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25 drivers that have been replaced by something else, and/or are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.
80 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
81 you'll need to say Y here.
83 You can find documentation about IPC with "info ipc" and also in
84 section 6.4 of the Linux Programmer's Guide, available from
85 <http://www.tldp.org/guides.html>.
88 bool "POSIX Message Queues"
89 depends on NET && EXPERIMENTAL
91 POSIX variant of message queues is a part of IPC. In POSIX message
92 queues every message has a priority which decides about succession
93 of receiving it by a process. If you want to compile and run
94 programs written e.g. for Solaris with use of its POSIX message
95 queues (functions mq_*) say Y here. To use this feature you will
96 also need mqueue library, available from
97 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
99 POSIX message queues are visible as a filesystem called 'mqueue'
100 and can be mounted somewhere if you want to do filesystem
101 operations on message queues.
105 config BSD_PROCESS_ACCT
106 bool "BSD Process Accounting"
108 If you say Y here, a user level program will be able to instruct the
109 kernel (via a special system call) to write process accounting
110 information to a file: whenever a process exits, information about
111 that process will be appended to the file by the kernel. The
112 information includes things such as creation time, owning user,
113 command name, memory usage, controlling terminal etc. (the complete
114 list is in the struct acct in <file:include/linux/acct.h>). It is
115 up to the user level program to do useful things with this
116 information. This is generally a good idea, so say Y.
118 config BSD_PROCESS_ACCT_V3
119 bool "BSD Process Accounting version 3 file format"
120 depends on BSD_PROCESS_ACCT
123 If you say Y here, the process accounting information is written
124 in a new file format that also logs the process IDs of each
125 process and it's parent. Note that this file format is incompatible
126 with previous v0/v1/v2 file formats, so you will need updated tools
127 for processing it. A preliminary version of these tools is available
128 at <http://http://www.de.kernel.org/pub/linux/utils/acct/>.
130 menu "Class Based Kernel Resource Management"
133 bool "Class Based Kernel Resource Management Core"
134 depends on EXPERIMENTAL
136 Class-based Kernel Resource Management is a framework for controlling
137 and monitoring resource allocation of user-defined groups of tasks or
138 incoming socket connections. For more information, please visit
141 If you say Y here, enable the Resource Class File System and atleast
142 one of the resource controllers below. Say N if you are unsure.
145 tristate "Resource Class File System (User API)"
148 RCFS is the filesystem API for CKRM. This separate configuration
149 option is provided only for debugging and will eventually disappear
150 since rcfs will be automounted whenever CKRM is configured.
152 Say N if unsure, Y if you've enabled CKRM, M to debug rcfs
155 config CKRM_TYPE_TASKCLASS
156 bool "Class Manager for Task Groups"
159 TASKCLASS provides the extensions for CKRM to track task classes
160 This is the base to enable task class based resource control for
161 cpu, memory and disk I/O.
165 config CKRM_RES_NUMTASKS
166 tristate "Number of Tasks Resource Manager"
167 depends on CKRM_TYPE_TASKCLASS
170 Provides a Resource Controller for CKRM that allows limiting no of
171 tasks a task class can have.
173 Say N if unsure, Y to use the feature.
175 config CKRM_CPU_SCHEDULE
176 bool "CKRM CPU scheduler"
177 depends on CKRM_TYPE_TASKCLASS
180 Use CKRM CPU scheduler instead of Linux Scheduler
182 Say N if unsure, Y to use the feature.
184 config CKRM_RES_BLKIO
185 tristate " Disk I/O Resource Controller"
186 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
189 Provides a resource controller for best-effort block I/O
190 bandwidth control. The controller attempts this by proportional
191 servicing of requests in the I/O scheduler. However, seek
192 optimizations and reordering by device drivers/disk controllers may
193 alter the actual bandwidth delivered to a class.
195 Say N if unsure, Y to use the feature.
198 bool "Class based physical memory controller"
202 Provide the basic support for collecting physical memory usage information
203 among classes. Say Y if you want to know the memory usage of each class.
205 config CKRM_MEM_LRUORDER_CHANGE
206 bool "Change the LRU ordering of scanned pages"
208 depends on CKRM_RES_MEM
210 While trying to free pages, by default(n), scanned pages are left were they
211 are found if they belong to relatively under-used class. In this case the
212 LRU ordering of the memory subsystemis left intact. If this option is chosen,
213 then the scanned pages are moved to the tail of the list(active or inactive).
214 Changing this to yes reduces the checking overhead but violates the approximate
215 LRU order that is maintained by the paging subsystem.
217 config CKRM_CPU_SCHEDULE_AT_BOOT
218 bool "Turn on at boot time"
219 depends on CKRM_CPU_SCHEDULE
222 Enable CKRM CPU Scheduler at boot time. Otherwise
223 it can be turned on dynamically at runtime. If not
224 turned on the default Linux Scheduler behavior
227 Say N if unsure, Y to use this feature
229 config CKRM_TYPE_SOCKETCLASS
230 bool "Class Manager for socket groups"
233 SOCKET provides the extensions for CKRM to track per socket
234 classes. This is the base to enable socket based resource
235 control for inbound connection control, bandwidth control etc.
239 config CKRM_RES_LISTENAQ
240 tristate "Multiple Accept Queues Resource Manager"
241 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
244 Provides a resource controller for CKRM to prioritize inbound
245 connection requests. See inbound control description for
246 "IP: TCP Multiple accept queues support". If you choose that
247 option choose this option to control the queue weights.
252 tristate "Vanilla Rule-based Classification Engine (RBCE)"
253 depends on CKRM && RCFS_FS
256 Provides an optional module to support creation of rules for automatic
257 classification of kernel objects. Rules are created/deleted/modified
258 through an rcfs interface. RBCE is not required for CKRM.
263 tristate "Enhanced Rule-based Classification Engine (RBCE)"
264 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
267 Provides an optional module to support creation of rules for automatic
268 classification of kernel objects, just like RBCE above. In addition,
269 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
270 enabled) and makes information on significant kernel events available
271 to userspace tools through relayfs (requires RELAYFS_FS configured).
278 bool "Sysctl support"
280 The sysctl interface provides a means of dynamically changing
281 certain kernel parameters and variables on the fly without requiring
282 a recompile of the kernel or reboot of the system. The primary
283 interface consists of a system call, but if you say Y to "/proc
284 file system support", a tree of modifiable sysctl entries will be
285 generated beneath the /proc/sys directory. They are explained in the
286 files in <file:Documentation/sysctl/>. Note that enabling this
287 option will enlarge the kernel by at least 8 KB.
289 As it is generally a good thing, you should say Y here unless
290 building a kernel for install/rescue disks or your system is very
294 bool "Auditing support"
295 default y if SECURITY_SELINUX
298 Enable auditing infrastructure that can be used with another
299 kernel subsystem, such as SELinux (which requires this for
300 logging of avc messages output). Does not do system-call
301 auditing without CONFIG_AUDITSYSCALL.
304 bool "Enable system-call auditing support"
305 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
306 default y if SECURITY_SELINUX
309 Enable low-overhead system-call auditing infrastructure that
310 can be used independently or with another kernel subsystem,
314 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
316 default 17 if ARCH_S390
317 default 16 if X86_NUMAQ || IA64
321 Select kernel log buffer size as a power of 2.
322 Defaults and Examples:
323 17 => 128 KB for S/390
324 16 => 64 KB for x86 NUMAQ or IA-64
326 14 => 16 KB for uniprocessor
331 bool "Support for hot-pluggable devices" if !ARCH_S390
334 Say Y here if you want to plug devices into your computer while
335 the system is running, and be able to use them quickly. In many
336 cases, the devices can likewise be unplugged at any time too.
338 One well known example of this is PCMCIA- or PC-cards, credit-card
339 size devices such as network cards, modems or hard drives which are
340 plugged into slots found on all modern laptop computers. Another
341 example, used on modern desktops as well as laptops, is USB.
343 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
344 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
345 Then your kernel will automatically call out to a user mode "policy
346 agent" (/sbin/hotplug) to load modules and set up software needed
347 to use devices as you hotplug them.
350 bool "Kernel .config support"
352 This option enables the complete Linux kernel ".config" file
353 contents to be saved in the kernel. It provides documentation
354 of which kernel options are used in a running kernel or in an
355 on-disk kernel. This information can be extracted from the kernel
356 image file with the script scripts/extract-ikconfig and used as
357 input to rebuild the current kernel or to build another kernel.
358 It can also be extracted from a running kernel by reading
359 /proc/config.gz if enabled (below).
362 bool "Enable access to .config through /proc/config.gz"
363 depends on IKCONFIG && PROC_FS
365 This option enables access to the kernel configuration file
366 through /proc/config.gz.
372 This option enables panic() to be called when a system is out of
373 memory. This feature along with /proc/sys/kernel/panic allows a
374 different behavior on out-of-memory conditions when the standard
375 behavior (killing processes in an attempt to recover) does not
382 depends on !OOM_PANIC
386 bool "Configure standard kernel features (for small systems)"
388 This option allows certain base kernel options and settings
389 to be disabled or tweaked. This is for specialized
390 environments which can tolerate a "non-standard" kernel.
391 Only use this if you really know what you are doing.
394 bool "Enable delay accounting (EXPERIMENTAL)"
396 In addition to counting frequency the total delay in ns is also
397 recorded. CPU delays are specified as cpu-wait and cpu-run.
398 I/O delays are recorded for memory and regular I/O.
399 Information is accessible through /proc/<pid>/delay.
403 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
406 Say Y here to let the kernel print out symbolic crash information and
407 symbolic stack backtraces. This increases the size of the kernel
408 somewhat, as all symbols have to be loaded into the kernel image.
411 bool "Include all symbols in kallsyms"
412 depends on DEBUG_KERNEL && KALLSYMS
414 Normally kallsyms only contains the symbols of functions, for nicer
415 OOPS messages. Some debuggers can use kallsyms for other
416 symbols too: say Y here to include all symbols, and you
417 don't care about adding 300k to the size of your kernel.
421 config KALLSYMS_EXTRA_PASS
422 bool "Do an extra kallsyms pass"
425 If kallsyms is not working correctly, the build will fail with
426 inconsistent kallsyms data. If that occurs, log a bug report and
427 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
428 Always say N here unless you find a bug in kallsyms, which must be
429 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
430 you wait for kallsyms to be fixed.
433 bool "Enable futex support" if EMBEDDED
436 Disabling this option will cause the kernel to be built without
437 support for "fast userspace mutexes". The resulting kernel may not
438 run glibc-based applications correctly.
441 bool "Enable eventpoll support" if EMBEDDED
444 Disabling this option will cause the kernel to be built without
445 support for epoll family of system calls.
447 source "drivers/block/Kconfig.iosched"
449 config CC_OPTIMIZE_FOR_SIZE
450 bool "Optimize for size"
451 default y if ARM || H8300
454 Enabling this option will pass "-Os" instead of "-O2" to gcc
455 resulting in a smaller kernel.
457 WARNING: some versions of gcc may generate incorrect code with this
458 option. If problems are observed, a gcc upgrade may be needed.
462 endmenu # General setup
465 menu "Loadable module support"
468 bool "Enable loadable module support"
470 Kernel modules are small pieces of compiled code which can
471 be inserted in the running kernel, rather than being
472 permanently built into the kernel. You use the "modprobe"
473 tool to add (and sometimes remove) them. If you say Y here,
474 many parts of the kernel can be built as modules (by
475 answering M instead of Y where indicated): this is most
476 useful for infrequently used options which are not required
477 for booting. For more information, see the man pages for
478 modprobe, lsmod, modinfo, insmod and rmmod.
480 If you say Y here, you will need to run "make
481 modules_install" to put the modules under /lib/modules/
482 where modprobe can find them (you may need to be root to do
488 bool "Module unloading"
491 Without this option you will not be able to unload any
492 modules (note that some modules may not be unloadable
493 anyway), which makes your kernel slightly smaller and
494 simpler. If unsure, say Y.
496 config MODULE_FORCE_UNLOAD
497 bool "Forced module unloading"
498 depends on MODULE_UNLOAD && EXPERIMENTAL
500 This option allows you to force a module to unload, even if the
501 kernel believes it is unsafe: the kernel will remove the module
502 without waiting for anyone to stop using it (using the -f option to
503 rmmod). This is mainly for kernel developers and desperate users.
506 config OBSOLETE_MODPARM
511 You need this option to use module parameters on modules which
512 have not been converted to the new module parameter system yet.
516 bool "Module versioning support (EXPERIMENTAL)"
517 depends on MODULES && EXPERIMENTAL
519 Usually, you have to use modules compiled with your kernel.
520 Saying Y here makes it sometimes possible to use modules
521 compiled for different kernels, by adding enough information
522 to the modules to (hopefully) spot any changes which would
523 make them incompatible with the kernel you are running. If
527 bool "Module signature verification (EXPERIMENTAL)"
528 depends on MODULES && EXPERIMENTAL
530 select CRYPTO_SIGNATURE
532 Check modules for valid signatures upon load.
534 config MODULE_SIG_FORCE
535 bool "Required modules to be validly signed (EXPERIMENTAL)"
536 depends on MODULE_SIG
538 Reject unsigned modules or signed modules for which we don't have a
542 bool "Automatic kernel module loading"
545 Normally when you have selected some parts of the kernel to
546 be created as kernel modules, you must load them (using the
547 "modprobe" command) before you can use them. If you say Y
548 here, some parts of the kernel will be able to load modules
549 automatically: when a part of the kernel needs a module, it
550 runs modprobe with the appropriate arguments, thereby
551 loading the module if it is available. If unsure, say Y.
556 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
558 Need stop_machine() primitive.