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  41           drivers that have been replaced by something else, and/or are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
 263         help
 264           Select kernel log buffer size as a power of 2.
 265           Examples:
 266                      17 => 128 KB
 267                      16 => 64 KB
 268                      15 => 32 KB
 269                      14 => 16 KB
 270                      13 =>  8 KB
 271                      12 =>  4 KB
 272
 273 config CGROUPS
 274         bool "Control Group support"
 275         help
 276           This option will let you use process cgroup subsystems
 277           such as Cpusets
 278
 279           Say N if unsure.
 280
 281 config CGROUP_DEBUG
 282         bool "Example debug cgroup subsystem"
 283         depends on CGROUPS
 284         default n
 285         help
 286           This option enables a simple cgroup subsystem that
 287           exports useful debugging information about the cgroups
 288           framework
 289
 290           Say N if unsure
 291
 292 config CGROUP_NS
 293         bool "Namespace cgroup subsystem"
 294         depends on CGROUPS
 295         help
 296           Provides a simple namespace cgroup subsystem to
 297           provide hierarchical naming of sets of namespaces,
 298           for instance virtual servers and checkpoint/restart
 299           jobs.
 300
 301 config CGROUP_DEVICE
 302         bool "Device controller for cgroups"
 303         depends on CGROUPS && EXPERIMENTAL
 304         help
 305           Provides a cgroup implementing whitelists for devices which
 306           a process in the cgroup can mknod or open.
 307
 308 config CPUSETS
 309         bool "Cpuset support"
 310         depends on SMP && CGROUPS
 311         help
 312           This option will let you create and manage CPUSETs which
 313           allow dynamically partitioning a system into sets of CPUs and
 314           Memory Nodes and assigning tasks to run only within those sets.
 315           This is primarily useful on large SMP or NUMA systems.
 316
 317           Say N if unsure.
 318
 319 config GROUP_SCHED
 320         bool "Group CPU scheduler"
 321         default y
 322         help
 323           This feature lets CPU scheduler recognize task groups and control CPU
 324           bandwidth allocation to such task groups.
 325
 326 config FAIR_GROUP_SCHED
 327         bool "Group scheduling for SCHED_OTHER"
 328         depends on GROUP_SCHED
 329         default y
 330
 331 config RT_GROUP_SCHED
 332         bool "Group scheduling for SCHED_RR/FIFO"
 333         depends on EXPERIMENTAL
 334         depends on GROUP_SCHED
 335         default n
 336         help
 337           This feature lets you explicitly allocate real CPU bandwidth
 338           to users or control groups (depending on the "Basis for grouping tasks"
 339           setting below. If enabled, it will also make it impossible to
 340           schedule realtime tasks for non-root users until you allocate
 341           realtime bandwidth for them.
 342           See Documentation/sched-rt-group.txt for more information.
 343
 344 choice
 345         depends on GROUP_SCHED
 346         prompt "Basis for grouping tasks"
 347         default USER_SCHED
 348
 349 config USER_SCHED
 350         bool "user id"
 351         help
 352           This option will choose userid as the basis for grouping
 353           tasks, thus providing equal CPU bandwidth to each user.
 354
 355 config CGROUP_SCHED
 356         bool "Control groups"
 357         depends on CGROUPS
 358         help
 359           This option allows you to create arbitrary task groups
 360           using the "cgroup" pseudo filesystem and control
 361           the cpu bandwidth allocated to each such task group.
 362           Refer to Documentation/cgroups.txt for more information
 363           on "cgroup" pseudo filesystem.
 364
 365 endchoice
 366
 367 config CGROUP_CPUACCT
 368         bool "Simple CPU accounting cgroup subsystem"
 369         depends on CGROUPS
 370         help
 371           Provides a simple Resource Controller for monitoring the
 372           total CPU consumed by the tasks in a cgroup
 373
 374 config RESOURCE_COUNTERS
 375         bool "Resource counters"
 376         help
 377           This option enables controller independent resource accounting
 378           infrastructure that works with cgroups
 379         depends on CGROUPS
 380
 381 config CGROUP_MEM_RES_CTLR
 382         bool "Memory Resource Controller for Control Groups"
 383         depends on CGROUPS && RESOURCE_COUNTERS
 384         help
 385           Provides a memory resource controller that manages both page cache and
 386           RSS memory.
 387
 388           Note that setting this option increases fixed memory overhead
 389           associated with each page of memory in the system by 4/8 bytes
 390           and also increases cache misses because struct page on many 64bit
 391           systems will not fit into a single cache line anymore.
 392
 393           Only enable when you're ok with these trade offs and really
 394           sure you need the memory resource controller.
 395
 396 config SYSFS_DEPRECATED
 397         bool
 398
 399 config SYSFS_DEPRECATED_V2
 400         bool "Create deprecated sysfs files"
 401         depends on SYSFS
 402         default y
 403         select SYSFS_DEPRECATED
 404         help
 405           This option creates deprecated symlinks such as the
 406           "device"-link, the <subsystem>:<name>-link, and the
 407           "bus"-link. It may also add deprecated key in the
 408           uevent environment.
 409           None of these features or values should be used today, as
 410           they export driver core implementation details to userspace
 411           or export properties which can't be kept stable across kernel
 412           releases.
 413
 414           If enabled, this option will also move any device structures
 415           that belong to a class, back into the /sys/class hierarchy, in
 416           order to support older versions of udev and some userspace
 417           programs.
 418
 419           If you are using a distro with the most recent userspace
 420           packages, it should be safe to say N here.
 421
 422 config PROC_PID_CPUSET
 423         bool "Include legacy /proc/<pid>/cpuset file"
 424         depends on CPUSETS
 425         default y
 426
 427 config RELAY
 428         bool "Kernel->user space relay support (formerly relayfs)"
 429         help
 430           This option enables support for relay interface support in
 431           certain file systems (such as debugfs).
 432           It is designed to provide an efficient mechanism for tools and
 433           facilities to relay large amounts of data from kernel space to
 434           user space.
 435
 436           If unsure, say N.
 437
 438 config NAMESPACES
 439         bool "Namespaces support" if EMBEDDED
 440         default !EMBEDDED
 441         help
 442           Provides the way to make tasks work with different objects using
 443           the same id. For example same IPC id may refer to different objects
 444           or same user id or pid may refer to different tasks when used in
 445           different namespaces.
 446
 447 config UTS_NS
 448         bool "UTS namespace"
 449         depends on NAMESPACES
 450         help
 451           In this namespace tasks see different info provided with the
 452           uname() system call
 453
 454 config IPC_NS
 455         bool "IPC namespace"
 456         depends on NAMESPACES && SYSVIPC
 457         help
 458           In this namespace tasks work with IPC ids which correspond to
 459           different IPC objects in different namespaces
 460
 461 config USER_NS
 462         bool "User namespace (EXPERIMENTAL)"
 463         depends on NAMESPACES && EXPERIMENTAL
 464         help
 465           This allows containers, i.e. vservers, to use user namespaces
 466           to provide different user info for different servers.
 467           If unsure, say N.
 468
 469 config PID_NS
 470         bool "PID Namespaces (EXPERIMENTAL)"
 471         default n
 472         depends on NAMESPACES && EXPERIMENTAL
 473         help
 474           Suport process id namespaces.  This allows having multiple
 475           process with the same pid as long as they are in different
 476           pid namespaces.  This is a building block of containers.
 477
 478           Unless you want to work with an experimental feature
 479           say N here.
 480
 481 config BLK_DEV_INITRD
 482         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 483         depends on BROKEN || !FRV
 484         help
 485           The initial RAM filesystem is a ramfs which is loaded by the
 486           boot loader (loadlin or lilo) and that is mounted as root
 487           before the normal boot procedure. It is typically used to
 488           load modules needed to mount the "real" root file system,
 489           etc. See <file:Documentation/initrd.txt> for details.
 490
 491           If RAM disk support (BLK_DEV_RAM) is also included, this
 492           also enables initial RAM disk (initrd) support and adds
 493           15 Kbytes (more on some other architectures) to the kernel size.
 494
 495           If unsure say Y.
 496
 497 if BLK_DEV_INITRD
 498
 499 source "usr/Kconfig"
 500
 501 endif
 502
 503 config CC_OPTIMIZE_FOR_SIZE
 504         bool "Optimize for size"
 505         default y
 506         help
 507           Enabling this option will pass "-Os" instead of "-O2" to gcc
 508           resulting in a smaller kernel.
 509
 510           If unsure, say N.
 511
 512 config SYSCTL
 513         bool
 514
 515 menuconfig EMBEDDED
 516         bool "Configure standard kernel features (for small systems)"
 517         help
 518           This option allows certain base kernel options and settings
 519           to be disabled or tweaked. This is for specialized
 520           environments which can tolerate a "non-standard" kernel.
 521           Only use this if you really know what you are doing.
 522
 523 config UID16
 524         bool "Enable 16-bit UID system calls" if EMBEDDED
 525         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 526         default y
 527         help
 528           This enables the legacy 16-bit UID syscall wrappers.
 529
 530 config SYSCTL_SYSCALL
 531         bool "Sysctl syscall support" if EMBEDDED
 532         default y
 533         select SYSCTL
 534         ---help---
 535           sys_sysctl uses binary paths that have been found challenging
 536           to properly maintain and use.  The interface in /proc/sys
 537           using paths with ascii names is now the primary path to this
 538           information.
 539
 540           Almost nothing using the binary sysctl interface so if you are
 541           trying to save some space it is probably safe to disable this,
 542           making your kernel marginally smaller.
 543
 544           If unsure say Y here.
 545
 546 config KALLSYMS
 547          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 548          default y
 549          help
 550            Say Y here to let the kernel print out symbolic crash information and
 551            symbolic stack backtraces. This increases the size of the kernel
 552            somewhat, as all symbols have to be loaded into the kernel image.
 553
 554 config KALLSYMS_ALL
 555         bool "Include all symbols in kallsyms"
 556         depends on DEBUG_KERNEL && KALLSYMS
 557         help
 558            Normally kallsyms only contains the symbols of functions, for nicer
 559            OOPS messages.  Some debuggers can use kallsyms for other
 560            symbols too: say Y here to include all symbols, if you need them
 561            and you don't care about adding 300k to the size of your kernel.
 562
 563            Say N.
 564
 565 config KALLSYMS_EXTRA_PASS
 566         bool "Do an extra kallsyms pass"
 567         depends on KALLSYMS
 568         help
 569            If kallsyms is not working correctly, the build will fail with
 570            inconsistent kallsyms data.  If that occurs, log a bug report and
 571            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 572            Always say N here unless you find a bug in kallsyms, which must be
 573            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 574            you wait for kallsyms to be fixed.
 575
 576
 577 config HOTPLUG
 578         bool "Support for hot-pluggable devices" if EMBEDDED
 579         default y
 580         help
 581           This option is provided for the case where no hotplug or uevent
 582           capabilities is wanted by the kernel.  You should only consider
 583           disabling this option for embedded systems that do not use modules, a
 584           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 585
 586 config PRINTK
 587         default y
 588         bool "Enable support for printk" if EMBEDDED
 589         help
 590           This option enables normal printk support. Removing it
 591           eliminates most of the message strings from the kernel image
 592           and makes the kernel more or less silent. As this makes it
 593           very difficult to diagnose system problems, saying N here is
 594           strongly discouraged.
 595
 596 config BUG
 597         bool "BUG() support" if EMBEDDED
 598         default y
 599         help
 600           Disabling this option eliminates support for BUG and WARN, reducing
 601           the size of your kernel image and potentially quietly ignoring
 602           numerous fatal conditions. You should only consider disabling this
 603           option for embedded systems with no facilities for reporting errors.
 604           Just say Y.
 605
 606 config ELF_CORE
 607         default y
 608         bool "Enable ELF core dumps" if EMBEDDED
 609         help
 610           Enable support for generating core dumps. Disabling saves about 4k.
 611
 612 config COMPAT_BRK
 613         bool "Disable heap randomization"
 614         default y
 615         help
 616           Randomizing heap placement makes heap exploits harder, but it
 617           also breaks ancient binaries (including anything libc5 based).
 618           This option changes the bootup default to heap randomization
 619           disabled, and can be overriden runtime by setting
 620           /proc/sys/kernel/randomize_va_space to 2.
 621
 622           On non-ancient distros (post-2000 ones) N is usually a safe choice.
 623
 624 config BASE_FULL
 625         default y
 626         bool "Enable full-sized data structures for core" if EMBEDDED
 627         help
 628           Disabling this option reduces the size of miscellaneous core
 629           kernel data structures. This saves memory on small machines,
 630           but may reduce performance.
 631
 632 config FUTEX
 633         bool "Enable futex support" if EMBEDDED
 634         default y
 635         select RT_MUTEXES
 636         help
 637           Disabling this option will cause the kernel to be built without
 638           support for "fast userspace mutexes".  The resulting kernel may not
 639           run glibc-based applications correctly.
 640
 641 config ANON_INODES
 642         bool
 643
 644 config EPOLL
 645         bool "Enable eventpoll support" if EMBEDDED
 646         default y
 647         select ANON_INODES
 648         help
 649           Disabling this option will cause the kernel to be built without
 650           support for epoll family of system calls.
 651
 652 config SIGNALFD
 653         bool "Enable signalfd() system call" if EMBEDDED
 654         select ANON_INODES
 655         default y
 656         help
 657           Enable the signalfd() system call that allows to receive signals
 658           on a file descriptor.
 659
 660           If unsure, say Y.
 661
 662 config TIMERFD
 663         bool "Enable timerfd() system call" if EMBEDDED
 664         select ANON_INODES
 665         default y
 666         help
 667           Enable the timerfd() system call that allows to receive timer
 668           events on a file descriptor.
 669
 670           If unsure, say Y.
 671
 672 config EVENTFD
 673         bool "Enable eventfd() system call" if EMBEDDED
 674         select ANON_INODES
 675         default y
 676         help
 677           Enable the eventfd() system call that allows to receive both
 678           kernel notification (ie. KAIO) or userspace notifications.
 679
 680           If unsure, say Y.
 681
 682 config SHMEM
 683         bool "Use full shmem filesystem" if EMBEDDED
 684         default y
 685         depends on MMU
 686         help
 687           The shmem is an internal filesystem used to manage shared memory.
 688           It is backed by swap and manages resource limits. It is also exported
 689           to userspace as tmpfs if TMPFS is enabled. Disabling this
 690           option replaces shmem and tmpfs with the much simpler ramfs code,
 691           which may be appropriate on small systems without swap.
 692
 693 config VM_EVENT_COUNTERS
 694         default y
 695         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
 696         help
 697           VM event counters are needed for event counts to be shown.
 698           This option allows the disabling of the VM event counters
 699           on EMBEDDED systems.  /proc/vmstat will only show page counts
 700           if VM event counters are disabled.
 701
 702 config SLUB_DEBUG
 703         default y
 704         bool "Enable SLUB debugging support" if EMBEDDED
 705         depends on SLUB
 706         help
 707           SLUB has extensive debug support features. Disabling these can
 708           result in significant savings in code size. This also disables
 709           SLUB sysfs support. /sys/slab will not exist and there will be
 710           no support for cache validation etc.
 711
 712 choice
 713         prompt "Choose SLAB allocator"
 714         default SLUB
 715         help
 716            This option allows to select a slab allocator.
 717
 718 config SLAB
 719         bool "SLAB"
 720         help
 721           The regular slab allocator that is established and known to work
 722           well in all environments. It organizes cache hot objects in
 723           per cpu and per node queues. SLAB is the default choice for
 724           a slab allocator.
 725
 726 config SLUB
 727         bool "SLUB (Unqueued Allocator)"
 728         help
 729            SLUB is a slab allocator that minimizes cache line usage
 730            instead of managing queues of cached objects (SLAB approach).
 731            Per cpu caching is realized using slabs of objects instead
 732            of queues of objects. SLUB can use memory efficiently
 733            and has enhanced diagnostics.
 734
 735 config SLOB
 736         depends on EMBEDDED
 737         bool "SLOB (Simple Allocator)"
 738         help
 739            SLOB replaces the stock allocator with a drastically simpler
 740            allocator. SLOB is generally more space efficient but
 741            does not perform as well on large systems.
 742
 743 endchoice
 744
 745 config PROFILING
 746         bool "Profiling support (EXPERIMENTAL)"
 747         help
 748           Say Y here to enable the extended profiling support mechanisms used
 749           by profilers such as OProfile.
 750
 751 config MARKERS
 752         bool "Activate markers"
 753         help
 754           Place an empty function call at each marker site. Can be
 755           dynamically changed for a probe function.
 756
 757 source "arch/Kconfig"
 758
 759 config PROC_PAGE_MONITOR
 760         default y
 761         depends on PROC_FS && MMU
 762         bool "Enable /proc page monitoring" if EMBEDDED
 763         help
 764           Various /proc files exist to monitor process memory utilization:
 765           /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
 766           /proc/kpagecount, and /proc/kpageflags. Disabling these
 767           interfaces will reduce the size of the kernel by approximately 4kb.
 768
 769 endmenu         # General setup
 770
 771 config SLABINFO
 772         bool
 773         depends on PROC_FS
 774         depends on SLAB || SLUB_DEBUG
 775         default y
 776
 777 config RT_MUTEXES
 778         boolean
 779         select PLIST
 780
 781 config TINY_SHMEM
 782         default !SHMEM
 783         bool
 784
 785 config BASE_SMALL
 786         int
 787         default 0 if BASE_FULL
 788         default 1 if !BASE_FULL
 789
 790 menuconfig MODULES
 791         bool "Enable loadable module support"
 792         help
 793           Kernel modules are small pieces of compiled code which can
 794           be inserted in the running kernel, rather than being
 795           permanently built into the kernel.  You use the "modprobe"
 796           tool to add (and sometimes remove) them.  If you say Y here,
 797           many parts of the kernel can be built as modules (by
 798           answering M instead of Y where indicated): this is most
 799           useful for infrequently used options which are not required
 800           for booting.  For more information, see the man pages for
 801           modprobe, lsmod, modinfo, insmod and rmmod.
 802
 803           If you say Y here, you will need to run "make
 804           modules_install" to put the modules under /lib/modules/
 805           where modprobe can find them (you may need to be root to do
 806           this).
 807
 808           If unsure, say Y.
 809
 810 config MODULE_UNLOAD
 811         bool "Module unloading"
 812         depends on MODULES
 813         help
 814           Without this option you will not be able to unload any
 815           modules (note that some modules may not be unloadable
 816           anyway), which makes your kernel slightly smaller and
 817           simpler.  If unsure, say Y.
 818
 819 config MODULE_FORCE_UNLOAD
 820         bool "Forced module unloading"
 821         depends on MODULE_UNLOAD && EXPERIMENTAL
 822         help
 823           This option allows you to force a module to unload, even if the
 824           kernel believes it is unsafe: the kernel will remove the module
 825           without waiting for anyone to stop using it (using the -f option to
 826           rmmod).  This is mainly for kernel developers and desperate users.
 827           If unsure, say N.
 828
 829 config MODVERSIONS
 830         bool "Module versioning support"
 831         depends on MODULES
 832         help
 833           Usually, you have to use modules compiled with your kernel.
 834           Saying Y here makes it sometimes possible to use modules
 835           compiled for different kernels, by adding enough information
 836           to the modules to (hopefully) spot any changes which would
 837           make them incompatible with the kernel you are running.  If
 838           unsure, say N.
 839
 840 config MODULE_SRCVERSION_ALL
 841         bool "Source checksum for all modules"
 842         depends on MODULES
 843         help
 844           Modules which contain a MODULE_VERSION get an extra "srcversion"
 845           field inserted into their modinfo section, which contains a
 846           sum of the source files which made it.  This helps maintainers
 847           see exactly which source was used to build a module (since
 848           others sometimes change the module source without updating
 849           the version).  With this option, such a "srcversion" field
 850           will be created for all modules.  If unsure, say N.
 851
 852 config KMOD
 853         bool "Automatic kernel module loading"
 854         depends on MODULES
 855         help
 856           Normally when you have selected some parts of the kernel to
 857           be created as kernel modules, you must load them (using the
 858           "modprobe" command) before you can use them. If you say Y
 859           here, some parts of the kernel will be able to load modules
 860           automatically: when a part of the kernel needs a module, it
 861           runs modprobe with the appropriate arguments, thereby
 862           loading the module if it is available.  If unsure, say Y.
 863
 864 config STOP_MACHINE
 865         bool
 866         default y
 867         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
 868         help
 869           Need stop_machine() primitive.
 870
 871 source "block/Kconfig"
 872
 873 config PREEMPT_NOTIFIERS
 874         bool
 875
 876 config CLASSIC_RCU
 877         def_bool !PREEMPT_RCU
 878         help
 879           This option selects the classic RCU implementation that is
 880           designed for best read-side performance on non-realtime
 881           systems.  Classic RCU is the default.  Note that the
 882           PREEMPT_RCU symbol is used to select/deselect this option.