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25 drivers that have been replaced by something else, and/or are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 NET && 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.
124 config BSD_PROCESS_ACCT_V3
125 bool "BSD Process Accounting version 3 file format"
126 depends on BSD_PROCESS_ACCT
129 If you say Y here, the process accounting information is written
130 in a new file format that also logs the process IDs of each
131 process and it's parent. Note that this file format is incompatible
132 with previous v0/v1/v2 file formats, so you will need updated tools
133 for processing it. A preliminary version of these tools is available
134 at <http://http://www.de.kernel.org/pub/linux/utils/acct/>.
137 bool "Sysctl support"
139 The sysctl interface provides a means of dynamically changing
140 certain kernel parameters and variables on the fly without requiring
141 a recompile of the kernel or reboot of the system. The primary
142 interface consists of a system call, but if you say Y to "/proc
143 file system support", a tree of modifiable sysctl entries will be
144 generated beneath the /proc/sys directory. They are explained in the
145 files in <file:Documentation/sysctl/>. Note that enabling this
146 option will enlarge the kernel by at least 8 KB.
148 As it is generally a good thing, you should say Y here unless
149 building a kernel for install/rescue disks or your system is very
153 bool "Auditing support"
154 default y if SECURITY_SELINUX
157 Enable auditing infrastructure that can be used with another
158 kernel subsystem, such as SELinux (which requires this for
159 logging of avc messages output). Does not do system-call
160 auditing without CONFIG_AUDITSYSCALL.
163 bool "Enable system-call auditing support"
164 depends on AUDIT && (X86 || PPC64 || ARCH_S390)
165 default y if SECURITY_SELINUX
168 Enable low-overhead system-call auditing infrastructure that
169 can be used independently or with another kernel subsystem,
173 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
175 default 17 if ARCH_S390
176 default 16 if X86_NUMAQ || IA64
180 Select kernel log buffer size as a power of 2.
181 Defaults and Examples:
182 17 => 128 KB for S/390
183 16 => 64 KB for x86 NUMAQ or IA-64
185 14 => 16 KB for uniprocessor
190 bool "Support for hot-pluggable devices" if !ARCH_S390
193 Say Y here if you want to plug devices into your computer while
194 the system is running, and be able to use them quickly. In many
195 cases, the devices can likewise be unplugged at any time too.
197 One well known example of this is PCMCIA- or PC-cards, credit-card
198 size devices such as network cards, modems or hard drives which are
199 plugged into slots found on all modern laptop computers. Another
200 example, used on modern desktops as well as laptops, is USB.
202 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
203 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
204 Then your kernel will automatically call out to a user mode "policy
205 agent" (/sbin/hotplug) to load modules and set up software needed
206 to use devices as you hotplug them.
209 bool "Kernel .config support"
211 This option enables the complete Linux kernel ".config" file
212 contents, information on compiler used to build the kernel,
213 kernel running when this kernel was built and kernel version
214 from Makefile to be saved in the kernel. It provides documentation
215 of which kernel options are used in a running kernel or in an
216 on-disk kernel. This information can be extracted from the kernel
217 image file with the script scripts/extract-ikconfig and used as
218 input to rebuild the current kernel or to build another kernel.
219 It can also be extracted from a running kernel by reading
220 /proc/config.gz and /proc/config_built_with, if enabled (below).
221 /proc/config.gz will list the configuration that was used
222 to build the kernel and /proc/config_built_with will list
223 information on the compiler and host machine that was used to
227 bool "Enable access to .config through /proc/config.gz"
228 depends on IKCONFIG && PROC_FS
230 This option enables access to kernel configuration file and build
231 information through /proc/config.gz.
235 bool "Configure standard kernel features (for small systems)"
237 This option allows certain base kernel options and settings
238 to be disabled or tweaked. This is for specialized
239 environments which can tolerate a "non-standard" kernel.
240 Only use this if you really know what you are doing.
243 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
246 Say Y here to let the kernel print out symbolic crash information and
247 symbolic stack backtraces. This increases the size of the kernel
248 somewhat, as all symbols have to be loaded into the kernel image.
251 bool "Include all symbols in kallsyms"
252 depends on DEBUG_KERNEL && KALLSYMS
254 Normally kallsyms only contains the symbols of functions, for nicer
255 OOPS messages. Some debuggers can use kallsyms for other
256 symbols too: say Y here to include all symbols, and you
257 don't care about adding 300k to the size of your kernel.
262 bool "Enable futex support" if EMBEDDED
265 Disabling this option will cause the kernel to be built without
266 support for "fast userspace mutexes". The resulting kernel may not
267 run glibc-based applications correctly.
270 bool "Enable eventpoll support" if EMBEDDED
273 Disabling this option will cause the kernel to be built without
274 support for epoll family of system calls.
276 source "drivers/block/Kconfig.iosched"
278 config CC_OPTIMIZE_FOR_SIZE
279 bool "Optimize for size"
280 default y if ARM || H8300
283 Enabling this option will pass "-Os" instead of "-O2" to gcc
284 resulting in a smaller kernel.
286 WARNING: some versions of gcc may generate incorrect code with this
287 option. If problems are observed, a gcc upgrade may be needed.
291 endmenu # General setup
294 menu "Loadable module support"
297 bool "Enable loadable module support"
299 Kernel modules are small pieces of compiled code which can
300 be inserted in the running kernel, rather than being
301 permanently built into the kernel. You use the "modprobe"
302 tool to add (and sometimes remove) them. If you say Y here,
303 many parts of the kernel can be built as modules (by
304 answering M instead of Y where indicated): this is most
305 useful for infrequently used options which are not required
306 for booting. For more information, see the man pages for
307 modprobe, lsmod, modinfo, insmod and rmmod.
309 If you say Y here, you will need to run "make
310 modules_install" to put the modules under /lib/modules/
311 where modprobe can find them (you may need to be root to do
317 bool "Module unloading"
320 Without this option you will not be able to unload any
321 modules (note that some modules may not be unloadable
322 anyway), which makes your kernel slightly smaller and
323 simpler. If unsure, say Y.
325 config MODULE_FORCE_UNLOAD
326 bool "Forced module unloading"
327 depends on MODULE_UNLOAD && EXPERIMENTAL
329 This option allows you to force a module to unload, even if the
330 kernel believes it is unsafe: the kernel will remove the module
331 without waiting for anyone to stop using it (using the -f option to
332 rmmod). This is mainly for kernel developers and desperate users.
335 config OBSOLETE_MODPARM
340 You need this option to use module parameters on modules which
341 have not been converted to the new module parameter system yet.
345 bool "Module versioning support (EXPERIMENTAL)"
346 depends on MODULES && EXPERIMENTAL
348 Usually, you have to use modules compiled with your kernel.
349 Saying Y here makes it sometimes possible to use modules
350 compiled for different kernels, by adding enough information
351 to the modules to (hopefully) spot any changes which would
352 make them incompatible with the kernel you are running. If
356 bool "Automatic kernel module loading"
359 Normally when you have selected some parts of the kernel to
360 be created as kernel modules, you must load them (using the
361 "modprobe" command) before you can use them. If you say Y
362 here, some parts of the kernel will be able to load modules
363 automatically: when a part of the kernel needs a module, it
364 runs modprobe with the appropriate arguments, thereby
365 loading the module if it is available. If unsure, say Y.
370 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
372 Need stop_machine() primitive.