1 menu "Code maturity level options"
4 bool "Prompt for development and/or incomplete code/drivers"
6 Some of the various things that Linux supports (such as network
7 drivers, file systems, network protocols, etc.) can be in a state
8 of development where the functionality, stability, or the level of
9 testing is not yet high enough for general use. This is usually
10 known as the "alpha-test" phase among developers. If a feature is
11 currently in alpha-test, then the developers usually discourage
12 uninformed widespread use of this feature by the general public to
13 avoid "Why doesn't this work?" type mail messages. However, active
14 testing and use of these systems is welcomed. Just be aware that it
15 may not meet the normal level of reliability or it may fail to work
16 in some special cases. Detailed bug reports from people familiar
17 with the kernel internals are usually welcomed by the developers
18 (before submitting bug reports, please read the documents
19 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
20 <file:Documentation/BUG-HUNTING>, and
21 <file:Documentation/oops-tracing.txt> in the kernel source).
23 This option will also make obsoleted drivers available. These are
24 drivers that have been replaced by something else, and/or are
25 scheduled to be removed in a future kernel release.
27 Unless you intend to help test and develop a feature or driver that
28 falls into this category, or you have a situation that requires
29 using these features, you should probably say N here, which will
30 cause the configurator to present you with fewer choices. If
31 you say Y here, you will be offered the choice of using features or
32 drivers that are currently considered to be in the alpha-test phase.
35 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
38 Select this option if you don't even want to see the option
39 to configure known-broken drivers.
45 depends on !CLEAN_COMPILE
50 depends on BROKEN || !SMP
58 string "Local version - append to kernel release"
60 Append an extra string to the end of your kernel version.
61 This will show up when you type uname, for example.
62 The string you set here will be appended after the contents of
63 any files with a filename matching localversion* in your
64 object and source tree, in that order. Your total string can
65 be a maximum of 64 characters.
68 bool "Support for paging of anonymous memory (swap)"
72 This option allows you to choose whether you want to have support
73 for socalled swap devices or swap files in your kernel that are
74 used to provide more virtual memory than the actual RAM present
75 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 config BSD_PROCESS_ACCT_V3
127 bool "BSD Process Accounting version 3 file format"
128 depends on BSD_PROCESS_ACCT
131 If you say Y here, the process accounting information is written
132 in a new file format that also logs the process IDs of each
133 process and it's parent. Note that this file format is incompatible
134 with previous v0/v1/v2 file formats, so you will need updated tools
135 for processing it. A preliminary version of these tools is available
136 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
138 menu "Class Based Kernel Resource Management"
141 bool "Class Based Kernel Resource Management Core"
142 depends on EXPERIMENTAL
144 Class-based Kernel Resource Management is a framework for controlling
145 and monitoring resource allocation of user-defined groups of tasks or
146 incoming socket connections. For more information, please visit
149 If you say Y here, enable the Resource Class File System and atleast
150 one of the resource controllers below. Say N if you are unsure.
153 tristate "Resource Class File System (User API)"
156 RCFS is the filesystem API for CKRM. This separate configuration
157 option is provided only for debugging and will eventually disappear
158 since rcfs will be automounted whenever CKRM is configured.
160 Say N if unsure, Y if you've enabled CKRM, M to debug rcfs
163 config CKRM_TYPE_TASKCLASS
164 bool "Class Manager for Task Groups"
167 TASKCLASS provides the extensions for CKRM to track task classes
168 This is the base to enable task class based resource control for
169 cpu, memory and disk I/O.
173 config CKRM_RES_NUMTASKS
174 tristate "Number of Tasks Resource Manager"
175 depends on CKRM_TYPE_TASKCLASS
178 Provides a Resource Controller for CKRM that allows limiting no of
179 tasks a task class can have.
181 Say N if unsure, Y to use the feature.
183 config CKRM_CPU_SCHEDULE
184 bool "CKRM CPU scheduler"
185 depends on CKRM_TYPE_TASKCLASS
188 Use CKRM CPU scheduler instead of Linux Scheduler
190 Say N if unsure, Y to use the feature.
192 config CKRM_RES_BLKIO
193 tristate " Disk I/O Resource Controller"
194 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
197 Provides a resource controller for best-effort block I/O
198 bandwidth control. The controller attempts this by proportional
199 servicing of requests in the I/O scheduler. However, seek
200 optimizations and reordering by device drivers/disk controllers may
201 alter the actual bandwidth delivered to a class.
203 Say N if unsure, Y to use the feature.
206 bool "Class based physical memory controller"
210 Provide the basic support for collecting physical memory usage information
211 among classes. Say Y if you want to know the memory usage of each class.
213 config CKRM_MEM_LRUORDER_CHANGE
214 bool "Change the LRU ordering of scanned pages"
216 depends on CKRM_RES_MEM
218 While trying to free pages, by default(n), scanned pages are left were they
219 are found if they belong to relatively under-used class. In this case the
220 LRU ordering of the memory subsystemis left intact. If this option is chosen,
221 then the scanned pages are moved to the tail of the list(active or inactive).
222 Changing this to yes reduces the checking overhead but violates the approximate
223 LRU order that is maintained by the paging subsystem.
225 config CKRM_CPU_SCHEDULE_AT_BOOT
226 bool "Turn on at boot time"
227 depends on CKRM_CPU_SCHEDULE
230 Enable CKRM CPU Scheduler at boot time. Otherwise
231 it can be turned on dynamically at runtime. If not
232 turned on the default Linux Scheduler behavior
235 Say N if unsure, Y to use this feature
237 config CKRM_TYPE_SOCKETCLASS
238 bool "Class Manager for socket groups"
241 SOCKET provides the extensions for CKRM to track per socket
242 classes. This is the base to enable socket based resource
243 control for inbound connection control, bandwidth control etc.
247 config CKRM_RES_LISTENAQ
248 tristate "Multiple Accept Queues Resource Manager"
249 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
252 Provides a resource controller for CKRM to prioritize inbound
253 connection requests. See inbound control description for
254 "IP: TCP Multiple accept queues support". If you choose that
255 option choose this option to control the queue weights.
260 tristate "Vanilla Rule-based Classification Engine (RBCE)"
261 depends on CKRM && RCFS_FS
264 Provides an optional module to support creation of rules for automatic
265 classification of kernel objects. Rules are created/deleted/modified
266 through an rcfs interface. RBCE is not required for CKRM.
271 tristate "Enhanced Rule-based Classification Engine (RBCE)"
272 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
275 Provides an optional module to support creation of rules for automatic
276 classification of kernel objects, just like RBCE above. In addition,
277 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
278 enabled) and makes information on significant kernel events available
279 to userspace tools through relayfs (requires RELAYFS_FS configured).
286 bool "Sysctl support"
288 The sysctl interface provides a means of dynamically changing
289 certain kernel parameters and variables on the fly without requiring
290 a recompile of the kernel or reboot of the system. The primary
291 interface consists of a system call, but if you say Y to "/proc
292 file system support", a tree of modifiable sysctl entries will be
293 generated beneath the /proc/sys directory. They are explained in the
294 files in <file:Documentation/sysctl/>. Note that enabling this
295 option will enlarge the kernel by at least 8 KB.
297 As it is generally a good thing, you should say Y here unless
298 building a kernel for install/rescue disks or your system is very
302 bool "Auditing support"
303 default y if SECURITY_SELINUX
306 Enable auditing infrastructure that can be used with another
307 kernel subsystem, such as SELinux (which requires this for
308 logging of avc messages output). Does not do system-call
309 auditing without CONFIG_AUDITSYSCALL.
312 bool "Enable system-call auditing support"
313 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
314 default y if SECURITY_SELINUX
317 Enable low-overhead system-call auditing infrastructure that
318 can be used independently or with another kernel subsystem,
322 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
324 default 17 if ARCH_S390
325 default 16 if X86_NUMAQ || IA64
329 Select kernel log buffer size as a power of 2.
330 Defaults and Examples:
331 17 => 128 KB for S/390
332 16 => 64 KB for x86 NUMAQ or IA-64
334 14 => 16 KB for uniprocessor
339 bool "Support for hot-pluggable devices" if !ARCH_S390
342 Say Y here if you want to plug devices into your computer while
343 the system is running, and be able to use them quickly. In many
344 cases, the devices can likewise be unplugged at any time too.
346 One well known example of this is PCMCIA- or PC-cards, credit-card
347 size devices such as network cards, modems or hard drives which are
348 plugged into slots found on all modern laptop computers. Another
349 example, used on modern desktops as well as laptops, is USB.
351 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
352 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
353 Then your kernel will automatically call out to a user mode "policy
354 agent" (/sbin/hotplug) to load modules and set up software needed
355 to use devices as you hotplug them.
358 bool "Kernel .config support"
360 This option enables the complete Linux kernel ".config" file
361 contents to be saved in the kernel. It provides documentation
362 of which kernel options are used in a running kernel or in an
363 on-disk kernel. This information can be extracted from the kernel
364 image file with the script scripts/extract-ikconfig and used as
365 input to rebuild the current kernel or to build another kernel.
366 It can also be extracted from a running kernel by reading
367 /proc/config.gz if enabled (below).
370 bool "Enable access to .config through /proc/config.gz"
371 depends on IKCONFIG && PROC_FS
373 This option enables access to the kernel configuration file
374 through /proc/config.gz.
380 This option enables panic() to be called when a system is out of
381 memory. This feature along with /proc/sys/kernel/panic allows a
382 different behavior on out-of-memory conditions when the standard
383 behavior (killing processes in an attempt to recover) does not
390 depends on !OOM_PANIC
394 bool "Configure standard kernel features (for small systems)"
396 This option allows certain base kernel options and settings
397 to be disabled or tweaked. This is for specialized
398 environments which can tolerate a "non-standard" kernel.
399 Only use this if you really know what you are doing.
402 bool "Enable delay accounting (EXPERIMENTAL)"
404 In addition to counting frequency the total delay in ns is also
405 recorded. CPU delays are specified as cpu-wait and cpu-run.
406 I/O delays are recorded for memory and regular I/O.
407 Information is accessible through /proc/<pid>/delay.
411 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
414 Say Y here to let the kernel print out symbolic crash information and
415 symbolic stack backtraces. This increases the size of the kernel
416 somewhat, as all symbols have to be loaded into the kernel image.
419 bool "Include all symbols in kallsyms"
420 depends on DEBUG_KERNEL && KALLSYMS
422 Normally kallsyms only contains the symbols of functions, for nicer
423 OOPS messages. Some debuggers can use kallsyms for other
424 symbols too: say Y here to include all symbols, and you
425 don't care about adding 300k to the size of your kernel.
429 config KALLSYMS_EXTRA_PASS
430 bool "Do an extra kallsyms pass"
433 If kallsyms is not working correctly, the build will fail with
434 inconsistent kallsyms data. If that occurs, log a bug report and
435 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
436 Always say N here unless you find a bug in kallsyms, which must be
437 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
438 you wait for kallsyms to be fixed.
441 bool "Enable futex support" if EMBEDDED
444 Disabling this option will cause the kernel to be built without
445 support for "fast userspace mutexes". The resulting kernel may not
446 run glibc-based applications correctly.
449 bool "Enable eventpoll support" if EMBEDDED
452 Disabling this option will cause the kernel to be built without
453 support for epoll family of system calls.
455 source "drivers/block/Kconfig.iosched"
457 config CC_OPTIMIZE_FOR_SIZE
458 bool "Optimize for size"
459 default y if ARM || H8300
462 Enabling this option will pass "-Os" instead of "-O2" to gcc
463 resulting in a smaller kernel.
465 WARNING: some versions of gcc may generate incorrect code with this
466 option. If problems are observed, a gcc upgrade may be needed.
472 bool "Use full shmem filesystem" if EMBEDDED && MMU
474 The shmem is an internal filesystem used to manage shared memory.
475 It is backed by swap and manages resource limits. It is also exported
476 to userspace as tmpfs if TMPFS is enabled. Disabling this
477 option replaces shmem and tmpfs with the much simpler ramfs code,
478 which may be appropriate on small systems without swap.
480 endmenu # General setup
486 menu "Loadable module support"
489 bool "Enable loadable module support"
491 Kernel modules are small pieces of compiled code which can
492 be inserted in the running kernel, rather than being
493 permanently built into the kernel. You use the "modprobe"
494 tool to add (and sometimes remove) them. If you say Y here,
495 many parts of the kernel can be built as modules (by
496 answering M instead of Y where indicated): this is most
497 useful for infrequently used options which are not required
498 for booting. For more information, see the man pages for
499 modprobe, lsmod, modinfo, insmod and rmmod.
501 If you say Y here, you will need to run "make
502 modules_install" to put the modules under /lib/modules/
503 where modprobe can find them (you may need to be root to do
509 bool "Module unloading"
512 Without this option you will not be able to unload any
513 modules (note that some modules may not be unloadable
514 anyway), which makes your kernel slightly smaller and
515 simpler. If unsure, say Y.
517 config MODULE_FORCE_UNLOAD
518 bool "Forced module unloading"
519 depends on MODULE_UNLOAD && EXPERIMENTAL
521 This option allows you to force a module to unload, even if the
522 kernel believes it is unsafe: the kernel will remove the module
523 without waiting for anyone to stop using it (using the -f option to
524 rmmod). This is mainly for kernel developers and desperate users.
527 config OBSOLETE_MODPARM
532 You need this option to use module parameters on modules which
533 have not been converted to the new module parameter system yet.
537 bool "Module versioning support (EXPERIMENTAL)"
538 depends on MODULES && EXPERIMENTAL
540 Usually, you have to use modules compiled with your kernel.
541 Saying Y here makes it sometimes possible to use modules
542 compiled for different kernels, by adding enough information
543 to the modules to (hopefully) spot any changes which would
544 make them incompatible with the kernel you are running. If
548 bool "Module signature verification (EXPERIMENTAL)"
549 depends on MODULES && EXPERIMENTAL
552 select CRYPTO_SIGNATURE
554 Check modules for valid signatures upon load.
556 config MODULE_SIG_FORCE
557 bool "Required modules to be validly signed (EXPERIMENTAL)"
558 depends on MODULE_SIG
560 Reject unsigned modules or signed modules for which we don't have a
564 bool "Automatic kernel module loading"
567 Normally when you have selected some parts of the kernel to
568 be created as kernel modules, you must load them (using the
569 "modprobe" command) before you can use them. If you say Y
570 here, some parts of the kernel will be able to load modules
571 automatically: when a part of the kernel needs a module, it
572 runs modprobe with the appropriate arguments, thereby
573 loading the module if it is available. If unsure, say Y.
578 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
580 Need stop_machine() primitive.