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41 drivers that have been replaced by something else, and/or are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
372 config SYSFS_DEPRECATED_V2
373 bool "Create deprecated sysfs files"
376 select SYSFS_DEPRECATED
378 This option creates deprecated symlinks such as the
379 "device"-link, the <subsystem>:<name>-link, and the
380 "bus"-link. It may also add deprecated key in the
382 None of these features or values should be used today, as
383 they export driver core implementation details to userspace
384 or export properties which can't be kept stable across kernel
387 If enabled, this option will also move any device structures
388 that belong to a class, back into the /sys/class hierarchy, in
389 order to support older versions of udev and some userspace
392 If you are using a distro with the most recent userspace
393 packages, it should be safe to say N here.
395 config CGROUP_MEM_CONT
396 bool "Memory controller for cgroups"
397 depends on CGROUPS && RESOURCE_COUNTERS
399 Provides a memory controller that manages both page cache and
402 Note that setting this option increases fixed memory overhead
403 associated with each page of memory in the system by 4/8 bytes
404 and also increases cache misses because struct page on many 64bit
405 systems will not fit into a single cache line anymore.
407 Only enable when you're ok with these trade offs and really
408 sure you need the memory controller.
410 config PROC_PID_CPUSET
411 bool "Include legacy /proc/<pid>/cpuset file"
416 bool "Kernel->user space relay support (formerly relayfs)"
418 This option enables support for relay interface support in
419 certain file systems (such as debugfs).
420 It is designed to provide an efficient mechanism for tools and
421 facilities to relay large amounts of data from kernel space to
427 bool "Namespaces support" if EMBEDDED
430 Provides the way to make tasks work with different objects using
431 the same id. For example same IPC id may refer to different objects
432 or same user id or pid may refer to different tasks when used in
433 different namespaces.
437 depends on NAMESPACES
439 In this namespace tasks see different info provided with the
444 depends on NAMESPACES && SYSVIPC
446 In this namespace tasks work with IPC ids which correspond to
447 different IPC objects in different namespaces
450 bool "User namespace (EXPERIMENTAL)"
451 depends on NAMESPACES && EXPERIMENTAL
453 This allows containers, i.e. vservers, to use user namespaces
454 to provide different user info for different servers.
458 bool "PID Namespaces (EXPERIMENTAL)"
460 depends on NAMESPACES && EXPERIMENTAL
462 Suport process id namespaces. This allows having multiple
463 process with the same pid as long as they are in different
464 pid namespaces. This is a building block of containers.
466 Unless you want to work with an experimental feature
469 config BLK_DEV_INITRD
470 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
471 depends on BROKEN || !FRV
473 The initial RAM filesystem is a ramfs which is loaded by the
474 boot loader (loadlin or lilo) and that is mounted as root
475 before the normal boot procedure. It is typically used to
476 load modules needed to mount the "real" root file system,
477 etc. See <file:Documentation/initrd.txt> for details.
479 If RAM disk support (BLK_DEV_RAM) is also included, this
480 also enables initial RAM disk (initrd) support and adds
481 15 Kbytes (more on some other architectures) to the kernel size.
491 config CC_OPTIMIZE_FOR_SIZE
492 bool "Optimize for size (Look out for broken compilers!)"
494 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
496 Enabling this option will pass "-Os" instead of "-O2" to gcc
497 resulting in a smaller kernel.
499 WARNING: some versions of gcc may generate incorrect code with this
500 option. If problems are observed, a gcc upgrade may be needed.
508 bool "Configure standard kernel features (for small systems)"
510 This option allows certain base kernel options and settings
511 to be disabled or tweaked. This is for specialized
512 environments which can tolerate a "non-standard" kernel.
513 Only use this if you really know what you are doing.
516 bool "Enable 16-bit UID system calls" if EMBEDDED
517 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
520 This enables the legacy 16-bit UID syscall wrappers.
522 config SYSCTL_SYSCALL
523 bool "Sysctl syscall support" if EMBEDDED
527 sys_sysctl uses binary paths that have been found challenging
528 to properly maintain and use. The interface in /proc/sys
529 using paths with ascii names is now the primary path to this
532 Almost nothing using the binary sysctl interface so if you are
533 trying to save some space it is probably safe to disable this,
534 making your kernel marginally smaller.
536 If unsure say Y here.
539 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
542 Say Y here to let the kernel print out symbolic crash information and
543 symbolic stack backtraces. This increases the size of the kernel
544 somewhat, as all symbols have to be loaded into the kernel image.
547 bool "Include all symbols in kallsyms"
548 depends on DEBUG_KERNEL && KALLSYMS
550 Normally kallsyms only contains the symbols of functions, for nicer
551 OOPS messages. Some debuggers can use kallsyms for other
552 symbols too: say Y here to include all symbols, if you need them
553 and you don't care about adding 300k to the size of your kernel.
557 config KALLSYMS_EXTRA_PASS
558 bool "Do an extra kallsyms pass"
561 If kallsyms is not working correctly, the build will fail with
562 inconsistent kallsyms data. If that occurs, log a bug report and
563 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
564 Always say N here unless you find a bug in kallsyms, which must be
565 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
566 you wait for kallsyms to be fixed.
570 bool "Support for hot-pluggable devices" if EMBEDDED
573 This option is provided for the case where no hotplug or uevent
574 capabilities is wanted by the kernel. You should only consider
575 disabling this option for embedded systems that do not use modules, a
576 dynamic /dev tree, or dynamic device discovery. Just say Y.
580 bool "Enable support for printk" if EMBEDDED
582 This option enables normal printk support. Removing it
583 eliminates most of the message strings from the kernel image
584 and makes the kernel more or less silent. As this makes it
585 very difficult to diagnose system problems, saying N here is
586 strongly discouraged.
589 bool "BUG() support" if EMBEDDED
592 Disabling this option eliminates support for BUG and WARN, reducing
593 the size of your kernel image and potentially quietly ignoring
594 numerous fatal conditions. You should only consider disabling this
595 option for embedded systems with no facilities for reporting errors.
600 bool "Enable ELF core dumps" if EMBEDDED
602 Enable support for generating core dumps. Disabling saves about 4k.
605 bool "Disable heap randomization"
608 Randomizing heap placement makes heap exploits harder, but it
609 also breaks ancient binaries (including anything libc5 based).
610 This option changes the bootup default to heap randomization
611 disabled, and can be overriden runtime by setting
612 /proc/sys/kernel/randomize_va_space to 2.
614 On non-ancient distros (post-2000 ones) N is usually a safe choice.
618 bool "Enable full-sized data structures for core" if EMBEDDED
620 Disabling this option reduces the size of miscellaneous core
621 kernel data structures. This saves memory on small machines,
622 but may reduce performance.
625 bool "Enable futex support" if EMBEDDED
629 Disabling this option will cause the kernel to be built without
630 support for "fast userspace mutexes". The resulting kernel may not
631 run glibc-based applications correctly.
637 bool "Enable eventpoll support" if EMBEDDED
641 Disabling this option will cause the kernel to be built without
642 support for epoll family of system calls.
645 bool "Enable signalfd() system call" if EMBEDDED
649 Enable the signalfd() system call that allows to receive signals
650 on a file descriptor.
655 bool "Enable timerfd() system call" if EMBEDDED
659 Enable the timerfd() system call that allows to receive timer
660 events on a file descriptor.
665 bool "Enable eventfd() system call" if EMBEDDED
669 Enable the eventfd() system call that allows to receive both
670 kernel notification (ie. KAIO) or userspace notifications.
675 bool "Use full shmem filesystem" if EMBEDDED
679 The shmem is an internal filesystem used to manage shared memory.
680 It is backed by swap and manages resource limits. It is also exported
681 to userspace as tmpfs if TMPFS is enabled. Disabling this
682 option replaces shmem and tmpfs with the much simpler ramfs code,
683 which may be appropriate on small systems without swap.
685 config VM_EVENT_COUNTERS
687 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
689 VM event counters are needed for event counts to be shown.
690 This option allows the disabling of the VM event counters
691 on EMBEDDED systems. /proc/vmstat will only show page counts
692 if VM event counters are disabled.
696 bool "Enable SLUB debugging support" if EMBEDDED
699 SLUB has extensive debug support features. Disabling these can
700 result in significant savings in code size. This also disables
701 SLUB sysfs support. /sys/slab will not exist and there will be
702 no support for cache validation etc.
705 prompt "Choose SLAB allocator"
708 This option allows to select a slab allocator.
713 The regular slab allocator that is established and known to work
714 well in all environments. It organizes cache hot objects in
715 per cpu and per node queues. SLAB is the default choice for
719 bool "SLUB (Unqueued Allocator)"
721 SLUB is a slab allocator that minimizes cache line usage
722 instead of managing queues of cached objects (SLAB approach).
723 Per cpu caching is realized using slabs of objects instead
724 of queues of objects. SLUB can use memory efficiently
725 and has enhanced diagnostics.
729 bool "SLOB (Simple Allocator)"
731 SLOB replaces the stock allocator with a drastically simpler
732 allocator. SLOB is generally more space efficient but
733 does not perform as well on large systems.
738 bool "Profiling support (EXPERIMENTAL)"
740 Say Y here to enable the extended profiling support mechanisms used
741 by profilers such as OProfile.
744 bool "Activate markers"
746 Place an empty function call at each marker site. Can be
747 dynamically changed for a probe function.
749 source "arch/Kconfig"
751 config PROC_PAGE_MONITOR
753 depends on PROC_FS && MMU
754 bool "Enable /proc page monitoring" if EMBEDDED
756 Various /proc files exist to monitor process memory utilization:
757 /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
758 /proc/kpagecount, and /proc/kpageflags. Disabling these
759 interfaces will reduce the size of the kernel by approximately 4kb.
761 endmenu # General setup
766 depends on SLAB || SLUB
779 default 0 if BASE_FULL
780 default 1 if !BASE_FULL
783 bool "Enable loadable module support"
785 Kernel modules are small pieces of compiled code which can
786 be inserted in the running kernel, rather than being
787 permanently built into the kernel. You use the "modprobe"
788 tool to add (and sometimes remove) them. If you say Y here,
789 many parts of the kernel can be built as modules (by
790 answering M instead of Y where indicated): this is most
791 useful for infrequently used options which are not required
792 for booting. For more information, see the man pages for
793 modprobe, lsmod, modinfo, insmod and rmmod.
795 If you say Y here, you will need to run "make
796 modules_install" to put the modules under /lib/modules/
797 where modprobe can find them (you may need to be root to do
803 bool "Module unloading"
806 Without this option you will not be able to unload any
807 modules (note that some modules may not be unloadable
808 anyway), which makes your kernel slightly smaller and
809 simpler. If unsure, say Y.
811 config MODULE_FORCE_UNLOAD
812 bool "Forced module unloading"
813 depends on MODULE_UNLOAD && EXPERIMENTAL
815 This option allows you to force a module to unload, even if the
816 kernel believes it is unsafe: the kernel will remove the module
817 without waiting for anyone to stop using it (using the -f option to
818 rmmod). This is mainly for kernel developers and desperate users.
822 bool "Module versioning support"
825 Usually, you have to use modules compiled with your kernel.
826 Saying Y here makes it sometimes possible to use modules
827 compiled for different kernels, by adding enough information
828 to the modules to (hopefully) spot any changes which would
829 make them incompatible with the kernel you are running. If
832 config MODULE_SRCVERSION_ALL
833 bool "Source checksum for all modules"
836 Modules which contain a MODULE_VERSION get an extra "srcversion"
837 field inserted into their modinfo section, which contains a
838 sum of the source files which made it. This helps maintainers
839 see exactly which source was used to build a module (since
840 others sometimes change the module source without updating
841 the version). With this option, such a "srcversion" field
842 will be created for all modules. If unsure, say N.
845 bool "Automatic kernel module loading"
848 Normally when you have selected some parts of the kernel to
849 be created as kernel modules, you must load them (using the
850 "modprobe" command) before you can use them. If you say Y
851 here, some parts of the kernel will be able to load modules
852 automatically: when a part of the kernel needs a module, it
853 runs modprobe with the appropriate arguments, thereby
854 loading the module if it is available. If unsure, say Y.
859 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
861 Need stop_machine() primitive.
863 source "block/Kconfig"
865 config PREEMPT_NOTIFIERS
869 prompt "RCU implementation type:"
872 This allows you to choose either the classic RCU implementation
873 that is designed for best read-side performance on non-realtime
874 systems, or the preemptible RCU implementation for best latency
875 on realtime systems. Note that some kernel preemption modes
876 will restrict your choice.
878 Select the default if you are unsure.
883 This option selects the classic RCU implementation that is
884 designed for best read-side performance on non-realtime
887 Say Y if you are unsure.
890 bool "Preemptible RCU"
893 This option reduces the latency of the kernel by making certain
894 RCU sections preemptible. Normally RCU code is non-preemptible, if
895 this option is selected then read-only RCU sections become
896 preemptible. This helps latency, but may expose bugs due to
897 now-naive assumptions about each RCU read-side critical section
898 remaining on a given CPU through its execution.
900 Say N if you are unsure.
projects / linux-2.6 / blob