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25 drivers that have been replaced by something else, and/or are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_CPU_MONITOR
185 bool "CKRM CPU Resoure Monitor"
186 depends on CKRM_CPU_SCHEDULE
189 Monitor CPU Resource Usage of the classes
191 Say N if unsure, Y to use the feature.
193 config CKRM_RES_BLKIO
194 tristate " Disk I/O Resource Controller"
195 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
198 Provides a resource controller for best-effort block I/O
199 bandwidth control. The controller attempts this by proportional
200 servicing of requests in the I/O scheduler. However, seek
201 optimizations and reordering by device drivers/disk controllers may
202 alter the actual bandwidth delivered to a class.
204 Say N if unsure, Y to use the feature.
207 bool "Class based physical memory controller"
211 Provide the basic support for collecting physical memory usage information
212 among classes. Say Y if you want to know the memory usage of each class.
214 config CKRM_MEM_LRUORDER_CHANGE
215 bool "Change the LRU ordering of scanned pages"
217 depends on CKRM_RES_MEM
219 While trying to free pages, by default(n), scanned pages are left were they
220 are found if they belong to relatively under-used class. In this case the
221 LRU ordering of the memory subsystemis left intact. If this option is chosen,
222 then the scanned pages are moved to the tail of the list(active or inactive).
223 Changing this to yes reduces the checking overhead but violates the approximate
224 LRU order that is maintained by the paging subsystem.
226 config CKRM_TYPE_SOCKETCLASS
227 bool "Class Manager for socket groups"
230 SOCKET provides the extensions for CKRM to track per socket
231 classes. This is the base to enable socket based resource
232 control for inbound connection control, bandwidth control etc.
236 config CKRM_RES_LISTENAQ
237 tristate "Multiple Accept Queues Resource Manager"
238 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
241 Provides a resource controller for CKRM to prioritize inbound
242 connection requests. See inbound control description for
243 "IP: TCP Multiple accept queues support". If you choose that
244 option choose this option to control the queue weights.
249 tristate "Vanilla Rule-based Classification Engine (RBCE)"
250 depends on CKRM && RCFS_FS
253 Provides an optional module to support creation of rules for automatic
254 classification of kernel objects. Rules are created/deleted/modified
255 through an rcfs interface. RBCE is not required for CKRM.
260 tristate "Enhanced Rule-based Classification Engine (RBCE)"
261 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
264 Provides an optional module to support creation of rules for automatic
265 classification of kernel objects, just like RBCE above. In addition,
266 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
267 enabled) and makes information on significant kernel events available
268 to userspace tools through relayfs (requires RELAYFS_FS configured).
275 bool "Sysctl support"
277 The sysctl interface provides a means of dynamically changing
278 certain kernel parameters and variables on the fly without requiring
279 a recompile of the kernel or reboot of the system. The primary
280 interface consists of a system call, but if you say Y to "/proc
281 file system support", a tree of modifiable sysctl entries will be
282 generated beneath the /proc/sys directory. They are explained in the
283 files in <file:Documentation/sysctl/>. Note that enabling this
284 option will enlarge the kernel by at least 8 KB.
286 As it is generally a good thing, you should say Y here unless
287 building a kernel for install/rescue disks or your system is very
291 bool "Auditing support"
292 default y if SECURITY_SELINUX
295 Enable auditing infrastructure that can be used with another
296 kernel subsystem, such as SELinux (which requires this for
297 logging of avc messages output). Does not do system-call
298 auditing without CONFIG_AUDITSYSCALL.
301 bool "Enable system-call auditing support"
302 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
303 default y if SECURITY_SELINUX
306 Enable low-overhead system-call auditing infrastructure that
307 can be used independently or with another kernel subsystem,
311 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
313 default 17 if ARCH_S390
314 default 16 if X86_NUMAQ || IA64
318 Select kernel log buffer size as a power of 2.
319 Defaults and Examples:
320 17 => 128 KB for S/390
321 16 => 64 KB for x86 NUMAQ or IA-64
323 14 => 16 KB for uniprocessor
328 bool "Support for hot-pluggable devices" if !ARCH_S390
331 Say Y here if you want to plug devices into your computer while
332 the system is running, and be able to use them quickly. In many
333 cases, the devices can likewise be unplugged at any time too.
335 One well known example of this is PCMCIA- or PC-cards, credit-card
336 size devices such as network cards, modems or hard drives which are
337 plugged into slots found on all modern laptop computers. Another
338 example, used on modern desktops as well as laptops, is USB.
340 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
341 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
342 Then your kernel will automatically call out to a user mode "policy
343 agent" (/sbin/hotplug) to load modules and set up software needed
344 to use devices as you hotplug them.
347 bool "Kernel .config support"
349 This option enables the complete Linux kernel ".config" file
350 contents to be saved in the kernel. It provides documentation
351 of which kernel options are used in a running kernel or in an
352 on-disk kernel. This information can be extracted from the kernel
353 image file with the script scripts/extract-ikconfig and used as
354 input to rebuild the current kernel or to build another kernel.
355 It can also be extracted from a running kernel by reading
356 /proc/config.gz if enabled (below).
359 bool "Enable access to .config through /proc/config.gz"
360 depends on IKCONFIG && PROC_FS
362 This option enables access to the kernel configuration file
363 through /proc/config.gz.
367 bool "Configure standard kernel features (for small systems)"
369 This option allows certain base kernel options and settings
370 to be disabled or tweaked. This is for specialized
371 environments which can tolerate a "non-standard" kernel.
372 Only use this if you really know what you are doing.
375 bool "Enable delay accounting (EXPERIMENTAL)"
377 In addition to counting frequency the total delay in ns is also
378 recorded. CPU delays are specified as cpu-wait and cpu-run.
379 I/O delays are recorded for memory and regular I/O.
380 Information is accessible through /proc/<pid>/delay.
384 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
387 Say Y here to let the kernel print out symbolic crash information and
388 symbolic stack backtraces. This increases the size of the kernel
389 somewhat, as all symbols have to be loaded into the kernel image.
392 bool "Include all symbols in kallsyms"
393 depends on DEBUG_KERNEL && KALLSYMS
395 Normally kallsyms only contains the symbols of functions, for nicer
396 OOPS messages. Some debuggers can use kallsyms for other
397 symbols too: say Y here to include all symbols, and you
398 don't care about adding 300k to the size of your kernel.
402 config KALLSYMS_EXTRA_PASS
403 bool "Do an extra kallsyms pass"
406 If kallsyms is not working correctly, the build will fail with
407 inconsistent kallsyms data. If that occurs, log a bug report and
408 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
409 Always say N here unless you find a bug in kallsyms, which must be
410 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
411 you wait for kallsyms to be fixed.
414 bool "Enable futex support" if EMBEDDED
417 Disabling this option will cause the kernel to be built without
418 support for "fast userspace mutexes". The resulting kernel may not
419 run glibc-based applications correctly.
422 bool "Enable eventpoll support" if EMBEDDED
425 Disabling this option will cause the kernel to be built without
426 support for epoll family of system calls.
428 source "drivers/block/Kconfig.iosched"
430 config CC_OPTIMIZE_FOR_SIZE
431 bool "Optimize for size"
432 default y if ARM || H8300
435 Enabling this option will pass "-Os" instead of "-O2" to gcc
436 resulting in a smaller kernel.
438 WARNING: some versions of gcc may generate incorrect code with this
439 option. If problems are observed, a gcc upgrade may be needed.
443 endmenu # General setup
446 menu "Loadable module support"
449 bool "Enable loadable module support"
451 Kernel modules are small pieces of compiled code which can
452 be inserted in the running kernel, rather than being
453 permanently built into the kernel. You use the "modprobe"
454 tool to add (and sometimes remove) them. If you say Y here,
455 many parts of the kernel can be built as modules (by
456 answering M instead of Y where indicated): this is most
457 useful for infrequently used options which are not required
458 for booting. For more information, see the man pages for
459 modprobe, lsmod, modinfo, insmod and rmmod.
461 If you say Y here, you will need to run "make
462 modules_install" to put the modules under /lib/modules/
463 where modprobe can find them (you may need to be root to do
469 bool "Module unloading"
472 Without this option you will not be able to unload any
473 modules (note that some modules may not be unloadable
474 anyway), which makes your kernel slightly smaller and
475 simpler. If unsure, say Y.
477 config MODULE_FORCE_UNLOAD
478 bool "Forced module unloading"
479 depends on MODULE_UNLOAD && EXPERIMENTAL
481 This option allows you to force a module to unload, even if the
482 kernel believes it is unsafe: the kernel will remove the module
483 without waiting for anyone to stop using it (using the -f option to
484 rmmod). This is mainly for kernel developers and desperate users.
487 config OBSOLETE_MODPARM
492 You need this option to use module parameters on modules which
493 have not been converted to the new module parameter system yet.
497 bool "Module versioning support (EXPERIMENTAL)"
498 depends on MODULES && EXPERIMENTAL
500 Usually, you have to use modules compiled with your kernel.
501 Saying Y here makes it sometimes possible to use modules
502 compiled for different kernels, by adding enough information
503 to the modules to (hopefully) spot any changes which would
504 make them incompatible with the kernel you are running. If
508 bool "Module signature verification (EXPERIMENTAL)"
509 depends on MODULES && EXPERIMENTAL
511 select CRYPTO_SIGNATURE
513 Check modules for valid signatures upon load.
515 config MODULE_SIG_FORCE
516 bool "Required modules to be validly signed (EXPERIMENTAL)"
517 depends on MODULE_SIG
519 Reject unsigned modules or signed modules for which we don't have a
523 bool "Automatic kernel module loading"
526 Normally when you have selected some parts of the kernel to
527 be created as kernel modules, you must load them (using the
528 "modprobe" command) before you can use them. If you say Y
529 here, some parts of the kernel will be able to load modules
530 automatically: when a part of the kernel needs a module, it
531 runs modprobe with the appropriate arguments, thereby
532 loading the module if it is available. If unsure, say Y.
537 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
539 Need stop_machine() primitive.