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25 drivers that have been replaced by something else, and/or are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.
171 config CKRM_RES_BLKIO
172 tristate " Disk I/O Resource Controller"
173 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
176 Provides a resource controller for best-effort block I/O
177 bandwidth control. The controller attempts this by proportional
178 servicing of requests in the I/O scheduler. However, seek
179 optimizations and reordering by device drivers/disk controllers may
180 alter the actual bandwidth delivered to a class.
182 Say N if unsure, Y to use the feature.
184 config CKRM_TYPE_SOCKETCLASS
185 bool "Class Manager for socket groups"
188 SOCKET provides the extensions for CKRM to track per socket
189 classes. This is the base to enable socket based resource
190 control for inbound connection control, bandwidth control etc.
194 config CKRM_RES_LISTENAQ
195 tristate "Multiple Accept Queues Resource Manager"
196 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
199 Provides a resource controller for CKRM to prioritize inbound
200 connection requests. See inbound control description for
201 "IP: TCP Multiple accept queues support". If you choose that
202 option choose this option to control the queue weights.
207 tristate "Vanilla Rule-based Classification Engine (RBCE)"
208 depends on CKRM && RCFS_FS
211 Provides an optional module to support creation of rules for automatic
212 classification of kernel objects. Rules are created/deleted/modified
213 through an rcfs interface. RBCE is not required for CKRM.
218 tristate "Enhanced Rule-based Classification Engine (RBCE)"
219 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
222 Provides an optional module to support creation of rules for automatic
223 classification of kernel objects, just like RBCE above. In addition,
224 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
225 enabled) and makes information on significant kernel events available
226 to userspace tools through relayfs (requires RELAYFS_FS configured).
233 bool "Sysctl support"
235 The sysctl interface provides a means of dynamically changing
236 certain kernel parameters and variables on the fly without requiring
237 a recompile of the kernel or reboot of the system. The primary
238 interface consists of a system call, but if you say Y to "/proc
239 file system support", a tree of modifiable sysctl entries will be
240 generated beneath the /proc/sys directory. They are explained in the
241 files in <file:Documentation/sysctl/>. Note that enabling this
242 option will enlarge the kernel by at least 8 KB.
244 As it is generally a good thing, you should say Y here unless
245 building a kernel for install/rescue disks or your system is very
249 bool "Auditing support"
250 default y if SECURITY_SELINUX
253 Enable auditing infrastructure that can be used with another
254 kernel subsystem, such as SELinux (which requires this for
255 logging of avc messages output). Does not do system-call
256 auditing without CONFIG_AUDITSYSCALL.
259 bool "Enable system-call auditing support"
260 depends on AUDIT && (X86 || PPC64 || ARCH_S390)
261 default y if SECURITY_SELINUX
264 Enable low-overhead system-call auditing infrastructure that
265 can be used independently or with another kernel subsystem,
269 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
271 default 17 if ARCH_S390
272 default 16 if X86_NUMAQ || IA64
276 Select kernel log buffer size as a power of 2.
277 Defaults and Examples:
278 17 => 128 KB for S/390
279 16 => 64 KB for x86 NUMAQ or IA-64
281 14 => 16 KB for uniprocessor
286 bool "Support for hot-pluggable devices" if !ARCH_S390
289 Say Y here if you want to plug devices into your computer while
290 the system is running, and be able to use them quickly. In many
291 cases, the devices can likewise be unplugged at any time too.
293 One well known example of this is PCMCIA- or PC-cards, credit-card
294 size devices such as network cards, modems or hard drives which are
295 plugged into slots found on all modern laptop computers. Another
296 example, used on modern desktops as well as laptops, is USB.
298 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
299 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
300 Then your kernel will automatically call out to a user mode "policy
301 agent" (/sbin/hotplug) to load modules and set up software needed
302 to use devices as you hotplug them.
305 bool "Kernel .config support"
307 This option enables the complete Linux kernel ".config" file
308 contents, information on compiler used to build the kernel,
309 kernel running when this kernel was built and kernel version
310 from Makefile to be saved in the kernel. It provides documentation
311 of which kernel options are used in a running kernel or in an
312 on-disk kernel. This information can be extracted from the kernel
313 image file with the script scripts/extract-ikconfig and used as
314 input to rebuild the current kernel or to build another kernel.
315 It can also be extracted from a running kernel by reading
316 /proc/config.gz and /proc/config_built_with, if enabled (below).
317 /proc/config.gz will list the configuration that was used
318 to build the kernel and /proc/config_built_with will list
319 information on the compiler and host machine that was used to
323 bool "Enable access to .config through /proc/config.gz"
324 depends on IKCONFIG && PROC_FS
326 This option enables access to kernel configuration file and build
327 information through /proc/config.gz.
331 bool "Configure standard kernel features (for small systems)"
333 This option allows certain base kernel options and settings
334 to be disabled or tweaked. This is for specialized
335 environments which can tolerate a "non-standard" kernel.
336 Only use this if you really know what you are doing.
339 bool "Enable delay accounting (EXPERIMENTAL)"
341 In addition to counting frequency the total delay in ns is also
342 recorded. CPU delays are specified as cpu-wait and cpu-run.
343 I/O delays are recorded for memory and regular I/O.
344 Information is accessible through /proc/<pid>/delay.
348 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
351 Say Y here to let the kernel print out symbolic crash information and
352 symbolic stack backtraces. This increases the size of the kernel
353 somewhat, as all symbols have to be loaded into the kernel image.
356 bool "Include all symbols in kallsyms"
357 depends on DEBUG_KERNEL && KALLSYMS
359 Normally kallsyms only contains the symbols of functions, for nicer
360 OOPS messages. Some debuggers can use kallsyms for other
361 symbols too: say Y here to include all symbols, and you
362 don't care about adding 300k to the size of your kernel.
367 bool "Enable futex support" if EMBEDDED
370 Disabling this option will cause the kernel to be built without
371 support for "fast userspace mutexes". The resulting kernel may not
372 run glibc-based applications correctly.
375 bool "Enable eventpoll support" if EMBEDDED
378 Disabling this option will cause the kernel to be built without
379 support for epoll family of system calls.
381 source "drivers/block/Kconfig.iosched"
383 config CC_OPTIMIZE_FOR_SIZE
384 bool "Optimize for size" if EMBEDDED
385 default y if ARM || H8300
388 Enabling this option will pass "-Os" instead of "-O2" to gcc
389 resulting in a smaller kernel.
391 WARNING: some versions of gcc may generate incorrect code with this
392 option. If problems are observed, a gcc upgrade may be needed.
396 endmenu # General setup
399 menu "Loadable module support"
402 bool "Enable loadable module support"
404 Kernel modules are small pieces of compiled code which can
405 be inserted in the running kernel, rather than being
406 permanently built into the kernel. You use the "modprobe"
407 tool to add (and sometimes remove) them. If you say Y here,
408 many parts of the kernel can be built as modules (by
409 answering M instead of Y where indicated): this is most
410 useful for infrequently used options which are not required
411 for booting. For more information, see the man pages for
412 modprobe, lsmod, modinfo, insmod and rmmod.
414 If you say Y here, you will need to run "make
415 modules_install" to put the modules under /lib/modules/
416 where modprobe can find them (you may need to be root to do
422 bool "Module unloading"
425 Without this option you will not be able to unload any
426 modules (note that some modules may not be unloadable
427 anyway), which makes your kernel slightly smaller and
428 simpler. If unsure, say Y.
430 config MODULE_FORCE_UNLOAD
431 bool "Forced module unloading"
432 depends on MODULE_UNLOAD && EXPERIMENTAL
434 This option allows you to force a module to unload, even if the
435 kernel believes it is unsafe: the kernel will remove the module
436 without waiting for anyone to stop using it (using the -f option to
437 rmmod). This is mainly for kernel developers and desperate users.
440 config OBSOLETE_MODPARM
445 You need this option to use module parameters on modules which
446 have not been converted to the new module parameter system yet.
450 bool "Module versioning support (EXPERIMENTAL)"
451 depends on MODULES && EXPERIMENTAL
453 Usually, you have to use modules compiled with your kernel.
454 Saying Y here makes it sometimes possible to use modules
455 compiled for different kernels, by adding enough information
456 to the modules to (hopefully) spot any changes which would
457 make them incompatible with the kernel you are running. If
461 bool "Automatic kernel module loading"
464 Normally when you have selected some parts of the kernel to
465 be created as kernel modules, you must load them (using the
466 "modprobe" command) before you can use them. If you say Y
467 here, some parts of the kernel will be able to load modules
468 automatically: when a part of the kernel needs a module, it
469 runs modprobe with the appropriate arguments, thereby
470 loading the module if it is available. If unsure, say Y.
475 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
477 Need stop_machine() primitive.