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24 drivers that have been replaced by something else, and/or are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 tristate "Null Tasks Resource Manager"
178 depends on CKRM_TYPE_TASKCLASS
182 bool "Class based physical memory controller"
186 Provide the basic support for collecting physical memory usage
187 information among classes. Say Y if you want to know the memory
190 config CKRM_TYPE_SOCKETCLASS
191 bool "Class Manager for socket groups"
192 depends on CKRM && RCFS_FS
194 Provides a Null Resource Controller for CKRM that is purely for
195 demonstration purposes.
197 Say N if unsure, Y to use the feature.
200 config CKRM_RES_NUMTASKS
201 tristate "Number of Tasks Resource Manager"
202 depends on CKRM_TYPE_TASKCLASS
205 Provides a Resource Controller for CKRM that allows limiting no of
206 tasks a task class can have.
208 Say N if unsure, Y to use the feature.
210 config CKRM_CPU_SCHEDULE
211 bool "CKRM CPU scheduler"
212 depends on CKRM_TYPE_TASKCLASS
215 Use CKRM CPU scheduler instead of Linux Scheduler
217 Say N if unsure, Y to use the feature.
219 config CKRM_RES_BLKIO
220 tristate " Disk I/O Resource Controller"
221 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
224 Provides a resource controller for best-effort block I/O
225 bandwidth control. The controller attempts this by proportional
226 servicing of requests in the I/O scheduler. However, seek
227 optimizations and reordering by device drivers/disk controllers may
228 alter the actual bandwidth delivered to a class.
230 Say N if unsure, Y to use the feature.
232 config CKRM_CPU_SCHEDULE_AT_BOOT
233 bool "Turn on at boot time"
234 depends on CKRM_CPU_SCHEDULE
237 Enable CKRM CPU Scheduler at boot time. Otherwise
238 it can be turned on dynamically at runtime. If not
239 turned on the default Linux Scheduler behavior
242 Say N if unsure, Y to use this feature
244 config CKRM_TYPE_SOCKETCLASS
245 bool "Class Manager for socket groups"
248 SOCKET provides the extensions for CKRM to track per socket
249 classes. This is the base to enable socket based resource
250 control for inbound connection control, bandwidth control etc.
254 config CKRM_RES_LISTENAQ
255 tristate "Multiple Accept Queues Resource Manager"
256 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
259 Provides a resource controller for CKRM to prioritize inbound
260 connection requests. See inbound control description for
261 "IP: TCP Multiple accept queues support". If you choose that
262 option choose this option to control the queue weights.
267 prompt "Classification Engine"
268 depends on CKRM && RCFS_FS
271 Select a classification engine (CE) that assists in
272 automatic classification of kernel objects managed by CKRM when
273 they are created. Without a CE, a user must manually
274 classify objects into classes. Processes inherit their parent's
277 Only one engine can be built into the kernel though all can be
278 built as modules (only one will load).
283 tristate "Vanilla RBCE"
285 Vanilla Rule-based Classification Engine (RBCE). Rules for
286 classifying kernel objects are created/deleted/modified through
287 a RCFS directory using a filesystem interface.
289 Any CE is optional. If unsure, say N.
292 tristate "Enhanced RBCE"
293 depends on DELAY_ACCT && RELAYFS_FS
295 Enhanced Rule-based Classification Engine (CRBCE). Like the Vanilla
296 RBCE, rules for classifying kernel objects are created, deleted and
297 modified through a RCFS directory using a filesystem interface
298 (requires CKRM_RCFS configured).
300 In addition, CRBCE provides per-process delay data
301 (requires DELAY_ACCT configured) and makes information on significant
302 kernel events available to userspace tools through relayfs
303 (requires RELAYFS_FS configured).
305 Any CE is optional. If unsure, say N.
312 bool "Sysctl support"
314 The sysctl interface provides a means of dynamically changing
315 certain kernel parameters and variables on the fly without requiring
316 a recompile of the kernel or reboot of the system. The primary
317 interface consists of a system call, but if you say Y to "/proc
318 file system support", a tree of modifiable sysctl entries will be
319 generated beneath the /proc/sys directory. They are explained in the
320 files in <file:Documentation/sysctl/>. Note that enabling this
321 option will enlarge the kernel by at least 8 KB.
323 As it is generally a good thing, you should say Y here unless
324 building a kernel for install/rescue disks or your system is very
328 bool "Auditing support"
329 default y if SECURITY_SELINUX
332 Enable auditing infrastructure that can be used with another
333 kernel subsystem, such as SELinux (which requires this for
334 logging of avc messages output). Does not do system-call
335 auditing without CONFIG_AUDITSYSCALL.
338 bool "Enable system-call auditing support"
339 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
340 default y if SECURITY_SELINUX
343 Enable low-overhead system-call auditing infrastructure that
344 can be used independently or with another kernel subsystem,
348 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
350 default 17 if ARCH_S390
351 default 16 if X86_NUMAQ || IA64
355 Select kernel log buffer size as a power of 2.
356 Defaults and Examples:
357 17 => 128 KB for S/390
358 16 => 64 KB for x86 NUMAQ or IA-64
360 14 => 16 KB for uniprocessor
365 bool "Support for hot-pluggable devices" if !ARCH_S390
368 Say Y here if you want to plug devices into your computer while
369 the system is running, and be able to use them quickly. In many
370 cases, the devices can likewise be unplugged at any time too.
372 One well known example of this is PCMCIA- or PC-cards, credit-card
373 size devices such as network cards, modems or hard drives which are
374 plugged into slots found on all modern laptop computers. Another
375 example, used on modern desktops as well as laptops, is USB.
377 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
378 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
379 Then your kernel will automatically call out to a user mode "policy
380 agent" (/sbin/hotplug) to load modules and set up software needed
381 to use devices as you hotplug them.
383 config KOBJECT_UEVENT
384 bool "Kernel Userspace Events"
388 This option enables the kernel userspace event layer, which is a
389 simple mechanism for kernel-to-user communication over a netlink
391 The goal of the kernel userspace events layer is to provide a simple
392 and efficient events system, that notifies userspace about kobject
393 state changes. This will enable applications to just listen for
394 events instead of polling system devices and files.
395 Hotplug events (kobject addition and removal) are also available on
396 the netlink socket in addition to the execution of /sbin/hotplug if
397 CONFIG_HOTPLUG is enabled.
399 Say Y, unless you are building a system requiring minimal memory
403 bool "Kernel .config support"
405 This option enables the complete Linux kernel ".config" file
406 contents to be saved in the kernel. It provides documentation
407 of which kernel options are used in a running kernel or in an
408 on-disk kernel. This information can be extracted from the kernel
409 image file with the script scripts/extract-ikconfig and used as
410 input to rebuild the current kernel or to build another kernel.
411 It can also be extracted from a running kernel by reading
412 /proc/config.gz if enabled (below).
415 bool "Enable access to .config through /proc/config.gz"
416 depends on IKCONFIG && PROC_FS
418 This option enables access to the kernel configuration file
419 through /proc/config.gz.
425 This option enables panic() to be called when a system is out of
426 memory. This feature along with /proc/sys/kernel/panic allows a
427 different behavior on out-of-memory conditions when the standard
428 behavior (killing processes in an attempt to recover) does not
435 depends on !OOM_PANIC
439 bool "Configure standard kernel features (for small systems)"
441 This option allows certain base kernel options and settings
442 to be disabled or tweaked. This is for specialized
443 environments which can tolerate a "non-standard" kernel.
444 Only use this if you really know what you are doing.
447 bool "Enable delay accounting (EXPERIMENTAL)"
449 In addition to counting frequency the total delay in ns is also
450 recorded. CPU delays are specified as cpu-wait and cpu-run.
451 I/O delays are recorded for memory and regular I/O.
452 Information is accessible through /proc/<pid>/delay.
455 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
458 Say Y here to let the kernel print out symbolic crash information and
459 symbolic stack backtraces. This increases the size of the kernel
460 somewhat, as all symbols have to be loaded into the kernel image.
463 bool "Include all symbols in kallsyms"
464 depends on DEBUG_KERNEL && KALLSYMS
466 Normally kallsyms only contains the symbols of functions, for nicer
467 OOPS messages. Some debuggers can use kallsyms for other
468 symbols too: say Y here to include all symbols, and you
469 don't care about adding 300k to the size of your kernel.
473 config KALLSYMS_EXTRA_PASS
474 bool "Do an extra kallsyms pass"
477 If kallsyms is not working correctly, the build will fail with
478 inconsistent kallsyms data. If that occurs, log a bug report and
479 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
480 Always say N here unless you find a bug in kallsyms, which must be
481 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
482 you wait for kallsyms to be fixed.
485 bool "Enable futex support" if EMBEDDED
488 Disabling this option will cause the kernel to be built without
489 support for "fast userspace mutexes". The resulting kernel may not
490 run glibc-based applications correctly.
493 bool "Enable eventpoll support" if EMBEDDED
496 Disabling this option will cause the kernel to be built without
497 support for epoll family of system calls.
499 config CC_OPTIMIZE_FOR_SIZE
500 bool "Optimize for size"
501 default y if ARM || H8300
504 Enabling this option will pass "-Os" instead of "-O2" to gcc
505 resulting in a smaller kernel.
507 WARNING: some versions of gcc may generate incorrect code with this
508 option. If problems are observed, a gcc upgrade may be needed.
514 bool "Use full shmem filesystem" if EMBEDDED && MMU
516 The shmem is an internal filesystem used to manage shared memory.
517 It is backed by swap and manages resource limits. It is also exported
518 to userspace as tmpfs if TMPFS is enabled. Disabling this
519 option replaces shmem and tmpfs with the much simpler ramfs code,
520 which may be appropriate on small systems without swap.
522 config CC_ALIGN_FUNCTIONS
523 int "Function alignment" if EMBEDDED
526 Align the start of functions to the next power-of-two greater than n,
527 skipping up to n bytes. For instance, 32 aligns functions
528 to the next 32-byte boundary, but 24 would align to the next
529 32-byte boundary only if this can be done by skipping 23 bytes or less.
530 Zero means use compiler's default.
532 config CC_ALIGN_LABELS
533 int "Label alignment" if EMBEDDED
536 Align all branch targets to a power-of-two boundary, skipping
537 up to n bytes like ALIGN_FUNCTIONS. This option can easily
538 make code slower, because it must insert dummy operations for
539 when the branch target is reached in the usual flow of the code.
540 Zero means use compiler's default.
542 config CC_ALIGN_LOOPS
543 int "Loop alignment" if EMBEDDED
546 Align loops to a power-of-two boundary, skipping up to n bytes.
547 Zero means use compiler's default.
549 config CC_ALIGN_JUMPS
550 int "Jump alignment" if EMBEDDED
553 Align branch targets to a power-of-two boundary, for branch
554 targets where the targets can only be reached by jumping,
555 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
556 no dummy operations need be executed.
557 Zero means use compiler's default.
559 endmenu # General setup
565 menu "Loadable module support"
568 bool "Enable loadable module support"
570 Kernel modules are small pieces of compiled code which can
571 be inserted in the running kernel, rather than being
572 permanently built into the kernel. You use the "modprobe"
573 tool to add (and sometimes remove) them. If you say Y here,
574 many parts of the kernel can be built as modules (by
575 answering M instead of Y where indicated): this is most
576 useful for infrequently used options which are not required
577 for booting. For more information, see the man pages for
578 modprobe, lsmod, modinfo, insmod and rmmod.
580 If you say Y here, you will need to run "make
581 modules_install" to put the modules under /lib/modules/
582 where modprobe can find them (you may need to be root to do
588 bool "Module unloading"
591 Without this option you will not be able to unload any
592 modules (note that some modules may not be unloadable
593 anyway), which makes your kernel slightly smaller and
594 simpler. If unsure, say Y.
596 config MODULE_FORCE_UNLOAD
597 bool "Forced module unloading"
598 depends on MODULE_UNLOAD && EXPERIMENTAL
600 This option allows you to force a module to unload, even if the
601 kernel believes it is unsafe: the kernel will remove the module
602 without waiting for anyone to stop using it (using the -f option to
603 rmmod). This is mainly for kernel developers and desperate users.
606 config OBSOLETE_MODPARM
611 You need this option to use module parameters on modules which
612 have not been converted to the new module parameter system yet.
616 bool "Module versioning support (EXPERIMENTAL)"
617 depends on MODULES && EXPERIMENTAL
619 Usually, you have to use modules compiled with your kernel.
620 Saying Y here makes it sometimes possible to use modules
621 compiled for different kernels, by adding enough information
622 to the modules to (hopefully) spot any changes which would
623 make them incompatible with the kernel you are running. If
626 config MODULE_SRCVERSION_ALL
627 bool "Source checksum for all modules"
630 Modules which contain a MODULE_VERSION get an extra "srcversion"
631 field inserted into their modinfo section, which contains a
632 sum of the source files which made it. This helps maintainers
633 see exactly which source was used to build a module (since
634 others sometimes change the module source without updating
635 the version). With this option, such a "srcversion" field
636 will be created for all modules. If unsure, say N.
639 bool "Module signature verification (EXPERIMENTAL)"
640 depends on MODULES && EXPERIMENTAL
643 select CRYPTO_SIGNATURE
645 Check modules for valid signatures upon load.
647 config MODULE_SIG_FORCE
648 bool "Required modules to be validly signed (EXPERIMENTAL)"
649 depends on MODULE_SIG
651 Reject unsigned modules or signed modules for which we don't have a
655 bool "Automatic kernel module loading"
658 Normally when you have selected some parts of the kernel to
659 be created as kernel modules, you must load them (using the
660 "modprobe" command) before you can use them. If you say Y
661 here, some parts of the kernel will be able to load modules
662 automatically: when a part of the kernel needs a module, it
663 runs modprobe with the appropriate arguments, thereby
664 loading the module if it is available. If unsure, say Y.
669 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
671 Need stop_machine() primitive.