1config ARCH
   2	string
   3	option env="ARCH"
   4
   5config KERNELVERSION
   6	string
   7	option env="KERNELVERSION"
   8
   9config 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
  19config CONSTRUCTORS
  20	bool
  21	depends on !UML
  22
  23config HAVE_IRQ_WORK
  24	bool
  25
  26config IRQ_WORK
  27	bool
  28	depends on HAVE_IRQ_WORK
  29
  30menu "General setup"
  31
  32config 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  53	  drivers that have been replaced by something else, and/or are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
  63config BROKEN
  64	bool
  65
  66config BROKEN_ON_SMP
  67	bool
  68	depends on BROKEN || !SMP
  69	default y
  70
  71config 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
  80config 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
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  88config 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
  98config 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
 118config HAVE_KERNEL_GZIP
 119	bool
 120
 121config HAVE_KERNEL_BZIP2
 122	bool
 123
 124config HAVE_KERNEL_LZMA
 125	bool
 126
 127config HAVE_KERNEL_XZ
 128	bool
 129
 130config HAVE_KERNEL_LZO
 131	bool
 132
 
 
 
 133choice
 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
 155config 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
 162config 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
 172config 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
 181config 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
 196config 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
 
 
 
 
 
 
 
 
 
 
 
 
 204endchoice
 205
 206config 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
 215config 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
 225config 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
 240config SYSVIPC_SYSCTL
 241	bool
 242	depends on SYSVIPC
 243	depends on SYSCTL
 244	default y
 245
 246config 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
 262config POSIX_MQUEUE_SYSCTL
 263	bool
 264	depends on POSIX_MQUEUE
 265	depends on SYSCTL
 266	default y
 267
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 268config 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
 281config 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
 293config 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
 305config 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
 318config 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
 329config 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
 338config 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
 347config 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
 356config AUDITSYSCALL
 357	bool "Enable system-call auditing support"
 358	depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
 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
 365config AUDIT_WATCH
 366	def_bool y
 367	depends on AUDITSYSCALL
 368	select FSNOTIFY
 369
 370config AUDIT_TREE
 371	def_bool y
 372	depends on AUDITSYSCALL
 373	select FSNOTIFY
 374
 375source "kernel/irq/Kconfig"
 376
 377menu "RCU Subsystem"
 378
 379choice
 380	prompt "RCU Implementation"
 381	default TREE_RCU
 382
 383config TREE_RCU
 384	bool "Tree-based hierarchical RCU"
 385	depends on !PREEMPT && SMP
 
 386	help
 387	  This option selects the RCU implementation that is
 388	  designed for very large SMP system with hundreds or
 389	  thousands of CPUs.  It also scales down nicely to
 390	  smaller systems.
 391
 392config TREE_PREEMPT_RCU
 393	bool "Preemptible tree-based hierarchical RCU"
 394	depends on PREEMPT
 
 395	help
 396	  This option selects the RCU implementation that is
 397	  designed for very large SMP systems with hundreds or
 398	  thousands of CPUs, but for which real-time response
 399	  is also required.  It also scales down nicely to
 400	  smaller systems.
 401
 
 
 402config TINY_RCU
 403	bool "UP-only small-memory-footprint RCU"
 404	depends on !SMP
 405	help
 406	  This option selects the RCU implementation that is
 407	  designed for UP systems from which real-time response
 408	  is not required.  This option greatly reduces the
 409	  memory footprint of RCU.
 410
 411config TINY_PREEMPT_RCU
 412	bool "Preemptible UP-only small-memory-footprint RCU"
 413	depends on !SMP && PREEMPT
 414	help
 415	  This option selects the RCU implementation that is designed
 416	  for real-time UP systems.  This option greatly reduces the
 417	  memory footprint of RCU.
 418
 419endchoice
 420
 421config PREEMPT_RCU
 422	def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
 423	help
 424	  This option enables preemptible-RCU code that is common between
 425	  the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
 426
 427config RCU_TRACE
 428	bool "Enable tracing for RCU"
 429	help
 430	  This option provides tracing in RCU which presents stats
 431	  in debugfs for debugging RCU implementation.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 432
 433	  Say Y here if you want to enable RCU tracing
 434	  Say N if you are unsure.
 435
 436config RCU_FANOUT
 437	int "Tree-based hierarchical RCU fanout value"
 438	range 2 64 if 64BIT
 439	range 2 32 if !64BIT
 440	depends on TREE_RCU || TREE_PREEMPT_RCU
 441	default 64 if 64BIT
 442	default 32 if !64BIT
 443	help
 444	  This option controls the fanout of hierarchical implementations
 445	  of RCU, allowing RCU to work efficiently on machines with
 446	  large numbers of CPUs.  This value must be at least the fourth
 447	  root of NR_CPUS, which allows NR_CPUS to be insanely large.
 448	  The default value of RCU_FANOUT should be used for production
 449	  systems, but if you are stress-testing the RCU implementation
 450	  itself, small RCU_FANOUT values allow you to test large-system
 451	  code paths on small(er) systems.
 452
 453	  Select a specific number if testing RCU itself.
 454	  Take the default if unsure.
 455
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 456config RCU_FANOUT_EXACT
 457	bool "Disable tree-based hierarchical RCU auto-balancing"
 458	depends on TREE_RCU || TREE_PREEMPT_RCU
 459	default n
 460	help
 461	  This option forces use of the exact RCU_FANOUT value specified,
 462	  regardless of imbalances in the hierarchy.  This is useful for
 463	  testing RCU itself, and might one day be useful on systems with
 464	  strong NUMA behavior.
 465
 466	  Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 467
 468	  Say N if unsure.
 469
 470config RCU_FAST_NO_HZ
 471	bool "Accelerate last non-dyntick-idle CPU's grace periods"
 472	depends on TREE_RCU && NO_HZ && SMP
 473	default n
 474	help
 475	  This option causes RCU to attempt to accelerate grace periods
 476	  in order to allow the final CPU to enter dynticks-idle state
 477	  more quickly.  On the other hand, this option increases the
 478	  overhead of the dynticks-idle checking, particularly on systems
 479	  with large numbers of CPUs.
 
 
 480
 481	  Say Y if energy efficiency is critically important, particularly
 482	  	if you have relatively few CPUs.
 483
 484	  Say N if you are unsure.
 485
 486config TREE_RCU_TRACE
 487	def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 488	select DEBUG_FS
 489	help
 490	  This option provides tracing for the TREE_RCU and
 491	  TREE_PREEMPT_RCU implementations, permitting Makefile to
 492	  trivially select kernel/rcutree_trace.c.
 493
 494config RCU_BOOST
 495	bool "Enable RCU priority boosting"
 496	depends on RT_MUTEXES && PREEMPT_RCU
 497	default n
 498	help
 499	  This option boosts the priority of preempted RCU readers that
 500	  block the current preemptible RCU grace period for too long.
 501	  This option also prevents heavy loads from blocking RCU
 502	  callback invocation for all flavors of RCU.
 503
 504	  Say Y here if you are working with real-time apps or heavy loads
 505	  Say N here if you are unsure.
 506
 507config RCU_BOOST_PRIO
 508	int "Real-time priority to boost RCU readers to"
 509	range 1 99
 510	depends on RCU_BOOST
 511	default 1
 512	help
 513	  This option specifies the real-time priority to which preempted
 514	  RCU readers are to be boosted.  If you are working with CPU-bound
 515	  real-time applications, you should specify a priority higher then
 516	  the highest-priority CPU-bound application.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 517
 518	  Specify the real-time priority, or take the default if unsure.
 519
 520config RCU_BOOST_DELAY
 521	int "Milliseconds to delay boosting after RCU grace-period start"
 522	range 0 3000
 523	depends on RCU_BOOST
 524	default 500
 525	help
 526	  This option specifies the time to wait after the beginning of
 527	  a given grace period before priority-boosting preempted RCU
 528	  readers blocking that grace period.  Note that any RCU reader
 529	  blocking an expedited RCU grace period is boosted immediately.
 530
 531	  Accept the default if unsure.
 532
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 533endmenu # "RCU Subsystem"
 534
 535config IKCONFIG
 536	tristate "Kernel .config support"
 537	---help---
 538	  This option enables the complete Linux kernel ".config" file
 539	  contents to be saved in the kernel. It provides documentation
 540	  of which kernel options are used in a running kernel or in an
 541	  on-disk kernel.  This information can be extracted from the kernel
 542	  image file with the script scripts/extract-ikconfig and used as
 543	  input to rebuild the current kernel or to build another kernel.
 544	  It can also be extracted from a running kernel by reading
 545	  /proc/config.gz if enabled (below).
 546
 547config IKCONFIG_PROC
 548	bool "Enable access to .config through /proc/config.gz"
 549	depends on IKCONFIG && PROC_FS
 550	---help---
 551	  This option enables access to the kernel configuration file
 552	  through /proc/config.gz.
 553
 554config LOG_BUF_SHIFT
 555	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 556	range 12 21
 557	default 17
 558	help
 559	  Select kernel log buffer size as a power of 2.
 560	  Examples:
 561	  	     17 => 128 KB
 562		     16 => 64 KB
 563	             15 => 32 KB
 564	             14 => 16 KB
 565		     13 =>  8 KB
 566		     12 =>  4 KB
 567
 568#
 569# Architectures with an unreliable sched_clock() should select this:
 570#
 571config HAVE_UNSTABLE_SCHED_CLOCK
 572	bool
 573
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 574menuconfig CGROUPS
 575	boolean "Control Group support"
 576	depends on EVENTFD
 577	help
 578	  This option adds support for grouping sets of processes together, for
 579	  use with process control subsystems such as Cpusets, CFS, memory
 580	  controls or device isolation.
 581	  See
 582		- Documentation/scheduler/sched-design-CFS.txt	(CFS)
 583		- Documentation/cgroups/ (features for grouping, isolation
 584					  and resource control)
 585
 586	  Say N if unsure.
 587
 588if CGROUPS
 589
 590config CGROUP_DEBUG
 591	bool "Example debug cgroup subsystem"
 592	default n
 593	help
 594	  This option enables a simple cgroup subsystem that
 595	  exports useful debugging information about the cgroups
 596	  framework.
 597
 598	  Say N if unsure.
 599
 600config CGROUP_FREEZER
 601	bool "Freezer cgroup subsystem"
 602	help
 603	  Provides a way to freeze and unfreeze all tasks in a
 604	  cgroup.
 605
 606config CGROUP_DEVICE
 607	bool "Device controller for cgroups"
 608	help
 609	  Provides a cgroup implementing whitelists for devices which
 610	  a process in the cgroup can mknod or open.
 611
 612config CPUSETS
 613	bool "Cpuset support"
 614	help
 615	  This option will let you create and manage CPUSETs which
 616	  allow dynamically partitioning a system into sets of CPUs and
 617	  Memory Nodes and assigning tasks to run only within those sets.
 618	  This is primarily useful on large SMP or NUMA systems.
 619
 620	  Say N if unsure.
 621
 622config PROC_PID_CPUSET
 623	bool "Include legacy /proc/<pid>/cpuset file"
 624	depends on CPUSETS
 625	default y
 626
 627config CGROUP_CPUACCT
 628	bool "Simple CPU accounting cgroup subsystem"
 629	help
 630	  Provides a simple Resource Controller for monitoring the
 631	  total CPU consumed by the tasks in a cgroup.
 632
 633config RESOURCE_COUNTERS
 634	bool "Resource counters"
 635	help
 636	  This option enables controller independent resource accounting
 637	  infrastructure that works with cgroups.
 638
 639config CGROUP_MEM_RES_CTLR
 640	bool "Memory Resource Controller for Control Groups"
 641	depends on RESOURCE_COUNTERS
 642	select MM_OWNER
 
 643	help
 644	  Provides a memory resource controller that manages both anonymous
 645	  memory and page cache. (See Documentation/cgroups/memory.txt)
 646
 647	  Note that setting this option increases fixed memory overhead
 648	  associated with each page of memory in the system. By this,
 649	  20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 650	  usage tracking struct at boot. Total amount of this is printed out
 651	  at boot.
 652
 653	  Only enable when you're ok with these trade offs and really
 654	  sure you need the memory resource controller. Even when you enable
 655	  this, you can set "cgroup_disable=memory" at your boot option to
 656	  disable memory resource controller and you can avoid overheads.
 657	  (and lose benefits of memory resource controller)
 658
 659	  This config option also selects MM_OWNER config option, which
 660	  could in turn add some fork/exit overhead.
 661
 662config CGROUP_MEM_RES_CTLR_SWAP
 663	bool "Memory Resource Controller Swap Extension"
 664	depends on CGROUP_MEM_RES_CTLR && SWAP
 665	help
 666	  Add swap management feature to memory resource controller. When you
 667	  enable this, you can limit mem+swap usage per cgroup. In other words,
 668	  when you disable this, memory resource controller has no cares to
 669	  usage of swap...a process can exhaust all of the swap. This extension
 670	  is useful when you want to avoid exhaustion swap but this itself
 671	  adds more overheads and consumes memory for remembering information.
 672	  Especially if you use 32bit system or small memory system, please
 673	  be careful about enabling this. When memory resource controller
 674	  is disabled by boot option, this will be automatically disabled and
 675	  there will be no overhead from this. Even when you set this config=y,
 676	  if boot option "swapaccount=0" is set, swap will not be accounted.
 677	  Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 678	  size is 4096bytes, 512k per 1Gbytes of swap.
 679config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
 680	bool "Memory Resource Controller Swap Extension enabled by default"
 681	depends on CGROUP_MEM_RES_CTLR_SWAP
 682	default y
 683	help
 684	  Memory Resource Controller Swap Extension comes with its price in
 685	  a bigger memory consumption. General purpose distribution kernels
 686	  which want to enable the feature but keep it disabled by default
 687	  and let the user enable it by swapaccount boot command line
 688	  parameter should have this option unselected.
 689	  For those who want to have the feature enabled by default should
 690	  select this option (if, for some reason, they need to disable it
 691	  then swapaccount=0 does the trick).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 692
 693config CGROUP_PERF
 694	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 695	depends on PERF_EVENTS && CGROUPS
 696	help
 697	  This option extends the per-cpu mode to restrict monitoring to
 698	  threads which belong to the cgroup specified and run on the
 699	  designated cpu.
 700
 701	  Say N if unsure.
 702
 703menuconfig CGROUP_SCHED
 704	bool "Group CPU scheduler"
 705	depends on EXPERIMENTAL
 706	default n
 707	help
 708	  This feature lets CPU scheduler recognize task groups and control CPU
 709	  bandwidth allocation to such task groups. It uses cgroups to group
 710	  tasks.
 711
 712if CGROUP_SCHED
 713config FAIR_GROUP_SCHED
 714	bool "Group scheduling for SCHED_OTHER"
 715	depends on CGROUP_SCHED
 716	default CGROUP_SCHED
 717
 
 
 
 
 
 
 
 
 
 
 
 718config RT_GROUP_SCHED
 719	bool "Group scheduling for SCHED_RR/FIFO"
 720	depends on EXPERIMENTAL
 721	depends on CGROUP_SCHED
 722	default n
 723	help
 724	  This feature lets you explicitly allocate real CPU bandwidth
 725	  to task groups. If enabled, it will also make it impossible to
 726	  schedule realtime tasks for non-root users until you allocate
 727	  realtime bandwidth for them.
 728	  See Documentation/scheduler/sched-rt-group.txt for more information.
 729
 730endif #CGROUP_SCHED
 731
 732config BLK_CGROUP
 733	tristate "Block IO controller"
 734	depends on BLOCK
 735	default n
 736	---help---
 737	Generic block IO controller cgroup interface. This is the common
 738	cgroup interface which should be used by various IO controlling
 739	policies.
 740
 741	Currently, CFQ IO scheduler uses it to recognize task groups and
 742	control disk bandwidth allocation (proportional time slice allocation)
 743	to such task groups. It is also used by bio throttling logic in
 744	block layer to implement upper limit in IO rates on a device.
 745
 746	This option only enables generic Block IO controller infrastructure.
 747	One needs to also enable actual IO controlling logic/policy. For
 748	enabling proportional weight division of disk bandwidth in CFQ, set
 749	CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 750	CONFIG_BLK_DEV_THROTTLING=y.
 751
 752	See Documentation/cgroups/blkio-controller.txt for more information.
 753
 754config DEBUG_BLK_CGROUP
 755	bool "Enable Block IO controller debugging"
 756	depends on BLK_CGROUP
 757	default n
 758	---help---
 759	Enable some debugging help. Currently it exports additional stat
 760	files in a cgroup which can be useful for debugging.
 761
 762endif # CGROUPS
 763
 
 
 
 
 
 
 
 
 
 
 
 764menuconfig NAMESPACES
 765	bool "Namespaces support" if EXPERT
 766	default !EXPERT
 767	help
 768	  Provides the way to make tasks work with different objects using
 769	  the same id. For example same IPC id may refer to different objects
 770	  or same user id or pid may refer to different tasks when used in
 771	  different namespaces.
 772
 773if NAMESPACES
 774
 775config UTS_NS
 776	bool "UTS namespace"
 777	default y
 778	help
 779	  In this namespace tasks see different info provided with the
 780	  uname() system call
 781
 782config IPC_NS
 783	bool "IPC namespace"
 784	depends on (SYSVIPC || POSIX_MQUEUE)
 785	default y
 786	help
 787	  In this namespace tasks work with IPC ids which correspond to
 788	  different IPC objects in different namespaces.
 789
 790config USER_NS
 791	bool "User namespace (EXPERIMENTAL)"
 792	depends on EXPERIMENTAL
 793	default y
 794	help
 795	  This allows containers, i.e. vservers, to use user namespaces
 796	  to provide different user info for different servers.
 
 
 
 
 
 
 
 797	  If unsure, say N.
 798
 799config PID_NS
 800	bool "PID Namespaces"
 801	default y
 802	help
 803	  Support process id namespaces.  This allows having multiple
 804	  processes with the same pid as long as they are in different
 805	  pid namespaces.  This is a building block of containers.
 806
 807config NET_NS
 808	bool "Network namespace"
 809	depends on NET
 810	default y
 811	help
 812	  Allow user space to create what appear to be multiple instances
 813	  of the network stack.
 814
 815endif # NAMESPACES
 816
 817config SCHED_AUTOGROUP
 818	bool "Automatic process group scheduling"
 819	select EVENTFD
 820	select CGROUPS
 821	select CGROUP_SCHED
 822	select FAIR_GROUP_SCHED
 823	help
 824	  This option optimizes the scheduler for common desktop workloads by
 825	  automatically creating and populating task groups.  This separation
 826	  of workloads isolates aggressive CPU burners (like build jobs) from
 827	  desktop applications.  Task group autogeneration is currently based
 828	  upon task session.
 829
 830config MM_OWNER
 831	bool
 832
 833config SYSFS_DEPRECATED
 834	bool "Enable deprecated sysfs features to support old userspace tools"
 835	depends on SYSFS
 836	default n
 837	help
 838	  This option adds code that switches the layout of the "block" class
 839	  devices, to not show up in /sys/class/block/, but only in
 840	  /sys/block/.
 841
 842	  This switch is only active when the sysfs.deprecated=1 boot option is
 843	  passed or the SYSFS_DEPRECATED_V2 option is set.
 844
 845	  This option allows new kernels to run on old distributions and tools,
 846	  which might get confused by /sys/class/block/. Since 2007/2008 all
 847	  major distributions and tools handle this just fine.
 848
 849	  Recent distributions and userspace tools after 2009/2010 depend on
 850	  the existence of /sys/class/block/, and will not work with this
 851	  option enabled.
 852
 853	  Only if you are using a new kernel on an old distribution, you might
 854	  need to say Y here.
 855
 856config SYSFS_DEPRECATED_V2
 857	bool "Enable deprecated sysfs features by default"
 858	default n
 859	depends on SYSFS
 860	depends on SYSFS_DEPRECATED
 861	help
 862	  Enable deprecated sysfs by default.
 863
 864	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
 865	  option.
 866
 867	  Only if you are using a new kernel on an old distribution, you might
 868	  need to say Y here. Even then, odds are you would not need it
 869	  enabled, you can always pass the boot option if absolutely necessary.
 870
 871config RELAY
 872	bool "Kernel->user space relay support (formerly relayfs)"
 873	help
 874	  This option enables support for relay interface support in
 875	  certain file systems (such as debugfs).
 876	  It is designed to provide an efficient mechanism for tools and
 877	  facilities to relay large amounts of data from kernel space to
 878	  user space.
 879
 880	  If unsure, say N.
 881
 882config BLK_DEV_INITRD
 883	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 884	depends on BROKEN || !FRV
 885	help
 886	  The initial RAM filesystem is a ramfs which is loaded by the
 887	  boot loader (loadlin or lilo) and that is mounted as root
 888	  before the normal boot procedure. It is typically used to
 889	  load modules needed to mount the "real" root file system,
 890	  etc. See <file:Documentation/initrd.txt> for details.
 891
 892	  If RAM disk support (BLK_DEV_RAM) is also included, this
 893	  also enables initial RAM disk (initrd) support and adds
 894	  15 Kbytes (more on some other architectures) to the kernel size.
 895
 896	  If unsure say Y.
 897
 898if BLK_DEV_INITRD
 899
 900source "usr/Kconfig"
 901
 902endif
 903
 904config CC_OPTIMIZE_FOR_SIZE
 905	bool "Optimize for size"
 906	help
 907	  Enabling this option will pass "-Os" instead of "-O2" to gcc
 908	  resulting in a smaller kernel.
 909
 910	  If unsure, say Y.
 911
 912config SYSCTL
 913	bool
 914
 915config ANON_INODES
 916	bool
 917
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 918menuconfig EXPERT
 919	bool "Configure standard kernel features (expert users)"
 920	# Unhide debug options, to make the on-by-default options visible
 921	select DEBUG_KERNEL
 922	help
 923	  This option allows certain base kernel options and settings
 924          to be disabled or tweaked. This is for specialized
 925          environments which can tolerate a "non-standard" kernel.
 926          Only use this if you really know what you are doing.
 927
 928config UID16
 929	bool "Enable 16-bit UID system calls" if EXPERT
 930	depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
 931	default y
 932	help
 933	  This enables the legacy 16-bit UID syscall wrappers.
 934
 
 
 
 
 
 
 
 
 
 
 935config SYSCTL_SYSCALL
 936	bool "Sysctl syscall support" if EXPERT
 937	depends on PROC_SYSCTL
 938	default y
 939	select SYSCTL
 940	---help---
 941	  sys_sysctl uses binary paths that have been found challenging
 942	  to properly maintain and use.  The interface in /proc/sys
 943	  using paths with ascii names is now the primary path to this
 944	  information.
 945
 946	  Almost nothing using the binary sysctl interface so if you are
 947	  trying to save some space it is probably safe to disable this,
 948	  making your kernel marginally smaller.
 949
 950	  If unsure say Y here.
 951
 952config KALLSYMS
 953	 bool "Load all symbols for debugging/ksymoops" if EXPERT
 954	 default y
 955	 help
 956	   Say Y here to let the kernel print out symbolic crash information and
 957	   symbolic stack backtraces. This increases the size of the kernel
 958	   somewhat, as all symbols have to be loaded into the kernel image.
 959
 960config KALLSYMS_ALL
 961	bool "Include all symbols in kallsyms"
 962	depends on DEBUG_KERNEL && KALLSYMS
 963	help
 964	   Normally kallsyms only contains the symbols of functions for nicer
 965	   OOPS messages and backtraces (i.e., symbols from the text and inittext
 966	   sections). This is sufficient for most cases. And only in very rare
 967	   cases (e.g., when a debugger is used) all symbols are required (e.g.,
 968	   names of variables from the data sections, etc).
 969
 970	   This option makes sure that all symbols are loaded into the kernel
 971	   image (i.e., symbols from all sections) in cost of increased kernel
 972	   size (depending on the kernel configuration, it may be 300KiB or
 973	   something like this).
 974
 975	   Say N unless you really need all symbols.
 976
 977config HOTPLUG
 978	bool "Support for hot-pluggable devices" if EXPERT
 979	default y
 980	help
 981	  This option is provided for the case where no hotplug or uevent
 982	  capabilities is wanted by the kernel.  You should only consider
 983	  disabling this option for embedded systems that do not use modules, a
 984	  dynamic /dev tree, or dynamic device discovery.  Just say Y.
 985
 986config PRINTK
 987	default y
 988	bool "Enable support for printk" if EXPERT
 
 989	help
 990	  This option enables normal printk support. Removing it
 991	  eliminates most of the message strings from the kernel image
 992	  and makes the kernel more or less silent. As this makes it
 993	  very difficult to diagnose system problems, saying N here is
 994	  strongly discouraged.
 995
 996config BUG
 997	bool "BUG() support" if EXPERT
 998	default y
 999	help
1000          Disabling this option eliminates support for BUG and WARN, reducing
1001          the size of your kernel image and potentially quietly ignoring
1002          numerous fatal conditions. You should only consider disabling this
1003          option for embedded systems with no facilities for reporting errors.
1004          Just say Y.
1005
1006config ELF_CORE
 
1007	default y
1008	bool "Enable ELF core dumps" if EXPERT
1009	help
1010	  Enable support for generating core dumps. Disabling saves about 4k.
1011
1012
1013config PCSPKR_PLATFORM
1014	bool "Enable PC-Speaker support" if EXPERT
1015	depends on HAVE_PCSPKR_PLATFORM
1016	select I8253_LOCK
1017	default y
1018	help
1019          This option allows to disable the internal PC-Speaker
1020          support, saving some memory.
1021
1022config HAVE_PCSPKR_PLATFORM
1023	bool
1024
1025config BASE_FULL
1026	default y
1027	bool "Enable full-sized data structures for core" if EXPERT
1028	help
1029	  Disabling this option reduces the size of miscellaneous core
1030	  kernel data structures. This saves memory on small machines,
1031	  but may reduce performance.
1032
1033config FUTEX
1034	bool "Enable futex support" if EXPERT
1035	default y
1036	select RT_MUTEXES
1037	help
1038	  Disabling this option will cause the kernel to be built without
1039	  support for "fast userspace mutexes".  The resulting kernel may not
1040	  run glibc-based applications correctly.
1041
 
 
 
 
 
 
 
1042config EPOLL
1043	bool "Enable eventpoll support" if EXPERT
1044	default y
1045	select ANON_INODES
1046	help
1047	  Disabling this option will cause the kernel to be built without
1048	  support for epoll family of system calls.
1049
1050config SIGNALFD
1051	bool "Enable signalfd() system call" if EXPERT
1052	select ANON_INODES
1053	default y
1054	help
1055	  Enable the signalfd() system call that allows to receive signals
1056	  on a file descriptor.
1057
1058	  If unsure, say Y.
1059
1060config TIMERFD
1061	bool "Enable timerfd() system call" if EXPERT
1062	select ANON_INODES
1063	default y
1064	help
1065	  Enable the timerfd() system call that allows to receive timer
1066	  events on a file descriptor.
1067
1068	  If unsure, say Y.
1069
1070config EVENTFD
1071	bool "Enable eventfd() system call" if EXPERT
1072	select ANON_INODES
1073	default y
1074	help
1075	  Enable the eventfd() system call that allows to receive both
1076	  kernel notification (ie. KAIO) or userspace notifications.
1077
1078	  If unsure, say Y.
1079
1080config SHMEM
1081	bool "Use full shmem filesystem" if EXPERT
1082	default y
1083	depends on MMU
1084	help
1085	  The shmem is an internal filesystem used to manage shared memory.
1086	  It is backed by swap and manages resource limits. It is also exported
1087	  to userspace as tmpfs if TMPFS is enabled. Disabling this
1088	  option replaces shmem and tmpfs with the much simpler ramfs code,
1089	  which may be appropriate on small systems without swap.
1090
1091config AIO
1092	bool "Enable AIO support" if EXPERT
1093	default y
1094	help
1095	  This option enables POSIX asynchronous I/O which may by used
1096          by some high performance threaded applications. Disabling
1097          this option saves about 7k.
 
 
 
 
 
 
 
 
 
1098
1099config EMBEDDED
1100	bool "Embedded system"
 
1101	select EXPERT
1102	help
1103	  This option should be enabled if compiling the kernel for
1104	  an embedded system so certain expert options are available
1105	  for configuration.
1106
1107config HAVE_PERF_EVENTS
1108	bool
1109	help
1110	  See tools/perf/design.txt for details.
1111
1112config PERF_USE_VMALLOC
1113	bool
1114	help
1115	  See tools/perf/design.txt for details
1116
1117menu "Kernel Performance Events And Counters"
1118
1119config PERF_EVENTS
1120	bool "Kernel performance events and counters"
1121	default y if (PROFILING || PERF_COUNTERS)
1122	depends on HAVE_PERF_EVENTS
1123	select ANON_INODES
1124	select IRQ_WORK
1125	help
1126	  Enable kernel support for various performance events provided
1127	  by software and hardware.
1128
1129	  Software events are supported either built-in or via the
1130	  use of generic tracepoints.
1131
1132	  Most modern CPUs support performance events via performance
1133	  counter registers. These registers count the number of certain
1134	  types of hw events: such as instructions executed, cachemisses
1135	  suffered, or branches mis-predicted - without slowing down the
1136	  kernel or applications. These registers can also trigger interrupts
1137	  when a threshold number of events have passed - and can thus be
1138	  used to profile the code that runs on that CPU.
1139
1140	  The Linux Performance Event subsystem provides an abstraction of
1141	  these software and hardware event capabilities, available via a
1142	  system call and used by the "perf" utility in tools/perf/. It
1143	  provides per task and per CPU counters, and it provides event
1144	  capabilities on top of those.
1145
1146	  Say Y if unsure.
1147
1148config PERF_COUNTERS
1149	bool "Kernel performance counters (old config option)"
1150	depends on HAVE_PERF_EVENTS
1151	help
1152	  This config has been obsoleted by the PERF_EVENTS
1153	  config option - please see that one for details.
1154
1155	  It has no effect on the kernel whether you enable
1156	  it or not, it is a compatibility placeholder.
1157
1158	  Say N if unsure.
1159
1160config DEBUG_PERF_USE_VMALLOC
1161	default n
1162	bool "Debug: use vmalloc to back perf mmap() buffers"
1163	depends on PERF_EVENTS && DEBUG_KERNEL
1164	select PERF_USE_VMALLOC
1165	help
1166	 Use vmalloc memory to back perf mmap() buffers.
1167
1168	 Mostly useful for debugging the vmalloc code on platforms
1169	 that don't require it.
1170
1171	 Say N if unsure.
1172
1173endmenu
1174
1175config VM_EVENT_COUNTERS
1176	default y
1177	bool "Enable VM event counters for /proc/vmstat" if EXPERT
1178	help
1179	  VM event counters are needed for event counts to be shown.
1180	  This option allows the disabling of the VM event counters
1181	  on EXPERT systems.  /proc/vmstat will only show page counts
1182	  if VM event counters are disabled.
1183
1184config PCI_QUIRKS
1185	default y
1186	bool "Enable PCI quirk workarounds" if EXPERT
1187	depends on PCI
1188	help
1189	  This enables workarounds for various PCI chipset
1190          bugs/quirks. Disable this only if your target machine is
1191          unaffected by PCI quirks.
1192
1193config SLUB_DEBUG
1194	default y
1195	bool "Enable SLUB debugging support" if EXPERT
1196	depends on SLUB && SYSFS
1197	help
1198	  SLUB has extensive debug support features. Disabling these can
1199	  result in significant savings in code size. This also disables
1200	  SLUB sysfs support. /sys/slab will not exist and there will be
1201	  no support for cache validation etc.
1202
1203config COMPAT_BRK
1204	bool "Disable heap randomization"
1205	default y
1206	help
1207	  Randomizing heap placement makes heap exploits harder, but it
1208	  also breaks ancient binaries (including anything libc5 based).
1209	  This option changes the bootup default to heap randomization
1210	  disabled, and can be overridden at runtime by setting
1211	  /proc/sys/kernel/randomize_va_space to 2.
1212
1213	  On non-ancient distros (post-2000 ones) N is usually a safe choice.
1214
1215choice
1216	prompt "Choose SLAB allocator"
1217	default SLUB
1218	help
1219	   This option allows to select a slab allocator.
1220
1221config SLAB
1222	bool "SLAB"
1223	help
1224	  The regular slab allocator that is established and known to work
1225	  well in all environments. It organizes cache hot objects in
1226	  per cpu and per node queues.
1227
1228config SLUB
1229	bool "SLUB (Unqueued Allocator)"
1230	help
1231	   SLUB is a slab allocator that minimizes cache line usage
1232	   instead of managing queues of cached objects (SLAB approach).
1233	   Per cpu caching is realized using slabs of objects instead
1234	   of queues of objects. SLUB can use memory efficiently
1235	   and has enhanced diagnostics. SLUB is the default choice for
1236	   a slab allocator.
1237
1238config SLOB
1239	depends on EXPERT
1240	bool "SLOB (Simple Allocator)"
1241	help
1242	   SLOB replaces the stock allocator with a drastically simpler
1243	   allocator. SLOB is generally more space efficient but
1244	   does not perform as well on large systems.
1245
1246endchoice
1247
 
 
 
 
 
 
 
 
 
 
 
1248config MMAP_ALLOW_UNINITIALIZED
1249	bool "Allow mmapped anonymous memory to be uninitialized"
1250	depends on EXPERT && !MMU
1251	default n
1252	help
1253	  Normally, and according to the Linux spec, anonymous memory obtained
1254	  from mmap() has it's contents cleared before it is passed to
1255	  userspace.  Enabling this config option allows you to request that
1256	  mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1257	  providing a huge performance boost.  If this option is not enabled,
1258	  then the flag will be ignored.
1259
1260	  This is taken advantage of by uClibc's malloc(), and also by
1261	  ELF-FDPIC binfmt's brk and stack allocator.
1262
1263	  Because of the obvious security issues, this option should only be
1264	  enabled on embedded devices where you control what is run in
1265	  userspace.  Since that isn't generally a problem on no-MMU systems,
1266	  it is normally safe to say Y here.
1267
1268	  See Documentation/nommu-mmap.txt for more information.
1269
 
 
 
 
 
 
 
 
 
 
 
 
1270config PROFILING
1271	bool "Profiling support"
1272	help
1273	  Say Y here to enable the extended profiling support mechanisms used
1274	  by profilers such as OProfile.
1275
1276#
1277# Place an empty function call at each tracepoint site. Can be
1278# dynamically changed for a probe function.
1279#
1280config TRACEPOINTS
1281	bool
1282
1283source "arch/Kconfig"
1284
1285endmenu		# General setup
1286
1287config HAVE_GENERIC_DMA_COHERENT
1288	bool
1289	default n
1290
1291config SLABINFO
1292	bool
1293	depends on PROC_FS
1294	depends on SLAB || SLUB_DEBUG
1295	default y
1296
1297config RT_MUTEXES
1298	boolean
1299
1300config BASE_SMALL
1301	int
1302	default 0 if BASE_FULL
1303	default 1 if !BASE_FULL
1304
1305menuconfig MODULES
1306	bool "Enable loadable module support"
 
1307	help
1308	  Kernel modules are small pieces of compiled code which can
1309	  be inserted in the running kernel, rather than being
1310	  permanently built into the kernel.  You use the "modprobe"
1311	  tool to add (and sometimes remove) them.  If you say Y here,
1312	  many parts of the kernel can be built as modules (by
1313	  answering M instead of Y where indicated): this is most
1314	  useful for infrequently used options which are not required
1315	  for booting.  For more information, see the man pages for
1316	  modprobe, lsmod, modinfo, insmod and rmmod.
1317
1318	  If you say Y here, you will need to run "make
1319	  modules_install" to put the modules under /lib/modules/
1320	  where modprobe can find them (you may need to be root to do
1321	  this).
1322
1323	  If unsure, say Y.
1324
1325if MODULES
1326
1327config MODULE_FORCE_LOAD
1328	bool "Forced module loading"
1329	default n
1330	help
1331	  Allow loading of modules without version information (ie. modprobe
1332	  --force).  Forced module loading sets the 'F' (forced) taint flag and
1333	  is usually a really bad idea.
1334
1335config MODULE_UNLOAD
1336	bool "Module unloading"
1337	help
1338	  Without this option you will not be able to unload any
1339	  modules (note that some modules may not be unloadable
1340	  anyway), which makes your kernel smaller, faster
1341	  and simpler.  If unsure, say Y.
1342
1343config MODULE_FORCE_UNLOAD
1344	bool "Forced module unloading"
1345	depends on MODULE_UNLOAD && EXPERIMENTAL
1346	help
1347	  This option allows you to force a module to unload, even if the
1348	  kernel believes it is unsafe: the kernel will remove the module
1349	  without waiting for anyone to stop using it (using the -f option to
1350	  rmmod).  This is mainly for kernel developers and desperate users.
1351	  If unsure, say N.
1352
1353config MODVERSIONS
1354	bool "Module versioning support"
1355	help
1356	  Usually, you have to use modules compiled with your kernel.
1357	  Saying Y here makes it sometimes possible to use modules
1358	  compiled for different kernels, by adding enough information
1359	  to the modules to (hopefully) spot any changes which would
1360	  make them incompatible with the kernel you are running.  If
1361	  unsure, say N.
1362
1363config MODULE_SRCVERSION_ALL
1364	bool "Source checksum for all modules"
1365	help
1366	  Modules which contain a MODULE_VERSION get an extra "srcversion"
1367	  field inserted into their modinfo section, which contains a
1368    	  sum of the source files which made it.  This helps maintainers
1369	  see exactly which source was used to build a module (since
1370	  others sometimes change the module source without updating
1371	  the version).  With this option, such a "srcversion" field
1372	  will be created for all modules.  If unsure, say N.
1373
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1374endif # MODULES
1375
1376config INIT_ALL_POSSIBLE
1377	bool
1378	help
1379	  Back when each arch used to define their own cpu_online_map and
1380	  cpu_possible_map, some of them chose to initialize cpu_possible_map
1381	  with all 1s, and others with all 0s.  When they were centralised,
1382	  it was better to provide this option than to break all the archs
1383	  and have several arch maintainers pursuing me down dark alleys.
1384
1385config STOP_MACHINE
1386	bool
1387	default y
1388	depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1389	help
1390	  Need stop_machine() primitive.
1391
1392source "block/Kconfig"
1393
1394config PREEMPT_NOTIFIERS
1395	bool
1396
1397config PADATA
1398	depends on SMP
1399	bool
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1400
1401source "kernel/Kconfig.locks"

   1config ARCH
   2	string
   3	option env="ARCH"
   4
   5config KERNELVERSION
   6	string
   7	option env="KERNELVERSION"
   8
   9config 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
  19config CONSTRUCTORS
  20	bool
  21	depends on !UML
  22
  23config IRQ_WORK
  24	bool
  25
  26config BUILDTIME_EXTABLE_SORT
  27	bool
 
  28
  29menu "General setup"
  30
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  31config BROKEN
  32	bool
  33
  34config BROKEN_ON_SMP
  35	bool
  36	depends on BROKEN || !SMP
  37	default y
  38
  39config INIT_ENV_ARG_LIMIT
  40	int
  41	default 32 if !UML
  42	default 128 if UML
  43	help
  44	  Maximum of each of the number of arguments and environment
  45	  variables passed to init from the kernel command line.
  46
  47
  48config CROSS_COMPILE
  49	string "Cross-compiler tool prefix"
  50	help
  51	  Same as running 'make CROSS_COMPILE=prefix-' but stored for
  52	  default make runs in this kernel build directory.  You don't
  53	  need to set this unless you want the configured kernel build
  54	  directory to select the cross-compiler automatically.
  55
  56config COMPILE_TEST
  57	bool "Compile also drivers which will not load"
  58	default n
  59	help
  60	  Some drivers can be compiled on a different platform than they are
  61	  intended to be run on. Despite they cannot be loaded there (or even
  62	  when they load they cannot be used due to missing HW support),
  63	  developers still, opposing to distributors, might want to build such
  64	  drivers to compile-test them.
  65
  66	  If you are a developer and want to build everything available, say Y
  67	  here. If you are a user/distributor, say N here to exclude useless
  68	  drivers to be distributed.
  69
  70config LOCALVERSION
  71	string "Local version - append to kernel release"
  72	help
  73	  Append an extra string to the end of your kernel version.
  74	  This will show up when you type uname, for example.
  75	  The string you set here will be appended after the contents of
  76	  any files with a filename matching localversion* in your
  77	  object and source tree, in that order.  Your total string can
  78	  be a maximum of 64 characters.
  79
  80config LOCALVERSION_AUTO
  81	bool "Automatically append version information to the version string"
  82	default y
  83	help
  84	  This will try to automatically determine if the current tree is a
  85	  release tree by looking for git tags that belong to the current
  86	  top of tree revision.
  87
  88	  A string of the format -gxxxxxxxx will be added to the localversion
  89	  if a git-based tree is found.  The string generated by this will be
  90	  appended after any matching localversion* files, and after the value
  91	  set in CONFIG_LOCALVERSION.
  92
  93	  (The actual string used here is the first eight characters produced
  94	  by running the command:
  95
  96	    $ git rev-parse --verify HEAD
  97
  98	  which is done within the script "scripts/setlocalversion".)
  99
 100config HAVE_KERNEL_GZIP
 101	bool
 102
 103config HAVE_KERNEL_BZIP2
 104	bool
 105
 106config HAVE_KERNEL_LZMA
 107	bool
 108
 109config HAVE_KERNEL_XZ
 110	bool
 111
 112config HAVE_KERNEL_LZO
 113	bool
 114
 115config HAVE_KERNEL_LZ4
 116	bool
 117
 118choice
 119	prompt "Kernel compression mode"
 120	default KERNEL_GZIP
 121	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
 122	help
 123	  The linux kernel is a kind of self-extracting executable.
 124	  Several compression algorithms are available, which differ
 125	  in efficiency, compression and decompression speed.
 126	  Compression speed is only relevant when building a kernel.
 127	  Decompression speed is relevant at each boot.
 128
 129	  If you have any problems with bzip2 or lzma compressed
 130	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
 131	  version of this functionality (bzip2 only), for 2.4, was
 132	  supplied by Christian Ludwig)
 133
 134	  High compression options are mostly useful for users, who
 135	  are low on disk space (embedded systems), but for whom ram
 136	  size matters less.
 137
 138	  If in doubt, select 'gzip'
 139
 140config KERNEL_GZIP
 141	bool "Gzip"
 142	depends on HAVE_KERNEL_GZIP
 143	help
 144	  The old and tried gzip compression. It provides a good balance
 145	  between compression ratio and decompression speed.
 146
 147config KERNEL_BZIP2
 148	bool "Bzip2"
 149	depends on HAVE_KERNEL_BZIP2
 150	help
 151	  Its compression ratio and speed is intermediate.
 152	  Decompression speed is slowest among the choices.  The kernel
 153	  size is about 10% smaller with bzip2, in comparison to gzip.
 154	  Bzip2 uses a large amount of memory. For modern kernels you
 155	  will need at least 8MB RAM or more for booting.
 156
 157config KERNEL_LZMA
 158	bool "LZMA"
 159	depends on HAVE_KERNEL_LZMA
 160	help
 161	  This compression algorithm's ratio is best.  Decompression speed
 162	  is between gzip and bzip2.  Compression is slowest.
 163	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
 
 164
 165config KERNEL_XZ
 166	bool "XZ"
 167	depends on HAVE_KERNEL_XZ
 168	help
 169	  XZ uses the LZMA2 algorithm and instruction set specific
 170	  BCJ filters which can improve compression ratio of executable
 171	  code. The size of the kernel is about 30% smaller with XZ in
 172	  comparison to gzip. On architectures for which there is a BCJ
 173	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
 174	  will create a few percent smaller kernel than plain LZMA.
 175
 176	  The speed is about the same as with LZMA: The decompression
 177	  speed of XZ is better than that of bzip2 but worse than gzip
 178	  and LZO. Compression is slow.
 179
 180config KERNEL_LZO
 181	bool "LZO"
 182	depends on HAVE_KERNEL_LZO
 183	help
 184	  Its compression ratio is the poorest among the choices. The kernel
 185	  size is about 10% bigger than gzip; however its speed
 186	  (both compression and decompression) is the fastest.
 187
 188config KERNEL_LZ4
 189	bool "LZ4"
 190	depends on HAVE_KERNEL_LZ4
 191	help
 192	  LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
 193	  A preliminary version of LZ4 de/compression tool is available at
 194	  <https://code.google.com/p/lz4/>.
 195
 196	  Its compression ratio is worse than LZO. The size of the kernel
 197	  is about 8% bigger than LZO. But the decompression speed is
 198	  faster than LZO.
 199
 200endchoice
 201
 202config DEFAULT_HOSTNAME
 203	string "Default hostname"
 204	default "(none)"
 205	help
 206	  This option determines the default system hostname before userspace
 207	  calls sethostname(2). The kernel traditionally uses "(none)" here,
 208	  but you may wish to use a different default here to make a minimal
 209	  system more usable with less configuration.
 210
 211config SWAP
 212	bool "Support for paging of anonymous memory (swap)"
 213	depends on MMU && BLOCK
 214	default y
 215	help
 216	  This option allows you to choose whether you want to have support
 217	  for so called swap devices or swap files in your kernel that are
 218	  used to provide more virtual memory than the actual RAM present
 219	  in your computer.  If unsure say Y.
 220
 221config SYSVIPC
 222	bool "System V IPC"
 223	---help---
 224	  Inter Process Communication is a suite of library functions and
 225	  system calls which let processes (running programs) synchronize and
 226	  exchange information. It is generally considered to be a good thing,
 227	  and some programs won't run unless you say Y here. In particular, if
 228	  you want to run the DOS emulator dosemu under Linux (read the
 229	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
 230	  you'll need to say Y here.
 231
 232	  You can find documentation about IPC with "info ipc" and also in
 233	  section 6.4 of the Linux Programmer's Guide, available from
 234	  <http://www.tldp.org/guides.html>.
 235
 236config SYSVIPC_SYSCTL
 237	bool
 238	depends on SYSVIPC
 239	depends on SYSCTL
 240	default y
 241
 242config POSIX_MQUEUE
 243	bool "POSIX Message Queues"
 244	depends on NET
 245	---help---
 246	  POSIX variant of message queues is a part of IPC. In POSIX message
 247	  queues every message has a priority which decides about succession
 248	  of receiving it by a process. If you want to compile and run
 249	  programs written e.g. for Solaris with use of its POSIX message
 250	  queues (functions mq_*) say Y here.
 251
 252	  POSIX message queues are visible as a filesystem called 'mqueue'
 253	  and can be mounted somewhere if you want to do filesystem
 254	  operations on message queues.
 255
 256	  If unsure, say Y.
 257
 258config POSIX_MQUEUE_SYSCTL
 259	bool
 260	depends on POSIX_MQUEUE
 261	depends on SYSCTL
 262	default y
 263
 264config FHANDLE
 265	bool "open by fhandle syscalls"
 266	select EXPORTFS
 267	help
 268	  If you say Y here, a user level program will be able to map
 269	  file names to handle and then later use the handle for
 270	  different file system operations. This is useful in implementing
 271	  userspace file servers, which now track files using handles instead
 272	  of names. The handle would remain the same even if file names
 273	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
 274	  syscalls.
 275
 276config USELIB
 277	bool "uselib syscall"
 278	default y
 279	help
 280	  This option enables the uselib syscall, a system call used in the
 281	  dynamic linker from libc5 and earlier.  glibc does not use this
 282	  system call.  If you intend to run programs built on libc5 or
 283	  earlier, you may need to enable this syscall.  Current systems
 284	  running glibc can safely disable this.
 285
 286config AUDIT
 287	bool "Auditing support"
 288	depends on NET
 289	help
 290	  Enable auditing infrastructure that can be used with another
 291	  kernel subsystem, such as SELinux (which requires this for
 292	  logging of avc messages output).  Does not do system-call
 293	  auditing without CONFIG_AUDITSYSCALL.
 294
 295config HAVE_ARCH_AUDITSYSCALL
 296	bool
 297
 298config AUDITSYSCALL
 299	bool "Enable system-call auditing support"
 300	depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
 301	default y if SECURITY_SELINUX
 302	help
 303	  Enable low-overhead system-call auditing infrastructure that
 304	  can be used independently or with another kernel subsystem,
 305	  such as SELinux.
 306
 307config AUDIT_WATCH
 308	def_bool y
 309	depends on AUDITSYSCALL
 310	select FSNOTIFY
 311
 312config AUDIT_TREE
 313	def_bool y
 314	depends on AUDITSYSCALL
 315	select FSNOTIFY
 316
 317source "kernel/irq/Kconfig"
 318source "kernel/time/Kconfig"
 319
 320menu "CPU/Task time and stats accounting"
 321
 322config VIRT_CPU_ACCOUNTING
 323	bool
 324
 325choice
 326	prompt "Cputime accounting"
 327	default TICK_CPU_ACCOUNTING if !PPC64
 328	default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
 329
 330# Kind of a stub config for the pure tick based cputime accounting
 331config TICK_CPU_ACCOUNTING
 332	bool "Simple tick based cputime accounting"
 333	depends on !S390 && !NO_HZ_FULL
 334	help
 335	  This is the basic tick based cputime accounting that maintains
 336	  statistics about user, system and idle time spent on per jiffies
 337	  granularity.
 338
 339	  If unsure, say Y.
 340
 341config VIRT_CPU_ACCOUNTING_NATIVE
 342	bool "Deterministic task and CPU time accounting"
 343	depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
 344	select VIRT_CPU_ACCOUNTING
 345	help
 346	  Select this option to enable more accurate task and CPU time
 347	  accounting.  This is done by reading a CPU counter on each
 348	  kernel entry and exit and on transitions within the kernel
 349	  between system, softirq and hardirq state, so there is a
 350	  small performance impact.  In the case of s390 or IBM POWER > 5,
 351	  this also enables accounting of stolen time on logically-partitioned
 352	  systems.
 353
 354config VIRT_CPU_ACCOUNTING_GEN
 355	bool "Full dynticks CPU time accounting"
 356	depends on HAVE_CONTEXT_TRACKING
 357	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
 358	select VIRT_CPU_ACCOUNTING
 359	select CONTEXT_TRACKING
 360	help
 361	  Select this option to enable task and CPU time accounting on full
 362	  dynticks systems. This accounting is implemented by watching every
 363	  kernel-user boundaries using the context tracking subsystem.
 364	  The accounting is thus performed at the expense of some significant
 365	  overhead.
 366
 367	  For now this is only useful if you are working on the full
 368	  dynticks subsystem development.
 369
 370	  If unsure, say N.
 371
 372config IRQ_TIME_ACCOUNTING
 373	bool "Fine granularity task level IRQ time accounting"
 374	depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
 375	help
 376	  Select this option to enable fine granularity task irq time
 377	  accounting. This is done by reading a timestamp on each
 378	  transitions between softirq and hardirq state, so there can be a
 379	  small performance impact.
 380
 381	  If in doubt, say N here.
 382
 383endchoice
 384
 385config BSD_PROCESS_ACCT
 386	bool "BSD Process Accounting"
 387	help
 388	  If you say Y here, a user level program will be able to instruct the
 389	  kernel (via a special system call) to write process accounting
 390	  information to a file: whenever a process exits, information about
 391	  that process will be appended to the file by the kernel.  The
 392	  information includes things such as creation time, owning user,
 393	  command name, memory usage, controlling terminal etc. (the complete
 394	  list is in the struct acct in <file:include/linux/acct.h>).  It is
 395	  up to the user level program to do useful things with this
 396	  information.  This is generally a good idea, so say Y.
 397
 398config BSD_PROCESS_ACCT_V3
 399	bool "BSD Process Accounting version 3 file format"
 400	depends on BSD_PROCESS_ACCT
 401	default n
 402	help
 403	  If you say Y here, the process accounting information is written
 404	  in a new file format that also logs the process IDs of each
 405	  process and it's parent. Note that this file format is incompatible
 406	  with previous v0/v1/v2 file formats, so you will need updated tools
 407	  for processing it. A preliminary version of these tools is available
 408	  at <http://www.gnu.org/software/acct/>.
 409
 
 
 
 
 
 
 
 
 
 
 
 
 410config TASKSTATS
 411	bool "Export task/process statistics through netlink"
 412	depends on NET
 413	default n
 414	help
 415	  Export selected statistics for tasks/processes through the
 416	  generic netlink interface. Unlike BSD process accounting, the
 417	  statistics are available during the lifetime of tasks/processes as
 418	  responses to commands. Like BSD accounting, they are sent to user
 419	  space on task exit.
 420
 421	  Say N if unsure.
 422
 423config TASK_DELAY_ACCT
 424	bool "Enable per-task delay accounting"
 425	depends on TASKSTATS
 426	help
 427	  Collect information on time spent by a task waiting for system
 428	  resources like cpu, synchronous block I/O completion and swapping
 429	  in pages. Such statistics can help in setting a task's priorities
 430	  relative to other tasks for cpu, io, rss limits etc.
 431
 432	  Say N if unsure.
 433
 434config TASK_XACCT
 435	bool "Enable extended accounting over taskstats"
 436	depends on TASKSTATS
 437	help
 438	  Collect extended task accounting data and send the data
 439	  to userland for processing over the taskstats interface.
 440
 441	  Say N if unsure.
 442
 443config TASK_IO_ACCOUNTING
 444	bool "Enable per-task storage I/O accounting"
 445	depends on TASK_XACCT
 446	help
 447	  Collect information on the number of bytes of storage I/O which this
 448	  task has caused.
 449
 450	  Say N if unsure.
 451
 452endmenu # "CPU/Task time and stats accounting"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 453
 454menu "RCU Subsystem"
 455
 456choice
 457	prompt "RCU Implementation"
 458	default TREE_RCU
 459
 460config TREE_RCU
 461	bool "Tree-based hierarchical RCU"
 462	depends on !PREEMPT && SMP
 463	select IRQ_WORK
 464	help
 465	  This option selects the RCU implementation that is
 466	  designed for very large SMP system with hundreds or
 467	  thousands of CPUs.  It also scales down nicely to
 468	  smaller systems.
 469
 470config TREE_PREEMPT_RCU
 471	bool "Preemptible tree-based hierarchical RCU"
 472	depends on PREEMPT
 473	select IRQ_WORK
 474	help
 475	  This option selects the RCU implementation that is
 476	  designed for very large SMP systems with hundreds or
 477	  thousands of CPUs, but for which real-time response
 478	  is also required.  It also scales down nicely to
 479	  smaller systems.
 480
 481	  Select this option if you are unsure.
 482
 483config TINY_RCU
 484	bool "UP-only small-memory-footprint RCU"
 485	depends on !PREEMPT && !SMP
 486	help
 487	  This option selects the RCU implementation that is
 488	  designed for UP systems from which real-time response
 489	  is not required.  This option greatly reduces the
 490	  memory footprint of RCU.
 491
 
 
 
 
 
 
 
 
 492endchoice
 493
 494config PREEMPT_RCU
 495	def_bool TREE_PREEMPT_RCU
 496	help
 497	  This option enables preemptible-RCU code that is common between
 498	  the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
 499
 500config RCU_STALL_COMMON
 501	def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
 502	help
 503	  This option enables RCU CPU stall code that is common between
 504	  the TINY and TREE variants of RCU.  The purpose is to allow
 505	  the tiny variants to disable RCU CPU stall warnings, while
 506	  making these warnings mandatory for the tree variants.
 507
 508config CONTEXT_TRACKING
 509       bool
 510
 511config RCU_USER_QS
 512	bool "Consider userspace as in RCU extended quiescent state"
 513	depends on HAVE_CONTEXT_TRACKING && SMP
 514	select CONTEXT_TRACKING
 515	help
 516	  This option sets hooks on kernel / userspace boundaries and
 517	  puts RCU in extended quiescent state when the CPU runs in
 518	  userspace. It means that when a CPU runs in userspace, it is
 519	  excluded from the global RCU state machine and thus doesn't
 520	  try to keep the timer tick on for RCU.
 521
 522	  Unless you want to hack and help the development of the full
 523	  dynticks mode, you shouldn't enable this option.  It also
 524	  adds unnecessary overhead.
 525
 526	  If unsure say N
 527
 528config CONTEXT_TRACKING_FORCE
 529	bool "Force context tracking"
 530	depends on CONTEXT_TRACKING
 531	default y if !NO_HZ_FULL
 532	help
 533	  The major pre-requirement for full dynticks to work is to
 534	  support the context tracking subsystem. But there are also
 535	  other dependencies to provide in order to make the full
 536	  dynticks working.
 537
 538	  This option stands for testing when an arch implements the
 539	  context tracking backend but doesn't yet fullfill all the
 540	  requirements to make the full dynticks feature working.
 541	  Without the full dynticks, there is no way to test the support
 542	  for context tracking and the subsystems that rely on it: RCU
 543	  userspace extended quiescent state and tickless cputime
 544	  accounting. This option copes with the absence of the full
 545	  dynticks subsystem by forcing the context tracking on all
 546	  CPUs in the system.
 547
 548	  Say Y only if you're working on the development of an
 549	  architecture backend for the context tracking.
 550
 551	  Say N otherwise, this option brings an overhead that you
 552	  don't want in production.
 553
 
 
 554
 555config RCU_FANOUT
 556	int "Tree-based hierarchical RCU fanout value"
 557	range 2 64 if 64BIT
 558	range 2 32 if !64BIT
 559	depends on TREE_RCU || TREE_PREEMPT_RCU
 560	default 64 if 64BIT
 561	default 32 if !64BIT
 562	help
 563	  This option controls the fanout of hierarchical implementations
 564	  of RCU, allowing RCU to work efficiently on machines with
 565	  large numbers of CPUs.  This value must be at least the fourth
 566	  root of NR_CPUS, which allows NR_CPUS to be insanely large.
 567	  The default value of RCU_FANOUT should be used for production
 568	  systems, but if you are stress-testing the RCU implementation
 569	  itself, small RCU_FANOUT values allow you to test large-system
 570	  code paths on small(er) systems.
 571
 572	  Select a specific number if testing RCU itself.
 573	  Take the default if unsure.
 574
 575config RCU_FANOUT_LEAF
 576	int "Tree-based hierarchical RCU leaf-level fanout value"
 577	range 2 RCU_FANOUT if 64BIT
 578	range 2 RCU_FANOUT if !64BIT
 579	depends on TREE_RCU || TREE_PREEMPT_RCU
 580	default 16
 581	help
 582	  This option controls the leaf-level fanout of hierarchical
 583	  implementations of RCU, and allows trading off cache misses
 584	  against lock contention.  Systems that synchronize their
 585	  scheduling-clock interrupts for energy-efficiency reasons will
 586	  want the default because the smaller leaf-level fanout keeps
 587	  lock contention levels acceptably low.  Very large systems
 588	  (hundreds or thousands of CPUs) will instead want to set this
 589	  value to the maximum value possible in order to reduce the
 590	  number of cache misses incurred during RCU's grace-period
 591	  initialization.  These systems tend to run CPU-bound, and thus
 592	  are not helped by synchronized interrupts, and thus tend to
 593	  skew them, which reduces lock contention enough that large
 594	  leaf-level fanouts work well.
 595
 596	  Select a specific number if testing RCU itself.
 597
 598	  Select the maximum permissible value for large systems.
 599
 600	  Take the default if unsure.
 601
 602config RCU_FANOUT_EXACT
 603	bool "Disable tree-based hierarchical RCU auto-balancing"
 604	depends on TREE_RCU || TREE_PREEMPT_RCU
 605	default n
 606	help
 607	  This option forces use of the exact RCU_FANOUT value specified,
 608	  regardless of imbalances in the hierarchy.  This is useful for
 609	  testing RCU itself, and might one day be useful on systems with
 610	  strong NUMA behavior.
 611
 612	  Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
 613
 614	  Say N if unsure.
 615
 616config RCU_FAST_NO_HZ
 617	bool "Accelerate last non-dyntick-idle CPU's grace periods"
 618	depends on NO_HZ_COMMON && SMP
 619	default n
 620	help
 621	  This option permits CPUs to enter dynticks-idle state even if
 622	  they have RCU callbacks queued, and prevents RCU from waking
 623	  these CPUs up more than roughly once every four jiffies (by
 624	  default, you can adjust this using the rcutree.rcu_idle_gp_delay
 625	  parameter), thus improving energy efficiency.  On the other
 626	  hand, this option increases the duration of RCU grace periods,
 627	  for example, slowing down synchronize_rcu().
 628
 629	  Say Y if energy efficiency is critically important, and you
 630	  	don't care about increased grace-period durations.
 631
 632	  Say N if you are unsure.
 633
 634config TREE_RCU_TRACE
 635	def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
 636	select DEBUG_FS
 637	help
 638	  This option provides tracing for the TREE_RCU and
 639	  TREE_PREEMPT_RCU implementations, permitting Makefile to
 640	  trivially select kernel/rcutree_trace.c.
 641
 642config RCU_BOOST
 643	bool "Enable RCU priority boosting"
 644	depends on RT_MUTEXES && PREEMPT_RCU
 645	default n
 646	help
 647	  This option boosts the priority of preempted RCU readers that
 648	  block the current preemptible RCU grace period for too long.
 649	  This option also prevents heavy loads from blocking RCU
 650	  callback invocation for all flavors of RCU.
 651
 652	  Say Y here if you are working with real-time apps or heavy loads
 653	  Say N here if you are unsure.
 654
 655config RCU_BOOST_PRIO
 656	int "Real-time priority to boost RCU readers to"
 657	range 1 99
 658	depends on RCU_BOOST
 659	default 1
 660	help
 661	  This option specifies the real-time priority to which long-term
 662	  preempted RCU readers are to be boosted.  If you are working
 663	  with a real-time application that has one or more CPU-bound
 664	  threads running at a real-time priority level, you should set
 665	  RCU_BOOST_PRIO to a priority higher then the highest-priority
 666	  real-time CPU-bound thread.  The default RCU_BOOST_PRIO value
 667	  of 1 is appropriate in the common case, which is real-time
 668	  applications that do not have any CPU-bound threads.
 669
 670	  Some real-time applications might not have a single real-time
 671	  thread that saturates a given CPU, but instead might have
 672	  multiple real-time threads that, taken together, fully utilize
 673	  that CPU.  In this case, you should set RCU_BOOST_PRIO to
 674	  a priority higher than the lowest-priority thread that is
 675	  conspiring to prevent the CPU from running any non-real-time
 676	  tasks.  For example, if one thread at priority 10 and another
 677	  thread at priority 5 are between themselves fully consuming
 678	  the CPU time on a given CPU, then RCU_BOOST_PRIO should be
 679	  set to priority 6 or higher.
 680
 681	  Specify the real-time priority, or take the default if unsure.
 682
 683config RCU_BOOST_DELAY
 684	int "Milliseconds to delay boosting after RCU grace-period start"
 685	range 0 3000
 686	depends on RCU_BOOST
 687	default 500
 688	help
 689	  This option specifies the time to wait after the beginning of
 690	  a given grace period before priority-boosting preempted RCU
 691	  readers blocking that grace period.  Note that any RCU reader
 692	  blocking an expedited RCU grace period is boosted immediately.
 693
 694	  Accept the default if unsure.
 695
 696config RCU_NOCB_CPU
 697	bool "Offload RCU callback processing from boot-selected CPUs"
 698	depends on TREE_RCU || TREE_PREEMPT_RCU
 699	default n
 700	help
 701	  Use this option to reduce OS jitter for aggressive HPC or
 702	  real-time workloads.	It can also be used to offload RCU
 703	  callback invocation to energy-efficient CPUs in battery-powered
 704	  asymmetric multiprocessors.
 705
 706	  This option offloads callback invocation from the set of
 707	  CPUs specified at boot time by the rcu_nocbs parameter.
 708	  For each such CPU, a kthread ("rcuox/N") will be created to
 709	  invoke callbacks, where the "N" is the CPU being offloaded,
 710	  and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
 711	  "s" for RCU-sched.  Nothing prevents this kthread from running
 712	  on the specified CPUs, but (1) the kthreads may be preempted
 713	  between each callback, and (2) affinity or cgroups can be used
 714	  to force the kthreads to run on whatever set of CPUs is desired.
 715
 716	  Say Y here if you want to help to debug reduced OS jitter.
 717	  Say N here if you are unsure.
 718
 719choice
 720	prompt "Build-forced no-CBs CPUs"
 721	default RCU_NOCB_CPU_NONE
 722	help
 723	  This option allows no-CBs CPUs (whose RCU callbacks are invoked
 724	  from kthreads rather than from softirq context) to be specified
 725	  at build time.  Additional no-CBs CPUs may be specified by
 726	  the rcu_nocbs= boot parameter.
 727
 728config RCU_NOCB_CPU_NONE
 729	bool "No build_forced no-CBs CPUs"
 730	depends on RCU_NOCB_CPU && !NO_HZ_FULL
 731	help
 732	  This option does not force any of the CPUs to be no-CBs CPUs.
 733	  Only CPUs designated by the rcu_nocbs= boot parameter will be
 734	  no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
 735	  kthreads whose names begin with "rcuo".  All other CPUs will
 736	  invoke their own RCU callbacks in softirq context.
 737
 738	  Select this option if you want to choose no-CBs CPUs at
 739	  boot time, for example, to allow testing of different no-CBs
 740	  configurations without having to rebuild the kernel each time.
 741
 742config RCU_NOCB_CPU_ZERO
 743	bool "CPU 0 is a build_forced no-CBs CPU"
 744	depends on RCU_NOCB_CPU && !NO_HZ_FULL
 745	help
 746	  This option forces CPU 0 to be a no-CBs CPU, so that its RCU
 747	  callbacks are invoked by a per-CPU kthread whose name begins
 748	  with "rcuo".	Additional CPUs may be designated as no-CBs
 749	  CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
 750	  All other CPUs will invoke their own RCU callbacks in softirq
 751	  context.
 752
 753	  Select this if CPU 0 needs to be a no-CBs CPU for real-time
 754	  or energy-efficiency reasons, but the real reason it exists
 755	  is to ensure that randconfig testing covers mixed systems.
 756
 757config RCU_NOCB_CPU_ALL
 758	bool "All CPUs are build_forced no-CBs CPUs"
 759	depends on RCU_NOCB_CPU
 760	help
 761	  This option forces all CPUs to be no-CBs CPUs.  The rcu_nocbs=
 762	  boot parameter will be ignored.  All CPUs' RCU callbacks will
 763	  be executed in the context of per-CPU rcuo kthreads created for
 764	  this purpose.  Assuming that the kthreads whose names start with
 765	  "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
 766	  on the remaining CPUs, but might decrease memory locality during
 767	  RCU-callback invocation, thus potentially degrading throughput.
 768
 769	  Select this if all CPUs need to be no-CBs CPUs for real-time
 770	  or energy-efficiency reasons.
 771
 772endchoice
 773
 774endmenu # "RCU Subsystem"
 775
 776config IKCONFIG
 777	tristate "Kernel .config support"
 778	---help---
 779	  This option enables the complete Linux kernel ".config" file
 780	  contents to be saved in the kernel. It provides documentation
 781	  of which kernel options are used in a running kernel or in an
 782	  on-disk kernel.  This information can be extracted from the kernel
 783	  image file with the script scripts/extract-ikconfig and used as
 784	  input to rebuild the current kernel or to build another kernel.
 785	  It can also be extracted from a running kernel by reading
 786	  /proc/config.gz if enabled (below).
 787
 788config IKCONFIG_PROC
 789	bool "Enable access to .config through /proc/config.gz"
 790	depends on IKCONFIG && PROC_FS
 791	---help---
 792	  This option enables access to the kernel configuration file
 793	  through /proc/config.gz.
 794
 795config LOG_BUF_SHIFT
 796	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 797	range 12 21
 798	default 17
 799	help
 800	  Select kernel log buffer size as a power of 2.
 801	  Examples:
 802	  	     17 => 128 KB
 803		     16 => 64 KB
 804	             15 => 32 KB
 805	             14 => 16 KB
 806		     13 =>  8 KB
 807		     12 =>  4 KB
 808
 809#
 810# Architectures with an unreliable sched_clock() should select this:
 811#
 812config HAVE_UNSTABLE_SCHED_CLOCK
 813	bool
 814
 815config GENERIC_SCHED_CLOCK
 816	bool
 817
 818#
 819# For architectures that want to enable the support for NUMA-affine scheduler
 820# balancing logic:
 821#
 822config ARCH_SUPPORTS_NUMA_BALANCING
 823	bool
 824
 825#
 826# For architectures that know their GCC __int128 support is sound
 827#
 828config ARCH_SUPPORTS_INT128
 829	bool
 830
 831# For architectures that (ab)use NUMA to represent different memory regions
 832# all cpu-local but of different latencies, such as SuperH.
 833#
 834config ARCH_WANT_NUMA_VARIABLE_LOCALITY
 835	bool
 836
 837#
 838# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
 839config ARCH_WANTS_PROT_NUMA_PROT_NONE
 840	bool
 841
 842config ARCH_USES_NUMA_PROT_NONE
 843	bool
 844	default y
 845	depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
 846	depends on NUMA_BALANCING
 847
 848config NUMA_BALANCING_DEFAULT_ENABLED
 849	bool "Automatically enable NUMA aware memory/task placement"
 850	default y
 851	depends on NUMA_BALANCING
 852	help
 853	  If set, automatic NUMA balancing will be enabled if running on a NUMA
 854	  machine.
 855
 856config NUMA_BALANCING
 857	bool "Memory placement aware NUMA scheduler"
 858	depends on ARCH_SUPPORTS_NUMA_BALANCING
 859	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
 860	depends on SMP && NUMA && MIGRATION
 861	help
 862	  This option adds support for automatic NUMA aware memory/task placement.
 863	  The mechanism is quite primitive and is based on migrating memory when
 864	  it has references to the node the task is running on.
 865
 866	  This system will be inactive on UMA systems.
 867
 868menuconfig CGROUPS
 869	boolean "Control Group support"
 870	select KERNFS
 871	help
 872	  This option adds support for grouping sets of processes together, for
 873	  use with process control subsystems such as Cpusets, CFS, memory
 874	  controls or device isolation.
 875	  See
 876		- Documentation/scheduler/sched-design-CFS.txt	(CFS)
 877		- Documentation/cgroups/ (features for grouping, isolation
 878					  and resource control)
 879
 880	  Say N if unsure.
 881
 882if CGROUPS
 883
 884config CGROUP_DEBUG
 885	bool "Example debug cgroup subsystem"
 886	default n
 887	help
 888	  This option enables a simple cgroup subsystem that
 889	  exports useful debugging information about the cgroups
 890	  framework.
 891
 892	  Say N if unsure.
 893
 894config CGROUP_FREEZER
 895	bool "Freezer cgroup subsystem"
 896	help
 897	  Provides a way to freeze and unfreeze all tasks in a
 898	  cgroup.
 899
 900config CGROUP_DEVICE
 901	bool "Device controller for cgroups"
 902	help
 903	  Provides a cgroup implementing whitelists for devices which
 904	  a process in the cgroup can mknod or open.
 905
 906config CPUSETS
 907	bool "Cpuset support"
 908	help
 909	  This option will let you create and manage CPUSETs which
 910	  allow dynamically partitioning a system into sets of CPUs and
 911	  Memory Nodes and assigning tasks to run only within those sets.
 912	  This is primarily useful on large SMP or NUMA systems.
 913
 914	  Say N if unsure.
 915
 916config PROC_PID_CPUSET
 917	bool "Include legacy /proc/<pid>/cpuset file"
 918	depends on CPUSETS
 919	default y
 920
 921config CGROUP_CPUACCT
 922	bool "Simple CPU accounting cgroup subsystem"
 923	help
 924	  Provides a simple Resource Controller for monitoring the
 925	  total CPU consumed by the tasks in a cgroup.
 926
 927config RESOURCE_COUNTERS
 928	bool "Resource counters"
 929	help
 930	  This option enables controller independent resource accounting
 931	  infrastructure that works with cgroups.
 932
 933config MEMCG
 934	bool "Memory Resource Controller for Control Groups"
 935	depends on RESOURCE_COUNTERS
 936	select MM_OWNER
 937	select EVENTFD
 938	help
 939	  Provides a memory resource controller that manages both anonymous
 940	  memory and page cache. (See Documentation/cgroups/memory.txt)
 941
 942	  Note that setting this option increases fixed memory overhead
 943	  associated with each page of memory in the system. By this,
 944	  8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 945	  usage tracking struct at boot. Total amount of this is printed out
 946	  at boot.
 947
 948	  Only enable when you're ok with these trade offs and really
 949	  sure you need the memory resource controller. Even when you enable
 950	  this, you can set "cgroup_disable=memory" at your boot option to
 951	  disable memory resource controller and you can avoid overheads.
 952	  (and lose benefits of memory resource controller)
 953
 954	  This config option also selects MM_OWNER config option, which
 955	  could in turn add some fork/exit overhead.
 956
 957config MEMCG_SWAP
 958	bool "Memory Resource Controller Swap Extension"
 959	depends on MEMCG && SWAP
 960	help
 961	  Add swap management feature to memory resource controller. When you
 962	  enable this, you can limit mem+swap usage per cgroup. In other words,
 963	  when you disable this, memory resource controller has no cares to
 964	  usage of swap...a process can exhaust all of the swap. This extension
 965	  is useful when you want to avoid exhaustion swap but this itself
 966	  adds more overheads and consumes memory for remembering information.
 967	  Especially if you use 32bit system or small memory system, please
 968	  be careful about enabling this. When memory resource controller
 969	  is disabled by boot option, this will be automatically disabled and
 970	  there will be no overhead from this. Even when you set this config=y,
 971	  if boot option "swapaccount=0" is set, swap will not be accounted.
 972	  Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 973	  size is 4096bytes, 512k per 1Gbytes of swap.
 974config MEMCG_SWAP_ENABLED
 975	bool "Memory Resource Controller Swap Extension enabled by default"
 976	depends on MEMCG_SWAP
 977	default y
 978	help
 979	  Memory Resource Controller Swap Extension comes with its price in
 980	  a bigger memory consumption. General purpose distribution kernels
 981	  which want to enable the feature but keep it disabled by default
 982	  and let the user enable it by swapaccount=1 boot command line
 983	  parameter should have this option unselected.
 984	  For those who want to have the feature enabled by default should
 985	  select this option (if, for some reason, they need to disable it
 986	  then swapaccount=0 does the trick).
 987config MEMCG_KMEM
 988	bool "Memory Resource Controller Kernel Memory accounting"
 989	depends on MEMCG
 990	depends on SLUB || SLAB
 991	help
 992	  The Kernel Memory extension for Memory Resource Controller can limit
 993	  the amount of memory used by kernel objects in the system. Those are
 994	  fundamentally different from the entities handled by the standard
 995	  Memory Controller, which are page-based, and can be swapped. Users of
 996	  the kmem extension can use it to guarantee that no group of processes
 997	  will ever exhaust kernel resources alone.
 998
 999config CGROUP_HUGETLB
1000	bool "HugeTLB Resource Controller for Control Groups"
1001	depends on RESOURCE_COUNTERS && HUGETLB_PAGE
1002	default n
1003	help
1004	  Provides a cgroup Resource Controller for HugeTLB pages.
1005	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
1006	  The limit is enforced during page fault. Since HugeTLB doesn't
1007	  support page reclaim, enforcing the limit at page fault time implies
1008	  that, the application will get SIGBUS signal if it tries to access
1009	  HugeTLB pages beyond its limit. This requires the application to know
1010	  beforehand how much HugeTLB pages it would require for its use. The
1011	  control group is tracked in the third page lru pointer. This means
1012	  that we cannot use the controller with huge page less than 3 pages.
1013
1014config CGROUP_PERF
1015	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
1016	depends on PERF_EVENTS && CGROUPS
1017	help
1018	  This option extends the per-cpu mode to restrict monitoring to
1019	  threads which belong to the cgroup specified and run on the
1020	  designated cpu.
1021
1022	  Say N if unsure.
1023
1024menuconfig CGROUP_SCHED
1025	bool "Group CPU scheduler"
 
1026	default n
1027	help
1028	  This feature lets CPU scheduler recognize task groups and control CPU
1029	  bandwidth allocation to such task groups. It uses cgroups to group
1030	  tasks.
1031
1032if CGROUP_SCHED
1033config FAIR_GROUP_SCHED
1034	bool "Group scheduling for SCHED_OTHER"
1035	depends on CGROUP_SCHED
1036	default CGROUP_SCHED
1037
1038config CFS_BANDWIDTH
1039	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1040	depends on FAIR_GROUP_SCHED
1041	default n
1042	help
1043	  This option allows users to define CPU bandwidth rates (limits) for
1044	  tasks running within the fair group scheduler.  Groups with no limit
1045	  set are considered to be unconstrained and will run with no
1046	  restriction.
1047	  See tip/Documentation/scheduler/sched-bwc.txt for more information.
1048
1049config RT_GROUP_SCHED
1050	bool "Group scheduling for SCHED_RR/FIFO"
 
1051	depends on CGROUP_SCHED
1052	default n
1053	help
1054	  This feature lets you explicitly allocate real CPU bandwidth
1055	  to task groups. If enabled, it will also make it impossible to
1056	  schedule realtime tasks for non-root users until you allocate
1057	  realtime bandwidth for them.
1058	  See Documentation/scheduler/sched-rt-group.txt for more information.
1059
1060endif #CGROUP_SCHED
1061
1062config BLK_CGROUP
1063	bool "Block IO controller"
1064	depends on BLOCK
1065	default n
1066	---help---
1067	Generic block IO controller cgroup interface. This is the common
1068	cgroup interface which should be used by various IO controlling
1069	policies.
1070
1071	Currently, CFQ IO scheduler uses it to recognize task groups and
1072	control disk bandwidth allocation (proportional time slice allocation)
1073	to such task groups. It is also used by bio throttling logic in
1074	block layer to implement upper limit in IO rates on a device.
1075
1076	This option only enables generic Block IO controller infrastructure.
1077	One needs to also enable actual IO controlling logic/policy. For
1078	enabling proportional weight division of disk bandwidth in CFQ, set
1079	CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1080	CONFIG_BLK_DEV_THROTTLING=y.
1081
1082	See Documentation/cgroups/blkio-controller.txt for more information.
1083
1084config DEBUG_BLK_CGROUP
1085	bool "Enable Block IO controller debugging"
1086	depends on BLK_CGROUP
1087	default n
1088	---help---
1089	Enable some debugging help. Currently it exports additional stat
1090	files in a cgroup which can be useful for debugging.
1091
1092endif # CGROUPS
1093
1094config CHECKPOINT_RESTORE
1095	bool "Checkpoint/restore support" if EXPERT
1096	default n
1097	help
1098	  Enables additional kernel features in a sake of checkpoint/restore.
1099	  In particular it adds auxiliary prctl codes to setup process text,
1100	  data and heap segment sizes, and a few additional /proc filesystem
1101	  entries.
1102
1103	  If unsure, say N here.
1104
1105menuconfig NAMESPACES
1106	bool "Namespaces support" if EXPERT
1107	default !EXPERT
1108	help
1109	  Provides the way to make tasks work with different objects using
1110	  the same id. For example same IPC id may refer to different objects
1111	  or same user id or pid may refer to different tasks when used in
1112	  different namespaces.
1113
1114if NAMESPACES
1115
1116config UTS_NS
1117	bool "UTS namespace"
1118	default y
1119	help
1120	  In this namespace tasks see different info provided with the
1121	  uname() system call
1122
1123config IPC_NS
1124	bool "IPC namespace"
1125	depends on (SYSVIPC || POSIX_MQUEUE)
1126	default y
1127	help
1128	  In this namespace tasks work with IPC ids which correspond to
1129	  different IPC objects in different namespaces.
1130
1131config USER_NS
1132	bool "User namespace"
1133	default n
 
1134	help
1135	  This allows containers, i.e. vservers, to use user namespaces
1136	  to provide different user info for different servers.
1137
1138	  When user namespaces are enabled in the kernel it is
1139	  recommended that the MEMCG and MEMCG_KMEM options also be
1140	  enabled and that user-space use the memory control groups to
1141	  limit the amount of memory a memory unprivileged users can
1142	  use.
1143
1144	  If unsure, say N.
1145
1146config PID_NS
1147	bool "PID Namespaces"
1148	default y
1149	help
1150	  Support process id namespaces.  This allows having multiple
1151	  processes with the same pid as long as they are in different
1152	  pid namespaces.  This is a building block of containers.
1153
1154config NET_NS
1155	bool "Network namespace"
1156	depends on NET
1157	default y
1158	help
1159	  Allow user space to create what appear to be multiple instances
1160	  of the network stack.
1161
1162endif # NAMESPACES
1163
1164config SCHED_AUTOGROUP
1165	bool "Automatic process group scheduling"
 
1166	select CGROUPS
1167	select CGROUP_SCHED
1168	select FAIR_GROUP_SCHED
1169	help
1170	  This option optimizes the scheduler for common desktop workloads by
1171	  automatically creating and populating task groups.  This separation
1172	  of workloads isolates aggressive CPU burners (like build jobs) from
1173	  desktop applications.  Task group autogeneration is currently based
1174	  upon task session.
1175
1176config MM_OWNER
1177	bool
1178
1179config SYSFS_DEPRECATED
1180	bool "Enable deprecated sysfs features to support old userspace tools"
1181	depends on SYSFS
1182	default n
1183	help
1184	  This option adds code that switches the layout of the "block" class
1185	  devices, to not show up in /sys/class/block/, but only in
1186	  /sys/block/.
1187
1188	  This switch is only active when the sysfs.deprecated=1 boot option is
1189	  passed or the SYSFS_DEPRECATED_V2 option is set.
1190
1191	  This option allows new kernels to run on old distributions and tools,
1192	  which might get confused by /sys/class/block/. Since 2007/2008 all
1193	  major distributions and tools handle this just fine.
1194
1195	  Recent distributions and userspace tools after 2009/2010 depend on
1196	  the existence of /sys/class/block/, and will not work with this
1197	  option enabled.
1198
1199	  Only if you are using a new kernel on an old distribution, you might
1200	  need to say Y here.
1201
1202config SYSFS_DEPRECATED_V2
1203	bool "Enable deprecated sysfs features by default"
1204	default n
1205	depends on SYSFS
1206	depends on SYSFS_DEPRECATED
1207	help
1208	  Enable deprecated sysfs by default.
1209
1210	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
1211	  option.
1212
1213	  Only if you are using a new kernel on an old distribution, you might
1214	  need to say Y here. Even then, odds are you would not need it
1215	  enabled, you can always pass the boot option if absolutely necessary.
1216
1217config RELAY
1218	bool "Kernel->user space relay support (formerly relayfs)"
1219	help
1220	  This option enables support for relay interface support in
1221	  certain file systems (such as debugfs).
1222	  It is designed to provide an efficient mechanism for tools and
1223	  facilities to relay large amounts of data from kernel space to
1224	  user space.
1225
1226	  If unsure, say N.
1227
1228config BLK_DEV_INITRD
1229	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1230	depends on BROKEN || !FRV
1231	help
1232	  The initial RAM filesystem is a ramfs which is loaded by the
1233	  boot loader (loadlin or lilo) and that is mounted as root
1234	  before the normal boot procedure. It is typically used to
1235	  load modules needed to mount the "real" root file system,
1236	  etc. See <file:Documentation/initrd.txt> for details.
1237
1238	  If RAM disk support (BLK_DEV_RAM) is also included, this
1239	  also enables initial RAM disk (initrd) support and adds
1240	  15 Kbytes (more on some other architectures) to the kernel size.
1241
1242	  If unsure say Y.
1243
1244if BLK_DEV_INITRD
1245
1246source "usr/Kconfig"
1247
1248endif
1249
1250config CC_OPTIMIZE_FOR_SIZE
1251	bool "Optimize for size"
1252	help
1253	  Enabling this option will pass "-Os" instead of "-O2" to gcc
1254	  resulting in a smaller kernel.
1255
1256	  If unsure, say N.
1257
1258config SYSCTL
1259	bool
1260
1261config ANON_INODES
1262	bool
1263
1264config HAVE_UID16
1265	bool
1266
1267config SYSCTL_EXCEPTION_TRACE
1268	bool
1269	help
1270	  Enable support for /proc/sys/debug/exception-trace.
1271
1272config SYSCTL_ARCH_UNALIGN_NO_WARN
1273	bool
1274	help
1275	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1276	  Allows arch to define/use @no_unaligned_warning to possibly warn
1277	  about unaligned access emulation going on under the hood.
1278
1279config SYSCTL_ARCH_UNALIGN_ALLOW
1280	bool
1281	help
1282	  Enable support for /proc/sys/kernel/unaligned-trap
1283	  Allows arches to define/use @unaligned_enabled to runtime toggle
1284	  the unaligned access emulation.
1285	  see arch/parisc/kernel/unaligned.c for reference
1286
1287config HAVE_PCSPKR_PLATFORM
1288	bool
1289
1290menuconfig EXPERT
1291	bool "Configure standard kernel features (expert users)"
1292	# Unhide debug options, to make the on-by-default options visible
1293	select DEBUG_KERNEL
1294	help
1295	  This option allows certain base kernel options and settings
1296          to be disabled or tweaked. This is for specialized
1297          environments which can tolerate a "non-standard" kernel.
1298          Only use this if you really know what you are doing.
1299
1300config UID16
1301	bool "Enable 16-bit UID system calls" if EXPERT
1302	depends on HAVE_UID16
1303	default y
1304	help
1305	  This enables the legacy 16-bit UID syscall wrappers.
1306
1307config SYSFS_SYSCALL
1308	bool "Sysfs syscall support" if EXPERT
1309	default y
1310	---help---
1311	  sys_sysfs is an obsolete system call no longer supported in libc.
1312	  Note that disabling this option is more secure but might break
1313	  compatibility with some systems.
1314
1315	  If unsure say Y here.
1316
1317config SYSCTL_SYSCALL
1318	bool "Sysctl syscall support" if EXPERT
1319	depends on PROC_SYSCTL
1320	default n
1321	select SYSCTL
1322	---help---
1323	  sys_sysctl uses binary paths that have been found challenging
1324	  to properly maintain and use.  The interface in /proc/sys
1325	  using paths with ascii names is now the primary path to this
1326	  information.
1327
1328	  Almost nothing using the binary sysctl interface so if you are
1329	  trying to save some space it is probably safe to disable this,
1330	  making your kernel marginally smaller.
1331
1332	  If unsure say N here.
1333
1334config KALLSYMS
1335	 bool "Load all symbols for debugging/ksymoops" if EXPERT
1336	 default y
1337	 help
1338	   Say Y here to let the kernel print out symbolic crash information and
1339	   symbolic stack backtraces. This increases the size of the kernel
1340	   somewhat, as all symbols have to be loaded into the kernel image.
1341
1342config KALLSYMS_ALL
1343	bool "Include all symbols in kallsyms"
1344	depends on DEBUG_KERNEL && KALLSYMS
1345	help
1346	   Normally kallsyms only contains the symbols of functions for nicer
1347	   OOPS messages and backtraces (i.e., symbols from the text and inittext
1348	   sections). This is sufficient for most cases. And only in very rare
1349	   cases (e.g., when a debugger is used) all symbols are required (e.g.,
1350	   names of variables from the data sections, etc).
1351
1352	   This option makes sure that all symbols are loaded into the kernel
1353	   image (i.e., symbols from all sections) in cost of increased kernel
1354	   size (depending on the kernel configuration, it may be 300KiB or
1355	   something like this).
1356
1357	   Say N unless you really need all symbols.
1358
 
 
 
 
 
 
 
 
 
1359config PRINTK
1360	default y
1361	bool "Enable support for printk" if EXPERT
1362	select IRQ_WORK
1363	help
1364	  This option enables normal printk support. Removing it
1365	  eliminates most of the message strings from the kernel image
1366	  and makes the kernel more or less silent. As this makes it
1367	  very difficult to diagnose system problems, saying N here is
1368	  strongly discouraged.
1369
1370config BUG
1371	bool "BUG() support" if EXPERT
1372	default y
1373	help
1374          Disabling this option eliminates support for BUG and WARN, reducing
1375          the size of your kernel image and potentially quietly ignoring
1376          numerous fatal conditions. You should only consider disabling this
1377          option for embedded systems with no facilities for reporting errors.
1378          Just say Y.
1379
1380config ELF_CORE
1381	depends on COREDUMP
1382	default y
1383	bool "Enable ELF core dumps" if EXPERT
1384	help
1385	  Enable support for generating core dumps. Disabling saves about 4k.
1386
1387
1388config PCSPKR_PLATFORM
1389	bool "Enable PC-Speaker support" if EXPERT
1390	depends on HAVE_PCSPKR_PLATFORM
1391	select I8253_LOCK
1392	default y
1393	help
1394          This option allows to disable the internal PC-Speaker
1395          support, saving some memory.
1396
 
 
 
1397config BASE_FULL
1398	default y
1399	bool "Enable full-sized data structures for core" if EXPERT
1400	help
1401	  Disabling this option reduces the size of miscellaneous core
1402	  kernel data structures. This saves memory on small machines,
1403	  but may reduce performance.
1404
1405config FUTEX
1406	bool "Enable futex support" if EXPERT
1407	default y
1408	select RT_MUTEXES
1409	help
1410	  Disabling this option will cause the kernel to be built without
1411	  support for "fast userspace mutexes".  The resulting kernel may not
1412	  run glibc-based applications correctly.
1413
1414config HAVE_FUTEX_CMPXCHG
1415	bool
1416	help
1417	  Architectures should select this if futex_atomic_cmpxchg_inatomic()
1418	  is implemented and always working. This removes a couple of runtime
1419	  checks.
1420
1421config EPOLL
1422	bool "Enable eventpoll support" if EXPERT
1423	default y
1424	select ANON_INODES
1425	help
1426	  Disabling this option will cause the kernel to be built without
1427	  support for epoll family of system calls.
1428
1429config SIGNALFD
1430	bool "Enable signalfd() system call" if EXPERT
1431	select ANON_INODES
1432	default y
1433	help
1434	  Enable the signalfd() system call that allows to receive signals
1435	  on a file descriptor.
1436
1437	  If unsure, say Y.
1438
1439config TIMERFD
1440	bool "Enable timerfd() system call" if EXPERT
1441	select ANON_INODES
1442	default y
1443	help
1444	  Enable the timerfd() system call that allows to receive timer
1445	  events on a file descriptor.
1446
1447	  If unsure, say Y.
1448
1449config EVENTFD
1450	bool "Enable eventfd() system call" if EXPERT
1451	select ANON_INODES
1452	default y
1453	help
1454	  Enable the eventfd() system call that allows to receive both
1455	  kernel notification (ie. KAIO) or userspace notifications.
1456
1457	  If unsure, say Y.
1458
1459config SHMEM
1460	bool "Use full shmem filesystem" if EXPERT
1461	default y
1462	depends on MMU
1463	help
1464	  The shmem is an internal filesystem used to manage shared memory.
1465	  It is backed by swap and manages resource limits. It is also exported
1466	  to userspace as tmpfs if TMPFS is enabled. Disabling this
1467	  option replaces shmem and tmpfs with the much simpler ramfs code,
1468	  which may be appropriate on small systems without swap.
1469
1470config AIO
1471	bool "Enable AIO support" if EXPERT
1472	default y
1473	help
1474	  This option enables POSIX asynchronous I/O which may by used
1475	  by some high performance threaded applications. Disabling
1476	  this option saves about 7k.
1477
1478config PCI_QUIRKS
1479	default y
1480	bool "Enable PCI quirk workarounds" if EXPERT
1481	depends on PCI
1482	help
1483	  This enables workarounds for various PCI chipset
1484	  bugs/quirks. Disable this only if your target machine is
1485	  unaffected by PCI quirks.
1486
1487config EMBEDDED
1488	bool "Embedded system"
1489	option allnoconfig_y
1490	select EXPERT
1491	help
1492	  This option should be enabled if compiling the kernel for
1493	  an embedded system so certain expert options are available
1494	  for configuration.
1495
1496config HAVE_PERF_EVENTS
1497	bool
1498	help
1499	  See tools/perf/design.txt for details.
1500
1501config PERF_USE_VMALLOC
1502	bool
1503	help
1504	  See tools/perf/design.txt for details
1505
1506menu "Kernel Performance Events And Counters"
1507
1508config PERF_EVENTS
1509	bool "Kernel performance events and counters"
1510	default y if PROFILING
1511	depends on HAVE_PERF_EVENTS
1512	select ANON_INODES
1513	select IRQ_WORK
1514	help
1515	  Enable kernel support for various performance events provided
1516	  by software and hardware.
1517
1518	  Software events are supported either built-in or via the
1519	  use of generic tracepoints.
1520
1521	  Most modern CPUs support performance events via performance
1522	  counter registers. These registers count the number of certain
1523	  types of hw events: such as instructions executed, cachemisses
1524	  suffered, or branches mis-predicted - without slowing down the
1525	  kernel or applications. These registers can also trigger interrupts
1526	  when a threshold number of events have passed - and can thus be
1527	  used to profile the code that runs on that CPU.
1528
1529	  The Linux Performance Event subsystem provides an abstraction of
1530	  these software and hardware event capabilities, available via a
1531	  system call and used by the "perf" utility in tools/perf/. It
1532	  provides per task and per CPU counters, and it provides event
1533	  capabilities on top of those.
1534
1535	  Say Y if unsure.
1536
 
 
 
 
 
 
 
 
 
 
 
 
1537config DEBUG_PERF_USE_VMALLOC
1538	default n
1539	bool "Debug: use vmalloc to back perf mmap() buffers"
1540	depends on PERF_EVENTS && DEBUG_KERNEL
1541	select PERF_USE_VMALLOC
1542	help
1543	 Use vmalloc memory to back perf mmap() buffers.
1544
1545	 Mostly useful for debugging the vmalloc code on platforms
1546	 that don't require it.
1547
1548	 Say N if unsure.
1549
1550endmenu
1551
1552config VM_EVENT_COUNTERS
1553	default y
1554	bool "Enable VM event counters for /proc/vmstat" if EXPERT
1555	help
1556	  VM event counters are needed for event counts to be shown.
1557	  This option allows the disabling of the VM event counters
1558	  on EXPERT systems.  /proc/vmstat will only show page counts
1559	  if VM event counters are disabled.
1560
 
 
 
 
 
 
 
 
 
1561config SLUB_DEBUG
1562	default y
1563	bool "Enable SLUB debugging support" if EXPERT
1564	depends on SLUB && SYSFS
1565	help
1566	  SLUB has extensive debug support features. Disabling these can
1567	  result in significant savings in code size. This also disables
1568	  SLUB sysfs support. /sys/slab will not exist and there will be
1569	  no support for cache validation etc.
1570
1571config COMPAT_BRK
1572	bool "Disable heap randomization"
1573	default y
1574	help
1575	  Randomizing heap placement makes heap exploits harder, but it
1576	  also breaks ancient binaries (including anything libc5 based).
1577	  This option changes the bootup default to heap randomization
1578	  disabled, and can be overridden at runtime by setting
1579	  /proc/sys/kernel/randomize_va_space to 2.
1580
1581	  On non-ancient distros (post-2000 ones) N is usually a safe choice.
1582
1583choice
1584	prompt "Choose SLAB allocator"
1585	default SLUB
1586	help
1587	   This option allows to select a slab allocator.
1588
1589config SLAB
1590	bool "SLAB"
1591	help
1592	  The regular slab allocator that is established and known to work
1593	  well in all environments. It organizes cache hot objects in
1594	  per cpu and per node queues.
1595
1596config SLUB
1597	bool "SLUB (Unqueued Allocator)"
1598	help
1599	   SLUB is a slab allocator that minimizes cache line usage
1600	   instead of managing queues of cached objects (SLAB approach).
1601	   Per cpu caching is realized using slabs of objects instead
1602	   of queues of objects. SLUB can use memory efficiently
1603	   and has enhanced diagnostics. SLUB is the default choice for
1604	   a slab allocator.
1605
1606config SLOB
1607	depends on EXPERT
1608	bool "SLOB (Simple Allocator)"
1609	help
1610	   SLOB replaces the stock allocator with a drastically simpler
1611	   allocator. SLOB is generally more space efficient but
1612	   does not perform as well on large systems.
1613
1614endchoice
1615
1616config SLUB_CPU_PARTIAL
1617	default y
1618	depends on SLUB && SMP
1619	bool "SLUB per cpu partial cache"
1620	help
1621	  Per cpu partial caches accellerate objects allocation and freeing
1622	  that is local to a processor at the price of more indeterminism
1623	  in the latency of the free. On overflow these caches will be cleared
1624	  which requires the taking of locks that may cause latency spikes.
1625	  Typically one would choose no for a realtime system.
1626
1627config MMAP_ALLOW_UNINITIALIZED
1628	bool "Allow mmapped anonymous memory to be uninitialized"
1629	depends on EXPERT && !MMU
1630	default n
1631	help
1632	  Normally, and according to the Linux spec, anonymous memory obtained
1633	  from mmap() has it's contents cleared before it is passed to
1634	  userspace.  Enabling this config option allows you to request that
1635	  mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1636	  providing a huge performance boost.  If this option is not enabled,
1637	  then the flag will be ignored.
1638
1639	  This is taken advantage of by uClibc's malloc(), and also by
1640	  ELF-FDPIC binfmt's brk and stack allocator.
1641
1642	  Because of the obvious security issues, this option should only be
1643	  enabled on embedded devices where you control what is run in
1644	  userspace.  Since that isn't generally a problem on no-MMU systems,
1645	  it is normally safe to say Y here.
1646
1647	  See Documentation/nommu-mmap.txt for more information.
1648
1649config SYSTEM_TRUSTED_KEYRING
1650	bool "Provide system-wide ring of trusted keys"
1651	depends on KEYS
1652	help
1653	  Provide a system keyring to which trusted keys can be added.  Keys in
1654	  the keyring are considered to be trusted.  Keys may be added at will
1655	  by the kernel from compiled-in data and from hardware key stores, but
1656	  userspace may only add extra keys if those keys can be verified by
1657	  keys already in the keyring.
1658
1659	  Keys in this keyring are used by module signature checking.
1660
1661config PROFILING
1662	bool "Profiling support"
1663	help
1664	  Say Y here to enable the extended profiling support mechanisms used
1665	  by profilers such as OProfile.
1666
1667#
1668# Place an empty function call at each tracepoint site. Can be
1669# dynamically changed for a probe function.
1670#
1671config TRACEPOINTS
1672	bool
1673
1674source "arch/Kconfig"
1675
1676endmenu		# General setup
1677
1678config HAVE_GENERIC_DMA_COHERENT
1679	bool
1680	default n
1681
1682config SLABINFO
1683	bool
1684	depends on PROC_FS
1685	depends on SLAB || SLUB_DEBUG
1686	default y
1687
1688config RT_MUTEXES
1689	boolean
1690
1691config BASE_SMALL
1692	int
1693	default 0 if BASE_FULL
1694	default 1 if !BASE_FULL
1695
1696menuconfig MODULES
1697	bool "Enable loadable module support"
1698	option modules
1699	help
1700	  Kernel modules are small pieces of compiled code which can
1701	  be inserted in the running kernel, rather than being
1702	  permanently built into the kernel.  You use the "modprobe"
1703	  tool to add (and sometimes remove) them.  If you say Y here,
1704	  many parts of the kernel can be built as modules (by
1705	  answering M instead of Y where indicated): this is most
1706	  useful for infrequently used options which are not required
1707	  for booting.  For more information, see the man pages for
1708	  modprobe, lsmod, modinfo, insmod and rmmod.
1709
1710	  If you say Y here, you will need to run "make
1711	  modules_install" to put the modules under /lib/modules/
1712	  where modprobe can find them (you may need to be root to do
1713	  this).
1714
1715	  If unsure, say Y.
1716
1717if MODULES
1718
1719config MODULE_FORCE_LOAD
1720	bool "Forced module loading"
1721	default n
1722	help
1723	  Allow loading of modules without version information (ie. modprobe
1724	  --force).  Forced module loading sets the 'F' (forced) taint flag and
1725	  is usually a really bad idea.
1726
1727config MODULE_UNLOAD
1728	bool "Module unloading"
1729	help
1730	  Without this option you will not be able to unload any
1731	  modules (note that some modules may not be unloadable
1732	  anyway), which makes your kernel smaller, faster
1733	  and simpler.  If unsure, say Y.
1734
1735config MODULE_FORCE_UNLOAD
1736	bool "Forced module unloading"
1737	depends on MODULE_UNLOAD
1738	help
1739	  This option allows you to force a module to unload, even if the
1740	  kernel believes it is unsafe: the kernel will remove the module
1741	  without waiting for anyone to stop using it (using the -f option to
1742	  rmmod).  This is mainly for kernel developers and desperate users.
1743	  If unsure, say N.
1744
1745config MODVERSIONS
1746	bool "Module versioning support"
1747	help
1748	  Usually, you have to use modules compiled with your kernel.
1749	  Saying Y here makes it sometimes possible to use modules
1750	  compiled for different kernels, by adding enough information
1751	  to the modules to (hopefully) spot any changes which would
1752	  make them incompatible with the kernel you are running.  If
1753	  unsure, say N.
1754
1755config MODULE_SRCVERSION_ALL
1756	bool "Source checksum for all modules"
1757	help
1758	  Modules which contain a MODULE_VERSION get an extra "srcversion"
1759	  field inserted into their modinfo section, which contains a
1760    	  sum of the source files which made it.  This helps maintainers
1761	  see exactly which source was used to build a module (since
1762	  others sometimes change the module source without updating
1763	  the version).  With this option, such a "srcversion" field
1764	  will be created for all modules.  If unsure, say N.
1765
1766config MODULE_SIG
1767	bool "Module signature verification"
1768	depends on MODULES
1769	select SYSTEM_TRUSTED_KEYRING
1770	select KEYS
1771	select CRYPTO
1772	select ASYMMETRIC_KEY_TYPE
1773	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1774	select PUBLIC_KEY_ALGO_RSA
1775	select ASN1
1776	select OID_REGISTRY
1777	select X509_CERTIFICATE_PARSER
1778	help
1779	  Check modules for valid signatures upon load: the signature
1780	  is simply appended to the module. For more information see
1781	  Documentation/module-signing.txt.
1782
1783	  !!!WARNING!!!  If you enable this option, you MUST make sure that the
1784	  module DOES NOT get stripped after being signed.  This includes the
1785	  debuginfo strip done by some packagers (such as rpmbuild) and
1786	  inclusion into an initramfs that wants the module size reduced.
1787
1788config MODULE_SIG_FORCE
1789	bool "Require modules to be validly signed"
1790	depends on MODULE_SIG
1791	help
1792	  Reject unsigned modules or signed modules for which we don't have a
1793	  key.  Without this, such modules will simply taint the kernel.
1794
1795config MODULE_SIG_ALL
1796	bool "Automatically sign all modules"
1797	default y
1798	depends on MODULE_SIG
1799	help
1800	  Sign all modules during make modules_install. Without this option,
1801	  modules must be signed manually, using the scripts/sign-file tool.
1802
1803comment "Do not forget to sign required modules with scripts/sign-file"
1804	depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1805
1806choice
1807	prompt "Which hash algorithm should modules be signed with?"
1808	depends on MODULE_SIG
1809	help
1810	  This determines which sort of hashing algorithm will be used during
1811	  signature generation.  This algorithm _must_ be built into the kernel
1812	  directly so that signature verification can take place.  It is not
1813	  possible to load a signed module containing the algorithm to check
1814	  the signature on that module.
1815
1816config MODULE_SIG_SHA1
1817	bool "Sign modules with SHA-1"
1818	select CRYPTO_SHA1
1819
1820config MODULE_SIG_SHA224
1821	bool "Sign modules with SHA-224"
1822	select CRYPTO_SHA256
1823
1824config MODULE_SIG_SHA256
1825	bool "Sign modules with SHA-256"
1826	select CRYPTO_SHA256
1827
1828config MODULE_SIG_SHA384
1829	bool "Sign modules with SHA-384"
1830	select CRYPTO_SHA512
1831
1832config MODULE_SIG_SHA512
1833	bool "Sign modules with SHA-512"
1834	select CRYPTO_SHA512
1835
1836endchoice
1837
1838config MODULE_SIG_HASH
1839	string
1840	depends on MODULE_SIG
1841	default "sha1" if MODULE_SIG_SHA1
1842	default "sha224" if MODULE_SIG_SHA224
1843	default "sha256" if MODULE_SIG_SHA256
1844	default "sha384" if MODULE_SIG_SHA384
1845	default "sha512" if MODULE_SIG_SHA512
1846
1847endif # MODULES
1848
1849config INIT_ALL_POSSIBLE
1850	bool
1851	help
1852	  Back when each arch used to define their own cpu_online_mask and
1853	  cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1854	  with all 1s, and others with all 0s.  When they were centralised,
1855	  it was better to provide this option than to break all the archs
1856	  and have several arch maintainers pursuing me down dark alleys.
1857
1858config STOP_MACHINE
1859	bool
1860	default y
1861	depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1862	help
1863	  Need stop_machine() primitive.
1864
1865source "block/Kconfig"
1866
1867config PREEMPT_NOTIFIERS
1868	bool
1869
1870config PADATA
1871	depends on SMP
1872	bool
1873
1874# Can be selected by architectures with broken toolchains
1875# that get confused by correct const<->read_only section
1876# mappings
1877config BROKEN_RODATA
1878	bool
1879
1880config ASN1
1881	tristate
1882	help
1883	  Build a simple ASN.1 grammar compiler that produces a bytecode output
1884	  that can be interpreted by the ASN.1 stream decoder and used to
1885	  inform it as to what tags are to be expected in a stream and what
1886	  functions to call on what tags.
1887
1888source "kernel/Kconfig.locks"