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  54           drivers that have been replaced by something else, and/or are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