate users.
814 If unsure, say N.
816 config MODVERSIONS
817 bool "Module versioning support"
818 depends on MODULES
819 help
820 Usually, you have to use modules compiled with your kernel.
821 Saying Y here makes it sometimes possible to use modules
822 compiled for different kernels, by adding enough information
823 to the modules to (hopefully) spot any changes which would
824 make them incompatible with the kernel you are running. If
825 unsure, say N.
827 config MODULE_SRCVERSION_ALL
828 bool "Source checksum for all modules"
829 depends on MODULES
830 help
831 Modules which contain a MODULE_VERSION get an extra "srcversion"
832 field inserted into their modinfo section, which contains a
833 sum of the source files which made it. This helps maintainers
834 see exactly which source was used to build a module (since
835 others sometimes change the module source without updating
836 the version). With this option, such a "srcversion" field
837 will be created for all modules. If unsure, say N.
839 config KMOD
840 bool "Automatic kernel module loading"
841 depends on MODULES
842 help
843 Normally when you have selected some parts of the kernel to
844 be created as kernel modules, you must load them (using the
845 "modprobe" command) before you can use them. If you say Y
846 here, some parts of the kernel will be able to load modules
847 automatically: when a part of the kernel needs a module, it
848 runs modprobe with the appropriate arguments, thereby
849 loading the module if it is available. If unsure, say Y.
851 config STOP_MACHINE
852 bool
853 default y
854 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
855 help
856 Need stop_machine() primitive.
858 source "block/Kconfig"
860 config PREEMPT_NOTIFIERS
861 bool
863 choice
864 prompt "RCU implementation type:"
865 default CLASSIC_RCU
866 help
867 This allows you to choose either the classic RCU implementation
868 that is designed for best read-side performance on non-realtime
869 systems, or the preemptible RCU implementation for best latency
870 on realtime systems. Note that some kernel preemption modes
871 will restrict your choice.
873 Select the default if you are unsure.
875 config CLASSIC_RCU
876 bool "Classic RCU"
877 help
878 This option selects the classic RCU implementation that is
879 designed for best read-side performance on non-realtime
880 systems.
882 Say Y if you are unsure.
884 config PREEMPT_RCU
885 bool "Preemptible RCU"
886 depends on PREEMPT
887 help
888 This option reduces the latency of the kernel by making certain
889 RCU sections preemptible. Normally RCU code is non-preemptible, if
890 this option is selected then read-only RCU sections become
891 preemptible. This helps latency, but may expose bugs due to
892 now-naive assumptions about each RCU read-side critical section
893 remaining on a given CPU through its execution.
895 Say N if you are unsure.
897 endchoice