init/Kconfig

   1 config ARCH
   2         string
   3         option env="ARCH"
   4
   5 config KERNELVERSION
   6         string
   7         option env="KERNELVERSION"
   8
   9 config DEFCONFIG_LIST
  10         string
  11         depends on !UML
  12         option defconfig_list
  13         default "/lib/modules/$UNAME_RELEASE/.config"
  14         default "/etc/kernel-config"
  15         default "/boot/config-$UNAME_RELEASE"
  16         default "arch/$ARCH/defconfig"
  17
  18 menu "General setup"
  19
  20 config EXPERIMENTAL
  21         bool "Prompt for development and/or incomplete code/drivers"
  22         ---help---
  23           Some of the various things that Linux supports (such as network
  24           drivers, file systems, network protocols, etc.) can be in a state
  25           of development where the functionality, stability, or the level of
  26           testing is not yet high enough for general use. This is usually
  27           known as the "alpha-test" phase among developers. If a feature is
  28           currently in alpha-test, then the developers usually discourage
  29           uninformed widespread use of this feature by the general public to
  30           avoid "Why doesn't this work?" type mail messages. However, active
  31           testing and use of these systems is welcomed. Just be aware that it
  32           may not meet the normal level of reliability or it may fail to work
  33           in some special cases. Detailed bug reports from people familiar
  34           with the kernel internals are usually welcomed by the developers
  35           (before submitting bug reports, please read the documents
  36           <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  37           <file:Documentation/BUG-HUNTING>, and
  38           <file:Documentation/oops-tracing.txt> in the kernel source).
  39
  40           This option will also make obsoleted drivers available. These are
  41           drivers that have been replaced by something else, and/or are
  42           scheduled to be removed in a future kernel release.
  43
  44           Unless you intend to help test and develop a feature or driver that
  45           falls into this category, or you have a situation that requires
  46           using these features, you should probably say N here, which will
  47           cause the configurator to present you with fewer choices. If
  48           you say Y here, you will be offered the choice of using features or
  49           drivers that are currently considered to be in the alpha-test phase.
  50
  51 config BROKEN
  52         bool
  53
  54 config BROKEN_ON_SMP
  55         bool
  56         depends on BROKEN || !SMP
  57         default y
  58
  59 config LOCK_KERNEL
  60         bool
  61         depends on SMP || PREEMPT
  62         default y
  63
  64 config INIT_ENV_ARG_LIMIT
  65         int
  66         default 32 if !UML
  67         default 128 if UML
  68         help
  69           Maximum of each of the number of arguments and environment
  70           variables passed to init from the kernel command line.
  71
  72
  73 config LOCALVERSION
  74         string "Local version - append to kernel release"
  75         help
  76           Append an extra string to the end of your kernel version.
  77           This will show up when you type uname, for example.
  78           The string you set here will be appended after the contents of
  79           any files with a filename matching localversion* in your
  80           object and source tree, in that order.  Your total string can
  81           be a maximum of 64 characters.
  82
  83 config LOCALVERSION_AUTO
  84         bool "Automatically append version information to the version string"
  85         default y
  86         help
  87           This will try to automatically determine if the current tree is a
  88           release tree by looking for git tags that belong to the current
  89           top of tree revision.
  90
  91           A string of the format -gxxxxxxxx will be added to the localversion
  92           if a git-based tree is found.  The string generated by this will be
  93           appended after any matching localversion* files, and after the value
  94           set in CONFIG_LOCALVERSION.
  95
  96           (The actual string used here is the first eight characters produced
  97           by running the command:
  98
  99             $ git rev-parse --verify HEAD
 100
 101           which is done within the script "scripts/setlocalversion".)
 102
 103 config SWAP
 104         bool "Support for paging of anonymous memory (swap)"
 105         depends on MMU && BLOCK
 106         default y
 107         help
 108           This option allows you to choose whether you want to have support
 109           for so called swap devices or swap files in your kernel that are
 110           used to provide more virtual memory than the actual RAM present
 111           in your computer.  If unsure say Y.
 112
 113 config SYSVIPC
 114         bool "System V IPC"
 115         ---help---
 116           Inter Process Communication is a suite of library functions and
 117           system calls which let processes (running programs) synchronize and
 118           exchange information. It is generally considered to be a good thing,
 119           and some programs won't run unless you say Y here. In particular, if
 120           you want to run the DOS emulator dosemu under Linux (read the
 121           DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 122           you'll need to say Y here.
 123
 124           You can find documentation about IPC with "info ipc" and also in
 125           section 6.4 of the Linux Programmer's Guide, available from
 126           <http://www.tldp.org/guides.html>.
 127
 128 config SYSVIPC_SYSCTL
 129         bool
 130         depends on SYSVIPC
 131         depends on SYSCTL
 132         default y
 133
 134 config POSIX_MQUEUE
 135         bool "POSIX Message Queues"
 136         depends on NET && EXPERIMENTAL
 137         ---help---
 138           POSIX variant of message queues is a part of IPC. In POSIX message
 139           queues every message has a priority which decides about succession
 140           of receiving it by a process. If you want to compile and run
 141           programs written e.g. for Solaris with use of its POSIX message
 142           queues (functions mq_*) say Y here.
 143
 144           POSIX message queues are visible as a filesystem called 'mqueue'
 145           and can be mounted somewhere if you want to do filesystem
 146           operations on message queues.
 147
 148           If unsure, say Y.
 149
 150 config BSD_PROCESS_ACCT
 151         bool "BSD Process Accounting"
 152         help
 153           If you say Y here, a user level program will be able to instruct the
 154           kernel (via a special system call) to write process accounting
 155           information to a file: whenever a process exits, information about
 156           that process will be appended to the file by the kernel.  The
 157           information includes things such as creation time, owning user,
 158           command name, memory usage, controlling terminal etc. (the complete
 159           list is in the struct acct in <file:include/linux/acct.h>).  It is
 160           up to the user level program to do useful things with this
 161           information.  This is generally a good idea, so say Y.
 162
 163 config BSD_PROCESS_ACCT_V3
 164         bool "BSD Process Accounting version 3 file format"
 165         depends on BSD_PROCESS_ACCT
 166         default n
 167         help
 168           If you say Y here, the process accounting information is written
 169           in a new file format that also logs the process IDs of each
 170           process and it's parent. Note that this file format is incompatible
 171           with previous v0/v1/v2 file formats, so you will need updated tools
 172           for processing it. A preliminary version of these tools is available
 173           at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
 174
 175 config TASKSTATS
 176         bool "Export task/process statistics through netlink (EXPERIMENTAL)"
 177         depends on NET
 178         default n
 179         help
 180           Export selected statistics for tasks/processes through the
 181           generic netlink interface. Unlike BSD process accounting, the
 182           statistics are available during the lifetime of tasks/processes as
 183           responses to commands. Like BSD accounting, they are sent to user
 184           space on task exit.
 185
 186           Say N if unsure.
 187
 188 config TASK_DELAY_ACCT
 189         bool "Enable per-task delay accounting (EXPERIMENTAL)"
 190         depends on TASKSTATS
 191         help
 192           Collect information on time spent by a task waiting for system
 193           resources like cpu, synchronous block I/O completion and swapping
 194           in pages. Such statistics can help in setting a task's priorities
 195           relative to other tasks for cpu, io, rss limits etc.
 196
 197           Say N if unsure.
 198
 199 config TASK_XACCT
 200         bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
 201         depends on TASKSTATS
 202         help
 203           Collect extended task accounting data and send the data
 204           to userland for processing over the taskstats interface.
 205
 206           Say N if unsure.
 207
 208 config TASK_IO_ACCOUNTING
 209         bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
 210         depends on TASK_XACCT
 211         help
 212           Collect information on the number of bytes of storage I/O which this
 213           task has caused.
 214
 215           Say N if unsure.
 216
 217 config AUDIT
 218         bool "Auditing support"
 219         depends on NET
 220         help
 221           Enable auditing infrastructure that can be used with another
 222           kernel subsystem, such as SELinux (which requires this for
 223           logging of avc messages output).  Does not do system-call
 224           auditing without CONFIG_AUDITSYSCALL.
 225
 226 config AUDITSYSCALL
 227         bool "Enable system-call auditing support"
 228         depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
 229         default y if SECURITY_SELINUX
 230         help
 231           Enable low-overhead system-call auditing infrastructure that
 232           can be used independently or with another kernel subsystem,
 233           such as SELinux.  To use audit's filesystem watch feature, please
 234           ensure that INOTIFY is configured.
 235
 236 config AUDIT_TREE
 237         def_bool y
 238         depends on AUDITSYSCALL && INOTIFY
 239
 240 config IKCONFIG
 241         tristate "Kernel .config support"
 242         ---help---
 243           This option enables the complete Linux kernel ".config" file
 244           contents to be saved in the kernel. It provides documentation
 245           of which kernel options are used in a running kernel or in an
 246           on-disk kernel.  This information can be extracted from the kernel
 247           image file with the script scripts/extract-ikconfig and used as
 248           input to rebuild the current kernel or to build another kernel.
 249           It can also be extracted from a running kernel by reading
 250           /proc/config.gz if enabled (below).
 251
 252 config IKCONFIG_PROC
 253         bool "Enable access to .config through /proc/config.gz"
 254         depends on IKCONFIG && PROC_FS
 255         ---help---
 256           This option enables access to the kernel configuration file
 257           through /proc/config.gz.
 258
 259 config LOG_BUF_SHIFT
 260         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 261         range 12 21
 262         default 17 if S390 || LOCKDEP
 263         default 16 if X86_NUMAQ || IA64
 264         default 15 if SMP
 265         default 14
 266         help
 267           Select kernel log buffer size as a power of 2.
 268           Defaults and Examples:
 269                      17 => 128 KB for S/390
 270                      16 => 64 KB for x86 NUMAQ or IA-64
 271                      15 => 32 KB for SMP
 272                      14 => 16 KB for uniprocessor
 273                      13 =>  8 KB
 274                      12 =>  4 KB
 275
 276 config CGROUPS
 277         bool "Control Group support"
 278         help
 279           This option will let you use process cgroup subsystems
 280           such as Cpusets
 281
 282           Say N if unsure.
 283
 284 config CGROUP_DEBUG
 285         bool "Example debug cgroup subsystem"
 286         depends on CGROUPS
 287         help
 288           This option enables a simple cgroup subsystem that
 289           exports useful debugging information about the cgroups
 290           framework
 291
 292           Say N if unsure
 293
 294 config CGROUP_NS
 295         bool "Namespace cgroup subsystem"
 296         depends on CGROUPS
 297         help
 298           Provides a simple namespace cgroup subsystem to
 299           provide hierarchical naming of sets of namespaces,
 300           for instance virtual servers and checkpoint/restart
 301           jobs.
 302
 303 config CPUSETS
 304         bool "Cpuset support"
 305         depends on SMP && CGROUPS
 306         help
 307           This option will let you create and manage CPUSETs which
 308           allow dynamically partitioning a system into sets of CPUs and
 309           Memory Nodes and assigning tasks to run only within those sets.
 310           This is primarily useful on large SMP or NUMA systems.
 311
 312           Say N if unsure.
 313
 314 config GROUP_SCHED
 315         bool "Group CPU scheduler"
 316         default y
 317         help
 318           This feature lets CPU scheduler recognize task groups and control CPU
 319           bandwidth allocation to such task groups.
 320
 321 config FAIR_GROUP_SCHED
 322         bool "Group scheduling for SCHED_OTHER"
 323         depends on GROUP_SCHED
 324         default y
 325
 326 config RT_GROUP_SCHED
 327         bool "Group scheduling for SCHED_RR/FIFO"
 328         depends on EXPERIMENTAL
 329         depends on GROUP_SCHED
 330         default n
 331
 332 choice
 333         depends on GROUP_SCHED
 334         prompt "Basis for grouping tasks"
 335         default USER_SCHED
 336
 337 config USER_SCHED
 338         bool "user id"
 339         help
 340           This option will choose userid as the basis for grouping
 341           tasks, thus providing equal CPU bandwidth to each user.
 342
 343 config CGROUP_SCHED
 344         bool "Control groups"
 345         depends on CGROUPS
 346         help
 347           This option allows you to create arbitrary task groups
 348           using the "cgroup" pseudo filesystem and control
 349           the cpu bandwidth allocated to each such task group.
 350           Refer to Documentation/cgroups.txt for more information
 351           on "cgroup" pseudo filesystem.
 352
 353 endchoice
 354
 355 config CGROUP_CPUACCT
 356         bool "Simple CPU accounting cgroup subsystem"
 357         depends on CGROUPS
 358         help
 359           Provides a simple Resource Controller for monitoring the
 360           total CPU consumed by the tasks in a cgroup
 361
 362 config RESOURCE_COUNTERS
 363         bool "Resource counters"
 364         help
 365           This option enables controller independent resource accounting
 366           infrastructure that works with cgroups
 367         depends on CGROUPS
 368
 369 config SYSFS_DEPRECATED
 370         bool "Create deprecated sysfs files"
 371         depends on SYSFS
 372         default y
 373         help
 374           This option creates deprecated symlinks such as the
 375           "device"-link, the <subsystem>:<name>-link, and the
 376           "bus"-link. It may also add deprecated key in the
 377           uevent environment.
 378           None of these features or values should be used today, as
 379           they export driver core implementation details to userspace
 380           or export properties which can't be kept stable across kernel
 381           releases.
 382
 383           If enabled, this option will also move any device structures
 384           that belong to a class, back into the /sys/class hierarchy, in
 385           order to support older versions of udev.
 386
 387           If you are using a distro that was released in 2006 or later,
 388           it should be safe to say N here.
 389
 390 config CGROUP_MEM_CONT
 391         bool "Memory controller for cgroups"
 392         depends on CGROUPS && RESOURCE_COUNTERS
 393         help
 394           Provides a memory controller that manages both page cache and
 395           RSS memory.
 396
 397 config PROC_PID_CPUSET
 398         bool "Include legacy /proc/<pid>/cpuset file"
 399         depends on CPUSETS
 400         default y
 401
 402 config RELAY
 403         bool "Kernel->user space relay support (formerly relayfs)"
 404         help
 405           This option enables support for relay interface support in
 406           certain file systems (such as debugfs).
 407           It is designed to provide an efficient mechanism for tools and
 408           facilities to relay large amounts of data from kernel space to
 409           user space.
 410
 411           If unsure, say N.
 412
 413 config NAMESPACES
 414         bool "Namespaces support" if EMBEDDED
 415         default !EMBEDDED
 416         help
 417           Provides the way to make tasks work with different objects using
 418           the same id. For example same IPC id may refer to different objects
 419           or same user id or pid may refer to different tasks when used in
 420           different namespaces.
 421
 422 config UTS_NS
 423         bool "UTS namespace"
 424         depends on NAMESPACES
 425         help
 426           In this namespace tasks see different info provided with the
 427           uname() system call
 428
 429 config IPC_NS
 430         bool "IPC namespace"
 431         depends on NAMESPACES && SYSVIPC
 432         help
 433           In this namespace tasks work with IPC ids which correspond to
 434           different IPC objects in different namespaces
 435
 436 config USER_NS
 437         bool "User namespace (EXPERIMENTAL)"
 438         depends on NAMESPACES && EXPERIMENTAL
 439         help
 440           This allows containers, i.e. vservers, to use user namespaces
 441           to provide different user info for different servers.
 442           If unsure, say N.
 443
 444 config PID_NS
 445         bool "PID Namespaces (EXPERIMENTAL)"
 446         default n
 447         depends on NAMESPACES && EXPERIMENTAL
 448         help
 449           Suport process id namespaces.  This allows having multiple
 450           process with the same pid as long as they are in different
 451           pid namespaces.  This is a building block of containers.
 452
 453           Unless you want to work with an experimental feature
 454           say N here.
 455
 456 config BLK_DEV_INITRD
 457         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 458         depends on BROKEN || !FRV
 459         help
 460           The initial RAM filesystem is a ramfs which is loaded by the
 461           boot loader (loadlin or lilo) and that is mounted as root
 462           before the normal boot procedure. It is typically used to
 463           load modules needed to mount the "real" root file system,
 464           etc. See <file:Documentation/initrd.txt> for details.
 465
 466           If RAM disk support (BLK_DEV_RAM) is also included, this
 467           also enables initial RAM disk (initrd) support and adds
 468           15 Kbytes (more on some other architectures) to the kernel size.
 469
 470           If unsure say Y.
 471
 472 if BLK_DEV_INITRD
 473
 474 source "usr/Kconfig"
 475
 476 endif
 477
 478 config CC_OPTIMIZE_FOR_SIZE
 479         bool "Optimize for size (Look out for broken compilers!)"
 480         default y
 481         depends on ARM || H8300 || SUPERH || EXPERIMENTAL
 482         help
 483           Enabling this option will pass "-Os" instead of "-O2" to gcc
 484           resulting in a smaller kernel.
 485
 486           WARNING: some versions of gcc may generate incorrect code with this
 487           option.  If problems are observed, a gcc upgrade may be needed.
 488
 489           If unsure, say N.
 490
 491 config SYSCTL
 492         bool
 493
 494 menuconfig EMBEDDED
 495         bool "Configure standard kernel features (for small systems)"
 496         help
 497           This option allows certain base kernel options and settings
 498           to be disabled or tweaked. This is for specialized
 499           environments which can tolerate a "non-standard" kernel.
 500           Only use this if you really know what you are doing.
 501
 502 config UID16
 503         bool "Enable 16-bit UID system calls" if EMBEDDED
 504         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
 505         default y
 506         help
 507           This enables the legacy 16-bit UID syscall wrappers.
 508
 509 config SYSCTL_SYSCALL
 510         bool "Sysctl syscall support" if EMBEDDED
 511         default y
 512         select SYSCTL
 513         ---help---
 514           sys_sysctl uses binary paths that have been found challenging
 515           to properly maintain and use.  The interface in /proc/sys
 516           using paths with ascii names is now the primary path to this
 517           information.
 518
 519           Almost nothing using the binary sysctl interface so if you are
 520           trying to save some space it is probably safe to disable this,
 521           making your kernel marginally smaller.
 522
 523           If unsure say Y here.
 524
 525 config KALLSYMS
 526          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 527          default y
 528          help
 529            Say Y here to let the kernel print out symbolic crash information and
 530            symbolic stack backtraces. This increases the size of the kernel
 531            somewhat, as all symbols have to be loaded into the kernel image.
 532
 533 config KALLSYMS_ALL
 534         bool "Include all symbols in kallsyms"
 535         depends on DEBUG_KERNEL && KALLSYMS
 536         help
 537            Normally kallsyms only contains the symbols of functions, for nicer
 538            OOPS messages.  Some debuggers can use kallsyms for other
 539            symbols too: say Y here to include all symbols, if you need them
 540            and you don't care about adding 300k to the size of your kernel.
 541
 542            Say N.
 543
 544 config KALLSYMS_EXTRA_PASS
 545         bool "Do an extra kallsyms pass"
 546         depends on KALLSYMS
 547         help
 548            If kallsyms is not working correctly, the build will fail with
 549            inconsistent kallsyms data.  If that occurs, log a bug report and
 550            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 551            Always say N here unless you find a bug in kallsyms, which must be
 552            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 553            you wait for kallsyms to be fixed.
 554
 555
 556 config HOTPLUG
 557         bool "Support for hot-pluggable devices" if EMBEDDED
 558         default y
 559         help
 560           This option is provided for the case where no hotplug or uevent
 561           capabilities is wanted by the kernel.  You should only consider
 562           disabling this option for embedded systems that do not use modules, a
 563           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 564
 565 config PRINTK
 566         default y
 567         bool "Enable support for printk" if EMBEDDED
 568         help
 569           This option enables normal printk support. Removing it
 570           eliminates most of the message strings from the kernel image
 571           and makes the kernel more or less silent. As this makes it
 572           very difficult to diagnose system problems, saying N here is
 573           strongly discouraged.
 574
 575 config BUG
 576         bool "BUG() support" if EMBEDDED
 577         default y
 578         help
 579           Disabling this option eliminates support for BUG and WARN, reducing
 580           the size of your kernel image and potentially quietly ignoring
 581           numerous fatal conditions. You should only consider disabling this
 582           option for embedded systems with no facilities for reporting errors.
 583           Just say Y.
 584
 585 config ELF_CORE
 586         default y
 587         bool "Enable ELF core dumps" if EMBEDDED
 588         help
 589           Enable support for generating core dumps. Disabling saves about 4k.
 590
 591 config COMPAT_BRK
 592         bool "Disable heap randomization"
 593         default y
 594         help
 595           Randomizing heap placement makes heap exploits harder, but it
 596           also breaks ancient binaries (including anything libc5 based).
 597           This option changes the bootup default to heap randomization
 598           disabled, and can be overriden runtime by setting
 599           /proc/sys/kernel/randomize_va_space to 2.
 600
 601           On non-ancient distros (post-2000 ones) N is usually a safe choice.
 602
 603 config BASE_FULL
 604         default y
 605         bool "Enable full-sized data structures for core" if EMBEDDED
 606         help
 607           Disabling this option reduces the size of miscellaneous core
 608           kernel data structures. This saves memory on small machines,
 609           but may reduce performance.
 610
 611 config FUTEX
 612         bool "Enable futex support" if EMBEDDED
 613         default y
 614         select RT_MUTEXES
 615         help
 616           Disabling this option will cause the kernel to be built without
 617           support for "fast userspace mutexes".  The resulting kernel may not
 618           run glibc-based applications correctly.
 619
 620 config ANON_INODES
 621         bool
 622
 623 config EPOLL
 624         bool "Enable eventpoll support" if EMBEDDED
 625         default y
 626         select ANON_INODES
 627         help
 628           Disabling this option will cause the kernel to be built without
 629           support for epoll family of system calls.
 630
 631 config SIGNALFD
 632         bool "Enable signalfd() system call" if EMBEDDED
 633         select ANON_INODES
 634         default y
 635         help
 636           Enable the signalfd() system call that allows to receive signals
 637           on a file descriptor.
 638
 639           If unsure, say Y.
 640
 641 config TIMERFD
 642         bool "Enable timerfd() system call" if EMBEDDED
 643         select ANON_INODES
 644         default y
 645         help
 646           Enable the timerfd() system call that allows to receive timer
 647           events on a file descriptor.
 648
 649           If unsure, say Y.
 650
 651 config EVENTFD
 652         bool "Enable eventfd() system call" if EMBEDDED
 653         select ANON_INODES
 654         default y
 655         help
 656           Enable the eventfd() system call that allows to receive both
 657           kernel notification (ie. KAIO) or userspace notifications.
 658
 659           If unsure, say Y.
 660
 661 config SHMEM
 662         bool "Use full shmem filesystem" if EMBEDDED
 663         default y
 664         depends on MMU
 665         help
 666           The shmem is an internal filesystem used to manage shared memory.
 667           It is backed by swap and manages resource limits. It is also exported
 668           to userspace as tmpfs if TMPFS is enabled. Disabling this
 669           option replaces shmem and tmpfs with the much simpler ramfs code,
 670           which may be appropriate on small systems without swap.
 671
 672 config VM_EVENT_COUNTERS
 673         default y
 674         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
 675         help
 676           VM event counters are needed for event counts to be shown.
 677           This option allows the disabling of the VM event counters
 678           on EMBEDDED systems.  /proc/vmstat will only show page counts
 679           if VM event counters are disabled.
 680
 681 config SLUB_DEBUG
 682         default y
 683         bool "Enable SLUB debugging support" if EMBEDDED
 684         depends on SLUB
 685         help
 686           SLUB has extensive debug support features. Disabling these can
 687           result in significant savings in code size. This also disables
 688           SLUB sysfs support. /sys/slab will not exist and there will be
 689           no support for cache validation etc.
 690
 691 choice
 692         prompt "Choose SLAB allocator"
 693         default SLUB
 694         help
 695            This option allows to select a slab allocator.
 696
 697 config SLAB
 698         bool "SLAB"
 699         help
 700           The regular slab allocator that is established and known to work
 701           well in all environments. It organizes cache hot objects in
 702           per cpu and per node queues. SLAB is the default choice for
 703           a slab allocator.
 704
 705 config SLUB
 706         bool "SLUB (Unqueued Allocator)"
 707         help
 708            SLUB is a slab allocator that minimizes cache line usage
 709            instead of managing queues of cached objects (SLAB approach).
 710            Per cpu caching is realized using slabs of objects instead
 711            of queues of objects. SLUB can use memory efficiently
 712            and has enhanced diagnostics.
 713
 714 config SLOB
 715         depends on EMBEDDED
 716         bool "SLOB (Simple Allocator)"
 717         help
 718            SLOB replaces the stock allocator with a drastically simpler
 719            allocator. SLOB is generally more space efficient but
 720            does not perform as well on large systems.
 721
 722 endchoice
 723
 724 config PROFILING
 725         bool "Profiling support (EXPERIMENTAL)"
 726         help
 727           Say Y here to enable the extended profiling support mechanisms used
 728           by profilers such as OProfile.
 729
 730 config MARKERS
 731         bool "Activate markers"
 732         help
 733           Place an empty function call at each marker site. Can be
 734           dynamically changed for a probe function.
 735
 736 source "arch/Kconfig"
 737
 738 config PROC_PAGE_MONITOR
 739         default y
 740         depends on PROC_FS && MMU
 741         bool "Enable /proc page monitoring" if EMBEDDED
 742         help
 743           Various /proc files exist to monitor process memory utilization:
 744           /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
 745           /proc/kpagecount, and /proc/kpageflags. Disabling these
 746           interfaces will reduce the size of the kernel by approximately 4kb.
 747
 748 endmenu         # General setup
 749
 750 config SLABINFO
 751         bool
 752         depends on PROC_FS
 753         depends on SLAB || SLUB
 754         default y
 755
 756 config RT_MUTEXES
 757         boolean
 758         select PLIST
 759
 760 config TINY_SHMEM
 761         default !SHMEM
 762         bool
 763
 764 config BASE_SMALL
 765         int
 766         default 0 if BASE_FULL
 767         default 1 if !BASE_FULL
 768
 769 menuconfig MODULES
 770         bool "Enable loadable module support"
 771         help
 772           Kernel modules are small pieces of compiled code which can
 773           be inserted in the running kernel, rather than being
 774           permanently built into the kernel.  You use the "modprobe"
 775           tool to add (and sometimes remove) them.  If you say Y here,
 776           many parts of the kernel can be built as modules (by
 777           answering M instead of Y where indicated): this is most
 778           useful for infrequently used options which are not required
 779           for booting.  For more information, see the man pages for
 780           modprobe, lsmod, modinfo, insmod and rmmod.
 781
 782           If you say Y here, you will need to run "make
 783           modules_install" to put the modules under /lib/modules/
 784           where modprobe can find them (you may need to be root to do
 785           this).
 786
 787           If unsure, say Y.
 788
 789 config MODULE_UNLOAD
 790         bool "Module unloading"
 791         depends on MODULES
 792         help
 793           Without this option you will not be able to unload any
 794           modules (note that some modules may not be unloadable
 795           anyway), which makes your kernel slightly smaller and
 796           simpler.  If unsure, say Y.
 797
 798 config MODULE_FORCE_UNLOAD
 799         bool "Forced module unloading"
 800         depends on MODULE_UNLOAD && EXPERIMENTAL
 801         help
 802           This option allows you to force a module to unload, even if the
 803           kernel believes it is unsafe: the kernel will remove the module
 804           without waiting for anyone to stop using it (using the -f option to
 805           rmmod).  This is mainly for kernel developers and desperate users.
 806           If unsure, say N.
 807
 808 config MODVERSIONS
 809         bool "Module versioning support"
 810         depends on MODULES
 811         help
 812           Usually, you have to use modules compiled with your kernel.
 813           Saying Y here makes it sometimes possible to use modules
 814           compiled for different kernels, by adding enough information
 815           to the modules to (hopefully) spot any changes which would
 816           make them incompatible with the kernel you are running.  If
 817           unsure, say N.
 818
 819 config MODULE_SRCVERSION_ALL
 820         bool "Source checksum for all modules"
 821         depends on MODULES
 822         help
 823           Modules which contain a MODULE_VERSION get an extra "srcversion"
 824           field inserted into their modinfo section, which contains a
 825           sum of the source files which made it.  This helps maintainers
 826           see exactly which source was used to build a module (since
 827           others sometimes change the module source without updating
 828           the version).  With this option, such a "srcversion" field
 829           will be created for all modules.  If unsure, say N.
 830
 831 config KMOD
 832         bool "Automatic kernel module loading"
 833         depends on MODULES
 834         help
 835           Normally when you have selected some parts of the kernel to
 836           be created as kernel modules, you must load them (using the
 837           "modprobe" command) before you can use them. If you say Y
 838           here, some parts of the kernel will be able to load modules
 839           automatically: when a part of the kernel needs a module, it
 840           runs modprobe with the appropriate arguments, thereby
 841           loading the module if it is available.  If unsure, say Y.
 842
 843 config STOP_MACHINE
 844         bool
 845         default y
 846         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
 847         help
 848           Need stop_machine() primitive.
 849
 850 source "block/Kconfig"
 851
 852 config PREEMPT_NOTIFIERS
 853         bool
 854
 855 choice
 856         prompt "RCU implementation type:"
 857         default CLASSIC_RCU
 858         help
 859           This allows you to choose either the classic RCU implementation
 860           that is designed for best read-side performance on non-realtime
 861           systems, or the preemptible RCU implementation for best latency
 862           on realtime systems.  Note that some kernel preemption modes
 863           will restrict your choice.
 864
 865           Select the default if you are unsure.
 866
 867 config CLASSIC_RCU
 868         bool "Classic RCU"
 869         help
 870           This option selects the classic RCU implementation that is
 871           designed for best read-side performance on non-realtime
 872           systems.
 873
 874           Say Y if you are unsure.
 875
 876 config PREEMPT_RCU
 877         bool "Preemptible RCU"
 878         depends on PREEMPT
 879         help
 880           This option reduces the latency of the kernel by making certain
 881           RCU sections preemptible. Normally RCU code is non-preemptible, if
 882           this option is selected then read-only RCU sections become
 883           preemptible. This helps latency, but may expose bugs due to
 884           now-naive assumptions about each RCU read-side critical section
 885           remaining on a given CPU through its execution.
 886
 887           Say N if you are unsure.
 888
 889 endchoice