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25 drivers that have been replaced by something else, and/or are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.
46 depends on !CLEAN_COMPILE
51 depends on BROKEN || !SMP
60 bool "Support for paging of anonymous memory (swap)"
64 This option allows you to choose whether you want to have support
65 for socalled swap devices or swap files in your kernel that are
66 used to provide more virtual memory than the actual RAM present
67 in your computer. If unsure say Y.
73 Inter Process Communication is a suite of library functions and
74 system calls which let processes (running programs) synchronize and
75 exchange information. It is generally considered to be a good thing,
76 and some programs won't run unless you say Y here. In particular, if
77 you want to run the DOS emulator dosemu under Linux (read the
78 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
79 you'll need to say Y here.
81 You can find documentation about IPC with "info ipc" and also in
82 section 6.4 of the Linux Programmer's Guide, available from
83 <http://www.tldp.org/guides.html>.
86 bool "POSIX Message Queues"
87 depends on NET && EXPERIMENTAL
89 POSIX variant of message queues is a part of IPC. In POSIX message
90 queues every message has a priority which decides about succession
91 of receiving it by a process. If you want to compile and run
92 programs written e.g. for Solaris with use of its POSIX message
93 queues (functions mq_*) say Y here. To use this feature you will
94 also need mqueue library, available from
95 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
97 POSIX message queues are visible as a filesystem called 'mqueue'
98 and can be mounted somewhere if you want to do filesystem
99 operations on message queues.
103 config BSD_PROCESS_ACCT
104 bool "BSD Process Accounting"
106 If you say Y here, a user level program will be able to instruct the
107 kernel (via a special system call) to write process accounting
108 information to a file: whenever a process exits, information about
109 that process will be appended to the file by the kernel. The
110 information includes things such as creation time, owning user,
111 command name, memory usage, controlling terminal etc. (the complete
112 list is in the struct acct in <file:include/linux/acct.h>). It is
113 up to the user level program to do useful things with this
114 information. This is generally a good idea, so say Y.
116 config BSD_PROCESS_ACCT_V3
117 bool "BSD Process Accounting version 3 file format"
118 depends on BSD_PROCESS_ACCT
121 If you say Y here, the process accounting information is written
122 in a new file format that also logs the process IDs of each
123 process and it's parent. Note that this file format is incompatible
124 with previous v0/v1/v2 file formats, so you will need updated tools
125 for processing it. A preliminary version of these tools is available
126 at <http://http://www.de.kernel.org/pub/linux/utils/acct/>.
129 bool "Sysctl support"
131 The sysctl interface provides a means of dynamically changing
132 certain kernel parameters and variables on the fly without requiring
133 a recompile of the kernel or reboot of the system. The primary
134 interface consists of a system call, but if you say Y to "/proc
135 file system support", a tree of modifiable sysctl entries will be
136 generated beneath the /proc/sys directory. They are explained in the
137 files in <file:Documentation/sysctl/>. Note that enabling this
138 option will enlarge the kernel by at least 8 KB.
140 As it is generally a good thing, you should say Y here unless
141 building a kernel for install/rescue disks or your system is very
145 bool "Auditing support"
146 default y if SECURITY_SELINUX
149 Enable auditing infrastructure that can be used with another
150 kernel subsystem, such as SELinux (which requires this for
151 logging of avc messages output). Does not do system-call
152 auditing without CONFIG_AUDITSYSCALL.
155 bool "Enable system-call auditing support"
156 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
157 default y if SECURITY_SELINUX
160 Enable low-overhead system-call auditing infrastructure that
161 can be used independently or with another kernel subsystem,
165 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
167 default 17 if ARCH_S390
168 default 16 if X86_NUMAQ || IA64
172 Select kernel log buffer size as a power of 2.
173 Defaults and Examples:
174 17 => 128 KB for S/390
175 16 => 64 KB for x86 NUMAQ or IA-64
177 14 => 16 KB for uniprocessor
182 bool "Support for hot-pluggable devices" if !ARCH_S390
185 Say Y here if you want to plug devices into your computer while
186 the system is running, and be able to use them quickly. In many
187 cases, the devices can likewise be unplugged at any time too.
189 One well known example of this is PCMCIA- or PC-cards, credit-card
190 size devices such as network cards, modems or hard drives which are
191 plugged into slots found on all modern laptop computers. Another
192 example, used on modern desktops as well as laptops, is USB.
194 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
195 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
196 Then your kernel will automatically call out to a user mode "policy
197 agent" (/sbin/hotplug) to load modules and set up software needed
198 to use devices as you hotplug them.
201 bool "Kernel .config support"
203 This option enables the complete Linux kernel ".config" file
204 contents to be saved in the kernel. It provides documentation
205 of which kernel options are used in a running kernel or in an
206 on-disk kernel. This information can be extracted from the kernel
207 image file with the script scripts/extract-ikconfig and used as
208 input to rebuild the current kernel or to build another kernel.
209 It can also be extracted from a running kernel by reading
210 /proc/config.gz if enabled (below).
213 bool "Enable access to .config through /proc/config.gz"
214 depends on IKCONFIG && PROC_FS
216 This option enables access to the kernel configuration file
217 through /proc/config.gz.
221 bool "Configure standard kernel features (for small systems)"
223 This option allows certain base kernel options and settings
224 to be disabled or tweaked. This is for specialized
225 environments which can tolerate a "non-standard" kernel.
226 Only use this if you really know what you are doing.
229 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
232 Say Y here to let the kernel print out symbolic crash information and
233 symbolic stack backtraces. This increases the size of the kernel
234 somewhat, as all symbols have to be loaded into the kernel image.
237 bool "Include all symbols in kallsyms"
238 depends on DEBUG_KERNEL && KALLSYMS
240 Normally kallsyms only contains the symbols of functions, for nicer
241 OOPS messages. Some debuggers can use kallsyms for other
242 symbols too: say Y here to include all symbols, and you
243 don't care about adding 300k to the size of your kernel.
247 config KALLSYMS_EXTRA_PASS
248 bool "Do an extra kallsyms pass"
251 If kallsyms is not working correctly, the build will fail with
252 inconsistent kallsyms data. If that occurs, log a bug report and
253 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
254 Always say N here unless you find a bug in kallsyms, which must be
255 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
256 you wait for kallsyms to be fixed.
259 bool "Enable futex support" if EMBEDDED
262 Disabling this option will cause the kernel to be built without
263 support for "fast userspace mutexes". The resulting kernel may not
264 run glibc-based applications correctly.
267 bool "Enable eventpoll support" if EMBEDDED
270 Disabling this option will cause the kernel to be built without
271 support for epoll family of system calls.
273 source "drivers/block/Kconfig.iosched"
275 config CC_OPTIMIZE_FOR_SIZE
276 bool "Optimize for size" if EMBEDDED
277 default y if ARM || H8300
280 Enabling this option will pass "-Os" instead of "-O2" to gcc
281 resulting in a smaller kernel.
283 WARNING: some versions of gcc may generate incorrect code with this
284 option. If problems are observed, a gcc upgrade may be needed.
288 endmenu # General setup
291 menu "Loadable module support"
294 bool "Enable loadable module support"
296 Kernel modules are small pieces of compiled code which can
297 be inserted in the running kernel, rather than being
298 permanently built into the kernel. You use the "modprobe"
299 tool to add (and sometimes remove) them. If you say Y here,
300 many parts of the kernel can be built as modules (by
301 answering M instead of Y where indicated): this is most
302 useful for infrequently used options which are not required
303 for booting. For more information, see the man pages for
304 modprobe, lsmod, modinfo, insmod and rmmod.
306 If you say Y here, you will need to run "make
307 modules_install" to put the modules under /lib/modules/
308 where modprobe can find them (you may need to be root to do
314 bool "Module unloading"
317 Without this option you will not be able to unload any
318 modules (note that some modules may not be unloadable
319 anyway), which makes your kernel slightly smaller and
320 simpler. If unsure, say Y.
322 config MODULE_FORCE_UNLOAD
323 bool "Forced module unloading"
324 depends on MODULE_UNLOAD && EXPERIMENTAL
326 This option allows you to force a module to unload, even if the
327 kernel believes it is unsafe: the kernel will remove the module
328 without waiting for anyone to stop using it (using the -f option to
329 rmmod). This is mainly for kernel developers and desperate users.
332 config OBSOLETE_MODPARM
337 You need this option to use module parameters on modules which
338 have not been converted to the new module parameter system yet.
342 bool "Module versioning support (EXPERIMENTAL)"
343 depends on MODULES && EXPERIMENTAL
345 Usually, you have to use modules compiled with your kernel.
346 Saying Y here makes it sometimes possible to use modules
347 compiled for different kernels, by adding enough information
348 to the modules to (hopefully) spot any changes which would
349 make them incompatible with the kernel you are running. If
353 bool "Automatic kernel module loading"
356 Normally when you have selected some parts of the kernel to
357 be created as kernel modules, you must load them (using the
358 "modprobe" command) before you can use them. If you say Y
359 here, some parts of the kernel will be able to load modules
360 automatically: when a part of the kernel needs a module, it
361 runs modprobe with the appropriate arguments, thereby
362 loading the module if it is available. If unsure, say Y.
367 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
369 Need stop_machine() primitive.