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41 drivers that have been replaced by something else, and/or are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"
327 depends on EXPERIMENTAL
330 This feature lets CPU scheduler recognize task groups and control CPU
331 bandwidth allocation to such task groups.
333 config FAIR_GROUP_SCHED
334 bool "Group scheduling for SCHED_OTHER"
335 depends on GROUP_SCHED
338 config RT_GROUP_SCHED
339 bool "Group scheduling for SCHED_RR/FIFO"
340 depends on EXPERIMENTAL
341 depends on GROUP_SCHED
344 This feature lets you explicitly allocate real CPU bandwidth
345 to users or control groups (depending on the "Basis for grouping tasks"
346 setting below. If enabled, it will also make it impossible to
347 schedule realtime tasks for non-root users until you allocate
348 realtime bandwidth for them.
349 See Documentation/sched-rt-group.txt for more information.
352 depends on GROUP_SCHED
353 prompt "Basis for grouping tasks"
359 This option will choose userid as the basis for grouping
360 tasks, thus providing equal CPU bandwidth to each user.
363 bool "Control groups"
366 This option allows you to create arbitrary task groups
367 using the "cgroup" pseudo filesystem and control
368 the cpu bandwidth allocated to each such task group.
369 Refer to Documentation/cgroups.txt for more information
370 on "cgroup" pseudo filesystem.
374 config CGROUP_CPUACCT
375 bool "Simple CPU accounting cgroup subsystem"
378 Provides a simple Resource Controller for monitoring the
379 total CPU consumed by the tasks in a cgroup
381 config RESOURCE_COUNTERS
382 bool "Resource counters"
384 This option enables controller independent resource accounting
385 infrastructure that works with cgroups
391 config CGROUP_MEM_RES_CTLR
392 bool "Memory Resource Controller for Control Groups"
393 depends on CGROUPS && RESOURCE_COUNTERS
396 Provides a memory resource controller that manages both page cache and
399 Note that setting this option increases fixed memory overhead
400 associated with each page of memory in the system by 4/8 bytes
401 and also increases cache misses because struct page on many 64bit
402 systems will not fit into a single cache line anymore.
404 Only enable when you're ok with these trade offs and really
405 sure you need the memory resource controller.
407 This config option also selects MM_OWNER config option, which
408 could in turn add some fork/exit overhead.
410 config SYSFS_DEPRECATED
413 config SYSFS_DEPRECATED_V2
414 bool "Create deprecated sysfs files"
417 select SYSFS_DEPRECATED
419 This option creates deprecated symlinks such as the
420 "device"-link, the <subsystem>:<name>-link, and the
421 "bus"-link. It may also add deprecated key in the
423 None of these features or values should be used today, as
424 they export driver core implementation details to userspace
425 or export properties which can't be kept stable across kernel
428 If enabled, this option will also move any device structures
429 that belong to a class, back into the /sys/class hierarchy, in
430 order to support older versions of udev and some userspace
433 If you are using a distro with the most recent userspace
434 packages, it should be safe to say N here.
436 config PROC_PID_CPUSET
437 bool "Include legacy /proc/<pid>/cpuset file"
442 bool "Kernel->user space relay support (formerly relayfs)"
444 This option enables support for relay interface support in
445 certain file systems (such as debugfs).
446 It is designed to provide an efficient mechanism for tools and
447 facilities to relay large amounts of data from kernel space to
453 bool "Namespaces support" if EMBEDDED
456 Provides the way to make tasks work with different objects using
457 the same id. For example same IPC id may refer to different objects
458 or same user id or pid may refer to different tasks when used in
459 different namespaces.
463 depends on NAMESPACES
465 In this namespace tasks see different info provided with the
470 depends on NAMESPACES && SYSVIPC
472 In this namespace tasks work with IPC ids which correspond to
473 different IPC objects in different namespaces
476 bool "User namespace (EXPERIMENTAL)"
477 depends on NAMESPACES && EXPERIMENTAL
479 This allows containers, i.e. vservers, to use user namespaces
480 to provide different user info for different servers.
484 bool "PID Namespaces (EXPERIMENTAL)"
486 depends on NAMESPACES && EXPERIMENTAL
488 Suport process id namespaces. This allows having multiple
489 process with the same pid as long as they are in different
490 pid namespaces. This is a building block of containers.
492 Unless you want to work with an experimental feature
495 config BLK_DEV_INITRD
496 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
497 depends on BROKEN || !FRV
499 The initial RAM filesystem is a ramfs which is loaded by the
500 boot loader (loadlin or lilo) and that is mounted as root
501 before the normal boot procedure. It is typically used to
502 load modules needed to mount the "real" root file system,
503 etc. See <file:Documentation/initrd.txt> for details.
505 If RAM disk support (BLK_DEV_RAM) is also included, this
506 also enables initial RAM disk (initrd) support and adds
507 15 Kbytes (more on some other architectures) to the kernel size.
517 config CC_OPTIMIZE_FOR_SIZE
518 bool "Optimize for size"
521 Enabling this option will pass "-Os" instead of "-O2" to gcc
522 resulting in a smaller kernel.
530 bool "Configure standard kernel features (for small systems)"
532 This option allows certain base kernel options and settings
533 to be disabled or tweaked. This is for specialized
534 environments which can tolerate a "non-standard" kernel.
535 Only use this if you really know what you are doing.
538 bool "Enable 16-bit UID system calls" if EMBEDDED
539 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
542 This enables the legacy 16-bit UID syscall wrappers.
544 config SYSCTL_SYSCALL
545 bool "Sysctl syscall support" if EMBEDDED
549 sys_sysctl uses binary paths that have been found challenging
550 to properly maintain and use. The interface in /proc/sys
551 using paths with ascii names is now the primary path to this
554 Almost nothing using the binary sysctl interface so if you are
555 trying to save some space it is probably safe to disable this,
556 making your kernel marginally smaller.
558 If unsure say Y here.
560 config SYSCTL_SYSCALL_CHECK
561 bool "Sysctl checks" if EMBEDDED
562 depends on SYSCTL_SYSCALL
565 sys_sysctl uses binary paths that have been found challenging
566 to properly maintain and use. This enables checks that help
567 you to keep things correct.
569 If unsure say Y here.
572 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
575 Say Y here to let the kernel print out symbolic crash information and
576 symbolic stack backtraces. This increases the size of the kernel
577 somewhat, as all symbols have to be loaded into the kernel image.
580 bool "Include all symbols in kallsyms"
581 depends on DEBUG_KERNEL && KALLSYMS
583 Normally kallsyms only contains the symbols of functions, for nicer
584 OOPS messages. Some debuggers can use kallsyms for other
585 symbols too: say Y here to include all symbols, if you need them
586 and you don't care about adding 300k to the size of your kernel.
590 config KALLSYMS_EXTRA_PASS
591 bool "Do an extra kallsyms pass"
594 If kallsyms is not working correctly, the build will fail with
595 inconsistent kallsyms data. If that occurs, log a bug report and
596 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
597 Always say N here unless you find a bug in kallsyms, which must be
598 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
599 you wait for kallsyms to be fixed.
603 bool "Support for hot-pluggable devices" if EMBEDDED
606 This option is provided for the case where no hotplug or uevent
607 capabilities is wanted by the kernel. You should only consider
608 disabling this option for embedded systems that do not use modules, a
609 dynamic /dev tree, or dynamic device discovery. Just say Y.
613 bool "Enable support for printk" if EMBEDDED
615 This option enables normal printk support. Removing it
616 eliminates most of the message strings from the kernel image
617 and makes the kernel more or less silent. As this makes it
618 very difficult to diagnose system problems, saying N here is
619 strongly discouraged.
622 bool "BUG() support" if EMBEDDED
625 Disabling this option eliminates support for BUG and WARN, reducing
626 the size of your kernel image and potentially quietly ignoring
627 numerous fatal conditions. You should only consider disabling this
628 option for embedded systems with no facilities for reporting errors.
633 bool "Enable ELF core dumps" if EMBEDDED
635 Enable support for generating core dumps. Disabling saves about 4k.
638 bool "Disable heap randomization"
641 Randomizing heap placement makes heap exploits harder, but it
642 also breaks ancient binaries (including anything libc5 based).
643 This option changes the bootup default to heap randomization
644 disabled, and can be overriden runtime by setting
645 /proc/sys/kernel/randomize_va_space to 2.
647 On non-ancient distros (post-2000 ones) N is usually a safe choice.
651 bool "Enable full-sized data structures for core" if EMBEDDED
653 Disabling this option reduces the size of miscellaneous core
654 kernel data structures. This saves memory on small machines,
655 but may reduce performance.
658 bool "Enable futex support" if EMBEDDED
662 Disabling this option will cause the kernel to be built without
663 support for "fast userspace mutexes". The resulting kernel may not
664 run glibc-based applications correctly.
670 bool "Enable eventpoll support" if EMBEDDED
674 Disabling this option will cause the kernel to be built without
675 support for epoll family of system calls.
678 bool "Enable signalfd() system call" if EMBEDDED
682 Enable the signalfd() system call that allows to receive signals
683 on a file descriptor.
688 bool "Enable timerfd() system call" if EMBEDDED
692 Enable the timerfd() system call that allows to receive timer
693 events on a file descriptor.
698 bool "Enable eventfd() system call" if EMBEDDED
702 Enable the eventfd() system call that allows to receive both
703 kernel notification (ie. KAIO) or userspace notifications.
708 bool "Use full shmem filesystem" if EMBEDDED
712 The shmem is an internal filesystem used to manage shared memory.
713 It is backed by swap and manages resource limits. It is also exported
714 to userspace as tmpfs if TMPFS is enabled. Disabling this
715 option replaces shmem and tmpfs with the much simpler ramfs code,
716 which may be appropriate on small systems without swap.
718 config VM_EVENT_COUNTERS
720 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
722 VM event counters are needed for event counts to be shown.
723 This option allows the disabling of the VM event counters
724 on EMBEDDED systems. /proc/vmstat will only show page counts
725 if VM event counters are disabled.
729 bool "Enable SLUB debugging support" if EMBEDDED
730 depends on SLUB && SYSFS
732 SLUB has extensive debug support features. Disabling these can
733 result in significant savings in code size. This also disables
734 SLUB sysfs support. /sys/slab will not exist and there will be
735 no support for cache validation etc.
738 prompt "Choose SLAB allocator"
741 This option allows to select a slab allocator.
746 The regular slab allocator that is established and known to work
747 well in all environments. It organizes cache hot objects in
748 per cpu and per node queues. SLAB is the default choice for
752 bool "SLUB (Unqueued Allocator)"
754 SLUB is a slab allocator that minimizes cache line usage
755 instead of managing queues of cached objects (SLAB approach).
756 Per cpu caching is realized using slabs of objects instead
757 of queues of objects. SLUB can use memory efficiently
758 and has enhanced diagnostics.
762 bool "SLOB (Simple Allocator)"
764 SLOB replaces the stock allocator with a drastically simpler
765 allocator. SLOB is generally more space efficient but
766 does not perform as well on large systems.
771 bool "Profiling support (EXPERIMENTAL)"
773 Say Y here to enable the extended profiling support mechanisms used
774 by profilers such as OProfile.
777 bool "Activate markers"
779 Place an empty function call at each marker site. Can be
780 dynamically changed for a probe function.
782 source "arch/Kconfig"
784 config PROC_PAGE_MONITOR
786 depends on PROC_FS && MMU
787 bool "Enable /proc page monitoring" if EMBEDDED
789 Various /proc files exist to monitor process memory utilization:
790 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
791 /proc/kpagecount, and /proc/kpageflags. Disabling these
792 interfaces will reduce the size of the kernel by approximately 4kb.
794 endmenu # General setup
799 depends on SLAB || SLUB_DEBUG
812 default 0 if BASE_FULL
813 default 1 if !BASE_FULL
816 bool "Enable loadable module support"
818 Kernel modules are small pieces of compiled code which can
819 be inserted in the running kernel, rather than being
820 permanently built into the kernel. You use the "modprobe"
821 tool to add (and sometimes remove) them. If you say Y here,
822 many parts of the kernel can be built as modules (by
823 answering M instead of Y where indicated): this is most
824 useful for infrequently used options which are not required
825 for booting. For more information, see the man pages for
826 modprobe, lsmod, modinfo, insmod and rmmod.
828 If you say Y here, you will need to run "make
829 modules_install" to put the modules under /lib/modules/
830 where modprobe can find them (you may need to be root to do
835 config MODULE_FORCE_LOAD
836 bool "Forced module loading"
840 This option allows loading of modules even if that would set the
841 'F' (forced) taint, due to lack of version info. Which is
842 usually a really bad idea.
845 bool "Module unloading"
848 Without this option you will not be able to unload any
849 modules (note that some modules may not be unloadable
850 anyway), which makes your kernel slightly smaller and
851 simpler. If unsure, say Y.
853 config MODULE_FORCE_UNLOAD
854 bool "Forced module unloading"
855 depends on MODULE_UNLOAD && EXPERIMENTAL
857 This option allows you to force a module to unload, even if the
858 kernel believes it is unsafe: the kernel will remove the module
859 without waiting for anyone to stop using it (using the -f option to
860 rmmod). This is mainly for kernel developers and desperate users.
864 bool "Module versioning support"
867 Usually, you have to use modules compiled with your kernel.
868 Saying Y here makes it sometimes possible to use modules
869 compiled for different kernels, by adding enough information
870 to the modules to (hopefully) spot any changes which would
871 make them incompatible with the kernel you are running. If
874 config MODULE_SRCVERSION_ALL
875 bool "Source checksum for all modules"
878 Modules which contain a MODULE_VERSION get an extra "srcversion"
879 field inserted into their modinfo section, which contains a
880 sum of the source files which made it. This helps maintainers
881 see exactly which source was used to build a module (since
882 others sometimes change the module source without updating
883 the version). With this option, such a "srcversion" field
884 will be created for all modules. If unsure, say N.
887 bool "Automatic kernel module loading"
890 Normally when you have selected some parts of the kernel to
891 be created as kernel modules, you must load them (using the
892 "modprobe" command) before you can use them. If you say Y
893 here, some parts of the kernel will be able to load modules
894 automatically: when a part of the kernel needs a module, it
895 runs modprobe with the appropriate arguments, thereby
896 loading the module if it is available. If unsure, say Y.
901 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
903 Need stop_machine() primitive.
905 source "block/Kconfig"
907 config PREEMPT_NOTIFIERS
911 def_bool !PREEMPT_RCU
913 This option selects the classic RCU implementation that is
914 designed for best read-side performance on non-realtime
915 systems. Classic RCU is the default. Note that the
916 PREEMPT_RCU symbol is used to select/deselect this option.
projects / linux-2.6 / blob