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41 drivers that have been replaced by something else, and/or are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 CGROUP_MEM_CONT
401 bool "Memory controller for cgroups"
402 depends on CGROUPS && RESOURCE_COUNTERS
404 Provides a memory controller that manages both page cache and
407 config PROC_PID_CPUSET
408 bool "Include legacy /proc/<pid>/cpuset file"
413 bool "Kernel->user space relay support (formerly relayfs)"
415 This option enables support for relay interface support in
416 certain file systems (such as debugfs).
417 It is designed to provide an efficient mechanism for tools and
418 facilities to relay large amounts of data from kernel space to
424 bool "Namespaces support" if EMBEDDED
427 Provides the way to make tasks work with different objects using
428 the same id. For example same IPC id may refer to different objects
429 or same user id or pid may refer to different tasks when used in
430 different namespaces.
434 depends on NAMESPACES
436 In this namespace tasks see different info provided with the
439 config BLK_DEV_INITRD
440 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
441 depends on BROKEN || !FRV
443 The initial RAM filesystem is a ramfs which is loaded by the
444 boot loader (loadlin or lilo) and that is mounted as root
445 before the normal boot procedure. It is typically used to
446 load modules needed to mount the "real" root file system,
447 etc. See <file:Documentation/initrd.txt> for details.
449 If RAM disk support (BLK_DEV_RAM) is also included, this
450 also enables initial RAM disk (initrd) support and adds
451 15 Kbytes (more on some other architectures) to the kernel size.
461 config CC_OPTIMIZE_FOR_SIZE
462 bool "Optimize for size (Look out for broken compilers!)"
464 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
466 Enabling this option will pass "-Os" instead of "-O2" to gcc
467 resulting in a smaller kernel.
469 WARNING: some versions of gcc may generate incorrect code with this
470 option. If problems are observed, a gcc upgrade may be needed.
478 bool "Configure standard kernel features (for small systems)"
480 This option allows certain base kernel options and settings
481 to be disabled or tweaked. This is for specialized
482 environments which can tolerate a "non-standard" kernel.
483 Only use this if you really know what you are doing.
486 bool "Enable 16-bit UID system calls" if EMBEDDED
487 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
490 This enables the legacy 16-bit UID syscall wrappers.
492 config SYSCTL_SYSCALL
493 bool "Sysctl syscall support" if EMBEDDED
497 sys_sysctl uses binary paths that have been found challenging
498 to properly maintain and use. The interface in /proc/sys
499 using paths with ascii names is now the primary path to this
502 Almost nothing using the binary sysctl interface so if you are
503 trying to save some space it is probably safe to disable this,
504 making your kernel marginally smaller.
506 If unsure say Y here.
509 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
512 Say Y here to let the kernel print out symbolic crash information and
513 symbolic stack backtraces. This increases the size of the kernel
514 somewhat, as all symbols have to be loaded into the kernel image.
517 bool "Include all symbols in kallsyms"
518 depends on DEBUG_KERNEL && KALLSYMS
520 Normally kallsyms only contains the symbols of functions, for nicer
521 OOPS messages. Some debuggers can use kallsyms for other
522 symbols too: say Y here to include all symbols, if you need them
523 and you don't care about adding 300k to the size of your kernel.
527 config KALLSYMS_EXTRA_PASS
528 bool "Do an extra kallsyms pass"
531 If kallsyms is not working correctly, the build will fail with
532 inconsistent kallsyms data. If that occurs, log a bug report and
533 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
534 Always say N here unless you find a bug in kallsyms, which must be
535 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
536 you wait for kallsyms to be fixed.
540 bool "Support for hot-pluggable devices" if EMBEDDED
543 This option is provided for the case where no hotplug or uevent
544 capabilities is wanted by the kernel. You should only consider
545 disabling this option for embedded systems that do not use modules, a
546 dynamic /dev tree, or dynamic device discovery. Just say Y.
550 bool "Enable support for printk" if EMBEDDED
552 This option enables normal printk support. Removing it
553 eliminates most of the message strings from the kernel image
554 and makes the kernel more or less silent. As this makes it
555 very difficult to diagnose system problems, saying N here is
556 strongly discouraged.
559 bool "BUG() support" if EMBEDDED
562 Disabling this option eliminates support for BUG and WARN, reducing
563 the size of your kernel image and potentially quietly ignoring
564 numerous fatal conditions. You should only consider disabling this
565 option for embedded systems with no facilities for reporting errors.
570 bool "Enable ELF core dumps" if EMBEDDED
572 Enable support for generating core dumps. Disabling saves about 4k.
575 bool "Disable heap randomization"
578 Randomizing heap placement makes heap exploits harder, but it
579 also breaks ancient binaries (including anything libc5 based).
580 This option changes the bootup default to heap randomization
581 disabled, and can be overriden runtime by setting
582 /proc/sys/kernel/randomize_va_space to 2.
584 On non-ancient distros (post-2000 ones) Y is usually a safe choice.
588 bool "Enable full-sized data structures for core" if EMBEDDED
590 Disabling this option reduces the size of miscellaneous core
591 kernel data structures. This saves memory on small machines,
592 but may reduce performance.
595 bool "Enable futex support" if EMBEDDED
599 Disabling this option will cause the kernel to be built without
600 support for "fast userspace mutexes". The resulting kernel may not
601 run glibc-based applications correctly.
607 bool "Enable eventpoll support" if EMBEDDED
611 Disabling this option will cause the kernel to be built without
612 support for epoll family of system calls.
615 bool "Enable signalfd() system call" if EMBEDDED
619 Enable the signalfd() system call that allows to receive signals
620 on a file descriptor.
625 bool "Enable timerfd() system call" if EMBEDDED
629 Enable the timerfd() system call that allows to receive timer
630 events on a file descriptor.
635 bool "Enable eventfd() system call" if EMBEDDED
639 Enable the eventfd() system call that allows to receive both
640 kernel notification (ie. KAIO) or userspace notifications.
645 bool "Use full shmem filesystem" if EMBEDDED
649 The shmem is an internal filesystem used to manage shared memory.
650 It is backed by swap and manages resource limits. It is also exported
651 to userspace as tmpfs if TMPFS is enabled. Disabling this
652 option replaces shmem and tmpfs with the much simpler ramfs code,
653 which may be appropriate on small systems without swap.
655 config VM_EVENT_COUNTERS
657 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
659 VM event counters are needed for event counts to be shown.
660 This option allows the disabling of the VM event counters
661 on EMBEDDED systems. /proc/vmstat will only show page counts
662 if VM event counters are disabled.
666 bool "Enable SLUB debugging support" if EMBEDDED
669 SLUB has extensive debug support features. Disabling these can
670 result in significant savings in code size. This also disables
671 SLUB sysfs support. /sys/slab will not exist and there will be
672 no support for cache validation etc.
675 prompt "Choose SLAB allocator"
678 This option allows to select a slab allocator.
683 The regular slab allocator that is established and known to work
684 well in all environments. It organizes cache hot objects in
685 per cpu and per node queues. SLAB is the default choice for
689 bool "SLUB (Unqueued Allocator)"
691 SLUB is a slab allocator that minimizes cache line usage
692 instead of managing queues of cached objects (SLAB approach).
693 Per cpu caching is realized using slabs of objects instead
694 of queues of objects. SLUB can use memory efficiently
695 and has enhanced diagnostics.
699 bool "SLOB (Simple Allocator)"
701 SLOB replaces the stock allocator with a drastically simpler
702 allocator. SLOB is generally more space efficient but
703 does not perform as well on large systems.
708 bool "Profiling support (EXPERIMENTAL)"
710 Say Y here to enable the extended profiling support mechanisms used
711 by profilers such as OProfile.
714 bool "Activate markers"
716 Place an empty function call at each marker site. Can be
717 dynamically changed for a probe function.
719 source "arch/Kconfig"
721 config PROC_PAGE_MONITOR
723 depends on PROC_FS && MMU
724 bool "Enable /proc page monitoring" if EMBEDDED
726 Various /proc files exist to monitor process memory utilization:
727 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
728 /proc/kpagecount, and /proc/kpageflags. Disabling these
729 interfaces will reduce the size of the kernel by approximately 4kb.
731 endmenu # General setup
736 depends on SLAB || SLUB
749 default 0 if BASE_FULL
750 default 1 if !BASE_FULL
753 bool "Enable loadable module support"
755 Kernel modules are small pieces of compiled code which can
756 be inserted in the running kernel, rather than being
757 permanently built into the kernel. You use the "modprobe"
758 tool to add (and sometimes remove) them. If you say Y here,
759 many parts of the kernel can be built as modules (by
760 answering M instead of Y where indicated): this is most
761 useful for infrequently used options which are not required
762 for booting. For more information, see the man pages for
763 modprobe, lsmod, modinfo, insmod and rmmod.
765 If you say Y here, you will need to run "make
766 modules_install" to put the modules under /lib/modules/
767 where modprobe can find them (you may need to be root to do
773 bool "Module unloading"
776 Without this option you will not be able to unload any
777 modules (note that some modules may not be unloadable
778 anyway), which makes your kernel slightly smaller and
779 simpler. If unsure, say Y.
781 config MODULE_FORCE_UNLOAD
782 bool "Forced module unloading"
783 depends on MODULE_UNLOAD && EXPERIMENTAL
785 This option allows you to force a module to unload, even if the
786 kernel believes it is unsafe: the kernel will remove the module
787 without waiting for anyone to stop using it (using the -f option to
788 rmmod). This is mainly for kernel developers and desperate users.
792 bool "Module versioning support"
795 Usually, you have to use modules compiled with your kernel.
796 Saying Y here makes it sometimes possible to use modules
797 compiled for different kernels, by adding enough information
798 to the modules to (hopefully) spot any changes which would
799 make them incompatible with the kernel you are running. If
802 config MODULE_SRCVERSION_ALL
803 bool "Source checksum for all modules"
806 Modules which contain a MODULE_VERSION get an extra "srcversion"
807 field inserted into their modinfo section, which contains a
808 sum of the source files which made it. This helps maintainers
809 see exactly which source was used to build a module (since
810 others sometimes change the module source without updating
811 the version). With this option, such a "srcversion" field
812 will be created for all modules. If unsure, say N.
815 bool "Automatic kernel module loading"
818 Normally when you have selected some parts of the kernel to
819 be created as kernel modules, you must load them (using the
820 "modprobe" command) before you can use them. If you say Y
821 here, some parts of the kernel will be able to load modules
822 automatically: when a part of the kernel needs a module, it
823 runs modprobe with the appropriate arguments, thereby
824 loading the module if it is available. If unsure, say Y.
829 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
831 Need stop_machine() primitive.
833 source "block/Kconfig"
835 config PREEMPT_NOTIFIERS
839 prompt "RCU implementation type:"
842 This allows you to choose either the classic RCU implementation
843 that is designed for best read-side performance on non-realtime
844 systems, or the preemptible RCU implementation for best latency
845 on realtime systems. Note that some kernel preemption modes
846 will restrict your choice.
848 Select the default if you are unsure.
853 This option selects the classic RCU implementation that is
854 designed for best read-side performance on non-realtime
857 Say Y if you are unsure.
860 bool "Preemptible RCU"
863 This option reduces the latency of the kernel by making certain
864 RCU sections preemptible. Normally RCU code is non-preemptible, if
865 this option is selected then read-only RCU sections become
866 preemptible. This helps latency, but may expose bugs due to
867 now-naive assumptions about each RCU read-side critical section
868 remaining on a given CPU through its execution.
870 Say N if you are unsure.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob