7 option env="KERNELVERSION"
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "arch/$ARCH/defconfig"
21 bool "Prompt for development and/or incomplete code/drivers"
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41 drivers that have been replaced by something else, and/or are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.
56 depends on BROKEN || !SMP
61 depends on SMP || PREEMPT
64 config INIT_ENV_ARG_LIMIT
69 Maximum of each of the number of arguments and environment
70 variables passed to init from the kernel command line.
74 string "Local version - append to kernel release"
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"
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
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".)
104 bool "Support for paging of anonymous memory (swap)"
105 depends on MMU && BLOCK
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.
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
135 bool "POSIX Message Queues"
136 depends on NET && EXPERIMENTAL
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.
150 config BSD_PROCESS_ACCT
151 bool "BSD Process Accounting"
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
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/>.
176 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
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
188 config TASK_DELAY_ACCT
189 bool "Enable per-task delay accounting (EXPERIMENTAL)"
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.
200 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
203 Collect extended task accounting data and send the data
204 to userland for processing over the taskstats interface.
208 config TASK_IO_ACCOUNTING
209 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
210 depends on TASK_XACCT
212 Collect information on the number of bytes of storage I/O which this
218 bool "Auditing support"
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.
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
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.
238 depends on AUDITSYSCALL && INOTIFY
241 tristate "Kernel .config support"
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).
253 bool "Enable access to .config through /proc/config.gz"
254 depends on IKCONFIG && PROC_FS
256 This option enables access to the kernel configuration file
257 through /proc/config.gz.
260 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
264 Select kernel log buffer size as a power of 2.
274 bool "Control Group support"
276 This option will let you use process cgroup subsystems
282 bool "Example debug cgroup subsystem"
286 This option enables a simple cgroup subsystem that
287 exports useful debugging information about the cgroups
293 bool "Namespace cgroup subsystem"
296 Provides a simple namespace cgroup subsystem to
297 provide hierarchical naming of sets of namespaces,
298 for instance virtual servers and checkpoint/restart
302 bool "Device controller for cgroups"
303 depends on CGROUPS && EXPERIMENTAL
305 Provides a cgroup implementing whitelists for devices which
306 a process in the cgroup can mknod or open.
309 bool "Cpuset support"
310 depends on SMP && CGROUPS
312 This option will let you create and manage CPUSETs which
313 allow dynamically partitioning a system into sets of CPUs and
314 Memory Nodes and assigning tasks to run only within those sets.
315 This is primarily useful on large SMP or NUMA systems.
320 # Architectures with an unreliable sched_clock() should select this:
322 config HAVE_UNSTABLE_SCHED_CLOCK
326 bool "Group CPU scheduler"
329 This feature lets CPU scheduler recognize task groups and control CPU
330 bandwidth allocation to such task groups.
332 config FAIR_GROUP_SCHED
333 bool "Group scheduling for SCHED_OTHER"
334 depends on GROUP_SCHED
337 config RT_GROUP_SCHED
338 bool "Group scheduling for SCHED_RR/FIFO"
339 depends on EXPERIMENTAL
340 depends on GROUP_SCHED
343 This feature lets you explicitly allocate real CPU bandwidth
344 to users or control groups (depending on the "Basis for grouping tasks"
345 setting below. If enabled, it will also make it impossible to
346 schedule realtime tasks for non-root users until you allocate
347 realtime bandwidth for them.
348 See Documentation/sched-rt-group.txt for more information.
351 depends on GROUP_SCHED
352 prompt "Basis for grouping tasks"
358 This option will choose userid as the basis for grouping
359 tasks, thus providing equal CPU bandwidth to each user.
362 bool "Control groups"
365 This option allows you to create arbitrary task groups
366 using the "cgroup" pseudo filesystem and control
367 the cpu bandwidth allocated to each such task group.
368 Refer to Documentation/cgroups.txt for more information
369 on "cgroup" pseudo filesystem.
373 config CGROUP_CPUACCT
374 bool "Simple CPU accounting cgroup subsystem"
377 Provides a simple Resource Controller for monitoring the
378 total CPU consumed by the tasks in a cgroup
380 config RESOURCE_COUNTERS
381 bool "Resource counters"
383 This option enables controller independent resource accounting
384 infrastructure that works with cgroups
390 config CGROUP_MEM_RES_CTLR
391 bool "Memory Resource Controller for Control Groups"
392 depends on CGROUPS && RESOURCE_COUNTERS
395 Provides a memory resource controller that manages both page cache and
398 Note that setting this option increases fixed memory overhead
399 associated with each page of memory in the system by 4/8 bytes
400 and also increases cache misses because struct page on many 64bit
401 systems will not fit into a single cache line anymore.
403 Only enable when you're ok with these trade offs and really
404 sure you need the memory resource controller.
406 This config option also selects MM_OWNER config option, which
407 could in turn add some fork/exit overhead.
409 config SYSFS_DEPRECATED
412 config SYSFS_DEPRECATED_V2
413 bool "Create deprecated sysfs files"
416 select SYSFS_DEPRECATED
418 This option creates deprecated symlinks such as the
419 "device"-link, the <subsystem>:<name>-link, and the
420 "bus"-link. It may also add deprecated key in the
422 None of these features or values should be used today, as
423 they export driver core implementation details to userspace
424 or export properties which can't be kept stable across kernel
427 If enabled, this option will also move any device structures
428 that belong to a class, back into the /sys/class hierarchy, in
429 order to support older versions of udev and some userspace
432 If you are using a distro with the most recent userspace
433 packages, it should be safe to say N here.
435 config PROC_PID_CPUSET
436 bool "Include legacy /proc/<pid>/cpuset file"
441 bool "Kernel->user space relay support (formerly relayfs)"
443 This option enables support for relay interface support in
444 certain file systems (such as debugfs).
445 It is designed to provide an efficient mechanism for tools and
446 facilities to relay large amounts of data from kernel space to
452 bool "Namespaces support" if EMBEDDED
455 Provides the way to make tasks work with different objects using
456 the same id. For example same IPC id may refer to different objects
457 or same user id or pid may refer to different tasks when used in
458 different namespaces.
462 depends on NAMESPACES
464 In this namespace tasks see different info provided with the
469 depends on NAMESPACES && SYSVIPC
471 In this namespace tasks work with IPC ids which correspond to
472 different IPC objects in different namespaces
475 bool "User namespace (EXPERIMENTAL)"
476 depends on NAMESPACES && EXPERIMENTAL
478 This allows containers, i.e. vservers, to use user namespaces
479 to provide different user info for different servers.
483 bool "PID Namespaces (EXPERIMENTAL)"
485 depends on NAMESPACES && EXPERIMENTAL
487 Suport process id namespaces. This allows having multiple
488 process with the same pid as long as they are in different
489 pid namespaces. This is a building block of containers.
491 Unless you want to work with an experimental feature
494 config BLK_DEV_INITRD
495 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
496 depends on BROKEN || !FRV
498 The initial RAM filesystem is a ramfs which is loaded by the
499 boot loader (loadlin or lilo) and that is mounted as root
500 before the normal boot procedure. It is typically used to
501 load modules needed to mount the "real" root file system,
502 etc. See <file:Documentation/initrd.txt> for details.
504 If RAM disk support (BLK_DEV_RAM) is also included, this
505 also enables initial RAM disk (initrd) support and adds
506 15 Kbytes (more on some other architectures) to the kernel size.
516 config CC_OPTIMIZE_FOR_SIZE
517 bool "Optimize for size"
520 Enabling this option will pass "-Os" instead of "-O2" to gcc
521 resulting in a smaller kernel.
529 bool "Configure standard kernel features (for small systems)"
531 This option allows certain base kernel options and settings
532 to be disabled or tweaked. This is for specialized
533 environments which can tolerate a "non-standard" kernel.
534 Only use this if you really know what you are doing.
537 bool "Enable 16-bit UID system calls" if EMBEDDED
538 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
541 This enables the legacy 16-bit UID syscall wrappers.
543 config SYSCTL_SYSCALL
544 bool "Sysctl syscall support" if EMBEDDED
548 sys_sysctl uses binary paths that have been found challenging
549 to properly maintain and use. The interface in /proc/sys
550 using paths with ascii names is now the primary path to this
553 Almost nothing using the binary sysctl interface so if you are
554 trying to save some space it is probably safe to disable this,
555 making your kernel marginally smaller.
557 If unsure say Y here.
559 config SYSCTL_SYSCALL_CHECK
560 bool "Sysctl checks" if EMBEDDED
561 depends on SYSCTL_SYSCALL
564 sys_sysctl uses binary paths that have been found challenging
565 to properly maintain and use. This enables checks that help
566 you to keep things correct.
568 If unsure say Y here.
571 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
574 Say Y here to let the kernel print out symbolic crash information and
575 symbolic stack backtraces. This increases the size of the kernel
576 somewhat, as all symbols have to be loaded into the kernel image.
579 bool "Include all symbols in kallsyms"
580 depends on DEBUG_KERNEL && KALLSYMS
582 Normally kallsyms only contains the symbols of functions, for nicer
583 OOPS messages. Some debuggers can use kallsyms for other
584 symbols too: say Y here to include all symbols, if you need them
585 and you don't care about adding 300k to the size of your kernel.
589 config KALLSYMS_EXTRA_PASS
590 bool "Do an extra kallsyms pass"
593 If kallsyms is not working correctly, the build will fail with
594 inconsistent kallsyms data. If that occurs, log a bug report and
595 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
596 Always say N here unless you find a bug in kallsyms, which must be
597 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
598 you wait for kallsyms to be fixed.
602 bool "Support for hot-pluggable devices" if EMBEDDED
605 This option is provided for the case where no hotplug or uevent
606 capabilities is wanted by the kernel. You should only consider
607 disabling this option for embedded systems that do not use modules, a
608 dynamic /dev tree, or dynamic device discovery. Just say Y.
612 bool "Enable support for printk" if EMBEDDED
614 This option enables normal printk support. Removing it
615 eliminates most of the message strings from the kernel image
616 and makes the kernel more or less silent. As this makes it
617 very difficult to diagnose system problems, saying N here is
618 strongly discouraged.
621 bool "BUG() support" if EMBEDDED
624 Disabling this option eliminates support for BUG and WARN, reducing
625 the size of your kernel image and potentially quietly ignoring
626 numerous fatal conditions. You should only consider disabling this
627 option for embedded systems with no facilities for reporting errors.
632 bool "Enable ELF core dumps" if EMBEDDED
634 Enable support for generating core dumps. Disabling saves about 4k.
637 bool "Disable heap randomization"
640 Randomizing heap placement makes heap exploits harder, but it
641 also breaks ancient binaries (including anything libc5 based).
642 This option changes the bootup default to heap randomization
643 disabled, and can be overriden runtime by setting
644 /proc/sys/kernel/randomize_va_space to 2.
646 On non-ancient distros (post-2000 ones) N is usually a safe choice.
650 bool "Enable full-sized data structures for core" if EMBEDDED
652 Disabling this option reduces the size of miscellaneous core
653 kernel data structures. This saves memory on small machines,
654 but may reduce performance.
657 bool "Enable futex support" if EMBEDDED
661 Disabling this option will cause the kernel to be built without
662 support for "fast userspace mutexes". The resulting kernel may not
663 run glibc-based applications correctly.
669 bool "Enable eventpoll support" if EMBEDDED
673 Disabling this option will cause the kernel to be built without
674 support for epoll family of system calls.
677 bool "Enable signalfd() system call" if EMBEDDED
681 Enable the signalfd() system call that allows to receive signals
682 on a file descriptor.
687 bool "Enable timerfd() system call" if EMBEDDED
691 Enable the timerfd() system call that allows to receive timer
692 events on a file descriptor.
697 bool "Enable eventfd() system call" if EMBEDDED
701 Enable the eventfd() system call that allows to receive both
702 kernel notification (ie. KAIO) or userspace notifications.
707 bool "Use full shmem filesystem" if EMBEDDED
711 The shmem is an internal filesystem used to manage shared memory.
712 It is backed by swap and manages resource limits. It is also exported
713 to userspace as tmpfs if TMPFS is enabled. Disabling this
714 option replaces shmem and tmpfs with the much simpler ramfs code,
715 which may be appropriate on small systems without swap.
717 config VM_EVENT_COUNTERS
719 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
721 VM event counters are needed for event counts to be shown.
722 This option allows the disabling of the VM event counters
723 on EMBEDDED systems. /proc/vmstat will only show page counts
724 if VM event counters are disabled.
728 bool "Enable SLUB debugging support" if EMBEDDED
729 depends on SLUB && SYSFS
731 SLUB has extensive debug support features. Disabling these can
732 result in significant savings in code size. This also disables
733 SLUB sysfs support. /sys/slab will not exist and there will be
734 no support for cache validation etc.
737 prompt "Choose SLAB allocator"
740 This option allows to select a slab allocator.
745 The regular slab allocator that is established and known to work
746 well in all environments. It organizes cache hot objects in
747 per cpu and per node queues. SLAB is the default choice for
751 bool "SLUB (Unqueued Allocator)"
753 SLUB is a slab allocator that minimizes cache line usage
754 instead of managing queues of cached objects (SLAB approach).
755 Per cpu caching is realized using slabs of objects instead
756 of queues of objects. SLUB can use memory efficiently
757 and has enhanced diagnostics.
761 bool "SLOB (Simple Allocator)"
763 SLOB replaces the stock allocator with a drastically simpler
764 allocator. SLOB is generally more space efficient but
765 does not perform as well on large systems.
770 bool "Profiling support (EXPERIMENTAL)"
772 Say Y here to enable the extended profiling support mechanisms used
773 by profilers such as OProfile.
776 bool "Activate markers"
778 Place an empty function call at each marker site. Can be
779 dynamically changed for a probe function.
781 source "arch/Kconfig"
783 config PROC_PAGE_MONITOR
785 depends on PROC_FS && MMU
786 bool "Enable /proc page monitoring" if EMBEDDED
788 Various /proc files exist to monitor process memory utilization:
789 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
790 /proc/kpagecount, and /proc/kpageflags. Disabling these
791 interfaces will reduce the size of the kernel by approximately 4kb.
793 endmenu # General setup
798 depends on SLAB || SLUB_DEBUG
811 default 0 if BASE_FULL
812 default 1 if !BASE_FULL
815 bool "Enable loadable module support"
817 Kernel modules are small pieces of compiled code which can
818 be inserted in the running kernel, rather than being
819 permanently built into the kernel. You use the "modprobe"
820 tool to add (and sometimes remove) them. If you say Y here,
821 many parts of the kernel can be built as modules (by
822 answering M instead of Y where indicated): this is most
823 useful for infrequently used options which are not required
824 for booting. For more information, see the man pages for
825 modprobe, lsmod, modinfo, insmod and rmmod.
827 If you say Y here, you will need to run "make
828 modules_install" to put the modules under /lib/modules/
829 where modprobe can find them (you may need to be root to do
834 config MODULE_FORCE_LOAD
835 bool "Forced module loading"
839 This option allows loading of modules even if that would set the
840 'F' (forced) taint, due to lack of version info. Which is
841 usually a really bad idea.
844 bool "Module unloading"
847 Without this option you will not be able to unload any
848 modules (note that some modules may not be unloadable
849 anyway), which makes your kernel slightly smaller and
850 simpler. If unsure, say Y.
852 config MODULE_FORCE_UNLOAD
853 bool "Forced module unloading"
854 depends on MODULE_UNLOAD && EXPERIMENTAL
856 This option allows you to force a module to unload, even if the
857 kernel believes it is unsafe: the kernel will remove the module
858 without waiting for anyone to stop using it (using the -f option to
859 rmmod). This is mainly for kernel developers and desperate users.
863 bool "Module versioning support"
866 Usually, you have to use modules compiled with your kernel.
867 Saying Y here makes it sometimes possible to use modules
868 compiled for different kernels, by adding enough information
869 to the modules to (hopefully) spot any changes which would
870 make them incompatible with the kernel you are running. If
873 config MODULE_SRCVERSION_ALL
874 bool "Source checksum for all modules"
877 Modules which contain a MODULE_VERSION get an extra "srcversion"
878 field inserted into their modinfo section, which contains a
879 sum of the source files which made it. This helps maintainers
880 see exactly which source was used to build a module (since
881 others sometimes change the module source without updating
882 the version). With this option, such a "srcversion" field
883 will be created for all modules. If unsure, say N.
886 bool "Automatic kernel module loading"
889 Normally when you have selected some parts of the kernel to
890 be created as kernel modules, you must load them (using the
891 "modprobe" command) before you can use them. If you say Y
892 here, some parts of the kernel will be able to load modules
893 automatically: when a part of the kernel needs a module, it
894 runs modprobe with the appropriate arguments, thereby
895 loading the module if it is available. If unsure, say Y.
900 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
902 Need stop_machine() primitive.
904 source "block/Kconfig"
906 config PREEMPT_NOTIFIERS
910 def_bool !PREEMPT_RCU
912 This option selects the classic RCU implementation that is
913 designed for best read-side performance on non-realtime
914 systems. Classic RCU is the default. Note that the
915 PREEMPT_RCU symbol is used to select/deselect this option.
projects / linux-2.6 / blob