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  53           drivers that have been replaced by something else, and/or are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_FANOUT
 442         int "Tree-based hierarchical RCU fanout value"
 443         range 2 64 if 64BIT
 444         range 2 32 if !64BIT
 445         depends on TREE_RCU || TREE_PREEMPT_RCU
 446         default 64 if 64BIT
 447         default 32 if !64BIT
 448         help
 449           This option controls the fanout of hierarchical implementations
 450           of RCU, allowing RCU to work efficiently on machines with
 451           large numbers of CPUs.  This value must be at least the fourth
 452           root of NR_CPUS, which allows NR_CPUS to be insanely large.
 453           The default value of RCU_FANOUT should be used for production
 454           systems, but if you are stress-testing the RCU implementation
 455           itself, small RCU_FANOUT values allow you to test large-system
 456           code paths on small(er) systems.
 457
 458           Select a specific number if testing RCU itself.
 459           Take the default if unsure.
 460
 461 config RCU_FANOUT_EXACT
 462         bool "Disable tree-based hierarchical RCU auto-balancing"
 463         depends on TREE_RCU || TREE_PREEMPT_RCU
 464         default n
 465         help
 466           This option forces use of the exact RCU_FANOUT value specified,
 467           regardless of imbalances in the hierarchy.  This is useful for
 468           testing RCU itself, and might one day be useful on systems with
 469           strong NUMA behavior.
 470
 471           Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 472
 473           Say N if unsure.
 474
 475 config RCU_FAST_NO_HZ
 476         bool "Accelerate last non-dyntick-idle CPU's grace periods"
 477         depends on NO_HZ && SMP
 478         default n
 479         help
 480           This option causes RCU to attempt to accelerate grace periods
 481           in order to allow CPUs to enter dynticks-idle state more
 482           quickly.  On the other hand, this option increases the overhead
 483           of the dynticks-idle checking, particularly on systems with
 484           large numbers of CPUs.
 485
 486           Say Y if energy efficiency is critically important, particularly
 487                 if you have relatively few CPUs.
 488
 489           Say N if you are unsure.
 490
 491 config TREE_RCU_TRACE
 492         def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 493         select DEBUG_FS
 494         help
 495           This option provides tracing for the TREE_RCU and
 496           TREE_PREEMPT_RCU implementations, permitting Makefile to
 497           trivially select kernel/rcutree_trace.c.
 498
 499 config RCU_BOOST
 500         bool "Enable RCU priority boosting"
 501         depends on RT_MUTEXES && PREEMPT_RCU
 502         default n
 503         help
 504           This option boosts the priority of preempted RCU readers that
 505           block the current preemptible RCU grace period for too long.
 506           This option also prevents heavy loads from blocking RCU
 507           callback invocation for all flavors of RCU.
 508
 509           Say Y here if you are working with real-time apps or heavy loads
 510           Say N here if you are unsure.
 511
 512 config RCU_BOOST_PRIO
 513         int "Real-time priority to boost RCU readers to"
 514         range 1 99
 515         depends on RCU_BOOST
 516         default 1
 517         help
 518           This option specifies the real-time priority to which preempted
 519           RCU readers are to be boosted.  If you are working with CPU-bound
 520           real-time applications, you should specify a priority higher then
 521           the highest-priority CPU-bound application.
 522
 523           Specify the real-time priority, or take the default if unsure.
 524
 525 config RCU_BOOST_DELAY
 526         int "Milliseconds to delay boosting after RCU grace-period start"
 527         range 0 3000
 528         depends on RCU_BOOST
 529         default 500
 530         help
 531           This option specifies the time to wait after the beginning of
 532           a given grace period before priority-boosting preempted RCU
 533           readers blocking that grace period.  Note that any RCU reader
 534           blocking an expedited RCU grace period is boosted immediately.
 535
 536           Accept the default if unsure.
 537
 538 endmenu # "RCU Subsystem"
 539
 540 config IKCONFIG
 541         tristate "Kernel .config support"
 542         ---help---
 543           This option enables the complete Linux kernel ".config" file
 544           contents to be saved in the kernel. It provides documentation
 545           of which kernel options are used in a running kernel or in an
 546           on-disk kernel.  This information can be extracted from the kernel
 547           image file with the script scripts/extract-ikconfig and used as
 548           input to rebuild the current kernel or to build another kernel.
 549           It can also be extracted from a running kernel by reading
 550           /proc/config.gz if enabled (below).
 551
 552 config IKCONFIG_PROC
 553         bool "Enable access to .config through /proc/config.gz"
 554         depends on IKCONFIG && PROC_FS
 555         ---help---
 556           This option enables access to the kernel configuration file
 557           through /proc/config.gz.
 558
 559 config LOG_BUF_SHIFT
 560         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 561         range 12 21
 562         default 17
 563         help
 564           Select kernel log buffer size as a power of 2.
 565           Examples:
 566                      17 => 128 KB
 567                      16 => 64 KB
 568                      15 => 32 KB
 569                      14 => 16 KB
 570                      13 =>  8 KB
 571                      12 =>  4 KB
 572
 573 #
 574 # Architectures with an unreliable sched_clock() should select this:
 575 #
 576 config HAVE_UNSTABLE_SCHED_CLOCK
 577         bool
 578
 579 menuconfig CGROUPS
 580         boolean "Control Group support"
 581         depends on EVENTFD
 582         help
 583           This option adds support for grouping sets of processes together, for
 584           use with process control subsystems such as Cpusets, CFS, memory
 585           controls or device isolation.
 586           See
 587                 - Documentation/scheduler/sched-design-CFS.txt  (CFS)
 588                 - Documentation/cgroups/ (features for grouping, isolation
 589                                           and resource control)
 590
 591           Say N if unsure.
 592
 593 if CGROUPS
 594
 595 config CGROUP_DEBUG
 596         bool "Example debug cgroup subsystem"
 597         default n
 598         help
 599           This option enables a simple cgroup subsystem that
 600           exports useful debugging information about the cgroups
 601           framework.
 602
 603           Say N if unsure.
 604
 605 config CGROUP_FREEZER
 606         bool "Freezer cgroup subsystem"
 607         help
 608           Provides a way to freeze and unfreeze all tasks in a
 609           cgroup.
 610
 611 config CGROUP_DEVICE
 612         bool "Device controller for cgroups"
 613         help
 614           Provides a cgroup implementing whitelists for devices which
 615           a process in the cgroup can mknod or open.
 616
 617 config CPUSETS
 618         bool "Cpuset support"
 619         help
 620           This option will let you create and manage CPUSETs which
 621           allow dynamically partitioning a system into sets of CPUs and
 622           Memory Nodes and assigning tasks to run only within those sets.
 623           This is primarily useful on large SMP or NUMA systems.
 624
 625           Say N if unsure.
 626
 627 config PROC_PID_CPUSET
 628         bool "Include legacy /proc/<pid>/cpuset file"
 629         depends on CPUSETS
 630         default y
 631
 632 config CGROUP_CPUACCT
 633         bool "Simple CPU accounting cgroup subsystem"
 634         help
 635           Provides a simple Resource Controller for monitoring the
 636           total CPU consumed by the tasks in a cgroup.
 637
 638 config RESOURCE_COUNTERS
 639         bool "Resource counters"
 640         help
 641           This option enables controller independent resource accounting
 642           infrastructure that works with cgroups.
 643
 644 config CGROUP_MEM_RES_CTLR
 645         bool "Memory Resource Controller for Control Groups"
 646         depends on RESOURCE_COUNTERS
 647         select MM_OWNER
 648         help
 649           Provides a memory resource controller that manages both anonymous
 650           memory and page cache. (See Documentation/cgroups/memory.txt)
 651
 652           Note that setting this option increases fixed memory overhead
 653           associated with each page of memory in the system. By this,
 654           20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 655           usage tracking struct at boot. Total amount of this is printed out
 656           at boot.
 657
 658           Only enable when you're ok with these trade offs and really
 659           sure you need the memory resource controller. Even when you enable
 660           this, you can set "cgroup_disable=memory" at your boot option to
 661           disable memory resource controller and you can avoid overheads.
 662           (and lose benefits of memory resource controller)
 663
 664           This config option also selects MM_OWNER config option, which
 665           could in turn add some fork/exit overhead.
 666
 667 config CGROUP_MEM_RES_CTLR_SWAP
 668         bool "Memory Resource Controller Swap Extension"
 669         depends on CGROUP_MEM_RES_CTLR && SWAP
 670         help
 671           Add swap management feature to memory resource controller. When you
 672           enable this, you can limit mem+swap usage per cgroup. In other words,
 673           when you disable this, memory resource controller has no cares to
 674           usage of swap...a process can exhaust all of the swap. This extension
 675           is useful when you want to avoid exhaustion swap but this itself
 676           adds more overheads and consumes memory for remembering information.
 677           Especially if you use 32bit system or small memory system, please
 678           be careful about enabling this. When memory resource controller
 679           is disabled by boot option, this will be automatically disabled and
 680           there will be no overhead from this. Even when you set this config=y,
 681           if boot option "swapaccount=0" is set, swap will not be accounted.
 682           Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 683           size is 4096bytes, 512k per 1Gbytes of swap.
 684 config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
 685         bool "Memory Resource Controller Swap Extension enabled by default"
 686         depends on CGROUP_MEM_RES_CTLR_SWAP
 687         default y
 688         help
 689           Memory Resource Controller Swap Extension comes with its price in
 690           a bigger memory consumption. General purpose distribution kernels
 691           which want to enable the feature but keep it disabled by default
 692           and let the user enable it by swapaccount boot command line
 693           parameter should have this option unselected.
 694           For those who want to have the feature enabled by default should
 695           select this option (if, for some reason, they need to disable it
 696           then swapaccount=0 does the trick).
 697 config CGROUP_MEM_RES_CTLR_KMEM
 698         bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 699         depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
 700         default n
 701         help
 702           The Kernel Memory extension for Memory Resource Controller can limit
 703           the amount of memory used by kernel objects in the system. Those are
 704           fundamentally different from the entities handled by the standard
 705           Memory Controller, which are page-based, and can be swapped. Users of
 706           the kmem extension can use it to guarantee that no group of processes
 707           will ever exhaust kernel resources alone.
 708
 709 config CGROUP_PERF
 710         bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 711         depends on PERF_EVENTS && CGROUPS
 712         help
 713           This option extends the per-cpu mode to restrict monitoring to
 714           threads which belong to the cgroup specified and run on the
 715           designated cpu.
 716
 717           Say N if unsure.
 718
 719 menuconfig CGROUP_SCHED
 720         bool "Group CPU scheduler"
 721         default n
 722         help
 723           This feature lets CPU scheduler recognize task groups and control CPU
 724           bandwidth allocation to such task groups. It uses cgroups to group
 725           tasks.
 726
 727 if CGROUP_SCHED
 728 config FAIR_GROUP_SCHED
 729         bool "Group scheduling for SCHED_OTHER"
 730         depends on CGROUP_SCHED
 731         default CGROUP_SCHED
 732
 733 config CFS_BANDWIDTH
 734         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 735         depends on EXPERIMENTAL
 736         depends on FAIR_GROUP_SCHED
 737         default n
 738         help
 739           This option allows users to define CPU bandwidth rates (limits) for
 740           tasks running within the fair group scheduler.  Groups with no limit
 741           set are considered to be unconstrained and will run with no
 742           restriction.
 743           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 744
 745 config RT_GROUP_SCHED
 746         bool "Group scheduling for SCHED_RR/FIFO"
 747         depends on EXPERIMENTAL
 748         depends on CGROUP_SCHED
 749         default n
 750         help
 751           This feature lets you explicitly allocate real CPU bandwidth
 752           to task groups. If enabled, it will also make it impossible to
 753           schedule realtime tasks for non-root users until you allocate
 754           realtime bandwidth for them.
 755           See Documentation/scheduler/sched-rt-group.txt for more information.
 756
 757 endif #CGROUP_SCHED
 758
 759 config BLK_CGROUP
 760         tristate "Block IO controller"
 761         depends on BLOCK
 762         default n
 763         ---help---
 764         Generic block IO controller cgroup interface. This is the common
 765         cgroup interface which should be used by various IO controlling
 766         policies.
 767
 768         Currently, CFQ IO scheduler uses it to recognize task groups and
 769         control disk bandwidth allocation (proportional time slice allocation)
 770         to such task groups. It is also used by bio throttling logic in
 771         block layer to implement upper limit in IO rates on a device.
 772
 773         This option only enables generic Block IO controller infrastructure.
 774         One needs to also enable actual IO controlling logic/policy. For
 775         enabling proportional weight division of disk bandwidth in CFQ, set
 776         CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 777         CONFIG_BLK_DEV_THROTTLING=y.
 778
 779         See Documentation/cgroups/blkio-controller.txt for more information.
 780
 781 config DEBUG_BLK_CGROUP
 782         bool "Enable Block IO controller debugging"
 783         depends on BLK_CGROUP
 784         default n
 785         ---help---
 786         Enable some debugging help. Currently it exports additional stat
 787         files in a cgroup which can be useful for debugging.
 788
 789 endif # CGROUPS
 790
 791 config CHECKPOINT_RESTORE
 792         bool "Checkpoint/restore support" if EXPERT
 793         default n
 794         help
 795           Enables additional kernel features in a sake of checkpoint/restore.
 796           In particular it adds auxiliary prctl codes to setup process text,
 797           data and heap segment sizes, and a few additional /proc filesystem
 798           entries.
 799
 800           If unsure, say N here.
 801
 802 menuconfig NAMESPACES
 803         bool "Namespaces support" if EXPERT
 804         default !EXPERT
 805         help
 806           Provides the way to make tasks work with different objects using
 807           the same id. For example same IPC id may refer to different objects
 808           or same user id or pid may refer to different tasks when used in
 809           different namespaces.
 810
 811 if NAMESPACES
 812
 813 config UTS_NS
 814         bool "UTS namespace"
 815         default y
 816         help
 817           In this namespace tasks see different info provided with the
 818           uname() system call
 819
 820 config IPC_NS
 821         bool "IPC namespace"
 822         depends on (SYSVIPC || POSIX_MQUEUE)
 823         default y
 824         help
 825           In this namespace tasks work with IPC ids which correspond to
 826           different IPC objects in different namespaces.
 827
 828 config USER_NS
 829         bool "User namespace (EXPERIMENTAL)"
 830         depends on EXPERIMENTAL
 831         depends on UIDGID_CONVERTED
 832         select UIDGID_STRICT_TYPE_CHECKS
 833
 834         default n
 835         help
 836           This allows containers, i.e. vservers, to use user namespaces
 837           to provide different user info for different servers.
 838           If unsure, say N.
 839
 840 config PID_NS
 841         bool "PID Namespaces"
 842         default y
 843         help
 844           Support process id namespaces.  This allows having multiple
 845           processes with the same pid as long as they are in different
 846           pid namespaces.  This is a building block of containers.
 847
 848 config NET_NS
 849         bool "Network namespace"
 850         depends on NET
 851         default y
 852         help
 853           Allow user space to create what appear to be multiple instances
 854           of the network stack.
 855
 856 endif # NAMESPACES
 857
 858 config UIDGID_CONVERTED
 859         # True if all of the selected software conmponents are known
 860         # to have uid_t and gid_t converted to kuid_t and kgid_t
 861         # where appropriate and are otherwise safe to use with
 862         # the user namespace.
 863         bool
 864         default y
 865
 866         # List of kernel pieces that need user namespace work
 867         # Features
 868         depends on CGROUPS = n
 869         depends on MIGRATION = n
 870         depends on NUMA = n
 871         depends on SYSVIPC = n
 872         depends on IMA = n
 873         depends on EVM = n
 874         depends on KEYS = n
 875         depends on AUDIT = n
 876         depends on AUDITSYSCALL = n
 877         depends on TASKSTATS = n
 878         depends on TRACING = n
 879         depends on FS_POSIX_ACL = n
 880         depends on QUOTA = n
 881         depends on QUOTACTL = n
 882         depends on DEBUG_CREDENTIALS = n
 883         depends on BSD_PROCESS_ACCT = n
 884         depends on DRM = n
 885         depends on PROC_EVENTS = n
 886
 887         # Networking
 888         depends on NET = n
 889         depends on NET_9P = n
 890         depends on IPX = n
 891         depends on PHONET = n
 892         depends on NET_CLS_FLOW = n
 893         depends on NETFILTER_XT_MATCH_OWNER = n
 894         depends on NETFILTER_XT_MATCH_RECENT = n
 895         depends on NETFILTER_XT_TARGET_LOG = n
 896         depends on NETFILTER_NETLINK_LOG = n
 897         depends on INET = n
 898         depends on IPV6 = n
 899         depends on IP_SCTP = n
 900         depends on AF_RXRPC = n
 901         depends on LLC2 = n
 902         depends on NET_KEY = n
 903         depends on INET_DIAG = n
 904         depends on DNS_RESOLVER = n
 905         depends on AX25 = n
 906         depends on ATALK = n
 907
 908         # Filesystems
 909         depends on USB_DEVICEFS = n
 910         depends on USB_GADGETFS = n
 911         depends on USB_FUNCTIONFS = n
 912         depends on DEVTMPFS = n
 913         depends on XENFS = n
 914
 915         depends on 9P_FS = n
 916         depends on ADFS_FS = n
 917         depends on AFFS_FS = n
 918         depends on AFS_FS = n
 919         depends on AUTOFS4_FS = n
 920         depends on BEFS_FS = n
 921         depends on BFS_FS = n
 922         depends on BTRFS_FS = n
 923         depends on CEPH_FS = n
 924         depends on CIFS = n
 925         depends on CODA_FS = n
 926         depends on CONFIGFS_FS = n
 927         depends on CRAMFS = n
 928         depends on DEBUG_FS = n
 929         depends on ECRYPT_FS = n
 930         depends on EFS_FS = n
 931         depends on EXOFS_FS = n
 932         depends on EXT4_FS = n
 933         depends on FAT_FS = n
 934         depends on FUSE_FS = n
 935         depends on GFS2_FS = n
 936         depends on HFS_FS = n
 937         depends on HFSPLUS_FS = n
 938         depends on HPFS_FS = n
 939         depends on HUGETLBFS = n
 940         depends on ISO9660_FS = n
 941         depends on JFFS2_FS = n
 942         depends on JFS_FS = n
 943         depends on LOGFS = n
 944         depends on MINIX_FS = n
 945         depends on NCP_FS = n
 946         depends on NFSD = n
 947         depends on NFS_FS = n
 948         depends on NILFS2_FS = n
 949         depends on NTFS_FS = n
 950         depends on OCFS2_FS = n
 951         depends on OMFS_FS = n
 952         depends on PROC_FS = n
 953         depends on PROC_SYSCTL = n
 954         depends on QNX4FS_FS = n
 955         depends on QNX6FS_FS = n
 956         depends on REISERFS_FS = n
 957         depends on SQUASHFS = n
 958         depends on SYSFS = n
 959         depends on SYSV_FS = n
 960         depends on TMPFS = n
 961         depends on UBIFS_FS = n
 962         depends on UDF_FS = n
 963         depends on UFS_FS = n
 964         depends on VXFS_FS = n
 965         depends on XFS_FS = n
 966
 967         depends on !UML || HOSTFS = n
 968
 969         # The rare drivers that won't build
 970         depends on AIRO = n
 971         depends on AIRO_CS = n
 972         depends on TUN = n
 973         depends on INFINIBAND_QIB = n
 974         depends on BLK_DEV_LOOP = n
 975         depends on ANDROID_BINDER_IPC = n
 976
 977         # Security modules
 978         depends on SECURITY_TOMOYO = n
 979         depends on SECURITY_APPARMOR = n
 980
 981 config UIDGID_STRICT_TYPE_CHECKS
 982         bool "Require conversions between uid/gids and their internal representation"
 983         depends on UIDGID_CONVERTED
 984         default n
 985         help
 986          While the nececessary conversions are being added to all subsystems this option allows
 987          the code to continue to build for unconverted subsystems.
 988
 989          Say Y here if you want the strict type checking enabled
 990
 991 config SCHED_AUTOGROUP
 992         bool "Automatic process group scheduling"
 993         select EVENTFD
 994         select CGROUPS
 995         select CGROUP_SCHED
 996         select FAIR_GROUP_SCHED
 997         help
 998           This option optimizes the scheduler for common desktop workloads by
 999           automatically creating and populating task groups.  This separation
1000           of workloads isolates aggressive CPU burners (like build jobs) from
1001           desktop applications.  Task group autogeneration is currently based
1002           upon task session.
1003
1004 config MM_OWNER
1005         bool
1006
1007 config SYSFS_DEPRECATED
1008         bool "Enable deprecated sysfs features to support old userspace tools"
1009         depends on SYSFS
1010         default n
1011         help
1012           This option adds code that switches the layout of the "block" class
1013           devices, to not show up in /sys/class/block/, but only in
1014           /sys/block/.
1015
1016           This switch is only active when the sysfs.deprecated=1 boot option is
1017           passed or the SYSFS_DEPRECATED_V2 option is set.
1018
1019           This option allows new kernels to run on old distributions and tools,
1020           which might get confused by /sys/class/block/. Since 2007/2008 all
1021           major distributions and tools handle this just fine.
1022
1023           Recent distributions and userspace tools after 2009/2010 depend on
1024           the existence of /sys/class/block/, and will not work with this
1025           option enabled.
1026
1027           Only if you are using a new kernel on an old distribution, you might
1028           need to say Y here.
1029
1030 config SYSFS_DEPRECATED_V2
1031         bool "Enable deprecated sysfs features by default"
1032         default n
1033         depends on SYSFS
1034         depends on SYSFS_DEPRECATED
1035         help
1036           Enable deprecated sysfs by default.
1037
1038           See the CONFIG_SYSFS_DEPRECATED option for more details about this
1039           option.
1040
1041           Only if you are using a new kernel on an old distribution, you might
1042           need to say Y here. Even then, odds are you would not need it
1043           enabled, you can always pass the boot option if absolutely necessary.
1044
1045 config RELAY
1046         bool "Kernel->user space relay support (formerly relayfs)"
1047         help
1048           This option enables support for relay interface support in
1049           certain file systems (such as debugfs).
1050           It is designed to provide an efficient mechanism for tools and
1051           facilities to relay large amounts of data from kernel space to
1052           user space.
1053
1054           If unsure, say N.
1055
1056 config BLK_DEV_INITRD
1057         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1058         depends on BROKEN || !FRV
1059         help
1060           The initial RAM filesystem is a ramfs which is loaded by the
1061           boot loader (loadlin or lilo) and that is mounted as root
1062           before the normal boot procedure. It is typically used to
1063           load modules needed to mount the "real" root file system,
1064           etc. See <file:Documentation/initrd.txt> for details.
1065
1066           If RAM disk support (BLK_DEV_RAM) is also included, this
1067           also enables initial RAM disk (initrd) support and adds
1068           15 Kbytes (more on some other architectures) to the kernel size.
1069
1070           If unsure say Y.
1071
1072 if BLK_DEV_INITRD
1073
1074 source "usr/Kconfig"
1075
1076 endif
1077
1078 config CC_OPTIMIZE_FOR_SIZE
1079         bool "Optimize for size"
1080         help
1081           Enabling this option will pass "-Os" instead of "-O2" to gcc
1082           resulting in a smaller kernel.
1083
1084           If unsure, say Y.
1085
1086 config SYSCTL
1087         bool
1088
1089 config ANON_INODES
1090         bool
1091
1092 menuconfig EXPERT
1093         bool "Configure standard kernel features (expert users)"
1094         # Unhide debug options, to make the on-by-default options visible
1095         select DEBUG_KERNEL
1096         help
1097           This option allows certain base kernel options and settings
1098           to be disabled or tweaked. This is for specialized
1099           environments which can tolerate a "non-standard" kernel.
1100           Only use this if you really know what you are doing.
1101
1102 config UID16
1103         bool "Enable 16-bit UID system calls" if EXPERT
1104         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
1105         default y
1106         help
1107           This enables the legacy 16-bit UID syscall wrappers.
1108
1109 config SYSCTL_SYSCALL
1110         bool "Sysctl syscall support" if EXPERT
1111         depends on PROC_SYSCTL
1112         default n
1113         select SYSCTL
1114         ---help---
1115           sys_sysctl uses binary paths that have been found challenging
1116           to properly maintain and use.  The interface in /proc/sys
1117           using paths with ascii names is now the primary path to this
1118           information.
1119
1120           Almost nothing using the binary sysctl interface so if you are
1121           trying to save some space it is probably safe to disable this,
1122           making your kernel marginally smaller.
1123
1124           If unsure say N here.
1125
1126 config KALLSYMS
1127          bool "Load all symbols for debugging/ksymoops" if EXPERT
1128          default y
1129          help
1130            Say Y here to let the kernel print out symbolic crash information and
1131            symbolic stack backtraces. This increases the size of the kernel
1132            somewhat, as all symbols have to be loaded into the kernel image.
1133
1134 config KALLSYMS_ALL
1135         bool "Include all symbols in kallsyms"
1136         depends on DEBUG_KERNEL && KALLSYMS
1137         help
1138            Normally kallsyms only contains the symbols of functions for nicer
1139            OOPS messages and backtraces (i.e., symbols from the text and inittext
1140            sections). This is sufficient for most cases. And only in very rare
1141            cases (e.g., when a debugger is used) all symbols are required (e.g.,
1142            names of variables from the data sections, etc).
1143
1144            This option makes sure that all symbols are loaded into the kernel
1145            image (i.e., symbols from all sections) in cost of increased kernel
1146            size (depending on the kernel configuration, it may be 300KiB or
1147            something like this).
1148
1149            Say N unless you really need all symbols.
1150
1151 config HOTPLUG
1152         bool "Support for hot-pluggable devices" if EXPERT
1153         default y
1154         help
1155           This option is provided for the case where no hotplug or uevent
1156           capabilities is wanted by the kernel.  You should only consider
1157           disabling this option for embedded systems that do not use modules, a
1158           dynamic /dev tree, or dynamic device discovery.  Just say Y.
1159
1160 config PRINTK
1161         default y
1162         bool "Enable support for printk" if EXPERT
1163         help
1164           This option enables normal printk support. Removing it
1165           eliminates most of the message strings from the kernel image
1166           and makes the kernel more or less silent. As this makes it
1167           very difficult to diagnose system problems, saying N here is
1168           strongly discouraged.
1169
1170 config BUG
1171         bool "BUG() support" if EXPERT
1172         default y
1173         help
1174           Disabling this option eliminates support for BUG and WARN, reducing
1175           the size of your kernel image and potentially quietly ignoring
1176           numerous fatal conditions. You should only consider disabling this
1177           option for embedded systems with no facilities for reporting errors.
1178           Just say Y.
1179
1180 config ELF_CORE
1181         default y
1182         bool "Enable ELF core dumps" if EXPERT
1183         help
1184           Enable support for generating core dumps. Disabling saves about 4k.
1185
1186
1187 config PCSPKR_PLATFORM
1188         bool "Enable PC-Speaker support" if EXPERT
1189         depends on HAVE_PCSPKR_PLATFORM
1190         select I8253_LOCK
1191         default y
1192         help
1193           This option allows to disable the internal PC-Speaker
1194           support, saving some memory.
1195
1196 config HAVE_PCSPKR_PLATFORM
1197         bool
1198
1199 config BASE_FULL
1200         default y
1201         bool "Enable full-sized data structures for core" if EXPERT
1202         help
1203           Disabling this option reduces the size of miscellaneous core
1204           kernel data structures. This saves memory on small machines,
1205           but may reduce performance.
1206
1207 config FUTEX
1208         bool "Enable futex support" if EXPERT
1209         default y
1210         select RT_MUTEXES
1211         help
1212           Disabling this option will cause the kernel to be built without
1213           support for "fast userspace mutexes".  The resulting kernel may not
1214           run glibc-based applications correctly.
1215
1216 config EPOLL
1217         bool "Enable eventpoll support" if EXPERT
1218         default y
1219         select ANON_INODES
1220         help
1221           Disabling this option will cause the kernel to be built without
1222           support for epoll family of system calls.
1223
1224 config SIGNALFD
1225         bool "Enable signalfd() system call" if EXPERT
1226         select ANON_INODES
1227         default y
1228         help
1229           Enable the signalfd() system call that allows to receive signals
1230           on a file descriptor.
1231
1232           If unsure, say Y.
1233
1234 config TIMERFD
1235         bool "Enable timerfd() system call" if EXPERT
1236         select ANON_INODES
1237         default y
1238         help
1239           Enable the timerfd() system call that allows to receive timer
1240           events on a file descriptor.
1241
1242           If unsure, say Y.
1243
1244 config EVENTFD
1245         bool "Enable eventfd() system call" if EXPERT
1246         select ANON_INODES
1247         default y
1248         help
1249           Enable the eventfd() system call that allows to receive both
1250           kernel notification (ie. KAIO) or userspace notifications.
1251
1252           If unsure, say Y.
1253
1254 config SHMEM
1255         bool "Use full shmem filesystem" if EXPERT
1256         default y
1257         depends on MMU
1258         help
1259           The shmem is an internal filesystem used to manage shared memory.
1260           It is backed by swap and manages resource limits. It is also exported
1261           to userspace as tmpfs if TMPFS is enabled. Disabling this
1262           option replaces shmem and tmpfs with the much simpler ramfs code,
1263           which may be appropriate on small systems without swap.
1264
1265 config AIO
1266         bool "Enable AIO support" if EXPERT
1267         default y
1268         help
1269           This option enables POSIX asynchronous I/O which may by used
1270           by some high performance threaded applications. Disabling
1271           this option saves about 7k.
1272
1273 config EMBEDDED
1274         bool "Embedded system"
1275         select EXPERT
1276         help
1277           This option should be enabled if compiling the kernel for
1278           an embedded system so certain expert options are available
1279           for configuration.
1280
1281 config HAVE_PERF_EVENTS
1282         bool
1283         help
1284           See tools/perf/design.txt for details.
1285
1286 config PERF_USE_VMALLOC
1287         bool
1288         help
1289           See tools/perf/design.txt for details
1290
1291 menu "Kernel Performance Events And Counters"
1292
1293 config PERF_EVENTS
1294         bool "Kernel performance events and counters"
1295         default y if (PROFILING || PERF_COUNTERS)
1296         depends on HAVE_PERF_EVENTS
1297         select ANON_INODES
1298         select IRQ_WORK
1299         help
1300           Enable kernel support for various performance events provided
1301           by software and hardware.
1302
1303           Software events are supported either built-in or via the
1304           use of generic tracepoints.
1305
1306           Most modern CPUs support performance events via performance
1307           counter registers. These registers count the number of certain
1308           types of hw events: such as instructions executed, cachemisses
1309           suffered, or branches mis-predicted - without slowing down the
1310           kernel or applications. These registers can also trigger interrupts
1311           when a threshold number of events have passed - and can thus be
1312           used to profile the code that runs on that CPU.
1313
1314           The Linux Performance Event subsystem provides an abstraction of
1315           these software and hardware event capabilities, available via a
1316           system call and used by the "perf" utility in tools/perf/. It
1317           provides per task and per CPU counters, and it provides event
1318           capabilities on top of those.
1319
1320           Say Y if unsure.
1321
1322 config PERF_COUNTERS
1323         bool "Kernel performance counters (old config option)"
1324         depends on HAVE_PERF_EVENTS
1325         help
1326           This config has been obsoleted by the PERF_EVENTS
1327           config option - please see that one for details.
1328
1329           It has no effect on the kernel whether you enable
1330           it or not, it is a compatibility placeholder.
1331
1332           Say N if unsure.
1333
1334 config DEBUG_PERF_USE_VMALLOC
1335         default n
1336         bool "Debug: use vmalloc to back perf mmap() buffers"
1337         depends on PERF_EVENTS && DEBUG_KERNEL
1338         select PERF_USE_VMALLOC
1339         help
1340          Use vmalloc memory to back perf mmap() buffers.
1341
1342          Mostly useful for debugging the vmalloc code on platforms
1343          that don't require it.
1344
1345          Say N if unsure.
1346
1347 endmenu
1348
1349 config VM_EVENT_COUNTERS
1350         default y
1351         bool "Enable VM event counters for /proc/vmstat" if EXPERT
1352         help
1353           VM event counters are needed for event counts to be shown.
1354           This option allows the disabling of the VM event counters
1355           on EXPERT systems.  /proc/vmstat will only show page counts
1356           if VM event counters are disabled.
1357
1358 config PCI_QUIRKS
1359         default y
1360         bool "Enable PCI quirk workarounds" if EXPERT
1361         depends on PCI
1362         help
1363           This enables workarounds for various PCI chipset
1364           bugs/quirks. Disable this only if your target machine is
1365           unaffected by PCI quirks.
1366
1367 config SLUB_DEBUG
1368         default y
1369         bool "Enable SLUB debugging support" if EXPERT
1370         depends on SLUB && SYSFS
1371         help
1372           SLUB has extensive debug support features. Disabling these can
1373           result in significant savings in code size. This also disables
1374           SLUB sysfs support. /sys/slab will not exist and there will be
1375           no support for cache validation etc.
1376
1377 config COMPAT_BRK
1378         bool "Disable heap randomization"
1379         default y
1380         help
1381           Randomizing heap placement makes heap exploits harder, but it
1382           also breaks ancient binaries (including anything libc5 based).
1383           This option changes the bootup default to heap randomization
1384           disabled, and can be overridden at runtime by setting
1385           /proc/sys/kernel/randomize_va_space to 2.
1386
1387           On non-ancient distros (post-2000 ones) N is usually a safe choice.
1388
1389 choice
1390         prompt "Choose SLAB allocator"
1391         default SLUB
1392         help
1393            This option allows to select a slab allocator.
1394
1395 config SLAB
1396         bool "SLAB"
1397         help
1398           The regular slab allocator that is established and known to work
1399           well in all environments. It organizes cache hot objects in
1400           per cpu and per node queues.
1401
1402 config SLUB
1403         bool "SLUB (Unqueued Allocator)"
1404         help
1405            SLUB is a slab allocator that minimizes cache line usage
1406            instead of managing queues of cached objects (SLAB approach).
1407            Per cpu caching is realized using slabs of objects instead
1408            of queues of objects. SLUB can use memory efficiently
1409            and has enhanced diagnostics. SLUB is the default choice for
1410            a slab allocator.
1411
1412 config SLOB
1413         depends on EXPERT
1414         bool "SLOB (Simple Allocator)"
1415         help
1416            SLOB replaces the stock allocator with a drastically simpler
1417            allocator. SLOB is generally more space efficient but
1418            does not perform as well on large systems.
1419
1420 endchoice
1421
1422 config MMAP_ALLOW_UNINITIALIZED
1423         bool "Allow mmapped anonymous memory to be uninitialized"
1424         depends on EXPERT && !MMU
1425         default n
1426         help
1427           Normally, and according to the Linux spec, anonymous memory obtained
1428           from mmap() has it's contents cleared before it is passed to
1429           userspace.  Enabling this config option allows you to request that
1430           mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1431           providing a huge performance boost.  If this option is not enabled,
1432           then the flag will be ignored.
1433
1434           This is taken advantage of by uClibc's malloc(), and also by
1435           ELF-FDPIC binfmt's brk and stack allocator.
1436
1437           Because of the obvious security issues, this option should only be
1438           enabled on embedded devices where you control what is run in
1439           userspace.  Since that isn't generally a problem on no-MMU systems,
1440           it is normally safe to say Y here.
1441
1442           See Documentation/nommu-mmap.txt for more information.
1443
1444 config PROFILING
1445         bool "Profiling support"
1446         help
1447           Say Y here to enable the extended profiling support mechanisms used
1448           by profilers such as OProfile.
1449
1450 #
1451 # Place an empty function call at each tracepoint site. Can be
1452 # dynamically changed for a probe function.
1453 #
1454 config TRACEPOINTS
1455         bool
1456
1457 source "arch/Kconfig"
1458
1459 endmenu         # General setup
1460
1461 config HAVE_GENERIC_DMA_COHERENT
1462         bool
1463         default n
1464
1465 config SLABINFO
1466         bool
1467         depends on PROC_FS
1468         depends on SLAB || SLUB_DEBUG
1469         default y
1470
1471 config RT_MUTEXES
1472         boolean
1473
1474 config BASE_SMALL
1475         int
1476         default 0 if BASE_FULL
1477         default 1 if !BASE_FULL
1478
1479 menuconfig MODULES
1480         bool "Enable loadable module support"
1481         help
1482           Kernel modules are small pieces of compiled code which can
1483           be inserted in the running kernel, rather than being
1484           permanently built into the kernel.  You use the "modprobe"
1485           tool to add (and sometimes remove) them.  If you say Y here,
1486           many parts of the kernel can be built as modules (by
1487           answering M instead of Y where indicated): this is most
1488           useful for infrequently used options which are not required
1489           for booting.  For more information, see the man pages for
1490           modprobe, lsmod, modinfo, insmod and rmmod.
1491
1492           If you say Y here, you will need to run "make
1493           modules_install" to put the modules under /lib/modules/
1494           where modprobe can find them (you may need to be root to do
1495           this).
1496
1497           If unsure, say Y.
1498
1499 if MODULES
1500
1501 config MODULE_FORCE_LOAD
1502         bool "Forced module loading"
1503         default n
1504         help
1505           Allow loading of modules without version information (ie. modprobe
1506           --force).  Forced module loading sets the 'F' (forced) taint flag and
1507           is usually a really bad idea.
1508
1509 config MODULE_UNLOAD
1510         bool "Module unloading"
1511         help
1512           Without this option you will not be able to unload any
1513           modules (note that some modules may not be unloadable
1514           anyway), which makes your kernel smaller, faster
1515           and simpler.  If unsure, say Y.
1516
1517 config MODULE_FORCE_UNLOAD
1518         bool "Forced module unloading"
1519         depends on MODULE_UNLOAD && EXPERIMENTAL
1520         help
1521           This option allows you to force a module to unload, even if the
1522           kernel believes it is unsafe: the kernel will remove the module
1523           without waiting for anyone to stop using it (using the -f option to
1524           rmmod).  This is mainly for kernel developers and desperate users.
1525           If unsure, say N.
1526
1527 config MODVERSIONS
1528         bool "Module versioning support"
1529         help
1530           Usually, you have to use modules compiled with your kernel.
1531           Saying Y here makes it sometimes possible to use modules
1532           compiled for different kernels, by adding enough information
1533           to the modules to (hopefully) spot any changes which would
1534           make them incompatible with the kernel you are running.  If
1535           unsure, say N.
1536
1537 config MODULE_SRCVERSION_ALL
1538         bool "Source checksum for all modules"
1539         help
1540           Modules which contain a MODULE_VERSION get an extra "srcversion"
1541           field inserted into their modinfo section, which contains a
1542           sum of the source files which made it.  This helps maintainers
1543           see exactly which source was used to build a module (since
1544           others sometimes change the module source without updating
1545           the version).  With this option, such a "srcversion" field
1546           will be created for all modules.  If unsure, say N.
1547
1548 endif # MODULES
1549
1550 config INIT_ALL_POSSIBLE
1551         bool
1552         help
1553           Back when each arch used to define their own cpu_online_map and
1554           cpu_possible_map, some of them chose to initialize cpu_possible_map
1555           with all 1s, and others with all 0s.  When they were centralised,
1556           it was better to provide this option than to break all the archs
1557           and have several arch maintainers pursuing me down dark alleys.
1558
1559 config STOP_MACHINE
1560         bool
1561         default y
1562         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1563         help
1564           Need stop_machine() primitive.
1565
1566 source "block/Kconfig"
1567
1568 config PREEMPT_NOTIFIERS
1569         bool
1570
1571 config PADATA
1572         depends on SMP
1573         bool
1574
1575 source "kernel/Kconfig.locks"