| blob | 7654207961a21cc1757f83dda1efac5cbf2b45eb |
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41 drivers that have been replaced by something else, and/or are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 USER_NS
218 bool "User Namespaces (EXPERIMENTAL)"
219 default n
220 depends on EXPERIMENTAL
221 help
222 Support user namespaces. This allows containers, i.e.
223 vservers, to use user namespaces to provide different
224 user info for different servers. If unsure, say N.
226 config PID_NS
227 bool "PID Namespaces (EXPERIMENTAL)"
228 default n
229 depends on EXPERIMENTAL
230 help
231 Suport process id namespaces. This allows having multiple
232 process with the same pid as long as they are in different
233 pid namespaces. This is a building block of containers.
235 Unless you want to work with an experimental feature
236 say N here.
238 config AUDIT
239 bool "Auditing support"
240 depends on NET
241 help
242 Enable auditing infrastructure that can be used with another
243 kernel subsystem, such as SELinux (which requires this for
244 logging of avc messages output). Does not do system-call
245 auditing without CONFIG_AUDITSYSCALL.
247 config AUDITSYSCALL
248 bool "Enable system-call auditing support"
249 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
250 default y if SECURITY_SELINUX
251 help
252 Enable low-overhead system-call auditing infrastructure that
253 can be used independently or with another kernel subsystem,
254 such as SELinux. To use audit's filesystem watch feature, please
255 ensure that INOTIFY is configured.
257 config AUDIT_TREE
258 def_bool y
259 depends on AUDITSYSCALL && INOTIFY
261 config IKCONFIG
262 tristate "Kernel .config support"
263 ---help---
264 This option enables the complete Linux kernel ".config" file
265 contents to be saved in the kernel. It provides documentation
266 of which kernel options are used in a running kernel or in an
267 on-disk kernel. This information can be extracted from the kernel
268 image file with the script scripts/extract-ikconfig and used as
269 input to rebuild the current kernel or to build another kernel.
270 It can also be extracted from a running kernel by reading
271 /proc/config.gz if enabled (below).
273 config IKCONFIG_PROC
274 bool "Enable access to .config through /proc/config.gz"
275 depends on IKCONFIG && PROC_FS
276 ---help---
277 This option enables access to the kernel configuration file
278 through /proc/config.gz.
280 config LOG_BUF_SHIFT
281 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
282 range 12 21
283 default 17 if S390 || LOCKDEP
284 default 16 if X86_NUMAQ || IA64
285 default 15 if SMP
286 default 14
287 help
288 Select kernel log buffer size as a power of 2.
289 Defaults and Examples:
290 17 => 128 KB for S/390
291 16 => 64 KB for x86 NUMAQ or IA-64
292 15 => 32 KB for SMP
293 14 => 16 KB for uniprocessor
294 13 => 8 KB
295 12 => 4 KB
297 config CGROUPS
298 bool "Control Group support"
299 help
300 This option will let you use process cgroup subsystems
301 such as Cpusets
303 Say N if unsure.
305 config CGROUP_DEBUG
306 bool "Example debug cgroup subsystem"
307 depends on CGROUPS
308 help
309 This option enables a simple cgroup subsystem that
310 exports useful debugging information about the cgroups
311 framework
313 Say N if unsure
315 config CGROUP_NS
316 bool "Namespace cgroup subsystem"
317 depends on CGROUPS
318 help
319 Provides a simple namespace cgroup subsystem to
320 provide hierarchical naming of sets of namespaces,
321 for instance virtual servers and checkpoint/restart
322 jobs.
324 config CPUSETS
325 bool "Cpuset support"
326 depends on SMP && CGROUPS
327 help
328 This option will let you create and manage CPUSETs which
329 allow dynamically partitioning a system into sets of CPUs and
330 Memory Nodes and assigning tasks to run only within those sets.
331 This is primarily useful on large SMP or NUMA systems.
333 Say N if unsure.
335 config FAIR_GROUP_SCHED
336 bool "Fair group CPU scheduler"
337 default y
338 help
339 This feature lets CPU scheduler recognize task groups and control CPU
340 bandwidth allocation to such task groups.
342 choice
343 depends on FAIR_GROUP_SCHED
344 prompt "Basis for grouping tasks"
345 default FAIR_USER_SCHED
347 config FAIR_USER_SCHED
348 bool "user id"
349 help
350 This option will choose userid as the basis for grouping
351 tasks, thus providing equal CPU bandwidth to each user.
353 config FAIR_CGROUP_SCHED
354 bool "Control groups"
355 depends on CGROUPS
356 help
357 This option allows you to create arbitrary task groups
358 using the "cgroup" pseudo filesystem and control
359 the cpu bandwidth allocated to each such task group.
360 Refer to Documentation/cgroups.txt for more information
361 on "cgroup" pseudo filesystem.
363 endchoice
365 config CGROUP_CPUACCT
366 bool "Simple CPU accounting cgroup subsystem"
367 depends on CGROUPS
368 help
369 Provides a simple Resource Controller for monitoring the
370 total CPU consumed by the tasks in a cgroup
372 config RESOURCE_COUNTERS
373 bool "Resource counters"
374 help
375 This option enables controller independent resource accounting
376 infrastructure that works with cgroups
377 depends on CGROUPS
379 config SYSFS_DEPRECATED
380 bool "Create deprecated sysfs files"
381 depends on SYSFS
382 default y
383 help
384 This option creates deprecated symlinks such as the
385 "device"-link, the <subsystem>:<name>-link, and the
386 "bus"-link. It may also add deprecated key in the
387 uevent environment.
388 None of these features or values should be used today, as
389 they export driver core implementation details to userspace
390 or export properties which can't be kept stable across kernel
391 releases.
393 If enabled, this option will also move any device structures
394 that belong to a class, back into the /sys/class hierarchy, in
395 order to support older versions of udev.
397 If you are using a distro that was released in 2006 or later,
398 it should be safe to say N here.
400 config CGROUP_MEM_CONT
401 bool "Memory controller for cgroups"
402 depends on CGROUPS && RESOURCE_COUNTERS
403 help
404 Provides a memory controller that manages both page cache and
405 RSS memory.
407 config PROC_PID_CPUSET
408 bool "Include legacy /proc/<pid>/cpuset file"
409 depends on CPUSETS
410 default y
412 config RELAY
413 bool "Kernel->user space relay support (formerly relayfs)"
414 help
415 This option enables support for relay interface support in
416 certain file systems (such as debugfs).
417 It is designed to provide an efficient mechanism for tools and
418 facilities to relay large amounts of data from kernel space to
419 user space.
421 If unsure, say N.
423 config NAMESPACES
424 bool "Namespaces support" if EMBEDDED
425 default !EMBEDDED
426 help
427 Provides the way to make tasks work with different objects using
428 the same id. For example same IPC id may refer to different objects
429 or same user id or pid may refer to different tasks when used in
430 different namespaces.
432 config BLK_DEV_INITRD
433 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
434 depends on BROKEN || !FRV
435 help
436 The initial RAM filesystem is a ramfs which is loaded by the
437 boot loader (loadlin or lilo) and that is mounted as root
438 before the normal boot procedure. It is typically used to
439 load modules needed to mount the "real" root file system,
440 etc. See <file:Documentation/initrd.txt> for details.
442 If RAM disk support (BLK_DEV_RAM) is also included, this
443 also enables initial RAM disk (initrd) support and adds
444 15 Kbytes (more on some other architectures) to the kernel size.
446 If unsure say Y.
448 if BLK_DEV_INITRD
450 source "usr/Kconfig"
452 endif
454 config CC_OPTIMIZE_FOR_SIZE
455 bool "Optimize for size (Look out for broken compilers!)"
456 default y
457 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
458 help
459 Enabling this option will pass "-Os" instead of "-O2" to gcc
460 resulting in a smaller kernel.
462 WARNING: some versions of gcc may generate incorrect code with this
463 option. If problems are observed, a gcc upgrade may be needed.
465 If unsure, say N.
467 config SYSCTL
468 bool
470 menuconfig EMBEDDED
471 bool "Configure standard kernel features (for small systems)"
472 help
473 This option allows certain base kernel options and settings
474 to be disabled or tweaked. This is for specialized
475 environments which can tolerate a "non-standard" kernel.
476 Only use this if you really know what you are doing.
478 config UID16
479 bool "Enable 16-bit UID system calls" if EMBEDDED
480 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
481 default y
482 help
483 This enables the legacy 16-bit UID syscall wrappers.
485 config SYSCTL_SYSCALL
486 bool "Sysctl syscall support" if EMBEDDED
487 default y
488 select SYSCTL
489 ---help---
490 sys_sysctl uses binary paths that have been found challenging
491 to properly maintain and use. The interface in /proc/sys
492 using paths with ascii names is now the primary path to this
493 information.
495 Almost nothing using the binary sysctl interface so if you are
496 trying to save some space it is probably safe to disable this,
497 making your kernel marginally smaller.
499 If unsure say Y here.
501 config KALLSYMS
502 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
503 default y
504 help
505 Say Y here to let the kernel print out symbolic crash information and
506 symbolic stack backtraces. This increases the size of the kernel
507 somewhat, as all symbols have to be loaded into the kernel image.
509 config KALLSYMS_ALL
510 bool "Include all symbols in kallsyms"
511 depends on DEBUG_KERNEL && KALLSYMS
512 help
513 Normally kallsyms only contains the symbols of functions, for nicer
514 OOPS messages. Some debuggers can use kallsyms for other
515 symbols too: say Y here to include all symbols, if you need them
516 and you don't care about adding 300k to the size of your kernel.
518 Say N.
520 config KALLSYMS_EXTRA_PASS
521 bool "Do an extra kallsyms pass"
522 depends on KALLSYMS
523 help
524 If kallsyms is not working correctly, the build will fail with
525 inconsistent kallsyms data. If that occurs, log a bug report and
526 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
527 Always say N here unless you find a bug in kallsyms, which must be
528 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
529 you wait for kallsyms to be fixed.
532 config HOTPLUG
533 bool "Support for hot-pluggable devices" if EMBEDDED
534 default y
535 help
536 This option is provided for the case where no hotplug or uevent
537 capabilities is wanted by the kernel. You should only consider
538 disabling this option for embedded systems that do not use modules, a
539 dynamic /dev tree, or dynamic device discovery. Just say Y.
541 config PRINTK
542 default y
543 bool "Enable support for printk" if EMBEDDED
544 help
545 This option enables normal printk support. Removing it
546 eliminates most of the message strings from the kernel image
547 and makes the kernel more or less silent. As this makes it
548 very difficult to diagnose system problems, saying N here is
549 strongly discouraged.
551 config BUG
552 bool "BUG() support" if EMBEDDED
553 default y
554 help
555 Disabling this option eliminates support for BUG and WARN, reducing
556 the size of your kernel image and potentially quietly ignoring
557 numerous fatal conditions. You should only consider disabling this
558 option for embedded systems with no facilities for reporting errors.
559 Just say Y.
561 config ELF_CORE
562 default y
563 bool "Enable ELF core dumps" if EMBEDDED
564 help
565 Enable support for generating core dumps. Disabling saves about 4k.
567 config COMPAT_BRK
568 bool "Disable heap randomization"
569 default y
570 help
571 Randomizing heap placement makes heap exploits harder, but it
572 also breaks ancient binaries (including anything libc5 based).
573 This option changes the bootup default to heap randomization
574 disabled, and can be overriden runtime by setting
575 /proc/sys/kernel/randomize_va_space to 2.
577 On non-ancient distros (post-2000 ones) Y is usually a safe choice.
579 config BASE_FULL
580 default y
581 bool "Enable full-sized data structures for core" if EMBEDDED
582 help
583 Disabling this option reduces the size of miscellaneous core
584 kernel data structures. This saves memory on small machines,
585 but may reduce performance.
587 config FUTEX
588 bool "Enable futex support" if EMBEDDED
589 default y
590 select RT_MUTEXES
591 help
592 Disabling this option will cause the kernel to be built without
593 support for "fast userspace mutexes". The resulting kernel may not
594 run glibc-based applications correctly.
596 config ANON_INODES
597 bool
599 config EPOLL
600 bool "Enable eventpoll support" if EMBEDDED
601 default y
602 select ANON_INODES
603 help
604 Disabling this option will cause the kernel to be built without
605 support for epoll family of system calls.
607 config SIGNALFD
608 bool "Enable signalfd() system call" if EMBEDDED
609 select ANON_INODES
610 default y
611 help
612 Enable the signalfd() system call that allows to receive signals
613 on a file descriptor.
615 If unsure, say Y.
617 config TIMERFD
618 bool "Enable timerfd() system call" if EMBEDDED
619 select ANON_INODES
620 default y
621 help
622 Enable the timerfd() system call that allows to receive timer
623 events on a file descriptor.
625 If unsure, say Y.
627 config EVENTFD
628 bool "Enable eventfd() system call" if EMBEDDED
629 select ANON_INODES
630 default y
631 help
632 Enable the eventfd() system call that allows to receive both
633 kernel notification (ie. KAIO) or userspace notifications.
635 If unsure, say Y.
637 config SHMEM
638 bool "Use full shmem filesystem" if EMBEDDED
639 default y
640 depends on MMU
641 help
642 The shmem is an internal filesystem used to manage shared memory.
643 It is backed by swap and manages resource limits. It is also exported
644 to userspace as tmpfs if TMPFS is enabled. Disabling this
645 option replaces shmem and tmpfs with the much simpler ramfs code,
646 which may be appropriate on small systems without swap.
648 config VM_EVENT_COUNTERS
649 default y
650 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
651 help
652 VM event counters are needed for event counts to be shown.
653 This option allows the disabling of the VM event counters
654 on EMBEDDED systems. /proc/vmstat will only show page counts
655 if VM event counters are disabled.
657 config SLUB_DEBUG
658 default y
659 bool "Enable SLUB debugging support" if EMBEDDED
660 depends on SLUB
661 help
662 SLUB has extensive debug support features. Disabling these can
663 result in significant savings in code size. This also disables
664 SLUB sysfs support. /sys/slab will not exist and there will be
665 no support for cache validation etc.
667 choice
668 prompt "Choose SLAB allocator"
669 default SLUB
670 help
671 This option allows to select a slab allocator.
673 config SLAB
674 bool "SLAB"
675 help
676 The regular slab allocator that is established and known to work
677 well in all environments. It organizes cache hot objects in
678 per cpu and per node queues. SLAB is the default choice for
679 a slab allocator.
681 config SLUB
682 bool "SLUB (Unqueued Allocator)"
683 help
684 SLUB is a slab allocator that minimizes cache line usage
685 instead of managing queues of cached objects (SLAB approach).
686 Per cpu caching is realized using slabs of objects instead
687 of queues of objects. SLUB can use memory efficiently
688 and has enhanced diagnostics.
690 config SLOB
691 depends on EMBEDDED
692 bool "SLOB (Simple Allocator)"
693 help
694 SLOB replaces the stock allocator with a drastically simpler
695 allocator. SLOB is generally more space efficient but
696 does not perform as well on large systems.
698 endchoice
700 config PROFILING
701 bool "Profiling support (EXPERIMENTAL)"
702 help
703 Say Y here to enable the extended profiling support mechanisms used
704 by profilers such as OProfile.
706 config MARKERS
707 bool "Activate markers"
708 help
709 Place an empty function call at each marker site. Can be
710 dynamically changed for a probe function.
712 source "arch/Kconfig"
714 config PROC_PAGE_MONITOR
715 default y
716 depends on PROC_FS && MMU
717 bool "Enable /proc page monitoring" if EMBEDDED
718 help
719 Various /proc files exist to monitor process memory utilization:
720 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
721 /proc/kpagecount, and /proc/kpageflags. Disabling these
722 interfaces will reduce the size of the kernel by approximately 4kb.
724 endmenu # General setup
726 config SLABINFO
727 bool
728 depends on PROC_FS
729 depends on SLAB || SLUB
730 default y
732 config RT_MUTEXES
733 boolean
734 select PLIST
736 config TINY_SHMEM
737 default !SHMEM
738 bool
740 config BASE_SMALL
741 int
742 default 0 if BASE_FULL
743 default 1 if !BASE_FULL
745 menuconfig MODULES
746 bool "Enable loadable module support"
747 help
748 Kernel modules are small pieces of compiled code which can
749 be inserted in the running kernel, rather than being
750 permanently built into the kernel. You use the "modprobe"
751 tool to add (and sometimes remove) them. If you say Y here,
752 many parts of the kernel can be built as modules (by
753 answering M instead of Y where indicated): this is most
754 useful for infrequently used options which are not required
755 for booting. For more information, see the man pages for
756 modprobe, lsmod, modinfo, insmod and rmmod.
758 If you say Y here, you will need to run "make
759 modules_install" to put the modules under /lib/modules/
760 where modprobe can find them (you may need to be root to do
761 this).
763 If unsure, say Y.
765 config MODULE_UNLOAD
766 bool "Module unloading"
767 depends on MODULES
768 help
769 Without this option you will not be able to unload any
770 modules (note that some modules may not be unloadable
771 anyway), which makes your kernel slightly smaller and
772 simpler. If unsure, say Y.
774 config MODULE_FORCE_UNLOAD
775 bool "Forced module unloading"
776 depends on MODULE_UNLOAD && EXPERIMENTAL
777 help
778 This option allows you to force a module to unload, even if the
779 kernel believes it is unsafe: the kernel will remove the module
780 without waiting for anyone to stop using it (using the -f option to
781 rmmod). This is mainly for kernel developers and desperate users.
782 If unsure, say N.
784 config MODVERSIONS
785 bool "Module versioning support"
786 depends on MODULES
787 help
788 Usually, you have to use modules compiled with your kernel.
789 Saying Y here makes it sometimes possible to use modules
790 compiled for different kernels, by adding enough information
791 to the modules to (hopefully) spot any changes which would
792 make them incompatible with the kernel you are running. If
793 unsure, say N.
795 config MODULE_SRCVERSION_ALL
796 bool "Source checksum for all modules"
797 depends on MODULES
798 help
799 Modules which contain a MODULE_VERSION get an extra "srcversion"
800 field inserted into their modinfo section, which contains a
801 sum of the source files which made it. This helps maintainers
802 see exactly which source was used to build a module (since
803 others sometimes change the module source without updating
804 the version). With this option, such a "srcversion" field
805 will be created for all modules. If unsure, say N.
807 config KMOD
808 bool "Automatic kernel module loading"
809 depends on MODULES
810 help
811 Normally when you have selected some parts of the kernel to
812 be created as kernel modules, you must load them (using the
813 "modprobe" command) before you can use them. If you say Y
814 here, some parts of the kernel will be able to load modules
815 automatically: when a part of the kernel needs a module, it
816 runs modprobe with the appropriate arguments, thereby
817 loading the module if it is available. If unsure, say Y.
819 config STOP_MACHINE
820 bool
821 default y
822 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
823 help
824 Need stop_machine() primitive.
826 source "block/Kconfig"
828 config PREEMPT_NOTIFIERS
829 bool
831 choice
832 prompt "RCU implementation type:"
833 default CLASSIC_RCU
834 help
835 This allows you to choose either the classic RCU implementation
836 that is designed for best read-side performance on non-realtime
837 systems, or the preemptible RCU implementation for best latency
838 on realtime systems. Note that some kernel preemption modes
839 will restrict your choice.
841 Select the default if you are unsure.
843 config CLASSIC_RCU
844 bool "Classic RCU"
845 help
846 This option selects the classic RCU implementation that is
847 designed for best read-side performance on non-realtime
848 systems.
850 Say Y if you are unsure.
852 config PREEMPT_RCU
853 bool "Preemptible RCU"
854 depends on PREEMPT
855 help
856 This option reduces the latency of the kernel by making certain
857 RCU sections preemptible. Normally RCU code is non-preemptible, if
858 this option is selected then read-only RCU sections become
859 preemptible. This helps latency, but may expose bugs due to
860 now-naive assumptions about each RCU read-side critical section
861 remaining on a given CPU through its execution.
863 Say N if you are unsure.
865 endchoice