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 config CONSTRUCTORS
  20         bool
  21         depends on !UML
  22
  23 config HAVE_IRQ_WORK
  24         bool
  25
  26 config IRQ_WORK
  27         bool
  28         depends on HAVE_IRQ_WORK
  29
  30 menu "General setup"
  31
  32 config EXPERIMENTAL
  33         bool "Prompt for development and/or incomplete code/drivers"
  34         ---help---
  35           Some of the various things that Linux supports (such as network
  36           drivers, file systems, network protocols, etc.) can be in a state
  37           of development where the functionality, stability, or the level of
  38           testing is not yet high enough for general use. This is usually
  39           known as the "alpha-test" phase among developers. If a feature is
  40           currently in alpha-test, then the developers usually discourage
  41           uninformed widespread use of this feature by the general public to
  42           avoid "Why doesn't this work?" type mail messages. However, active
  43           testing and use of these systems is welcomed. Just be aware that it
  44           may not meet the normal level of reliability or it may fail to work
  45           in some special cases. Detailed bug reports from people familiar
  46           with the kernel internals are usually welcomed by the developers
  47           (before submitting bug reports, please read the documents
  48           <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  49           <file:Documentation/BUG-HUNTING>, and
  50           <file:Documentation/oops-tracing.txt> in the kernel source).
  51
  52           This option will also make obsoleted drivers available. These are
  53           drivers that have been replaced by something else, and/or are
  54           scheduled to be removed in a future kernel release.
  55
  56           Unless you intend to help test and develop a feature or driver that
  57           falls into this category, or you have a situation that requires
  58           using these features, you should probably say N here, which will
  59           cause the configurator to present you with fewer choices. If
  60           you say Y here, you will be offered the choice of using features or
  61           drivers that are currently considered to be in the alpha-test phase.
  62
  63 config BROKEN
  64         bool
  65
  66 config BROKEN_ON_SMP
  67         bool
  68         depends on BROKEN || !SMP
  69         default y
  70
  71 config INIT_ENV_ARG_LIMIT
  72         int
  73         default 32 if !UML
  74         default 128 if UML
  75         help
  76           Maximum of each of the number of arguments and environment
  77           variables passed to init from the kernel command line.
  78
  79
  80 config CROSS_COMPILE
  81         string "Cross-compiler tool prefix"
  82         help
  83           Same as running 'make CROSS_COMPILE=prefix-' but stored for
  84           default make runs in this kernel build directory.  You don't
  85           need to set this unless you want the configured kernel build
  86           directory to select the cross-compiler automatically.
  87
  88 config LOCALVERSION
  89         string "Local version - append to kernel release"
  90         help
  91           Append an extra string to the end of your kernel version.
  92           This will show up when you type uname, for example.
  93           The string you set here will be appended after the contents of
  94           any files with a filename matching localversion* in your
  95           object and source tree, in that order.  Your total string can
  96           be a maximum of 64 characters.
  97
  98 config LOCALVERSION_AUTO
  99         bool "Automatically append version information to the version string"
 100         default y
 101         help
 102           This will try to automatically determine if the current tree is a
 103           release tree by looking for git tags that belong to the current
 104           top of tree revision.
 105
 106           A string of the format -gxxxxxxxx will be added to the localversion
 107           if a git-based tree is found.  The string generated by this will be
 108           appended after any matching localversion* files, and after the value
 109           set in CONFIG_LOCALVERSION.
 110
 111           (The actual string used here is the first eight characters produced
 112           by running the command:
 113
 114             $ git rev-parse --verify HEAD
 115
 116           which is done within the script "scripts/setlocalversion".)
 117
 118 config HAVE_KERNEL_GZIP
 119         bool
 120
 121 config HAVE_KERNEL_BZIP2
 122         bool
 123
 124 config HAVE_KERNEL_LZMA
 125         bool
 126
 127 config HAVE_KERNEL_XZ
 128         bool
 129
 130 config HAVE_KERNEL_LZO
 131         bool
 132
 133 choice
 134         prompt "Kernel compression mode"
 135         default KERNEL_GZIP
 136         depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
 137         help
 138           The linux kernel is a kind of self-extracting executable.
 139           Several compression algorithms are available, which differ
 140           in efficiency, compression and decompression speed.
 141           Compression speed is only relevant when building a kernel.
 142           Decompression speed is relevant at each boot.
 143
 144           If you have any problems with bzip2 or lzma compressed
 145           kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
 146           version of this functionality (bzip2 only), for 2.4, was
 147           supplied by Christian Ludwig)
 148
 149           High compression options are mostly useful for users, who
 150           are low on disk space (embedded systems), but for whom ram
 151           size matters less.
 152
 153           If in doubt, select 'gzip'
 154
 155 config KERNEL_GZIP
 156         bool "Gzip"
 157         depends on HAVE_KERNEL_GZIP
 158         help
 159           The old and tried gzip compression. It provides a good balance
 160           between compression ratio and decompression speed.
 161
 162 config KERNEL_BZIP2
 163         bool "Bzip2"
 164         depends on HAVE_KERNEL_BZIP2
 165         help
 166           Its compression ratio and speed is intermediate.
 167           Decompression speed is slowest among the three.  The kernel
 168           size is about 10% smaller with bzip2, in comparison to gzip.
 169           Bzip2 uses a large amount of memory. For modern kernels you
 170           will need at least 8MB RAM or more for booting.
 171
 172 config KERNEL_LZMA
 173         bool "LZMA"
 174         depends on HAVE_KERNEL_LZMA
 175         help
 176           The most recent compression algorithm.
 177           Its ratio is best, decompression speed is between the other
 178           two. Compression is slowest.  The kernel size is about 33%
 179           smaller with LZMA in comparison to gzip.
 180
 181 config KERNEL_XZ
 182         bool "XZ"
 183         depends on HAVE_KERNEL_XZ
 184         help
 185           XZ uses the LZMA2 algorithm and instruction set specific
 186           BCJ filters which can improve compression ratio of executable
 187           code. The size of the kernel is about 30% smaller with XZ in
 188           comparison to gzip. On architectures for which there is a BCJ
 189           filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
 190           will create a few percent smaller kernel than plain LZMA.
 191
 192           The speed is about the same as with LZMA: The decompression
 193           speed of XZ is better than that of bzip2 but worse than gzip
 194           and LZO. Compression is slow.
 195
 196 config KERNEL_LZO
 197         bool "LZO"
 198         depends on HAVE_KERNEL_LZO
 199         help
 200           Its compression ratio is the poorest among the 4. The kernel
 201           size is about 10% bigger than gzip; however its speed
 202           (both compression and decompression) is the fastest.
 203
 204 endchoice
 205
 206 config DEFAULT_HOSTNAME
 207         string "Default hostname"
 208         default "(none)"
 209         help
 210           This option determines the default system hostname before userspace
 211           calls sethostname(2). The kernel traditionally uses "(none)" here,
 212           but you may wish to use a different default here to make a minimal
 213           system more usable with less configuration.
 214
 215 config SWAP
 216         bool "Support for paging of anonymous memory (swap)"
 217         depends on MMU && BLOCK
 218         default y
 219         help
 220           This option allows you to choose whether you want to have support
 221           for so called swap devices or swap files in your kernel that are
 222           used to provide more virtual memory than the actual RAM present
 223           in your computer.  If unsure say Y.
 224
 225 config SYSVIPC
 226         bool "System V IPC"
 227         ---help---
 228           Inter Process Communication is a suite of library functions and
 229           system calls which let processes (running programs) synchronize and
 230           exchange information. It is generally considered to be a good thing,
 231           and some programs won't run unless you say Y here. In particular, if
 232           you want to run the DOS emulator dosemu under Linux (read the
 233           DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 234           you'll need to say Y here.
 235
 236           You can find documentation about IPC with "info ipc" and also in
 237           section 6.4 of the Linux Programmer's Guide, available from
 238           <http://www.tldp.org/guides.html>.
 239
 240 config SYSVIPC_SYSCTL
 241         bool
 242         depends on SYSVIPC
 243         depends on SYSCTL
 244         default y
 245
 246 config POSIX_MQUEUE
 247         bool "POSIX Message Queues"
 248         depends on NET && EXPERIMENTAL
 249         ---help---
 250           POSIX variant of message queues is a part of IPC. In POSIX message
 251           queues every message has a priority which decides about succession
 252           of receiving it by a process. If you want to compile and run
 253           programs written e.g. for Solaris with use of its POSIX message
 254           queues (functions mq_*) say Y here.
 255
 256           POSIX message queues are visible as a filesystem called 'mqueue'
 257           and can be mounted somewhere if you want to do filesystem
 258           operations on message queues.
 259
 260           If unsure, say Y.
 261
 262 config POSIX_MQUEUE_SYSCTL
 263         bool
 264         depends on POSIX_MQUEUE
 265         depends on SYSCTL
 266         default y
 267
 268 config BSD_PROCESS_ACCT
 269         bool "BSD Process Accounting"
 270         help
 271           If you say Y here, a user level program will be able to instruct the
 272           kernel (via a special system call) to write process accounting
 273           information to a file: whenever a process exits, information about
 274           that process will be appended to the file by the kernel.  The
 275           information includes things such as creation time, owning user,
 276           command name, memory usage, controlling terminal etc. (the complete
 277           list is in the struct acct in <file:include/linux/acct.h>).  It is
 278           up to the user level program to do useful things with this
 279           information.  This is generally a good idea, so say Y.
 280
 281 config BSD_PROCESS_ACCT_V3
 282         bool "BSD Process Accounting version 3 file format"
 283         depends on BSD_PROCESS_ACCT
 284         default n
 285         help
 286           If you say Y here, the process accounting information is written
 287           in a new file format that also logs the process IDs of each
 288           process and it's parent. Note that this file format is incompatible
 289           with previous v0/v1/v2 file formats, so you will need updated tools
 290           for processing it. A preliminary version of these tools is available
 291           at <http://www.gnu.org/software/acct/>.
 292
 293 config FHANDLE
 294         bool "open by fhandle syscalls"
 295         select EXPORTFS
 296         help
 297           If you say Y here, a user level program will be able to map
 298           file names to handle and then later use the handle for
 299           different file system operations. This is useful in implementing
 300           userspace file servers, which now track files using handles instead
 301           of names. The handle would remain the same even if file names
 302           get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
 303           syscalls.
 304
 305 config TASKSTATS
 306         bool "Export task/process statistics through netlink (EXPERIMENTAL)"
 307         depends on NET
 308         default n
 309         help
 310           Export selected statistics for tasks/processes through the
 311           generic netlink interface. Unlike BSD process accounting, the
 312           statistics are available during the lifetime of tasks/processes as
 313           responses to commands. Like BSD accounting, they are sent to user
 314           space on task exit.
 315
 316           Say N if unsure.
 317
 318 config TASK_DELAY_ACCT
 319         bool "Enable per-task delay accounting (EXPERIMENTAL)"
 320         depends on TASKSTATS
 321         help
 322           Collect information on time spent by a task waiting for system
 323           resources like cpu, synchronous block I/O completion and swapping
 324           in pages. Such statistics can help in setting a task's priorities
 325           relative to other tasks for cpu, io, rss limits etc.
 326
 327           Say N if unsure.
 328
 329 config TASK_XACCT
 330         bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
 331         depends on TASKSTATS
 332         help
 333           Collect extended task accounting data and send the data
 334           to userland for processing over the taskstats interface.
 335
 336           Say N if unsure.
 337
 338 config TASK_IO_ACCOUNTING
 339         bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
 340         depends on TASK_XACCT
 341         help
 342           Collect information on the number of bytes of storage I/O which this
 343           task has caused.
 344
 345           Say N if unsure.
 346
 347 config AUDIT
 348         bool "Auditing support"
 349         depends on NET
 350         help
 351           Enable auditing infrastructure that can be used with another
 352           kernel subsystem, such as SELinux (which requires this for
 353           logging of avc messages output).  Does not do system-call
 354           auditing without CONFIG_AUDITSYSCALL.
 355
 356 config AUDITSYSCALL
 357         bool "Enable system-call auditing support"
 358         depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
 359         default y if SECURITY_SELINUX
 360         help
 361           Enable low-overhead system-call auditing infrastructure that
 362           can be used independently or with another kernel subsystem,
 363           such as SELinux.
 364
 365 config AUDIT_WATCH
 366         def_bool y
 367         depends on AUDITSYSCALL
 368         select FSNOTIFY
 369
 370 config AUDIT_TREE
 371         def_bool y
 372         depends on AUDITSYSCALL
 373         select FSNOTIFY
 374
 375 config AUDIT_LOGINUID_IMMUTABLE
 376         bool "Make audit loginuid immutable"
 377         depends on AUDIT
 378         help
 379           The config option toggles if a task setting its loginuid requires
 380           CAP_SYS_AUDITCONTROL or if that task should require no special permissions
 381           but should instead only allow setting its loginuid if it was never
 382           previously set.  On systems which use systemd or a similar central
 383           process to restart login services this should be set to true.  On older
 384           systems in which an admin would typically have to directly stop and
 385           start processes this should be set to false.  Setting this to true allows
 386           one to drop potentially dangerous capabilites from the login tasks,
 387           but may not be backwards compatible with older init systems.
 388
 389 source "kernel/irq/Kconfig"
 390
 391 menu "RCU Subsystem"
 392
 393 choice
 394         prompt "RCU Implementation"
 395         default TREE_RCU
 396
 397 config TREE_RCU
 398         bool "Tree-based hierarchical RCU"
 399         depends on !PREEMPT && SMP
 400         help
 401           This option selects the RCU implementation that is
 402           designed for very large SMP system with hundreds or
 403           thousands of CPUs.  It also scales down nicely to
 404           smaller systems.
 405
 406 config TREE_PREEMPT_RCU
 407         bool "Preemptible tree-based hierarchical RCU"
 408         depends on PREEMPT && SMP
 409         help
 410           This option selects the RCU implementation that is
 411           designed for very large SMP systems with hundreds or
 412           thousands of CPUs, but for which real-time response
 413           is also required.  It also scales down nicely to
 414           smaller systems.
 415
 416 config TINY_RCU
 417         bool "UP-only small-memory-footprint RCU"
 418         depends on !PREEMPT && !SMP
 419         help
 420           This option selects the RCU implementation that is
 421           designed for UP systems from which real-time response
 422           is not required.  This option greatly reduces the
 423           memory footprint of RCU.
 424
 425 config TINY_PREEMPT_RCU
 426         bool "Preemptible UP-only small-memory-footprint RCU"
 427         depends on PREEMPT && !SMP
 428         help
 429           This option selects the RCU implementation that is designed
 430           for real-time UP systems.  This option greatly reduces the
 431           memory footprint of RCU.
 432
 433 endchoice
 434
 435 config PREEMPT_RCU
 436         def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
 437         help
 438           This option enables preemptible-RCU code that is common between
 439           the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
 440
 441 config RCU_TRACE
 442         bool "Enable tracing for RCU"
 443         help
 444           This option provides tracing in RCU which presents stats
 445           in debugfs for debugging RCU implementation.
 446
 447           Say Y here if you want to enable RCU tracing
 448           Say N if you are unsure.
 449
 450 config RCU_FANOUT
 451         int "Tree-based hierarchical RCU fanout value"
 452         range 2 64 if 64BIT
 453         range 2 32 if !64BIT
 454         depends on TREE_RCU || TREE_PREEMPT_RCU
 455         default 64 if 64BIT
 456         default 32 if !64BIT
 457         help
 458           This option controls the fanout of hierarchical implementations
 459           of RCU, allowing RCU to work efficiently on machines with
 460           large numbers of CPUs.  This value must be at least the fourth
 461           root of NR_CPUS, which allows NR_CPUS to be insanely large.
 462           The default value of RCU_FANOUT should be used for production
 463           systems, but if you are stress-testing the RCU implementation
 464           itself, small RCU_FANOUT values allow you to test large-system
 465           code paths on small(er) systems.
 466
 467           Select a specific number if testing RCU itself.
 468           Take the default if unsure.
 469
 470 config RCU_FANOUT_EXACT
 471         bool "Disable tree-based hierarchical RCU auto-balancing"
 472         depends on TREE_RCU || TREE_PREEMPT_RCU
 473         default n
 474         help
 475           This option forces use of the exact RCU_FANOUT value specified,
 476           regardless of imbalances in the hierarchy.  This is useful for
 477           testing RCU itself, and might one day be useful on systems with
 478           strong NUMA behavior.
 479
 480           Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 481
 482           Say N if unsure.
 483
 484 config RCU_FAST_NO_HZ
 485         bool "Accelerate last non-dyntick-idle CPU's grace periods"
 486         depends on NO_HZ && SMP
 487         default n
 488         help
 489           This option causes RCU to attempt to accelerate grace periods
 490           in order to allow CPUs to enter dynticks-idle state more
 491           quickly.  On the other hand, this option increases the overhead
 492           of the dynticks-idle checking, particularly on systems with
 493           large numbers of CPUs.
 494
 495           Say Y if energy efficiency is critically important, particularly
 496                 if you have relatively few CPUs.
 497
 498           Say N if you are unsure.
 499
 500 config TREE_RCU_TRACE
 501         def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 502         select DEBUG_FS
 503         help
 504           This option provides tracing for the TREE_RCU and
 505           TREE_PREEMPT_RCU implementations, permitting Makefile to
 506           trivially select kernel/rcutree_trace.c.
 507
 508 config RCU_BOOST
 509         bool "Enable RCU priority boosting"
 510         depends on RT_MUTEXES && PREEMPT_RCU
 511         default n
 512         help
 513           This option boosts the priority of preempted RCU readers that
 514           block the current preemptible RCU grace period for too long.
 515           This option also prevents heavy loads from blocking RCU
 516           callback invocation for all flavors of RCU.
 517
 518           Say Y here if you are working with real-time apps or heavy loads
 519           Say N here if you are unsure.
 520
 521 config RCU_BOOST_PRIO
 522         int "Real-time priority to boost RCU readers to"
 523         range 1 99
 524         depends on RCU_BOOST
 525         default 1
 526         help
 527           This option specifies the real-time priority to which preempted
 528           RCU readers are to be boosted.  If you are working with CPU-bound
 529           real-time applications, you should specify a priority higher then
 530           the highest-priority CPU-bound application.
 531
 532           Specify the real-time priority, or take the default if unsure.
 533
 534 config RCU_BOOST_DELAY
 535         int "Milliseconds to delay boosting after RCU grace-period start"
 536         range 0 3000
 537         depends on RCU_BOOST
 538         default 500
 539         help
 540           This option specifies the time to wait after the beginning of
 541           a given grace period before priority-boosting preempted RCU
 542           readers blocking that grace period.  Note that any RCU reader
 543           blocking an expedited RCU grace period is boosted immediately.
 544
 545           Accept the default if unsure.
 546
 547 endmenu # "RCU Subsystem"
 548
 549 config IKCONFIG
 550         tristate "Kernel .config support"
 551         ---help---
 552           This option enables the complete Linux kernel ".config" file
 553           contents to be saved in the kernel. It provides documentation
 554           of which kernel options are used in a running kernel or in an
 555           on-disk kernel.  This information can be extracted from the kernel
 556           image file with the script scripts/extract-ikconfig and used as
 557           input to rebuild the current kernel or to build another kernel.
 558           It can also be extracted from a running kernel by reading
 559           /proc/config.gz if enabled (below).
 560
 561 config IKCONFIG_PROC
 562         bool "Enable access to .config through /proc/config.gz"
 563         depends on IKCONFIG && PROC_FS
 564         ---help---
 565           This option enables access to the kernel configuration file
 566           through /proc/config.gz.
 567
 568 config LOG_BUF_SHIFT
 569         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 570         range 12 21
 571         default 17
 572         help
 573           Select kernel log buffer size as a power of 2.
 574           Examples:
 575                      17 => 128 KB
 576                      16 => 64 KB
 577                      15 => 32 KB
 578                      14 => 16 KB
 579                      13 =>  8 KB
 580                      12 =>  4 KB
 581
 582 #
 583 # Architectures with an unreliable sched_clock() should select this:
 584 #
 585 config HAVE_UNSTABLE_SCHED_CLOCK
 586         bool
 587
 588 menuconfig CGROUPS
 589         boolean "Control Group support"
 590         depends on EVENTFD
 591         help
 592           This option adds support for grouping sets of processes together, for
 593           use with process control subsystems such as Cpusets, CFS, memory
 594           controls or device isolation.
 595           See
 596                 - Documentation/scheduler/sched-design-CFS.txt  (CFS)
 597                 - Documentation/cgroups/ (features for grouping, isolation
 598                                           and resource control)
 599
 600           Say N if unsure.
 601
 602 if CGROUPS
 603
 604 config CGROUP_DEBUG
 605         bool "Example debug cgroup subsystem"
 606         default n
 607         help
 608           This option enables a simple cgroup subsystem that
 609           exports useful debugging information about the cgroups
 610           framework.
 611
 612           Say N if unsure.
 613
 614 config CGROUP_FREEZER
 615         bool "Freezer cgroup subsystem"
 616         help
 617           Provides a way to freeze and unfreeze all tasks in a
 618           cgroup.
 619
 620 config CGROUP_DEVICE
 621         bool "Device controller for cgroups"
 622         help
 623           Provides a cgroup implementing whitelists for devices which
 624           a process in the cgroup can mknod or open.
 625
 626 config CPUSETS
 627         bool "Cpuset support"
 628         help
 629           This option will let you create and manage CPUSETs which
 630           allow dynamically partitioning a system into sets of CPUs and
 631           Memory Nodes and assigning tasks to run only within those sets.
 632           This is primarily useful on large SMP or NUMA systems.
 633
 634           Say N if unsure.
 635
 636 config PROC_PID_CPUSET
 637         bool "Include legacy /proc/<pid>/cpuset file"
 638         depends on CPUSETS
 639         default y
 640
 641 config CGROUP_CPUACCT
 642         bool "Simple CPU accounting cgroup subsystem"
 643         help
 644           Provides a simple Resource Controller for monitoring the
 645           total CPU consumed by the tasks in a cgroup.
 646
 647 config RESOURCE_COUNTERS
 648         bool "Resource counters"
 649         help
 650           This option enables controller independent resource accounting
 651           infrastructure that works with cgroups.
 652
 653 config CGROUP_MEM_RES_CTLR
 654         bool "Memory Resource Controller for Control Groups"
 655         depends on RESOURCE_COUNTERS
 656         select MM_OWNER
 657         help
 658           Provides a memory resource controller that manages both anonymous
 659           memory and page cache. (See Documentation/cgroups/memory.txt)
 660
 661           Note that setting this option increases fixed memory overhead
 662           associated with each page of memory in the system. By this,
 663           20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 664           usage tracking struct at boot. Total amount of this is printed out
 665           at boot.
 666
 667           Only enable when you're ok with these trade offs and really
 668           sure you need the memory resource controller. Even when you enable
 669           this, you can set "cgroup_disable=memory" at your boot option to
 670           disable memory resource controller and you can avoid overheads.
 671           (and lose benefits of memory resource controller)
 672
 673           This config option also selects MM_OWNER config option, which
 674           could in turn add some fork/exit overhead.
 675
 676 config CGROUP_MEM_RES_CTLR_SWAP
 677         bool "Memory Resource Controller Swap Extension"
 678         depends on CGROUP_MEM_RES_CTLR && SWAP
 679         help
 680           Add swap management feature to memory resource controller. When you
 681           enable this, you can limit mem+swap usage per cgroup. In other words,
 682           when you disable this, memory resource controller has no cares to
 683           usage of swap...a process can exhaust all of the swap. This extension
 684           is useful when you want to avoid exhaustion swap but this itself
 685           adds more overheads and consumes memory for remembering information.
 686           Especially if you use 32bit system or small memory system, please
 687           be careful about enabling this. When memory resource controller
 688           is disabled by boot option, this will be automatically disabled and
 689           there will be no overhead from this. Even when you set this config=y,
 690           if boot option "swapaccount=0" is set, swap will not be accounted.
 691           Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 692           size is 4096bytes, 512k per 1Gbytes of swap.
 693 config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
 694         bool "Memory Resource Controller Swap Extension enabled by default"
 695         depends on CGROUP_MEM_RES_CTLR_SWAP
 696         default y
 697         help
 698           Memory Resource Controller Swap Extension comes with its price in
 699           a bigger memory consumption. General purpose distribution kernels
 700           which want to enable the feature but keep it disabled by default
 701           and let the user enable it by swapaccount boot command line
 702           parameter should have this option unselected.
 703           For those who want to have the feature enabled by default should
 704           select this option (if, for some reason, they need to disable it
 705           then swapaccount=0 does the trick).
 706 config CGROUP_MEM_RES_CTLR_KMEM
 707         bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 708         depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
 709         default n
 710         help
 711           The Kernel Memory extension for Memory Resource Controller can limit
 712           the amount of memory used by kernel objects in the system. Those are
 713           fundamentally different from the entities handled by the standard
 714           Memory Controller, which are page-based, and can be swapped. Users of
 715           the kmem extension can use it to guarantee that no group of processes
 716           will ever exhaust kernel resources alone.
 717
 718 config CGROUP_PERF
 719         bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 720         depends on PERF_EVENTS && CGROUPS
 721         help
 722           This option extends the per-cpu mode to restrict monitoring to
 723           threads which belong to the cgroup specified and run on the
 724           designated cpu.
 725
 726           Say N if unsure.
 727
 728 menuconfig CGROUP_SCHED
 729         bool "Group CPU scheduler"
 730         default n
 731         help
 732           This feature lets CPU scheduler recognize task groups and control CPU
 733           bandwidth allocation to such task groups. It uses cgroups to group
 734           tasks.
 735
 736 if CGROUP_SCHED
 737 config FAIR_GROUP_SCHED
 738         bool "Group scheduling for SCHED_OTHER"
 739         depends on CGROUP_SCHED
 740         default CGROUP_SCHED
 741
 742 config CFS_BANDWIDTH
 743         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 744         depends on EXPERIMENTAL
 745         depends on FAIR_GROUP_SCHED
 746         default n
 747         help
 748           This option allows users to define CPU bandwidth rates (limits) for
 749           tasks running within the fair group scheduler.  Groups with no limit
 750           set are considered to be unconstrained and will run with no
 751           restriction.
 752           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 753
 754 config RT_GROUP_SCHED
 755         bool "Group scheduling for SCHED_RR/FIFO"
 756         depends on EXPERIMENTAL
 757         depends on CGROUP_SCHED
 758         default n
 759         help
 760           This feature lets you explicitly allocate real CPU bandwidth
 761           to task groups. If enabled, it will also make it impossible to
 762           schedule realtime tasks for non-root users until you allocate
 763           realtime bandwidth for them.
 764           See Documentation/scheduler/sched-rt-group.txt for more information.
 765
 766 endif #CGROUP_SCHED
 767
 768 config BLK_CGROUP
 769         tristate "Block IO controller"
 770         depends on BLOCK
 771         default n
 772         ---help---
 773         Generic block IO controller cgroup interface. This is the common
 774         cgroup interface which should be used by various IO controlling
 775         policies.
 776
 777         Currently, CFQ IO scheduler uses it to recognize task groups and
 778         control disk bandwidth allocation (proportional time slice allocation)
 779         to such task groups. It is also used by bio throttling logic in
 780         block layer to implement upper limit in IO rates on a device.
 781
 782         This option only enables generic Block IO controller infrastructure.
 783         One needs to also enable actual IO controlling logic/policy. For
 784         enabling proportional weight division of disk bandwidth in CFQ, set
 785         CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 786         CONFIG_BLK_DEV_THROTTLING=y.
 787
 788         See Documentation/cgroups/blkio-controller.txt for more information.
 789
 790 config DEBUG_BLK_CGROUP
 791         bool "Enable Block IO controller debugging"
 792         depends on BLK_CGROUP
 793         default n
 794         ---help---
 795         Enable some debugging help. Currently it exports additional stat
 796         files in a cgroup which can be useful for debugging.
 797
 798 endif # CGROUPS
 799
 800 config CHECKPOINT_RESTORE
 801         bool "Checkpoint/restore support" if EXPERT
 802         default n
 803         help
 804           Enables additional kernel features in a sake of checkpoint/restore.
 805           In particular it adds auxiliary prctl codes to setup process text,
 806           data and heap segment sizes, and a few additional /proc filesystem
 807           entries.
 808
 809           If unsure, say N here.
 810
 811 menuconfig NAMESPACES
 812         bool "Namespaces support" if EXPERT
 813         default !EXPERT
 814         help
 815           Provides the way to make tasks work with different objects using
 816           the same id. For example same IPC id may refer to different objects
 817           or same user id or pid may refer to different tasks when used in
 818           different namespaces.
 819
 820 if NAMESPACES
 821
 822 config UTS_NS
 823         bool "UTS namespace"
 824         default y
 825         help
 826           In this namespace tasks see different info provided with the
 827           uname() system call
 828
 829 config IPC_NS
 830         bool "IPC namespace"
 831         depends on (SYSVIPC || POSIX_MQUEUE)
 832         default y
 833         help
 834           In this namespace tasks work with IPC ids which correspond to
 835           different IPC objects in different namespaces.
 836
 837 config USER_NS
 838         bool "User namespace (EXPERIMENTAL)"
 839         depends on EXPERIMENTAL
 840         default y
 841         help
 842           This allows containers, i.e. vservers, to use user namespaces
 843           to provide different user info for different servers.
 844           If unsure, say N.
 845
 846 config PID_NS
 847         bool "PID Namespaces"
 848         default y
 849         help
 850           Support process id namespaces.  This allows having multiple
 851           processes with the same pid as long as they are in different
 852           pid namespaces.  This is a building block of containers.
 853
 854 config NET_NS
 855         bool "Network namespace"
 856         depends on NET
 857         default y
 858         help
 859           Allow user space to create what appear to be multiple instances
 860           of the network stack.
 861
 862 endif # NAMESPACES
 863
 864 config SCHED_AUTOGROUP
 865         bool "Automatic process group scheduling"
 866         select EVENTFD
 867         select CGROUPS
 868         select CGROUP_SCHED
 869         select FAIR_GROUP_SCHED
 870         help
 871           This option optimizes the scheduler for common desktop workloads by
 872           automatically creating and populating task groups.  This separation
 873           of workloads isolates aggressive CPU burners (like build jobs) from
 874           desktop applications.  Task group autogeneration is currently based
 875           upon task session.
 876
 877 config MM_OWNER
 878         bool
 879
 880 config SYSFS_DEPRECATED
 881         bool "Enable deprecated sysfs features to support old userspace tools"
 882         depends on SYSFS
 883         default n
 884         help
 885           This option adds code that switches the layout of the "block" class
 886           devices, to not show up in /sys/class/block/, but only in
 887           /sys/block/.
 888
 889           This switch is only active when the sysfs.deprecated=1 boot option is
 890           passed or the SYSFS_DEPRECATED_V2 option is set.
 891
 892           This option allows new kernels to run on old distributions and tools,
 893           which might get confused by /sys/class/block/. Since 2007/2008 all
 894           major distributions and tools handle this just fine.
 895
 896           Recent distributions and userspace tools after 2009/2010 depend on
 897           the existence of /sys/class/block/, and will not work with this
 898           option enabled.
 899
 900           Only if you are using a new kernel on an old distribution, you might
 901           need to say Y here.
 902
 903 config SYSFS_DEPRECATED_V2
 904         bool "Enable deprecated sysfs features by default"
 905         default n
 906         depends on SYSFS
 907         depends on SYSFS_DEPRECATED
 908         help
 909           Enable deprecated sysfs by default.
 910
 911           See the CONFIG_SYSFS_DEPRECATED option for more details about this
 912           option.
 913
 914           Only if you are using a new kernel on an old distribution, you might
 915           need to say Y here. Even then, odds are you would not need it
 916           enabled, you can always pass the boot option if absolutely necessary.
 917
 918 config RELAY
 919         bool "Kernel->user space relay support (formerly relayfs)"
 920         help
 921           This option enables support for relay interface support in
 922           certain file systems (such as debugfs).
 923           It is designed to provide an efficient mechanism for tools and
 924           facilities to relay large amounts of data from kernel space to
 925           user space.
 926
 927           If unsure, say N.
 928
 929 config BLK_DEV_INITRD
 930         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 931         depends on BROKEN || !FRV
 932         help
 933           The initial RAM filesystem is a ramfs which is loaded by the
 934           boot loader (loadlin or lilo) and that is mounted as root
 935           before the normal boot procedure. It is typically used to
 936           load modules needed to mount the "real" root file system,
 937           etc. See <file:Documentation/initrd.txt> for details.
 938
 939           If RAM disk support (BLK_DEV_RAM) is also included, this
 940           also enables initial RAM disk (initrd) support and adds
 941           15 Kbytes (more on some other architectures) to the kernel size.
 942
 943           If unsure say Y.
 944
 945 if BLK_DEV_INITRD
 946
 947 source "usr/Kconfig"
 948
 949 endif
 950
 951 config CC_OPTIMIZE_FOR_SIZE
 952         bool "Optimize for size"
 953         help
 954           Enabling this option will pass "-Os" instead of "-O2" to gcc
 955           resulting in a smaller kernel.
 956
 957           If unsure, say Y.
 958
 959 config SYSCTL
 960         bool
 961
 962 config ANON_INODES
 963         bool
 964
 965 menuconfig EXPERT
 966         bool "Configure standard kernel features (expert users)"
 967         # Unhide debug options, to make the on-by-default options visible
 968         select DEBUG_KERNEL
 969         help
 970           This option allows certain base kernel options and settings
 971           to be disabled or tweaked. This is for specialized
 972           environments which can tolerate a "non-standard" kernel.
 973           Only use this if you really know what you are doing.
 974
 975 config UID16
 976         bool "Enable 16-bit UID system calls" if EXPERT
 977         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 978         default y
 979         help
 980           This enables the legacy 16-bit UID syscall wrappers.
 981
 982 config SYSCTL_SYSCALL
 983         bool "Sysctl syscall support" if EXPERT
 984         depends on PROC_SYSCTL
 985         default n
 986         select SYSCTL
 987         ---help---
 988           sys_sysctl uses binary paths that have been found challenging
 989           to properly maintain and use.  The interface in /proc/sys
 990           using paths with ascii names is now the primary path to this
 991           information.
 992
 993           Almost nothing using the binary sysctl interface so if you are
 994           trying to save some space it is probably safe to disable this,
 995           making your kernel marginally smaller.
 996
 997           If unsure say N here.
 998
 999 config KALLSYMS
1000          bool "Load all symbols for debugging/ksymoops" if EXPERT
1001          default y
1002          help
1003            Say Y here to let the kernel print out symbolic crash information and
1004            symbolic stack backtraces. This increases the size of the kernel
1005            somewhat, as all symbols have to be loaded into the kernel image.
1006
1007 config KALLSYMS_ALL
1008         bool "Include all symbols in kallsyms"
1009         depends on DEBUG_KERNEL && KALLSYMS
1010         help
1011            Normally kallsyms only contains the symbols of functions for nicer
1012            OOPS messages and backtraces (i.e., symbols from the text and inittext
1013            sections). This is sufficient for most cases. And only in very rare
1014            cases (e.g., when a debugger is used) all symbols are required (e.g.,
1015            names of variables from the data sections, etc).
1016
1017            This option makes sure that all symbols are loaded into the kernel
1018            image (i.e., symbols from all sections) in cost of increased kernel
1019            size (depending on the kernel configuration, it may be 300KiB or
1020            something like this).
1021
1022            Say N unless you really need all symbols.
1023
1024 config HOTPLUG
1025         bool "Support for hot-pluggable devices" if EXPERT
1026         default y
1027         help
1028           This option is provided for the case where no hotplug or uevent
1029           capabilities is wanted by the kernel.  You should only consider
1030           disabling this option for embedded systems that do not use modules, a
1031           dynamic /dev tree, or dynamic device discovery.  Just say Y.
1032
1033 config PRINTK
1034         default y
1035         bool "Enable support for printk" if EXPERT
1036         help
1037           This option enables normal printk support. Removing it
1038           eliminates most of the message strings from the kernel image
1039           and makes the kernel more or less silent. As this makes it
1040           very difficult to diagnose system problems, saying N here is
1041           strongly discouraged.
1042
1043 config BUG
1044         bool "BUG() support" if EXPERT
1045         default y
1046         help
1047           Disabling this option eliminates support for BUG and WARN, reducing
1048           the size of your kernel image and potentially quietly ignoring
1049           numerous fatal conditions. You should only consider disabling this
1050           option for embedded systems with no facilities for reporting errors.
1051           Just say Y.
1052
1053 config ELF_CORE
1054         default y
1055         bool "Enable ELF core dumps" if EXPERT
1056         help
1057           Enable support for generating core dumps. Disabling saves about 4k.
1058
1059
1060 config PCSPKR_PLATFORM
1061         bool "Enable PC-Speaker support" if EXPERT
1062         depends on HAVE_PCSPKR_PLATFORM
1063         select I8253_LOCK
1064         default y
1065         help
1066           This option allows to disable the internal PC-Speaker
1067           support, saving some memory.
1068
1069 config HAVE_PCSPKR_PLATFORM
1070         bool
1071
1072 config BASE_FULL
1073         default y
1074         bool "Enable full-sized data structures for core" if EXPERT
1075         help
1076           Disabling this option reduces the size of miscellaneous core
1077           kernel data structures. This saves memory on small machines,
1078           but may reduce performance.
1079
1080 config FUTEX
1081         bool "Enable futex support" if EXPERT
1082         default y
1083         select RT_MUTEXES
1084         help
1085           Disabling this option will cause the kernel to be built without
1086           support for "fast userspace mutexes".  The resulting kernel may not
1087           run glibc-based applications correctly.
1088
1089 config EPOLL
1090         bool "Enable eventpoll support" if EXPERT
1091         default y
1092         select ANON_INODES
1093         help
1094           Disabling this option will cause the kernel to be built without
1095           support for epoll family of system calls.
1096
1097 config SIGNALFD
1098         bool "Enable signalfd() system call" if EXPERT
1099         select ANON_INODES
1100         default y
1101         help
1102           Enable the signalfd() system call that allows to receive signals
1103           on a file descriptor.
1104
1105           If unsure, say Y.
1106
1107 config TIMERFD
1108         bool "Enable timerfd() system call" if EXPERT
1109         select ANON_INODES
1110         default y
1111         help
1112           Enable the timerfd() system call that allows to receive timer
1113           events on a file descriptor.
1114
1115           If unsure, say Y.
1116
1117 config EVENTFD
1118         bool "Enable eventfd() system call" if EXPERT
1119         select ANON_INODES
1120         default y
1121         help
1122           Enable the eventfd() system call that allows to receive both
1123           kernel notification (ie. KAIO) or userspace notifications.
1124
1125           If unsure, say Y.
1126
1127 config SHMEM
1128         bool "Use full shmem filesystem" if EXPERT
1129         default y
1130         depends on MMU
1131         help
1132           The shmem is an internal filesystem used to manage shared memory.
1133           It is backed by swap and manages resource limits. It is also exported
1134           to userspace as tmpfs if TMPFS is enabled. Disabling this
1135           option replaces shmem and tmpfs with the much simpler ramfs code,
1136           which may be appropriate on small systems without swap.
1137
1138 config AIO
1139         bool "Enable AIO support" if EXPERT
1140         default y
1141         help
1142           This option enables POSIX asynchronous I/O which may by used
1143           by some high performance threaded applications. Disabling
1144           this option saves about 7k.
1145
1146 config EMBEDDED
1147         bool "Embedded system"
1148         select EXPERT
1149         help
1150           This option should be enabled if compiling the kernel for
1151           an embedded system so certain expert options are available
1152           for configuration.
1153
1154 config HAVE_PERF_EVENTS
1155         bool
1156         help
1157           See tools/perf/design.txt for details.
1158
1159 config PERF_USE_VMALLOC
1160         bool
1161         help
1162           See tools/perf/design.txt for details
1163
1164 menu "Kernel Performance Events And Counters"
1165
1166 config PERF_EVENTS
1167         bool "Kernel performance events and counters"
1168         default y if (PROFILING || PERF_COUNTERS)
1169         depends on HAVE_PERF_EVENTS
1170         select ANON_INODES
1171         select IRQ_WORK
1172         help
1173           Enable kernel support for various performance events provided
1174           by software and hardware.
1175
1176           Software events are supported either built-in or via the
1177           use of generic tracepoints.
1178
1179           Most modern CPUs support performance events via performance
1180           counter registers. These registers count the number of certain
1181           types of hw events: such as instructions executed, cachemisses
1182           suffered, or branches mis-predicted - without slowing down the
1183           kernel or applications. These registers can also trigger interrupts
1184           when a threshold number of events have passed - and can thus be
1185           used to profile the code that runs on that CPU.
1186
1187           The Linux Performance Event subsystem provides an abstraction of
1188           these software and hardware event capabilities, available via a
1189           system call and used by the "perf" utility in tools/perf/. It
1190           provides per task and per CPU counters, and it provides event
1191           capabilities on top of those.
1192
1193           Say Y if unsure.
1194
1195 config PERF_COUNTERS
1196         bool "Kernel performance counters (old config option)"
1197         depends on HAVE_PERF_EVENTS
1198         help
1199           This config has been obsoleted by the PERF_EVENTS
1200           config option - please see that one for details.
1201
1202           It has no effect on the kernel whether you enable
1203           it or not, it is a compatibility placeholder.
1204
1205           Say N if unsure.
1206
1207 config DEBUG_PERF_USE_VMALLOC
1208         default n
1209         bool "Debug: use vmalloc to back perf mmap() buffers"
1210         depends on PERF_EVENTS && DEBUG_KERNEL
1211         select PERF_USE_VMALLOC
1212         help
1213          Use vmalloc memory to back perf mmap() buffers.
1214
1215          Mostly useful for debugging the vmalloc code on platforms
1216          that don't require it.
1217
1218          Say N if unsure.
1219
1220 endmenu
1221
1222 config VM_EVENT_COUNTERS
1223         default y
1224         bool "Enable VM event counters for /proc/vmstat" if EXPERT
1225         help
1226           VM event counters are needed for event counts to be shown.
1227           This option allows the disabling of the VM event counters
1228           on EXPERT systems.  /proc/vmstat will only show page counts
1229           if VM event counters are disabled.
1230
1231 config PCI_QUIRKS
1232         default y
1233         bool "Enable PCI quirk workarounds" if EXPERT
1234         depends on PCI
1235         help
1236           This enables workarounds for various PCI chipset
1237           bugs/quirks. Disable this only if your target machine is
1238           unaffected by PCI quirks.
1239
1240 config SLUB_DEBUG
1241         default y
1242         bool "Enable SLUB debugging support" if EXPERT
1243         depends on SLUB && SYSFS
1244         help
1245           SLUB has extensive debug support features. Disabling these can
1246           result in significant savings in code size. This also disables
1247           SLUB sysfs support. /sys/slab will not exist and there will be
1248           no support for cache validation etc.
1249
1250 config COMPAT_BRK
1251         bool "Disable heap randomization"
1252         default y
1253         help
1254           Randomizing heap placement makes heap exploits harder, but it
1255           also breaks ancient binaries (including anything libc5 based).
1256           This option changes the bootup default to heap randomization
1257           disabled, and can be overridden at runtime by setting
1258           /proc/sys/kernel/randomize_va_space to 2.
1259
1260           On non-ancient distros (post-2000 ones) N is usually a safe choice.
1261
1262 choice
1263         prompt "Choose SLAB allocator"
1264         default SLUB
1265         help
1266            This option allows to select a slab allocator.
1267
1268 config SLAB
1269         bool "SLAB"
1270         help
1271           The regular slab allocator that is established and known to work
1272           well in all environments. It organizes cache hot objects in
1273           per cpu and per node queues.
1274
1275 config SLUB
1276         bool "SLUB (Unqueued Allocator)"
1277         help
1278            SLUB is a slab allocator that minimizes cache line usage
1279            instead of managing queues of cached objects (SLAB approach).
1280            Per cpu caching is realized using slabs of objects instead
1281            of queues of objects. SLUB can use memory efficiently
1282            and has enhanced diagnostics. SLUB is the default choice for
1283            a slab allocator.
1284
1285 config SLOB
1286         depends on EXPERT
1287         bool "SLOB (Simple Allocator)"
1288         help
1289            SLOB replaces the stock allocator with a drastically simpler
1290            allocator. SLOB is generally more space efficient but
1291            does not perform as well on large systems.
1292
1293 endchoice
1294
1295 config MMAP_ALLOW_UNINITIALIZED
1296         bool "Allow mmapped anonymous memory to be uninitialized"
1297         depends on EXPERT && !MMU
1298         default n
1299         help
1300           Normally, and according to the Linux spec, anonymous memory obtained
1301           from mmap() has it's contents cleared before it is passed to
1302           userspace.  Enabling this config option allows you to request that
1303           mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1304           providing a huge performance boost.  If this option is not enabled,
1305           then the flag will be ignored.
1306
1307           This is taken advantage of by uClibc's malloc(), and also by
1308           ELF-FDPIC binfmt's brk and stack allocator.
1309
1310           Because of the obvious security issues, this option should only be
1311           enabled on embedded devices where you control what is run in
1312           userspace.  Since that isn't generally a problem on no-MMU systems,
1313           it is normally safe to say Y here.
1314
1315           See Documentation/nommu-mmap.txt for more information.
1316
1317 config PROFILING
1318         bool "Profiling support"
1319         help
1320           Say Y here to enable the extended profiling support mechanisms used
1321           by profilers such as OProfile.
1322
1323 #
1324 # Place an empty function call at each tracepoint site. Can be
1325 # dynamically changed for a probe function.
1326 #
1327 config TRACEPOINTS
1328         bool
1329
1330 source "arch/Kconfig"
1331
1332 endmenu         # General setup
1333
1334 config HAVE_GENERIC_DMA_COHERENT
1335         bool
1336         default n
1337
1338 config SLABINFO
1339         bool
1340         depends on PROC_FS
1341         depends on SLAB || SLUB_DEBUG
1342         default y
1343
1344 config RT_MUTEXES
1345         boolean
1346
1347 config BASE_SMALL
1348         int
1349         default 0 if BASE_FULL
1350         default 1 if !BASE_FULL
1351
1352 menuconfig MODULES
1353         bool "Enable loadable module support"
1354         help
1355           Kernel modules are small pieces of compiled code which can
1356           be inserted in the running kernel, rather than being
1357           permanently built into the kernel.  You use the "modprobe"
1358           tool to add (and sometimes remove) them.  If you say Y here,
1359           many parts of the kernel can be built as modules (by
1360           answering M instead of Y where indicated): this is most
1361           useful for infrequently used options which are not required
1362           for booting.  For more information, see the man pages for
1363           modprobe, lsmod, modinfo, insmod and rmmod.
1364
1365           If you say Y here, you will need to run "make
1366           modules_install" to put the modules under /lib/modules/
1367           where modprobe can find them (you may need to be root to do
1368           this).
1369
1370           If unsure, say Y.
1371
1372 if MODULES
1373
1374 config MODULE_FORCE_LOAD
1375         bool "Forced module loading"
1376         default n
1377         help
1378           Allow loading of modules without version information (ie. modprobe
1379           --force).  Forced module loading sets the 'F' (forced) taint flag and
1380           is usually a really bad idea.
1381
1382 config MODULE_UNLOAD
1383         bool "Module unloading"
1384         help
1385           Without this option you will not be able to unload any
1386           modules (note that some modules may not be unloadable
1387           anyway), which makes your kernel smaller, faster
1388           and simpler.  If unsure, say Y.
1389
1390 config MODULE_FORCE_UNLOAD
1391         bool "Forced module unloading"
1392         depends on MODULE_UNLOAD && EXPERIMENTAL
1393         help
1394           This option allows you to force a module to unload, even if the
1395           kernel believes it is unsafe: the kernel will remove the module
1396           without waiting for anyone to stop using it (using the -f option to
1397           rmmod).  This is mainly for kernel developers and desperate users.
1398           If unsure, say N.
1399
1400 config MODVERSIONS
1401         bool "Module versioning support"
1402         help
1403           Usually, you have to use modules compiled with your kernel.
1404           Saying Y here makes it sometimes possible to use modules
1405           compiled for different kernels, by adding enough information
1406           to the modules to (hopefully) spot any changes which would
1407           make them incompatible with the kernel you are running.  If
1408           unsure, say N.
1409
1410 config MODULE_SRCVERSION_ALL
1411         bool "Source checksum for all modules"
1412         help
1413           Modules which contain a MODULE_VERSION get an extra "srcversion"
1414           field inserted into their modinfo section, which contains a
1415           sum of the source files which made it.  This helps maintainers
1416           see exactly which source was used to build a module (since
1417           others sometimes change the module source without updating
1418           the version).  With this option, such a "srcversion" field
1419           will be created for all modules.  If unsure, say N.
1420
1421 endif # MODULES
1422
1423 config INIT_ALL_POSSIBLE
1424         bool
1425         help
1426           Back when each arch used to define their own cpu_online_map and
1427           cpu_possible_map, some of them chose to initialize cpu_possible_map
1428           with all 1s, and others with all 0s.  When they were centralised,
1429           it was better to provide this option than to break all the archs
1430           and have several arch maintainers pursuing me down dark alleys.
1431
1432 config STOP_MACHINE
1433         bool
1434         default y
1435         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1436         help
1437           Need stop_machine() primitive.
1438
1439 source "block/Kconfig"
1440
1441 config PREEMPT_NOTIFIERS
1442         bool
1443
1444 config PADATA
1445         depends on SMP
1446         bool
1447
1448 source "kernel/Kconfig.locks"