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 "$ARCH_DEFCONFIG"
  17         default "arch/$ARCH/defconfig"
  18
  19 menu "General setup"
  20
  21 config EXPERIMENTAL
  22         bool "Prompt for development and/or incomplete code/drivers"
  23         ---help---
  24           Some of the various things that Linux supports (such as network
  25           drivers, file systems, network protocols, etc.) can be in a state
  26           of development where the functionality, stability, or the level of
  27           testing is not yet high enough for general use. This is usually
  28           known as the "alpha-test" phase among developers. If a feature is
  29           currently in alpha-test, then the developers usually discourage
  30           uninformed widespread use of this feature by the general public to
  31           avoid "Why doesn't this work?" type mail messages. However, active
  32           testing and use of these systems is welcomed. Just be aware that it
  33           may not meet the normal level of reliability or it may fail to work
  34           in some special cases. Detailed bug reports from people familiar
  35           with the kernel internals are usually welcomed by the developers
  36           (before submitting bug reports, please read the documents
  37           <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  38           <file:Documentation/BUG-HUNTING>, and
  39           <file:Documentation/oops-tracing.txt> in the kernel source).
  40
  41           This option will also make obsoleted drivers available. These are
  42           drivers that have been replaced by something else, and/or are
  43           scheduled to be removed in a future kernel release.
  44
  45           Unless you intend to help test and develop a feature or driver that
  46           falls into this category, or you have a situation that requires
  47           using these features, you should probably say N here, which will
  48           cause the configurator to present you with fewer choices. If
  49           you say Y here, you will be offered the choice of using features or
  50           drivers that are currently considered to be in the alpha-test phase.
  51
  52 config BROKEN
  53         bool
  54
  55 config BROKEN_ON_SMP
  56         bool
  57         depends on BROKEN || !SMP
  58         default y
  59
  60 config LOCK_KERNEL
  61         bool
  62         depends on SMP || PREEMPT
  63         default y
  64
  65 config INIT_ENV_ARG_LIMIT
  66         int
  67         default 32 if !UML
  68         default 128 if UML
  69         help
  70           Maximum of each of the number of arguments and environment
  71           variables passed to init from the kernel command line.
  72
  73
  74 config LOCALVERSION
  75         string "Local version - append to kernel release"
  76         help
  77           Append an extra string to the end of your kernel version.
  78           This will show up when you type uname, for example.
  79           The string you set here will be appended after the contents of
  80           any files with a filename matching localversion* in your
  81           object and source tree, in that order.  Your total string can
  82           be a maximum of 64 characters.
  83
  84 config LOCALVERSION_AUTO
  85         bool "Automatically append version information to the version string"
  86         default y
  87         help
  88           This will try to automatically determine if the current tree is a
  89           release tree by looking for git tags that belong to the current
  90           top of tree revision.
  91
  92           A string of the format -gxxxxxxxx will be added to the localversion
  93           if a git-based tree is found.  The string generated by this will be
  94           appended after any matching localversion* files, and after the value
  95           set in CONFIG_LOCALVERSION.
  96
  97           (The actual string used here is the first eight characters produced
  98           by running the command:
  99
 100             $ git rev-parse --verify HEAD
 101
 102           which is done within the script "scripts/setlocalversion".)
 103
 104 config SWAP
 105         bool "Support for paging of anonymous memory (swap)"
 106         depends on MMU && BLOCK
 107         default y
 108         help
 109           This option allows you to choose whether you want to have support
 110           for so called swap devices or swap files in your kernel that are
 111           used to provide more virtual memory than the actual RAM present
 112           in your computer.  If unsure say Y.
 113
 114 config SYSVIPC
 115         bool "System V IPC"
 116         ---help---
 117           Inter Process Communication is a suite of library functions and
 118           system calls which let processes (running programs) synchronize and
 119           exchange information. It is generally considered to be a good thing,
 120           and some programs won't run unless you say Y here. In particular, if
 121           you want to run the DOS emulator dosemu under Linux (read the
 122           DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 123           you'll need to say Y here.
 124
 125           You can find documentation about IPC with "info ipc" and also in
 126           section 6.4 of the Linux Programmer's Guide, available from
 127           <http://www.tldp.org/guides.html>.
 128
 129 config SYSVIPC_SYSCTL
 130         bool
 131         depends on SYSVIPC
 132         depends on SYSCTL
 133         default y
 134
 135 config POSIX_MQUEUE
 136         bool "POSIX Message Queues"
 137         depends on NET && EXPERIMENTAL
 138         ---help---
 139           POSIX variant of message queues is a part of IPC. In POSIX message
 140           queues every message has a priority which decides about succession
 141           of receiving it by a process. If you want to compile and run
 142           programs written e.g. for Solaris with use of its POSIX message
 143           queues (functions mq_*) say Y here.
 144
 145           POSIX message queues are visible as a filesystem called 'mqueue'
 146           and can be mounted somewhere if you want to do filesystem
 147           operations on message queues.
 148
 149           If unsure, say Y.
 150
 151 config BSD_PROCESS_ACCT
 152         bool "BSD Process Accounting"
 153         help
 154           If you say Y here, a user level program will be able to instruct the
 155           kernel (via a special system call) to write process accounting
 156           information to a file: whenever a process exits, information about
 157           that process will be appended to the file by the kernel.  The
 158           information includes things such as creation time, owning user,
 159           command name, memory usage, controlling terminal etc. (the complete
 160           list is in the struct acct in <file:include/linux/acct.h>).  It is
 161           up to the user level program to do useful things with this
 162           information.  This is generally a good idea, so say Y.
 163
 164 config BSD_PROCESS_ACCT_V3
 165         bool "BSD Process Accounting version 3 file format"
 166         depends on BSD_PROCESS_ACCT
 167         default n
 168         help
 169           If you say Y here, the process accounting information is written
 170           in a new file format that also logs the process IDs of each
 171           process and it's parent. Note that this file format is incompatible
 172           with previous v0/v1/v2 file formats, so you will need updated tools
 173           for processing it. A preliminary version of these tools is available
 174           at <http://www.gnu.org/software/acct/>.
 175
 176 config TASKSTATS
 177         bool "Export task/process statistics through netlink (EXPERIMENTAL)"
 178         depends on NET
 179         default n
 180         help
 181           Export selected statistics for tasks/processes through the
 182           generic netlink interface. Unlike BSD process accounting, the
 183           statistics are available during the lifetime of tasks/processes as
 184           responses to commands. Like BSD accounting, they are sent to user
 185           space on task exit.
 186
 187           Say N if unsure.
 188
 189 config TASK_DELAY_ACCT
 190         bool "Enable per-task delay accounting (EXPERIMENTAL)"
 191         depends on TASKSTATS
 192         help
 193           Collect information on time spent by a task waiting for system
 194           resources like cpu, synchronous block I/O completion and swapping
 195           in pages. Such statistics can help in setting a task's priorities
 196           relative to other tasks for cpu, io, rss limits etc.
 197
 198           Say N if unsure.
 199
 200 config TASK_XACCT
 201         bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
 202         depends on TASKSTATS
 203         help
 204           Collect extended task accounting data and send the data
 205           to userland for processing over the taskstats interface.
 206
 207           Say N if unsure.
 208
 209 config TASK_IO_ACCOUNTING
 210         bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
 211         depends on TASK_XACCT
 212         help
 213           Collect information on the number of bytes of storage I/O which this
 214           task has caused.
 215
 216           Say N if unsure.
 217
 218 config AUDIT
 219         bool "Auditing support"
 220         depends on NET
 221         help
 222           Enable auditing infrastructure that can be used with another
 223           kernel subsystem, such as SELinux (which requires this for
 224           logging of avc messages output).  Does not do system-call
 225           auditing without CONFIG_AUDITSYSCALL.
 226
 227 config AUDITSYSCALL
 228         bool "Enable system-call auditing support"
 229         depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
 230         default y if SECURITY_SELINUX
 231         help
 232           Enable low-overhead system-call auditing infrastructure that
 233           can be used independently or with another kernel subsystem,
 234           such as SELinux.  To use audit's filesystem watch feature, please
 235           ensure that INOTIFY is configured.
 236
 237 config AUDIT_TREE
 238         def_bool y
 239         depends on AUDITSYSCALL && INOTIFY
 240
 241 config IKCONFIG
 242         tristate "Kernel .config support"
 243         ---help---
 244           This option enables the complete Linux kernel ".config" file
 245           contents to be saved in the kernel. It provides documentation
 246           of which kernel options are used in a running kernel or in an
 247           on-disk kernel.  This information can be extracted from the kernel
 248           image file with the script scripts/extract-ikconfig and used as
 249           input to rebuild the current kernel or to build another kernel.
 250           It can also be extracted from a running kernel by reading
 251           /proc/config.gz if enabled (below).
 252
 253 config IKCONFIG_PROC
 254         bool "Enable access to .config through /proc/config.gz"
 255         depends on IKCONFIG && PROC_FS
 256         ---help---
 257           This option enables access to the kernel configuration file
 258           through /proc/config.gz.
 259
 260 config LOG_BUF_SHIFT
 261         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 262         range 12 21
 263         default 17
 264         help
 265           Select kernel log buffer size as a power of 2.
 266           Examples:
 267                      17 => 128 KB
 268                      16 => 64 KB
 269                      15 => 32 KB
 270                      14 => 16 KB
 271                      13 =>  8 KB
 272                      12 =>  4 KB
 273
 274 config CGROUPS
 275         bool "Control Group support"
 276         help
 277           This option will let you use process cgroup subsystems
 278           such as Cpusets
 279
 280           Say N if unsure.
 281
 282 config CGROUP_DEBUG
 283         bool "Example debug cgroup subsystem"
 284         depends on CGROUPS
 285         default n
 286         help
 287           This option enables a simple cgroup subsystem that
 288           exports useful debugging information about the cgroups
 289           framework
 290
 291           Say N if unsure
 292
 293 config CGROUP_NS
 294         bool "Namespace cgroup subsystem"
 295         depends on CGROUPS
 296         help
 297           Provides a simple namespace cgroup subsystem to
 298           provide hierarchical naming of sets of namespaces,
 299           for instance virtual servers and checkpoint/restart
 300           jobs.
 301
 302 config CGROUP_FREEZER
 303         bool "control group freezer subsystem"
 304         depends on CGROUPS
 305         help
 306           Provides a way to freeze and unfreeze all tasks in a
 307           cgroup.
 308
 309 config CGROUP_DEVICE
 310         bool "Device controller for cgroups"
 311         depends on CGROUPS && EXPERIMENTAL
 312         help
 313           Provides a cgroup implementing whitelists for devices which
 314           a process in the cgroup can mknod or open.
 315
 316 config CPUSETS
 317         bool "Cpuset support"
 318         depends on SMP && CGROUPS
 319         help
 320           This option will let you create and manage CPUSETs which
 321           allow dynamically partitioning a system into sets of CPUs and
 322           Memory Nodes and assigning tasks to run only within those sets.
 323           This is primarily useful on large SMP or NUMA systems.
 324
 325           Say N if unsure.
 326
 327 #
 328 # Architectures with an unreliable sched_clock() should select this:
 329 #
 330 config HAVE_UNSTABLE_SCHED_CLOCK
 331         bool
 332
 333 config GROUP_SCHED
 334         bool "Group CPU scheduler"
 335         depends on EXPERIMENTAL
 336         default n
 337         help
 338           This feature lets CPU scheduler recognize task groups and control CPU
 339           bandwidth allocation to such task groups.
 340
 341 config FAIR_GROUP_SCHED
 342         bool "Group scheduling for SCHED_OTHER"
 343         depends on GROUP_SCHED
 344         default GROUP_SCHED
 345
 346 config RT_GROUP_SCHED
 347         bool "Group scheduling for SCHED_RR/FIFO"
 348         depends on EXPERIMENTAL
 349         depends on GROUP_SCHED
 350         default n
 351         help
 352           This feature lets you explicitly allocate real CPU bandwidth
 353           to users or control groups (depending on the "Basis for grouping tasks"
 354           setting below. If enabled, it will also make it impossible to
 355           schedule realtime tasks for non-root users until you allocate
 356           realtime bandwidth for them.
 357           See Documentation/sched-rt-group.txt for more information.
 358
 359 choice
 360         depends on GROUP_SCHED
 361         prompt "Basis for grouping tasks"
 362         default USER_SCHED
 363
 364 config USER_SCHED
 365         bool "user id"
 366         help
 367           This option will choose userid as the basis for grouping
 368           tasks, thus providing equal CPU bandwidth to each user.
 369
 370 config CGROUP_SCHED
 371         bool "Control groups"
 372         depends on CGROUPS
 373         help
 374           This option allows you to create arbitrary task groups
 375           using the "cgroup" pseudo filesystem and control
 376           the cpu bandwidth allocated to each such task group.
 377           Refer to Documentation/cgroups.txt for more information
 378           on "cgroup" pseudo filesystem.
 379
 380 endchoice
 381
 382 config CGROUP_CPUACCT
 383         bool "Simple CPU accounting cgroup subsystem"
 384         depends on CGROUPS
 385         help
 386           Provides a simple Resource Controller for monitoring the
 387           total CPU consumed by the tasks in a cgroup
 388
 389 config RESOURCE_COUNTERS
 390         bool "Resource counters"
 391         help
 392           This option enables controller independent resource accounting
 393           infrastructure that works with cgroups
 394         depends on CGROUPS
 395
 396 config MM_OWNER
 397         bool
 398
 399 config CGROUP_MEM_RES_CTLR
 400         bool "Memory Resource Controller for Control Groups"
 401         depends on CGROUPS && RESOURCE_COUNTERS
 402         select MM_OWNER
 403         help
 404           Provides a memory resource controller that manages both page cache and
 405           RSS memory.
 406
 407           Note that setting this option increases fixed memory overhead
 408           associated with each page of memory in the system by 4/8 bytes
 409           and also increases cache misses because struct page on many 64bit
 410           systems will not fit into a single cache line anymore.
 411
 412           Only enable when you're ok with these trade offs and really
 413           sure you need the memory resource controller.
 414
 415           This config option also selects MM_OWNER config option, which
 416           could in turn add some fork/exit overhead.
 417
 418 config SYSFS_DEPRECATED
 419         bool
 420
 421 config SYSFS_DEPRECATED_V2
 422         bool "Create deprecated sysfs files"
 423         depends on SYSFS
 424         default y
 425         select SYSFS_DEPRECATED
 426         help
 427           This option creates deprecated symlinks such as the
 428           "device"-link, the <subsystem>:<name>-link, and the
 429           "bus"-link. It may also add deprecated key in the
 430           uevent environment.
 431           None of these features or values should be used today, as
 432           they export driver core implementation details to userspace
 433           or export properties which can't be kept stable across kernel
 434           releases.
 435
 436           If enabled, this option will also move any device structures
 437           that belong to a class, back into the /sys/class hierarchy, in
 438           order to support older versions of udev and some userspace
 439           programs.
 440
 441           If you are using a distro with the most recent userspace
 442           packages, it should be safe to say N here.
 443
 444 config PROC_PID_CPUSET
 445         bool "Include legacy /proc/<pid>/cpuset file"
 446         depends on CPUSETS
 447         default y
 448
 449 config RELAY
 450         bool "Kernel->user space relay support (formerly relayfs)"
 451         help
 452           This option enables support for relay interface support in
 453           certain file systems (such as debugfs).
 454           It is designed to provide an efficient mechanism for tools and
 455           facilities to relay large amounts of data from kernel space to
 456           user space.
 457
 458           If unsure, say N.
 459
 460 config NAMESPACES
 461         bool "Namespaces support" if EMBEDDED
 462         default !EMBEDDED
 463         help
 464           Provides the way to make tasks work with different objects using
 465           the same id. For example same IPC id may refer to different objects
 466           or same user id or pid may refer to different tasks when used in
 467           different namespaces.
 468
 469 config UTS_NS
 470         bool "UTS namespace"
 471         depends on NAMESPACES
 472         help
 473           In this namespace tasks see different info provided with the
 474           uname() system call
 475
 476 config IPC_NS
 477         bool "IPC namespace"
 478         depends on NAMESPACES && SYSVIPC
 479         help
 480           In this namespace tasks work with IPC ids which correspond to
 481           different IPC objects in different namespaces
 482
 483 config USER_NS
 484         bool "User namespace (EXPERIMENTAL)"
 485         depends on NAMESPACES && EXPERIMENTAL
 486         help
 487           This allows containers, i.e. vservers, to use user namespaces
 488           to provide different user info for different servers.
 489           If unsure, say N.
 490
 491 config PID_NS
 492         bool "PID Namespaces (EXPERIMENTAL)"
 493         default n
 494         depends on NAMESPACES && EXPERIMENTAL
 495         help
 496           Support process id namespaces.  This allows having multiple
 497           process with the same pid as long as they are in different
 498           pid namespaces.  This is a building block of containers.
 499
 500           Unless you want to work with an experimental feature
 501           say N here.
 502
 503 config BLK_DEV_INITRD
 504         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 505         depends on BROKEN || !FRV
 506         help
 507           The initial RAM filesystem is a ramfs which is loaded by the
 508           boot loader (loadlin or lilo) and that is mounted as root
 509           before the normal boot procedure. It is typically used to
 510           load modules needed to mount the "real" root file system,
 511           etc. See <file:Documentation/initrd.txt> for details.
 512
 513           If RAM disk support (BLK_DEV_RAM) is also included, this
 514           also enables initial RAM disk (initrd) support and adds
 515           15 Kbytes (more on some other architectures) to the kernel size.
 516
 517           If unsure say Y.
 518
 519 if BLK_DEV_INITRD
 520
 521 source "usr/Kconfig"
 522
 523 endif
 524
 525 config CC_OPTIMIZE_FOR_SIZE
 526         bool "Optimize for size"
 527         default y
 528         help
 529           Enabling this option will pass "-Os" instead of "-O2" to gcc
 530           resulting in a smaller kernel.
 531
 532           If unsure, say Y.
 533
 534 config SYSCTL
 535         bool
 536
 537 menuconfig EMBEDDED
 538         bool "Configure standard kernel features (for small systems)"
 539         help
 540           This option allows certain base kernel options and settings
 541           to be disabled or tweaked. This is for specialized
 542           environments which can tolerate a "non-standard" kernel.
 543           Only use this if you really know what you are doing.
 544
 545 config UID16
 546         bool "Enable 16-bit UID system calls" if EMBEDDED
 547         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 548         default y
 549         help
 550           This enables the legacy 16-bit UID syscall wrappers.
 551
 552 config SYSCTL_SYSCALL
 553         bool "Sysctl syscall support" if EMBEDDED
 554         default y
 555         select SYSCTL
 556         ---help---
 557           sys_sysctl uses binary paths that have been found challenging
 558           to properly maintain and use.  The interface in /proc/sys
 559           using paths with ascii names is now the primary path to this
 560           information.
 561
 562           Almost nothing using the binary sysctl interface so if you are
 563           trying to save some space it is probably safe to disable this,
 564           making your kernel marginally smaller.
 565
 566           If unsure say Y here.
 567
 568 config KALLSYMS
 569          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 570          default y
 571          help
 572            Say Y here to let the kernel print out symbolic crash information and
 573            symbolic stack backtraces. This increases the size of the kernel
 574            somewhat, as all symbols have to be loaded into the kernel image.
 575
 576 config KALLSYMS_ALL
 577         bool "Include all symbols in kallsyms"
 578         depends on DEBUG_KERNEL && KALLSYMS
 579         help
 580            Normally kallsyms only contains the symbols of functions, for nicer
 581            OOPS messages.  Some debuggers can use kallsyms for other
 582            symbols too: say Y here to include all symbols, if you need them
 583            and you don't care about adding 300k to the size of your kernel.
 584
 585            Say N.
 586
 587 config KALLSYMS_EXTRA_PASS
 588         bool "Do an extra kallsyms pass"
 589         depends on KALLSYMS
 590         help
 591            If kallsyms is not working correctly, the build will fail with
 592            inconsistent kallsyms data.  If that occurs, log a bug report and
 593            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 594            Always say N here unless you find a bug in kallsyms, which must be
 595            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 596            you wait for kallsyms to be fixed.
 597
 598
 599 config HOTPLUG
 600         bool "Support for hot-pluggable devices" if EMBEDDED
 601         default y
 602         help
 603           This option is provided for the case where no hotplug or uevent
 604           capabilities is wanted by the kernel.  You should only consider
 605           disabling this option for embedded systems that do not use modules, a
 606           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 607
 608 config PRINTK
 609         default y
 610         bool "Enable support for printk" if EMBEDDED
 611         help
 612           This option enables normal printk support. Removing it
 613           eliminates most of the message strings from the kernel image
 614           and makes the kernel more or less silent. As this makes it
 615           very difficult to diagnose system problems, saying N here is
 616           strongly discouraged.
 617
 618 config BUG
 619         bool "BUG() support" if EMBEDDED
 620         default y
 621         help
 622           Disabling this option eliminates support for BUG and WARN, reducing
 623           the size of your kernel image and potentially quietly ignoring
 624           numerous fatal conditions. You should only consider disabling this
 625           option for embedded systems with no facilities for reporting errors.
 626           Just say Y.
 627
 628 config ELF_CORE
 629         default y
 630         bool "Enable ELF core dumps" if EMBEDDED
 631         help
 632           Enable support for generating core dumps. Disabling saves about 4k.
 633
 634 config PCSPKR_PLATFORM
 635         bool "Enable PC-Speaker support" if EMBEDDED
 636         depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
 637         default y
 638         help
 639           This option allows to disable the internal PC-Speaker
 640           support, saving some memory.
 641
 642 config COMPAT_BRK
 643         bool "Disable heap randomization"
 644         default y
 645         help
 646           Randomizing heap placement makes heap exploits harder, but it
 647           also breaks ancient binaries (including anything libc5 based).
 648           This option changes the bootup default to heap randomization
 649           disabled, and can be overriden runtime by setting
 650           /proc/sys/kernel/randomize_va_space to 2.
 651
 652           On non-ancient distros (post-2000 ones) N is usually a safe choice.
 653
 654 config BASE_FULL
 655         default y
 656         bool "Enable full-sized data structures for core" if EMBEDDED
 657         help
 658           Disabling this option reduces the size of miscellaneous core
 659           kernel data structures. This saves memory on small machines,
 660           but may reduce performance.
 661
 662 config FUTEX
 663         bool "Enable futex support" if EMBEDDED
 664         default y
 665         select RT_MUTEXES
 666         help
 667           Disabling this option will cause the kernel to be built without
 668           support for "fast userspace mutexes".  The resulting kernel may not
 669           run glibc-based applications correctly.
 670
 671 config ANON_INODES
 672         bool
 673
 674 config EPOLL
 675         bool "Enable eventpoll support" if EMBEDDED
 676         default y
 677         select ANON_INODES
 678         help
 679           Disabling this option will cause the kernel to be built without
 680           support for epoll family of system calls.
 681
 682 config SIGNALFD
 683         bool "Enable signalfd() system call" if EMBEDDED
 684         select ANON_INODES
 685         default y
 686         help
 687           Enable the signalfd() system call that allows to receive signals
 688           on a file descriptor.
 689
 690           If unsure, say Y.
 691
 692 config TIMERFD
 693         bool "Enable timerfd() system call" if EMBEDDED
 694         select ANON_INODES
 695         default y
 696         help
 697           Enable the timerfd() system call that allows to receive timer
 698           events on a file descriptor.
 699
 700           If unsure, say Y.
 701
 702 config EVENTFD
 703         bool "Enable eventfd() system call" if EMBEDDED
 704         select ANON_INODES
 705         default y
 706         help
 707           Enable the eventfd() system call that allows to receive both
 708           kernel notification (ie. KAIO) or userspace notifications.
 709
 710           If unsure, say Y.
 711
 712 config SHMEM
 713         bool "Use full shmem filesystem" if EMBEDDED
 714         default y
 715         depends on MMU
 716         help
 717           The shmem is an internal filesystem used to manage shared memory.
 718           It is backed by swap and manages resource limits. It is also exported
 719           to userspace as tmpfs if TMPFS is enabled. Disabling this
 720           option replaces shmem and tmpfs with the much simpler ramfs code,
 721           which may be appropriate on small systems without swap.
 722
 723 config AIO
 724         bool "Enable AIO support" if EMBEDDED
 725         default y
 726         help
 727           This option enables POSIX asynchronous I/O which may by used
 728           by some high performance threaded applications. Disabling
 729           this option saves about 7k.
 730
 731 config VM_EVENT_COUNTERS
 732         default y
 733         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
 734         help
 735           VM event counters are needed for event counts to be shown.
 736           This option allows the disabling of the VM event counters
 737           on EMBEDDED systems.  /proc/vmstat will only show page counts
 738           if VM event counters are disabled.
 739
 740 config PCI_QUIRKS
 741         default y
 742         bool "Enable PCI quirk workarounds" if EMBEDDED
 743         depends on PCI
 744         help
 745           This enables workarounds for various PCI chipset
 746           bugs/quirks. Disable this only if your target machine is
 747           unaffected by PCI quirks.
 748
 749 config SLUB_DEBUG
 750         default y
 751         bool "Enable SLUB debugging support" if EMBEDDED
 752         depends on SLUB && SYSFS
 753         help
 754           SLUB has extensive debug support features. Disabling these can
 755           result in significant savings in code size. This also disables
 756           SLUB sysfs support. /sys/slab will not exist and there will be
 757           no support for cache validation etc.
 758
 759 choice
 760         prompt "Choose SLAB allocator"
 761         default SLUB
 762         help
 763            This option allows to select a slab allocator.
 764
 765 config SLAB
 766         bool "SLAB"
 767         help
 768           The regular slab allocator that is established and known to work
 769           well in all environments. It organizes cache hot objects in
 770           per cpu and per node queues. SLAB is the default choice for
 771           a slab allocator.
 772
 773 config SLUB
 774         bool "SLUB (Unqueued Allocator)"
 775         help
 776            SLUB is a slab allocator that minimizes cache line usage
 777            instead of managing queues of cached objects (SLAB approach).
 778            Per cpu caching is realized using slabs of objects instead
 779            of queues of objects. SLUB can use memory efficiently
 780            and has enhanced diagnostics.
 781
 782 config SLOB
 783         depends on EMBEDDED
 784         bool "SLOB (Simple Allocator)"
 785         help
 786            SLOB replaces the stock allocator with a drastically simpler
 787            allocator. SLOB is generally more space efficient but
 788            does not perform as well on large systems.
 789
 790 endchoice
 791
 792 config PROFILING
 793         bool "Profiling support (EXPERIMENTAL)"
 794         help
 795           Say Y here to enable the extended profiling support mechanisms used
 796           by profilers such as OProfile.
 797
 798 #
 799 # Place an empty function call at each tracepoint site. Can be
 800 # dynamically changed for a probe function.
 801 #
 802 config TRACEPOINTS
 803         bool
 804
 805 config MARKERS
 806         bool "Activate markers"
 807         help
 808           Place an empty function call at each marker site. Can be
 809           dynamically changed for a probe function.
 810
 811 source "arch/Kconfig"
 812
 813 endmenu         # General setup
 814
 815 config HAVE_GENERIC_DMA_COHERENT
 816         bool
 817         default n
 818
 819 config SLABINFO
 820         bool
 821         depends on PROC_FS
 822         depends on SLAB || SLUB_DEBUG
 823         default y
 824
 825 config RT_MUTEXES
 826         boolean
 827         select PLIST
 828
 829 config TINY_SHMEM
 830         default !SHMEM
 831         bool
 832
 833 config BASE_SMALL
 834         int
 835         default 0 if BASE_FULL
 836         default 1 if !BASE_FULL
 837
 838 menuconfig MODULES
 839         bool "Enable loadable module support"
 840         help
 841           Kernel modules are small pieces of compiled code which can
 842           be inserted in the running kernel, rather than being
 843           permanently built into the kernel.  You use the "modprobe"
 844           tool to add (and sometimes remove) them.  If you say Y here,
 845           many parts of the kernel can be built as modules (by
 846           answering M instead of Y where indicated): this is most
 847           useful for infrequently used options which are not required
 848           for booting.  For more information, see the man pages for
 849           modprobe, lsmod, modinfo, insmod and rmmod.
 850
 851           If you say Y here, you will need to run "make
 852           modules_install" to put the modules under /lib/modules/
 853           where modprobe can find them (you may need to be root to do
 854           this).
 855
 856           If unsure, say Y.
 857
 858 if MODULES
 859
 860 config MODULE_FORCE_LOAD
 861         bool "Forced module loading"
 862         default n
 863         help
 864           Allow loading of modules without version information (ie. modprobe
 865           --force).  Forced module loading sets the 'F' (forced) taint flag and
 866           is usually a really bad idea.
 867
 868 config MODULE_UNLOAD
 869         bool "Module unloading"
 870         help
 871           Without this option you will not be able to unload any
 872           modules (note that some modules may not be unloadable
 873           anyway), which makes your kernel smaller, faster
 874           and simpler.  If unsure, say Y.
 875
 876 config MODULE_FORCE_UNLOAD
 877         bool "Forced module unloading"
 878         depends on MODULE_UNLOAD && EXPERIMENTAL
 879         help
 880           This option allows you to force a module to unload, even if the
 881           kernel believes it is unsafe: the kernel will remove the module
 882           without waiting for anyone to stop using it (using the -f option to
 883           rmmod).  This is mainly for kernel developers and desperate users.
 884           If unsure, say N.
 885
 886 config MODVERSIONS
 887         bool "Module versioning support"
 888         help
 889           Usually, you have to use modules compiled with your kernel.
 890           Saying Y here makes it sometimes possible to use modules
 891           compiled for different kernels, by adding enough information
 892           to the modules to (hopefully) spot any changes which would
 893           make them incompatible with the kernel you are running.  If
 894           unsure, say N.
 895
 896 config MODULE_SRCVERSION_ALL
 897         bool "Source checksum for all modules"
 898         help
 899           Modules which contain a MODULE_VERSION get an extra "srcversion"
 900           field inserted into their modinfo section, which contains a
 901           sum of the source files which made it.  This helps maintainers
 902           see exactly which source was used to build a module (since
 903           others sometimes change the module source without updating
 904           the version).  With this option, such a "srcversion" field
 905           will be created for all modules.  If unsure, say N.
 906
 907 config KMOD
 908         def_bool y
 909         help
 910           This is being removed soon.  These days, CONFIG_MODULES
 911           implies CONFIG_KMOD, so use that instead.
 912
 913 endif # MODULES
 914
 915 config STOP_MACHINE
 916         bool
 917         default y
 918         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
 919         help
 920           Need stop_machine() primitive.
 921
 922 source "block/Kconfig"
 923
 924 config PREEMPT_NOTIFIERS
 925         bool
 926
 927 config CLASSIC_RCU
 928         def_bool !PREEMPT_RCU
 929         help
 930           This option selects the classic RCU implementation that is
 931           designed for best read-side performance on non-realtime
 932           systems.  Classic RCU is the default.  Note that the
 933           PREEMPT_RCU symbol is used to select/deselect this option.