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41 drivers that have been replaced by something else, and/or are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 "User Namespaces (EXPERIMENTAL)"
220 depends on EXPERIMENTAL
222 Support user namespaces. This allows containers, i.e.
223 vservers, to use user namespaces to provide different
224 user info for different servers. If unsure, say N.
227 bool "PID Namespaces (EXPERIMENTAL)"
229 depends on EXPERIMENTAL
231 Suport process id namespaces. This allows having multiple
232 process with the same pid as long as they are in different
233 pid namespaces. This is a building block of containers.
235 Unless you want to work with an experimental feature
239 bool "Auditing support"
242 Enable auditing infrastructure that can be used with another
243 kernel subsystem, such as SELinux (which requires this for
244 logging of avc messages output). Does not do system-call
245 auditing without CONFIG_AUDITSYSCALL.
248 bool "Enable system-call auditing support"
249 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
250 default y if SECURITY_SELINUX
252 Enable low-overhead system-call auditing infrastructure that
253 can be used independently or with another kernel subsystem,
254 such as SELinux. To use audit's filesystem watch feature, please
255 ensure that INOTIFY is configured.
259 depends on AUDITSYSCALL && INOTIFY
262 tristate "Kernel .config support"
264 This option enables the complete Linux kernel ".config" file
265 contents to be saved in the kernel. It provides documentation
266 of which kernel options are used in a running kernel or in an
267 on-disk kernel. This information can be extracted from the kernel
268 image file with the script scripts/extract-ikconfig and used as
269 input to rebuild the current kernel or to build another kernel.
270 It can also be extracted from a running kernel by reading
271 /proc/config.gz if enabled (below).
274 bool "Enable access to .config through /proc/config.gz"
275 depends on IKCONFIG && PROC_FS
277 This option enables access to the kernel configuration file
278 through /proc/config.gz.
281 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
283 default 17 if S390 || LOCKDEP
284 default 16 if X86_NUMAQ || IA64
288 Select kernel log buffer size as a power of 2.
289 Defaults and Examples:
290 17 => 128 KB for S/390
291 16 => 64 KB for x86 NUMAQ or IA-64
293 14 => 16 KB for uniprocessor
298 bool "Control Group support"
300 This option will let you use process cgroup subsystems
306 bool "Example debug cgroup subsystem"
309 This option enables a simple cgroup subsystem that
310 exports useful debugging information about the cgroups
316 bool "Namespace cgroup subsystem"
319 Provides a simple namespace cgroup subsystem to
320 provide hierarchical naming of sets of namespaces,
321 for instance virtual servers and checkpoint/restart
325 bool "Cpuset support"
326 depends on SMP && CGROUPS
328 This option will let you create and manage CPUSETs which
329 allow dynamically partitioning a system into sets of CPUs and
330 Memory Nodes and assigning tasks to run only within those sets.
331 This is primarily useful on large SMP or NUMA systems.
335 config FAIR_GROUP_SCHED
336 bool "Fair group CPU scheduler"
339 This feature lets CPU scheduler recognize task groups and control CPU
340 bandwidth allocation to such task groups.
343 depends on FAIR_GROUP_SCHED
344 prompt "Basis for grouping tasks"
345 default FAIR_USER_SCHED
347 config FAIR_USER_SCHED
350 This option will choose userid as the basis for grouping
351 tasks, thus providing equal CPU bandwidth to each user.
353 config FAIR_CGROUP_SCHED
354 bool "Control groups"
357 This option allows you to create arbitrary task groups
358 using the "cgroup" pseudo filesystem and control
359 the cpu bandwidth allocated to each such task group.
360 Refer to Documentation/cgroups.txt for more information
361 on "cgroup" pseudo filesystem.
365 config CGROUP_CPUACCT
366 bool "Simple CPU accounting cgroup subsystem"
369 Provides a simple Resource Controller for monitoring the
370 total CPU consumed by the tasks in a cgroup
372 config RESOURCE_COUNTERS
373 bool "Resource counters"
375 This option enables controller independent resource accounting
376 infrastructure that works with cgroups
379 config SYSFS_DEPRECATED
380 bool "Create deprecated sysfs files"
384 This option creates deprecated symlinks such as the
385 "device"-link, the <subsystem>:<name>-link, and the
386 "bus"-link. It may also add deprecated key in the
388 None of these features or values should be used today, as
389 they export driver core implementation details to userspace
390 or export properties which can't be kept stable across kernel
393 If enabled, this option will also move any device structures
394 that belong to a class, back into the /sys/class hierarchy, in
395 order to support older versions of udev.
397 If you are using a distro that was released in 2006 or later,
398 it should be safe to say N here.
400 config PROC_PID_CPUSET
401 bool "Include legacy /proc/<pid>/cpuset file"
406 bool "Kernel->user space relay support (formerly relayfs)"
408 This option enables support for relay interface support in
409 certain file systems (such as debugfs).
410 It is designed to provide an efficient mechanism for tools and
411 facilities to relay large amounts of data from kernel space to
416 config BLK_DEV_INITRD
417 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
418 depends on BROKEN || !FRV
420 The initial RAM filesystem is a ramfs which is loaded by the
421 boot loader (loadlin or lilo) and that is mounted as root
422 before the normal boot procedure. It is typically used to
423 load modules needed to mount the "real" root file system,
424 etc. See <file:Documentation/initrd.txt> for details.
426 If RAM disk support (BLK_DEV_RAM) is also included, this
427 also enables initial RAM disk (initrd) support and adds
428 15 Kbytes (more on some other architectures) to the kernel size.
438 config CC_OPTIMIZE_FOR_SIZE
439 bool "Optimize for size (Look out for broken compilers!)"
441 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
443 Enabling this option will pass "-Os" instead of "-O2" to gcc
444 resulting in a smaller kernel.
446 WARNING: some versions of gcc may generate incorrect code with this
447 option. If problems are observed, a gcc upgrade may be needed.
455 bool "Configure standard kernel features (for small systems)"
457 This option allows certain base kernel options and settings
458 to be disabled or tweaked. This is for specialized
459 environments which can tolerate a "non-standard" kernel.
460 Only use this if you really know what you are doing.
463 bool "Enable 16-bit UID system calls" if EMBEDDED
464 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
467 This enables the legacy 16-bit UID syscall wrappers.
469 config SYSCTL_SYSCALL
470 bool "Sysctl syscall support" if EMBEDDED
474 sys_sysctl uses binary paths that have been found challenging
475 to properly maintain and use. The interface in /proc/sys
476 using paths with ascii names is now the primary path to this
479 Almost nothing using the binary sysctl interface so if you are
480 trying to save some space it is probably safe to disable this,
481 making your kernel marginally smaller.
483 If unsure say Y here.
486 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
489 Say Y here to let the kernel print out symbolic crash information and
490 symbolic stack backtraces. This increases the size of the kernel
491 somewhat, as all symbols have to be loaded into the kernel image.
494 bool "Include all symbols in kallsyms"
495 depends on DEBUG_KERNEL && KALLSYMS
497 Normally kallsyms only contains the symbols of functions, for nicer
498 OOPS messages. Some debuggers can use kallsyms for other
499 symbols too: say Y here to include all symbols, if you need them
500 and you don't care about adding 300k to the size of your kernel.
504 config KALLSYMS_EXTRA_PASS
505 bool "Do an extra kallsyms pass"
508 If kallsyms is not working correctly, the build will fail with
509 inconsistent kallsyms data. If that occurs, log a bug report and
510 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
511 Always say N here unless you find a bug in kallsyms, which must be
512 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
513 you wait for kallsyms to be fixed.
517 bool "Support for hot-pluggable devices" if EMBEDDED
520 This option is provided for the case where no hotplug or uevent
521 capabilities is wanted by the kernel. You should only consider
522 disabling this option for embedded systems that do not use modules, a
523 dynamic /dev tree, or dynamic device discovery. Just say Y.
527 bool "Enable support for printk" if EMBEDDED
529 This option enables normal printk support. Removing it
530 eliminates most of the message strings from the kernel image
531 and makes the kernel more or less silent. As this makes it
532 very difficult to diagnose system problems, saying N here is
533 strongly discouraged.
536 bool "BUG() support" if EMBEDDED
539 Disabling this option eliminates support for BUG and WARN, reducing
540 the size of your kernel image and potentially quietly ignoring
541 numerous fatal conditions. You should only consider disabling this
542 option for embedded systems with no facilities for reporting errors.
547 bool "Enable ELF core dumps" if EMBEDDED
549 Enable support for generating core dumps. Disabling saves about 4k.
552 bool "Disable heap randomization"
555 Randomizing heap placement makes heap exploits harder, but it
556 also breaks ancient binaries (including anything libc5 based).
557 This option changes the bootup default to heap randomization
558 disabled, and can be overriden runtime by setting
559 /proc/sys/kernel/randomize_va_space to 2.
561 On non-ancient distros (post-2000 ones) Y is usually a safe choice.
565 bool "Enable full-sized data structures for core" if EMBEDDED
567 Disabling this option reduces the size of miscellaneous core
568 kernel data structures. This saves memory on small machines,
569 but may reduce performance.
572 bool "Enable futex support" if EMBEDDED
576 Disabling this option will cause the kernel to be built without
577 support for "fast userspace mutexes". The resulting kernel may not
578 run glibc-based applications correctly.
584 bool "Enable eventpoll support" if EMBEDDED
588 Disabling this option will cause the kernel to be built without
589 support for epoll family of system calls.
592 bool "Enable signalfd() system call" if EMBEDDED
596 Enable the signalfd() system call that allows to receive signals
597 on a file descriptor.
602 bool "Enable timerfd() system call" if EMBEDDED
606 Enable the timerfd() system call that allows to receive timer
607 events on a file descriptor.
612 bool "Enable eventfd() system call" if EMBEDDED
616 Enable the eventfd() system call that allows to receive both
617 kernel notification (ie. KAIO) or userspace notifications.
622 bool "Use full shmem filesystem" if EMBEDDED
626 The shmem is an internal filesystem used to manage shared memory.
627 It is backed by swap and manages resource limits. It is also exported
628 to userspace as tmpfs if TMPFS is enabled. Disabling this
629 option replaces shmem and tmpfs with the much simpler ramfs code,
630 which may be appropriate on small systems without swap.
632 config VM_EVENT_COUNTERS
634 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
636 VM event counters are needed for event counts to be shown.
637 This option allows the disabling of the VM event counters
638 on EMBEDDED systems. /proc/vmstat will only show page counts
639 if VM event counters are disabled.
643 bool "Enable SLUB debugging support" if EMBEDDED
646 SLUB has extensive debug support features. Disabling these can
647 result in significant savings in code size. This also disables
648 SLUB sysfs support. /sys/slab will not exist and there will be
649 no support for cache validation etc.
652 prompt "Choose SLAB allocator"
655 This option allows to select a slab allocator.
660 The regular slab allocator that is established and known to work
661 well in all environments. It organizes cache hot objects in
662 per cpu and per node queues. SLAB is the default choice for
666 bool "SLUB (Unqueued Allocator)"
668 SLUB is a slab allocator that minimizes cache line usage
669 instead of managing queues of cached objects (SLAB approach).
670 Per cpu caching is realized using slabs of objects instead
671 of queues of objects. SLUB can use memory efficiently
672 and has enhanced diagnostics.
676 bool "SLOB (Simple Allocator)"
678 SLOB replaces the stock allocator with a drastically simpler
679 allocator. SLOB is generally more space efficient but
680 does not perform as well on large systems.
685 bool "Profiling support (EXPERIMENTAL)"
687 Say Y here to enable the extended profiling support mechanisms used
688 by profilers such as OProfile.
691 bool "Activate markers"
693 Place an empty function call at each marker site. Can be
694 dynamically changed for a probe function.
696 source "arch/Kconfig"
698 config PROC_PAGE_MONITOR
700 depends on PROC_FS && MMU
701 bool "Enable /proc page monitoring" if EMBEDDED
703 Various /proc files exist to monitor process memory utilization:
704 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
705 /proc/kpagecount, and /proc/kpageflags. Disabling these
706 interfaces will reduce the size of the kernel by approximately 4kb.
708 endmenu # General setup
713 depends on SLAB || SLUB
726 default 0 if BASE_FULL
727 default 1 if !BASE_FULL
730 bool "Enable loadable module support"
732 Kernel modules are small pieces of compiled code which can
733 be inserted in the running kernel, rather than being
734 permanently built into the kernel. You use the "modprobe"
735 tool to add (and sometimes remove) them. If you say Y here,
736 many parts of the kernel can be built as modules (by
737 answering M instead of Y where indicated): this is most
738 useful for infrequently used options which are not required
739 for booting. For more information, see the man pages for
740 modprobe, lsmod, modinfo, insmod and rmmod.
742 If you say Y here, you will need to run "make
743 modules_install" to put the modules under /lib/modules/
744 where modprobe can find them (you may need to be root to do
750 bool "Module unloading"
753 Without this option you will not be able to unload any
754 modules (note that some modules may not be unloadable
755 anyway), which makes your kernel slightly smaller and
756 simpler. If unsure, say Y.
758 config MODULE_FORCE_UNLOAD
759 bool "Forced module unloading"
760 depends on MODULE_UNLOAD && EXPERIMENTAL
762 This option allows you to force a module to unload, even if the
763 kernel believes it is unsafe: the kernel will remove the module
764 without waiting for anyone to stop using it (using the -f option to
765 rmmod). This is mainly for kernel developers and desperate users.
769 bool "Module versioning support"
772 Usually, you have to use modules compiled with your kernel.
773 Saying Y here makes it sometimes possible to use modules
774 compiled for different kernels, by adding enough information
775 to the modules to (hopefully) spot any changes which would
776 make them incompatible with the kernel you are running. If
779 config MODULE_SRCVERSION_ALL
780 bool "Source checksum for all modules"
783 Modules which contain a MODULE_VERSION get an extra "srcversion"
784 field inserted into their modinfo section, which contains a
785 sum of the source files which made it. This helps maintainers
786 see exactly which source was used to build a module (since
787 others sometimes change the module source without updating
788 the version). With this option, such a "srcversion" field
789 will be created for all modules. If unsure, say N.
792 bool "Automatic kernel module loading"
795 Normally when you have selected some parts of the kernel to
796 be created as kernel modules, you must load them (using the
797 "modprobe" command) before you can use them. If you say Y
798 here, some parts of the kernel will be able to load modules
799 automatically: when a part of the kernel needs a module, it
800 runs modprobe with the appropriate arguments, thereby
801 loading the module if it is available. If unsure, say Y.
806 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
808 Need stop_machine() primitive.
810 source "block/Kconfig"
812 config PREEMPT_NOTIFIERS
816 prompt "RCU implementation type:"
819 This allows you to choose either the classic RCU implementation
820 that is designed for best read-side performance on non-realtime
821 systems, or the preemptible RCU implementation for best latency
822 on realtime systems. Note that some kernel preemption modes
823 will restrict your choice.
825 Select the default if you are unsure.
830 This option selects the classic RCU implementation that is
831 designed for best read-side performance on non-realtime
834 Say Y if you are unsure.
837 bool "Preemptible RCU"
840 This option reduces the latency of the kernel by making certain
841 RCU sections preemptible. Normally RCU code is non-preemptible, if
842 this option is selected then read-only RCU sections become
843 preemptible. This helps latency, but may expose bugs due to
844 now-naive assumptions about each RCU read-side critical section
845 remaining on a given CPU through its execution.
847 Say N if you are unsure.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob