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24 drivers that have been replaced by something else, and/or are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.
93 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
94 you'll need to say Y here.
96 You can find documentation about IPC with "info ipc" and also in
97 section 6.4 of the Linux Programmer's Guide, available from
98 <http://www.tldp.org/guides.html>.
101 bool "POSIX Message Queues"
102 depends on NET && EXPERIMENTAL
104 POSIX variant of message queues is a part of IPC. In POSIX message
105 queues every message has a priority which decides about succession
106 of receiving it by a process. If you want to compile and run
107 programs written e.g. for Solaris with use of its POSIX message
108 queues (functions mq_*) say Y here. To use this feature you will
109 also need mqueue library, available from
110 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
112 POSIX message queues are visible as a filesystem called 'mqueue'
113 and can be mounted somewhere if you want to do filesystem
114 operations on message queues.
118 config BSD_PROCESS_ACCT
119 bool "BSD Process Accounting"
121 If you say Y here, a user level program will be able to instruct the
122 kernel (via a special system call) to write process accounting
123 information to a file: whenever a process exits, information about
124 that process will be appended to the file by the kernel. The
125 information includes things such as creation time, owning user,
126 command name, memory usage, controlling terminal etc. (the complete
127 list is in the struct acct in <file:include/linux/acct.h>). It is
128 up to the user level program to do useful things with this
129 information. This is generally a good idea, so say Y.
131 config BSD_PROCESS_ACCT_V3
132 bool "BSD Process Accounting version 3 file format"
133 depends on BSD_PROCESS_ACCT
136 If you say Y here, the process accounting information is written
137 in a new file format that also logs the process IDs of each
138 process and it's parent. Note that this file format is incompatible
139 with previous v0/v1/v2 file formats, so you will need updated tools
140 for processing it. A preliminary version of these tools is available
141 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
143 menu "Class Based Kernel Resource Management"
146 bool "Class Based Kernel Resource Management Core"
147 depends on EXPERIMENTAL
149 Class-based Kernel Resource Management is a framework for controlling
150 and monitoring resource allocation of user-defined groups of tasks or
151 incoming socket connections. For more information, please visit
154 If you say Y here, enable the Resource Class File System and atleast
155 one of the resource controllers below. Say N if you are unsure.
158 tristate "Resource Class File System (User API)"
161 RCFS is the filesystem API for CKRM. This separate configuration
162 option is provided only for debugging and will eventually disappear
163 since rcfs will be automounted whenever CKRM is configured.
165 Say N if unsure, Y if you've enabled CKRM, M to debug rcfs
168 config CKRM_TYPE_TASKCLASS
169 bool "Class Manager for Task Groups"
172 TASKCLASS provides the extensions for CKRM to track task classes
173 This is the base to enable task class based resource control for
174 cpu, memory and disk I/O.
178 config CKRM_RES_NUMTASKS
179 tristate "Number of Tasks Resource Manager"
180 depends on CKRM_TYPE_TASKCLASS
183 Provides a Resource Controller for CKRM that allows limiting no of
184 tasks a task class can have.
186 Say N if unsure, Y to use the feature.
188 config CKRM_CPU_SCHEDULE
189 bool "CKRM CPU scheduler"
190 depends on CKRM_TYPE_TASKCLASS
193 Use CKRM CPU scheduler instead of Linux Scheduler
195 Say N if unsure, Y to use the feature.
197 config CKRM_RES_BLKIO
198 tristate " Disk I/O Resource Controller"
199 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
202 Provides a resource controller for best-effort block I/O
203 bandwidth control. The controller attempts this by proportional
204 servicing of requests in the I/O scheduler. However, seek
205 optimizations and reordering by device drivers/disk controllers may
206 alter the actual bandwidth delivered to a class.
208 Say N if unsure, Y to use the feature.
211 bool "Class based physical memory controller"
215 Provide the basic support for collecting physical memory usage information
216 among classes. Say Y if you want to know the memory usage of each class.
218 config CKRM_MEM_LRUORDER_CHANGE
219 bool "Change the LRU ordering of scanned pages"
221 depends on CKRM_RES_MEM
223 While trying to free pages, by default(n), scanned pages are left were they
224 are found if they belong to relatively under-used class. In this case the
225 LRU ordering of the memory subsystemis left intact. If this option is chosen,
226 then the scanned pages are moved to the tail of the list(active or inactive).
227 Changing this to yes reduces the checking overhead but violates the approximate
228 LRU order that is maintained by the paging subsystem.
230 config CKRM_CPU_SCHEDULE_AT_BOOT
231 bool "Turn on at boot time"
232 depends on CKRM_CPU_SCHEDULE
235 Enable CKRM CPU Scheduler at boot time. Otherwise
236 it can be turned on dynamically at runtime. If not
237 turned on the default Linux Scheduler behavior
240 Say N if unsure, Y to use this feature
242 config CKRM_TYPE_SOCKETCLASS
243 bool "Class Manager for socket groups"
246 SOCKET provides the extensions for CKRM to track per socket
247 classes. This is the base to enable socket based resource
248 control for inbound connection control, bandwidth control etc.
252 config CKRM_RES_LISTENAQ
253 tristate "Multiple Accept Queues Resource Manager"
254 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
257 Provides a resource controller for CKRM to prioritize inbound
258 connection requests. See inbound control description for
259 "IP: TCP Multiple accept queues support". If you choose that
260 option choose this option to control the queue weights.
265 tristate "Vanilla Rule-based Classification Engine (RBCE)"
266 depends on CKRM && RCFS_FS
269 Provides an optional module to support creation of rules for automatic
270 classification of kernel objects. Rules are created/deleted/modified
271 through an rcfs interface. RBCE is not required for CKRM.
276 tristate "Enhanced Rule-based Classification Engine (RBCE)"
277 depends on CKRM && RCFS_FS && RELAYFS_FS && DELAY_ACCT
280 Provides an optional module to support creation of rules for automatic
281 classification of kernel objects, just like RBCE above. In addition,
282 CRBCE provides per-process delay data (requires DELAY_ACCT configured)
283 enabled) and makes information on significant kernel events available
284 to userspace tools through relayfs (requires RELAYFS_FS configured).
291 bool "Sysctl support"
293 The sysctl interface provides a means of dynamically changing
294 certain kernel parameters and variables on the fly without requiring
295 a recompile of the kernel or reboot of the system. The primary
296 interface consists of a system call, but if you say Y to "/proc
297 file system support", a tree of modifiable sysctl entries will be
298 generated beneath the /proc/sys directory. They are explained in the
299 files in <file:Documentation/sysctl/>. Note that enabling this
300 option will enlarge the kernel by at least 8 KB.
302 As it is generally a good thing, you should say Y here unless
303 building a kernel for install/rescue disks or your system is very
307 bool "Auditing support"
308 default y if SECURITY_SELINUX
311 Enable auditing infrastructure that can be used with another
312 kernel subsystem, such as SELinux (which requires this for
313 logging of avc messages output). Does not do system-call
314 auditing without CONFIG_AUDITSYSCALL.
317 bool "Enable system-call auditing support"
318 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
319 default y if SECURITY_SELINUX
322 Enable low-overhead system-call auditing infrastructure that
323 can be used independently or with another kernel subsystem,
327 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
329 default 17 if ARCH_S390
330 default 16 if X86_NUMAQ || IA64
334 Select kernel log buffer size as a power of 2.
335 Defaults and Examples:
336 17 => 128 KB for S/390
337 16 => 64 KB for x86 NUMAQ or IA-64
339 14 => 16 KB for uniprocessor
344 bool "Support for hot-pluggable devices" if !ARCH_S390
347 Say Y here if you want to plug devices into your computer while
348 the system is running, and be able to use them quickly. In many
349 cases, the devices can likewise be unplugged at any time too.
351 One well known example of this is PCMCIA- or PC-cards, credit-card
352 size devices such as network cards, modems or hard drives which are
353 plugged into slots found on all modern laptop computers. Another
354 example, used on modern desktops as well as laptops, is USB.
356 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
357 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
358 Then your kernel will automatically call out to a user mode "policy
359 agent" (/sbin/hotplug) to load modules and set up software needed
360 to use devices as you hotplug them.
362 config KOBJECT_UEVENT
363 bool "Kernel Userspace Events"
367 This option enables the kernel userspace event layer, which is a
368 simple mechanism for kernel-to-user communication over a netlink
370 The goal of the kernel userspace events layer is to provide a simple
371 and efficient events system, that notifies userspace about kobject
372 state changes. This will enable applications to just listen for
373 events instead of polling system devices and files.
374 Hotplug events (kobject addition and removal) are also available on
375 the netlink socket in addition to the execution of /sbin/hotplug if
376 CONFIG_HOTPLUG is enabled.
378 Say Y, unless you are building a system requiring minimal memory
382 bool "Kernel .config support"
384 This option enables the complete Linux kernel ".config" file
385 contents to be saved in the kernel. It provides documentation
386 of which kernel options are used in a running kernel or in an
387 on-disk kernel. This information can be extracted from the kernel
388 image file with the script scripts/extract-ikconfig and used as
389 input to rebuild the current kernel or to build another kernel.
390 It can also be extracted from a running kernel by reading
391 /proc/config.gz if enabled (below).
394 bool "Enable access to .config through /proc/config.gz"
395 depends on IKCONFIG && PROC_FS
397 This option enables access to the kernel configuration file
398 through /proc/config.gz.
404 This option enables panic() to be called when a system is out of
405 memory. This feature along with /proc/sys/kernel/panic allows a
406 different behavior on out-of-memory conditions when the standard
407 behavior (killing processes in an attempt to recover) does not
414 depends on !OOM_PANIC
418 bool "Configure standard kernel features (for small systems)"
420 This option allows certain base kernel options and settings
421 to be disabled or tweaked. This is for specialized
422 environments which can tolerate a "non-standard" kernel.
423 Only use this if you really know what you are doing.
426 bool "Enable delay accounting (EXPERIMENTAL)"
428 In addition to counting frequency the total delay in ns is also
429 recorded. CPU delays are specified as cpu-wait and cpu-run.
430 I/O delays are recorded for memory and regular I/O.
431 Information is accessible through /proc/<pid>/delay.
435 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
438 Say Y here to let the kernel print out symbolic crash information and
439 symbolic stack backtraces. This increases the size of the kernel
440 somewhat, as all symbols have to be loaded into the kernel image.
443 bool "Include all symbols in kallsyms"
444 depends on DEBUG_KERNEL && KALLSYMS
446 Normally kallsyms only contains the symbols of functions, for nicer
447 OOPS messages. Some debuggers can use kallsyms for other
448 symbols too: say Y here to include all symbols, and you
449 don't care about adding 300k to the size of your kernel.
453 config KALLSYMS_EXTRA_PASS
454 bool "Do an extra kallsyms pass"
457 If kallsyms is not working correctly, the build will fail with
458 inconsistent kallsyms data. If that occurs, log a bug report and
459 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
460 Always say N here unless you find a bug in kallsyms, which must be
461 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
462 you wait for kallsyms to be fixed.
465 bool "Enable futex support" if EMBEDDED
468 Disabling this option will cause the kernel to be built without
469 support for "fast userspace mutexes". The resulting kernel may not
470 run glibc-based applications correctly.
473 bool "Enable eventpoll support" if EMBEDDED
476 Disabling this option will cause the kernel to be built without
477 support for epoll family of system calls.
479 config CC_OPTIMIZE_FOR_SIZE
480 bool "Optimize for size"
481 default y if ARM || H8300
484 Enabling this option will pass "-Os" instead of "-O2" to gcc
485 resulting in a smaller kernel.
487 WARNING: some versions of gcc may generate incorrect code with this
488 option. If problems are observed, a gcc upgrade may be needed.
494 bool "Use full shmem filesystem" if EMBEDDED && MMU
496 The shmem is an internal filesystem used to manage shared memory.
497 It is backed by swap and manages resource limits. It is also exported
498 to userspace as tmpfs if TMPFS is enabled. Disabling this
499 option replaces shmem and tmpfs with the much simpler ramfs code,
500 which may be appropriate on small systems without swap.
502 config CC_ALIGN_FUNCTIONS
503 int "Function alignment" if EMBEDDED
506 Align the start of functions to the next power-of-two greater than n,
507 skipping up to n bytes. For instance, 32 aligns functions
508 to the next 32-byte boundary, but 24 would align to the next
509 32-byte boundary only if this can be done by skipping 23 bytes or less.
510 Zero means use compiler's default.
512 config CC_ALIGN_LABELS
513 int "Label alignment" if EMBEDDED
516 Align all branch targets to a power-of-two boundary, skipping
517 up to n bytes like ALIGN_FUNCTIONS. This option can easily
518 make code slower, because it must insert dummy operations for
519 when the branch target is reached in the usual flow of the code.
520 Zero means use compiler's default.
522 config CC_ALIGN_LOOPS
523 int "Loop alignment" if EMBEDDED
526 Align loops to a power-of-two boundary, skipping up to n bytes.
527 Zero means use compiler's default.
529 config CC_ALIGN_JUMPS
530 int "Jump alignment" if EMBEDDED
533 Align branch targets to a power-of-two boundary, for branch
534 targets where the targets can only be reached by jumping,
535 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
536 no dummy operations need be executed.
537 Zero means use compiler's default.
539 endmenu # General setup
545 menu "Loadable module support"
548 bool "Enable loadable module support"
550 Kernel modules are small pieces of compiled code which can
551 be inserted in the running kernel, rather than being
552 permanently built into the kernel. You use the "modprobe"
553 tool to add (and sometimes remove) them. If you say Y here,
554 many parts of the kernel can be built as modules (by
555 answering M instead of Y where indicated): this is most
556 useful for infrequently used options which are not required
557 for booting. For more information, see the man pages for
558 modprobe, lsmod, modinfo, insmod and rmmod.
560 If you say Y here, you will need to run "make
561 modules_install" to put the modules under /lib/modules/
562 where modprobe can find them (you may need to be root to do
568 bool "Module unloading"
571 Without this option you will not be able to unload any
572 modules (note that some modules may not be unloadable
573 anyway), which makes your kernel slightly smaller and
574 simpler. If unsure, say Y.
576 config MODULE_FORCE_UNLOAD
577 bool "Forced module unloading"
578 depends on MODULE_UNLOAD && EXPERIMENTAL
580 This option allows you to force a module to unload, even if the
581 kernel believes it is unsafe: the kernel will remove the module
582 without waiting for anyone to stop using it (using the -f option to
583 rmmod). This is mainly for kernel developers and desperate users.
586 config OBSOLETE_MODPARM
591 You need this option to use module parameters on modules which
592 have not been converted to the new module parameter system yet.
596 bool "Module versioning support (EXPERIMENTAL)"
597 depends on MODULES && EXPERIMENTAL
599 Usually, you have to use modules compiled with your kernel.
600 Saying Y here makes it sometimes possible to use modules
601 compiled for different kernels, by adding enough information
602 to the modules to (hopefully) spot any changes which would
603 make them incompatible with the kernel you are running. If
606 config MODULE_SRCVERSION_ALL
607 bool "Source checksum for all modules"
610 Modules which contain a MODULE_VERSION get an extra "srcversion"
611 field inserted into their modinfo section, which contains a
612 sum of the source files which made it. This helps maintainers
613 see exactly which source was used to build a module (since
614 others sometimes change the module source without updating
615 the version). With this option, such a "srcversion" field
616 will be created for all modules. If unsure, say N.
619 bool "Module signature verification (EXPERIMENTAL)"
620 depends on MODULES && EXPERIMENTAL
623 select CRYPTO_SIGNATURE
625 Check modules for valid signatures upon load.
627 config MODULE_SIG_FORCE
628 bool "Required modules to be validly signed (EXPERIMENTAL)"
629 depends on MODULE_SIG
631 Reject unsigned modules or signed modules for which we don't have a
635 bool "Automatic kernel module loading"
638 Normally when you have selected some parts of the kernel to
639 be created as kernel modules, you must load them (using the
640 "modprobe" command) before you can use them. If you say Y
641 here, some parts of the kernel will be able to load modules
642 automatically: when a part of the kernel needs a module, it
643 runs modprobe with the appropriate arguments, thereby
644 loading the module if it is available. If unsure, say Y.
649 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
651 Need stop_machine() primitive.