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25 drivers that have been replaced by something else, and/or are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.
88 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
89 you'll need to say Y here.
91 You can find documentation about IPC with "info ipc" and also in
92 section 6.4 of the Linux Programmer's Guide, available from
93 <http://www.tldp.org/guides.html>.
96 bool "POSIX Message Queues"
97 depends on NET && EXPERIMENTAL
99 POSIX variant of message queues is a part of IPC. In POSIX message
100 queues every message has a priority which decides about succession
101 of receiving it by a process. If you want to compile and run
102 programs written e.g. for Solaris with use of its POSIX message
103 queues (functions mq_*) say Y here. To use this feature you will
104 also need mqueue library, available from
105 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
107 POSIX message queues are visible as a filesystem called 'mqueue'
108 and can be mounted somewhere if you want to do filesystem
109 operations on message queues.
113 config BSD_PROCESS_ACCT
114 bool "BSD Process Accounting"
116 If you say Y here, a user level program will be able to instruct the
117 kernel (via a special system call) to write process accounting
118 information to a file: whenever a process exits, information about
119 that process will be appended to the file by the kernel. The
120 information includes things such as creation time, owning user,
121 command name, memory usage, controlling terminal etc. (the complete
122 list is in the struct acct in <file:include/linux/acct.h>). It is
123 up to the user level program to do useful things with this
124 information. This is generally a good idea, so say Y.
126 menu "Class Based Kernel Resource Management"
129 bool "Class Based Kernel Resource Management Core"
130 depends on EXPERIMENTAL
132 Class-based Kernel Resource Management is a framework for controlling
133 and monitoring resource allocation of user-defined groups of tasks or
134 incoming socket connections. For more information, please visit
137 If you say Y here, enable the Resource Class File System and atleast
138 one of the resource controllers below. Say N if you are unsure.
141 tristate "Resource Class File System (User API)"
144 RCFS is the filesystem API for CKRM. This separate configuration
145 option is provided only for debugging and will eventually disappear
146 since rcfs will be automounted whenever CKRM is configured.
148 Say N if unsure, Y if you've enabled CKRM, M to debug rcfs
151 config CKRM_TYPE_TASKCLASS
152 bool "Class Manager for Task Groups"
155 TASKCLASS provides the extensions for CKRM to track task classes
156 This is the base to enable task class based resource control for
157 cpu, memory and disk I/O.
161 config CKRM_RES_NUMTASKS
162 tristate "Number of Tasks Resource Manager"
163 depends on CKRM_TYPE_TASKCLASS
166 Provides a Resource Controller for CKRM that allows limiting no of
167 tasks a task class can have.
169 Say N if unsure, Y to use the feature.
172 bool "Class based physical memory controller"
176 Provide the basic support for collecting physical memory usage information
177 among classes. Say Y if you want to know the memory usage of each class.
179 config CKRM_MEM_LRUORDER_CHANGE
180 bool "Change the LRU ordering of scanned pages"
182 depends on CKRM_RES_MEM
184 While trying to free pages, by default(n), scanned pages are left were they
185 are found if they belong to relatively under-used class. In this case the
186 LRU ordering of the memory subsystemis left intact. If this option is chosen,
187 then the scanned pages are moved to the tail of the list(active or inactive).
188 Changing this to yes reduces the checking overhead but violates the approximate
189 LRU order that is maintained by the paging subsystem.
191 config CKRM_TYPE_SOCKETCLASS
192 bool "Class Manager for socket groups"
195 SOCKET provides the extensions for CKRM to track per socket
196 classes. This is the base to enable socket based resource
197 control for inbound connection control, bandwidth control etc.
201 config CKRM_RES_LISTENAQ
202 tristate "Multiple Accept Queues Resource Manager"
203 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
206 Provides a resource controller for CKRM to prioritize inbound
207 connection requests. See inbound control description for
208 "IP: TCP Multiple accept queues support". If you choose that
209 option choose this option to control the queue weights.
214 tristate "Vanilla Rule-based Classification Engine (RBCE)"
215 depends on CKRM && RCFS_FS
218 Provides an optional module to support creation of rules for automatic
219 classification of kernel objects. Rules are created/deleted/modified
220 through an rcfs interface. RBCE is not required for CKRM.
225 tristate "Enhanced Rule-based Classification Engine (RBCE)"
226 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
229 Provides an optional module to support creation of rules for automatic
230 classification of kernel objects, just like RBCE above. In addition,
231 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
232 enabled) and makes information on significant kernel events available
233 to userspace tools through relayfs (requires RELAYFS_FS configured).
240 bool "Sysctl support"
242 The sysctl interface provides a means of dynamically changing
243 certain kernel parameters and variables on the fly without requiring
244 a recompile of the kernel or reboot of the system. The primary
245 interface consists of a system call, but if you say Y to "/proc
246 file system support", a tree of modifiable sysctl entries will be
247 generated beneath the /proc/sys directory. They are explained in the
248 files in <file:Documentation/sysctl/>. Note that enabling this
249 option will enlarge the kernel by at least 8 KB.
251 As it is generally a good thing, you should say Y here unless
252 building a kernel for install/rescue disks or your system is very
256 bool "Auditing support"
257 default y if SECURITY_SELINUX
260 Enable auditing infrastructure that can be used with another
261 kernel subsystem, such as SELinux (which requires this for
262 logging of avc messages output). Does not do system-call
263 auditing without CONFIG_AUDITSYSCALL.
266 bool "Enable system-call auditing support"
267 depends on AUDIT && (X86 || PPC64 || ARCH_S390)
268 default y if SECURITY_SELINUX
271 Enable low-overhead system-call auditing infrastructure that
272 can be used independently or with another kernel subsystem,
276 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
278 default 17 if ARCH_S390
279 default 16 if X86_NUMAQ || IA64
283 Select kernel log buffer size as a power of 2.
284 Defaults and Examples:
285 17 => 128 KB for S/390
286 16 => 64 KB for x86 NUMAQ or IA-64
288 14 => 16 KB for uniprocessor
293 bool "Support for hot-pluggable devices" if !ARCH_S390
296 Say Y here if you want to plug devices into your computer while
297 the system is running, and be able to use them quickly. In many
298 cases, the devices can likewise be unplugged at any time too.
300 One well known example of this is PCMCIA- or PC-cards, credit-card
301 size devices such as network cards, modems or hard drives which are
302 plugged into slots found on all modern laptop computers. Another
303 example, used on modern desktops as well as laptops, is USB.
305 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
306 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
307 Then your kernel will automatically call out to a user mode "policy
308 agent" (/sbin/hotplug) to load modules and set up software needed
309 to use devices as you hotplug them.
312 bool "Kernel .config support"
314 This option enables the complete Linux kernel ".config" file
315 contents, information on compiler used to build the kernel,
316 kernel running when this kernel was built and kernel version
317 from Makefile to be saved in the kernel. It provides documentation
318 of which kernel options are used in a running kernel or in an
319 on-disk kernel. This information can be extracted from the kernel
320 image file with the script scripts/extract-ikconfig and used as
321 input to rebuild the current kernel or to build another kernel.
322 It can also be extracted from a running kernel by reading
323 /proc/config.gz and /proc/config_built_with, if enabled (below).
324 /proc/config.gz will list the configuration that was used
325 to build the kernel and /proc/config_built_with will list
326 information on the compiler and host machine that was used to
330 bool "Enable access to .config through /proc/config.gz"
331 depends on IKCONFIG && PROC_FS
333 This option enables access to kernel configuration file and build
334 information through /proc/config.gz.
338 bool "Configure standard kernel features (for small systems)"
340 This option allows certain base kernel options and settings
341 to be disabled or tweaked. This is for specialized
342 environments which can tolerate a "non-standard" kernel.
343 Only use this if you really know what you are doing.
346 bool "Enable delay accounting (EXPERIMENTAL)"
348 In addition to counting frequency the total delay in ns is also
349 recorded. CPU delays are specified as cpu-wait and cpu-run.
350 I/O delays are recorded for memory and regular I/O.
351 Information is accessible through /proc/<pid>/delay.
355 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
358 Say Y here to let the kernel print out symbolic crash information and
359 symbolic stack backtraces. This increases the size of the kernel
360 somewhat, as all symbols have to be loaded into the kernel image.
363 bool "Include all symbols in kallsyms"
364 depends on DEBUG_KERNEL && KALLSYMS
366 Normally kallsyms only contains the symbols of functions, for nicer
367 OOPS messages. Some debuggers can use kallsyms for other
368 symbols too: say Y here to include all symbols, and you
369 don't care about adding 300k to the size of your kernel.
374 bool "Enable futex support" if EMBEDDED
377 Disabling this option will cause the kernel to be built without
378 support for "fast userspace mutexes". The resulting kernel may not
379 run glibc-based applications correctly.
382 bool "Enable eventpoll support" if EMBEDDED
385 Disabling this option will cause the kernel to be built without
386 support for epoll family of system calls.
388 source "drivers/block/Kconfig.iosched"
390 config CC_OPTIMIZE_FOR_SIZE
391 bool "Optimize for size" if EMBEDDED
392 default y if ARM || H8300
395 Enabling this option will pass "-Os" instead of "-O2" to gcc
396 resulting in a smaller kernel.
398 WARNING: some versions of gcc may generate incorrect code with this
399 option. If problems are observed, a gcc upgrade may be needed.
403 endmenu # General setup
406 menu "Loadable module support"
409 bool "Enable loadable module support"
411 Kernel modules are small pieces of compiled code which can
412 be inserted in the running kernel, rather than being
413 permanently built into the kernel. You use the "modprobe"
414 tool to add (and sometimes remove) them. If you say Y here,
415 many parts of the kernel can be built as modules (by
416 answering M instead of Y where indicated): this is most
417 useful for infrequently used options which are not required
418 for booting. For more information, see the man pages for
419 modprobe, lsmod, modinfo, insmod and rmmod.
421 If you say Y here, you will need to run "make
422 modules_install" to put the modules under /lib/modules/
423 where modprobe can find them (you may need to be root to do
429 bool "Module unloading"
432 Without this option you will not be able to unload any
433 modules (note that some modules may not be unloadable
434 anyway), which makes your kernel slightly smaller and
435 simpler. If unsure, say Y.
437 config MODULE_FORCE_UNLOAD
438 bool "Forced module unloading"
439 depends on MODULE_UNLOAD && EXPERIMENTAL
441 This option allows you to force a module to unload, even if the
442 kernel believes it is unsafe: the kernel will remove the module
443 without waiting for anyone to stop using it (using the -f option to
444 rmmod). This is mainly for kernel developers and desperate users.
447 config OBSOLETE_MODPARM
452 You need this option to use module parameters on modules which
453 have not been converted to the new module parameter system yet.
457 bool "Module versioning support (EXPERIMENTAL)"
458 depends on MODULES && EXPERIMENTAL
460 Usually, you have to use modules compiled with your kernel.
461 Saying Y here makes it sometimes possible to use modules
462 compiled for different kernels, by adding enough information
463 to the modules to (hopefully) spot any changes which would
464 make them incompatible with the kernel you are running. If
468 bool "Automatic kernel module loading"
471 Normally when you have selected some parts of the kernel to
472 be created as kernel modules, you must load them (using the
473 "modprobe" command) before you can use them. If you say Y
474 here, some parts of the kernel will be able to load modules
475 automatically: when a part of the kernel needs a module, it
476 runs modprobe with the appropriate arguments, thereby
477 loading the module if it is available. If unsure, say Y.
482 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
484 Need stop_machine() primitive.