init/Kconfig

   1 config ARCH
   2         string
   3         option env="ARCH"
   4
   5 config KERNELVERSION
   6         string
   7         option env="KERNELVERSION"
   8
   9 config DEFCONFIG_LIST
  10         string
  11         depends on !UML
  12         option defconfig_list
  13         default "/lib/modules/$UNAME_RELEASE/.config"
  14         default "/etc/kernel-config"
  15         default "/boot/config-$UNAME_RELEASE"
  16         default "$ARCH_DEFCONFIG"
  17         default "arch/$ARCH/defconfig"
  18
  19 config CONSTRUCTORS
  20         bool
  21         depends on !UML
  22         default y
  23
  24 config HAVE_IRQ_WORK
  25         bool
  26
  27 config IRQ_WORK
  28         bool
  29         depends on HAVE_IRQ_WORK
  30
  31 menu "General setup"
  32
  33 config EXPERIMENTAL
  34         bool "Prompt for development and/or incomplete code/drivers"
  35         ---help---
  36           Some of the various things that Linux supports (such as network
  37           drivers, file systems, network protocols, etc.) can be in a state
  38           of development where the functionality, stability, or the level of
  39           testing is not yet high enough for general use. This is usually
  40           known as the "alpha-test" phase among developers. If a feature is
  41           currently in alpha-test, then the developers usually discourage
  42           uninformed widespread use of this feature by the general public to
  43           avoid "Why doesn't this work?" type mail messages. However, active
  44           testing and use of these systems is welcomed. Just be aware that it
  45           may not meet the normal level of reliability or it may fail to work
  46           in some special cases. Detailed bug reports from people familiar
  47           with the kernel internals are usually welcomed by the developers
  48           (before submitting bug reports, please read the documents
  49           <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  50           <file:Documentation/BUG-HUNTING>, and
  51           <file:Documentation/oops-tracing.txt> in the kernel source).
  52
  53           This option will also make obsoleted drivers available. These are
  54           drivers that have been replaced by something else, and/or are
  55           scheduled to be removed in a future kernel release.
  56
  57           Unless you intend to help test and develop a feature or driver that
  58           falls into this category, or you have a situation that requires
  59           using these features, you should probably say N here, which will
  60           cause the configurator to present you with fewer choices. If
  61           you say Y here, you will be offered the choice of using features or
  62           drivers that are currently considered to be in the alpha-test phase.
  63
  64 config BROKEN
  65         bool
  66
  67 config BROKEN_ON_SMP
  68         bool
  69         depends on BROKEN || !SMP
  70         default y
  71
  72 config LOCK_KERNEL
  73         bool
  74         depends on SMP || PREEMPT
  75         default y
  76
  77 config INIT_ENV_ARG_LIMIT
  78         int
  79         default 32 if !UML
  80         default 128 if UML
  81         help
  82           Maximum of each of the number of arguments and environment
  83           variables passed to init from the kernel command line.
  84
  85
  86 config CROSS_COMPILE
  87         string "Cross-compiler tool prefix"
  88         help
  89           Same as running 'make CROSS_COMPILE=prefix-' but stored for
  90           default make runs in this kernel build directory.  You don't
  91           need to set this unless you want the configured kernel build
  92           directory to select the cross-compiler automatically.
  93
  94 config LOCALVERSION
  95         string "Local version - append to kernel release"
  96         help
  97           Append an extra string to the end of your kernel version.
  98           This will show up when you type uname, for example.
  99           The string you set here will be appended after the contents of
 100           any files with a filename matching localversion* in your
 101           object and source tree, in that order.  Your total string can
 102           be a maximum of 64 characters.
 103
 104 config LOCALVERSION_AUTO
 105         bool "Automatically append version information to the version string"
 106         default y
 107         help
 108           This will try to automatically determine if the current tree is a
 109           release tree by looking for git tags that belong to the current
 110           top of tree revision.
 111
 112           A string of the format -gxxxxxxxx will be added to the localversion
 113           if a git-based tree is found.  The string generated by this will be
 114           appended after any matching localversion* files, and after the value
 115           set in CONFIG_LOCALVERSION.
 116
 117           (The actual string used here is the first eight characters produced
 118           by running the command:
 119
 120             $ git rev-parse --verify HEAD
 121
 122           which is done within the script "scripts/setlocalversion".)
 123
 124 config HAVE_KERNEL_GZIP
 125         bool
 126
 127 config HAVE_KERNEL_BZIP2
 128         bool
 129
 130 config HAVE_KERNEL_LZMA
 131         bool
 132
 133 config HAVE_KERNEL_LZO
 134         bool
 135
 136 choice
 137         prompt "Kernel compression mode"
 138         default KERNEL_GZIP
 139         depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
 140         help
 141           The linux kernel is a kind of self-extracting executable.
 142           Several compression algorithms are available, which differ
 143           in efficiency, compression and decompression speed.
 144           Compression speed is only relevant when building a kernel.
 145           Decompression speed is relevant at each boot.
 146
 147           If you have any problems with bzip2 or lzma compressed
 148           kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
 149           version of this functionality (bzip2 only), for 2.4, was
 150           supplied by Christian Ludwig)
 151
 152           High compression options are mostly useful for users, who
 153           are low on disk space (embedded systems), but for whom ram
 154           size matters less.
 155
 156           If in doubt, select 'gzip'
 157
 158 config KERNEL_GZIP
 159         bool "Gzip"
 160         depends on HAVE_KERNEL_GZIP
 161         help
 162           The old and tried gzip compression. It provides a good balance
 163           between compression ratio and decompression speed.
 164
 165 config KERNEL_BZIP2
 166         bool "Bzip2"
 167         depends on HAVE_KERNEL_BZIP2
 168         help
 169           Its compression ratio and speed is intermediate.
 170           Decompression speed is slowest among the three.  The kernel
 171           size is about 10% smaller with bzip2, in comparison to gzip.
 172           Bzip2 uses a large amount of memory. For modern kernels you
 173           will need at least 8MB RAM or more for booting.
 174
 175 config KERNEL_LZMA
 176         bool "LZMA"
 177         depends on HAVE_KERNEL_LZMA
 178         help
 179           The most recent compression algorithm.
 180           Its ratio is best, decompression speed is between the other
 181           two. Compression is slowest.  The kernel size is about 33%
 182           smaller with LZMA in comparison to gzip.
 183
 184 config KERNEL_LZO
 185         bool "LZO"
 186         depends on HAVE_KERNEL_LZO
 187         help
 188           Its compression ratio is the poorest among the 4. The kernel
 189           size is about about 10% bigger than gzip; however its speed
 190           (both compression and decompression) is the fastest.
 191
 192 endchoice
 193
 194 config SWAP
 195         bool "Support for paging of anonymous memory (swap)"
 196         depends on MMU && BLOCK
 197         default y
 198         help
 199           This option allows you to choose whether you want to have support
 200           for so called swap devices or swap files in your kernel that are
 201           used to provide more virtual memory than the actual RAM present
 202           in your computer.  If unsure say Y.
 203
 204 config SYSVIPC
 205         bool "System V IPC"
 206         ---help---
 207           Inter Process Communication is a suite of library functions and
 208           system calls which let processes (running programs) synchronize and
 209           exchange information. It is generally considered to be a good thing,
 210           and some programs won't run unless you say Y here. In particular, if
 211           you want to run the DOS emulator dosemu under Linux (read the
 212           DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 213           you'll need to say Y here.
 214
 215           You can find documentation about IPC with "info ipc" and also in
 216           section 6.4 of the Linux Programmer's Guide, available from
 217           <http://www.tldp.org/guides.html>.
 218
 219 config SYSVIPC_SYSCTL
 220         bool
 221         depends on SYSVIPC
 222         depends on SYSCTL
 223         default y
 224
 225 config POSIX_MQUEUE
 226         bool "POSIX Message Queues"
 227         depends on NET && EXPERIMENTAL
 228         ---help---
 229           POSIX variant of message queues is a part of IPC. In POSIX message
 230           queues every message has a priority which decides about succession
 231           of receiving it by a process. If you want to compile and run
 232           programs written e.g. for Solaris with use of its POSIX message
 233           queues (functions mq_*) say Y here.
 234
 235           POSIX message queues are visible as a filesystem called 'mqueue'
 236           and can be mounted somewhere if you want to do filesystem
 237           operations on message queues.
 238
 239           If unsure, say Y.
 240
 241 config POSIX_MQUEUE_SYSCTL
 242         bool
 243         depends on POSIX_MQUEUE
 244         depends on SYSCTL
 245         default y
 246
 247 config BSD_PROCESS_ACCT
 248         bool "BSD Process Accounting"
 249         help
 250           If you say Y here, a user level program will be able to instruct the
 251           kernel (via a special system call) to write process accounting
 252           information to a file: whenever a process exits, information about
 253           that process will be appended to the file by the kernel.  The
 254           information includes things such as creation time, owning user,
 255           command name, memory usage, controlling terminal etc. (the complete
 256           list is in the struct acct in <file:include/linux/acct.h>).  It is
 257           up to the user level program to do useful things with this
 258           information.  This is generally a good idea, so say Y.
 259
 260 config BSD_PROCESS_ACCT_V3
 261         bool "BSD Process Accounting version 3 file format"
 262         depends on BSD_PROCESS_ACCT
 263         default n
 264         help
 265           If you say Y here, the process accounting information is written
 266           in a new file format that also logs the process IDs of each
 267           process and it's parent. Note that this file format is incompatible
 268           with previous v0/v1/v2 file formats, so you will need updated tools
 269           for processing it. A preliminary version of these tools is available
 270           at <http://www.gnu.org/software/acct/>.
 271
 272 config TASKSTATS
 273         bool "Export task/process statistics through netlink (EXPERIMENTAL)"
 274         depends on NET
 275         default n
 276         help
 277           Export selected statistics for tasks/processes through the
 278           generic netlink interface. Unlike BSD process accounting, the
 279           statistics are available during the lifetime of tasks/processes as
 280           responses to commands. Like BSD accounting, they are sent to user
 281           space on task exit.
 282
 283           Say N if unsure.
 284
 285 config TASK_DELAY_ACCT
 286         bool "Enable per-task delay accounting (EXPERIMENTAL)"
 287         depends on TASKSTATS
 288         help
 289           Collect information on time spent by a task waiting for system
 290           resources like cpu, synchronous block I/O completion and swapping
 291           in pages. Such statistics can help in setting a task's priorities
 292           relative to other tasks for cpu, io, rss limits etc.
 293
 294           Say N if unsure.
 295
 296 config TASK_XACCT
 297         bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
 298         depends on TASKSTATS
 299         help
 300           Collect extended task accounting data and send the data
 301           to userland for processing over the taskstats interface.
 302
 303           Say N if unsure.
 304
 305 config TASK_IO_ACCOUNTING
 306         bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
 307         depends on TASK_XACCT
 308         help
 309           Collect information on the number of bytes of storage I/O which this
 310           task has caused.
 311
 312           Say N if unsure.
 313
 314 config AUDIT
 315         bool "Auditing support"
 316         depends on NET
 317         help
 318           Enable auditing infrastructure that can be used with another
 319           kernel subsystem, such as SELinux (which requires this for
 320           logging of avc messages output).  Does not do system-call
 321           auditing without CONFIG_AUDITSYSCALL.
 322
 323 config AUDITSYSCALL
 324         bool "Enable system-call auditing support"
 325         depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
 326         default y if SECURITY_SELINUX
 327         help
 328           Enable low-overhead system-call auditing infrastructure that
 329           can be used independently or with another kernel subsystem,
 330           such as SELinux.
 331
 332 config AUDIT_WATCH
 333         def_bool y
 334         depends on AUDITSYSCALL
 335         select FSNOTIFY
 336
 337 config AUDIT_TREE
 338         def_bool y
 339         depends on AUDITSYSCALL
 340         select FSNOTIFY
 341
 342 menu "RCU Subsystem"
 343
 344 choice
 345         prompt "RCU Implementation"
 346         default TREE_RCU
 347
 348 config TREE_RCU
 349         bool "Tree-based hierarchical RCU"
 350         depends on !PREEMPT && SMP
 351         help
 352           This option selects the RCU implementation that is
 353           designed for very large SMP system with hundreds or
 354           thousands of CPUs.  It also scales down nicely to
 355           smaller systems.
 356
 357 config TREE_PREEMPT_RCU
 358         bool "Preemptible tree-based hierarchical RCU"
 359         depends on PREEMPT
 360         help
 361           This option selects the RCU implementation that is
 362           designed for very large SMP systems with hundreds or
 363           thousands of CPUs, but for which real-time response
 364           is also required.  It also scales down nicely to
 365           smaller systems.
 366
 367 config TINY_RCU
 368         bool "UP-only small-memory-footprint RCU"
 369         depends on !SMP
 370         help
 371           This option selects the RCU implementation that is
 372           designed for UP systems from which real-time response
 373           is not required.  This option greatly reduces the
 374           memory footprint of RCU.
 375
 376 config TINY_PREEMPT_RCU
 377         bool "Preemptible UP-only small-memory-footprint RCU"
 378         depends on !SMP && PREEMPT
 379         help
 380           This option selects the RCU implementation that is designed
 381           for real-time UP systems.  This option greatly reduces the
 382           memory footprint of RCU.
 383
 384 endchoice
 385
 386 config PREEMPT_RCU
 387         def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
 388         help
 389           This option enables preemptible-RCU code that is common between
 390           the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
 391
 392 config RCU_TRACE
 393         bool "Enable tracing for RCU"
 394         depends on TREE_RCU || TREE_PREEMPT_RCU
 395         help
 396           This option provides tracing in RCU which presents stats
 397           in debugfs for debugging RCU implementation.
 398
 399           Say Y here if you want to enable RCU tracing
 400           Say N if you are unsure.
 401
 402 config RCU_FANOUT
 403         int "Tree-based hierarchical RCU fanout value"
 404         range 2 64 if 64BIT
 405         range 2 32 if !64BIT
 406         depends on TREE_RCU || TREE_PREEMPT_RCU
 407         default 64 if 64BIT
 408         default 32 if !64BIT
 409         help
 410           This option controls the fanout of hierarchical implementations
 411           of RCU, allowing RCU to work efficiently on machines with
 412           large numbers of CPUs.  This value must be at least the fourth
 413           root of NR_CPUS, which allows NR_CPUS to be insanely large.
 414           The default value of RCU_FANOUT should be used for production
 415           systems, but if you are stress-testing the RCU implementation
 416           itself, small RCU_FANOUT values allow you to test large-system
 417           code paths on small(er) systems.
 418
 419           Select a specific number if testing RCU itself.
 420           Take the default if unsure.
 421
 422 config RCU_FANOUT_EXACT
 423         bool "Disable tree-based hierarchical RCU auto-balancing"
 424         depends on TREE_RCU || TREE_PREEMPT_RCU
 425         default n
 426         help
 427           This option forces use of the exact RCU_FANOUT value specified,
 428           regardless of imbalances in the hierarchy.  This is useful for
 429           testing RCU itself, and might one day be useful on systems with
 430           strong NUMA behavior.
 431
 432           Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 433
 434           Say N if unsure.
 435
 436 config RCU_FAST_NO_HZ
 437         bool "Accelerate last non-dyntick-idle CPU's grace periods"
 438         depends on TREE_RCU && NO_HZ && SMP
 439         default n
 440         help
 441           This option causes RCU to attempt to accelerate grace periods
 442           in order to allow the final CPU to enter dynticks-idle state
 443           more quickly.  On the other hand, this option increases the
 444           overhead of the dynticks-idle checking, particularly on systems
 445           with large numbers of CPUs.
 446
 447           Say Y if energy efficiency is critically important, particularly
 448                 if you have relatively few CPUs.
 449
 450           Say N if you are unsure.
 451
 452 config TREE_RCU_TRACE
 453         def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 454         select DEBUG_FS
 455         help
 456           This option provides tracing for the TREE_RCU and
 457           TREE_PREEMPT_RCU implementations, permitting Makefile to
 458           trivially select kernel/rcutree_trace.c.
 459
 460 endmenu # "RCU Subsystem"
 461
 462 config IKCONFIG
 463         tristate "Kernel .config support"
 464         ---help---
 465           This option enables the complete Linux kernel ".config" file
 466           contents to be saved in the kernel. It provides documentation
 467           of which kernel options are used in a running kernel or in an
 468           on-disk kernel.  This information can be extracted from the kernel
 469           image file with the script scripts/extract-ikconfig and used as
 470           input to rebuild the current kernel or to build another kernel.
 471           It can also be extracted from a running kernel by reading
 472           /proc/config.gz if enabled (below).
 473
 474 config IKCONFIG_PROC
 475         bool "Enable access to .config through /proc/config.gz"
 476         depends on IKCONFIG && PROC_FS
 477         ---help---
 478           This option enables access to the kernel configuration file
 479           through /proc/config.gz.
 480
 481 config LOG_BUF_SHIFT
 482         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 483         range 12 21
 484         default 17
 485         help
 486           Select kernel log buffer size as a power of 2.
 487           Examples:
 488                      17 => 128 KB
 489                      16 => 64 KB
 490                      15 => 32 KB
 491                      14 => 16 KB
 492                      13 =>  8 KB
 493                      12 =>  4 KB
 494
 495 #
 496 # Architectures with an unreliable sched_clock() should select this:
 497 #
 498 config HAVE_UNSTABLE_SCHED_CLOCK
 499         bool
 500
 501 menuconfig CGROUPS
 502         boolean "Control Group support"
 503         depends on EVENTFD
 504         help
 505           This option adds support for grouping sets of processes together, for
 506           use with process control subsystems such as Cpusets, CFS, memory
 507           controls or device isolation.
 508           See
 509                 - Documentation/scheduler/sched-design-CFS.txt  (CFS)
 510                 - Documentation/cgroups/ (features for grouping, isolation
 511                                           and resource control)
 512
 513           Say N if unsure.
 514
 515 if CGROUPS
 516
 517 config CGROUP_DEBUG
 518         bool "Example debug cgroup subsystem"
 519         depends on CGROUPS
 520         default n
 521         help
 522           This option enables a simple cgroup subsystem that
 523           exports useful debugging information about the cgroups
 524           framework.
 525
 526           Say N if unsure.
 527
 528 config CGROUP_NS
 529         bool "Namespace cgroup subsystem"
 530         depends on CGROUPS
 531         help
 532           Provides a simple namespace cgroup subsystem to
 533           provide hierarchical naming of sets of namespaces,
 534           for instance virtual servers and checkpoint/restart
 535           jobs.
 536
 537 config CGROUP_FREEZER
 538         bool "Freezer cgroup subsystem"
 539         depends on CGROUPS
 540         help
 541           Provides a way to freeze and unfreeze all tasks in a
 542           cgroup.
 543
 544 config CGROUP_DEVICE
 545         bool "Device controller for cgroups"
 546         depends on CGROUPS && EXPERIMENTAL
 547         help
 548           Provides a cgroup implementing whitelists for devices which
 549           a process in the cgroup can mknod or open.
 550
 551 config CPUSETS
 552         bool "Cpuset support"
 553         depends on CGROUPS
 554         help
 555           This option will let you create and manage CPUSETs which
 556           allow dynamically partitioning a system into sets of CPUs and
 557           Memory Nodes and assigning tasks to run only within those sets.
 558           This is primarily useful on large SMP or NUMA systems.
 559
 560           Say N if unsure.
 561
 562 config PROC_PID_CPUSET
 563         bool "Include legacy /proc/<pid>/cpuset file"
 564         depends on CPUSETS
 565         default y
 566
 567 config CGROUP_CPUACCT
 568         bool "Simple CPU accounting cgroup subsystem"
 569         depends on CGROUPS
 570         help
 571           Provides a simple Resource Controller for monitoring the
 572           total CPU consumed by the tasks in a cgroup.
 573
 574 config RESOURCE_COUNTERS
 575         bool "Resource counters"
 576         help
 577           This option enables controller independent resource accounting
 578           infrastructure that works with cgroups.
 579         depends on CGROUPS
 580
 581 config CGROUP_MEM_RES_CTLR
 582         bool "Memory Resource Controller for Control Groups"
 583         depends on CGROUPS && RESOURCE_COUNTERS
 584         select MM_OWNER
 585         help
 586           Provides a memory resource controller that manages both anonymous
 587           memory and page cache. (See Documentation/cgroups/memory.txt)
 588
 589           Note that setting this option increases fixed memory overhead
 590           associated with each page of memory in the system. By this,
 591           20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 592           usage tracking struct at boot. Total amount of this is printed out
 593           at boot.
 594
 595           Only enable when you're ok with these trade offs and really
 596           sure you need the memory resource controller. Even when you enable
 597           this, you can set "cgroup_disable=memory" at your boot option to
 598           disable memory resource controller and you can avoid overheads.
 599           (and lose benefits of memory resource controller)
 600
 601           This config option also selects MM_OWNER config option, which
 602           could in turn add some fork/exit overhead.
 603
 604 config CGROUP_MEM_RES_CTLR_SWAP
 605         bool "Memory Resource Controller Swap Extension"
 606         depends on CGROUP_MEM_RES_CTLR && SWAP
 607         help
 608           Add swap management feature to memory resource controller. When you
 609           enable this, you can limit mem+swap usage per cgroup. In other words,
 610           when you disable this, memory resource controller has no cares to
 611           usage of swap...a process can exhaust all of the swap. This extension
 612           is useful when you want to avoid exhaustion swap but this itself
 613           adds more overheads and consumes memory for remembering information.
 614           Especially if you use 32bit system or small memory system, please
 615           be careful about enabling this. When memory resource controller
 616           is disabled by boot option, this will be automatically disabled and
 617           there will be no overhead from this. Even when you set this config=y,
 618           if boot option "noswapaccount" is set, swap will not be accounted.
 619           Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 620           size is 4096bytes, 512k per 1Gbytes of swap.
 621
 622 menuconfig CGROUP_SCHED
 623         bool "Group CPU scheduler"
 624         depends on EXPERIMENTAL && CGROUPS
 625         default n
 626         help
 627           This feature lets CPU scheduler recognize task groups and control CPU
 628           bandwidth allocation to such task groups. It uses cgroups to group
 629           tasks.
 630
 631 if CGROUP_SCHED
 632 config FAIR_GROUP_SCHED
 633         bool "Group scheduling for SCHED_OTHER"
 634         depends on CGROUP_SCHED
 635         default CGROUP_SCHED
 636
 637 config RT_GROUP_SCHED
 638         bool "Group scheduling for SCHED_RR/FIFO"
 639         depends on EXPERIMENTAL
 640         depends on CGROUP_SCHED
 641         default n
 642         help
 643           This feature lets you explicitly allocate real CPU bandwidth
 644           to task groups. If enabled, it will also make it impossible to
 645           schedule realtime tasks for non-root users until you allocate
 646           realtime bandwidth for them.
 647           See Documentation/scheduler/sched-rt-group.txt for more information.
 648
 649 endif #CGROUP_SCHED
 650
 651 config BLK_CGROUP
 652         tristate "Block IO controller"
 653         depends on CGROUPS && BLOCK
 654         default n
 655         ---help---
 656         Generic block IO controller cgroup interface. This is the common
 657         cgroup interface which should be used by various IO controlling
 658         policies.
 659
 660         Currently, CFQ IO scheduler uses it to recognize task groups and
 661         control disk bandwidth allocation (proportional time slice allocation)
 662         to such task groups.
 663
 664         This option only enables generic Block IO controller infrastructure.
 665         One needs to also enable actual IO controlling logic in CFQ for it
 666         to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
 667
 668         See Documentation/cgroups/blkio-controller.txt for more information.
 669
 670 config DEBUG_BLK_CGROUP
 671         bool "Enable Block IO controller debugging"
 672         depends on BLK_CGROUP
 673         default n
 674         ---help---
 675         Enable some debugging help. Currently it exports additional stat
 676         files in a cgroup which can be useful for debugging.
 677
 678 endif # CGROUPS
 679
 680 config MM_OWNER
 681         bool
 682
 683 config SYSFS_DEPRECATED
 684         bool
 685
 686 config SYSFS_DEPRECATED_V2
 687         bool "enable deprecated sysfs features to support old userspace tools"
 688         depends on SYSFS
 689         default n
 690         select SYSFS_DEPRECATED
 691         help
 692           This option switches the layout of sysfs to the deprecated
 693           version. Do not use it on recent distributions.
 694
 695           The current sysfs layout features a unified device tree at
 696           /sys/devices/, which is able to express a hierarchy between
 697           class devices. If the deprecated option is set to Y, the
 698           unified device tree is split into a bus device tree at
 699           /sys/devices/ and several individual class device trees at
 700           /sys/class/. The class and bus devices will be connected by
 701           "<subsystem>:<name>" and the "device" links. The "block"
 702           class devices, will not show up in /sys/class/block/. Some
 703           subsystems will suppress the creation of some devices which
 704           depend on the unified device tree.
 705
 706           This option is not a pure compatibility option that can
 707           be safely enabled on newer distributions. It will change the
 708           layout of sysfs to the non-extensible deprecated version,
 709           and disable some features, which can not be exported without
 710           confusing older userspace tools. Since 2007/2008 all major
 711           distributions do not enable this option, and ship no tools which
 712           depend on the deprecated layout or this option.
 713
 714           If you are using a new kernel on an older distribution, or use
 715           older userspace tools, you might need to say Y here. Do not say Y,
 716           if the original kernel, that came with your distribution, has
 717           this option set to N.
 718
 719 config RELAY
 720         bool "Kernel->user space relay support (formerly relayfs)"
 721         help
 722           This option enables support for relay interface support in
 723           certain file systems (such as debugfs).
 724           It is designed to provide an efficient mechanism for tools and
 725           facilities to relay large amounts of data from kernel space to
 726           user space.
 727
 728           If unsure, say N.
 729
 730 config NAMESPACES
 731         bool "Namespaces support" if EMBEDDED
 732         default !EMBEDDED
 733         help
 734           Provides the way to make tasks work with different objects using
 735           the same id. For example same IPC id may refer to different objects
 736           or same user id or pid may refer to different tasks when used in
 737           different namespaces.
 738
 739 config UTS_NS
 740         bool "UTS namespace"
 741         depends on NAMESPACES
 742         help
 743           In this namespace tasks see different info provided with the
 744           uname() system call
 745
 746 config IPC_NS
 747         bool "IPC namespace"
 748         depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
 749         help
 750           In this namespace tasks work with IPC ids which correspond to
 751           different IPC objects in different namespaces.
 752
 753 config USER_NS
 754         bool "User namespace (EXPERIMENTAL)"
 755         depends on NAMESPACES && EXPERIMENTAL
 756         help
 757           This allows containers, i.e. vservers, to use user namespaces
 758           to provide different user info for different servers.
 759           If unsure, say N.
 760
 761 config PID_NS
 762         bool "PID Namespaces (EXPERIMENTAL)"
 763         default n
 764         depends on NAMESPACES && EXPERIMENTAL
 765         help
 766           Support process id namespaces.  This allows having multiple
 767           processes with the same pid as long as they are in different
 768           pid namespaces.  This is a building block of containers.
 769
 770           Unless you want to work with an experimental feature
 771           say N here.
 772
 773 config NET_NS
 774         bool "Network namespace"
 775         default n
 776         depends on NAMESPACES && EXPERIMENTAL && NET
 777         help
 778           Allow user space to create what appear to be multiple instances
 779           of the network stack.
 780
 781 config BLK_DEV_INITRD
 782         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 783         depends on BROKEN || !FRV
 784         help
 785           The initial RAM filesystem is a ramfs which is loaded by the
 786           boot loader (loadlin or lilo) and that is mounted as root
 787           before the normal boot procedure. It is typically used to
 788           load modules needed to mount the "real" root file system,
 789           etc. See <file:Documentation/initrd.txt> for details.
 790
 791           If RAM disk support (BLK_DEV_RAM) is also included, this
 792           also enables initial RAM disk (initrd) support and adds
 793           15 Kbytes (more on some other architectures) to the kernel size.
 794
 795           If unsure say Y.
 796
 797 if BLK_DEV_INITRD
 798
 799 source "usr/Kconfig"
 800
 801 endif
 802
 803 config CC_OPTIMIZE_FOR_SIZE
 804         bool "Optimize for size"
 805         default y
 806         help
 807           Enabling this option will pass "-Os" instead of "-O2" to gcc
 808           resulting in a smaller kernel.
 809
 810           If unsure, say Y.
 811
 812 config SYSCTL
 813         bool
 814
 815 config ANON_INODES
 816         bool
 817
 818 menuconfig EMBEDDED
 819         bool "Configure standard kernel features (for small systems)"
 820         help
 821           This option allows certain base kernel options and settings
 822           to be disabled or tweaked. This is for specialized
 823           environments which can tolerate a "non-standard" kernel.
 824           Only use this if you really know what you are doing.
 825
 826 config UID16
 827         bool "Enable 16-bit UID system calls" if EMBEDDED
 828         depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 829         default y
 830         help
 831           This enables the legacy 16-bit UID syscall wrappers.
 832
 833 config SYSCTL_SYSCALL
 834         bool "Sysctl syscall support" if EMBEDDED
 835         depends on PROC_SYSCTL
 836         default y
 837         select SYSCTL
 838         ---help---
 839           sys_sysctl uses binary paths that have been found challenging
 840           to properly maintain and use.  The interface in /proc/sys
 841           using paths with ascii names is now the primary path to this
 842           information.
 843
 844           Almost nothing using the binary sysctl interface so if you are
 845           trying to save some space it is probably safe to disable this,
 846           making your kernel marginally smaller.
 847
 848           If unsure say Y here.
 849
 850 config KALLSYMS
 851          bool "Load all symbols for debugging/ksymoops" if EMBEDDED
 852          default y
 853          help
 854            Say Y here to let the kernel print out symbolic crash information and
 855            symbolic stack backtraces. This increases the size of the kernel
 856            somewhat, as all symbols have to be loaded into the kernel image.
 857
 858 config KALLSYMS_ALL
 859         bool "Include all symbols in kallsyms"
 860         depends on DEBUG_KERNEL && KALLSYMS
 861         help
 862            Normally kallsyms only contains the symbols of functions, for nicer
 863            OOPS messages.  Some debuggers can use kallsyms for other
 864            symbols too: say Y here to include all symbols, if you need them
 865            and you don't care about adding 300k to the size of your kernel.
 866
 867            Say N.
 868
 869 config KALLSYMS_EXTRA_PASS
 870         bool "Do an extra kallsyms pass"
 871         depends on KALLSYMS
 872         help
 873            If kallsyms is not working correctly, the build will fail with
 874            inconsistent kallsyms data.  If that occurs, log a bug report and
 875            turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
 876            Always say N here unless you find a bug in kallsyms, which must be
 877            reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 878            you wait for kallsyms to be fixed.
 879
 880
 881 config HOTPLUG
 882         bool "Support for hot-pluggable devices" if EMBEDDED
 883         default y
 884         help
 885           This option is provided for the case where no hotplug or uevent
 886           capabilities is wanted by the kernel.  You should only consider
 887           disabling this option for embedded systems that do not use modules, a
 888           dynamic /dev tree, or dynamic device discovery.  Just say Y.
 889
 890 config PRINTK
 891         default y
 892         bool "Enable support for printk" if EMBEDDED
 893         help
 894           This option enables normal printk support. Removing it
 895           eliminates most of the message strings from the kernel image
 896           and makes the kernel more or less silent. As this makes it
 897           very difficult to diagnose system problems, saying N here is
 898           strongly discouraged.
 899
 900 config BUG
 901         bool "BUG() support" if EMBEDDED
 902         default y
 903         help
 904           Disabling this option eliminates support for BUG and WARN, reducing
 905           the size of your kernel image and potentially quietly ignoring
 906           numerous fatal conditions. You should only consider disabling this
 907           option for embedded systems with no facilities for reporting errors.
 908           Just say Y.
 909
 910 config ELF_CORE
 911         default y
 912         bool "Enable ELF core dumps" if EMBEDDED
 913         help
 914           Enable support for generating core dumps. Disabling saves about 4k.
 915
 916 config PCSPKR_PLATFORM
 917         bool "Enable PC-Speaker support" if EMBEDDED
 918         depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
 919         default y
 920         help
 921           This option allows to disable the internal PC-Speaker
 922           support, saving some memory.
 923
 924 config BASE_FULL
 925         default y
 926         bool "Enable full-sized data structures for core" if EMBEDDED
 927         help
 928           Disabling this option reduces the size of miscellaneous core
 929           kernel data structures. This saves memory on small machines,
 930           but may reduce performance.
 931
 932 config FUTEX
 933         bool "Enable futex support" if EMBEDDED
 934         default y
 935         select RT_MUTEXES
 936         help
 937           Disabling this option will cause the kernel to be built without
 938           support for "fast userspace mutexes".  The resulting kernel may not
 939           run glibc-based applications correctly.
 940
 941 config EPOLL
 942         bool "Enable eventpoll support" if EMBEDDED
 943         default y
 944         select ANON_INODES
 945         help
 946           Disabling this option will cause the kernel to be built without
 947           support for epoll family of system calls.
 948
 949 config SIGNALFD
 950         bool "Enable signalfd() system call" if EMBEDDED
 951         select ANON_INODES
 952         default y
 953         help
 954           Enable the signalfd() system call that allows to receive signals
 955           on a file descriptor.
 956
 957           If unsure, say Y.
 958
 959 config TIMERFD
 960         bool "Enable timerfd() system call" if EMBEDDED
 961         select ANON_INODES
 962         default y
 963         help
 964           Enable the timerfd() system call that allows to receive timer
 965           events on a file descriptor.
 966
 967           If unsure, say Y.
 968
 969 config EVENTFD
 970         bool "Enable eventfd() system call" if EMBEDDED
 971         select ANON_INODES
 972         default y
 973         help
 974           Enable the eventfd() system call that allows to receive both
 975           kernel notification (ie. KAIO) or userspace notifications.
 976
 977           If unsure, say Y.
 978
 979 config SHMEM
 980         bool "Use full shmem filesystem" if EMBEDDED
 981         default y
 982         depends on MMU
 983         help
 984           The shmem is an internal filesystem used to manage shared memory.
 985           It is backed by swap and manages resource limits. It is also exported
 986           to userspace as tmpfs if TMPFS is enabled. Disabling this
 987           option replaces shmem and tmpfs with the much simpler ramfs code,
 988           which may be appropriate on small systems without swap.
 989
 990 config AIO
 991         bool "Enable AIO support" if EMBEDDED
 992         default y
 993         help
 994           This option enables POSIX asynchronous I/O which may by used
 995           by some high performance threaded applications. Disabling
 996           this option saves about 7k.
 997
 998 config HAVE_PERF_EVENTS
 999         bool
1000         help
1001           See tools/perf/design.txt for details.
1002
1003 config PERF_USE_VMALLOC
1004         bool
1005         help
1006           See tools/perf/design.txt for details
1007
1008 menu "Kernel Performance Events And Counters"
1009
1010 config PERF_EVENTS
1011         bool "Kernel performance events and counters"
1012         default y if (PROFILING || PERF_COUNTERS)
1013         depends on HAVE_PERF_EVENTS
1014         select ANON_INODES
1015         select IRQ_WORK
1016         help
1017           Enable kernel support for various performance events provided
1018           by software and hardware.
1019
1020           Software events are supported either built-in or via the
1021           use of generic tracepoints.
1022
1023           Most modern CPUs support performance events via performance
1024           counter registers. These registers count the number of certain
1025           types of hw events: such as instructions executed, cachemisses
1026           suffered, or branches mis-predicted - without slowing down the
1027           kernel or applications. These registers can also trigger interrupts
1028           when a threshold number of events have passed - and can thus be
1029           used to profile the code that runs on that CPU.
1030
1031           The Linux Performance Event subsystem provides an abstraction of
1032           these software and hardware event capabilities, available via a
1033           system call and used by the "perf" utility in tools/perf/. It
1034           provides per task and per CPU counters, and it provides event
1035           capabilities on top of those.
1036
1037           Say Y if unsure.
1038
1039 config PERF_COUNTERS
1040         bool "Kernel performance counters (old config option)"
1041         depends on HAVE_PERF_EVENTS
1042         help
1043           This config has been obsoleted by the PERF_EVENTS
1044           config option - please see that one for details.
1045
1046           It has no effect on the kernel whether you enable
1047           it or not, it is a compatibility placeholder.
1048
1049           Say N if unsure.
1050
1051 config DEBUG_PERF_USE_VMALLOC
1052         default n
1053         bool "Debug: use vmalloc to back perf mmap() buffers"
1054         depends on PERF_EVENTS && DEBUG_KERNEL
1055         select PERF_USE_VMALLOC
1056         help
1057          Use vmalloc memory to back perf mmap() buffers.
1058
1059          Mostly useful for debugging the vmalloc code on platforms
1060          that don't require it.
1061
1062          Say N if unsure.
1063
1064 endmenu
1065
1066 config VM_EVENT_COUNTERS
1067         default y
1068         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
1069         help
1070           VM event counters are needed for event counts to be shown.
1071           This option allows the disabling of the VM event counters
1072           on EMBEDDED systems.  /proc/vmstat will only show page counts
1073           if VM event counters are disabled.
1074
1075 config PCI_QUIRKS
1076         default y
1077         bool "Enable PCI quirk workarounds" if EMBEDDED
1078         depends on PCI
1079         help
1080           This enables workarounds for various PCI chipset
1081           bugs/quirks. Disable this only if your target machine is
1082           unaffected by PCI quirks.
1083
1084 config SLUB_DEBUG
1085         default y
1086         bool "Enable SLUB debugging support" if EMBEDDED
1087         depends on SLUB && SYSFS
1088         help
1089           SLUB has extensive debug support features. Disabling these can
1090           result in significant savings in code size. This also disables
1091           SLUB sysfs support. /sys/slab will not exist and there will be
1092           no support for cache validation etc.
1093
1094 config COMPAT_BRK
1095         bool "Disable heap randomization"
1096         default y
1097         help
1098           Randomizing heap placement makes heap exploits harder, but it
1099           also breaks ancient binaries (including anything libc5 based).
1100           This option changes the bootup default to heap randomization
1101           disabled, and can be overridden at runtime by setting
1102           /proc/sys/kernel/randomize_va_space to 2.
1103
1104           On non-ancient distros (post-2000 ones) N is usually a safe choice.
1105
1106 choice
1107         prompt "Choose SLAB allocator"
1108         default SLUB
1109         help
1110            This option allows to select a slab allocator.
1111
1112 config SLAB
1113         bool "SLAB"
1114         help
1115           The regular slab allocator that is established and known to work
1116           well in all environments. It organizes cache hot objects in
1117           per cpu and per node queues.
1118
1119 config SLUB
1120         bool "SLUB (Unqueued Allocator)"
1121         help
1122            SLUB is a slab allocator that minimizes cache line usage
1123            instead of managing queues of cached objects (SLAB approach).
1124            Per cpu caching is realized using slabs of objects instead
1125            of queues of objects. SLUB can use memory efficiently
1126            and has enhanced diagnostics. SLUB is the default choice for
1127            a slab allocator.
1128
1129 config SLOB
1130         depends on EMBEDDED
1131         bool "SLOB (Simple Allocator)"
1132         help
1133            SLOB replaces the stock allocator with a drastically simpler
1134            allocator. SLOB is generally more space efficient but
1135            does not perform as well on large systems.
1136
1137 endchoice
1138
1139 config MMAP_ALLOW_UNINITIALIZED
1140         bool "Allow mmapped anonymous memory to be uninitialized"
1141         depends on EMBEDDED && !MMU
1142         default n
1143         help
1144           Normally, and according to the Linux spec, anonymous memory obtained
1145           from mmap() has it's contents cleared before it is passed to
1146           userspace.  Enabling this config option allows you to request that
1147           mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1148           providing a huge performance boost.  If this option is not enabled,
1149           then the flag will be ignored.
1150
1151           This is taken advantage of by uClibc's malloc(), and also by
1152           ELF-FDPIC binfmt's brk and stack allocator.
1153
1154           Because of the obvious security issues, this option should only be
1155           enabled on embedded devices where you control what is run in
1156           userspace.  Since that isn't generally a problem on no-MMU systems,
1157           it is normally safe to say Y here.
1158
1159           See Documentation/nommu-mmap.txt for more information.
1160
1161 config PROFILING
1162         bool "Profiling support"
1163         help
1164           Say Y here to enable the extended profiling support mechanisms used
1165           by profilers such as OProfile.
1166
1167 #
1168 # Place an empty function call at each tracepoint site. Can be
1169 # dynamically changed for a probe function.
1170 #
1171 config TRACEPOINTS
1172         bool
1173
1174 source "arch/Kconfig"
1175
1176 endmenu         # General setup
1177
1178 config HAVE_GENERIC_DMA_COHERENT
1179         bool
1180         default n
1181
1182 config SLABINFO
1183         bool
1184         depends on PROC_FS
1185         depends on SLAB || SLUB_DEBUG
1186         default y
1187
1188 config RT_MUTEXES
1189         boolean
1190
1191 config BASE_SMALL
1192         int
1193         default 0 if BASE_FULL
1194         default 1 if !BASE_FULL
1195
1196 menuconfig MODULES
1197         bool "Enable loadable module support"
1198         help
1199           Kernel modules are small pieces of compiled code which can
1200           be inserted in the running kernel, rather than being
1201           permanently built into the kernel.  You use the "modprobe"
1202           tool to add (and sometimes remove) them.  If you say Y here,
1203           many parts of the kernel can be built as modules (by
1204           answering M instead of Y where indicated): this is most
1205           useful for infrequently used options which are not required
1206           for booting.  For more information, see the man pages for
1207           modprobe, lsmod, modinfo, insmod and rmmod.
1208
1209           If you say Y here, you will need to run "make
1210           modules_install" to put the modules under /lib/modules/
1211           where modprobe can find them (you may need to be root to do
1212           this).
1213
1214           If unsure, say Y.
1215
1216 if MODULES
1217
1218 config MODULE_FORCE_LOAD
1219         bool "Forced module loading"
1220         default n
1221         help
1222           Allow loading of modules without version information (ie. modprobe
1223           --force).  Forced module loading sets the 'F' (forced) taint flag and
1224           is usually a really bad idea.
1225
1226 config MODULE_UNLOAD
1227         bool "Module unloading"
1228         help
1229           Without this option you will not be able to unload any
1230           modules (note that some modules may not be unloadable
1231           anyway), which makes your kernel smaller, faster
1232           and simpler.  If unsure, say Y.
1233
1234 config MODULE_FORCE_UNLOAD
1235         bool "Forced module unloading"
1236         depends on MODULE_UNLOAD && EXPERIMENTAL
1237         help
1238           This option allows you to force a module to unload, even if the
1239           kernel believes it is unsafe: the kernel will remove the module
1240           without waiting for anyone to stop using it (using the -f option to
1241           rmmod).  This is mainly for kernel developers and desperate users.
1242           If unsure, say N.
1243
1244 config MODVERSIONS
1245         bool "Module versioning support"
1246         help
1247           Usually, you have to use modules compiled with your kernel.
1248           Saying Y here makes it sometimes possible to use modules
1249           compiled for different kernels, by adding enough information
1250           to the modules to (hopefully) spot any changes which would
1251           make them incompatible with the kernel you are running.  If
1252           unsure, say N.
1253
1254 config MODULE_SRCVERSION_ALL
1255         bool "Source checksum for all modules"
1256         help
1257           Modules which contain a MODULE_VERSION get an extra "srcversion"
1258           field inserted into their modinfo section, which contains a
1259           sum of the source files which made it.  This helps maintainers
1260           see exactly which source was used to build a module (since
1261           others sometimes change the module source without updating
1262           the version).  With this option, such a "srcversion" field
1263           will be created for all modules.  If unsure, say N.
1264
1265 endif # MODULES
1266
1267 config INIT_ALL_POSSIBLE
1268         bool
1269         help
1270           Back when each arch used to define their own cpu_online_map and
1271           cpu_possible_map, some of them chose to initialize cpu_possible_map
1272           with all 1s, and others with all 0s.  When they were centralised,
1273           it was better to provide this option than to break all the archs
1274           and have several arch maintainers pursuing me down dark alleys.
1275
1276 config STOP_MACHINE
1277         bool
1278         default y
1279         depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1280         help
1281           Need stop_machine() primitive.
1282
1283 source "block/Kconfig"
1284
1285 config PREEMPT_NOTIFIERS
1286         bool
1287
1288 config PADATA
1289         depends on SMP
1290         bool
1291
1292 source "kernel/Kconfig.locks"