7 option env="KERNELVERSION"
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "$ARCH_DEFCONFIG"
17 default "arch/$ARCH/defconfig"
22 bool "Prompt for development and/or incomplete code/drivers"
24 Some of the various things that Linux supports (such as network
25 drivers, file systems, network protocols, etc.) can be in a state
26 of development where the functionality, stability, or the level of
27 testing is not yet high enough for general use. This is usually
28 known as the "alpha-test" phase among developers. If a feature is
29 currently in alpha-test, then the developers usually discourage
30 uninformed widespread use of this feature by the general public to
31 avoid "Why doesn't this work?" type mail messages. However, active
32 testing and use of these systems is welcomed. Just be aware that it
33 may not meet the normal level of reliability or it may fail to work
34 in some special cases. Detailed bug reports from people familiar
35 with the kernel internals are usually welcomed by the developers
36 (before submitting bug reports, please read the documents
37 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
38 <file:Documentation/BUG-HUNTING>, and
39 <file:Documentation/oops-tracing.txt> in the kernel source).
41 This option will also make obsoleted drivers available. These are
42 drivers that have been replaced by something else, and/or are
43 scheduled to be removed in a future kernel release.
45 Unless you intend to help test and develop a feature or driver that
46 falls into this category, or you have a situation that requires
47 using these features, you should probably say N here, which will
48 cause the configurator to present you with fewer choices. If
49 you say Y here, you will be offered the choice of using features or
50 drivers that are currently considered to be in the alpha-test phase.
57 depends on BROKEN || !SMP
62 depends on SMP || PREEMPT
65 config INIT_ENV_ARG_LIMIT
70 Maximum of each of the number of arguments and environment
71 variables passed to init from the kernel command line.
75 string "Local version - append to kernel release"
77 Append an extra string to the end of your kernel version.
78 This will show up when you type uname, for example.
79 The string you set here will be appended after the contents of
80 any files with a filename matching localversion* in your
81 object and source tree, in that order. Your total string can
82 be a maximum of 64 characters.
84 config LOCALVERSION_AUTO
85 bool "Automatically append version information to the version string"
88 This will try to automatically determine if the current tree is a
89 release tree by looking for git tags that belong to the current
92 A string of the format -gxxxxxxxx will be added to the localversion
93 if a git-based tree is found. The string generated by this will be
94 appended after any matching localversion* files, and after the value
95 set in CONFIG_LOCALVERSION.
97 (The actual string used here is the first eight characters produced
98 by running the command:
100 $ git rev-parse --verify HEAD
102 which is done within the script "scripts/setlocalversion".)
105 bool "Support for paging of anonymous memory (swap)"
106 depends on MMU && BLOCK
109 This option allows you to choose whether you want to have support
110 for so called swap devices or swap files in your kernel that are
111 used to provide more virtual memory than the actual RAM present
112 in your computer. If unsure say Y.
117 Inter Process Communication is a suite of library functions and
118 system calls which let processes (running programs) synchronize and
119 exchange information. It is generally considered to be a good thing,
120 and some programs won't run unless you say Y here. In particular, if
121 you want to run the DOS emulator dosemu under Linux (read the
122 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
123 you'll need to say Y here.
125 You can find documentation about IPC with "info ipc" and also in
126 section 6.4 of the Linux Programmer's Guide, available from
127 <http://www.tldp.org/guides.html>.
129 config SYSVIPC_SYSCTL
136 bool "POSIX Message Queues"
137 depends on NET && EXPERIMENTAL
139 POSIX variant of message queues is a part of IPC. In POSIX message
140 queues every message has a priority which decides about succession
141 of receiving it by a process. If you want to compile and run
142 programs written e.g. for Solaris with use of its POSIX message
143 queues (functions mq_*) say Y here.
145 POSIX message queues are visible as a filesystem called 'mqueue'
146 and can be mounted somewhere if you want to do filesystem
147 operations on message queues.
151 config BSD_PROCESS_ACCT
152 bool "BSD Process Accounting"
154 If you say Y here, a user level program will be able to instruct the
155 kernel (via a special system call) to write process accounting
156 information to a file: whenever a process exits, information about
157 that process will be appended to the file by the kernel. The
158 information includes things such as creation time, owning user,
159 command name, memory usage, controlling terminal etc. (the complete
160 list is in the struct acct in <file:include/linux/acct.h>). It is
161 up to the user level program to do useful things with this
162 information. This is generally a good idea, so say Y.
164 config BSD_PROCESS_ACCT_V3
165 bool "BSD Process Accounting version 3 file format"
166 depends on BSD_PROCESS_ACCT
169 If you say Y here, the process accounting information is written
170 in a new file format that also logs the process IDs of each
171 process and it's parent. Note that this file format is incompatible
172 with previous v0/v1/v2 file formats, so you will need updated tools
173 for processing it. A preliminary version of these tools is available
174 at <http://www.gnu.org/software/acct/>.
177 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
181 Export selected statistics for tasks/processes through the
182 generic netlink interface. Unlike BSD process accounting, the
183 statistics are available during the lifetime of tasks/processes as
184 responses to commands. Like BSD accounting, they are sent to user
189 config TASK_DELAY_ACCT
190 bool "Enable per-task delay accounting (EXPERIMENTAL)"
193 Collect information on time spent by a task waiting for system
194 resources like cpu, synchronous block I/O completion and swapping
195 in pages. Such statistics can help in setting a task's priorities
196 relative to other tasks for cpu, io, rss limits etc.
201 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
204 Collect extended task accounting data and send the data
205 to userland for processing over the taskstats interface.
209 config TASK_IO_ACCOUNTING
210 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
211 depends on TASK_XACCT
213 Collect information on the number of bytes of storage I/O which this
219 bool "Auditing support"
222 Enable auditing infrastructure that can be used with another
223 kernel subsystem, such as SELinux (which requires this for
224 logging of avc messages output). Does not do system-call
225 auditing without CONFIG_AUDITSYSCALL.
228 bool "Enable system-call auditing support"
229 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
230 default y if SECURITY_SELINUX
232 Enable low-overhead system-call auditing infrastructure that
233 can be used independently or with another kernel subsystem,
234 such as SELinux. To use audit's filesystem watch feature, please
235 ensure that INOTIFY is configured.
239 depends on AUDITSYSCALL && INOTIFY
242 tristate "Kernel .config support"
244 This option enables the complete Linux kernel ".config" file
245 contents to be saved in the kernel. It provides documentation
246 of which kernel options are used in a running kernel or in an
247 on-disk kernel. This information can be extracted from the kernel
248 image file with the script scripts/extract-ikconfig and used as
249 input to rebuild the current kernel or to build another kernel.
250 It can also be extracted from a running kernel by reading
251 /proc/config.gz if enabled (below).
254 bool "Enable access to .config through /proc/config.gz"
255 depends on IKCONFIG && PROC_FS
257 This option enables access to the kernel configuration file
258 through /proc/config.gz.
261 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
265 Select kernel log buffer size as a power of 2.
275 bool "Control Group support"
277 This option will let you use process cgroup subsystems
283 bool "Example debug cgroup subsystem"
287 This option enables a simple cgroup subsystem that
288 exports useful debugging information about the cgroups
294 bool "Namespace cgroup subsystem"
297 Provides a simple namespace cgroup subsystem to
298 provide hierarchical naming of sets of namespaces,
299 for instance virtual servers and checkpoint/restart
303 bool "Device controller for cgroups"
304 depends on CGROUPS && EXPERIMENTAL
306 Provides a cgroup implementing whitelists for devices which
307 a process in the cgroup can mknod or open.
310 bool "Cpuset support"
311 depends on SMP && CGROUPS
313 This option will let you create and manage CPUSETs which
314 allow dynamically partitioning a system into sets of CPUs and
315 Memory Nodes and assigning tasks to run only within those sets.
316 This is primarily useful on large SMP or NUMA systems.
321 # Architectures with an unreliable sched_clock() should select this:
323 config HAVE_UNSTABLE_SCHED_CLOCK
327 bool "Group CPU scheduler"
328 depends on EXPERIMENTAL
331 This feature lets CPU scheduler recognize task groups and control CPU
332 bandwidth allocation to such task groups.
334 config FAIR_GROUP_SCHED
335 bool "Group scheduling for SCHED_OTHER"
336 depends on GROUP_SCHED
339 config RT_GROUP_SCHED
340 bool "Group scheduling for SCHED_RR/FIFO"
341 depends on EXPERIMENTAL
342 depends on GROUP_SCHED
345 This feature lets you explicitly allocate real CPU bandwidth
346 to users or control groups (depending on the "Basis for grouping tasks"
347 setting below. If enabled, it will also make it impossible to
348 schedule realtime tasks for non-root users until you allocate
349 realtime bandwidth for them.
350 See Documentation/sched-rt-group.txt for more information.
353 depends on GROUP_SCHED
354 prompt "Basis for grouping tasks"
360 This option will choose userid as the basis for grouping
361 tasks, thus providing equal CPU bandwidth to each user.
364 bool "Control groups"
367 This option allows you to create arbitrary task groups
368 using the "cgroup" pseudo filesystem and control
369 the cpu bandwidth allocated to each such task group.
370 Refer to Documentation/cgroups.txt for more information
371 on "cgroup" pseudo filesystem.
375 config CGROUP_CPUACCT
376 bool "Simple CPU accounting cgroup subsystem"
379 Provides a simple Resource Controller for monitoring the
380 total CPU consumed by the tasks in a cgroup
382 config RESOURCE_COUNTERS
383 bool "Resource counters"
385 This option enables controller independent resource accounting
386 infrastructure that works with cgroups
392 config CGROUP_MEM_RES_CTLR
393 bool "Memory Resource Controller for Control Groups"
394 depends on CGROUPS && RESOURCE_COUNTERS
397 Provides a memory resource controller that manages both page cache and
400 Note that setting this option increases fixed memory overhead
401 associated with each page of memory in the system by 4/8 bytes
402 and also increases cache misses because struct page on many 64bit
403 systems will not fit into a single cache line anymore.
405 Only enable when you're ok with these trade offs and really
406 sure you need the memory resource controller.
408 This config option also selects MM_OWNER config option, which
409 could in turn add some fork/exit overhead.
411 config SYSFS_DEPRECATED
414 config SYSFS_DEPRECATED_V2
415 bool "Create deprecated sysfs files"
418 select SYSFS_DEPRECATED
420 This option creates deprecated symlinks such as the
421 "device"-link, the <subsystem>:<name>-link, and the
422 "bus"-link. It may also add deprecated key in the
424 None of these features or values should be used today, as
425 they export driver core implementation details to userspace
426 or export properties which can't be kept stable across kernel
429 If enabled, this option will also move any device structures
430 that belong to a class, back into the /sys/class hierarchy, in
431 order to support older versions of udev and some userspace
434 If you are using a distro with the most recent userspace
435 packages, it should be safe to say N here.
437 config PROC_PID_CPUSET
438 bool "Include legacy /proc/<pid>/cpuset file"
443 bool "Kernel->user space relay support (formerly relayfs)"
445 This option enables support for relay interface support in
446 certain file systems (such as debugfs).
447 It is designed to provide an efficient mechanism for tools and
448 facilities to relay large amounts of data from kernel space to
454 bool "Namespaces support" if EMBEDDED
457 Provides the way to make tasks work with different objects using
458 the same id. For example same IPC id may refer to different objects
459 or same user id or pid may refer to different tasks when used in
460 different namespaces.
464 depends on NAMESPACES
466 In this namespace tasks see different info provided with the
471 depends on NAMESPACES && SYSVIPC
473 In this namespace tasks work with IPC ids which correspond to
474 different IPC objects in different namespaces
477 bool "User namespace (EXPERIMENTAL)"
478 depends on NAMESPACES && EXPERIMENTAL
480 This allows containers, i.e. vservers, to use user namespaces
481 to provide different user info for different servers.
485 bool "PID Namespaces (EXPERIMENTAL)"
487 depends on NAMESPACES && EXPERIMENTAL
489 Support process id namespaces. This allows having multiple
490 process with the same pid as long as they are in different
491 pid namespaces. This is a building block of containers.
493 Unless you want to work with an experimental feature
496 config BLK_DEV_INITRD
497 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
498 depends on BROKEN || !FRV
500 The initial RAM filesystem is a ramfs which is loaded by the
501 boot loader (loadlin or lilo) and that is mounted as root
502 before the normal boot procedure. It is typically used to
503 load modules needed to mount the "real" root file system,
504 etc. See <file:Documentation/initrd.txt> for details.
506 If RAM disk support (BLK_DEV_RAM) is also included, this
507 also enables initial RAM disk (initrd) support and adds
508 15 Kbytes (more on some other architectures) to the kernel size.
518 config CC_OPTIMIZE_FOR_SIZE
519 bool "Optimize for size"
522 Enabling this option will pass "-Os" instead of "-O2" to gcc
523 resulting in a smaller kernel.
531 bool "Configure standard kernel features (for small systems)"
533 This option allows certain base kernel options and settings
534 to be disabled or tweaked. This is for specialized
535 environments which can tolerate a "non-standard" kernel.
536 Only use this if you really know what you are doing.
539 bool "Enable 16-bit UID system calls" if EMBEDDED
540 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
543 This enables the legacy 16-bit UID syscall wrappers.
545 config SYSCTL_SYSCALL
546 bool "Sysctl syscall support" if EMBEDDED
550 sys_sysctl uses binary paths that have been found challenging
551 to properly maintain and use. The interface in /proc/sys
552 using paths with ascii names is now the primary path to this
555 Almost nothing using the binary sysctl interface so if you are
556 trying to save some space it is probably safe to disable this,
557 making your kernel marginally smaller.
559 If unsure say Y here.
562 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
565 Say Y here to let the kernel print out symbolic crash information and
566 symbolic stack backtraces. This increases the size of the kernel
567 somewhat, as all symbols have to be loaded into the kernel image.
570 bool "Include all symbols in kallsyms"
571 depends on DEBUG_KERNEL && KALLSYMS
573 Normally kallsyms only contains the symbols of functions, for nicer
574 OOPS messages. Some debuggers can use kallsyms for other
575 symbols too: say Y here to include all symbols, if you need them
576 and you don't care about adding 300k to the size of your kernel.
580 config KALLSYMS_EXTRA_PASS
581 bool "Do an extra kallsyms pass"
584 If kallsyms is not working correctly, the build will fail with
585 inconsistent kallsyms data. If that occurs, log a bug report and
586 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
587 Always say N here unless you find a bug in kallsyms, which must be
588 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
589 you wait for kallsyms to be fixed.
593 bool "Support for hot-pluggable devices" if EMBEDDED
596 This option is provided for the case where no hotplug or uevent
597 capabilities is wanted by the kernel. You should only consider
598 disabling this option for embedded systems that do not use modules, a
599 dynamic /dev tree, or dynamic device discovery. Just say Y.
603 bool "Enable support for printk" if EMBEDDED
605 This option enables normal printk support. Removing it
606 eliminates most of the message strings from the kernel image
607 and makes the kernel more or less silent. As this makes it
608 very difficult to diagnose system problems, saying N here is
609 strongly discouraged.
612 bool "BUG() support" if EMBEDDED
615 Disabling this option eliminates support for BUG and WARN, reducing
616 the size of your kernel image and potentially quietly ignoring
617 numerous fatal conditions. You should only consider disabling this
618 option for embedded systems with no facilities for reporting errors.
623 bool "Enable ELF core dumps" if EMBEDDED
625 Enable support for generating core dumps. Disabling saves about 4k.
627 config PCSPKR_PLATFORM
628 bool "Enable PC-Speaker support" if EMBEDDED
629 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
632 This option allows to disable the internal PC-Speaker
633 support, saving some memory.
636 bool "Disable heap randomization"
639 Randomizing heap placement makes heap exploits harder, but it
640 also breaks ancient binaries (including anything libc5 based).
641 This option changes the bootup default to heap randomization
642 disabled, and can be overriden runtime by setting
643 /proc/sys/kernel/randomize_va_space to 2.
645 On non-ancient distros (post-2000 ones) N is usually a safe choice.
649 bool "Enable full-sized data structures for core" if EMBEDDED
651 Disabling this option reduces the size of miscellaneous core
652 kernel data structures. This saves memory on small machines,
653 but may reduce performance.
656 bool "Enable futex support" if EMBEDDED
660 Disabling this option will cause the kernel to be built without
661 support for "fast userspace mutexes". The resulting kernel may not
662 run glibc-based applications correctly.
668 bool "Enable eventpoll support" if EMBEDDED
672 Disabling this option will cause the kernel to be built without
673 support for epoll family of system calls.
676 bool "Enable signalfd() system call" if EMBEDDED
680 Enable the signalfd() system call that allows to receive signals
681 on a file descriptor.
686 bool "Enable timerfd() system call" if EMBEDDED
690 Enable the timerfd() system call that allows to receive timer
691 events on a file descriptor.
696 bool "Enable eventfd() system call" if EMBEDDED
700 Enable the eventfd() system call that allows to receive both
701 kernel notification (ie. KAIO) or userspace notifications.
706 bool "Use full shmem filesystem" if EMBEDDED
710 The shmem is an internal filesystem used to manage shared memory.
711 It is backed by swap and manages resource limits. It is also exported
712 to userspace as tmpfs if TMPFS is enabled. Disabling this
713 option replaces shmem and tmpfs with the much simpler ramfs code,
714 which may be appropriate on small systems without swap.
717 bool "Enable AIO support" if EMBEDDED
720 This option enables POSIX asynchronous I/O which may by used
721 by some high performance threaded applications. Disabling
722 this option saves about 7k.
724 config VM_EVENT_COUNTERS
726 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
728 VM event counters are needed for event counts to be shown.
729 This option allows the disabling of the VM event counters
730 on EMBEDDED systems. /proc/vmstat will only show page counts
731 if VM event counters are disabled.
735 bool "Enable SLUB debugging support" if EMBEDDED
736 depends on SLUB && SYSFS
738 SLUB has extensive debug support features. Disabling these can
739 result in significant savings in code size. This also disables
740 SLUB sysfs support. /sys/slab will not exist and there will be
741 no support for cache validation etc.
744 prompt "Choose SLAB allocator"
747 This option allows to select a slab allocator.
752 The regular slab allocator that is established and known to work
753 well in all environments. It organizes cache hot objects in
754 per cpu and per node queues. SLAB is the default choice for
758 bool "SLUB (Unqueued Allocator)"
760 SLUB is a slab allocator that minimizes cache line usage
761 instead of managing queues of cached objects (SLAB approach).
762 Per cpu caching is realized using slabs of objects instead
763 of queues of objects. SLUB can use memory efficiently
764 and has enhanced diagnostics.
768 bool "SLOB (Simple Allocator)"
770 SLOB replaces the stock allocator with a drastically simpler
771 allocator. SLOB is generally more space efficient but
772 does not perform as well on large systems.
777 bool "Profiling support (EXPERIMENTAL)"
779 Say Y here to enable the extended profiling support mechanisms used
780 by profilers such as OProfile.
783 bool "Activate markers"
785 Place an empty function call at each marker site. Can be
786 dynamically changed for a probe function.
788 source "arch/Kconfig"
790 endmenu # General setup
792 config HAVE_GENERIC_DMA_COHERENT
799 depends on SLAB || SLUB_DEBUG
812 default 0 if BASE_FULL
813 default 1 if !BASE_FULL
816 bool "Enable loadable module support"
818 Kernel modules are small pieces of compiled code which can
819 be inserted in the running kernel, rather than being
820 permanently built into the kernel. You use the "modprobe"
821 tool to add (and sometimes remove) them. If you say Y here,
822 many parts of the kernel can be built as modules (by
823 answering M instead of Y where indicated): this is most
824 useful for infrequently used options which are not required
825 for booting. For more information, see the man pages for
826 modprobe, lsmod, modinfo, insmod and rmmod.
828 If you say Y here, you will need to run "make
829 modules_install" to put the modules under /lib/modules/
830 where modprobe can find them (you may need to be root to do
837 config MODULE_FORCE_LOAD
838 bool "Forced module loading"
841 Allow loading of modules without version information (ie. modprobe
842 --force). Forced module loading sets the 'F' (forced) taint flag and
843 is usually a really bad idea.
846 bool "Module unloading"
848 Without this option you will not be able to unload any
849 modules (note that some modules may not be unloadable
850 anyway), which makes your kernel smaller, faster
851 and simpler. If unsure, say Y.
853 config MODULE_FORCE_UNLOAD
854 bool "Forced module unloading"
855 depends on MODULE_UNLOAD && EXPERIMENTAL
857 This option allows you to force a module to unload, even if the
858 kernel believes it is unsafe: the kernel will remove the module
859 without waiting for anyone to stop using it (using the -f option to
860 rmmod). This is mainly for kernel developers and desperate users.
864 bool "Module versioning support"
866 Usually, you have to use modules compiled with your kernel.
867 Saying Y here makes it sometimes possible to use modules
868 compiled for different kernels, by adding enough information
869 to the modules to (hopefully) spot any changes which would
870 make them incompatible with the kernel you are running. If
873 config MODULE_SRCVERSION_ALL
874 bool "Source checksum for all modules"
876 Modules which contain a MODULE_VERSION get an extra "srcversion"
877 field inserted into their modinfo section, which contains a
878 sum of the source files which made it. This helps maintainers
879 see exactly which source was used to build a module (since
880 others sometimes change the module source without updating
881 the version). With this option, such a "srcversion" field
882 will be created for all modules. If unsure, say N.
887 This is being removed soon. These days, CONFIG_MODULES
888 implies CONFIG_KMOD, so use that instead.
895 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
897 Need stop_machine() primitive.
899 source "block/Kconfig"
901 config PREEMPT_NOTIFIERS
905 def_bool !PREEMPT_RCU
907 This option selects the classic RCU implementation that is
908 designed for best read-side performance on non-realtime
909 systems. Classic RCU is the default. Note that the
910 PREEMPT_RCU symbol is used to select/deselect this option.
projects / linux-2.6 / blob