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24 drivers that have been replaced by something else, and/or are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
181 Provides a Null Resource Controller for CKRM that is purely for
182 demonstration purposes.
184 Say N if unsure, Y to use the feature.
187 config CKRM_RES_NUMTASKS
188 tristate "Number of Tasks Resource Manager"
189 depends on CKRM_TYPE_TASKCLASS
192 Provides a Resource Controller for CKRM that allows limiting no of
193 tasks a task class can have.
195 Say N if unsure, Y to use the feature.
197 config CKRM_CPU_SCHEDULE
198 bool "CKRM CPU scheduler"
199 depends on CKRM_TYPE_TASKCLASS
202 Use CKRM CPU scheduler instead of Linux Scheduler
204 Say N if unsure, Y to use the feature.
206 config CKRM_RES_BLKIO
207 tristate " Disk I/O Resource Controller"
208 depends on CKRM_TYPE_TASKCLASS && IOSCHED_CFQ
211 Provides a resource controller for best-effort block I/O
212 bandwidth control. The controller attempts this by proportional
213 servicing of requests in the I/O scheduler. However, seek
214 optimizations and reordering by device drivers/disk controllers may
215 alter the actual bandwidth delivered to a class.
217 Say N if unsure, Y to use the feature.
220 bool "Class based physical memory controller"
224 Provide the basic support for collecting physical memory usage information
225 among classes. Say Y if you want to know the memory usage of each class.
227 config CKRM_MEM_LRUORDER_CHANGE
228 bool "Change the LRU ordering of scanned pages"
230 depends on CKRM_RES_MEM
232 While trying to free pages, by default(n), scanned pages are left were they
233 are found if they belong to relatively under-used class. In this case the
234 LRU ordering of the memory subsystemis left intact. If this option is chosen,
235 then the scanned pages are moved to the tail of the list(active or inactive).
236 Changing this to yes reduces the checking overhead but violates the approximate
237 LRU order that is maintained by the paging subsystem.
239 config CKRM_CPU_SCHEDULE_AT_BOOT
240 bool "Turn on at boot time"
241 depends on CKRM_CPU_SCHEDULE
244 Enable CKRM CPU Scheduler at boot time. Otherwise
245 it can be turned on dynamically at runtime. If not
246 turned on the default Linux Scheduler behavior
249 Say N if unsure, Y to use this feature
251 config CKRM_TYPE_SOCKETCLASS
252 bool "Class Manager for socket groups"
255 SOCKET provides the extensions for CKRM to track per socket
256 classes. This is the base to enable socket based resource
257 control for inbound connection control, bandwidth control etc.
261 config CKRM_RES_LISTENAQ
262 tristate "Multiple Accept Queues Resource Manager"
263 depends on CKRM_TYPE_SOCKETCLASS && ACCEPT_QUEUES
266 Provides a resource controller for CKRM to prioritize inbound
267 connection requests. See inbound control description for
268 "IP: TCP Multiple accept queues support". If you choose that
269 option choose this option to control the queue weights.
274 prompt "Classification Engine"
275 depends on CKRM && RCFS_FS
278 Select a classification engine (CE) that assists in
279 automatic classification of kernel objects managed by CKRM when
280 they are created. Without a CE, a user must manually
281 classify objects into classes. Processes inherit their parent's
284 Only one engine can be built into the kernel though all can be
285 built as modules (only one will load).
290 tristate "Vanilla RBCE"
292 Vanilla Rule-based Classification Engine (RBCE). Rules for
293 classifying kernel objects are created/deleted/modified through
294 a RCFS directory using a filesystem interface.
296 Any CE is optional. If unsure, say N.
299 tristate "Enhanced RBCE"
300 depends on DELAY_ACCT && RELAYFS_FS
302 Enhanced Rule-based Classification Engine (CRBCE). Like the Vanilla
303 RBCE, rules for classifying kernel objects are created, deleted and
304 modified through a RCFS directory using a filesystem interface
305 (requires CKRM_RCFS configured).
307 In addition, CRBCE provides per-process delay data
308 (requires DELAY_ACCT configured) and makes information on significant
309 kernel events available to userspace tools through relayfs
310 (requires RELAYFS_FS configured).
312 Any CE is optional. If unsure, say N.
319 bool "Sysctl support"
321 The sysctl interface provides a means of dynamically changing
322 certain kernel parameters and variables on the fly without requiring
323 a recompile of the kernel or reboot of the system. The primary
324 interface consists of a system call, but if you say Y to "/proc
325 file system support", a tree of modifiable sysctl entries will be
326 generated beneath the /proc/sys directory. They are explained in the
327 files in <file:Documentation/sysctl/>. Note that enabling this
328 option will enlarge the kernel by at least 8 KB.
330 As it is generally a good thing, you should say Y here unless
331 building a kernel for install/rescue disks or your system is very
335 bool "Auditing support"
336 default y if SECURITY_SELINUX
339 Enable auditing infrastructure that can be used with another
340 kernel subsystem, such as SELinux (which requires this for
341 logging of avc messages output). Does not do system-call
342 auditing without CONFIG_AUDITSYSCALL.
345 bool "Enable system-call auditing support"
346 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
347 default y if SECURITY_SELINUX
350 Enable low-overhead system-call auditing infrastructure that
351 can be used independently or with another kernel subsystem,
355 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
357 default 17 if ARCH_S390
358 default 16 if X86_NUMAQ || IA64
362 Select kernel log buffer size as a power of 2.
363 Defaults and Examples:
364 17 => 128 KB for S/390
365 16 => 64 KB for x86 NUMAQ or IA-64
367 14 => 16 KB for uniprocessor
372 bool "Support for hot-pluggable devices" if !ARCH_S390
375 Say Y here if you want to plug devices into your computer while
376 the system is running, and be able to use them quickly. In many
377 cases, the devices can likewise be unplugged at any time too.
379 One well known example of this is PCMCIA- or PC-cards, credit-card
380 size devices such as network cards, modems or hard drives which are
381 plugged into slots found on all modern laptop computers. Another
382 example, used on modern desktops as well as laptops, is USB.
384 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
385 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
386 Then your kernel will automatically call out to a user mode "policy
387 agent" (/sbin/hotplug) to load modules and set up software needed
388 to use devices as you hotplug them.
390 config KOBJECT_UEVENT
391 bool "Kernel Userspace Events"
395 This option enables the kernel userspace event layer, which is a
396 simple mechanism for kernel-to-user communication over a netlink
398 The goal of the kernel userspace events layer is to provide a simple
399 and efficient events system, that notifies userspace about kobject
400 state changes. This will enable applications to just listen for
401 events instead of polling system devices and files.
402 Hotplug events (kobject addition and removal) are also available on
403 the netlink socket in addition to the execution of /sbin/hotplug if
404 CONFIG_HOTPLUG is enabled.
406 Say Y, unless you are building a system requiring minimal memory
410 bool "Kernel .config support"
412 This option enables the complete Linux kernel ".config" file
413 contents to be saved in the kernel. It provides documentation
414 of which kernel options are used in a running kernel or in an
415 on-disk kernel. This information can be extracted from the kernel
416 image file with the script scripts/extract-ikconfig and used as
417 input to rebuild the current kernel or to build another kernel.
418 It can also be extracted from a running kernel by reading
419 /proc/config.gz if enabled (below).
422 bool "Enable access to .config through /proc/config.gz"
423 depends on IKCONFIG && PROC_FS
425 This option enables access to the kernel configuration file
426 through /proc/config.gz.
432 This option enables panic() to be called when a system is out of
433 memory. This feature along with /proc/sys/kernel/panic allows a
434 different behavior on out-of-memory conditions when the standard
435 behavior (killing processes in an attempt to recover) does not
442 depends on !OOM_PANIC
446 bool "Configure standard kernel features (for small systems)"
448 This option allows certain base kernel options and settings
449 to be disabled or tweaked. This is for specialized
450 environments which can tolerate a "non-standard" kernel.
451 Only use this if you really know what you are doing.
454 bool "Enable delay accounting (EXPERIMENTAL)"
456 In addition to counting frequency the total delay in ns is also
457 recorded. CPU delays are specified as cpu-wait and cpu-run.
458 I/O delays are recorded for memory and regular I/O.
459 Information is accessible through /proc/<pid>/delay.
462 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
465 Say Y here to let the kernel print out symbolic crash information and
466 symbolic stack backtraces. This increases the size of the kernel
467 somewhat, as all symbols have to be loaded into the kernel image.
470 bool "Include all symbols in kallsyms"
471 depends on DEBUG_KERNEL && KALLSYMS
473 Normally kallsyms only contains the symbols of functions, for nicer
474 OOPS messages. Some debuggers can use kallsyms for other
475 symbols too: say Y here to include all symbols, and you
476 don't care about adding 300k to the size of your kernel.
480 config KALLSYMS_EXTRA_PASS
481 bool "Do an extra kallsyms pass"
484 If kallsyms is not working correctly, the build will fail with
485 inconsistent kallsyms data. If that occurs, log a bug report and
486 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
487 Always say N here unless you find a bug in kallsyms, which must be
488 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
489 you wait for kallsyms to be fixed.
492 bool "Enable futex support" if EMBEDDED
495 Disabling this option will cause the kernel to be built without
496 support for "fast userspace mutexes". The resulting kernel may not
497 run glibc-based applications correctly.
500 bool "Enable eventpoll support" if EMBEDDED
503 Disabling this option will cause the kernel to be built without
504 support for epoll family of system calls.
506 config CC_OPTIMIZE_FOR_SIZE
507 bool "Optimize for size"
508 default y if ARM || H8300
511 Enabling this option will pass "-Os" instead of "-O2" to gcc
512 resulting in a smaller kernel.
514 WARNING: some versions of gcc may generate incorrect code with this
515 option. If problems are observed, a gcc upgrade may be needed.
521 bool "Use full shmem filesystem" if EMBEDDED && MMU
523 The shmem is an internal filesystem used to manage shared memory.
524 It is backed by swap and manages resource limits. It is also exported
525 to userspace as tmpfs if TMPFS is enabled. Disabling this
526 option replaces shmem and tmpfs with the much simpler ramfs code,
527 which may be appropriate on small systems without swap.
529 config CC_ALIGN_FUNCTIONS
530 int "Function alignment" if EMBEDDED
533 Align the start of functions to the next power-of-two greater than n,
534 skipping up to n bytes. For instance, 32 aligns functions
535 to the next 32-byte boundary, but 24 would align to the next
536 32-byte boundary only if this can be done by skipping 23 bytes or less.
537 Zero means use compiler's default.
539 config CC_ALIGN_LABELS
540 int "Label alignment" if EMBEDDED
543 Align all branch targets to a power-of-two boundary, skipping
544 up to n bytes like ALIGN_FUNCTIONS. This option can easily
545 make code slower, because it must insert dummy operations for
546 when the branch target is reached in the usual flow of the code.
547 Zero means use compiler's default.
549 config CC_ALIGN_LOOPS
550 int "Loop alignment" if EMBEDDED
553 Align loops to a power-of-two boundary, skipping up to n bytes.
554 Zero means use compiler's default.
556 config CC_ALIGN_JUMPS
557 int "Jump alignment" if EMBEDDED
560 Align branch targets to a power-of-two boundary, for branch
561 targets where the targets can only be reached by jumping,
562 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
563 no dummy operations need be executed.
564 Zero means use compiler's default.
566 endmenu # General setup
572 menu "Loadable module support"
575 bool "Enable loadable module support"
577 Kernel modules are small pieces of compiled code which can
578 be inserted in the running kernel, rather than being
579 permanently built into the kernel. You use the "modprobe"
580 tool to add (and sometimes remove) them. If you say Y here,
581 many parts of the kernel can be built as modules (by
582 answering M instead of Y where indicated): this is most
583 useful for infrequently used options which are not required
584 for booting. For more information, see the man pages for
585 modprobe, lsmod, modinfo, insmod and rmmod.
587 If you say Y here, you will need to run "make
588 modules_install" to put the modules under /lib/modules/
589 where modprobe can find them (you may need to be root to do
595 bool "Module unloading"
598 Without this option you will not be able to unload any
599 modules (note that some modules may not be unloadable
600 anyway), which makes your kernel slightly smaller and
601 simpler. If unsure, say Y.
603 config MODULE_FORCE_UNLOAD
604 bool "Forced module unloading"
605 depends on MODULE_UNLOAD && EXPERIMENTAL
607 This option allows you to force a module to unload, even if the
608 kernel believes it is unsafe: the kernel will remove the module
609 without waiting for anyone to stop using it (using the -f option to
610 rmmod). This is mainly for kernel developers and desperate users.
613 config OBSOLETE_MODPARM
618 You need this option to use module parameters on modules which
619 have not been converted to the new module parameter system yet.
623 bool "Module versioning support (EXPERIMENTAL)"
624 depends on MODULES && EXPERIMENTAL
626 Usually, you have to use modules compiled with your kernel.
627 Saying Y here makes it sometimes possible to use modules
628 compiled for different kernels, by adding enough information
629 to the modules to (hopefully) spot any changes which would
630 make them incompatible with the kernel you are running. If
633 config MODULE_SRCVERSION_ALL
634 bool "Source checksum for all modules"
637 Modules which contain a MODULE_VERSION get an extra "srcversion"
638 field inserted into their modinfo section, which contains a
639 sum of the source files which made it. This helps maintainers
640 see exactly which source was used to build a module (since
641 others sometimes change the module source without updating
642 the version). With this option, such a "srcversion" field
643 will be created for all modules. If unsure, say N.
646 bool "Module signature verification (EXPERIMENTAL)"
647 depends on MODULES && EXPERIMENTAL
650 select CRYPTO_SIGNATURE
652 Check modules for valid signatures upon load.
654 config MODULE_SIG_FORCE
655 bool "Required modules to be validly signed (EXPERIMENTAL)"
656 depends on MODULE_SIG
658 Reject unsigned modules or signed modules for which we don't have a
662 bool "Automatic kernel module loading"
665 Normally when you have selected some parts of the kernel to
666 be created as kernel modules, you must load them (using the
667 "modprobe" command) before you can use them. If you say Y
668 here, some parts of the kernel will be able to load modules
669 automatically: when a part of the kernel needs a module, it
670 runs modprobe with the appropriate arguments, thereby
671 loading the module if it is available. If unsure, say Y.
676 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
678 Need stop_machine() primitive.