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  41           drivers that have been replaced by something else, and/or are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