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41 drivers that have been replaced by something else, and/or are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)"
262 default 17 if S390 || LOCKDEP
263 default 16 if X86_NUMAQ || IA64
267 Select kernel log buffer size as a power of 2.
268 Defaults and Examples:
269 17 => 128 KB for S/390
270 16 => 64 KB for x86 NUMAQ or IA-64
272 14 => 16 KB for uniprocessor
277 bool "Control Group support"
279 This option will let you use process cgroup subsystems
285 bool "Example debug cgroup subsystem"
288 This option enables a simple cgroup subsystem that
289 exports useful debugging information about the cgroups
295 bool "Namespace cgroup subsystem"
298 Provides a simple namespace cgroup subsystem to
299 provide hierarchical naming of sets of namespaces,
300 for instance virtual servers and checkpoint/restart
304 bool "Cpuset support"
305 depends on SMP && CGROUPS
307 This option will let you create and manage CPUSETs which
308 allow dynamically partitioning a system into sets of CPUs and
309 Memory Nodes and assigning tasks to run only within those sets.
310 This is primarily useful on large SMP or NUMA systems.
315 bool "Group CPU scheduler"
318 This feature lets CPU scheduler recognize task groups and control CPU
319 bandwidth allocation to such task groups.
321 config FAIR_GROUP_SCHED
322 bool "Group scheduling for SCHED_OTHER"
323 depends on GROUP_SCHED
326 config RT_GROUP_SCHED
327 bool "Group scheduling for SCHED_RR/FIFO"
328 depends on EXPERIMENTAL
329 depends on GROUP_SCHED
333 depends on GROUP_SCHED
334 prompt "Basis for grouping tasks"
340 This option will choose userid as the basis for grouping
341 tasks, thus providing equal CPU bandwidth to each user.
344 bool "Control groups"
347 This option allows you to create arbitrary task groups
348 using the "cgroup" pseudo filesystem and control
349 the cpu bandwidth allocated to each such task group.
350 Refer to Documentation/cgroups.txt for more information
351 on "cgroup" pseudo filesystem.
355 config CGROUP_CPUACCT
356 bool "Simple CPU accounting cgroup subsystem"
359 Provides a simple Resource Controller for monitoring the
360 total CPU consumed by the tasks in a cgroup
362 config RESOURCE_COUNTERS
363 bool "Resource counters"
365 This option enables controller independent resource accounting
366 infrastructure that works with cgroups
369 config SYSFS_DEPRECATED
370 bool "Create deprecated sysfs files"
374 This option creates deprecated symlinks such as the
375 "device"-link, the <subsystem>:<name>-link, and the
376 "bus"-link. It may also add deprecated key in the
378 None of these features or values should be used today, as
379 they export driver core implementation details to userspace
380 or export properties which can't be kept stable across kernel
383 If enabled, this option will also move any device structures
384 that belong to a class, back into the /sys/class hierarchy, in
385 order to support older versions of udev.
387 If you are using a distro that was released in 2006 or later,
388 it should be safe to say N here.
390 config CGROUP_MEM_CONT
391 bool "Memory controller for cgroups"
392 depends on CGROUPS && RESOURCE_COUNTERS
394 Provides a memory controller that manages both page cache and
397 config PROC_PID_CPUSET
398 bool "Include legacy /proc/<pid>/cpuset file"
403 bool "Kernel->user space relay support (formerly relayfs)"
405 This option enables support for relay interface support in
406 certain file systems (such as debugfs).
407 It is designed to provide an efficient mechanism for tools and
408 facilities to relay large amounts of data from kernel space to
414 bool "Namespaces support" if EMBEDDED
417 Provides the way to make tasks work with different objects using
418 the same id. For example same IPC id may refer to different objects
419 or same user id or pid may refer to different tasks when used in
420 different namespaces.
424 depends on NAMESPACES
426 In this namespace tasks see different info provided with the
431 depends on NAMESPACES && SYSVIPC
433 In this namespace tasks work with IPC ids which correspond to
434 different IPC objects in different namespaces
437 bool "User namespace (EXPERIMENTAL)"
438 depends on NAMESPACES && EXPERIMENTAL
440 This allows containers, i.e. vservers, to use user namespaces
441 to provide different user info for different servers.
445 bool "PID Namespaces (EXPERIMENTAL)"
447 depends on NAMESPACES && EXPERIMENTAL
449 Suport process id namespaces. This allows having multiple
450 process with the same pid as long as they are in different
451 pid namespaces. This is a building block of containers.
453 Unless you want to work with an experimental feature
456 config BLK_DEV_INITRD
457 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
458 depends on BROKEN || !FRV
460 The initial RAM filesystem is a ramfs which is loaded by the
461 boot loader (loadlin or lilo) and that is mounted as root
462 before the normal boot procedure. It is typically used to
463 load modules needed to mount the "real" root file system,
464 etc. See <file:Documentation/initrd.txt> for details.
466 If RAM disk support (BLK_DEV_RAM) is also included, this
467 also enables initial RAM disk (initrd) support and adds
468 15 Kbytes (more on some other architectures) to the kernel size.
478 config CC_OPTIMIZE_FOR_SIZE
479 bool "Optimize for size (Look out for broken compilers!)"
481 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
483 Enabling this option will pass "-Os" instead of "-O2" to gcc
484 resulting in a smaller kernel.
486 WARNING: some versions of gcc may generate incorrect code with this
487 option. If problems are observed, a gcc upgrade may be needed.
495 bool "Configure standard kernel features (for small systems)"
497 This option allows certain base kernel options and settings
498 to be disabled or tweaked. This is for specialized
499 environments which can tolerate a "non-standard" kernel.
500 Only use this if you really know what you are doing.
503 bool "Enable 16-bit UID system calls" if EMBEDDED
504 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
507 This enables the legacy 16-bit UID syscall wrappers.
509 config SYSCTL_SYSCALL
510 bool "Sysctl syscall support" if EMBEDDED
514 sys_sysctl uses binary paths that have been found challenging
515 to properly maintain and use. The interface in /proc/sys
516 using paths with ascii names is now the primary path to this
519 Almost nothing using the binary sysctl interface so if you are
520 trying to save some space it is probably safe to disable this,
521 making your kernel marginally smaller.
523 If unsure say Y here.
526 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
529 Say Y here to let the kernel print out symbolic crash information and
530 symbolic stack backtraces. This increases the size of the kernel
531 somewhat, as all symbols have to be loaded into the kernel image.
534 bool "Include all symbols in kallsyms"
535 depends on DEBUG_KERNEL && KALLSYMS
537 Normally kallsyms only contains the symbols of functions, for nicer
538 OOPS messages. Some debuggers can use kallsyms for other
539 symbols too: say Y here to include all symbols, if you need them
540 and you don't care about adding 300k to the size of your kernel.
544 config KALLSYMS_EXTRA_PASS
545 bool "Do an extra kallsyms pass"
548 If kallsyms is not working correctly, the build will fail with
549 inconsistent kallsyms data. If that occurs, log a bug report and
550 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
551 Always say N here unless you find a bug in kallsyms, which must be
552 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
553 you wait for kallsyms to be fixed.
557 bool "Support for hot-pluggable devices" if EMBEDDED
560 This option is provided for the case where no hotplug or uevent
561 capabilities is wanted by the kernel. You should only consider
562 disabling this option for embedded systems that do not use modules, a
563 dynamic /dev tree, or dynamic device discovery. Just say Y.
567 bool "Enable support for printk" if EMBEDDED
569 This option enables normal printk support. Removing it
570 eliminates most of the message strings from the kernel image
571 and makes the kernel more or less silent. As this makes it
572 very difficult to diagnose system problems, saying N here is
573 strongly discouraged.
576 bool "BUG() support" if EMBEDDED
579 Disabling this option eliminates support for BUG and WARN, reducing
580 the size of your kernel image and potentially quietly ignoring
581 numerous fatal conditions. You should only consider disabling this
582 option for embedded systems with no facilities for reporting errors.
587 bool "Enable ELF core dumps" if EMBEDDED
589 Enable support for generating core dumps. Disabling saves about 4k.
592 bool "Disable heap randomization"
595 Randomizing heap placement makes heap exploits harder, but it
596 also breaks ancient binaries (including anything libc5 based).
597 This option changes the bootup default to heap randomization
598 disabled, and can be overriden runtime by setting
599 /proc/sys/kernel/randomize_va_space to 2.
601 On non-ancient distros (post-2000 ones) N is usually a safe choice.
605 bool "Enable full-sized data structures for core" if EMBEDDED
607 Disabling this option reduces the size of miscellaneous core
608 kernel data structures. This saves memory on small machines,
609 but may reduce performance.
612 bool "Enable futex support" if EMBEDDED
616 Disabling this option will cause the kernel to be built without
617 support for "fast userspace mutexes". The resulting kernel may not
618 run glibc-based applications correctly.
624 bool "Enable eventpoll support" if EMBEDDED
628 Disabling this option will cause the kernel to be built without
629 support for epoll family of system calls.
632 bool "Enable signalfd() system call" if EMBEDDED
636 Enable the signalfd() system call that allows to receive signals
637 on a file descriptor.
642 bool "Enable timerfd() system call" if EMBEDDED
646 Enable the timerfd() system call that allows to receive timer
647 events on a file descriptor.
652 bool "Enable eventfd() system call" if EMBEDDED
656 Enable the eventfd() system call that allows to receive both
657 kernel notification (ie. KAIO) or userspace notifications.
662 bool "Use full shmem filesystem" if EMBEDDED
666 The shmem is an internal filesystem used to manage shared memory.
667 It is backed by swap and manages resource limits. It is also exported
668 to userspace as tmpfs if TMPFS is enabled. Disabling this
669 option replaces shmem and tmpfs with the much simpler ramfs code,
670 which may be appropriate on small systems without swap.
672 config VM_EVENT_COUNTERS
674 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
676 VM event counters are needed for event counts to be shown.
677 This option allows the disabling of the VM event counters
678 on EMBEDDED systems. /proc/vmstat will only show page counts
679 if VM event counters are disabled.
683 bool "Enable SLUB debugging support" if EMBEDDED
686 SLUB has extensive debug support features. Disabling these can
687 result in significant savings in code size. This also disables
688 SLUB sysfs support. /sys/slab will not exist and there will be
689 no support for cache validation etc.
692 prompt "Choose SLAB allocator"
695 This option allows to select a slab allocator.
700 The regular slab allocator that is established and known to work
701 well in all environments. It organizes cache hot objects in
702 per cpu and per node queues. SLAB is the default choice for
706 bool "SLUB (Unqueued Allocator)"
708 SLUB is a slab allocator that minimizes cache line usage
709 instead of managing queues of cached objects (SLAB approach).
710 Per cpu caching is realized using slabs of objects instead
711 of queues of objects. SLUB can use memory efficiently
712 and has enhanced diagnostics.
716 bool "SLOB (Simple Allocator)"
718 SLOB replaces the stock allocator with a drastically simpler
719 allocator. SLOB is generally more space efficient but
720 does not perform as well on large systems.
725 bool "Profiling support (EXPERIMENTAL)"
727 Say Y here to enable the extended profiling support mechanisms used
728 by profilers such as OProfile.
731 bool "Activate markers"
733 Place an empty function call at each marker site. Can be
734 dynamically changed for a probe function.
736 source "arch/Kconfig"
738 config PROC_PAGE_MONITOR
740 depends on PROC_FS && MMU
741 bool "Enable /proc page monitoring" if EMBEDDED
743 Various /proc files exist to monitor process memory utilization:
744 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
745 /proc/kpagecount, and /proc/kpageflags. Disabling these
746 interfaces will reduce the size of the kernel by approximately 4kb.
748 endmenu # General setup
753 depends on SLAB || SLUB
766 default 0 if BASE_FULL
767 default 1 if !BASE_FULL
770 bool "Enable loadable module support"
772 Kernel modules are small pieces of compiled code which can
773 be inserted in the running kernel, rather than being
774 permanently built into the kernel. You use the "modprobe"
775 tool to add (and sometimes remove) them. If you say Y here,
776 many parts of the kernel can be built as modules (by
777 answering M instead of Y where indicated): this is most
778 useful for infrequently used options which are not required
779 for booting. For more information, see the man pages for
780 modprobe, lsmod, modinfo, insmod and rmmod.
782 If you say Y here, you will need to run "make
783 modules_install" to put the modules under /lib/modules/
784 where modprobe can find them (you may need to be root to do
790 bool "Module unloading"
793 Without this option you will not be able to unload any
794 modules (note that some modules may not be unloadable
795 anyway), which makes your kernel slightly smaller and
796 simpler. If unsure, say Y.
798 config MODULE_FORCE_UNLOAD
799 bool "Forced module unloading"
800 depends on MODULE_UNLOAD && EXPERIMENTAL
802 This option allows you to force a module to unload, even if the
803 kernel believes it is unsafe: the kernel will remove the module
804 without waiting for anyone to stop using it (using the -f option to
805 rmmod). This is mainly for kernel developers and desperate users.
809 bool "Module versioning support"
812 Usually, you have to use modules compiled with your kernel.
813 Saying Y here makes it sometimes possible to use modules
814 compiled for different kernels, by adding enough information
815 to the modules to (hopefully) spot any changes which would
816 make them incompatible with the kernel you are running. If
819 config MODULE_SRCVERSION_ALL
820 bool "Source checksum for all modules"
823 Modules which contain a MODULE_VERSION get an extra "srcversion"
824 field inserted into their modinfo section, which contains a
825 sum of the source files which made it. This helps maintainers
826 see exactly which source was used to build a module (since
827 others sometimes change the module source without updating
828 the version). With this option, such a "srcversion" field
829 will be created for all modules. If unsure, say N.
832 bool "Automatic kernel module loading"
835 Normally when you have selected some parts of the kernel to
836 be created as kernel modules, you must load them (using the
837 "modprobe" command) before you can use them. If you say Y
838 here, some parts of the kernel will be able to load modules
839 automatically: when a part of the kernel needs a module, it
840 runs modprobe with the appropriate arguments, thereby
841 loading the module if it is available. If unsure, say Y.
846 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
848 Need stop_machine() primitive.
850 source "block/Kconfig"
852 config PREEMPT_NOTIFIERS
856 prompt "RCU implementation type:"
859 This allows you to choose either the classic RCU implementation
860 that is designed for best read-side performance on non-realtime
861 systems, or the preemptible RCU implementation for best latency
862 on realtime systems. Note that some kernel preemption modes
863 will restrict your choice.
865 Select the default if you are unsure.
870 This option selects the classic RCU implementation that is
871 designed for best read-side performance on non-realtime
874 Say Y if you are unsure.
877 bool "Preemptible RCU"
880 This option reduces the latency of the kernel by making certain
881 RCU sections preemptible. Normally RCU code is non-preemptible, if
882 this option is selected then read-only RCU sections become
883 preemptible. This helps latency, but may expose bugs due to
884 now-naive assumptions about each RCU read-side critical section
885 remaining on a given CPU through its execution.
887 Say N if you are unsure.
projects / linux-2.6 / blob