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24 drivers that have been replaced by something else, and/or are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
55 depends on SMP || PREEMPT
63 string "Local version - append to kernel release"
65 Append an extra string to the end of your kernel version.
66 This will show up when you type uname, for example.
67 The string you set here will be appended after the contents of
68 any files with a filename matching localversion* in your
69 object and source tree, in that order. Your total string can
70 be a maximum of 64 characters.
73 bool "Support for paging of anonymous memory (swap)"
77 This option allows you to choose whether you want to have support
78 for socalled swap devices or swap files in your kernel that are
79 used to provide more virtual memory than the actual RAM present
80 in your computer. If unsure say Y.
86 Inter Process Communication is a suite of library functions and
87 system calls which let processes (running programs) synchronize and
88 exchange information. It is generally considered to be a good thing,
89 and some programs won't run unless you say Y here. In particular, if
90 you want to run the DOS emulator dosemu under Linux (read the
91 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
92 you'll need to say Y here.
94 You can find documentation about IPC with "info ipc" and also in
95 section 6.4 of the Linux Programmer's Guide, available from
96 <http://www.tldp.org/guides.html>.
99 bool "POSIX Message Queues"
100 depends on NET && EXPERIMENTAL
102 POSIX variant of message queues is a part of IPC. In POSIX message
103 queues every message has a priority which decides about succession
104 of receiving it by a process. If you want to compile and run
105 programs written e.g. for Solaris with use of its POSIX message
106 queues (functions mq_*) say Y here. To use this feature you will
107 also need mqueue library, available from
108 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
110 POSIX message queues are visible as a filesystem called 'mqueue'
111 and can be mounted somewhere if you want to do filesystem
112 operations on message queues.
116 config BSD_PROCESS_ACCT
117 bool "BSD Process Accounting"
119 If you say Y here, a user level program will be able to instruct the
120 kernel (via a special system call) to write process accounting
121 information to a file: whenever a process exits, information about
122 that process will be appended to the file by the kernel. The
123 information includes things such as creation time, owning user,
124 command name, memory usage, controlling terminal etc. (the complete
125 list is in the struct acct in <file:include/linux/acct.h>). It is
126 up to the user level program to do useful things with this
127 information. This is generally a good idea, so say Y.
129 config BSD_PROCESS_ACCT_V3
130 bool "BSD Process Accounting version 3 file format"
131 depends on BSD_PROCESS_ACCT
134 If you say Y here, the process accounting information is written
135 in a new file format that also logs the process IDs of each
136 process and it's parent. Note that this file format is incompatible
137 with previous v0/v1/v2 file formats, so you will need updated tools
138 for processing it. A preliminary version of these tools is available
139 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
141 menu "Class Based Kernel Resource Management"
144 bool "Class Based Kernel Resource Management Core"
145 depends on EXPERIMENTAL
147 Class-based Kernel Resource Management is a framework for controlling
148 and monitoring resource allocation of user-defined groups of tasks or
149 incoming socket connections. For more information, please visit
152 If you say Y here, enable the Resource Class File System and atleast
153 one of the resource controllers below. Say N if you are unsure.
156 tristate "Resource Class File System (User API)"
159 RCFS is the filesystem API for CKRM. This separate configuration
160 option is provided only for debugging and will eventually disappear
161 since rcfs will be automounted whenever CKRM is configured.
163 Say N if unsure, Y if you've enabled CKRM, M to debug rcfs
166 config CKRM_TYPE_TASKCLASS
167 bool "Class Manager for Task Groups"
168 depends on CKRM && RCFS_FS
170 TASKCLASS provides the extensions for CKRM to track task classes
171 This is the base to enable task class based resource control for
172 cpu, memory and disk I/O.
177 bool "Class based physical memory controller"
181 Provide the basic support for collecting physical memory usage
182 information among classes. Say Y if you want to know the memory
185 config CKRM_TYPE_SOCKETCLASS
186 bool "Class Manager for socket groups"
187 depends on CKRM && RCFS_FS
189 SOCKET provides the extensions for CKRM to track per socket
190 classes. This is the base to enable socket based resource
191 control for inbound connection control, bandwidth control etc.
195 config CKRM_RES_NUMTASKS
196 tristate "Number of Tasks Resource Manager"
197 depends on CKRM_TYPE_TASKCLASS
200 Provides a Resource Controller for CKRM that allows limiting no of
201 tasks a task class can have.
203 Say N if unsure, Y to use the feature.
205 config CKRM_RES_LISTENAQ
206 tristate "Multiple Accept Queues Resource Manager"
207 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
210 Provides a resource controller for CKRM to prioritize inbound
211 connection requests. See inbound control description for
212 "IP: TCP Multiple accept queues support". If you choose that
213 option choose this option to control the queue weights.
218 prompt "Classification Engine"
219 depends on CKRM && RCFS_FS
222 Select a classification engine (CE) that assists in
223 automatic classification of kernel objects managed by CKRM when
224 they are created. Without a CE, a user must manually
225 classify objects into classes. Processes inherit their parent's
228 Only one engine can be built into the kernel though all can be
229 built as modules (only one will load).
234 tristate "Vanilla RBCE"
236 Vanilla Rule-based Classification Engine (RBCE). Rules for
237 classifying kernel objects are created/deleted/modified through
238 a RCFS directory using a filesystem interface.
240 Any CE is optional. If unsure, say N.
243 tristate "Enhanced RBCE"
244 depends on DELAY_ACCT && RELAYFS_FS
246 Enhanced Rule-based Classification Engine (CRBCE). Like the Vanilla
247 RBCE, rules for classifying kernel objects are created, deleted and
248 modified through a RCFS directory using a filesystem interface
249 (requires CKRM_RCFS configured).
251 In addition, CRBCE provides per-process delay data
252 (requires DELAY_ACCT configured) and makes information on significant
253 kernel events available to userspace tools through relayfs
254 (requires RELAYFS_FS configured).
256 Any CE is optional. If unsure, say N.
263 bool "Sysctl support"
265 The sysctl interface provides a means of dynamically changing
266 certain kernel parameters and variables on the fly without requiring
267 a recompile of the kernel or reboot of the system. The primary
268 interface consists of a system call, but if you say Y to "/proc
269 file system support", a tree of modifiable sysctl entries will be
270 generated beneath the /proc/sys directory. They are explained in the
271 files in <file:Documentation/sysctl/>. Note that enabling this
272 option will enlarge the kernel by at least 8 KB.
274 As it is generally a good thing, you should say Y here unless
275 building a kernel for install/rescue disks or your system is very
279 bool "Auditing support"
280 default y if SECURITY_SELINUX
283 Enable auditing infrastructure that can be used with another
284 kernel subsystem, such as SELinux (which requires this for
285 logging of avc messages output). Does not do system-call
286 auditing without CONFIG_AUDITSYSCALL.
289 bool "Enable system-call auditing support"
290 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
291 default y if SECURITY_SELINUX
294 Enable low-overhead system-call auditing infrastructure that
295 can be used independently or with another kernel subsystem,
299 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
301 default 17 if ARCH_S390
302 default 16 if X86_NUMAQ || IA64
306 Select kernel log buffer size as a power of 2.
307 Defaults and Examples:
308 17 => 128 KB for S/390
309 16 => 64 KB for x86 NUMAQ or IA-64
311 14 => 16 KB for uniprocessor
316 bool "Support for hot-pluggable devices" if !ARCH_S390
319 Say Y here if you want to plug devices into your computer while
320 the system is running, and be able to use them quickly. In many
321 cases, the devices can likewise be unplugged at any time too.
323 One well known example of this is PCMCIA- or PC-cards, credit-card
324 size devices such as network cards, modems or hard drives which are
325 plugged into slots found on all modern laptop computers. Another
326 example, used on modern desktops as well as laptops, is USB.
328 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
329 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
330 Then your kernel will automatically call out to a user mode "policy
331 agent" (/sbin/hotplug) to load modules and set up software needed
332 to use devices as you hotplug them.
334 config KOBJECT_UEVENT
335 bool "Kernel Userspace Events"
339 This option enables the kernel userspace event layer, which is a
340 simple mechanism for kernel-to-user communication over a netlink
342 The goal of the kernel userspace events layer is to provide a simple
343 and efficient events system, that notifies userspace about kobject
344 state changes. This will enable applications to just listen for
345 events instead of polling system devices and files.
346 Hotplug events (kobject addition and removal) are also available on
347 the netlink socket in addition to the execution of /sbin/hotplug if
348 CONFIG_HOTPLUG is enabled.
350 Say Y, unless you are building a system requiring minimal memory
354 bool "Kernel .config support"
356 This option enables the complete Linux kernel ".config" file
357 contents to be saved in the kernel. It provides documentation
358 of which kernel options are used in a running kernel or in an
359 on-disk kernel. This information can be extracted from the kernel
360 image file with the script scripts/extract-ikconfig and used as
361 input to rebuild the current kernel or to build another kernel.
362 It can also be extracted from a running kernel by reading
363 /proc/config.gz if enabled (below).
366 bool "Enable access to .config through /proc/config.gz"
367 depends on IKCONFIG && PROC_FS
369 This option enables access to the kernel configuration file
370 through /proc/config.gz.
374 bool "Configure standard kernel features (for small systems)"
376 This option allows certain base kernel options and settings
377 to be disabled or tweaked. This is for specialized
378 environments which can tolerate a "non-standard" kernel.
379 Only use this if you really know what you are doing.
382 bool "Enable delay accounting (EXPERIMENTAL)"
384 In addition to counting frequency the total delay in ns is also
385 recorded. CPU delays are specified as cpu-wait and cpu-run.
386 I/O delays are recorded for memory and regular I/O.
387 Information is accessible through /proc/<pid>/delay.
390 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
393 Say Y here to let the kernel print out symbolic crash information and
394 symbolic stack backtraces. This increases the size of the kernel
395 somewhat, as all symbols have to be loaded into the kernel image.
398 bool "Include all symbols in kallsyms"
399 depends on DEBUG_KERNEL && KALLSYMS
401 Normally kallsyms only contains the symbols of functions, for nicer
402 OOPS messages. Some debuggers can use kallsyms for other
403 symbols too: say Y here to include all symbols, and you
404 don't care about adding 300k to the size of your kernel.
408 config KALLSYMS_EXTRA_PASS
409 bool "Do an extra kallsyms pass"
412 If kallsyms is not working correctly, the build will fail with
413 inconsistent kallsyms data. If that occurs, log a bug report and
414 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
415 Always say N here unless you find a bug in kallsyms, which must be
416 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
417 you wait for kallsyms to be fixed.
420 bool "Enable futex support" if EMBEDDED
423 Disabling this option will cause the kernel to be built without
424 support for "fast userspace mutexes". The resulting kernel may not
425 run glibc-based applications correctly.
428 bool "Enable eventpoll support" if EMBEDDED
431 Disabling this option will cause the kernel to be built without
432 support for epoll family of system calls.
434 config CC_OPTIMIZE_FOR_SIZE
435 bool "Optimize for size" if EMBEDDED
436 default y if ARM || H8300
439 Enabling this option will pass "-Os" instead of "-O2" to gcc
440 resulting in a smaller kernel.
442 WARNING: some versions of gcc may generate incorrect code with this
443 option. If problems are observed, a gcc upgrade may be needed.
449 bool "Use full shmem filesystem" if EMBEDDED && MMU
451 The shmem is an internal filesystem used to manage shared memory.
452 It is backed by swap and manages resource limits. It is also exported
453 to userspace as tmpfs if TMPFS is enabled. Disabling this
454 option replaces shmem and tmpfs with the much simpler ramfs code,
455 which may be appropriate on small systems without swap.
457 config CC_ALIGN_FUNCTIONS
458 int "Function alignment" if EMBEDDED
461 Align the start of functions to the next power-of-two greater than n,
462 skipping up to n bytes. For instance, 32 aligns functions
463 to the next 32-byte boundary, but 24 would align to the next
464 32-byte boundary only if this can be done by skipping 23 bytes or less.
465 Zero means use compiler's default.
467 config CC_ALIGN_LABELS
468 int "Label alignment" if EMBEDDED
471 Align all branch targets to a power-of-two boundary, skipping
472 up to n bytes like ALIGN_FUNCTIONS. This option can easily
473 make code slower, because it must insert dummy operations for
474 when the branch target is reached in the usual flow of the code.
475 Zero means use compiler's default.
477 config CC_ALIGN_LOOPS
478 int "Loop alignment" if EMBEDDED
481 Align loops to a power-of-two boundary, skipping up to n bytes.
482 Zero means use compiler's default.
484 config CC_ALIGN_JUMPS
485 int "Jump alignment" if EMBEDDED
488 Align branch targets to a power-of-two boundary, for branch
489 targets where the targets can only be reached by jumping,
490 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
491 no dummy operations need be executed.
492 Zero means use compiler's default.
494 endmenu # General setup
500 menu "Loadable module support"
503 bool "Enable loadable module support"
505 Kernel modules are small pieces of compiled code which can
506 be inserted in the running kernel, rather than being
507 permanently built into the kernel. You use the "modprobe"
508 tool to add (and sometimes remove) them. If you say Y here,
509 many parts of the kernel can be built as modules (by
510 answering M instead of Y where indicated): this is most
511 useful for infrequently used options which are not required
512 for booting. For more information, see the man pages for
513 modprobe, lsmod, modinfo, insmod and rmmod.
515 If you say Y here, you will need to run "make
516 modules_install" to put the modules under /lib/modules/
517 where modprobe can find them (you may need to be root to do
523 bool "Module unloading"
526 Without this option you will not be able to unload any
527 modules (note that some modules may not be unloadable
528 anyway), which makes your kernel slightly smaller and
529 simpler. If unsure, say Y.
531 config MODULE_FORCE_UNLOAD
532 bool "Forced module unloading"
533 depends on MODULE_UNLOAD && EXPERIMENTAL
535 This option allows you to force a module to unload, even if the
536 kernel believes it is unsafe: the kernel will remove the module
537 without waiting for anyone to stop using it (using the -f option to
538 rmmod). This is mainly for kernel developers and desperate users.
541 config OBSOLETE_MODPARM
546 You need this option to use module parameters on modules which
547 have not been converted to the new module parameter system yet.
551 bool "Module versioning support (EXPERIMENTAL)"
552 depends on MODULES && EXPERIMENTAL
554 Usually, you have to use modules compiled with your kernel.
555 Saying Y here makes it sometimes possible to use modules
556 compiled for different kernels, by adding enough information
557 to the modules to (hopefully) spot any changes which would
558 make them incompatible with the kernel you are running. If
561 config MODULE_SRCVERSION_ALL
562 bool "Source checksum for all modules"
565 Modules which contain a MODULE_VERSION get an extra "srcversion"
566 field inserted into their modinfo section, which contains a
567 sum of the source files which made it. This helps maintainers
568 see exactly which source was used to build a module (since
569 others sometimes change the module source without updating
570 the version). With this option, such a "srcversion" field
571 will be created for all modules. If unsure, say N.
574 bool "Automatic kernel module loading"
577 Normally when you have selected some parts of the kernel to
578 be created as kernel modules, you must load them (using the
579 "modprobe" command) before you can use them. If you say Y
580 here, some parts of the kernel will be able to load modules
581 automatically: when a part of the kernel needs a module, it
582 runs modprobe with the appropriate arguments, thereby
583 loading the module if it is available. If unsure, say Y.
588 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
590 Need stop_machine() primitive.