| blob | c5b354b1409e13e80d32e366b5a9844d9481e0d6 |
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"
10 menu "General setup"
12 config EXPERIMENTAL
13 bool "Prompt for development and/or incomplete code/drivers"
14 ---help---
15 Some of the various things that Linux supports (such as network
16 drivers, file systems, network protocols, etc.) can be in a state
17 of development where the functionality, stability, or the level of
18 testing is not yet high enough for general use. This is usually
19 known as the "alpha-test" phase among developers. If a feature is
20 currently in alpha-test, then the developers usually discourage
21 uninformed widespread use of this feature by the general public to
22 avoid "Why doesn't this work?" type mail messages. However, active
23 testing and use of these systems is welcomed. Just be aware that it
24 may not meet the normal level of reliability or it may fail to work
25 in some special cases. Detailed bug reports from people familiar
26 with the kernel internals are usually welcomed by the developers
27 (before submitting bug reports, please read the documents
28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
29 <file:Documentation/BUG-HUNTING>, and
30 <file:Documentation/oops-tracing.txt> in the kernel source).
32 This option will also make obsoleted drivers available. These are
33 drivers that have been replaced by something else, and/or are
34 scheduled to be removed in a future kernel release.
36 Unless you intend to help test and develop a feature or driver that
37 falls into this category, or you have a situation that requires
38 using these features, you should probably say N here, which will
39 cause the configurator to present you with fewer choices. If
40 you say Y here, you will be offered the choice of using features or
41 drivers that are currently considered to be in the alpha-test phase.
43 config BROKEN
44 bool
46 config BROKEN_ON_SMP
47 bool
48 depends on BROKEN || !SMP
49 default y
51 config LOCK_KERNEL
52 bool
53 depends on SMP || PREEMPT
54 default y
56 config INIT_ENV_ARG_LIMIT
57 int
58 default 32 if !UML
59 default 128 if UML
60 help
61 Maximum of each of the number of arguments and environment
62 variables passed to init from the kernel command line.
65 config LOCALVERSION
66 string "Local version - append to kernel release"
67 help
68 Append an extra string to the end of your kernel version.
69 This will show up when you type uname, for example.
70 The string you set here will be appended after the contents of
71 any files with a filename matching localversion* in your
72 object and source tree, in that order. Your total string can
73 be a maximum of 64 characters.
75 config LOCALVERSION_AUTO
76 bool "Automatically append version information to the version string"
77 default y
78 help
79 This will try to automatically determine if the current tree is a
80 release tree by looking for git tags that belong to the current
81 top of tree revision.
83 A string of the format -gxxxxxxxx will be added to the localversion
84 if a git-based tree is found. The string generated by this will be
85 appended after any matching localversion* files, and after the value
86 set in CONFIG_LOCALVERSION.
88 (The actual string used here is the first eight characters produced
89 by running the command:
91 $ git rev-parse --verify HEAD
93 which is done within the script "scripts/setlocalversion".)
95 config SWAP
96 bool "Support for paging of anonymous memory (swap)"
97 depends on MMU && BLOCK
98 default y
99 help
100 This option allows you to choose whether you want to have support
101 for so called swap devices or swap files in your kernel that are
102 used to provide more virtual memory than the actual RAM present
103 in your computer. If unsure say Y.
105 config SYSVIPC
106 bool "System V IPC"
107 ---help---
108 Inter Process Communication is a suite of library functions and
109 system calls which let processes (running programs) synchronize and
110 exchange information. It is generally considered to be a good thing,
111 and some programs won't run unless you say Y here. In particular, if
112 you want to run the DOS emulator dosemu under Linux (read the
113 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
114 you'll need to say Y here.
116 You can find documentation about IPC with "info ipc" and also in
117 section 6.4 of the Linux Programmer's Guide, available from
118 <http://www.tldp.org/guides.html>.
120 config SYSVIPC_SYSCTL
121 bool
122 depends on SYSVIPC
123 depends on SYSCTL
124 default y
126 config POSIX_MQUEUE
127 bool "POSIX Message Queues"
128 depends on NET && EXPERIMENTAL
129 ---help---
130 POSIX variant of message queues is a part of IPC. In POSIX message
131 queues every message has a priority which decides about succession
132 of receiving it by a process. If you want to compile and run
133 programs written e.g. for Solaris with use of its POSIX message
134 queues (functions mq_*) say Y here.
136 POSIX message queues are visible as a filesystem called 'mqueue'
137 and can be mounted somewhere if you want to do filesystem
138 operations on message queues.
140 If unsure, say Y.
142 config BSD_PROCESS_ACCT
143 bool "BSD Process Accounting"
144 help
145 If you say Y here, a user level program will be able to instruct the
146 kernel (via a special system call) to write process accounting
147 information to a file: whenever a process exits, information about
148 that process will be appended to the file by the kernel. The
149 information includes things such as creation time, owning user,
150 command name, memory usage, controlling terminal etc. (the complete
151 list is in the struct acct in <file:include/linux/acct.h>). It is
152 up to the user level program to do useful things with this
153 information. This is generally a good idea, so say Y.
155 config BSD_PROCESS_ACCT_V3
156 bool "BSD Process Accounting version 3 file format"
157 depends on BSD_PROCESS_ACCT
158 default n
159 help
160 If you say Y here, the process accounting information is written
161 in a new file format that also logs the process IDs of each
162 process and it's parent. Note that this file format is incompatible
163 with previous v0/v1/v2 file formats, so you will need updated tools
164 for processing it. A preliminary version of these tools is available
165 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
167 config TASKSTATS
168 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
169 depends on NET
170 default n
171 help
172 Export selected statistics for tasks/processes through the
173 generic netlink interface. Unlike BSD process accounting, the
174 statistics are available during the lifetime of tasks/processes as
175 responses to commands. Like BSD accounting, they are sent to user
176 space on task exit.
178 Say N if unsure.
180 config TASK_DELAY_ACCT
181 bool "Enable per-task delay accounting (EXPERIMENTAL)"
182 depends on TASKSTATS
183 help
184 Collect information on time spent by a task waiting for system
185 resources like cpu, synchronous block I/O completion and swapping
186 in pages. Such statistics can help in setting a task's priorities
187 relative to other tasks for cpu, io, rss limits etc.
189 Say N if unsure.
191 config TASK_XACCT
192 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
193 depends on TASKSTATS
194 help
195 Collect extended task accounting data and send the data
196 to userland for processing over the taskstats interface.
198 Say N if unsure.
200 config TASK_IO_ACCOUNTING
201 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
202 depends on TASK_XACCT
203 help
204 Collect information on the number of bytes of storage I/O which this
205 task has caused.
207 Say N if unsure.
209 config USER_NS
210 bool "User Namespaces (EXPERIMENTAL)"
211 default n
212 depends on EXPERIMENTAL
213 help
214 Support user namespaces. This allows containers, i.e.
215 vservers, to use user namespaces to provide different
216 user info for different servers. If unsure, say N.
218 config PID_NS
219 bool "PID Namespaces (EXPERIMENTAL)"
220 default n
221 depends on EXPERIMENTAL
222 help
223 Suport process id namespaces. This allows having multiple
224 process with the same pid as long as they are in different
225 pid namespaces. This is a building block of containers.
227 Unless you want to work with an experimental feature
228 say N here.
230 config AUDIT
231 bool "Auditing support"
232 depends on NET
233 help
234 Enable auditing infrastructure that can be used with another
235 kernel subsystem, such as SELinux (which requires this for
236 logging of avc messages output). Does not do system-call
237 auditing without CONFIG_AUDITSYSCALL.
239 config AUDITSYSCALL
240 bool "Enable system-call auditing support"
241 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
242 default y if SECURITY_SELINUX
243 help
244 Enable low-overhead system-call auditing infrastructure that
245 can be used independently or with another kernel subsystem,
246 such as SELinux. To use audit's filesystem watch feature, please
247 ensure that INOTIFY is configured.
249 config AUDIT_TREE
250 def_bool y
251 depends on AUDITSYSCALL && INOTIFY
253 config IKCONFIG
254 tristate "Kernel .config support"
255 ---help---
256 This option enables the complete Linux kernel ".config" file
257 contents to be saved in the kernel. It provides documentation
258 of which kernel options are used in a running kernel or in an
259 on-disk kernel. This information can be extracted from the kernel
260 image file with the script scripts/extract-ikconfig and used as
261 input to rebuild the current kernel or to build another kernel.
262 It can also be extracted from a running kernel by reading
263 /proc/config.gz if enabled (below).
265 config IKCONFIG_PROC
266 bool "Enable access to .config through /proc/config.gz"
267 depends on IKCONFIG && PROC_FS
268 ---help---
269 This option enables access to the kernel configuration file
270 through /proc/config.gz.
272 config LOG_BUF_SHIFT
273 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
274 range 12 21
275 default 17 if S390 || LOCKDEP
276 default 16 if X86_NUMAQ || IA64
277 default 15 if SMP
278 default 14
279 help
280 Select kernel log buffer size as a power of 2.
281 Defaults and Examples:
282 17 => 128 KB for S/390
283 16 => 64 KB for x86 NUMAQ or IA-64
284 15 => 32 KB for SMP
285 14 => 16 KB for uniprocessor
286 13 => 8 KB
287 12 => 4 KB
289 config CGROUPS
290 bool "Control Group support"
291 help
292 This option will let you use process cgroup subsystems
293 such as Cpusets
295 Say N if unsure.
297 config CGROUP_DEBUG
298 bool "Example debug cgroup subsystem"
299 depends on CGROUPS
300 help
301 This option enables a simple cgroup subsystem that
302 exports useful debugging information about the cgroups
303 framework
305 Say N if unsure
307 config CGROUP_NS
308 bool "Namespace cgroup subsystem"
309 depends on CGROUPS
310 help
311 Provides a simple namespace cgroup subsystem to
312 provide hierarchical naming of sets of namespaces,
313 for instance virtual servers and checkpoint/restart
314 jobs.
316 config CPUSETS
317 bool "Cpuset support"
318 depends on SMP && CGROUPS
319 help
320 This option will let you create and manage CPUSETs which
321 allow dynamically partitioning a system into sets of CPUs and
322 Memory Nodes and assigning tasks to run only within those sets.
323 This is primarily useful on large SMP or NUMA systems.
325 Say N if unsure.
327 config FAIR_GROUP_SCHED
328 bool "Fair group CPU scheduler"
329 default y
330 help
331 This feature lets CPU scheduler recognize task groups and control CPU
332 bandwidth allocation to such task groups.
334 choice
335 depends on FAIR_GROUP_SCHED
336 prompt "Basis for grouping tasks"
337 default FAIR_USER_SCHED
339 config FAIR_USER_SCHED
340 bool "user id"
341 help
342 This option will choose userid as the basis for grouping
343 tasks, thus providing equal CPU bandwidth to each user.
345 config FAIR_CGROUP_SCHED
346 bool "Control groups"
347 depends on CGROUPS
348 help
349 This option allows you to create arbitrary task groups
350 using the "cgroup" pseudo filesystem and control
351 the cpu bandwidth allocated to each such task group.
352 Refer to Documentation/cgroups.txt for more information
353 on "cgroup" pseudo filesystem.
355 endchoice
357 config SYSFS_DEPRECATED
358 bool "Create deprecated sysfs files"
359 default y
360 help
361 This option creates deprecated symlinks such as the
362 "device"-link, the <subsystem>:<name>-link, and the
363 "bus"-link. It may also add deprecated key in the
364 uevent environment.
365 None of these features or values should be used today, as
366 they export driver core implementation details to userspace
367 or export properties which can't be kept stable across kernel
368 releases.
370 If enabled, this option will also move any device structures
371 that belong to a class, back into the /sys/class hierarchy, in
372 order to support older versions of udev.
374 If you are using a distro that was released in 2006 or later,
375 it should be safe to say N here.
377 config PROC_PID_CPUSET
378 bool "Include legacy /proc/<pid>/cpuset file"
379 depends on CPUSETS
380 default y
382 config RELAY
383 bool "Kernel->user space relay support (formerly relayfs)"
384 help
385 This option enables support for relay interface support in
386 certain file systems (such as debugfs).
387 It is designed to provide an efficient mechanism for tools and
388 facilities to relay large amounts of data from kernel space to
389 user space.
391 If unsure, say N.
393 config BLK_DEV_INITRD
394 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
395 depends on BROKEN || !FRV
396 help
397 The initial RAM filesystem is a ramfs which is loaded by the
398 boot loader (loadlin or lilo) and that is mounted as root
399 before the normal boot procedure. It is typically used to
400 load modules needed to mount the "real" root file system,
401 etc. See <file:Documentation/initrd.txt> for details.
403 If RAM disk support (BLK_DEV_RAM) is also included, this
404 also enables initial RAM disk (initrd) support and adds
405 15 Kbytes (more on some other architectures) to the kernel size.
407 If unsure say Y.
409 if BLK_DEV_INITRD
411 source "usr/Kconfig"
413 endif
415 config CC_OPTIMIZE_FOR_SIZE
416 bool "Optimize for size (Look out for broken compilers!)"
417 default y
418 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
419 help
420 Enabling this option will pass "-Os" instead of "-O2" to gcc
421 resulting in a smaller kernel.
423 WARNING: some versions of gcc may generate incorrect code with this
424 option. If problems are observed, a gcc upgrade may be needed.
426 If unsure, say N.
428 config SYSCTL
429 bool
431 menuconfig EMBEDDED
432 bool "Configure standard kernel features (for small systems)"
433 help
434 This option allows certain base kernel options and settings
435 to be disabled or tweaked. This is for specialized
436 environments which can tolerate a "non-standard" kernel.
437 Only use this if you really know what you are doing.
439 config UID16
440 bool "Enable 16-bit UID system calls" if EMBEDDED
441 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
442 default y
443 help
444 This enables the legacy 16-bit UID syscall wrappers.
446 config SYSCTL_SYSCALL
447 bool "Sysctl syscall support" if EMBEDDED
448 default y
449 select SYSCTL
450 ---help---
451 sys_sysctl uses binary paths that have been found challenging
452 to properly maintain and use. The interface in /proc/sys
453 using paths with ascii names is now the primary path to this
454 information.
456 Almost nothing using the binary sysctl interface so if you are
457 trying to save some space it is probably safe to disable this,
458 making your kernel marginally smaller.
460 If unsure say Y here.
462 config KALLSYMS
463 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
464 default y
465 help
466 Say Y here to let the kernel print out symbolic crash information and
467 symbolic stack backtraces. This increases the size of the kernel
468 somewhat, as all symbols have to be loaded into the kernel image.
470 config KALLSYMS_ALL
471 bool "Include all symbols in kallsyms"
472 depends on DEBUG_KERNEL && KALLSYMS
473 help
474 Normally kallsyms only contains the symbols of functions, for nicer
475 OOPS messages. Some debuggers can use kallsyms for other
476 symbols too: say Y here to include all symbols, if you need them
477 and you don't care about adding 300k to the size of your kernel.
479 Say N.
481 config KALLSYMS_EXTRA_PASS
482 bool "Do an extra kallsyms pass"
483 depends on KALLSYMS
484 help
485 If kallsyms is not working correctly, the build will fail with
486 inconsistent kallsyms data. If that occurs, log a bug report and
487 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
488 Always say N here unless you find a bug in kallsyms, which must be
489 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
490 you wait for kallsyms to be fixed.
493 config HOTPLUG
494 bool "Support for hot-pluggable devices" if EMBEDDED
495 default y
496 help
497 This option is provided for the case where no hotplug or uevent
498 capabilities is wanted by the kernel. You should only consider
499 disabling this option for embedded systems that do not use modules, a
500 dynamic /dev tree, or dynamic device discovery. Just say Y.
502 config PRINTK
503 default y
504 bool "Enable support for printk" if EMBEDDED
505 help
506 This option enables normal printk support. Removing it
507 eliminates most of the message strings from the kernel image
508 and makes the kernel more or less silent. As this makes it
509 very difficult to diagnose system problems, saying N here is
510 strongly discouraged.
512 config BUG
513 bool "BUG() support" if EMBEDDED
514 default y
515 help
516 Disabling this option eliminates support for BUG and WARN, reducing
517 the size of your kernel image and potentially quietly ignoring
518 numerous fatal conditions. You should only consider disabling this
519 option for embedded systems with no facilities for reporting errors.
520 Just say Y.
522 config ELF_CORE
523 default y
524 bool "Enable ELF core dumps" if EMBEDDED
525 help
526 Enable support for generating core dumps. Disabling saves about 4k.
528 config BASE_FULL
529 default y
530 bool "Enable full-sized data structures for core" if EMBEDDED
531 help
532 Disabling this option reduces the size of miscellaneous core
533 kernel data structures. This saves memory on small machines,
534 but may reduce performance.
536 config FUTEX
537 bool "Enable futex support" if EMBEDDED
538 default y
539 select RT_MUTEXES
540 help
541 Disabling this option will cause the kernel to be built without
542 support for "fast userspace mutexes". The resulting kernel may not
543 run glibc-based applications correctly.
545 config ANON_INODES
546 bool
548 config EPOLL
549 bool "Enable eventpoll support" if EMBEDDED
550 default y
551 select ANON_INODES
552 help
553 Disabling this option will cause the kernel to be built without
554 support for epoll family of system calls.
556 config SIGNALFD
557 bool "Enable signalfd() system call" if EMBEDDED
558 select ANON_INODES
559 default y
560 help
561 Enable the signalfd() system call that allows to receive signals
562 on a file descriptor.
564 If unsure, say Y.
566 config TIMERFD
567 bool "Enable timerfd() system call" if EMBEDDED
568 select ANON_INODES
569 depends on BROKEN
570 default y
571 help
572 Enable the timerfd() system call that allows to receive timer
573 events on a file descriptor.
575 If unsure, say Y.
577 config EVENTFD
578 bool "Enable eventfd() system call" if EMBEDDED
579 select ANON_INODES
580 default y
581 help
582 Enable the eventfd() system call that allows to receive both
583 kernel notification (ie. KAIO) or userspace notifications.
585 If unsure, say Y.
587 config SHMEM
588 bool "Use full shmem filesystem" if EMBEDDED
589 default y
590 depends on MMU
591 help
592 The shmem is an internal filesystem used to manage shared memory.
593 It is backed by swap and manages resource limits. It is also exported
594 to userspace as tmpfs if TMPFS is enabled. Disabling this
595 option replaces shmem and tmpfs with the much simpler ramfs code,
596 which may be appropriate on small systems without swap.
598 config VM_EVENT_COUNTERS
599 default y
600 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
601 help
602 VM event counters are needed for event counts to be shown.
603 This option allows the disabling of the VM event counters
604 on EMBEDDED systems. /proc/vmstat will only show page counts
605 if VM event counters are disabled.
607 config SLUB_DEBUG
608 default y
609 bool "Enable SLUB debugging support" if EMBEDDED
610 depends on SLUB
611 help
612 SLUB has extensive debug support features. Disabling these can
613 result in significant savings in code size. This also disables
614 SLUB sysfs support. /sys/slab will not exist and there will be
615 no support for cache validation etc.
617 choice
618 prompt "Choose SLAB allocator"
619 default SLUB
620 help
621 This option allows to select a slab allocator.
623 config SLAB
624 bool "SLAB"
625 help
626 The regular slab allocator that is established and known to work
627 well in all environments. It organizes cache hot objects in
628 per cpu and per node queues. SLAB is the default choice for
629 a slab allocator.
631 config SLUB
632 bool "SLUB (Unqueued Allocator)"
633 help
634 SLUB is a slab allocator that minimizes cache line usage
635 instead of managing queues of cached objects (SLAB approach).
636 Per cpu caching is realized using slabs of objects instead
637 of queues of objects. SLUB can use memory efficiently
638 and has enhanced diagnostics.
640 config SLOB
641 depends on EMBEDDED
642 bool "SLOB (Simple Allocator)"
643 help
644 SLOB replaces the SLAB allocator with a drastically simpler
645 allocator. SLOB is more space efficient than SLAB but does not
646 scale well (single lock for all operations) and is also highly
647 susceptible to fragmentation. SLUB can accomplish a higher object
648 density. It is usually better to use SLUB instead of SLOB.
650 endchoice
652 endmenu # General setup
654 config RT_MUTEXES
655 boolean
656 select PLIST
658 config TINY_SHMEM
659 default !SHMEM
660 bool
662 config BASE_SMALL
663 int
664 default 0 if BASE_FULL
665 default 1 if !BASE_FULL
667 menuconfig MODULES
668 bool "Enable loadable module support"
669 help
670 Kernel modules are small pieces of compiled code which can
671 be inserted in the running kernel, rather than being
672 permanently built into the kernel. You use the "modprobe"
673 tool to add (and sometimes remove) them. If you say Y here,
674 many parts of the kernel can be built as modules (by
675 answering M instead of Y where indicated): this is most
676 useful for infrequently used options which are not required
677 for booting. For more information, see the man pages for
678 modprobe, lsmod, modinfo, insmod and rmmod.
680 If you say Y here, you will need to run "make
681 modules_install" to put the modules under /lib/modules/
682 where modprobe can find them (you may need to be root to do
683 this).
685 If unsure, say Y.
687 config MODULE_UNLOAD
688 bool "Module unloading"
689 depends on MODULES
690 help
691 Without this option you will not be able to unload any
692 modules (note that some modules may not be unloadable
693 anyway), which makes your kernel slightly smaller and
694 simpler. If unsure, say Y.
696 config MODULE_FORCE_UNLOAD
697 bool "Forced module unloading"
698 depends on MODULE_UNLOAD && EXPERIMENTAL
699 help
700 This option allows you to force a module to unload, even if the
701 kernel believes it is unsafe: the kernel will remove the module
702 without waiting for anyone to stop using it (using the -f option to
703 rmmod). This is mainly for kernel developers and desperate users.
704 If unsure, say N.
706 config MODVERSIONS
707 bool "Module versioning support"
708 depends on MODULES
709 help
710 Usually, you have to use modules compiled with your kernel.
711 Saying Y here makes it sometimes possible to use modules
712 compiled for different kernels, by adding enough information
713 to the modules to (hopefully) spot any changes which would
714 make them incompatible with the kernel you are running. If
715 unsure, say N.
717 config MODULE_SRCVERSION_ALL
718 bool "Source checksum for all modules"
719 depends on MODULES
720 help
721 Modules which contain a MODULE_VERSION get an extra "srcversion"
722 field inserted into their modinfo section, which contains a
723 sum of the source files which made it. This helps maintainers
724 see exactly which source was used to build a module (since
725 others sometimes change the module source without updating
726 the version). With this option, such a "srcversion" field
727 will be created for all modules. If unsure, say N.
729 config KMOD
730 bool "Automatic kernel module loading"
731 depends on MODULES
732 help
733 Normally when you have selected some parts of the kernel to
734 be created as kernel modules, you must load them (using the
735 "modprobe" command) before you can use them. If you say Y
736 here, some parts of the kernel will be able to load modules
737 automatically: when a part of the kernel needs a module, it
738 runs modprobe with the appropriate arguments, thereby
739 loading the module if it is available. If unsure, say Y.
741 config STOP_MACHINE
742 bool
743 default y
744 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
745 help
746 Need stop_machine() primitive.
748 source "block/Kconfig"
750 config PREEMPT_NOTIFIERS
751 bool