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  53           drivers that have been replaced by something else, and/or are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_LEAF
 462         int "Tree-based hierarchical RCU leaf-level fanout value"
 463         range 2 RCU_FANOUT if 64BIT
 464         range 2 RCU_FANOUT if !64BIT
 465         depends on TREE_RCU || TREE_PREEMPT_RCU
 466         default 16
 467         help
 468           This option controls the leaf-level fanout of hierarchical
 469           implementations of RCU, and allows trading off cache misses
 470           against lock contention.  Systems that synchronize their
 471           scheduling-clock interrupts for energy-efficiency reasons will
 472           want the default because the smaller leaf-level fanout keeps
 473           lock contention levels acceptably low.  Very large systems
 474           (hundreds or thousands of CPUs) will instead want to set this
 475           value to the maximum value possible in order to reduce the
 476           number of cache misses incurred during RCU's grace-period
 477           initialization.  These systems tend to run CPU-bound, and thus
 478           are not helped by synchronized interrupts, and thus tend to
 479           skew them, which reduces lock contention enough that large
 480           leaf-level fanouts work well.
 481
 482           Select a specific number if testing RCU itself.
 483
 484           Select the maximum permissible value for large systems.
 485
 486           Take the default if unsure.
 487
 488 config RCU_FANOUT_EXACT
 489         bool "Disable tree-based hierarchical RCU auto-balancing"
 490         depends on TREE_RCU || TREE_PREEMPT_RCU
 491         default n
 492         help
 493           This option forces use of the exact RCU_FANOUT value specified,
 494           regardless of imbalances in the hierarchy.  This is useful for
 495           testing RCU itself, and might one day be useful on systems with
 496           strong NUMA behavior.
 497
 498           Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 499
 500           Say N if unsure.
 501
 502 config RCU_FAST_NO_HZ
 503         bool "Accelerate last non-dyntick-idle CPU's grace periods"
 504         depends on NO_HZ && SMP
 505         default n
 506         help
 507           This option causes RCU to attempt to accelerate grace periods
 508           in order to allow CPUs to enter dynticks-idle state more
 509           quickly.  On the other hand, this option increases the overhead
 510           of the dynticks-idle checking, particularly on systems with
 511           large numbers of CPUs.
 512
 513           Say Y if energy efficiency is critically important, particularly
 514                 if you have relatively few CPUs.
 515
 516           Say N if you are unsure.
 517
 518 config TREE_RCU_TRACE
 519         def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 520         select DEBUG_FS
 521         help
 522           This option provides tracing for the TREE_RCU and
 523           TREE_PREEMPT_RCU implementations, permitting Makefile to
 524           trivially select kernel/rcutree_trace.c.
 525
 526 config RCU_BOOST
 527         bool "Enable RCU priority boosting"
 528         depends on RT_MUTEXES && PREEMPT_RCU
 529         default n
 530         help
 531           This option boosts the priority of preempted RCU readers that
 532           block the current preemptible RCU grace period for too long.
 533           This option also prevents heavy loads from blocking RCU
 534           callback invocation for all flavors of RCU.
 535
 536           Say Y here if you are working with real-time apps or heavy loads
 537           Say N here if you are unsure.
 538
 539 config RCU_BOOST_PRIO
 540         int "Real-time priority to boost RCU readers to"
 541         range 1 99
 542         depends on RCU_BOOST
 543         default 1
 544         help
 545           This option specifies the real-time priority to which long-term
 546           preempted RCU readers are to be boosted.  If you are working
 547           with a real-time application that has one or more CPU-bound
 548           threads running at a real-time priority level, you should set
 549           RCU_BOOST_PRIO to a priority higher then the highest-priority
 550           real-time CPU-bound thread.  The default RCU_BOOST_PRIO value
 551           of 1 is appropriate in the common case, which is real-time
 552           applications that do not have any CPU-bound threads.
 553
 554           Some real-time applications might not have a single real-time
 555           thread that saturates a given CPU, but instead might have
 556           multiple real-time threads that, taken together, fully utilize
 557           that CPU.  In this case, you should set RCU_BOOST_PRIO to
 558           a priority higher than the lowest-priority thread that is
 559           conspiring to prevent the CPU from running any non-real-time
 560           tasks.  For example, if one thread at priority 10 and another
 561           thread at priority 5 are between themselves fully consuming
 562           the CPU time on a given CPU, then RCU_BOOST_PRIO should be
 563           set to priority 6 or higher.
 564
 565           Specify the real-time priority, or take the default if unsure.
 566
 567 config RCU_BOOST_DELAY
 568         int "Milliseconds to delay boosting after RCU grace-period start"
 569         range 0 3000
 570         depends on RCU_BOOST
 571         default 500
 572         help
 573           This option specifies the time to wait after the beginning of
 574           a given grace period before priority-boosting preempted RCU
 575           readers blocking that grace period.  Note that any RCU reader
 576           blocking an expedited RCU grace period is boosted immediately.
 577
 578           Accept the default if unsure.
 579
 580 endmenu # "RCU Subsystem"
 581
 582 config IKCONFIG
 583         tristate "Kernel .config support"
 584         ---help---
 585           This option enables the complete Linux kernel ".config" file
 586           contents to be saved in the kernel. It provides documentation
 587           of which kernel options are used in a running kernel or in an
 588           on-disk kernel.  This information can be extracted from the kernel
 589           image file with the script scripts/extract-ikconfig and used as
 590           input to rebuild the current kernel or to build another kernel.
 591           It can also be extracted from a running kernel by reading
 592           /proc/config.gz if enabled (below).
 593
 594 config IKCONFIG_PROC
 595         bool "Enable access to .config through /proc/config.gz"
 596         depends on IKCONFIG && PROC_FS
 597         ---help---
 598           This option enables access to the kernel configuration file
 599           through /proc/config.gz.
 600
 601 config LOG_BUF_SHIFT
 602         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 603         range 12 21
 604         default 17
 605         help
 606           Select kernel log buffer size as a power of 2.
 607           Examples:
 608                      17 => 128 KB
 609                      16 => 64 KB
 610                      15 => 32 KB
 611                      14 => 16 KB
 612                      13 =>  8 KB
 613                      12 =>  4 KB
 614
 615 #
 616 # Architectures with an unreliable sched_clock() should select this:
 617 #
 618 config HAVE_UNSTABLE_SCHED_CLOCK
 619         bool
 620
 621 menuconfig CGROUPS
 622         boolean "Control Group support"
 623         depends on EVENTFD
 624         help
 625           This option adds support for grouping sets of processes together, for
 626           use with process control subsystems such as Cpusets, CFS, memory
 627           controls or device isolation.
 628           See
 629                 - Documentation/scheduler/sched-design-CFS.txt  (CFS)
 630                 - Documentation/cgroups/ (features for grouping, isolation
 631                                           and resource control)
 632
 633           Say N if unsure.
 634
 635 if CGROUPS
 636
 637 config CGROUP_DEBUG
 638         bool "Example debug cgroup subsystem"
 639         default n
 640         help
 641           This option enables a simple cgroup subsystem that
 642           exports useful debugging information about the cgroups
 643           framework.
 644
 645           Say N if unsure.
 646
 647 config CGROUP_FREEZER
 648         bool "Freezer cgroup subsystem"
 649         help
 650           Provides a way to freeze and unfreeze all tasks in a
 651           cgroup.
 652
 653 config CGROUP_DEVICE
 654         bool "Device controller for cgroups"
 655         help
 656           Provides a cgroup implementing whitelists for devices which
 657           a process in the cgroup can mknod or open.
 658
 659 config CPUSETS
 660         bool "Cpuset support"
 661         help
 662           This option will let you create and manage CPUSETs which
 663           allow dynamically partitioning a system into sets of CPUs and
 664           Memory Nodes and assigning tasks to run only within those sets.
 665           This is primarily useful on large SMP or NUMA systems.
 666
 667           Say N if unsure.
 668
 669 config PROC_PID_CPUSET
 670         bool "Include legacy /proc/<pid>/cpuset file"
 671         depends on CPUSETS
 672         default y
 673
 674 config CGROUP_CPUACCT
 675         bool "Simple CPU accounting cgroup subsystem"
 676         help
 677           Provides a simple Resource Controller for monitoring the
 678           total CPU consumed by the tasks in a cgroup.
 679
 680 config RESOURCE_COUNTERS
 681         bool "Resource counters"
 682         help
 683           This option enables controller independent resource accounting
 684           infrastructure that works with cgroups.
 685
 686 config CGROUP_MEM_RES_CTLR
 687         bool "Memory Resource Controller for Control Groups"
 688         depends on RESOURCE_COUNTERS
 689         select MM_OWNER
 690         help
 691           Provides a memory resource controller that manages both anonymous
 692           memory and page cache. (See Documentation/cgroups/memory.txt)
 693
 694           Note that setting this option increases fixed memory overhead
 695           associated with each page of memory in the system. By this,
 696           20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 697           usage tracking struct at boot. Total amount of this is printed out
 698           at boot.
 699
 700           Only enable when you're ok with these trade offs and really
 701           sure you need the memory resource controller. Even when you enable
 702           this, you can set "cgroup_disable=memory" at your boot option to
 703           disable memory resource controller and you can avoid overheads.
 704           (and lose benefits of memory resource controller)
 705
 706           This config option also selects MM_OWNER config option, which
 707           could in turn add some fork/exit overhead.
 708
 709 config CGROUP_MEM_RES_CTLR_SWAP
 710         bool "Memory Resource Controller Swap Extension"
 711         depends on CGROUP_MEM_RES_CTLR && SWAP
 712         help
 713           Add swap management feature to memory resource controller. When you
 714           enable this, you can limit mem+swap usage per cgroup. In other words,
 715           when you disable this, memory resource controller has no cares to
 716           usage of swap...a process can exhaust all of the swap. This extension
 717           is useful when you want to avoid exhaustion swap but this itself
 718           adds more overheads and consumes memory for remembering information.
 719           Especially if you use 32bit system or small memory system, please
 720           be careful about enabling this. When memory resource controller
 721           is disabled by boot option, this will be automatically disabled and
 722           there will be no overhead from this. Even when you set this config=y,
 723           if boot option "swapaccount=0" is set, swap will not be accounted.
 724           Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 725           size is 4096bytes, 512k per 1Gbytes of swap.
 726 config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
 727         bool "Memory Resource Controller Swap Extension enabled by default"
 728         depends on CGROUP_MEM_RES_CTLR_SWAP
 729         default y
 730         help
 731           Memory Resource Controller Swap Extension comes with its price in
 732           a bigger memory consumption. General purpose distribution kernels
 733           which want to enable the feature but keep it disabled by default
 734           and let the user enable it by swapaccount boot command line
 735           parameter should have this option unselected.
 736           For those who want to have the feature enabled by default should
 737           select this option (if, for some reason, they need to disable it
 738           then swapaccount=0 does the trick).
 739 config CGROUP_MEM_RES_CTLR_KMEM
 740         bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 741         depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
 742         default n
 743         help
 744           The Kernel Memory extension for Memory Resource Controller can limit
 745           the amount of memory used by kernel objects in the system. Those are
 746           fundamentally different from the entities handled by the standard
 747           Memory Controller, which are page-based, and can be swapped. Users of
 748           the kmem extension can use it to guarantee that no group of processes
 749           will ever exhaust kernel resources alone.
 750
 751 config CGROUP_PERF
 752         bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 753         depends on PERF_EVENTS && CGROUPS
 754         help
 755           This option extends the per-cpu mode to restrict monitoring to
 756           threads which belong to the cgroup specified and run on the
 757           designated cpu.
 758
 759           Say N if unsure.
 760
 761 menuconfig CGROUP_SCHED
 762         bool "Group CPU scheduler"
 763         default n
 764         help
 765           This feature lets CPU scheduler recognize task groups and control CPU
 766           bandwidth allocation to such task groups. It uses cgroups to group
 767           tasks.
 768
 769 if CGROUP_SCHED
 770 config FAIR_GROUP_SCHED
 771         bool "Group scheduling for SCHED_OTHER"
 772         depends on CGROUP_SCHED
 773         default CGROUP_SCHED
 774
 775 config CFS_BANDWIDTH
 776         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 777         depends on EXPERIMENTAL
 778         depends on FAIR_GROUP_SCHED
 779         default n
 780         help
 781           This option allows users to define CPU bandwidth rates (limits) for
 782           tasks running within the fair group scheduler.  Groups with no limit
 783           set are considered to be unconstrained and will run with no
 784           restriction.
 785           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 786
 787 config RT_GROUP_SCHED
 788         bool "Group scheduling for SCHED_RR/FIFO"
 789         depends on EXPERIMENTAL
 790         depends on CGROUP_SCHED
 791         default n
 792         help
 793           This feature lets you explicitly allocate real CPU bandwidth
 794           to task groups. If enabled, it will also make it impossible to
 795           schedule realtime tasks for non-root users until you allocate
 796           realtime bandwidth for them.
 797           See Documentation/scheduler/sched-rt-group.txt for more information.
 798
 799 endif #CGROUP_SCHED
 800
 801 config BLK_CGROUP
 802         tristate "Block IO controller"
 803         depends on BLOCK
 804         default n
 805         ---help---
 806         Generic block IO controller cgroup interface. This is the common
 807         cgroup interface which should be used by various IO controlling
 808         policies.
 809
 810         Currently, CFQ IO scheduler uses it to recognize task groups and
 811         control disk bandwidth allocation (proportional time slice allocation)
 812         to such task groups. It is also used by bio throttling logic in
 813         block layer to implement upper limit in IO rates on a device.
 814
 815         This option only enables generic Block IO controller infrastructure.
 816         One needs to also enable actual IO controlling logic/policy. For
 817         enabling proportional weight division of disk bandwidth in CFQ, set
 818         CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 819         CONFIG_BLK_DEV_THROTTLING=y.
 820
 821         See Documentation/cgroups/blkio-controller.txt for more information.
 822
 823 config DEBUG_BLK_CGROUP
 824         bool "Enable Block IO controller debugging"
 825         depends on BLK_CGROUP
 826         default n
 827         ---help---
 828         Enable some debugging help. Currently it exports additional stat
 829         files in a cgroup which can be useful for debugging.
 830
 831 endif # CGROUPS
 832
 833 config CHECKPOINT_RESTORE
 834         bool "Checkpoint/restore support" if EXPERT
 835         default n
 836         help
 837           Enables additional kernel features in a sake of checkpoint/restore.
 838           In particular it adds auxiliary prctl codes to setup process text,
 839           data and heap segment sizes, and a few additional /proc filesystem
 840           entries.
 841
 842           If unsure, say N here.
 843
 844 menuconfig NAMESPACES
 845         bool "Namespaces support" if EXPERT
 846         default !EXPERT
 847         help
 848           Provides the way to make tasks work with different objects using
 849           the same id. For example same IPC id may refer to different objects
 850           or same user id or pid may refer to different tasks when used in
 851           different namespaces.
 852
 853 if NAMESPACES
 854
 855 config UTS_NS
 856         bool "UTS namespace"
 857         default y
 858         help
 859           In this namespace tasks see different info provided with the
 860           uname() system call
 861
 862 config IPC_NS
 863         bool "IPC namespace"
 864         depends on (SYSVIPC || POSIX_MQUEUE)
 865         default y
 866         help
 867           In this namespace tasks work with IPC ids which correspond to
 868           different IPC objects in different namespaces.
 869
 870 config USER_NS
 871         bool "User namespace (EXPERIMENTAL)"
 872         depends on EXPERIMENTAL
 873         default y
 874         help
 875           This allows containers, i.e. vservers, to use user namespaces
 876           to provide different user info for different servers.
 877           If unsure, say N.
 878
 879 config PID_NS
 880         bool "PID Namespaces"
 881         default y
 882         help
 883           Support process id namespaces.  This allows having multiple
 884           processes with the same pid as long as they are in different
 885           pid namespaces.  This is a building block of containers.
 886
 887 config NET_NS
 888         bool "Network namespace"
 889         depends on NET
 890         default y
 891         help
 892           Allow user space to create what appear to be multiple instances
 893           of the network stack.
 894
 895 endif # NAMESPACES
 896
 897 config SCHED_AUTOGROUP
 898         bool "Automatic process group scheduling"
 899         select EVENTFD
 900         select CGROUPS
 901         select CGROUP_SCHED
 902         select FAIR_GROUP_SCHED
 903         help
 904           This option optimizes the scheduler for common desktop workloads by
 905           automatically creating and populating task groups.  This separation
 906           of workloads isolates aggressive CPU burners (like build jobs) from
 907           desktop applications.  Task group autogeneration is currently based
 908           upon task session.
 909
 910 config MM_OWNER
 911         bool
 912
 913 config SYSFS_DEPRECATED
 914         bool "Enable deprecated sysfs features to support old userspace tools"
 915         depends on SYSFS
 916         default n
 917         help
 918           This option adds code that switches the layout of the "block" class
 919           devices, to not show up in /sys/class/block/, but only in
 920           /sys/block/.
 921
 922           This switch is only active when the sysfs.deprecated=1 boot option is
 923           passed or the SYSFS_DEPRECATED_V2 option is set.
 924
 925           This option allows new kernels to run on old distributions and tools,
 926           which might get confused by /sys/class/block/. Since 2007/2008 all
 927           major distributions and tools handle this just fine.
 928
 929           Recent distributions and userspace tools after 2009/2010 depend on
 930           the existence of /sys/class/block/, and will not work with this
 931           option enabled.
 932
 933           Only if you are using a new kernel on an old distribution, you might
 934           need to say Y here.
 935
 936 config SYSFS_DEPRECATED_V2
 937         bool "Enable deprecated sysfs features by default"
 938         default n
 939         depends on SYSFS
 940         depends on SYSFS_DEPRECATED
 941         help
 942           Enable deprecated sysfs by default.
 943
 944           See the CONFIG_SYSFS_DEPRECATED option for more details about this
 945           option.
 946
 947           Only if you are using a new kernel on an old distribution, you might
 948           need to say Y here. Even then, odds are you would not need it
 949           enabled, you can always pass the boot option if absolutely necessary.
 950
 951 config RELAY
 952         bool "Kernel->user space relay support (formerly relayfs)"
 953         help
 954           This option enables support for relay interface support in
 955           certain file systems (such as debugfs).
 956           It is designed to provide an efficient mechanism for tools and
 957           facilities to relay large amounts of data from kernel space to
 958           user space.
 959
 960           If unsure, say N.
 961
 962 config BLK_DEV_INITRD
 963         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 964         depends on BROKEN || !FRV
 965         help
 966           The initial RAM filesystem is a ramfs which is loaded by the
 967           boot loader (loadlin or lilo) and that is mounted as root
 968           before the normal boot procedure. It is typically used to
 969           load modules needed to mount the "real" root file system,
 970           etc. See <file:Documentation/initrd.txt> for details.
 971
 972           If RAM disk support (BLK_DEV_RAM) is also included, this
 973           also enables initial RAM disk (initrd) support and adds
 974           15 Kbytes (more on some other architectures) to the kernel size.
 975
 976           If unsure say Y.
 977
 978 if BLK_DEV_INITRD
 979
 980 source "usr/Kconfig"
 981
 982 endif
 983
 984 config CC_OPTIMIZE_FOR_SIZE
 985         bool "Optimize for size"
 986         help
 987           Enabling this option will pass "-Os" instead of "-O2" to gcc
 988           resulting in a smaller kernel.
 989
 990           If unsure, say Y.
 991
 992 config SYSCTL
 993         bool
 994
 995 config ANON_INODES
 996         bool
 997
 998 menuconfig EXPERT
 999         bool "Configure standard kernel features (expert users)"
1000         # Unhide debug options, to make the on-by-default options visible
1001         select DEBUG_KERNEL
1002         help
1003           This option allows certain base kernel options and settings
1004           to be disabled or tweaked. This is for specialized
1005           environments which can tolerate a "non-standard" kernel.
1006           Only use this if you really know what you are doing.
1007
1008 config UID16
1009         bool "Enable 16-bit UID system calls" if EXPERT
1010         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
1011         default y
1012         help
1013           This enables the legacy 16-bit UID syscall wrappers.
1014
1015 config SYSCTL_SYSCALL
1016         bool "Sysctl syscall support" if EXPERT
1017         depends on PROC_SYSCTL
1018         default n
1019         select SYSCTL
1020         ---help---
1021           sys_sysctl uses binary paths that have been found challenging
1022           to properly maintain and use.  The interface in /proc/sys
1023           using paths with ascii names is now the primary path to this
1024           information.
1025
1026           Almost nothing using the binary sysctl interface so if you are
1027           trying to save some space it is probably safe to disable this,
1028           making your kernel marginally smaller.
1029
1030           If unsure say N here.
1031
1032 config KALLSYMS
1033          bool "Load all symbols for debugging/ksymoops" if EXPERT
1034          default y
1035          help
1036            Say Y here to let the kernel print out symbolic crash information and
1037            symbolic stack backtraces. This increases the size of the kernel
1038            somewhat, as all symbols have to be loaded into the kernel image.
1039
1040 config KALLSYMS_ALL
1041         bool "Include all symbols in kallsyms"
1042         depends on DEBUG_KERNEL && KALLSYMS
1043         help
1044            Normally kallsyms only contains the symbols of functions for nicer
1045            OOPS messages and backtraces (i.e., symbols from the text and inittext
1046            sections). This is sufficient for most cases. And only in very rare
1047            cases (e.g., when a debugger is used) all symbols are required (e.g.,
1048            names of variables from the data sections, etc).
1049
1050            This option makes sure that all symbols are loaded into the kernel
1051            image (i.e., symbols from all sections) in cost of increased kernel
1052            size (depending on the kernel configuration, it may be 300KiB or
1053            something like this).
1054
1055            Say N unless you really need all symbols.
1056
1057 config HOTPLUG
1058         bool "Support for hot-pluggable devices" if EXPERT
1059         default y
1060         help
1061           This option is provided for the case where no hotplug or uevent
1062           capabilities is wanted by the kernel.  You should only consider
1063           disabling this option for embedded systems that do not use modules, a
1064           dynamic /dev tree, or dynamic device discovery.  Just say Y.
1065
1066 config PRINTK
1067         default y
1068         bool "Enable support for printk" if EXPERT
1069         help
1070           This option enables normal printk support. Removing it
1071           eliminates most of the message strings from the kernel image
1072           and makes the kernel more or less silent. As this makes it
1073           very difficult to diagnose system problems, saying N here is
1074           strongly discouraged.
1075
1076 config BUG
1077         bool "BUG() support" if EXPERT
1078         default y
1079         help
1080           Disabling this option eliminates support for BUG and WARN, reducing
1081           the size of your kernel image and potentially quietly ignoring
1082           numerous fatal conditions. You should only consider disabling this
1083           option for embedded systems with no facilities for reporting errors.
1084           Just say Y.
1085
1086 config ELF_CORE
1087         default y
1088         bool "Enable ELF core dumps" if EXPERT
1089         help
1090           Enable support for generating core dumps. Disabling saves about 4k.
1091
1092
1093 config PCSPKR_PLATFORM
1094         bool "Enable PC-Speaker support" if EXPERT
1095         depends on HAVE_PCSPKR_PLATFORM
1096         select I8253_LOCK
1097         default y
1098         help
1099           This option allows to disable the internal PC-Speaker
1100           support, saving some memory.
1101
1102 config HAVE_PCSPKR_PLATFORM
1103         bool
1104
1105 config BASE_FULL
1106         default y
1107         bool "Enable full-sized data structures for core" if EXPERT
1108         help
1109           Disabling this option reduces the size of miscellaneous core
1110           kernel data structures. This saves memory on small machines,
1111           but may reduce performance.
1112
1113 config FUTEX
1114         bool "Enable futex support" if EXPERT
1115         default y
1116         select RT_MUTEXES
1117         help
1118           Disabling this option will cause the kernel to be built without
1119           support for "fast userspace mutexes".  The resulting kernel may not
1120           run glibc-based applications correctly.
1121
1122 config EPOLL
1123         bool "Enable eventpoll support" if EXPERT
1124         default y
1125         select ANON_INODES
1126         help
1127           Disabling this option will cause the kernel to be built without
1128           support for epoll family of system calls.
1129
1130 config SIGNALFD
1131         bool "Enable signalfd() system call" if EXPERT
1132         select ANON_INODES
1133         default y
1134         help
1135           Enable the signalfd() system call that allows to receive signals
1136           on a file descriptor.
1137
1138           If unsure, say Y.
1139
1140 config TIMERFD
1141         bool "Enable timerfd() system call" if EXPERT
1142         select ANON_INODES
1143         default y
1144         help
1145           Enable the timerfd() system call that allows to receive timer
1146           events on a file descriptor.
1147
1148           If unsure, say Y.
1149
1150 config EVENTFD
1151         bool "Enable eventfd() system call" if EXPERT
1152         select ANON_INODES
1153         default y
1154         help
1155           Enable the eventfd() system call that allows to receive both
1156           kernel notification (ie. KAIO) or userspace notifications.
1157
1158           If unsure, say Y.
1159
1160 config SHMEM
1161         bool "Use full shmem filesystem" if EXPERT
1162         default y
1163         depends on MMU
1164         help
1165           The shmem is an internal filesystem used to manage shared memory.
1166           It is backed by swap and manages resource limits. It is also exported
1167           to userspace as tmpfs if TMPFS is enabled. Disabling this
1168           option replaces shmem and tmpfs with the much simpler ramfs code,
1169           which may be appropriate on small systems without swap.
1170
1171 config AIO
1172         bool "Enable AIO support" if EXPERT
1173         default y
1174         help
1175           This option enables POSIX asynchronous I/O which may by used
1176           by some high performance threaded applications. Disabling
1177           this option saves about 7k.
1178
1179 config EMBEDDED
1180         bool "Embedded system"
1181         select EXPERT
1182         help
1183           This option should be enabled if compiling the kernel for
1184           an embedded system so certain expert options are available
1185           for configuration.
1186
1187 config HAVE_PERF_EVENTS
1188         bool
1189         help
1190           See tools/perf/design.txt for details.
1191
1192 config PERF_USE_VMALLOC
1193         bool
1194         help
1195           See tools/perf/design.txt for details
1196
1197 menu "Kernel Performance Events And Counters"
1198
1199 config PERF_EVENTS
1200         bool "Kernel performance events and counters"
1201         default y if (PROFILING || PERF_COUNTERS)
1202         depends on HAVE_PERF_EVENTS
1203         select ANON_INODES
1204         select IRQ_WORK
1205         help
1206           Enable kernel support for various performance events provided
1207           by software and hardware.
1208
1209           Software events are supported either built-in or via the
1210           use of generic tracepoints.
1211
1212           Most modern CPUs support performance events via performance
1213           counter registers. These registers count the number of certain
1214           types of hw events: such as instructions executed, cachemisses
1215           suffered, or branches mis-predicted - without slowing down the
1216           kernel or applications. These registers can also trigger interrupts
1217           when a threshold number of events have passed - and can thus be
1218           used to profile the code that runs on that CPU.
1219
1220           The Linux Performance Event subsystem provides an abstraction of
1221           these software and hardware event capabilities, available via a
1222           system call and used by the "perf" utility in tools/perf/. It
1223           provides per task and per CPU counters, and it provides event
1224           capabilities on top of those.
1225
1226           Say Y if unsure.
1227
1228 config PERF_COUNTERS
1229         bool "Kernel performance counters (old config option)"
1230         depends on HAVE_PERF_EVENTS
1231         help
1232           This config has been obsoleted by the PERF_EVENTS
1233           config option - please see that one for details.
1234
1235           It has no effect on the kernel whether you enable
1236           it or not, it is a compatibility placeholder.
1237
1238           Say N if unsure.
1239
1240 config DEBUG_PERF_USE_VMALLOC
1241         default n
1242         bool "Debug: use vmalloc to back perf mmap() buffers"
1243         depends on PERF_EVENTS && DEBUG_KERNEL
1244         select PERF_USE_VMALLOC
1245         help
1246          Use vmalloc memory to back perf mmap() buffers.
1247
1248          Mostly useful for debugging the vmalloc code on platforms
1249          that don't require it.
1250
1251          Say N if unsure.
1252
1253 endmenu
1254
1255 config VM_EVENT_COUNTERS
1256         default y
1257         bool "Enable VM event counters for /proc/vmstat" if EXPERT
1258         help
1259           VM event counters are needed for event counts to be shown.
1260           This option allows the disabling of the VM event counters
1261           on EXPERT systems.  /proc/vmstat will only show page counts
1262           if VM event counters are disabled.
1263
1264 config PCI_QUIRKS
1265         default y
1266         bool "Enable PCI quirk workarounds" if EXPERT
1267         depends on PCI
1268         help
1269           This enables workarounds for various PCI chipset
1270           bugs/quirks. Disable this only if your target machine is
1271           unaffected by PCI quirks.
1272
1273 config SLUB_DEBUG
1274         default y
1275         bool "Enable SLUB debugging support" if EXPERT
1276         depends on SLUB && SYSFS
1277         help
1278           SLUB has extensive debug support features. Disabling these can
1279           result in significant savings in code size. This also disables
1280           SLUB sysfs support. /sys/slab will not exist and there will be
1281           no support for cache validation etc.
1282
1283 config COMPAT_BRK
1284         bool "Disable heap randomization"
1285         default y
1286         help
1287           Randomizing heap placement makes heap exploits harder, but it
1288           also breaks ancient binaries (including anything libc5 based).
1289           This option changes the bootup default to heap randomization
1290           disabled, and can be overridden at runtime by setting
1291           /proc/sys/kernel/randomize_va_space to 2.
1292
1293           On non-ancient distros (post-2000 ones) N is usually a safe choice.
1294
1295 choice
1296         prompt "Choose SLAB allocator"
1297         default SLUB
1298         help
1299            This option allows to select a slab allocator.
1300
1301 config SLAB
1302         bool "SLAB"
1303         help
1304           The regular slab allocator that is established and known to work
1305           well in all environments. It organizes cache hot objects in
1306           per cpu and per node queues.
1307
1308 config SLUB
1309         bool "SLUB (Unqueued Allocator)"
1310         help
1311            SLUB is a slab allocator that minimizes cache line usage
1312            instead of managing queues of cached objects (SLAB approach).
1313            Per cpu caching is realized using slabs of objects instead
1314            of queues of objects. SLUB can use memory efficiently
1315            and has enhanced diagnostics. SLUB is the default choice for
1316            a slab allocator.
1317
1318 config SLOB
1319         depends on EXPERT
1320         bool "SLOB (Simple Allocator)"
1321         help
1322            SLOB replaces the stock allocator with a drastically simpler
1323            allocator. SLOB is generally more space efficient but
1324            does not perform as well on large systems.
1325
1326 endchoice
1327
1328 config MMAP_ALLOW_UNINITIALIZED
1329         bool "Allow mmapped anonymous memory to be uninitialized"
1330         depends on EXPERT && !MMU
1331         default n
1332         help
1333           Normally, and according to the Linux spec, anonymous memory obtained
1334           from mmap() has it's contents cleared before it is passed to
1335           userspace.  Enabling this config option allows you to request that
1336           mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1337           providing a huge performance boost.  If this option is not enabled,
1338           then the flag will be ignored.
1339
1340           This is taken advantage of by uClibc's malloc(), and also by
1341           ELF-FDPIC binfmt's brk and stack allocator.
1342
1343           Because of the obvious security issues, this option should only be
1344           enabled on embedded devices where you control what is run in
1345           userspace.  Since that isn't generally a problem on no-MMU systems,
1346           it is normally safe to say Y here.
1347
1348           See Documentation/nommu-mmap.txt for more information.
1349
1350 config PROFILING
1351         bool "Profiling support"
1352         help
1353           Say Y here to enable the extended profiling support mechanisms used
1354           by profilers such as OProfile.
1355
1356 #
1357 # Place an empty function call at each tracepoint site. Can be
1358 # dynamically changed for a probe function.
1359 #
1360 config TRACEPOINTS
1361         bool
1362
1363 source "arch/Kconfig"
1364
1365 endmenu         # General setup
1366
1367 config HAVE_GENERIC_DMA_COHERENT
1368         bool
1369         default n
1370
1371 config SLABINFO
1372         bool
1373         depends on PROC_FS
1374         depends on SLAB || SLUB_DEBUG
1375         default y
1376
1377 config RT_MUTEXES
1378         boolean
1379
1380 config BASE_SMALL
1381         int
1382         default 0 if BASE_FULL
1383         default 1 if !BASE_FULL
1384
1385 menuconfig MODULES
1386         bool "Enable loadable module support"
1387         help
1388           Kernel modules are small pieces of compiled code which can
1389           be inserted in the running kernel, rather than being
1390           permanently built into the kernel.  You use the "modprobe"
1391           tool to add (and sometimes remove) them.  If you say Y here,
1392           many parts of the kernel can be built as modules (by
1393           answering M instead of Y where indicated): this is most
1394           useful for infrequently used options which are not required
1395           for booting.  For more information, see the man pages for
1396           modprobe, lsmod, modinfo, insmod and rmmod.
1397
1398           If you say Y here, you will need to run "make
1399           modules_install" to put the modules under /lib/modules/
1400           where modprobe can find them (you may need to be root to do
1401           this).
1402
1403           If unsure, say Y.
1404
1405 if MODULES
1406
1407 config MODULE_FORCE_LOAD
1408         bool "Forced module loading"
1409         default n
1410         help
1411           Allow loading of modules without version information (ie. modprobe
1412           --force).  Forced module loading sets the 'F' (forced) taint flag and
1413           is usually a really bad idea.
1414
1415 config MODULE_UNLOAD
1416         bool "Module unloading"
1417         help
1418           Without this option you will not be able to unload any
1419           modules (note that some modules may not be unloadable
1420           anyway), which makes your kernel smaller, faster
1421           and simpler.  If unsure, say Y.
1422
1423 config MODULE_FORCE_UNLOAD
1424         bool "Forced module unloading"
1425         depends on MODULE_UNLOAD && EXPERIMENTAL
1426         help
1427           This option allows you to force a module to unload, even if the
1428           kernel believes it is unsafe: the kernel will remove the module
1429           without waiting for anyone to stop using it (using the -f option to
1430           rmmod).  This is mainly for kernel developers and desperate users.
1431           If unsure, say N.
1432
1433 config MODVERSIONS
1434         bool "Module versioning support"
1435         help
1436           Usually, you have to use modules compiled with your kernel.
1437           Saying Y here makes it sometimes possible to use modules
1438           compiled for different kernels, by adding enough information
1439           to the modules to (hopefully) spot any changes which would
1440           make them incompatible with the kernel you are running.  If
1441           unsure, say N.
1442
1443 config MODULE_SRCVERSION_ALL
1444         bool "Source checksum for all modules"
1445         help
1446           Modules which contain a MODULE_VERSION get an extra "srcversion"
1447           field inserted into their modinfo section, which contains a
1448           sum of the source files which made it.  This helps maintainers
1449           see exactly which source was used to build a module (since
1450           others sometimes change the module source without updating
1451           the version).  With this option, such a "srcversion" field
1452           will be created for all modules.  If unsure, say N.
1453
1454 endif # MODULES
1455
1456 config INIT_ALL_POSSIBLE
1457         bool
1458         help
1459           Back when each arch used to define their own cpu_online_mask and
1460           cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1461           with all 1s, and others with all 0s.  When they were centralised,
1462           it was better to provide this option than to break all the archs
1463           and have several arch maintainers pursuing me down dark alleys.
1464
1465 config STOP_MACHINE
1466         bool
1467         default y
1468         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1469         help
1470           Need stop_machine() primitive.
1471
1472 source "block/Kconfig"
1473
1474 config PREEMPT_NOTIFIERS
1475         bool
1476
1477 config PADATA
1478         depends on SMP
1479         bool
1480
1481 source "kernel/Kconfig.locks"