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  42           drivers that have been replaced by something else, and/or are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_DEVICE
 303         bool "Device controller for cgroups"
 304         depends on CGROUPS && EXPERIMENTAL
 305         help
 306           Provides a cgroup implementing whitelists for devices which
 307           a process in the cgroup can mknod or open.
 308
 309 config CPUSETS
 310         bool "Cpuset support"
 311         depends on SMP && CGROUPS
 312         help
 313           This option will let you create and manage CPUSETs which
 314           allow dynamically partitioning a system into sets of CPUs and
 315           Memory Nodes and assigning tasks to run only within those sets.
 316           This is primarily useful on large SMP or NUMA systems.
 317
 318           Say N if unsure.
 319
 320 #
 321 # Architectures with an unreliable sched_clock() should select this:
 322 #
 323 config HAVE_UNSTABLE_SCHED_CLOCK
 324         bool
 325
 326 config GROUP_SCHED
 327         bool "Group CPU scheduler"
 328         depends on EXPERIMENTAL
 329         default n
 330         help
 331           This feature lets CPU scheduler recognize task groups and control CPU
 332           bandwidth allocation to such task groups.
 333
 334 config FAIR_GROUP_SCHED
 335         bool "Group scheduling for SCHED_OTHER"
 336         depends on GROUP_SCHED
 337         default GROUP_SCHED
 338
 339 config RT_GROUP_SCHED
 340         bool "Group scheduling for SCHED_RR/FIFO"
 341         depends on EXPERIMENTAL
 342         depends on GROUP_SCHED
 343         default n
 344         help
 345           This feature lets you explicitly allocate real CPU bandwidth
 346           to users or control groups (depending on the "Basis for grouping tasks"
 347           setting below. If enabled, it will also make it impossible to
 348           schedule realtime tasks for non-root users until you allocate
 349           realtime bandwidth for them.
 350           See Documentation/sched-rt-group.txt for more information.
 351
 352 choice
 353         depends on GROUP_SCHED
 354         prompt "Basis for grouping tasks"
 355         default USER_SCHED
 356
 357 config USER_SCHED
 358         bool "user id"
 359         help
 360           This option will choose userid as the basis for grouping
 361           tasks, thus providing equal CPU bandwidth to each user.
 362
 363 config CGROUP_SCHED
 364         bool "Control groups"
 365         depends on CGROUPS
 366         help
 367           This option allows you to create arbitrary task groups
 368           using the "cgroup" pseudo filesystem and control
 369           the cpu bandwidth allocated to each such task group.
 370           Refer to Documentation/cgroups.txt for more information
 371           on "cgroup" pseudo filesystem.
 372
 373 endchoice
 374
 375 config CGROUP_CPUACCT
 376         bool "Simple CPU accounting cgroup subsystem"
 377         depends on CGROUPS
 378         help
 379           Provides a simple Resource Controller for monitoring the
 380           total CPU consumed by the tasks in a cgroup
 381
 382 config RESOURCE_COUNTERS
 383         bool "Resource counters"
 384         help
 385           This option enables controller independent resource accounting
 386           infrastructure that works with cgroups
 387         depends on CGROUPS
 388
 389 config MM_OWNER
 390         bool
 391
 392 config CGROUP_MEM_RES_CTLR
 393         bool "Memory Resource Controller for Control Groups"
 394         depends on CGROUPS && RESOURCE_COUNTERS
 395         select MM_OWNER
 396         help
 397           Provides a memory resource controller that manages both page cache and
 398           RSS memory.
 399
 400           Note that setting this option increases fixed memory overhead
 401           associated with each page of memory in the system by 4/8 bytes
 402           and also increases cache misses because struct page on many 64bit
 403           systems will not fit into a single cache line anymore.
 404
 405           Only enable when you're ok with these trade offs and really
 406           sure you need the memory resource controller.
 407
 408           This config option also selects MM_OWNER config option, which
 409           could in turn add some fork/exit overhead.
 410
 411 config SYSFS_DEPRECATED
 412         bool
 413
 414 config SYSFS_DEPRECATED_V2
 415         bool "Create deprecated sysfs files"
 416         depends on SYSFS
 417         default y
 418         select SYSFS_DEPRECATED
 419         help
 420           This option creates deprecated symlinks such as the
 421           "device"-link, the <subsystem>:<name>-link, and the
 422           "bus"-link. It may also add deprecated key in the
 423           uevent environment.
 424           None of these features or values should be used today, as
 425           they export driver core implementation details to userspace
 426           or export properties which can't be kept stable across kernel
 427           releases.
 428
 429           If enabled, this option will also move any device structures
 430           that belong to a class, back into the /sys/class hierarchy, in
 431           order to support older versions of udev and some userspace
 432           programs.
 433
 434           If you are using a distro with the most recent userspace
 435           packages, it should be safe to say N here.
 436
 437 config PROC_PID_CPUSET
 438         bool "Include legacy /proc/<pid>/cpuset file"
 439         depends on CPUSETS
 440         default y
 441
 442 config RELAY
 443         bool "Kernel->user space relay support (formerly relayfs)"
 444         help
 445           This option enables support for relay interface support in
 446           certain file systems (such as debugfs).
 447           It is designed to provide an efficient mechanism for tools and
 448           facilities to relay large amounts of data from kernel space to
 449           user space.
 450
 451           If unsure, say N.
 452
 453 config NAMESPACES
 454         bool "Namespaces support" if EMBEDDED
 455         default !EMBEDDED
 456         help
 457           Provides the way to make tasks work with different objects using
 458           the same id. For example same IPC id may refer to different objects
 459           or same user id or pid may refer to different tasks when used in
 460           different namespaces.
 461
 462 config UTS_NS
 463         bool "UTS namespace"
 464         depends on NAMESPACES
 465         help
 466           In this namespace tasks see different info provided with the
 467           uname() system call
 468
 469 config IPC_NS
 470         bool "IPC namespace"
 471         depends on NAMESPACES && SYSVIPC
 472         help
 473           In this namespace tasks work with IPC ids which correspond to
 474           different IPC objects in different namespaces
 475
 476 config USER_NS
 477         bool "User namespace (EXPERIMENTAL)"
 478         depends on NAMESPACES && EXPERIMENTAL
 479         help
 480           This allows containers, i.e. vservers, to use user namespaces
 481           to provide different user info for different servers.
 482           If unsure, say N.
 483
 484 config PID_NS
 485         bool "PID Namespaces (EXPERIMENTAL)"
 486         default n
 487         depends on NAMESPACES && EXPERIMENTAL
 488         help
 489           Support process id namespaces.  This allows having multiple
 490           process with the same pid as long as they are in different
 491           pid namespaces.  This is a building block of containers.
 492
 493           Unless you want to work with an experimental feature
 494           say N here.
 495
 496 config BLK_DEV_INITRD
 497         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 498         depends on BROKEN || !FRV
 499         help
 500           The initial RAM filesystem is a ramfs which is loaded by the
 501           boot loader (loadlin or lilo) and that is mounted as root
 502           before the normal boot procedure. It is typically used to
 503           load modules needed to mount the "real" root file system,
 504           etc. See <file:Documentation/initrd.txt> for details.
 505
 506           If RAM disk support (BLK_DEV_RAM) is also included, this
 507           also enables initial RAM disk (initrd) support and adds
 508           15 Kbytes (more on some other architectures) to the kernel size.
 509
 510           If unsure say Y.
 511
 512 if BLK_DEV_INITRD
 513
 514 source "usr/Kconfig"
 515
 516 endif
 517
 518 config CC_OPTIMIZE_FOR_SIZE
 519         bool "Optimize for size"
 520         default y
 521         help
 522           Enabling this option will pass "-Os" instead of "-O2" to gcc
 523           resulting in a smaller kernel.
 524
 525           If unsure, say Y.
 526
 527 config SYSCTL
 528         bool
 529
 530 menuconfig EMBEDDED
 531         bool "Configure standard kernel features (for small systems)"
 532         help
 533           This option allows certain base kernel options and settings
 534           to be disabled or tweaked. This is for specialized
 535           environments which can tolerate a "non-standard" kernel.
 536           Only use this if you really know what you are doing.
 537
 538 config UID16
 539         bool "Enable 16-bit UID system calls" if EMBEDDED
 540         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 541         default y
 542         help
 543           This enables the legacy 16-bit UID syscall wrappers.
 544
 545 config SYSCTL_SYSCALL
 546         bool "Sysctl syscall support" if EMBEDDED
 547         default y
 548         select SYSCTL
 549         ---help---
 550           sys_sysctl uses binary paths that have been found challenging
 551           to properly maintain and use.  The interface in /proc/sys
 552           using paths with ascii names is now the primary path to this
 553           information.
 554
 555           Almost nothing using the binary sysctl interface so if you are
 556           trying to save some space it is probably safe to disable this,
 557           making your kernel marginally smaller.
 558
 559           If unsure say Y here.
 560
 561 config KALLSYMS
 562          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 563          default y
 564          help
 565            Say Y here to let the kernel print out symbolic crash information and
 566            symbolic stack backtraces. This increases the size of the kernel
 567            somewhat, as all symbols have to be loaded into the kernel image.
 568
 569 config KALLSYMS_ALL
 570         bool "Include all symbols in kallsyms"
 571         depends on DEBUG_KERNEL && KALLSYMS
 572         help
 573            Normally kallsyms only contains the symbols of functions, for nicer
 574            OOPS messages.  Some debuggers can use kallsyms for other
 575            symbols too: say Y here to include all symbols, if you need them
 576            and you don't care about adding 300k to the size of your kernel.
 577
 578            Say N.
 579
 580 config KALLSYMS_EXTRA_PASS
 581         bool "Do an extra kallsyms pass"
 582         depends on KALLSYMS
 583         help
 584            If kallsyms is not working correctly, the build will fail with
 585            inconsistent kallsyms data.  If that occurs, log a bug report and
 586            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 587            Always say N here unless you find a bug in kallsyms, which must be
 588            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 589            you wait for kallsyms to be fixed.
 590
 591
 592 config HOTPLUG
 593         bool "Support for hot-pluggable devices" if EMBEDDED
 594         default y
 595         help
 596           This option is provided for the case where no hotplug or uevent
 597           capabilities is wanted by the kernel.  You should only consider
 598           disabling this option for embedded systems that do not use modules, a
 599           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 600
 601 config PRINTK
 602         default y
 603         bool "Enable support for printk" if EMBEDDED
 604         help
 605           This option enables normal printk support. Removing it
 606           eliminates most of the message strings from the kernel image
 607           and makes the kernel more or less silent. As this makes it
 608           very difficult to diagnose system problems, saying N here is
 609           strongly discouraged.
 610
 611 config BUG
 612         bool "BUG() support" if EMBEDDED
 613         default y
 614         help
 615           Disabling this option eliminates support for BUG and WARN, reducing
 616           the size of your kernel image and potentially quietly ignoring
 617           numerous fatal conditions. You should only consider disabling this
 618           option for embedded systems with no facilities for reporting errors.
 619           Just say Y.
 620
 621 config ELF_CORE
 622         default y
 623         bool "Enable ELF core dumps" if EMBEDDED
 624         help
 625           Enable support for generating core dumps. Disabling saves about 4k.
 626
 627 config PCSPKR_PLATFORM
 628         bool "Enable PC-Speaker support" if EMBEDDED
 629         depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
 630         default y
 631         help
 632           This option allows to disable the internal PC-Speaker
 633           support, saving some memory.
 634
 635 config COMPAT_BRK
 636         bool "Disable heap randomization"
 637         default y
 638         help
 639           Randomizing heap placement makes heap exploits harder, but it
 640           also breaks ancient binaries (including anything libc5 based).
 641           This option changes the bootup default to heap randomization
 642           disabled, and can be overriden runtime by setting
 643           /proc/sys/kernel/randomize_va_space to 2.
 644
 645           On non-ancient distros (post-2000 ones) N is usually a safe choice.
 646
 647 config BASE_FULL
 648         default y
 649         bool "Enable full-sized data structures for core" if EMBEDDED
 650         help
 651           Disabling this option reduces the size of miscellaneous core
 652           kernel data structures. This saves memory on small machines,
 653           but may reduce performance.
 654
 655 config FUTEX
 656         bool "Enable futex support" if EMBEDDED
 657         default y
 658         select RT_MUTEXES
 659         help
 660           Disabling this option will cause the kernel to be built without
 661           support for "fast userspace mutexes".  The resulting kernel may not
 662           run glibc-based applications correctly.
 663
 664 config ANON_INODES
 665         bool
 666
 667 config EPOLL
 668         bool "Enable eventpoll support" if EMBEDDED
 669         default y
 670         select ANON_INODES
 671         help
 672           Disabling this option will cause the kernel to be built without
 673           support for epoll family of system calls.
 674
 675 config SIGNALFD
 676         bool "Enable signalfd() system call" if EMBEDDED
 677         select ANON_INODES
 678         default y
 679         help
 680           Enable the signalfd() system call that allows to receive signals
 681           on a file descriptor.
 682
 683           If unsure, say Y.
 684
 685 config TIMERFD
 686         bool "Enable timerfd() system call" if EMBEDDED
 687         select ANON_INODES
 688         default y
 689         help
 690           Enable the timerfd() system call that allows to receive timer
 691           events on a file descriptor.
 692
 693           If unsure, say Y.
 694
 695 config EVENTFD
 696         bool "Enable eventfd() system call" if EMBEDDED
 697         select ANON_INODES
 698         default y
 699         help
 700           Enable the eventfd() system call that allows to receive both
 701           kernel notification (ie. KAIO) or userspace notifications.
 702
 703           If unsure, say Y.
 704
 705 config SHMEM
 706         bool "Use full shmem filesystem" if EMBEDDED
 707         default y
 708         depends on MMU
 709         help
 710           The shmem is an internal filesystem used to manage shared memory.
 711           It is backed by swap and manages resource limits. It is also exported
 712           to userspace as tmpfs if TMPFS is enabled. Disabling this
 713           option replaces shmem and tmpfs with the much simpler ramfs code,
 714           which may be appropriate on small systems without swap.
 715
 716 config VM_EVENT_COUNTERS
 717         default y
 718         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
 719         help
 720           VM event counters are needed for event counts to be shown.
 721           This option allows the disabling of the VM event counters
 722           on EMBEDDED systems.  /proc/vmstat will only show page counts
 723           if VM event counters are disabled.
 724
 725 config SLUB_DEBUG
 726         default y
 727         bool "Enable SLUB debugging support" if EMBEDDED
 728         depends on SLUB && SYSFS
 729         help
 730           SLUB has extensive debug support features. Disabling these can
 731           result in significant savings in code size. This also disables
 732           SLUB sysfs support. /sys/slab will not exist and there will be
 733           no support for cache validation etc.
 734
 735 choice
 736         prompt "Choose SLAB allocator"
 737         default SLUB
 738         help
 739            This option allows to select a slab allocator.
 740
 741 config SLAB
 742         bool "SLAB"
 743         help
 744           The regular slab allocator that is established and known to work
 745           well in all environments. It organizes cache hot objects in
 746           per cpu and per node queues. SLAB is the default choice for
 747           a slab allocator.
 748
 749 config SLUB
 750         bool "SLUB (Unqueued Allocator)"
 751         help
 752            SLUB is a slab allocator that minimizes cache line usage
 753            instead of managing queues of cached objects (SLAB approach).
 754            Per cpu caching is realized using slabs of objects instead
 755            of queues of objects. SLUB can use memory efficiently
 756            and has enhanced diagnostics.
 757
 758 config SLOB
 759         depends on EMBEDDED
 760         bool "SLOB (Simple Allocator)"
 761         help
 762            SLOB replaces the stock allocator with a drastically simpler
 763            allocator. SLOB is generally more space efficient but
 764            does not perform as well on large systems.
 765
 766 endchoice
 767
 768 config PROFILING
 769         bool "Profiling support (EXPERIMENTAL)"
 770         help
 771           Say Y here to enable the extended profiling support mechanisms used
 772           by profilers such as OProfile.
 773
 774 config MARKERS
 775         bool "Activate markers"
 776         help
 777           Place an empty function call at each marker site. Can be
 778           dynamically changed for a probe function.
 779
 780 source "arch/Kconfig"
 781
 782 config PROC_PAGE_MONITOR
 783         default y
 784         depends on PROC_FS && MMU
 785         bool "Enable /proc page monitoring" if EMBEDDED
 786         help
 787           Various /proc files exist to monitor process memory utilization:
 788           /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
 789           /proc/kpagecount, and /proc/kpageflags. Disabling these
 790           interfaces will reduce the size of the kernel by approximately 4kb.
 791
 792 endmenu         # General setup
 793
 794 config HAVE_GENERIC_DMA_COHERENT
 795         bool
 796         default n
 797
 798 config SLABINFO
 799         bool
 800         depends on PROC_FS
 801         depends on SLAB || SLUB_DEBUG
 802         default y
 803
 804 config RT_MUTEXES
 805         boolean
 806         select PLIST
 807
 808 config TINY_SHMEM
 809         default !SHMEM
 810         bool
 811
 812 config BASE_SMALL
 813         int
 814         default 0 if BASE_FULL
 815         default 1 if !BASE_FULL
 816
 817 menuconfig MODULES
 818         bool "Enable loadable module support"
 819         help
 820           Kernel modules are small pieces of compiled code which can
 821           be inserted in the running kernel, rather than being
 822           permanently built into the kernel.  You use the "modprobe"
 823           tool to add (and sometimes remove) them.  If you say Y here,
 824           many parts of the kernel can be built as modules (by
 825           answering M instead of Y where indicated): this is most
 826           useful for infrequently used options which are not required
 827           for booting.  For more information, see the man pages for
 828           modprobe, lsmod, modinfo, insmod and rmmod.
 829
 830           If you say Y here, you will need to run "make
 831           modules_install" to put the modules under /lib/modules/
 832           where modprobe can find them (you may need to be root to do
 833           this).
 834
 835           If unsure, say Y.
 836
 837 if MODULES
 838
 839 config MODULE_FORCE_LOAD
 840         bool "Forced module loading"
 841         default n
 842         help
 843           Allow loading of modules without version information (ie. modprobe
 844           --force).  Forced module loading sets the 'F' (forced) taint flag and
 845           is usually a really bad idea.
 846
 847 config MODULE_UNLOAD
 848         bool "Module unloading"
 849         help
 850           Without this option you will not be able to unload any
 851           modules (note that some modules may not be unloadable
 852           anyway), which makes your kernel smaller, faster
 853           and simpler.  If unsure, say Y.
 854
 855 config MODULE_FORCE_UNLOAD
 856         bool "Forced module unloading"
 857         depends on MODULE_UNLOAD && EXPERIMENTAL
 858         help
 859           This option allows you to force a module to unload, even if the
 860           kernel believes it is unsafe: the kernel will remove the module
 861           without waiting for anyone to stop using it (using the -f option to
 862           rmmod).  This is mainly for kernel developers and desperate users.
 863           If unsure, say N.
 864
 865 config MODVERSIONS
 866         bool "Module versioning support"
 867         help
 868           Usually, you have to use modules compiled with your kernel.
 869           Saying Y here makes it sometimes possible to use modules
 870           compiled for different kernels, by adding enough information
 871           to the modules to (hopefully) spot any changes which would
 872           make them incompatible with the kernel you are running.  If
 873           unsure, say N.
 874
 875 config MODULE_SRCVERSION_ALL
 876         bool "Source checksum for all modules"
 877         help
 878           Modules which contain a MODULE_VERSION get an extra "srcversion"
 879           field inserted into their modinfo section, which contains a
 880           sum of the source files which made it.  This helps maintainers
 881           see exactly which source was used to build a module (since
 882           others sometimes change the module source without updating
 883           the version).  With this option, such a "srcversion" field
 884           will be created for all modules.  If unsure, say N.
 885
 886 config KMOD
 887         def_bool y
 888         help
 889           This is being removed soon.  These days, CONFIG_MODULES
 890           implies CONFIG_KMOD, so use that instead.
 891
 892 endif # MODULES
 893
 894 config STOP_MACHINE
 895         bool
 896         default y
 897         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
 898         help
 899           Need stop_machine() primitive.
 900
 901 source "block/Kconfig"
 902
 903 config PREEMPT_NOTIFIERS
 904         bool
 905
 906 config CLASSIC_RCU
 907         def_bool !PREEMPT_RCU
 908         help
 909           This option selects the classic RCU implementation that is
 910           designed for best read-side performance on non-realtime
 911           systems.  Classic RCU is the default.  Note that the
 912           PREEMPT_RCU symbol is used to select/deselect this option.