2 menu "Code maturity level options"
5 bool "Prompt for development and/or incomplete code/drivers"
7 Some of the various things that Linux supports (such as network
8 drivers, file systems, network protocols, etc.) can be in a state
9 of development where the functionality, stability, or the level of
10 testing is not yet high enough for general use. This is usually
11 known as the "alpha-test" phase among developers. If a feature is
12 currently in alpha-test, then the developers usually discourage
13 uninformed widespread use of this feature by the general public to
14 avoid "Why doesn't this work?" type mail messages. However, active
15 testing and use of these systems is welcomed. Just be aware that it
16 may not meet the normal level of reliability or it may fail to work
17 in some special cases. Detailed bug reports from people familiar
18 with the kernel internals are usually welcomed by the developers
19 (before submitting bug reports, please read the documents
20 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
21 <file:Documentation/BUG-HUNTING>, and
22 <file:Documentation/oops-tracing.txt> in the kernel source).
24 This option will also make obsoleted drivers available. These are
25 drivers that have been replaced by something else, and/or are
26 scheduled to be removed in a future kernel release.
28 Unless you intend to help test and develop a feature or driver that
29 falls into this category, or you have a situation that requires
30 using these features, you should probably say N here, which will
31 cause the configurator to present you with fewer choices. If
32 you say Y here, you will be offered the choice of using features or
33 drivers that are currently considered to be in the alpha-test phase.
36 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
39 Select this option if you don't even want to see the option
40 to configure known-broken drivers.
45 bool "Select only drivers that don't need compile-time external firmware" if EXPERIMENTAL
48 Select this option if you don't have magic firmware for drivers that
55 depends on !CLEAN_COMPILE
60 depends on BROKEN || !SMP
69 bool "Support for paging of anonymous memory (swap)"
73 This option allows you to choose whether you want to have support
74 for socalled swap devices or swap files in your kernel that are
75 used to provide more virtual memory than the actual RAM present
76 in your computer. If unsure say Y.
81 Inter Process Communication is a suite of library functions and
82 system calls which let processes (running programs) synchronize and
83 exchange information. It is generally considered to be a good thing,
84 and some programs won't run unless you say Y here. In particular, if
85 you want to run the DOS emulator dosemu under Linux (read the
86 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
87 you'll need to say Y here.
89 You can find documentation about IPC with "info ipc" and also in
90 section 6.4 of the Linux Programmer's Guide, available from
91 <http://www.tldp.org/guides.html>.
94 bool "POSIX Message Queues"
95 depends on EXPERIMENTAL
97 POSIX variant of message queues is a part of IPC. In POSIX message
98 queues every message has a priority which decides about succession
99 of receiving it by a process. If you want to compile and run
100 programs written e.g. for Solaris with use of its POSIX message
101 queues (functions mq_*) say Y here. To use this feature you will
102 also need mqueue library, available from
103 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
105 POSIX message queues are visible as a filesystem called 'mqueue'
106 and can be mounted somewhere if you want to do filesystem
107 operations on message queues.
111 config BSD_PROCESS_ACCT
112 bool "BSD Process Accounting"
114 If you say Y here, a user level program will be able to instruct the
115 kernel (via a special system call) to write process accounting
116 information to a file: whenever a process exits, information about
117 that process will be appended to the file by the kernel. The
118 information includes things such as creation time, owning user,
119 command name, memory usage, controlling terminal etc. (the complete
120 list is in the struct acct in <file:include/linux/acct.h>). It is
121 up to the user level program to do useful things with this
122 information. This is generally a good idea, so say Y.
125 bool "Sysctl support"
127 The sysctl interface provides a means of dynamically changing
128 certain kernel parameters and variables on the fly without requiring
129 a recompile of the kernel or reboot of the system. The primary
130 interface consists of a system call, but if you say Y to "/proc
131 file system support", a tree of modifiable sysctl entries will be
132 generated beneath the /proc/sys directory. They are explained in the
133 files in <file:Documentation/sysctl/>. Note that enabling this
134 option will enlarge the kernel by at least 8 KB.
136 As it is generally a good thing, you should say Y here unless
137 building a kernel for install/rescue disks or your system is very
141 bool "Auditing support"
142 default y if SECURITY_SELINUX
145 Enable auditing infrastructure that can be used with another
146 kernel subsystem, such as SELinux (which requires this for
147 logging of avc messages output). Does not do system-call
148 auditing without CONFIG_AUDITSYSCALL.
151 bool "Enable system-call auditing support"
152 depends on AUDIT && (X86 || PPC64 || ARCH_S390)
153 default y if SECURITY_SELINUX
156 Enable low-overhead system-call auditing infrastructure that
157 can be used independently or with another kernel subsystem,
161 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
163 default 17 if ARCH_S390
164 default 16 if X86_NUMAQ || IA64
168 Select kernel log buffer size as a power of 2.
169 Defaults and Examples:
170 17 => 128 KB for S/390
171 16 => 64 KB for x86 NUMAQ or IA-64
173 14 => 16 KB for uniprocessor
178 bool "Support for hot-pluggable devices" if !ARCH_S390
181 Say Y here if you want to plug devices into your computer while
182 the system is running, and be able to use them quickly. In many
183 cases, the devices can likewise be unplugged at any time too.
185 One well known example of this is PCMCIA- or PC-cards, credit-card
186 size devices such as network cards, modems or hard drives which are
187 plugged into slots found on all modern laptop computers. Another
188 example, used on modern desktops as well as laptops, is USB.
190 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
191 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
192 Then your kernel will automatically call out to a user mode "policy
193 agent" (/sbin/hotplug) to load modules and set up software needed
194 to use devices as you hotplug them.
197 bool "Kernel .config support"
199 This option enables the complete Linux kernel ".config" file
200 contents, information on compiler used to build the kernel,
201 kernel running when this kernel was built and kernel version
202 from Makefile to be saved in the kernel. It provides documentation
203 of which kernel options are used in a running kernel or in an
204 on-disk kernel. This information can be extracted from the kernel
205 image file with the script scripts/extract-ikconfig and used as
206 input to rebuild the current kernel or to build another kernel.
207 It can also be extracted from a running kernel by reading
208 /proc/config.gz and /proc/config_built_with, if enabled (below).
209 /proc/config.gz will list the configuration that was used
210 to build the kernel and /proc/config_built_with will list
211 information on the compiler and host machine that was used to
215 bool "Enable access to .config through /proc/config.gz"
216 depends on IKCONFIG && PROC_FS
218 This option enables access to kernel configuration file and build
219 information through /proc/config.gz.
223 bool "Configure standard kernel features (for small systems)"
225 This option allows certain base kernel options and settings
226 to be disabled or tweaked. This is for specialized
227 environments which can tolerate a "non-standard" kernel.
228 Only use this if you really know what you are doing.
231 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
234 Say Y here to let the kernel print out symbolic crash information and
235 symbolic stack backtraces. This increases the size of the kernel
236 somewhat, as all symbols have to be loaded into the kernel image.
239 bool "Enable futex support" if EMBEDDED
242 Disabling this option will cause the kernel to be built without
243 support for "fast userspace mutexes". The resulting kernel may not
244 run glibc-based applications correctly.
247 bool "Enable eventpoll support" if EMBEDDED
250 Disabling this option will cause the kernel to be built without
251 support for epoll family of system calls.
253 source "drivers/block/Kconfig.iosched"
255 config CC_OPTIMIZE_FOR_SIZE
256 bool "Optimize for size" if EMBEDDED
257 default y if ARM || H8300
260 Enabling this option will pass "-Os" instead of "-O2" to gcc
261 resulting in a smaller kernel.
263 WARNING: some versions of gcc may generate incorrect code with this
264 option. If problems are observed, a gcc upgrade may be needed.
268 endmenu # General setup
271 menu "Loadable module support"
274 bool "Enable loadable module support"
276 Kernel modules are small pieces of compiled code which can
277 be inserted in the running kernel, rather than being
278 permanently built into the kernel. You use the "modprobe"
279 tool to add (and sometimes remove) them. If you say Y here,
280 many parts of the kernel can be built as modules (by
281 answering M instead of Y where indicated): this is most
282 useful for infrequently used options which are not required
283 for booting. For more information, see the man pages for
284 modprobe, lsmod, modinfo, insmod and rmmod.
286 If you say Y here, you will need to run "make
287 modules_install" to put the modules under /lib/modules/
288 where modprobe can find them (you may need to be root to do
294 bool "Module unloading"
297 Without this option you will not be able to unload any
298 modules (note that some modules may not be unloadable
299 anyway), which makes your kernel slightly smaller and
300 simpler. If unsure, say Y.
302 config MODULE_FORCE_UNLOAD
303 bool "Forced module unloading"
304 depends on MODULE_UNLOAD && EXPERIMENTAL
306 This option allows you to force a module to unload, even if the
307 kernel believes it is unsafe: the kernel will remove the module
308 without waiting for anyone to stop using it (using the -f option to
309 rmmod). This is mainly for kernel developers and desperate users.
312 config OBSOLETE_MODPARM
317 You need this option to use module parameters on modules which
318 have not been converted to the new module parameter system yet.
322 bool "Module versioning support (EXPERIMENTAL)"
323 depends on MODULES && EXPERIMENTAL
325 Usually, you have to use modules compiled with your kernel.
326 Saying Y here makes it sometimes possible to use modules
327 compiled for different kernels, by adding enough information
328 to the modules to (hopefully) spot any changes which would
329 make them incompatible with the kernel you are running. If
333 bool "Automatic kernel module loading"
336 Normally when you have selected some parts of the kernel to
337 be created as kernel modules, you must load them (using the
338 "modprobe" command) before you can use them. If you say Y
339 here, some parts of the kernel will be able to load modules
340 automatically: when a part of the kernel needs a module, it
341 runs modprobe with the appropriate arguments, thereby
342 loading the module if it is available. If unsure, say Y.
347 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
349 Need stop_machine() primitive.