init/Kconfig

   1 config DEFCONFIG_LIST
   2         string
   3         depends on !UML
   4         option defconfig_list
   5         default "/lib/modules/$UNAME_RELEASE/.config"
   6         default "/etc/kernel-config"
   7         default "/boot/config-$UNAME_RELEASE"
   8         default "arch/$ARCH/defconfig"
   9
  10 menu "General setup"
  11
  12 config EXPERIMENTAL
  13         bool "Prompt for development and/or incomplete code/drivers"
  14         ---help---
  15           Some of the various things that Linux supports (such as network
  16           drivers, file systems, network protocols, etc.) can be in a state
  17           of development where the functionality, stability, or the level of
  18           testing is not yet high enough for general use. This is usually
  19           known as the "alpha-test" phase among developers. If a feature is
  20           currently in alpha-test, then the developers usually discourage
  21           uninformed widespread use of this feature by the general public to
  22           avoid "Why doesn't this work?" type mail messages. However, active
  23           testing and use of these systems is welcomed. Just be aware that it
  24           may not meet the normal level of reliability or it may fail to work
  25           in some special cases. Detailed bug reports from people familiar
  26           with the kernel internals are usually welcomed by the developers
  27           (before submitting bug reports, please read the documents
  28           <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  29           <file:Documentation/BUG-HUNTING>, and
  30           <file:Documentation/oops-tracing.txt> in the kernel source).
  31
  32           This option will also make obsoleted drivers available. These are
  33           drivers that have been replaced by something else, and/or are
  34           scheduled to be removed in a future kernel release.
  35
  36           Unless you intend to help test and develop a feature or driver that
  37           falls into this category, or you have a situation that requires
  38           using these features, you should probably say N here, which will
  39           cause the configurator to present you with fewer choices. If
  40           you say Y here, you will be offered the choice of using features or
  41           drivers that are currently considered to be in the alpha-test phase.
  42
  43 config BROKEN
  44         bool
  45
  46 config BROKEN_ON_SMP
  47         bool
  48         depends on BROKEN || !SMP
  49         default y
  50
  51 config LOCK_KERNEL
  52         bool
  53         depends on SMP || PREEMPT
  54         default y
  55
  56 config INIT_ENV_ARG_LIMIT
  57         int
  58         default 32 if !UML
  59         default 128 if UML
  60         help
  61           Maximum of each of the number of arguments and environment
  62           variables passed to init from the kernel command line.
  63
  64
  65 config LOCALVERSION
  66         string "Local version - append to kernel release"
  67         help
  68           Append an extra string to the end of your kernel version.
  69           This will show up when you type uname, for example.
  70           The string you set here will be appended after the contents of
  71           any files with a filename matching localversion* in your
  72           object and source tree, in that order.  Your total string can
  73           be a maximum of 64 characters.
  74
  75 config LOCALVERSION_AUTO
  76         bool "Automatically append version information to the version string"
  77         default y
  78         help
  79           This will try to automatically determine if the current tree is a
  80           release tree by looking for git tags that belong to the current
  81           top of tree revision.
  82
  83           A string of the format -gxxxxxxxx will be added to the localversion
  84           if a git-based tree is found.  The string generated by this will be
  85           appended after any matching localversion* files, and after the value
  86           set in CONFIG_LOCALVERSION.
  87
  88           (The actual string used here is the first eight characters produced
  89           by running the command:
  90
  91             $ git rev-parse --verify HEAD
  92
  93           which is done within the script "scripts/setlocalversion".)
  94
  95 config SWAP
  96         bool "Support for paging of anonymous memory (swap)"
  97         depends on MMU && BLOCK
  98         default y
  99         help
 100           This option allows you to choose whether you want to have support
 101           for so called swap devices or swap files in your kernel that are
 102           used to provide more virtual memory than the actual RAM present
 103           in your computer.  If unsure say Y.
 104
 105 config SYSVIPC
 106         bool "System V IPC"
 107         ---help---
 108           Inter Process Communication is a suite of library functions and
 109           system calls which let processes (running programs) synchronize and
 110           exchange information. It is generally considered to be a good thing,
 111           and some programs won't run unless you say Y here. In particular, if
 112           you want to run the DOS emulator dosemu under Linux (read the
 113           DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 114           you'll need to say Y here.
 115
 116           You can find documentation about IPC with "info ipc" and also in
 117           section 6.4 of the Linux Programmer's Guide, available from
 118           <http://www.tldp.org/guides.html>.
 119
 120 config SYSVIPC_SYSCTL
 121         bool
 122         depends on SYSVIPC
 123         depends on SYSCTL
 124         default y
 125
 126 config POSIX_MQUEUE
 127         bool "POSIX Message Queues"
 128         depends on NET && EXPERIMENTAL
 129         ---help---
 130           POSIX variant of message queues is a part of IPC. In POSIX message
 131           queues every message has a priority which decides about succession
 132           of receiving it by a process. If you want to compile and run
 133           programs written e.g. for Solaris with use of its POSIX message
 134           queues (functions mq_*) say Y here.
 135
 136           POSIX message queues are visible as a filesystem called 'mqueue'
 137           and can be mounted somewhere if you want to do filesystem
 138           operations on message queues.
 139
 140           If unsure, say Y.
 141
 142 config BSD_PROCESS_ACCT
 143         bool "BSD Process Accounting"
 144         help
 145           If you say Y here, a user level program will be able to instruct the
 146           kernel (via a special system call) to write process accounting
 147           information to a file: whenever a process exits, information about
 148           that process will be appended to the file by the kernel.  The
 149           information includes things such as creation time, owning user,
 150           command name, memory usage, controlling terminal etc. (the complete
 151           list is in the struct acct in <file:include/linux/acct.h>).  It is
 152           up to the user level program to do useful things with this
 153           information.  This is generally a good idea, so say Y.
 154
 155 config BSD_PROCESS_ACCT_V3
 156         bool "BSD Process Accounting version 3 file format"
 157         depends on BSD_PROCESS_ACCT
 158         default n
 159         help
 160           If you say Y here, the process accounting information is written
 161           in a new file format that also logs the process IDs of each
 162           process and it's parent. Note that this file format is incompatible
 163           with previous v0/v1/v2 file formats, so you will need updated tools
 164           for processing it. A preliminary version of these tools is available
 165           at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
 166
 167 config TASKSTATS
 168         bool "Export task/process statistics through netlink (EXPERIMENTAL)"
 169         depends on NET
 170         default n
 171         help
 172           Export selected statistics for tasks/processes through the
 173           generic netlink interface. Unlike BSD process accounting, the
 174           statistics are available during the lifetime of tasks/processes as
 175           responses to commands. Like BSD accounting, they are sent to user
 176           space on task exit.
 177
 178           Say N if unsure.
 179
 180 config TASK_DELAY_ACCT
 181         bool "Enable per-task delay accounting (EXPERIMENTAL)"
 182         depends on TASKSTATS
 183         help
 184           Collect information on time spent by a task waiting for system
 185           resources like cpu, synchronous block I/O completion and swapping
 186           in pages. Such statistics can help in setting a task's priorities
 187           relative to other tasks for cpu, io, rss limits etc.
 188
 189           Say N if unsure.
 190
 191 config TASK_XACCT
 192         bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
 193         depends on TASKSTATS
 194         help
 195           Collect extended task accounting data and send the data
 196           to userland for processing over the taskstats interface.
 197
 198           Say N if unsure.
 199
 200 config TASK_IO_ACCOUNTING
 201         bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
 202         depends on TASK_XACCT
 203         help
 204           Collect information on the number of bytes of storage I/O which this
 205           task has caused.
 206
 207           Say N if unsure.
 208
 209 config USER_NS
 210         bool "User Namespaces (EXPERIMENTAL)"
 211         default n
 212         depends on EXPERIMENTAL
 213         help
 214           Support user namespaces.  This allows containers, i.e.
 215           vservers, to use user namespaces to provide different
 216           user info for different servers.  If unsure, say N.
 217
 218 config AUDIT
 219         bool "Auditing support"
 220         depends on NET
 221         help
 222           Enable auditing infrastructure that can be used with another
 223           kernel subsystem, such as SELinux (which requires this for
 224           logging of avc messages output).  Does not do system-call
 225           auditing without CONFIG_AUDITSYSCALL.
 226
 227 config AUDITSYSCALL
 228         bool "Enable system-call auditing support"
 229         depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
 230         default y if SECURITY_SELINUX
 231         help
 232           Enable low-overhead system-call auditing infrastructure that
 233           can be used independently or with another kernel subsystem,
 234           such as SELinux.  To use audit's filesystem watch feature, please
 235           ensure that INOTIFY is configured.
 236
 237 config AUDIT_TREE
 238         def_bool y
 239         depends on AUDITSYSCALL && INOTIFY
 240
 241 config IKCONFIG
 242         tristate "Kernel .config support"
 243         ---help---
 244           This option enables the complete Linux kernel ".config" file
 245           contents to be saved in the kernel. It provides documentation
 246           of which kernel options are used in a running kernel or in an
 247           on-disk kernel.  This information can be extracted from the kernel
 248           image file with the script scripts/extract-ikconfig and used as
 249           input to rebuild the current kernel or to build another kernel.
 250           It can also be extracted from a running kernel by reading
 251           /proc/config.gz if enabled (below).
 252
 253 config IKCONFIG_PROC
 254         bool "Enable access to .config through /proc/config.gz"
 255         depends on IKCONFIG && PROC_FS
 256         ---help---
 257           This option enables access to the kernel configuration file
 258           through /proc/config.gz.
 259
 260 config LOG_BUF_SHIFT
 261         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 262         range 12 21
 263         default 17 if S390 || LOCKDEP
 264         default 16 if X86_NUMAQ || IA64
 265         default 15 if SMP
 266         default 14
 267         help
 268           Select kernel log buffer size as a power of 2.
 269           Defaults and Examples:
 270                      17 => 128 KB for S/390
 271                      16 => 64 KB for x86 NUMAQ or IA-64
 272                      15 => 32 KB for SMP
 273                      14 => 16 KB for uniprocessor
 274                      13 =>  8 KB
 275                      12 =>  4 KB
 276
 277 config CGROUPS
 278         bool "Control Group support"
 279         help
 280           This option will let you use process cgroup subsystems
 281           such as Cpusets
 282
 283           Say N if unsure.
 284
 285 config CGROUP_DEBUG
 286         bool "Example debug cgroup subsystem"
 287         depends on CGROUPS
 288         help
 289           This option enables a simple cgroup subsystem that
 290           exports useful debugging information about the cgroups
 291           framework
 292
 293           Say N if unsure
 294
 295 config CGROUP_NS
 296         bool "Namespace cgroup subsystem"
 297         depends on CGROUPS
 298         help
 299           Provides a simple namespace cgroup subsystem to
 300           provide hierarchical naming of sets of namespaces,
 301           for instance virtual servers and checkpoint/restart
 302           jobs.
 303
 304 config CGROUP_CPUACCT
 305         bool "Simple CPU accounting cgroup subsystem"
 306         depends on CGROUPS
 307         help
 308           Provides a simple Resource Controller for monitoring the
 309           total CPU consumed by the tasks in a cgroup
 310
 311 config CPUSETS
 312         bool "Cpuset support"
 313         depends on SMP && CGROUPS
 314         help
 315           This option will let you create and manage CPUSETs which
 316           allow dynamically partitioning a system into sets of CPUs and
 317           Memory Nodes and assigning tasks to run only within those sets.
 318           This is primarily useful on large SMP or NUMA systems.
 319
 320           Say N if unsure.
 321
 322 config FAIR_GROUP_SCHED
 323         bool "Fair group CPU scheduler"
 324         default y
 325         help
 326           This feature lets CPU scheduler recognize task groups and control CPU
 327           bandwidth allocation to such task groups.
 328
 329 choice
 330         depends on FAIR_GROUP_SCHED
 331         prompt "Basis for grouping tasks"
 332         default FAIR_USER_SCHED
 333
 334 config FAIR_USER_SCHED
 335         bool "user id"
 336         help
 337           This option will choose userid as the basis for grouping
 338           tasks, thus providing equal CPU bandwidth to each user.
 339
 340 config FAIR_CGROUP_SCHED
 341         bool "Control groups"
 342         depends on CGROUPS
 343         help
 344           This option allows you to create arbitrary task groups
 345           using the "cgroup" pseudo filesystem and control
 346           the cpu bandwidth allocated to each such task group.
 347           Refer to Documentation/cgroups.txt for more information
 348           on "cgroup" pseudo filesystem.
 349
 350 endchoice
 351
 352 config SYSFS_DEPRECATED
 353         bool "Create deprecated sysfs files"
 354         default y
 355         help
 356           This option creates deprecated symlinks such as the
 357           "device"-link, the <subsystem>:<name>-link, and the
 358           "bus"-link. It may also add deprecated key in the
 359           uevent environment.
 360           None of these features or values should be used today, as
 361           they export driver core implementation details to userspace
 362           or export properties which can't be kept stable across kernel
 363           releases.
 364
 365           If enabled, this option will also move any device structures
 366           that belong to a class, back into the /sys/class hierarchy, in
 367           order to support older versions of udev.
 368
 369           If you are using a distro that was released in 2006 or later,
 370           it should be safe to say N here.
 371
 372 config PROC_PID_CPUSET
 373         bool "Include legacy /proc/<pid>/cpuset file"
 374         depends on CPUSETS
 375         default y
 376
 377 config RELAY
 378         bool "Kernel->user space relay support (formerly relayfs)"
 379         help
 380           This option enables support for relay interface support in
 381           certain file systems (such as debugfs).
 382           It is designed to provide an efficient mechanism for tools and
 383           facilities to relay large amounts of data from kernel space to
 384           user space.
 385
 386           If unsure, say N.
 387
 388 config BLK_DEV_INITRD
 389         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 390         depends on BROKEN || !FRV
 391         help
 392           The initial RAM filesystem is a ramfs which is loaded by the
 393           boot loader (loadlin or lilo) and that is mounted as root
 394           before the normal boot procedure. It is typically used to
 395           load modules needed to mount the "real" root file system,
 396           etc. See <file:Documentation/initrd.txt> for details.
 397
 398           If RAM disk support (BLK_DEV_RAM) is also included, this
 399           also enables initial RAM disk (initrd) support and adds
 400           15 Kbytes (more on some other architectures) to the kernel size.
 401
 402           If unsure say Y.
 403
 404 if BLK_DEV_INITRD
 405
 406 source "usr/Kconfig"
 407
 408 endif
 409
 410 config CC_OPTIMIZE_FOR_SIZE
 411         bool "Optimize for size (Look out for broken compilers!)"
 412         default y
 413         depends on ARM || H8300 || SUPERH || EXPERIMENTAL
 414         help
 415           Enabling this option will pass "-Os" instead of "-O2" to gcc
 416           resulting in a smaller kernel.
 417
 418           WARNING: some versions of gcc may generate incorrect code with this
 419           option.  If problems are observed, a gcc upgrade may be needed.
 420
 421           If unsure, say N.
 422
 423 config SYSCTL
 424         bool
 425
 426 menuconfig EMBEDDED
 427         bool "Configure standard kernel features (for small systems)"
 428         help
 429           This option allows certain base kernel options and settings
 430           to be disabled or tweaked. This is for specialized
 431           environments which can tolerate a "non-standard" kernel.
 432           Only use this if you really know what you are doing.
 433
 434 config UID16
 435         bool "Enable 16-bit UID system calls" if EMBEDDED
 436         depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
 437         default y
 438         help
 439           This enables the legacy 16-bit UID syscall wrappers.
 440
 441 config SYSCTL_SYSCALL
 442         bool "Sysctl syscall support" if EMBEDDED
 443         default y
 444         select SYSCTL
 445         ---help---
 446           sys_sysctl uses binary paths that have been found challenging
 447           to properly maintain and use.  The interface in /proc/sys
 448           using paths with ascii names is now the primary path to this
 449           information.
 450
 451           Almost nothing using the binary sysctl interface so if you are
 452           trying to save some space it is probably safe to disable this,
 453           making your kernel marginally smaller.
 454
 455           If unsure say Y here.
 456
 457 config KALLSYMS
 458          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 459          default y
 460          help
 461            Say Y here to let the kernel print out symbolic crash information and
 462            symbolic stack backtraces. This increases the size of the kernel
 463            somewhat, as all symbols have to be loaded into the kernel image.
 464
 465 config KALLSYMS_ALL
 466         bool "Include all symbols in kallsyms"
 467         depends on DEBUG_KERNEL && KALLSYMS
 468         help
 469            Normally kallsyms only contains the symbols of functions, for nicer
 470            OOPS messages.  Some debuggers can use kallsyms for other
 471            symbols too: say Y here to include all symbols, if you need them
 472            and you don't care about adding 300k to the size of your kernel.
 473
 474            Say N.
 475
 476 config KALLSYMS_EXTRA_PASS
 477         bool "Do an extra kallsyms pass"
 478         depends on KALLSYMS
 479         help
 480            If kallsyms is not working correctly, the build will fail with
 481            inconsistent kallsyms data.  If that occurs, log a bug report and
 482            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 483            Always say N here unless you find a bug in kallsyms, which must be
 484            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 485            you wait for kallsyms to be fixed.
 486
 487
 488 config HOTPLUG
 489         bool "Support for hot-pluggable devices" if EMBEDDED
 490         default y
 491         help
 492           This option is provided for the case where no hotplug or uevent
 493           capabilities is wanted by the kernel.  You should only consider
 494           disabling this option for embedded systems that do not use modules, a
 495           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 496
 497 config PRINTK
 498         default y
 499         bool "Enable support for printk" if EMBEDDED
 500         help
 501           This option enables normal printk support. Removing it
 502           eliminates most of the message strings from the kernel image
 503           and makes the kernel more or less silent. As this makes it
 504           very difficult to diagnose system problems, saying N here is
 505           strongly discouraged.
 506
 507 config BUG
 508         bool "BUG() support" if EMBEDDED
 509         default y
 510         help
 511           Disabling this option eliminates support for BUG and WARN, reducing
 512           the size of your kernel image and potentially quietly ignoring
 513           numerous fatal conditions. You should only consider disabling this
 514           option for embedded systems with no facilities for reporting errors.
 515           Just say Y.
 516
 517 config ELF_CORE
 518         default y
 519         bool "Enable ELF core dumps" if EMBEDDED
 520         help
 521           Enable support for generating core dumps. Disabling saves about 4k.
 522
 523 config BASE_FULL
 524         default y
 525         bool "Enable full-sized data structures for core" if EMBEDDED
 526         help
 527           Disabling this option reduces the size of miscellaneous core
 528           kernel data structures. This saves memory on small machines,
 529           but may reduce performance.
 530
 531 config FUTEX
 532         bool "Enable futex support" if EMBEDDED
 533         default y
 534         select RT_MUTEXES
 535         help
 536           Disabling this option will cause the kernel to be built without
 537           support for "fast userspace mutexes".  The resulting kernel may not
 538           run glibc-based applications correctly.
 539
 540 config ANON_INODES
 541         bool
 542
 543 config EPOLL
 544         bool "Enable eventpoll support" if EMBEDDED
 545         default y
 546         select ANON_INODES
 547         help
 548           Disabling this option will cause the kernel to be built without
 549           support for epoll family of system calls.
 550
 551 config SIGNALFD
 552         bool "Enable signalfd() system call" if EMBEDDED
 553         select ANON_INODES
 554         default y
 555         help
 556           Enable the signalfd() system call that allows to receive signals
 557           on a file descriptor.
 558
 559           If unsure, say Y.
 560
 561 config TIMERFD
 562         bool "Enable timerfd() system call" if EMBEDDED
 563         select ANON_INODES
 564         depends on BROKEN
 565         default y
 566         help
 567           Enable the timerfd() system call that allows to receive timer
 568           events on a file descriptor.
 569
 570           If unsure, say Y.
 571
 572 config EVENTFD
 573         bool "Enable eventfd() system call" if EMBEDDED
 574         select ANON_INODES
 575         default y
 576         help
 577           Enable the eventfd() system call that allows to receive both
 578           kernel notification (ie. KAIO) or userspace notifications.
 579
 580           If unsure, say Y.
 581
 582 config SHMEM
 583         bool "Use full shmem filesystem" if EMBEDDED
 584         default y
 585         depends on MMU
 586         help
 587           The shmem is an internal filesystem used to manage shared memory.
 588           It is backed by swap and manages resource limits. It is also exported
 589           to userspace as tmpfs if TMPFS is enabled. Disabling this
 590           option replaces shmem and tmpfs with the much simpler ramfs code,
 591           which may be appropriate on small systems without swap.
 592
 593 config VM_EVENT_COUNTERS
 594         default y
 595         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
 596         help
 597           VM event counters are needed for event counts to be shown.
 598           This option allows the disabling of the VM event counters
 599           on EMBEDDED systems.  /proc/vmstat will only show page counts
 600           if VM event counters are disabled.
 601
 602 config SLUB_DEBUG
 603         default y
 604         bool "Enable SLUB debugging support" if EMBEDDED
 605         depends on SLUB
 606         help
 607           SLUB has extensive debug support features. Disabling these can
 608           result in significant savings in code size. This also disables
 609           SLUB sysfs support. /sys/slab will not exist and there will be
 610           no support for cache validation etc.
 611
 612 choice
 613         prompt "Choose SLAB allocator"
 614         default SLUB
 615         help
 616            This option allows to select a slab allocator.
 617
 618 config SLAB
 619         bool "SLAB"
 620         help
 621           The regular slab allocator that is established and known to work
 622           well in all environments. It organizes cache hot objects in
 623           per cpu and per node queues. SLAB is the default choice for
 624           a slab allocator.
 625
 626 config SLUB
 627         bool "SLUB (Unqueued Allocator)"
 628         help
 629            SLUB is a slab allocator that minimizes cache line usage
 630            instead of managing queues of cached objects (SLAB approach).
 631            Per cpu caching is realized using slabs of objects instead
 632            of queues of objects. SLUB can use memory efficiently
 633            and has enhanced diagnostics.
 634
 635 config SLOB
 636         depends on EMBEDDED
 637         bool "SLOB (Simple Allocator)"
 638         help
 639            SLOB replaces the SLAB allocator with a drastically simpler
 640            allocator.  SLOB is more space efficient than SLAB but does not
 641            scale well (single lock for all operations) and is also highly
 642            susceptible to fragmentation. SLUB can accomplish a higher object
 643            density. It is usually better to use SLUB instead of SLOB.
 644
 645 endchoice
 646
 647 endmenu         # General setup
 648
 649 config RT_MUTEXES
 650         boolean
 651         select PLIST
 652
 653 config TINY_SHMEM
 654         default !SHMEM
 655         bool
 656
 657 config BASE_SMALL
 658         int
 659         default 0 if BASE_FULL
 660         default 1 if !BASE_FULL
 661
 662 menuconfig MODULES
 663         bool "Enable loadable module support"
 664         help
 665           Kernel modules are small pieces of compiled code which can
 666           be inserted in the running kernel, rather than being
 667           permanently built into the kernel.  You use the "modprobe"
 668           tool to add (and sometimes remove) them.  If you say Y here,
 669           many parts of the kernel can be built as modules (by
 670           answering M instead of Y where indicated): this is most
 671           useful for infrequently used options which are not required
 672           for booting.  For more information, see the man pages for
 673           modprobe, lsmod, modinfo, insmod and rmmod.
 674
 675           If you say Y here, you will need to run "make
 676           modules_install" to put the modules under /lib/modules/
 677           where modprobe can find them (you may need to be root to do
 678           this).
 679
 680           If unsure, say Y.
 681
 682 config MODULE_UNLOAD
 683         bool "Module unloading"
 684         depends on MODULES
 685         help
 686           Without this option you will not be able to unload any
 687           modules (note that some modules may not be unloadable
 688           anyway), which makes your kernel slightly smaller and
 689           simpler.  If unsure, say Y.
 690
 691 config MODULE_FORCE_UNLOAD
 692         bool "Forced module unloading"
 693         depends on MODULE_UNLOAD && EXPERIMENTAL
 694         help
 695           This option allows you to force a module to unload, even if the
 696           kernel believes it is unsafe: the kernel will remove the module
 697           without waiting for anyone to stop using it (using the -f option to
 698           rmmod).  This is mainly for kernel developers and desperate users.
 699           If unsure, say N.
 700
 701 config MODVERSIONS
 702         bool "Module versioning support"
 703         depends on MODULES
 704         help
 705           Usually, you have to use modules compiled with your kernel.
 706           Saying Y here makes it sometimes possible to use modules
 707           compiled for different kernels, by adding enough information
 708           to the modules to (hopefully) spot any changes which would
 709           make them incompatible with the kernel you are running.  If
 710           unsure, say N.
 711
 712 config MODULE_SRCVERSION_ALL
 713         bool "Source checksum for all modules"
 714         depends on MODULES
 715         help
 716           Modules which contain a MODULE_VERSION get an extra "srcversion"
 717           field inserted into their modinfo section, which contains a
 718           sum of the source files which made it.  This helps maintainers
 719           see exactly which source was used to build a module (since
 720           others sometimes change the module source without updating
 721           the version).  With this option, such a "srcversion" field
 722           will be created for all modules.  If unsure, say N.
 723
 724 config KMOD
 725         bool "Automatic kernel module loading"
 726         depends on MODULES
 727         help
 728           Normally when you have selected some parts of the kernel to
 729           be created as kernel modules, you must load them (using the
 730           "modprobe" command) before you can use them. If you say Y
 731           here, some parts of the kernel will be able to load modules
 732           automatically: when a part of the kernel needs a module, it
 733           runs modprobe with the appropriate arguments, thereby
 734           loading the module if it is available.  If unsure, say Y.
 735
 736 config STOP_MACHINE
 737         bool
 738         default y
 739         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
 740         help
 741           Need stop_machine() primitive.
 742
 743 source "block/Kconfig"
 744
 745 config PREEMPT_NOTIFIERS
 746         bool