xref: /openbmc/linux/init/Kconfig (revision e11f0ae3)
180daa560SRoman Zippelconfig ARCH
280daa560SRoman Zippel	string
380daa560SRoman Zippel	option env="ARCH"
480daa560SRoman Zippel
580daa560SRoman Zippelconfig KERNELVERSION
680daa560SRoman Zippel	string
780daa560SRoman Zippel	option env="KERNELVERSION"
880daa560SRoman Zippel
9face4374SRoman Zippelconfig DEFCONFIG_LIST
10face4374SRoman Zippel	string
11b2670eacSPaolo 'Blaisorblade' Giarrusso	depends on !UML
12face4374SRoman Zippel	option defconfig_list
13face4374SRoman Zippel	default "/lib/modules/$UNAME_RELEASE/.config"
14face4374SRoman Zippel	default "/etc/kernel-config"
15face4374SRoman Zippel	default "/boot/config-$UNAME_RELEASE"
1673531905SSam Ravnborg	default "$ARCH_DEFCONFIG"
17face4374SRoman Zippel	default "arch/$ARCH/defconfig"
18face4374SRoman Zippel
19b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS
20b99b87f7SPeter Oberparleiter	bool
21b99b87f7SPeter Oberparleiter	depends on !UML
22b99b87f7SPeter Oberparleiter
23e360adbeSPeter Zijlstraconfig HAVE_IRQ_WORK
24e360adbeSPeter Zijlstra	bool
25e360adbeSPeter Zijlstra
26e360adbeSPeter Zijlstraconfig IRQ_WORK
27e360adbeSPeter Zijlstra	bool
28e360adbeSPeter Zijlstra	depends on HAVE_IRQ_WORK
29e360adbeSPeter Zijlstra
301dbdc6f1SDavid Daneyconfig BUILDTIME_EXTABLE_SORT
311dbdc6f1SDavid Daney	bool
321dbdc6f1SDavid Daney
33ff0cfc66SAl Boldimenu "General setup"
341da177e4SLinus Torvalds
351da177e4SLinus Torvaldsconfig EXPERIMENTAL
361da177e4SLinus Torvalds	bool "Prompt for development and/or incomplete code/drivers"
371da177e4SLinus Torvalds	---help---
381da177e4SLinus Torvalds	  Some of the various things that Linux supports (such as network
391da177e4SLinus Torvalds	  drivers, file systems, network protocols, etc.) can be in a state
401da177e4SLinus Torvalds	  of development where the functionality, stability, or the level of
411da177e4SLinus Torvalds	  testing is not yet high enough for general use. This is usually
421da177e4SLinus Torvalds	  known as the "alpha-test" phase among developers. If a feature is
431da177e4SLinus Torvalds	  currently in alpha-test, then the developers usually discourage
441da177e4SLinus Torvalds	  uninformed widespread use of this feature by the general public to
451da177e4SLinus Torvalds	  avoid "Why doesn't this work?" type mail messages. However, active
461da177e4SLinus Torvalds	  testing and use of these systems is welcomed. Just be aware that it
471da177e4SLinus Torvalds	  may not meet the normal level of reliability or it may fail to work
481da177e4SLinus Torvalds	  in some special cases. Detailed bug reports from people familiar
491da177e4SLinus Torvalds	  with the kernel internals are usually welcomed by the developers
501da177e4SLinus Torvalds	  (before submitting bug reports, please read the documents
511da177e4SLinus Torvalds	  <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
521da177e4SLinus Torvalds	  <file:Documentation/BUG-HUNTING>, and
531da177e4SLinus Torvalds	  <file:Documentation/oops-tracing.txt> in the kernel source).
541da177e4SLinus Torvalds
551da177e4SLinus Torvalds	  This option will also make obsoleted drivers available. These are
561da177e4SLinus Torvalds	  drivers that have been replaced by something else, and/or are
571da177e4SLinus Torvalds	  scheduled to be removed in a future kernel release.
581da177e4SLinus Torvalds
591da177e4SLinus Torvalds	  Unless you intend to help test and develop a feature or driver that
601da177e4SLinus Torvalds	  falls into this category, or you have a situation that requires
611da177e4SLinus Torvalds	  using these features, you should probably say N here, which will
621da177e4SLinus Torvalds	  cause the configurator to present you with fewer choices. If
631da177e4SLinus Torvalds	  you say Y here, you will be offered the choice of using features or
641da177e4SLinus Torvalds	  drivers that are currently considered to be in the alpha-test phase.
651da177e4SLinus Torvalds
661da177e4SLinus Torvaldsconfig BROKEN
671da177e4SLinus Torvalds	bool
681da177e4SLinus Torvalds
691da177e4SLinus Torvaldsconfig BROKEN_ON_SMP
701da177e4SLinus Torvalds	bool
711da177e4SLinus Torvalds	depends on BROKEN || !SMP
721da177e4SLinus Torvalds	default y
731da177e4SLinus Torvalds
741da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT
751da177e4SLinus Torvalds	int
76dd673bcaSAdrian Bunk	default 32 if !UML
77dd673bcaSAdrian Bunk	default 128 if UML
781da177e4SLinus Torvalds	help
7934ad92c2SRandy Dunlap	  Maximum of each of the number of arguments and environment
8034ad92c2SRandy Dunlap	  variables passed to init from the kernel command line.
811da177e4SLinus Torvalds
821da177e4SLinus Torvalds
8384336466SRoland McGrathconfig CROSS_COMPILE
8484336466SRoland McGrath	string "Cross-compiler tool prefix"
8584336466SRoland McGrath	help
8684336466SRoland McGrath	  Same as running 'make CROSS_COMPILE=prefix-' but stored for
8784336466SRoland McGrath	  default make runs in this kernel build directory.  You don't
8884336466SRoland McGrath	  need to set this unless you want the configured kernel build
8984336466SRoland McGrath	  directory to select the cross-compiler automatically.
9084336466SRoland McGrath
911da177e4SLinus Torvaldsconfig LOCALVERSION
921da177e4SLinus Torvalds	string "Local version - append to kernel release"
931da177e4SLinus Torvalds	help
941da177e4SLinus Torvalds	  Append an extra string to the end of your kernel version.
951da177e4SLinus Torvalds	  This will show up when you type uname, for example.
961da177e4SLinus Torvalds	  The string you set here will be appended after the contents of
971da177e4SLinus Torvalds	  any files with a filename matching localversion* in your
981da177e4SLinus Torvalds	  object and source tree, in that order.  Your total string can
991da177e4SLinus Torvalds	  be a maximum of 64 characters.
1001da177e4SLinus Torvalds
101aaebf433SRyan Andersonconfig LOCALVERSION_AUTO
102aaebf433SRyan Anderson	bool "Automatically append version information to the version string"
103aaebf433SRyan Anderson	default y
104aaebf433SRyan Anderson	help
105aaebf433SRyan Anderson	  This will try to automatically determine if the current tree is a
1066e5a5420SRobert P. J. Day	  release tree by looking for git tags that belong to the current
1076e5a5420SRobert P. J. Day	  top of tree revision.
108aaebf433SRyan Anderson
109aaebf433SRyan Anderson	  A string of the format -gxxxxxxxx will be added to the localversion
1106e5a5420SRobert P. J. Day	  if a git-based tree is found.  The string generated by this will be
111aaebf433SRyan Anderson	  appended after any matching localversion* files, and after the value
1126e5a5420SRobert P. J. Day	  set in CONFIG_LOCALVERSION.
113aaebf433SRyan Anderson
1146e5a5420SRobert P. J. Day	  (The actual string used here is the first eight characters produced
1156e5a5420SRobert P. J. Day	  by running the command:
1166e5a5420SRobert P. J. Day
1176e5a5420SRobert P. J. Day	    $ git rev-parse --verify HEAD
1186e5a5420SRobert P. J. Day
1196e5a5420SRobert P. J. Day	  which is done within the script "scripts/setlocalversion".)
120aaebf433SRyan Anderson
1212e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP
1222e9f3bddSH. Peter Anvin	bool
1232e9f3bddSH. Peter Anvin
1242e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2
1252e9f3bddSH. Peter Anvin	bool
1262e9f3bddSH. Peter Anvin
1272e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA
1282e9f3bddSH. Peter Anvin	bool
1292e9f3bddSH. Peter Anvin
1303ebe1243SLasse Collinconfig HAVE_KERNEL_XZ
1313ebe1243SLasse Collin	bool
1323ebe1243SLasse Collin
1337dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO
1347dd65febSAlbin Tonnerre	bool
1357dd65febSAlbin Tonnerre
13630d65dbfSAlain Knaffchoice
13730d65dbfSAlain Knaff	prompt "Kernel compression mode"
13830d65dbfSAlain Knaff	default KERNEL_GZIP
1393ebe1243SLasse Collin	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
14030d65dbfSAlain Knaff	help
14130d65dbfSAlain Knaff	  The linux kernel is a kind of self-extracting executable.
14230d65dbfSAlain Knaff	  Several compression algorithms are available, which differ
14330d65dbfSAlain Knaff	  in efficiency, compression and decompression speed.
14430d65dbfSAlain Knaff	  Compression speed is only relevant when building a kernel.
14530d65dbfSAlain Knaff	  Decompression speed is relevant at each boot.
14630d65dbfSAlain Knaff
14730d65dbfSAlain Knaff	  If you have any problems with bzip2 or lzma compressed
14830d65dbfSAlain Knaff	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
14930d65dbfSAlain Knaff	  version of this functionality (bzip2 only), for 2.4, was
15030d65dbfSAlain Knaff	  supplied by Christian Ludwig)
15130d65dbfSAlain Knaff
15230d65dbfSAlain Knaff	  High compression options are mostly useful for users, who
15330d65dbfSAlain Knaff	  are low on disk space (embedded systems), but for whom ram
15430d65dbfSAlain Knaff	  size matters less.
15530d65dbfSAlain Knaff
15630d65dbfSAlain Knaff	  If in doubt, select 'gzip'
15730d65dbfSAlain Knaff
15830d65dbfSAlain Knaffconfig KERNEL_GZIP
15930d65dbfSAlain Knaff	bool "Gzip"
1602e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_GZIP
16130d65dbfSAlain Knaff	help
1627dd65febSAlbin Tonnerre	  The old and tried gzip compression. It provides a good balance
1637dd65febSAlbin Tonnerre	  between compression ratio and decompression speed.
16430d65dbfSAlain Knaff
16530d65dbfSAlain Knaffconfig KERNEL_BZIP2
16630d65dbfSAlain Knaff	bool "Bzip2"
1672e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_BZIP2
16830d65dbfSAlain Knaff	help
16930d65dbfSAlain Knaff	  Its compression ratio and speed is intermediate.
1700a4dd35cSRandy Dunlap	  Decompression speed is slowest among the choices.  The kernel
1712e9f3bddSH. Peter Anvin	  size is about 10% smaller with bzip2, in comparison to gzip.
1722e9f3bddSH. Peter Anvin	  Bzip2 uses a large amount of memory. For modern kernels you
1732e9f3bddSH. Peter Anvin	  will need at least 8MB RAM or more for booting.
17430d65dbfSAlain Knaff
17530d65dbfSAlain Knaffconfig KERNEL_LZMA
17630d65dbfSAlain Knaff	bool "LZMA"
1772e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_LZMA
17830d65dbfSAlain Knaff	help
1790a4dd35cSRandy Dunlap	  This compression algorithm's ratio is best.  Decompression speed
1800a4dd35cSRandy Dunlap	  is between gzip and bzip2.  Compression is slowest.
1810a4dd35cSRandy Dunlap	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
18230d65dbfSAlain Knaff
1833ebe1243SLasse Collinconfig KERNEL_XZ
1843ebe1243SLasse Collin	bool "XZ"
1853ebe1243SLasse Collin	depends on HAVE_KERNEL_XZ
1863ebe1243SLasse Collin	help
1873ebe1243SLasse Collin	  XZ uses the LZMA2 algorithm and instruction set specific
1883ebe1243SLasse Collin	  BCJ filters which can improve compression ratio of executable
1893ebe1243SLasse Collin	  code. The size of the kernel is about 30% smaller with XZ in
1903ebe1243SLasse Collin	  comparison to gzip. On architectures for which there is a BCJ
1913ebe1243SLasse Collin	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
1923ebe1243SLasse Collin	  will create a few percent smaller kernel than plain LZMA.
1933ebe1243SLasse Collin
1943ebe1243SLasse Collin	  The speed is about the same as with LZMA: The decompression
1953ebe1243SLasse Collin	  speed of XZ is better than that of bzip2 but worse than gzip
1963ebe1243SLasse Collin	  and LZO. Compression is slow.
1973ebe1243SLasse Collin
1987dd65febSAlbin Tonnerreconfig KERNEL_LZO
1997dd65febSAlbin Tonnerre	bool "LZO"
2007dd65febSAlbin Tonnerre	depends on HAVE_KERNEL_LZO
2017dd65febSAlbin Tonnerre	help
2020a4dd35cSRandy Dunlap	  Its compression ratio is the poorest among the choices. The kernel
203681b3049SStephan Sperber	  size is about 10% bigger than gzip; however its speed
2047dd65febSAlbin Tonnerre	  (both compression and decompression) is the fastest.
2057dd65febSAlbin Tonnerre
20630d65dbfSAlain Knaffendchoice
20730d65dbfSAlain Knaff
208bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME
209bd5dc17bSJosh Triplett	string "Default hostname"
210bd5dc17bSJosh Triplett	default "(none)"
211bd5dc17bSJosh Triplett	help
212bd5dc17bSJosh Triplett	  This option determines the default system hostname before userspace
213bd5dc17bSJosh Triplett	  calls sethostname(2). The kernel traditionally uses "(none)" here,
214bd5dc17bSJosh Triplett	  but you may wish to use a different default here to make a minimal
215bd5dc17bSJosh Triplett	  system more usable with less configuration.
216bd5dc17bSJosh Triplett
2171da177e4SLinus Torvaldsconfig SWAP
2181da177e4SLinus Torvalds	bool "Support for paging of anonymous memory (swap)"
2199361401eSDavid Howells	depends on MMU && BLOCK
2201da177e4SLinus Torvalds	default y
2211da177e4SLinus Torvalds	help
2221da177e4SLinus Torvalds	  This option allows you to choose whether you want to have support
2231da177e4SLinus Torvalds	  for so called swap devices or swap files in your kernel that are
2241da177e4SLinus Torvalds	  used to provide more virtual memory than the actual RAM present
2251da177e4SLinus Torvalds	  in your computer.  If unsure say Y.
2261da177e4SLinus Torvalds
2271da177e4SLinus Torvaldsconfig SYSVIPC
2281da177e4SLinus Torvalds	bool "System V IPC"
2291da177e4SLinus Torvalds	---help---
2301da177e4SLinus Torvalds	  Inter Process Communication is a suite of library functions and
2311da177e4SLinus Torvalds	  system calls which let processes (running programs) synchronize and
2321da177e4SLinus Torvalds	  exchange information. It is generally considered to be a good thing,
2331da177e4SLinus Torvalds	  and some programs won't run unless you say Y here. In particular, if
2341da177e4SLinus Torvalds	  you want to run the DOS emulator dosemu under Linux (read the
2351da177e4SLinus Torvalds	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
2361da177e4SLinus Torvalds	  you'll need to say Y here.
2371da177e4SLinus Torvalds
2381da177e4SLinus Torvalds	  You can find documentation about IPC with "info ipc" and also in
2391da177e4SLinus Torvalds	  section 6.4 of the Linux Programmer's Guide, available from
2401da177e4SLinus Torvalds	  <http://www.tldp.org/guides.html>.
2411da177e4SLinus Torvalds
242a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL
243a5494dcdSEric W. Biederman	bool
244a5494dcdSEric W. Biederman	depends on SYSVIPC
245a5494dcdSEric W. Biederman	depends on SYSCTL
246a5494dcdSEric W. Biederman	default y
247a5494dcdSEric W. Biederman
2481da177e4SLinus Torvaldsconfig POSIX_MQUEUE
2491da177e4SLinus Torvalds	bool "POSIX Message Queues"
2501da177e4SLinus Torvalds	depends on NET && EXPERIMENTAL
2511da177e4SLinus Torvalds	---help---
2521da177e4SLinus Torvalds	  POSIX variant of message queues is a part of IPC. In POSIX message
2531da177e4SLinus Torvalds	  queues every message has a priority which decides about succession
2541da177e4SLinus Torvalds	  of receiving it by a process. If you want to compile and run
2551da177e4SLinus Torvalds	  programs written e.g. for Solaris with use of its POSIX message
256b0e37650SRobert P. J. Day	  queues (functions mq_*) say Y here.
2571da177e4SLinus Torvalds
2581da177e4SLinus Torvalds	  POSIX message queues are visible as a filesystem called 'mqueue'
2591da177e4SLinus Torvalds	  and can be mounted somewhere if you want to do filesystem
2601da177e4SLinus Torvalds	  operations on message queues.
2611da177e4SLinus Torvalds
2621da177e4SLinus Torvalds	  If unsure, say Y.
2631da177e4SLinus Torvalds
264bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL
265bdc8e5f8SSerge E. Hallyn	bool
266bdc8e5f8SSerge E. Hallyn	depends on POSIX_MQUEUE
267bdc8e5f8SSerge E. Hallyn	depends on SYSCTL
268bdc8e5f8SSerge E. Hallyn	default y
269bdc8e5f8SSerge E. Hallyn
270990d6c2dSAneesh Kumar K.Vconfig FHANDLE
271990d6c2dSAneesh Kumar K.V	bool "open by fhandle syscalls"
272990d6c2dSAneesh Kumar K.V	select EXPORTFS
273990d6c2dSAneesh Kumar K.V	help
274990d6c2dSAneesh Kumar K.V	  If you say Y here, a user level program will be able to map
275990d6c2dSAneesh Kumar K.V	  file names to handle and then later use the handle for
276990d6c2dSAneesh Kumar K.V	  different file system operations. This is useful in implementing
277990d6c2dSAneesh Kumar K.V	  userspace file servers, which now track files using handles instead
278990d6c2dSAneesh Kumar K.V	  of names. The handle would remain the same even if file names
279990d6c2dSAneesh Kumar K.V	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
280990d6c2dSAneesh Kumar K.V	  syscalls.
281990d6c2dSAneesh Kumar K.V
2821da177e4SLinus Torvaldsconfig AUDIT
2831da177e4SLinus Torvalds	bool "Auditing support"
284804a6a49SChris Wright	depends on NET
2851da177e4SLinus Torvalds	help
2861da177e4SLinus Torvalds	  Enable auditing infrastructure that can be used with another
2871da177e4SLinus Torvalds	  kernel subsystem, such as SELinux (which requires this for
2881da177e4SLinus Torvalds	  logging of avc messages output).  Does not do system-call
2891da177e4SLinus Torvalds	  auditing without CONFIG_AUDITSYSCALL.
2901da177e4SLinus Torvalds
2911da177e4SLinus Torvaldsconfig AUDITSYSCALL
2921da177e4SLinus Torvalds	bool "Enable system-call auditing support"
2938f827a14SWill Deacon	depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
2941da177e4SLinus Torvalds	default y if SECURITY_SELINUX
2951da177e4SLinus Torvalds	help
2961da177e4SLinus Torvalds	  Enable low-overhead system-call auditing infrastructure that
2971da177e4SLinus Torvalds	  can be used independently or with another kernel subsystem,
29867640b60SEric Paris	  such as SELinux.
2991da177e4SLinus Torvalds
300939a67fcSEric Parisconfig AUDIT_WATCH
301939a67fcSEric Paris	def_bool y
302939a67fcSEric Paris	depends on AUDITSYSCALL
303939a67fcSEric Paris	select FSNOTIFY
3041da177e4SLinus Torvalds
30574c3cbe3SAl Viroconfig AUDIT_TREE
30674c3cbe3SAl Viro	def_bool y
30763c882a0SEric Paris	depends on AUDITSYSCALL
30828a3a7ebSEric Paris	select FSNOTIFY
30974c3cbe3SAl Viro
310633b4545SEric Parisconfig AUDIT_LOGINUID_IMMUTABLE
311633b4545SEric Paris	bool "Make audit loginuid immutable"
312633b4545SEric Paris	depends on AUDIT
313633b4545SEric Paris	help
314f429ee3bSLinus Torvalds	  The config option toggles if a task setting its loginuid requires
315633b4545SEric Paris	  CAP_SYS_AUDITCONTROL or if that task should require no special permissions
316633b4545SEric Paris	  but should instead only allow setting its loginuid if it was never
317633b4545SEric Paris	  previously set.  On systems which use systemd or a similar central
318633b4545SEric Paris	  process to restart login services this should be set to true.  On older
319633b4545SEric Paris	  systems in which an admin would typically have to directly stop and
320633b4545SEric Paris	  start processes this should be set to false.  Setting this to true allows
321633b4545SEric Paris	  one to drop potentially dangerous capabilites from the login tasks,
322633b4545SEric Paris	  but may not be backwards compatible with older init systems.
323633b4545SEric Paris
324d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig"
325764e0da1SThomas Gleixnersource "kernel/time/Kconfig"
326d9817ebeSThomas Gleixner
327391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting"
328391dc69cSFrederic Weisbecker
329fdf9c356SFrederic Weisbeckerchoice
330fdf9c356SFrederic Weisbecker	prompt "Cputime accounting"
331fdf9c356SFrederic Weisbecker	default TICK_CPU_ACCOUNTING if !PPC64
332fdf9c356SFrederic Weisbecker	default VIRT_CPU_ACCOUNTING if PPC64
333fdf9c356SFrederic Weisbecker
334fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting
335fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING
336fdf9c356SFrederic Weisbecker	bool "Simple tick based cputime accounting"
337fdf9c356SFrederic Weisbecker	depends on !S390
338fdf9c356SFrederic Weisbecker	help
339fdf9c356SFrederic Weisbecker	  This is the basic tick based cputime accounting that maintains
340fdf9c356SFrederic Weisbecker	  statistics about user, system and idle time spent on per jiffies
341fdf9c356SFrederic Weisbecker	  granularity.
342fdf9c356SFrederic Weisbecker
343fdf9c356SFrederic Weisbecker	  If unsure, say Y.
344fdf9c356SFrederic Weisbecker
345391dc69cSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING
346391dc69cSFrederic Weisbecker	bool "Deterministic task and CPU time accounting"
347391dc69cSFrederic Weisbecker	depends on HAVE_VIRT_CPU_ACCOUNTING
348391dc69cSFrederic Weisbecker	help
349391dc69cSFrederic Weisbecker	  Select this option to enable more accurate task and CPU time
350391dc69cSFrederic Weisbecker	  accounting.  This is done by reading a CPU counter on each
351391dc69cSFrederic Weisbecker	  kernel entry and exit and on transitions within the kernel
352391dc69cSFrederic Weisbecker	  between system, softirq and hardirq state, so there is a
353391dc69cSFrederic Weisbecker	  small performance impact.  In the case of s390 or IBM POWER > 5,
354391dc69cSFrederic Weisbecker	  this also enables accounting of stolen time on logically-partitioned
355391dc69cSFrederic Weisbecker	  systems.
356391dc69cSFrederic Weisbecker
357fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING
358fdf9c356SFrederic Weisbecker	bool "Fine granularity task level IRQ time accounting"
359fdf9c356SFrederic Weisbecker	depends on HAVE_IRQ_TIME_ACCOUNTING
360fdf9c356SFrederic Weisbecker	help
361fdf9c356SFrederic Weisbecker	  Select this option to enable fine granularity task irq time
362fdf9c356SFrederic Weisbecker	  accounting. This is done by reading a timestamp on each
363fdf9c356SFrederic Weisbecker	  transitions between softirq and hardirq state, so there can be a
364fdf9c356SFrederic Weisbecker	  small performance impact.
365fdf9c356SFrederic Weisbecker
366fdf9c356SFrederic Weisbecker	  If in doubt, say N here.
367fdf9c356SFrederic Weisbecker
368fdf9c356SFrederic Weisbeckerendchoice
369fdf9c356SFrederic Weisbecker
370391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT
371391dc69cSFrederic Weisbecker	bool "BSD Process Accounting"
372391dc69cSFrederic Weisbecker	help
373391dc69cSFrederic Weisbecker	  If you say Y here, a user level program will be able to instruct the
374391dc69cSFrederic Weisbecker	  kernel (via a special system call) to write process accounting
375391dc69cSFrederic Weisbecker	  information to a file: whenever a process exits, information about
376391dc69cSFrederic Weisbecker	  that process will be appended to the file by the kernel.  The
377391dc69cSFrederic Weisbecker	  information includes things such as creation time, owning user,
378391dc69cSFrederic Weisbecker	  command name, memory usage, controlling terminal etc. (the complete
379391dc69cSFrederic Weisbecker	  list is in the struct acct in <file:include/linux/acct.h>).  It is
380391dc69cSFrederic Weisbecker	  up to the user level program to do useful things with this
381391dc69cSFrederic Weisbecker	  information.  This is generally a good idea, so say Y.
382391dc69cSFrederic Weisbecker
383391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3
384391dc69cSFrederic Weisbecker	bool "BSD Process Accounting version 3 file format"
385391dc69cSFrederic Weisbecker	depends on BSD_PROCESS_ACCT
386391dc69cSFrederic Weisbecker	default n
387391dc69cSFrederic Weisbecker	help
388391dc69cSFrederic Weisbecker	  If you say Y here, the process accounting information is written
389391dc69cSFrederic Weisbecker	  in a new file format that also logs the process IDs of each
390391dc69cSFrederic Weisbecker	  process and it's parent. Note that this file format is incompatible
391391dc69cSFrederic Weisbecker	  with previous v0/v1/v2 file formats, so you will need updated tools
392391dc69cSFrederic Weisbecker	  for processing it. A preliminary version of these tools is available
393391dc69cSFrederic Weisbecker	  at <http://www.gnu.org/software/acct/>.
394391dc69cSFrederic Weisbecker
395391dc69cSFrederic Weisbeckerconfig TASKSTATS
396391dc69cSFrederic Weisbecker	bool "Export task/process statistics through netlink (EXPERIMENTAL)"
397391dc69cSFrederic Weisbecker	depends on NET
398391dc69cSFrederic Weisbecker	default n
399391dc69cSFrederic Weisbecker	help
400391dc69cSFrederic Weisbecker	  Export selected statistics for tasks/processes through the
401391dc69cSFrederic Weisbecker	  generic netlink interface. Unlike BSD process accounting, the
402391dc69cSFrederic Weisbecker	  statistics are available during the lifetime of tasks/processes as
403391dc69cSFrederic Weisbecker	  responses to commands. Like BSD accounting, they are sent to user
404391dc69cSFrederic Weisbecker	  space on task exit.
405391dc69cSFrederic Weisbecker
406391dc69cSFrederic Weisbecker	  Say N if unsure.
407391dc69cSFrederic Weisbecker
408391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT
409391dc69cSFrederic Weisbecker	bool "Enable per-task delay accounting (EXPERIMENTAL)"
410391dc69cSFrederic Weisbecker	depends on TASKSTATS
411391dc69cSFrederic Weisbecker	help
412391dc69cSFrederic Weisbecker	  Collect information on time spent by a task waiting for system
413391dc69cSFrederic Weisbecker	  resources like cpu, synchronous block I/O completion and swapping
414391dc69cSFrederic Weisbecker	  in pages. Such statistics can help in setting a task's priorities
415391dc69cSFrederic Weisbecker	  relative to other tasks for cpu, io, rss limits etc.
416391dc69cSFrederic Weisbecker
417391dc69cSFrederic Weisbecker	  Say N if unsure.
418391dc69cSFrederic Weisbecker
419391dc69cSFrederic Weisbeckerconfig TASK_XACCT
420391dc69cSFrederic Weisbecker	bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
421391dc69cSFrederic Weisbecker	depends on TASKSTATS
422391dc69cSFrederic Weisbecker	help
423391dc69cSFrederic Weisbecker	  Collect extended task accounting data and send the data
424391dc69cSFrederic Weisbecker	  to userland for processing over the taskstats interface.
425391dc69cSFrederic Weisbecker
426391dc69cSFrederic Weisbecker	  Say N if unsure.
427391dc69cSFrederic Weisbecker
428391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING
429391dc69cSFrederic Weisbecker	bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
430391dc69cSFrederic Weisbecker	depends on TASK_XACCT
431391dc69cSFrederic Weisbecker	help
432391dc69cSFrederic Weisbecker	  Collect information on the number of bytes of storage I/O which this
433391dc69cSFrederic Weisbecker	  task has caused.
434391dc69cSFrederic Weisbecker
435391dc69cSFrederic Weisbecker	  Say N if unsure.
436391dc69cSFrederic Weisbecker
437391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting"
438391dc69cSFrederic Weisbecker
439c903ff83SMike Travismenu "RCU Subsystem"
440c903ff83SMike Travis
441c903ff83SMike Travischoice
442c903ff83SMike Travis	prompt "RCU Implementation"
44331c9a24eSPaul E. McKenney	default TREE_RCU
444c903ff83SMike Travis
445c903ff83SMike Travisconfig TREE_RCU
446c903ff83SMike Travis	bool "Tree-based hierarchical RCU"
447687d7a96SPaul E. McKenney	depends on !PREEMPT && SMP
448c903ff83SMike Travis	help
449c903ff83SMike Travis	  This option selects the RCU implementation that is
450c903ff83SMike Travis	  designed for very large SMP system with hundreds or
451c17ef453SPaul E. McKenney	  thousands of CPUs.  It also scales down nicely to
452c17ef453SPaul E. McKenney	  smaller systems.
453c903ff83SMike Travis
454f41d911fSPaul E. McKenneyconfig TREE_PREEMPT_RCU
455a57eb940SPaul E. McKenney	bool "Preemptible tree-based hierarchical RCU"
4568008e129SPaul E. McKenney	depends on PREEMPT && SMP
457f41d911fSPaul E. McKenney	help
458f41d911fSPaul E. McKenney	  This option selects the RCU implementation that is
459f41d911fSPaul E. McKenney	  designed for very large SMP systems with hundreds or
460f41d911fSPaul E. McKenney	  thousands of CPUs, but for which real-time response
461bbe3eae8SPaul E. McKenney	  is also required.  It also scales down nicely to
462bbe3eae8SPaul E. McKenney	  smaller systems.
463f41d911fSPaul E. McKenney
4649b1d82faSPaul E. McKenneyconfig TINY_RCU
4659b1d82faSPaul E. McKenney	bool "UP-only small-memory-footprint RCU"
4668008e129SPaul E. McKenney	depends on !PREEMPT && !SMP
4679b1d82faSPaul E. McKenney	help
4689b1d82faSPaul E. McKenney	  This option selects the RCU implementation that is
4699b1d82faSPaul E. McKenney	  designed for UP systems from which real-time response
4709b1d82faSPaul E. McKenney	  is not required.  This option greatly reduces the
4719b1d82faSPaul E. McKenney	  memory footprint of RCU.
4729b1d82faSPaul E. McKenney
473a57eb940SPaul E. McKenneyconfig TINY_PREEMPT_RCU
474a57eb940SPaul E. McKenney	bool "Preemptible UP-only small-memory-footprint RCU"
4758008e129SPaul E. McKenney	depends on PREEMPT && !SMP
476a57eb940SPaul E. McKenney	help
477a57eb940SPaul E. McKenney	  This option selects the RCU implementation that is designed
478a57eb940SPaul E. McKenney	  for real-time UP systems.  This option greatly reduces the
479a57eb940SPaul E. McKenney	  memory footprint of RCU.
480a57eb940SPaul E. McKenney
481c903ff83SMike Travisendchoice
482c903ff83SMike Travis
483a57eb940SPaul E. McKenneyconfig PREEMPT_RCU
484a57eb940SPaul E. McKenney	def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
485a57eb940SPaul E. McKenney	help
486a57eb940SPaul E. McKenney	  This option enables preemptible-RCU code that is common between
487a57eb940SPaul E. McKenney	  the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
488a57eb940SPaul E. McKenney
48991d1aa43SFrederic Weisbeckerconfig CONTEXT_TRACKING
49091d1aa43SFrederic Weisbecker       bool
49191d1aa43SFrederic Weisbecker
4922b1d5024SFrederic Weisbeckerconfig RCU_USER_QS
4932b1d5024SFrederic Weisbecker	bool "Consider userspace as in RCU extended quiescent state"
49491d1aa43SFrederic Weisbecker	depends on HAVE_CONTEXT_TRACKING && SMP
49591d1aa43SFrederic Weisbecker	select CONTEXT_TRACKING
4962b1d5024SFrederic Weisbecker	help
4972b1d5024SFrederic Weisbecker	  This option sets hooks on kernel / userspace boundaries and
4982b1d5024SFrederic Weisbecker	  puts RCU in extended quiescent state when the CPU runs in
4992b1d5024SFrederic Weisbecker	  userspace. It means that when a CPU runs in userspace, it is
5002b1d5024SFrederic Weisbecker	  excluded from the global RCU state machine and thus doesn't
501af71befaSPaul Gortmaker	  try to keep the timer tick on for RCU.
5022b1d5024SFrederic Weisbecker
503d677124bSFrederic Weisbecker	  Unless you want to hack and help the development of the full
50491d1aa43SFrederic Weisbecker	  dynticks mode, you shouldn't enable this option.  It also
505af71befaSPaul Gortmaker	  adds unnecessary overhead.
506d677124bSFrederic Weisbecker
507d677124bSFrederic Weisbecker	  If unsure say N
508d677124bSFrederic Weisbecker
50991d1aa43SFrederic Weisbeckerconfig CONTEXT_TRACKING_FORCE
51091d1aa43SFrederic Weisbecker	bool "Force context tracking"
51191d1aa43SFrederic Weisbecker	depends on CONTEXT_TRACKING
5121fd2b442SFrederic Weisbecker	help
51391d1aa43SFrederic Weisbecker	  Probe on user/kernel boundaries by default in order to
51491d1aa43SFrederic Weisbecker	  test the features that rely on it such as userspace RCU extended
51591d1aa43SFrederic Weisbecker	  quiescent states.
51691d1aa43SFrederic Weisbecker	  This test is there for debugging until we have a real user like the
51791d1aa43SFrederic Weisbecker	  full dynticks mode.
518d677124bSFrederic Weisbecker
519c903ff83SMike Travisconfig RCU_FANOUT
520c903ff83SMike Travis	int "Tree-based hierarchical RCU fanout value"
521c903ff83SMike Travis	range 2 64 if 64BIT
522c903ff83SMike Travis	range 2 32 if !64BIT
523f41d911fSPaul E. McKenney	depends on TREE_RCU || TREE_PREEMPT_RCU
524c903ff83SMike Travis	default 64 if 64BIT
525c903ff83SMike Travis	default 32 if !64BIT
526c903ff83SMike Travis	help
527c903ff83SMike Travis	  This option controls the fanout of hierarchical implementations
528c903ff83SMike Travis	  of RCU, allowing RCU to work efficiently on machines with
5294d87ffadSPaul E. McKenney	  large numbers of CPUs.  This value must be at least the fourth
5304d87ffadSPaul E. McKenney	  root of NR_CPUS, which allows NR_CPUS to be insanely large.
5314d87ffadSPaul E. McKenney	  The default value of RCU_FANOUT should be used for production
5324d87ffadSPaul E. McKenney	  systems, but if you are stress-testing the RCU implementation
5334d87ffadSPaul E. McKenney	  itself, small RCU_FANOUT values allow you to test large-system
5344d87ffadSPaul E. McKenney	  code paths on small(er) systems.
535c903ff83SMike Travis
536c903ff83SMike Travis	  Select a specific number if testing RCU itself.
537c903ff83SMike Travis	  Take the default if unsure.
538c903ff83SMike Travis
5398932a63dSPaul E. McKenneyconfig RCU_FANOUT_LEAF
5408932a63dSPaul E. McKenney	int "Tree-based hierarchical RCU leaf-level fanout value"
5418932a63dSPaul E. McKenney	range 2 RCU_FANOUT if 64BIT
5428932a63dSPaul E. McKenney	range 2 RCU_FANOUT if !64BIT
5438932a63dSPaul E. McKenney	depends on TREE_RCU || TREE_PREEMPT_RCU
5448932a63dSPaul E. McKenney	default 16
5458932a63dSPaul E. McKenney	help
5468932a63dSPaul E. McKenney	  This option controls the leaf-level fanout of hierarchical
5478932a63dSPaul E. McKenney	  implementations of RCU, and allows trading off cache misses
5488932a63dSPaul E. McKenney	  against lock contention.  Systems that synchronize their
5498932a63dSPaul E. McKenney	  scheduling-clock interrupts for energy-efficiency reasons will
5508932a63dSPaul E. McKenney	  want the default because the smaller leaf-level fanout keeps
5518932a63dSPaul E. McKenney	  lock contention levels acceptably low.  Very large systems
5528932a63dSPaul E. McKenney	  (hundreds or thousands of CPUs) will instead want to set this
5538932a63dSPaul E. McKenney	  value to the maximum value possible in order to reduce the
5548932a63dSPaul E. McKenney	  number of cache misses incurred during RCU's grace-period
5558932a63dSPaul E. McKenney	  initialization.  These systems tend to run CPU-bound, and thus
5568932a63dSPaul E. McKenney	  are not helped by synchronized interrupts, and thus tend to
5578932a63dSPaul E. McKenney	  skew them, which reduces lock contention enough that large
5588932a63dSPaul E. McKenney	  leaf-level fanouts work well.
5598932a63dSPaul E. McKenney
5608932a63dSPaul E. McKenney	  Select a specific number if testing RCU itself.
5618932a63dSPaul E. McKenney
5628932a63dSPaul E. McKenney	  Select the maximum permissible value for large systems.
5638932a63dSPaul E. McKenney
5648932a63dSPaul E. McKenney	  Take the default if unsure.
5658932a63dSPaul E. McKenney
566c903ff83SMike Travisconfig RCU_FANOUT_EXACT
567c903ff83SMike Travis	bool "Disable tree-based hierarchical RCU auto-balancing"
568f41d911fSPaul E. McKenney	depends on TREE_RCU || TREE_PREEMPT_RCU
569c903ff83SMike Travis	default n
570c903ff83SMike Travis	help
571c903ff83SMike Travis	  This option forces use of the exact RCU_FANOUT value specified,
572c903ff83SMike Travis	  regardless of imbalances in the hierarchy.  This is useful for
573c903ff83SMike Travis	  testing RCU itself, and might one day be useful on systems with
574c903ff83SMike Travis	  strong NUMA behavior.
575c903ff83SMike Travis
576c903ff83SMike Travis	  Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
577c903ff83SMike Travis
578c903ff83SMike Travis	  Say N if unsure.
579c903ff83SMike Travis
5808bd93a2cSPaul E. McKenneyconfig RCU_FAST_NO_HZ
5818bd93a2cSPaul E. McKenney	bool "Accelerate last non-dyntick-idle CPU's grace periods"
582b807fbffSPaul E. McKenney	depends on NO_HZ && SMP
5838bd93a2cSPaul E. McKenney	default n
5848bd93a2cSPaul E. McKenney	help
585ba49df47SPaul E. McKenney	  This option causes RCU to attempt to accelerate grace periods in
586ba49df47SPaul E. McKenney	  order to allow CPUs to enter dynticks-idle state more quickly.
587ba49df47SPaul E. McKenney	  On the other hand, this option increases the overhead of the
588ba49df47SPaul E. McKenney	  dynticks-idle checking, thus degrading scheduling latency.
5898bd93a2cSPaul E. McKenney
590ba49df47SPaul E. McKenney	  Say Y if energy efficiency is critically important, and you don't
591ba49df47SPaul E. McKenney	  	care about real-time response.
5928bd93a2cSPaul E. McKenney
5938bd93a2cSPaul E. McKenney	  Say N if you are unsure.
5948bd93a2cSPaul E. McKenney
595c903ff83SMike Travisconfig TREE_RCU_TRACE
596f41d911fSPaul E. McKenney	def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
597c903ff83SMike Travis	select DEBUG_FS
598c903ff83SMike Travis	help
599f41d911fSPaul E. McKenney	  This option provides tracing for the TREE_RCU and
600f41d911fSPaul E. McKenney	  TREE_PREEMPT_RCU implementations, permitting Makefile to
601f41d911fSPaul E. McKenney	  trivially select kernel/rcutree_trace.c.
602c903ff83SMike Travis
60324278d14SPaul E. McKenneyconfig RCU_BOOST
60424278d14SPaul E. McKenney	bool "Enable RCU priority boosting"
60527f4d280SPaul E. McKenney	depends on RT_MUTEXES && PREEMPT_RCU
60624278d14SPaul E. McKenney	default n
60724278d14SPaul E. McKenney	help
60824278d14SPaul E. McKenney	  This option boosts the priority of preempted RCU readers that
60924278d14SPaul E. McKenney	  block the current preemptible RCU grace period for too long.
61024278d14SPaul E. McKenney	  This option also prevents heavy loads from blocking RCU
61124278d14SPaul E. McKenney	  callback invocation for all flavors of RCU.
61224278d14SPaul E. McKenney
61324278d14SPaul E. McKenney	  Say Y here if you are working with real-time apps or heavy loads
61424278d14SPaul E. McKenney	  Say N here if you are unsure.
61524278d14SPaul E. McKenney
61624278d14SPaul E. McKenneyconfig RCU_BOOST_PRIO
61724278d14SPaul E. McKenney	int "Real-time priority to boost RCU readers to"
61824278d14SPaul E. McKenney	range 1 99
61924278d14SPaul E. McKenney	depends on RCU_BOOST
62024278d14SPaul E. McKenney	default 1
62124278d14SPaul E. McKenney	help
622c9336643SPaul E. McKenney	  This option specifies the real-time priority to which long-term
623c9336643SPaul E. McKenney	  preempted RCU readers are to be boosted.  If you are working
624c9336643SPaul E. McKenney	  with a real-time application that has one or more CPU-bound
625c9336643SPaul E. McKenney	  threads running at a real-time priority level, you should set
626c9336643SPaul E. McKenney	  RCU_BOOST_PRIO to a priority higher then the highest-priority
627c9336643SPaul E. McKenney	  real-time CPU-bound thread.  The default RCU_BOOST_PRIO value
628c9336643SPaul E. McKenney	  of 1 is appropriate in the common case, which is real-time
629c9336643SPaul E. McKenney	  applications that do not have any CPU-bound threads.
630c9336643SPaul E. McKenney
631c9336643SPaul E. McKenney	  Some real-time applications might not have a single real-time
632c9336643SPaul E. McKenney	  thread that saturates a given CPU, but instead might have
633c9336643SPaul E. McKenney	  multiple real-time threads that, taken together, fully utilize
634c9336643SPaul E. McKenney	  that CPU.  In this case, you should set RCU_BOOST_PRIO to
635c9336643SPaul E. McKenney	  a priority higher than the lowest-priority thread that is
636c9336643SPaul E. McKenney	  conspiring to prevent the CPU from running any non-real-time
637c9336643SPaul E. McKenney	  tasks.  For example, if one thread at priority 10 and another
638c9336643SPaul E. McKenney	  thread at priority 5 are between themselves fully consuming
639c9336643SPaul E. McKenney	  the CPU time on a given CPU, then RCU_BOOST_PRIO should be
640c9336643SPaul E. McKenney	  set to priority 6 or higher.
64124278d14SPaul E. McKenney
64224278d14SPaul E. McKenney	  Specify the real-time priority, or take the default if unsure.
64324278d14SPaul E. McKenney
64424278d14SPaul E. McKenneyconfig RCU_BOOST_DELAY
64524278d14SPaul E. McKenney	int "Milliseconds to delay boosting after RCU grace-period start"
64624278d14SPaul E. McKenney	range 0 3000
64724278d14SPaul E. McKenney	depends on RCU_BOOST
64824278d14SPaul E. McKenney	default 500
64924278d14SPaul E. McKenney	help
65024278d14SPaul E. McKenney	  This option specifies the time to wait after the beginning of
65124278d14SPaul E. McKenney	  a given grace period before priority-boosting preempted RCU
65224278d14SPaul E. McKenney	  readers blocking that grace period.  Note that any RCU reader
65324278d14SPaul E. McKenney	  blocking an expedited RCU grace period is boosted immediately.
65424278d14SPaul E. McKenney
65524278d14SPaul E. McKenney	  Accept the default if unsure.
65624278d14SPaul E. McKenney
6573fbfbf7aSPaul E. McKenneyconfig RCU_NOCB_CPU
6583fbfbf7aSPaul E. McKenney	bool "Offload RCU callback processing from boot-selected CPUs"
6593fbfbf7aSPaul E. McKenney	depends on TREE_RCU || TREE_PREEMPT_RCU
6603fbfbf7aSPaul E. McKenney	default n
6613fbfbf7aSPaul E. McKenney	help
6623fbfbf7aSPaul E. McKenney	  Use this option to reduce OS jitter for aggressive HPC or
6633fbfbf7aSPaul E. McKenney	  real-time workloads.	It can also be used to offload RCU
6643fbfbf7aSPaul E. McKenney	  callback invocation to energy-efficient CPUs in battery-powered
6653fbfbf7aSPaul E. McKenney	  asymmetric multiprocessors.
6663fbfbf7aSPaul E. McKenney
6673fbfbf7aSPaul E. McKenney	  This option offloads callback invocation from the set of
6683fbfbf7aSPaul E. McKenney	  CPUs specified at boot time by the rcu_nocbs parameter.
6693fbfbf7aSPaul E. McKenney	  For each such CPU, a kthread ("rcuoN") will be created to
6703fbfbf7aSPaul E. McKenney	  invoke callbacks, where the "N" is the CPU being offloaded.
6713fbfbf7aSPaul E. McKenney	  Nothing prevents this kthread from running on the specified
6723fbfbf7aSPaul E. McKenney	  CPUs, but (1) the kthreads may be preempted between each
6733fbfbf7aSPaul E. McKenney	  callback, and (2) affinity or cgroups can be used to force
6743fbfbf7aSPaul E. McKenney	  the kthreads to run on whatever set of CPUs is desired.
6753fbfbf7aSPaul E. McKenney
6763fbfbf7aSPaul E. McKenney	  Say Y here if you want reduced OS jitter on selected CPUs.
6773fbfbf7aSPaul E. McKenney	  Say N here if you are unsure.
6783fbfbf7aSPaul E. McKenney
679c903ff83SMike Travisendmenu # "RCU Subsystem"
680c903ff83SMike Travis
6811da177e4SLinus Torvaldsconfig IKCONFIG
682f2443ab6SRoss Biro	tristate "Kernel .config support"
6831da177e4SLinus Torvalds	---help---
6841da177e4SLinus Torvalds	  This option enables the complete Linux kernel ".config" file
6851da177e4SLinus Torvalds	  contents to be saved in the kernel. It provides documentation
6861da177e4SLinus Torvalds	  of which kernel options are used in a running kernel or in an
6871da177e4SLinus Torvalds	  on-disk kernel.  This information can be extracted from the kernel
6881da177e4SLinus Torvalds	  image file with the script scripts/extract-ikconfig and used as
6891da177e4SLinus Torvalds	  input to rebuild the current kernel or to build another kernel.
6901da177e4SLinus Torvalds	  It can also be extracted from a running kernel by reading
6911da177e4SLinus Torvalds	  /proc/config.gz if enabled (below).
6921da177e4SLinus Torvalds
6931da177e4SLinus Torvaldsconfig IKCONFIG_PROC
6941da177e4SLinus Torvalds	bool "Enable access to .config through /proc/config.gz"
6951da177e4SLinus Torvalds	depends on IKCONFIG && PROC_FS
6961da177e4SLinus Torvalds	---help---
6971da177e4SLinus Torvalds	  This option enables access to the kernel configuration file
6981da177e4SLinus Torvalds	  through /proc/config.gz.
6991da177e4SLinus Torvalds
700794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT
701794543a2SAlistair John Strachan	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
702794543a2SAlistair John Strachan	range 12 21
703f17a32e9SAdrian Bunk	default 17
704794543a2SAlistair John Strachan	help
705794543a2SAlistair John Strachan	  Select kernel log buffer size as a power of 2.
706f17a32e9SAdrian Bunk	  Examples:
707f17a32e9SAdrian Bunk	  	     17 => 128 KB
708f17a32e9SAdrian Bunk		     16 => 64 KB
709f17a32e9SAdrian Bunk	             15 => 32 KB
710f17a32e9SAdrian Bunk	             14 => 16 KB
711794543a2SAlistair John Strachan		     13 =>  8 KB
712794543a2SAlistair John Strachan		     12 =>  4 KB
713794543a2SAlistair John Strachan
7145cdc38f9SKAMEZAWA Hiroyuki#
7155cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this:
7165cdc38f9SKAMEZAWA Hiroyuki#
7175cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK
7185cdc38f9SKAMEZAWA Hiroyuki	bool
7195cdc38f9SKAMEZAWA Hiroyuki
720be3a7284SAndrea Arcangeli#
721be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler
722be3a7284SAndrea Arcangeli# balancing logic:
723be3a7284SAndrea Arcangeli#
724be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING
725be3a7284SAndrea Arcangeli	bool
726be3a7284SAndrea Arcangeli
727be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions
728be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH.
729be3a7284SAndrea Arcangeli#
730be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY
731be3a7284SAndrea Arcangeli	bool
732be3a7284SAndrea Arcangeli
733be3a7284SAndrea Arcangeli#
734be3a7284SAndrea Arcangeli# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
735be3a7284SAndrea Arcangeliconfig ARCH_WANTS_PROT_NUMA_PROT_NONE
736be3a7284SAndrea Arcangeli	bool
737be3a7284SAndrea Arcangeli
738be3a7284SAndrea Arcangeliconfig ARCH_USES_NUMA_PROT_NONE
739be3a7284SAndrea Arcangeli	bool
740be3a7284SAndrea Arcangeli	default y
741be3a7284SAndrea Arcangeli	depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
742be3a7284SAndrea Arcangeli	depends on NUMA_BALANCING
743be3a7284SAndrea Arcangeli
7441a687c2eSMel Gormanconfig NUMA_BALANCING_DEFAULT_ENABLED
7451a687c2eSMel Gorman	bool "Automatically enable NUMA aware memory/task placement"
7461a687c2eSMel Gorman	default y
7471a687c2eSMel Gorman	depends on NUMA_BALANCING
7481a687c2eSMel Gorman	help
7491a687c2eSMel Gorman	  If set, autonumic NUMA balancing will be enabled if running on a NUMA
7501a687c2eSMel Gorman	  machine.
7511a687c2eSMel Gorman
752be3a7284SAndrea Arcangeliconfig NUMA_BALANCING
753be3a7284SAndrea Arcangeli	bool "Memory placement aware NUMA scheduler"
754be3a7284SAndrea Arcangeli	depends on ARCH_SUPPORTS_NUMA_BALANCING
755be3a7284SAndrea Arcangeli	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
756be3a7284SAndrea Arcangeli	depends on SMP && NUMA && MIGRATION
757be3a7284SAndrea Arcangeli	help
758be3a7284SAndrea Arcangeli	  This option adds support for automatic NUMA aware memory/task placement.
759be3a7284SAndrea Arcangeli	  The mechanism is quite primitive and is based on migrating memory when
760be3a7284SAndrea Arcangeli	  it is references to the node the task is running on.
761be3a7284SAndrea Arcangeli
762be3a7284SAndrea Arcangeli	  This system will be inactive on UMA systems.
763be3a7284SAndrea Arcangeli
76423964d2dSLi Zefanmenuconfig CGROUPS
76523964d2dSLi Zefan	boolean "Control Group support"
7660dea1168SKirill A. Shutemov	depends on EVENTFD
767ddbcc7e8SPaul Menage	help
76823964d2dSLi Zefan	  This option adds support for grouping sets of processes together, for
7695cdc38f9SKAMEZAWA Hiroyuki	  use with process control subsystems such as Cpusets, CFS, memory
7705cdc38f9SKAMEZAWA Hiroyuki	  controls or device isolation.
7715cdc38f9SKAMEZAWA Hiroyuki	  See
7725cdc38f9SKAMEZAWA Hiroyuki		- Documentation/scheduler/sched-design-CFS.txt	(CFS)
77345ce80fbSLi Zefan		- Documentation/cgroups/ (features for grouping, isolation
77445ce80fbSLi Zefan					  and resource control)
775ddbcc7e8SPaul Menage
776ddbcc7e8SPaul Menage	  Say N if unsure.
777ddbcc7e8SPaul Menage
77823964d2dSLi Zefanif CGROUPS
77923964d2dSLi Zefan
780006cb992SPaul Menageconfig CGROUP_DEBUG
781006cb992SPaul Menage	bool "Example debug cgroup subsystem"
782418d7d87SPaul Menage	default n
783006cb992SPaul Menage	help
784006cb992SPaul Menage	  This option enables a simple cgroup subsystem that
785006cb992SPaul Menage	  exports useful debugging information about the cgroups
78623964d2dSLi Zefan	  framework.
787006cb992SPaul Menage
78823964d2dSLi Zefan	  Say N if unsure.
789006cb992SPaul Menage
790dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER
79123964d2dSLi Zefan	bool "Freezer cgroup subsystem"
792dc52ddc0SMatt Helsley	help
793dc52ddc0SMatt Helsley	  Provides a way to freeze and unfreeze all tasks in a
794dc52ddc0SMatt Helsley	  cgroup.
795dc52ddc0SMatt Helsley
79608ce5f16SSerge E. Hallynconfig CGROUP_DEVICE
79708ce5f16SSerge E. Hallyn	bool "Device controller for cgroups"
79808ce5f16SSerge E. Hallyn	help
79908ce5f16SSerge E. Hallyn	  Provides a cgroup implementing whitelists for devices which
80008ce5f16SSerge E. Hallyn	  a process in the cgroup can mknod or open.
80108ce5f16SSerge E. Hallyn
8021da177e4SLinus Torvaldsconfig CPUSETS
8031da177e4SLinus Torvalds	bool "Cpuset support"
8041da177e4SLinus Torvalds	help
805d9fd8a6dSRandy Dunlap	  This option will let you create and manage CPUSETs which
8061da177e4SLinus Torvalds	  allow dynamically partitioning a system into sets of CPUs and
8071da177e4SLinus Torvalds	  Memory Nodes and assigning tasks to run only within those sets.
8081da177e4SLinus Torvalds	  This is primarily useful on large SMP or NUMA systems.
8091da177e4SLinus Torvalds
8101da177e4SLinus Torvalds	  Say N if unsure.
8111da177e4SLinus Torvalds
81223964d2dSLi Zefanconfig PROC_PID_CPUSET
81323964d2dSLi Zefan	bool "Include legacy /proc/<pid>/cpuset file"
81423964d2dSLi Zefan	depends on CPUSETS
81523964d2dSLi Zefan	default y
81623964d2dSLi Zefan
817d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT
818d842de87SSrivatsa Vaddagiri	bool "Simple CPU accounting cgroup subsystem"
819d842de87SSrivatsa Vaddagiri	help
820d842de87SSrivatsa Vaddagiri	  Provides a simple Resource Controller for monitoring the
82123964d2dSLi Zefan	  total CPU consumed by the tasks in a cgroup.
822d842de87SSrivatsa Vaddagiri
823e552b661SPavel Emelianovconfig RESOURCE_COUNTERS
824e552b661SPavel Emelianov	bool "Resource counters"
825e552b661SPavel Emelianov	help
826e552b661SPavel Emelianov	  This option enables controller independent resource accounting
82723964d2dSLi Zefan	  infrastructure that works with cgroups.
828e552b661SPavel Emelianov
829c255a458SAndrew Mortonconfig MEMCG
83000f0b825SBalbir Singh	bool "Memory Resource Controller for Control Groups"
83179ae9c29SDaniel Lezcano	depends on RESOURCE_COUNTERS
832cf475ad2SBalbir Singh	select MM_OWNER
83300f0b825SBalbir Singh	help
83484ad6d70SKAMEZAWA Hiroyuki	  Provides a memory resource controller that manages both anonymous
83521acb9caSThadeu Lima de Souza Cascardo	  memory and page cache. (See Documentation/cgroups/memory.txt)
83600f0b825SBalbir Singh
83700f0b825SBalbir Singh	  Note that setting this option increases fixed memory overhead
83884ad6d70SKAMEZAWA Hiroyuki	  associated with each page of memory in the system. By this,
83984ad6d70SKAMEZAWA Hiroyuki	  20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
84084ad6d70SKAMEZAWA Hiroyuki	  usage tracking struct at boot. Total amount of this is printed out
84184ad6d70SKAMEZAWA Hiroyuki	  at boot.
84200f0b825SBalbir Singh
84300f0b825SBalbir Singh	  Only enable when you're ok with these trade offs and really
84484ad6d70SKAMEZAWA Hiroyuki	  sure you need the memory resource controller. Even when you enable
84584ad6d70SKAMEZAWA Hiroyuki	  this, you can set "cgroup_disable=memory" at your boot option to
84684ad6d70SKAMEZAWA Hiroyuki	  disable memory resource controller and you can avoid overheads.
847c9d5409fSLi Zefan	  (and lose benefits of memory resource controller)
84800f0b825SBalbir Singh
849cf475ad2SBalbir Singh	  This config option also selects MM_OWNER config option, which
850cf475ad2SBalbir Singh	  could in turn add some fork/exit overhead.
851cf475ad2SBalbir Singh
852c255a458SAndrew Mortonconfig MEMCG_SWAP
85365e0e811SKAMEZAWA Hiroyuki	bool "Memory Resource Controller Swap Extension"
854c255a458SAndrew Morton	depends on MEMCG && SWAP
855c077719bSKAMEZAWA Hiroyuki	help
856c077719bSKAMEZAWA Hiroyuki	  Add swap management feature to memory resource controller. When you
857c077719bSKAMEZAWA Hiroyuki	  enable this, you can limit mem+swap usage per cgroup. In other words,
858c077719bSKAMEZAWA Hiroyuki	  when you disable this, memory resource controller has no cares to
859c077719bSKAMEZAWA Hiroyuki	  usage of swap...a process can exhaust all of the swap. This extension
860c077719bSKAMEZAWA Hiroyuki	  is useful when you want to avoid exhaustion swap but this itself
861c077719bSKAMEZAWA Hiroyuki	  adds more overheads and consumes memory for remembering information.
862c077719bSKAMEZAWA Hiroyuki	  Especially if you use 32bit system or small memory system, please
863c077719bSKAMEZAWA Hiroyuki	  be careful about enabling this. When memory resource controller
864c077719bSKAMEZAWA Hiroyuki	  is disabled by boot option, this will be automatically disabled and
865c077719bSKAMEZAWA Hiroyuki	  there will be no overhead from this. Even when you set this config=y,
86600a66d29SWANG Cong	  if boot option "swapaccount=0" is set, swap will not be accounted.
867627991a2SKAMEZAWA Hiroyuki	  Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
868627991a2SKAMEZAWA Hiroyuki	  size is 4096bytes, 512k per 1Gbytes of swap.
869c255a458SAndrew Mortonconfig MEMCG_SWAP_ENABLED
870a42c390cSMichal Hocko	bool "Memory Resource Controller Swap Extension enabled by default"
871c255a458SAndrew Morton	depends on MEMCG_SWAP
872a42c390cSMichal Hocko	default y
873a42c390cSMichal Hocko	help
874a42c390cSMichal Hocko	  Memory Resource Controller Swap Extension comes with its price in
875a42c390cSMichal Hocko	  a bigger memory consumption. General purpose distribution kernels
87643d547f9SJim Cromie	  which want to enable the feature but keep it disabled by default
877a42c390cSMichal Hocko	  and let the user enable it by swapaccount boot command line
878a42c390cSMichal Hocko	  parameter should have this option unselected.
879a42c390cSMichal Hocko	  For those who want to have the feature enabled by default should
880a42c390cSMichal Hocko	  select this option (if, for some reason, they need to disable it
88100a66d29SWANG Cong	  then swapaccount=0 does the trick).
882c255a458SAndrew Mortonconfig MEMCG_KMEM
883e5671dfaSGlauber Costa	bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
884c255a458SAndrew Morton	depends on MEMCG && EXPERIMENTAL
885510fc4e1SGlauber Costa	depends on SLUB || SLAB
886e5671dfaSGlauber Costa	help
887e5671dfaSGlauber Costa	  The Kernel Memory extension for Memory Resource Controller can limit
888e5671dfaSGlauber Costa	  the amount of memory used by kernel objects in the system. Those are
889e5671dfaSGlauber Costa	  fundamentally different from the entities handled by the standard
890e5671dfaSGlauber Costa	  Memory Controller, which are page-based, and can be swapped. Users of
891e5671dfaSGlauber Costa	  the kmem extension can use it to guarantee that no group of processes
892e5671dfaSGlauber Costa	  will ever exhaust kernel resources alone.
893c077719bSKAMEZAWA Hiroyuki
8942bc64a20SAneesh Kumar K.Vconfig CGROUP_HUGETLB
8952bc64a20SAneesh Kumar K.V	bool "HugeTLB Resource Controller for Control Groups"
8962bc64a20SAneesh Kumar K.V	depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
8972bc64a20SAneesh Kumar K.V	default n
8982bc64a20SAneesh Kumar K.V	help
8992bc64a20SAneesh Kumar K.V	  Provides a cgroup Resource Controller for HugeTLB pages.
9002bc64a20SAneesh Kumar K.V	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
9012bc64a20SAneesh Kumar K.V	  The limit is enforced during page fault. Since HugeTLB doesn't
9022bc64a20SAneesh Kumar K.V	  support page reclaim, enforcing the limit at page fault time implies
9032bc64a20SAneesh Kumar K.V	  that, the application will get SIGBUS signal if it tries to access
9042bc64a20SAneesh Kumar K.V	  HugeTLB pages beyond its limit. This requires the application to know
9052bc64a20SAneesh Kumar K.V	  beforehand how much HugeTLB pages it would require for its use. The
9062bc64a20SAneesh Kumar K.V	  control group is tracked in the third page lru pointer. This means
9072bc64a20SAneesh Kumar K.V	  that we cannot use the controller with huge page less than 3 pages.
9082bc64a20SAneesh Kumar K.V
909e5d1367fSStephane Eranianconfig CGROUP_PERF
910e5d1367fSStephane Eranian	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
911e5d1367fSStephane Eranian	depends on PERF_EVENTS && CGROUPS
912e5d1367fSStephane Eranian	help
913e5d1367fSStephane Eranian	  This option extends the per-cpu mode to restrict monitoring to
9142d0f2520SLi Zefan	  threads which belong to the cgroup specified and run on the
915e5d1367fSStephane Eranian	  designated cpu.
916e5d1367fSStephane Eranian
917e5d1367fSStephane Eranian	  Say N if unsure.
918e5d1367fSStephane Eranian
9197c941438SDhaval Gianimenuconfig CGROUP_SCHED
9207c941438SDhaval Giani	bool "Group CPU scheduler"
9217c941438SDhaval Giani	default n
9227c941438SDhaval Giani	help
9237c941438SDhaval Giani	  This feature lets CPU scheduler recognize task groups and control CPU
9247c941438SDhaval Giani	  bandwidth allocation to such task groups. It uses cgroups to group
9257c941438SDhaval Giani	  tasks.
9267c941438SDhaval Giani
9277c941438SDhaval Gianiif CGROUP_SCHED
9287c941438SDhaval Gianiconfig FAIR_GROUP_SCHED
9297c941438SDhaval Giani	bool "Group scheduling for SCHED_OTHER"
9307c941438SDhaval Giani	depends on CGROUP_SCHED
9317c941438SDhaval Giani	default CGROUP_SCHED
9327c941438SDhaval Giani
933ab84d31eSPaul Turnerconfig CFS_BANDWIDTH
934ab84d31eSPaul Turner	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
935ab84d31eSPaul Turner	depends on EXPERIMENTAL
936ab84d31eSPaul Turner	depends on FAIR_GROUP_SCHED
937ab84d31eSPaul Turner	default n
938ab84d31eSPaul Turner	help
939ab84d31eSPaul Turner	  This option allows users to define CPU bandwidth rates (limits) for
940ab84d31eSPaul Turner	  tasks running within the fair group scheduler.  Groups with no limit
941ab84d31eSPaul Turner	  set are considered to be unconstrained and will run with no
942ab84d31eSPaul Turner	  restriction.
943ab84d31eSPaul Turner	  See tip/Documentation/scheduler/sched-bwc.txt for more information.
944ab84d31eSPaul Turner
9457c941438SDhaval Gianiconfig RT_GROUP_SCHED
9467c941438SDhaval Giani	bool "Group scheduling for SCHED_RR/FIFO"
9477c941438SDhaval Giani	depends on EXPERIMENTAL
9487c941438SDhaval Giani	depends on CGROUP_SCHED
9497c941438SDhaval Giani	default n
9507c941438SDhaval Giani	help
9517c941438SDhaval Giani	  This feature lets you explicitly allocate real CPU bandwidth
95232bd7eb5SLi Zefan	  to task groups. If enabled, it will also make it impossible to
9537c941438SDhaval Giani	  schedule realtime tasks for non-root users until you allocate
9547c941438SDhaval Giani	  realtime bandwidth for them.
9557c941438SDhaval Giani	  See Documentation/scheduler/sched-rt-group.txt for more information.
9567c941438SDhaval Giani
9577c941438SDhaval Gianiendif #CGROUP_SCHED
9587c941438SDhaval Giani
959afc24d49SVivek Goyalconfig BLK_CGROUP
96032e380aeSTejun Heo	bool "Block IO controller"
96179ae9c29SDaniel Lezcano	depends on BLOCK
962afc24d49SVivek Goyal	default n
963afc24d49SVivek Goyal	---help---
964afc24d49SVivek Goyal	Generic block IO controller cgroup interface. This is the common
965afc24d49SVivek Goyal	cgroup interface which should be used by various IO controlling
966afc24d49SVivek Goyal	policies.
967afc24d49SVivek Goyal
968afc24d49SVivek Goyal	Currently, CFQ IO scheduler uses it to recognize task groups and
969afc24d49SVivek Goyal	control disk bandwidth allocation (proportional time slice allocation)
970e43473b7SVivek Goyal	to such task groups. It is also used by bio throttling logic in
971e43473b7SVivek Goyal	block layer to implement upper limit in IO rates on a device.
972afc24d49SVivek Goyal
973afc24d49SVivek Goyal	This option only enables generic Block IO controller infrastructure.
974e43473b7SVivek Goyal	One needs to also enable actual IO controlling logic/policy. For
97579e2e759SMichael Witten	enabling proportional weight division of disk bandwidth in CFQ, set
97679e2e759SMichael Witten	CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
977c5e0591aSMichael Witten	CONFIG_BLK_DEV_THROTTLING=y.
978afc24d49SVivek Goyal
979afc24d49SVivek Goyal	See Documentation/cgroups/blkio-controller.txt for more information.
980afc24d49SVivek Goyal
981afc24d49SVivek Goyalconfig DEBUG_BLK_CGROUP
982afc24d49SVivek Goyal	bool "Enable Block IO controller debugging"
983afc24d49SVivek Goyal	depends on BLK_CGROUP
984afc24d49SVivek Goyal	default n
985afc24d49SVivek Goyal	---help---
986afc24d49SVivek Goyal	Enable some debugging help. Currently it exports additional stat
987afc24d49SVivek Goyal	files in a cgroup which can be useful for debugging.
988afc24d49SVivek Goyal
98923964d2dSLi Zefanendif # CGROUPS
990c077719bSKAMEZAWA Hiroyuki
991067bce1aSCyrill Gorcunovconfig CHECKPOINT_RESTORE
992067bce1aSCyrill Gorcunov	bool "Checkpoint/restore support" if EXPERT
993067bce1aSCyrill Gorcunov	default n
994067bce1aSCyrill Gorcunov	help
995067bce1aSCyrill Gorcunov	  Enables additional kernel features in a sake of checkpoint/restore.
996067bce1aSCyrill Gorcunov	  In particular it adds auxiliary prctl codes to setup process text,
997067bce1aSCyrill Gorcunov	  data and heap segment sizes, and a few additional /proc filesystem
998067bce1aSCyrill Gorcunov	  entries.
999067bce1aSCyrill Gorcunov
1000067bce1aSCyrill Gorcunov	  If unsure, say N here.
1001067bce1aSCyrill Gorcunov
10028dd2a82cSDaniel Lezcanomenuconfig NAMESPACES
10036a108a14SDavid Rientjes	bool "Namespaces support" if EXPERT
10046a108a14SDavid Rientjes	default !EXPERT
1005c5289a69SPavel Emelyanov	help
1006c5289a69SPavel Emelyanov	  Provides the way to make tasks work with different objects using
1007c5289a69SPavel Emelyanov	  the same id. For example same IPC id may refer to different objects
1008c5289a69SPavel Emelyanov	  or same user id or pid may refer to different tasks when used in
1009c5289a69SPavel Emelyanov	  different namespaces.
1010c5289a69SPavel Emelyanov
10118dd2a82cSDaniel Lezcanoif NAMESPACES
10128dd2a82cSDaniel Lezcano
101358bfdd6dSPavel Emelyanovconfig UTS_NS
101458bfdd6dSPavel Emelyanov	bool "UTS namespace"
101517a6d441SDaniel Lezcano	default y
101658bfdd6dSPavel Emelyanov	help
101758bfdd6dSPavel Emelyanov	  In this namespace tasks see different info provided with the
101858bfdd6dSPavel Emelyanov	  uname() system call
101958bfdd6dSPavel Emelyanov
1020ae5e1b22SPavel Emelyanovconfig IPC_NS
1021ae5e1b22SPavel Emelyanov	bool "IPC namespace"
10228dd2a82cSDaniel Lezcano	depends on (SYSVIPC || POSIX_MQUEUE)
102317a6d441SDaniel Lezcano	default y
1024ae5e1b22SPavel Emelyanov	help
1025ae5e1b22SPavel Emelyanov	  In this namespace tasks work with IPC ids which correspond to
1026614b84cfSSerge E. Hallyn	  different IPC objects in different namespaces.
1027ae5e1b22SPavel Emelyanov
1028aee16ce7SPavel Emelyanovconfig USER_NS
1029aee16ce7SPavel Emelyanov	bool "User namespace (EXPERIMENTAL)"
10308dd2a82cSDaniel Lezcano	depends on EXPERIMENTAL
1031e1c972b6SEric W. Biederman	depends on UIDGID_CONVERTED
10325673a94cSEric W. Biederman	select UIDGID_STRICT_TYPE_CHECKS
1033e1c972b6SEric W. Biederman
10345673a94cSEric W. Biederman	default n
1035aee16ce7SPavel Emelyanov	help
1036aee16ce7SPavel Emelyanov	  This allows containers, i.e. vservers, to use user namespaces
1037aee16ce7SPavel Emelyanov	  to provide different user info for different servers.
1038*e11f0ae3SEric W. Biederman
1039*e11f0ae3SEric W. Biederman	  When user namespaces are enabled in the kernel it is
1040*e11f0ae3SEric W. Biederman	  recommended that the MEMCG and MEMCG_KMEM options also be
1041*e11f0ae3SEric W. Biederman	  enabled and that user-space use the memory control groups to
1042*e11f0ae3SEric W. Biederman	  limit the amount of memory a memory unprivileged users can
1043*e11f0ae3SEric W. Biederman	  use.
1044*e11f0ae3SEric W. Biederman
1045aee16ce7SPavel Emelyanov	  If unsure, say N.
1046aee16ce7SPavel Emelyanov
104774bd59bbSPavel Emelyanovconfig PID_NS
10489bd38c2cSDaniel Lezcano	bool "PID Namespaces"
104917a6d441SDaniel Lezcano	default y
105074bd59bbSPavel Emelyanov	help
105112d2b8f9SHeikki Orsila	  Support process id namespaces.  This allows having multiple
1052692105b8SMatt LaPlante	  processes with the same pid as long as they are in different
105374bd59bbSPavel Emelyanov	  pid namespaces.  This is a building block of containers.
105474bd59bbSPavel Emelyanov
1055d6eb633fSMatt Helsleyconfig NET_NS
1056d6eb633fSMatt Helsley	bool "Network namespace"
10578dd2a82cSDaniel Lezcano	depends on NET
105817a6d441SDaniel Lezcano	default y
1059d6eb633fSMatt Helsley	help
1060d6eb633fSMatt Helsley	  Allow user space to create what appear to be multiple instances
1061d6eb633fSMatt Helsley	  of the network stack.
1062d6eb633fSMatt Helsley
10638dd2a82cSDaniel Lezcanoendif # NAMESPACES
10648dd2a82cSDaniel Lezcano
1065e1c972b6SEric W. Biedermanconfig UIDGID_CONVERTED
1066e1c972b6SEric W. Biederman	# True if all of the selected software conmponents are known
1067e1c972b6SEric W. Biederman	# to have uid_t and gid_t converted to kuid_t and kgid_t
1068e1c972b6SEric W. Biederman	# where appropriate and are otherwise safe to use with
1069e1c972b6SEric W. Biederman	# the user namespace.
1070e1c972b6SEric W. Biederman	bool
1071e1c972b6SEric W. Biederman	default y
1072e1c972b6SEric W. Biederman
1073e1c972b6SEric W. Biederman	# Networking
1074e1c972b6SEric W. Biederman	depends on NET_9P = n
1075e1c972b6SEric W. Biederman
1076e1c972b6SEric W. Biederman	# Filesystems
1077e1c972b6SEric W. Biederman	depends on 9P_FS = n
1078e1c972b6SEric W. Biederman	depends on AFS_FS = n
1079e1c972b6SEric W. Biederman	depends on CEPH_FS = n
1080e1c972b6SEric W. Biederman	depends on CIFS = n
1081e1c972b6SEric W. Biederman	depends on CODA_FS = n
1082e1c972b6SEric W. Biederman	depends on GFS2_FS = n
1083e1c972b6SEric W. Biederman	depends on NCP_FS = n
1084e1c972b6SEric W. Biederman	depends on NFSD = n
1085e1c972b6SEric W. Biederman	depends on NFS_FS = n
1086e1c972b6SEric W. Biederman	depends on OCFS2_FS = n
1087e1c972b6SEric W. Biederman	depends on XFS_FS = n
1088e1c972b6SEric W. Biederman
10895673a94cSEric W. Biedermanconfig UIDGID_STRICT_TYPE_CHECKS
10905673a94cSEric W. Biederman	bool "Require conversions between uid/gids and their internal representation"
1091e1c972b6SEric W. Biederman	depends on UIDGID_CONVERTED
10925673a94cSEric W. Biederman	default n
10935673a94cSEric W. Biederman	help
10945673a94cSEric W. Biederman	 While the nececessary conversions are being added to all subsystems this option allows
10955673a94cSEric W. Biederman	 the code to continue to build for unconverted subsystems.
10965673a94cSEric W. Biederman
10975673a94cSEric W. Biederman	 Say Y here if you want the strict type checking enabled
10985673a94cSEric W. Biederman
10995091faa4SMike Galbraithconfig SCHED_AUTOGROUP
11005091faa4SMike Galbraith	bool "Automatic process group scheduling"
11015091faa4SMike Galbraith	select EVENTFD
11025091faa4SMike Galbraith	select CGROUPS
11035091faa4SMike Galbraith	select CGROUP_SCHED
11045091faa4SMike Galbraith	select FAIR_GROUP_SCHED
11055091faa4SMike Galbraith	help
11065091faa4SMike Galbraith	  This option optimizes the scheduler for common desktop workloads by
11075091faa4SMike Galbraith	  automatically creating and populating task groups.  This separation
11085091faa4SMike Galbraith	  of workloads isolates aggressive CPU burners (like build jobs) from
11095091faa4SMike Galbraith	  desktop applications.  Task group autogeneration is currently based
11105091faa4SMike Galbraith	  upon task session.
11115091faa4SMike Galbraith
11127af37becSDaniel Lezcanoconfig MM_OWNER
11137af37becSDaniel Lezcano	bool
11147af37becSDaniel Lezcano
11157af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED
11165d6a4ea5SFerenc Wagner	bool "Enable deprecated sysfs features to support old userspace tools"
11177af37becSDaniel Lezcano	depends on SYSFS
11187af37becSDaniel Lezcano	default n
11197af37becSDaniel Lezcano	help
11207af37becSDaniel Lezcano	  This option adds code that switches the layout of the "block" class
11217af37becSDaniel Lezcano	  devices, to not show up in /sys/class/block/, but only in
11227af37becSDaniel Lezcano	  /sys/block/.
11237af37becSDaniel Lezcano
11247af37becSDaniel Lezcano	  This switch is only active when the sysfs.deprecated=1 boot option is
11257af37becSDaniel Lezcano	  passed or the SYSFS_DEPRECATED_V2 option is set.
11267af37becSDaniel Lezcano
11277af37becSDaniel Lezcano	  This option allows new kernels to run on old distributions and tools,
11287af37becSDaniel Lezcano	  which might get confused by /sys/class/block/. Since 2007/2008 all
11297af37becSDaniel Lezcano	  major distributions and tools handle this just fine.
11307af37becSDaniel Lezcano
11317af37becSDaniel Lezcano	  Recent distributions and userspace tools after 2009/2010 depend on
11327af37becSDaniel Lezcano	  the existence of /sys/class/block/, and will not work with this
11337af37becSDaniel Lezcano	  option enabled.
11347af37becSDaniel Lezcano
11357af37becSDaniel Lezcano	  Only if you are using a new kernel on an old distribution, you might
11367af37becSDaniel Lezcano	  need to say Y here.
11377af37becSDaniel Lezcano
11387af37becSDaniel Lezcanoconfig SYSFS_DEPRECATED_V2
11395d6a4ea5SFerenc Wagner	bool "Enable deprecated sysfs features by default"
11407af37becSDaniel Lezcano	default n
11417af37becSDaniel Lezcano	depends on SYSFS
11427af37becSDaniel Lezcano	depends on SYSFS_DEPRECATED
11437af37becSDaniel Lezcano	help
11447af37becSDaniel Lezcano	  Enable deprecated sysfs by default.
11457af37becSDaniel Lezcano
11467af37becSDaniel Lezcano	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
11477af37becSDaniel Lezcano	  option.
11487af37becSDaniel Lezcano
11497af37becSDaniel Lezcano	  Only if you are using a new kernel on an old distribution, you might
11507af37becSDaniel Lezcano	  need to say Y here. Even then, odds are you would not need it
11517af37becSDaniel Lezcano	  enabled, you can always pass the boot option if absolutely necessary.
11527af37becSDaniel Lezcano
11537af37becSDaniel Lezcanoconfig RELAY
11547af37becSDaniel Lezcano	bool "Kernel->user space relay support (formerly relayfs)"
11557af37becSDaniel Lezcano	help
11567af37becSDaniel Lezcano	  This option enables support for relay interface support in
11577af37becSDaniel Lezcano	  certain file systems (such as debugfs).
11587af37becSDaniel Lezcano	  It is designed to provide an efficient mechanism for tools and
11597af37becSDaniel Lezcano	  facilities to relay large amounts of data from kernel space to
11607af37becSDaniel Lezcano	  user space.
11617af37becSDaniel Lezcano
11627af37becSDaniel Lezcano	  If unsure, say N.
11637af37becSDaniel Lezcano
1164f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD
1165f991633dSDimitri Gorokhovik	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1166f991633dSDimitri Gorokhovik	depends on BROKEN || !FRV
1167f991633dSDimitri Gorokhovik	help
1168f991633dSDimitri Gorokhovik	  The initial RAM filesystem is a ramfs which is loaded by the
1169f991633dSDimitri Gorokhovik	  boot loader (loadlin or lilo) and that is mounted as root
1170f991633dSDimitri Gorokhovik	  before the normal boot procedure. It is typically used to
1171f991633dSDimitri Gorokhovik	  load modules needed to mount the "real" root file system,
1172f991633dSDimitri Gorokhovik	  etc. See <file:Documentation/initrd.txt> for details.
1173f991633dSDimitri Gorokhovik
1174f991633dSDimitri Gorokhovik	  If RAM disk support (BLK_DEV_RAM) is also included, this
1175f991633dSDimitri Gorokhovik	  also enables initial RAM disk (initrd) support and adds
1176f991633dSDimitri Gorokhovik	  15 Kbytes (more on some other architectures) to the kernel size.
1177f991633dSDimitri Gorokhovik
1178f991633dSDimitri Gorokhovik	  If unsure say Y.
1179f991633dSDimitri Gorokhovik
1180c33df4eaSJean-Paul Samanif BLK_DEV_INITRD
1181c33df4eaSJean-Paul Saman
1182dbec4866SSam Ravnborgsource "usr/Kconfig"
1183dbec4866SSam Ravnborg
1184c33df4eaSJean-Paul Samanendif
1185c33df4eaSJean-Paul Saman
1186c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE
118796fffeb4SIngo Molnar	bool "Optimize for size"
1188c45b4f1fSLinus Torvalds	help
1189c45b4f1fSLinus Torvalds	  Enabling this option will pass "-Os" instead of "-O2" to gcc
1190c45b4f1fSLinus Torvalds	  resulting in a smaller kernel.
1191c45b4f1fSLinus Torvalds
1192775a7229Sjkacur	  If unsure, say Y.
1193c45b4f1fSLinus Torvalds
11940847062aSRandy Dunlapconfig SYSCTL
11950847062aSRandy Dunlap	bool
11960847062aSRandy Dunlap
1197b943c460SRandy Dunlapconfig ANON_INODES
1198b943c460SRandy Dunlap	bool
1199b943c460SRandy Dunlap
12006a108a14SDavid Rientjesmenuconfig EXPERT
12016a108a14SDavid Rientjes	bool "Configure standard kernel features (expert users)"
1202f505c553SJosh Triplett	# Unhide debug options, to make the on-by-default options visible
1203f505c553SJosh Triplett	select DEBUG_KERNEL
12041da177e4SLinus Torvalds	help
12051da177e4SLinus Torvalds	  This option allows certain base kernel options and settings
12061da177e4SLinus Torvalds          to be disabled or tweaked. This is for specialized
12071da177e4SLinus Torvalds          environments which can tolerate a "non-standard" kernel.
12081da177e4SLinus Torvalds          Only use this if you really know what you are doing.
12091da177e4SLinus Torvalds
1210af1839ebSCatalin Marinasconfig HAVE_UID16
1211af1839ebSCatalin Marinas	bool
1212af1839ebSCatalin Marinas
1213ae81f9e3SChuck Ebbertconfig UID16
12146a108a14SDavid Rientjes	bool "Enable 16-bit UID system calls" if EXPERT
1215af1839ebSCatalin Marinas	depends on HAVE_UID16
1216ae81f9e3SChuck Ebbert	default y
1217ae81f9e3SChuck Ebbert	help
1218ae81f9e3SChuck Ebbert	  This enables the legacy 16-bit UID syscall wrappers.
1219ae81f9e3SChuck Ebbert
1220b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL
12216a108a14SDavid Rientjes	bool "Sysctl syscall support" if EXPERT
122226a7034bSEric W. Biederman	depends on PROC_SYSCTL
1223c736de60SWANG Cong	default n
1224b89a8171SEric W. Biederman	select SYSCTL
1225b89a8171SEric W. Biederman	---help---
122613bb7e37SEric W. Biederman	  sys_sysctl uses binary paths that have been found challenging
122713bb7e37SEric W. Biederman	  to properly maintain and use.  The interface in /proc/sys
122813bb7e37SEric W. Biederman	  using paths with ascii names is now the primary path to this
122913bb7e37SEric W. Biederman	  information.
1230b89a8171SEric W. Biederman
123113bb7e37SEric W. Biederman	  Almost nothing using the binary sysctl interface so if you are
123213bb7e37SEric W. Biederman	  trying to save some space it is probably safe to disable this,
123313bb7e37SEric W. Biederman	  making your kernel marginally smaller.
1234b89a8171SEric W. Biederman
1235c736de60SWANG Cong	  If unsure say N here.
1236ae81f9e3SChuck Ebbert
12377ac57a89SCatalin Marinasconfig SYSCTL_EXCEPTION_TRACE
12387ac57a89SCatalin Marinas	bool
12397ac57a89SCatalin Marinas	help
12407ac57a89SCatalin Marinas	  Enable support for /proc/sys/debug/exception-trace.
12417ac57a89SCatalin Marinas
12421da177e4SLinus Torvaldsconfig KALLSYMS
12436a108a14SDavid Rientjes	 bool "Load all symbols for debugging/ksymoops" if EXPERT
12441da177e4SLinus Torvalds	 default y
12451da177e4SLinus Torvalds	 help
12461da177e4SLinus Torvalds	   Say Y here to let the kernel print out symbolic crash information and
12471da177e4SLinus Torvalds	   symbolic stack backtraces. This increases the size of the kernel
12481da177e4SLinus Torvalds	   somewhat, as all symbols have to be loaded into the kernel image.
12491da177e4SLinus Torvalds
12501da177e4SLinus Torvaldsconfig KALLSYMS_ALL
12511da177e4SLinus Torvalds	bool "Include all symbols in kallsyms"
12521da177e4SLinus Torvalds	depends on DEBUG_KERNEL && KALLSYMS
12531da177e4SLinus Torvalds	help
125471a83ec7SArtem Bityutskiy	   Normally kallsyms only contains the symbols of functions for nicer
125571a83ec7SArtem Bityutskiy	   OOPS messages and backtraces (i.e., symbols from the text and inittext
125671a83ec7SArtem Bityutskiy	   sections). This is sufficient for most cases. And only in very rare
125771a83ec7SArtem Bityutskiy	   cases (e.g., when a debugger is used) all symbols are required (e.g.,
125871a83ec7SArtem Bityutskiy	   names of variables from the data sections, etc).
12591da177e4SLinus Torvalds
126071a83ec7SArtem Bityutskiy	   This option makes sure that all symbols are loaded into the kernel
126171a83ec7SArtem Bityutskiy	   image (i.e., symbols from all sections) in cost of increased kernel
126271a83ec7SArtem Bityutskiy	   size (depending on the kernel configuration, it may be 300KiB or
126371a83ec7SArtem Bityutskiy	   something like this).
12641da177e4SLinus Torvalds
126571a83ec7SArtem Bityutskiy	   Say N unless you really need all symbols.
1266d59745ceSMatt Mackall
1267712f47ceSGreg Kroah-Hartmanconfig HOTPLUG
126845f035abSGreg Kroah-Hartman	def_bool y
1269712f47ceSGreg Kroah-Hartman
1270d59745ceSMatt Mackallconfig PRINTK
1271d59745ceSMatt Mackall	default y
12726a108a14SDavid Rientjes	bool "Enable support for printk" if EXPERT
1273d59745ceSMatt Mackall	help
1274d59745ceSMatt Mackall	  This option enables normal printk support. Removing it
1275d59745ceSMatt Mackall	  eliminates most of the message strings from the kernel image
1276d59745ceSMatt Mackall	  and makes the kernel more or less silent. As this makes it
1277d59745ceSMatt Mackall	  very difficult to diagnose system problems, saying N here is
1278d59745ceSMatt Mackall	  strongly discouraged.
1279d59745ceSMatt Mackall
1280c8538a7aSMatt Mackallconfig BUG
12816a108a14SDavid Rientjes	bool "BUG() support" if EXPERT
1282c8538a7aSMatt Mackall	default y
1283c8538a7aSMatt Mackall	help
1284c8538a7aSMatt Mackall          Disabling this option eliminates support for BUG and WARN, reducing
1285c8538a7aSMatt Mackall          the size of your kernel image and potentially quietly ignoring
1286c8538a7aSMatt Mackall          numerous fatal conditions. You should only consider disabling this
1287c8538a7aSMatt Mackall          option for embedded systems with no facilities for reporting errors.
1288c8538a7aSMatt Mackall          Just say Y.
1289c8538a7aSMatt Mackall
1290708e9a79SMatt Mackallconfig ELF_CORE
1291046d662fSAlex Kelly	depends on COREDUMP
1292708e9a79SMatt Mackall	default y
12936a108a14SDavid Rientjes	bool "Enable ELF core dumps" if EXPERT
1294708e9a79SMatt Mackall	help
1295708e9a79SMatt Mackall	  Enable support for generating core dumps. Disabling saves about 4k.
1296708e9a79SMatt Mackall
12978761f1abSRalf Baechle
1298e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM
12996a108a14SDavid Rientjes	bool "Enable PC-Speaker support" if EXPERT
13008761f1abSRalf Baechle	depends on HAVE_PCSPKR_PLATFORM
130115f304b6SRalf Baechle	select I8253_LOCK
1302e5e1d3cbSStas Sergeev	default y
1303e5e1d3cbSStas Sergeev	help
1304e5e1d3cbSStas Sergeev          This option allows to disable the internal PC-Speaker
1305e5e1d3cbSStas Sergeev          support, saving some memory.
1306e5e1d3cbSStas Sergeev
13078761f1abSRalf Baechleconfig HAVE_PCSPKR_PLATFORM
13088761f1abSRalf Baechle	bool
13098761f1abSRalf Baechle
13101da177e4SLinus Torvaldsconfig BASE_FULL
13111da177e4SLinus Torvalds	default y
13126a108a14SDavid Rientjes	bool "Enable full-sized data structures for core" if EXPERT
13131da177e4SLinus Torvalds	help
13141da177e4SLinus Torvalds	  Disabling this option reduces the size of miscellaneous core
13151da177e4SLinus Torvalds	  kernel data structures. This saves memory on small machines,
13161da177e4SLinus Torvalds	  but may reduce performance.
13171da177e4SLinus Torvalds
13181da177e4SLinus Torvaldsconfig FUTEX
13196a108a14SDavid Rientjes	bool "Enable futex support" if EXPERT
13201da177e4SLinus Torvalds	default y
132123f78d4aSIngo Molnar	select RT_MUTEXES
13221da177e4SLinus Torvalds	help
13231da177e4SLinus Torvalds	  Disabling this option will cause the kernel to be built without
13241da177e4SLinus Torvalds	  support for "fast userspace mutexes".  The resulting kernel may not
13251da177e4SLinus Torvalds	  run glibc-based applications correctly.
13261da177e4SLinus Torvalds
13271da177e4SLinus Torvaldsconfig EPOLL
13286a108a14SDavid Rientjes	bool "Enable eventpoll support" if EXPERT
13291da177e4SLinus Torvalds	default y
1330448e3ceeSAdrian Bunk	select ANON_INODES
13311da177e4SLinus Torvalds	help
13321da177e4SLinus Torvalds	  Disabling this option will cause the kernel to be built without
13331da177e4SLinus Torvalds	  support for epoll family of system calls.
13341da177e4SLinus Torvalds
1335fba2afaaSDavide Libenziconfig SIGNALFD
13366a108a14SDavid Rientjes	bool "Enable signalfd() system call" if EXPERT
1337448e3ceeSAdrian Bunk	select ANON_INODES
1338fba2afaaSDavide Libenzi	default y
1339fba2afaaSDavide Libenzi	help
1340fba2afaaSDavide Libenzi	  Enable the signalfd() system call that allows to receive signals
1341fba2afaaSDavide Libenzi	  on a file descriptor.
1342fba2afaaSDavide Libenzi
1343fba2afaaSDavide Libenzi	  If unsure, say Y.
1344fba2afaaSDavide Libenzi
1345b215e283SDavide Libenziconfig TIMERFD
13466a108a14SDavid Rientjes	bool "Enable timerfd() system call" if EXPERT
1347448e3ceeSAdrian Bunk	select ANON_INODES
1348b215e283SDavide Libenzi	default y
1349b215e283SDavide Libenzi	help
1350b215e283SDavide Libenzi	  Enable the timerfd() system call that allows to receive timer
1351b215e283SDavide Libenzi	  events on a file descriptor.
1352b215e283SDavide Libenzi
1353b215e283SDavide Libenzi	  If unsure, say Y.
1354b215e283SDavide Libenzi
1355e1ad7468SDavide Libenziconfig EVENTFD
13566a108a14SDavid Rientjes	bool "Enable eventfd() system call" if EXPERT
1357448e3ceeSAdrian Bunk	select ANON_INODES
1358e1ad7468SDavide Libenzi	default y
1359e1ad7468SDavide Libenzi	help
1360e1ad7468SDavide Libenzi	  Enable the eventfd() system call that allows to receive both
1361e1ad7468SDavide Libenzi	  kernel notification (ie. KAIO) or userspace notifications.
1362e1ad7468SDavide Libenzi
1363e1ad7468SDavide Libenzi	  If unsure, say Y.
1364e1ad7468SDavide Libenzi
13651da177e4SLinus Torvaldsconfig SHMEM
13666a108a14SDavid Rientjes	bool "Use full shmem filesystem" if EXPERT
13671da177e4SLinus Torvalds	default y
13681da177e4SLinus Torvalds	depends on MMU
13691da177e4SLinus Torvalds	help
13701da177e4SLinus Torvalds	  The shmem is an internal filesystem used to manage shared memory.
13711da177e4SLinus Torvalds	  It is backed by swap and manages resource limits. It is also exported
13721da177e4SLinus Torvalds	  to userspace as tmpfs if TMPFS is enabled. Disabling this
13731da177e4SLinus Torvalds	  option replaces shmem and tmpfs with the much simpler ramfs code,
13741da177e4SLinus Torvalds	  which may be appropriate on small systems without swap.
13751da177e4SLinus Torvalds
1376ebf3f09cSThomas Petazzoniconfig AIO
13776a108a14SDavid Rientjes	bool "Enable AIO support" if EXPERT
1378ebf3f09cSThomas Petazzoni	default y
1379ebf3f09cSThomas Petazzoni	help
1380ebf3f09cSThomas Petazzoni	  This option enables POSIX asynchronous I/O which may by used
1381ebf3f09cSThomas Petazzoni          by some high performance threaded applications. Disabling
1382ebf3f09cSThomas Petazzoni          this option saves about 7k.
1383ebf3f09cSThomas Petazzoni
13846befe5f6SRandy Dunlapconfig EMBEDDED
13856befe5f6SRandy Dunlap	bool "Embedded system"
13866befe5f6SRandy Dunlap	select EXPERT
13876befe5f6SRandy Dunlap	help
13886befe5f6SRandy Dunlap	  This option should be enabled if compiling the kernel for
13896befe5f6SRandy Dunlap	  an embedded system so certain expert options are available
13906befe5f6SRandy Dunlap	  for configuration.
13916befe5f6SRandy Dunlap
1392cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS
13930793a61dSThomas Gleixner	bool
1394018df72dSMike Frysinger	help
1395018df72dSMike Frysinger	  See tools/perf/design.txt for details.
13960793a61dSThomas Gleixner
1397906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC
1398906010b2SPeter Zijlstra	bool
1399906010b2SPeter Zijlstra	help
1400906010b2SPeter Zijlstra	  See tools/perf/design.txt for details
1401906010b2SPeter Zijlstra
140257c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters"
14030793a61dSThomas Gleixner
1404cdd6c482SIngo Molnarconfig PERF_EVENTS
140557c0c15bSIngo Molnar	bool "Kernel performance events and counters"
1406392d65a9SRobert Richter	default y if PROFILING
1407cdd6c482SIngo Molnar	depends on HAVE_PERF_EVENTS
14084c59e467SIngo Molnar	select ANON_INODES
1409e360adbeSPeter Zijlstra	select IRQ_WORK
14100793a61dSThomas Gleixner	help
141157c0c15bSIngo Molnar	  Enable kernel support for various performance events provided
141257c0c15bSIngo Molnar	  by software and hardware.
14130793a61dSThomas Gleixner
1414dd77038dSThadeu Lima de Souza Cascardo	  Software events are supported either built-in or via the
141557c0c15bSIngo Molnar	  use of generic tracepoints.
141657c0c15bSIngo Molnar
141757c0c15bSIngo Molnar	  Most modern CPUs support performance events via performance
141857c0c15bSIngo Molnar	  counter registers. These registers count the number of certain
14190793a61dSThomas Gleixner	  types of hw events: such as instructions executed, cachemisses
14200793a61dSThomas Gleixner	  suffered, or branches mis-predicted - without slowing down the
14210793a61dSThomas Gleixner	  kernel or applications. These registers can also trigger interrupts
14220793a61dSThomas Gleixner	  when a threshold number of events have passed - and can thus be
14230793a61dSThomas Gleixner	  used to profile the code that runs on that CPU.
14240793a61dSThomas Gleixner
142557c0c15bSIngo Molnar	  The Linux Performance Event subsystem provides an abstraction of
1426dd77038dSThadeu Lima de Souza Cascardo	  these software and hardware event capabilities, available via a
142757c0c15bSIngo Molnar	  system call and used by the "perf" utility in tools/perf/. It
14280793a61dSThomas Gleixner	  provides per task and per CPU counters, and it provides event
14290793a61dSThomas Gleixner	  capabilities on top of those.
14300793a61dSThomas Gleixner
14310793a61dSThomas Gleixner	  Say Y if unsure.
14320793a61dSThomas Gleixner
1433906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC
1434906010b2SPeter Zijlstra	default n
1435906010b2SPeter Zijlstra	bool "Debug: use vmalloc to back perf mmap() buffers"
1436906010b2SPeter Zijlstra	depends on PERF_EVENTS && DEBUG_KERNEL
1437906010b2SPeter Zijlstra	select PERF_USE_VMALLOC
1438906010b2SPeter Zijlstra	help
1439906010b2SPeter Zijlstra	 Use vmalloc memory to back perf mmap() buffers.
1440906010b2SPeter Zijlstra
1441906010b2SPeter Zijlstra	 Mostly useful for debugging the vmalloc code on platforms
1442906010b2SPeter Zijlstra	 that don't require it.
1443906010b2SPeter Zijlstra
1444906010b2SPeter Zijlstra	 Say N if unsure.
1445906010b2SPeter Zijlstra
14460793a61dSThomas Gleixnerendmenu
14470793a61dSThomas Gleixner
1448f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS
1449f8891e5eSChristoph Lameter	default y
14506a108a14SDavid Rientjes	bool "Enable VM event counters for /proc/vmstat" if EXPERT
1451f8891e5eSChristoph Lameter	help
14522aea4fb6SPaul Jackson	  VM event counters are needed for event counts to be shown.
14532aea4fb6SPaul Jackson	  This option allows the disabling of the VM event counters
14546a108a14SDavid Rientjes	  on EXPERT systems.  /proc/vmstat will only show page counts
14552aea4fb6SPaul Jackson	  if VM event counters are disabled.
1456f8891e5eSChristoph Lameter
14573d137310SThomas Petazzoniconfig PCI_QUIRKS
14583d137310SThomas Petazzoni	default y
14596a108a14SDavid Rientjes	bool "Enable PCI quirk workarounds" if EXPERT
146061cfc7e4SGeert Uytterhoeven	depends on PCI
14613d137310SThomas Petazzoni	help
14623d137310SThomas Petazzoni	  This enables workarounds for various PCI chipset
14633d137310SThomas Petazzoni          bugs/quirks. Disable this only if your target machine is
14643d137310SThomas Petazzoni          unaffected by PCI quirks.
14653d137310SThomas Petazzoni
146641ecc55bSChristoph Lameterconfig SLUB_DEBUG
146741ecc55bSChristoph Lameter	default y
14686a108a14SDavid Rientjes	bool "Enable SLUB debugging support" if EXPERT
1469f6acb635SChristoph Lameter	depends on SLUB && SYSFS
147041ecc55bSChristoph Lameter	help
147141ecc55bSChristoph Lameter	  SLUB has extensive debug support features. Disabling these can
147241ecc55bSChristoph Lameter	  result in significant savings in code size. This also disables
147341ecc55bSChristoph Lameter	  SLUB sysfs support. /sys/slab will not exist and there will be
147441ecc55bSChristoph Lameter	  no support for cache validation etc.
147541ecc55bSChristoph Lameter
1476b943c460SRandy Dunlapconfig COMPAT_BRK
1477b943c460SRandy Dunlap	bool "Disable heap randomization"
1478b943c460SRandy Dunlap	default y
1479b943c460SRandy Dunlap	help
1480b943c460SRandy Dunlap	  Randomizing heap placement makes heap exploits harder, but it
1481b943c460SRandy Dunlap	  also breaks ancient binaries (including anything libc5 based).
1482b943c460SRandy Dunlap	  This option changes the bootup default to heap randomization
1483692105b8SMatt LaPlante	  disabled, and can be overridden at runtime by setting
1484b943c460SRandy Dunlap	  /proc/sys/kernel/randomize_va_space to 2.
1485b943c460SRandy Dunlap
1486b943c460SRandy Dunlap	  On non-ancient distros (post-2000 ones) N is usually a safe choice.
1487b943c460SRandy Dunlap
148881819f0fSChristoph Lameterchoice
148981819f0fSChristoph Lameter	prompt "Choose SLAB allocator"
1490a0acd820SChristoph Lameter	default SLUB
149181819f0fSChristoph Lameter	help
149281819f0fSChristoph Lameter	   This option allows to select a slab allocator.
149381819f0fSChristoph Lameter
149481819f0fSChristoph Lameterconfig SLAB
149581819f0fSChristoph Lameter	bool "SLAB"
149681819f0fSChristoph Lameter	help
149781819f0fSChristoph Lameter	  The regular slab allocator that is established and known to work
149834013886SChristoph Lameter	  well in all environments. It organizes cache hot objects in
149902f56210SSimon Arlott	  per cpu and per node queues.
150081819f0fSChristoph Lameter
150181819f0fSChristoph Lameterconfig SLUB
150281819f0fSChristoph Lameter	bool "SLUB (Unqueued Allocator)"
150381819f0fSChristoph Lameter	help
150481819f0fSChristoph Lameter	   SLUB is a slab allocator that minimizes cache line usage
150581819f0fSChristoph Lameter	   instead of managing queues of cached objects (SLAB approach).
150681819f0fSChristoph Lameter	   Per cpu caching is realized using slabs of objects instead
150781819f0fSChristoph Lameter	   of queues of objects. SLUB can use memory efficiently
150802f56210SSimon Arlott	   and has enhanced diagnostics. SLUB is the default choice for
150902f56210SSimon Arlott	   a slab allocator.
151081819f0fSChristoph Lameter
151181819f0fSChristoph Lameterconfig SLOB
15126a108a14SDavid Rientjes	depends on EXPERT
151381819f0fSChristoph Lameter	bool "SLOB (Simple Allocator)"
151481819f0fSChristoph Lameter	help
151537291458SMatt Mackall	   SLOB replaces the stock allocator with a drastically simpler
151637291458SMatt Mackall	   allocator. SLOB is generally more space efficient but
151737291458SMatt Mackall	   does not perform as well on large systems.
151881819f0fSChristoph Lameter
151981819f0fSChristoph Lameterendchoice
152081819f0fSChristoph Lameter
1521ea637639SJie Zhangconfig MMAP_ALLOW_UNINITIALIZED
1522ea637639SJie Zhang	bool "Allow mmapped anonymous memory to be uninitialized"
15236a108a14SDavid Rientjes	depends on EXPERT && !MMU
1524ea637639SJie Zhang	default n
1525ea637639SJie Zhang	help
1526ea637639SJie Zhang	  Normally, and according to the Linux spec, anonymous memory obtained
1527ea637639SJie Zhang	  from mmap() has it's contents cleared before it is passed to
1528ea637639SJie Zhang	  userspace.  Enabling this config option allows you to request that
1529ea637639SJie Zhang	  mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1530ea637639SJie Zhang	  providing a huge performance boost.  If this option is not enabled,
1531ea637639SJie Zhang	  then the flag will be ignored.
1532ea637639SJie Zhang
1533ea637639SJie Zhang	  This is taken advantage of by uClibc's malloc(), and also by
1534ea637639SJie Zhang	  ELF-FDPIC binfmt's brk and stack allocator.
1535ea637639SJie Zhang
1536ea637639SJie Zhang	  Because of the obvious security issues, this option should only be
1537ea637639SJie Zhang	  enabled on embedded devices where you control what is run in
1538ea637639SJie Zhang	  userspace.  Since that isn't generally a problem on no-MMU systems,
1539ea637639SJie Zhang	  it is normally safe to say Y here.
1540ea637639SJie Zhang
1541ea637639SJie Zhang	  See Documentation/nommu-mmap.txt for more information.
1542ea637639SJie Zhang
1543125e5645SMathieu Desnoyersconfig PROFILING
1544b309a294SRobert Richter	bool "Profiling support"
1545125e5645SMathieu Desnoyers	help
1546125e5645SMathieu Desnoyers	  Say Y here to enable the extended profiling support mechanisms used
1547125e5645SMathieu Desnoyers	  by profilers such as OProfile.
1548125e5645SMathieu Desnoyers
15495f87f112SIngo Molnar#
15505f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be
15515f87f112SIngo Molnar# dynamically changed for a probe function.
15525f87f112SIngo Molnar#
155397e1c18eSMathieu Desnoyersconfig TRACEPOINTS
15545f87f112SIngo Molnar	bool
155597e1c18eSMathieu Desnoyers
1556fb32e03fSMathieu Desnoyerssource "arch/Kconfig"
1557fb32e03fSMathieu Desnoyers
15581da177e4SLinus Torvaldsendmenu		# General setup
15591da177e4SLinus Torvalds
1560ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT
1561ee7e5516SDmitry Baryshkov	bool
1562ee7e5516SDmitry Baryshkov	default n
1563ee7e5516SDmitry Baryshkov
1564158a9624SLinus Torvaldsconfig SLABINFO
1565158a9624SLinus Torvalds	bool
1566158a9624SLinus Torvalds	depends on PROC_FS
15670f389ec6SChristoph Lameter	depends on SLAB || SLUB_DEBUG
1568158a9624SLinus Torvalds	default y
1569158a9624SLinus Torvalds
1570ae81f9e3SChuck Ebbertconfig RT_MUTEXES
1571ae81f9e3SChuck Ebbert	boolean
1572ae81f9e3SChuck Ebbert
15731da177e4SLinus Torvaldsconfig BASE_SMALL
15741da177e4SLinus Torvalds	int
15751da177e4SLinus Torvalds	default 0 if BASE_FULL
15761da177e4SLinus Torvalds	default 1 if !BASE_FULL
15771da177e4SLinus Torvalds
157866da5733SJan Engelhardtmenuconfig MODULES
15791da177e4SLinus Torvalds	bool "Enable loadable module support"
15801da177e4SLinus Torvalds	help
15811da177e4SLinus Torvalds	  Kernel modules are small pieces of compiled code which can
15821da177e4SLinus Torvalds	  be inserted in the running kernel, rather than being
15831da177e4SLinus Torvalds	  permanently built into the kernel.  You use the "modprobe"
15841da177e4SLinus Torvalds	  tool to add (and sometimes remove) them.  If you say Y here,
15851da177e4SLinus Torvalds	  many parts of the kernel can be built as modules (by
15861da177e4SLinus Torvalds	  answering M instead of Y where indicated): this is most
15871da177e4SLinus Torvalds	  useful for infrequently used options which are not required
15881da177e4SLinus Torvalds	  for booting.  For more information, see the man pages for
15891da177e4SLinus Torvalds	  modprobe, lsmod, modinfo, insmod and rmmod.
15901da177e4SLinus Torvalds
15911da177e4SLinus Torvalds	  If you say Y here, you will need to run "make
15921da177e4SLinus Torvalds	  modules_install" to put the modules under /lib/modules/
15931da177e4SLinus Torvalds	  where modprobe can find them (you may need to be root to do
15941da177e4SLinus Torvalds	  this).
15951da177e4SLinus Torvalds
15961da177e4SLinus Torvalds	  If unsure, say Y.
15971da177e4SLinus Torvalds
15980b0de144SRobert P. J. Dayif MODULES
15990b0de144SRobert P. J. Day
1600826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD
1601826e4506SLinus Torvalds	bool "Forced module loading"
1602826e4506SLinus Torvalds	default n
1603826e4506SLinus Torvalds	help
160491e37a79SRusty Russell	  Allow loading of modules without version information (ie. modprobe
160591e37a79SRusty Russell	  --force).  Forced module loading sets the 'F' (forced) taint flag and
160691e37a79SRusty Russell	  is usually a really bad idea.
1607826e4506SLinus Torvalds
16081da177e4SLinus Torvaldsconfig MODULE_UNLOAD
16091da177e4SLinus Torvalds	bool "Module unloading"
16101da177e4SLinus Torvalds	help
16111da177e4SLinus Torvalds	  Without this option you will not be able to unload any
16121da177e4SLinus Torvalds	  modules (note that some modules may not be unloadable
1613f7f5b675SDenys Vlasenko	  anyway), which makes your kernel smaller, faster
1614f7f5b675SDenys Vlasenko	  and simpler.  If unsure, say Y.
16151da177e4SLinus Torvalds
16161da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD
16171da177e4SLinus Torvalds	bool "Forced module unloading"
16181da177e4SLinus Torvalds	depends on MODULE_UNLOAD && EXPERIMENTAL
16191da177e4SLinus Torvalds	help
16201da177e4SLinus Torvalds	  This option allows you to force a module to unload, even if the
16211da177e4SLinus Torvalds	  kernel believes it is unsafe: the kernel will remove the module
16221da177e4SLinus Torvalds	  without waiting for anyone to stop using it (using the -f option to
16231da177e4SLinus Torvalds	  rmmod).  This is mainly for kernel developers and desperate users.
16241da177e4SLinus Torvalds	  If unsure, say N.
16251da177e4SLinus Torvalds
16261da177e4SLinus Torvaldsconfig MODVERSIONS
16270d541643SSam Ravnborg	bool "Module versioning support"
16281da177e4SLinus Torvalds	help
16291da177e4SLinus Torvalds	  Usually, you have to use modules compiled with your kernel.
16301da177e4SLinus Torvalds	  Saying Y here makes it sometimes possible to use modules
16311da177e4SLinus Torvalds	  compiled for different kernels, by adding enough information
16321da177e4SLinus Torvalds	  to the modules to (hopefully) spot any changes which would
16331da177e4SLinus Torvalds	  make them incompatible with the kernel you are running.  If
16341da177e4SLinus Torvalds	  unsure, say N.
16351da177e4SLinus Torvalds
16361da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL
16371da177e4SLinus Torvalds	bool "Source checksum for all modules"
16381da177e4SLinus Torvalds	help
16391da177e4SLinus Torvalds	  Modules which contain a MODULE_VERSION get an extra "srcversion"
16401da177e4SLinus Torvalds	  field inserted into their modinfo section, which contains a
16411da177e4SLinus Torvalds    	  sum of the source files which made it.  This helps maintainers
16421da177e4SLinus Torvalds	  see exactly which source was used to build a module (since
16431da177e4SLinus Torvalds	  others sometimes change the module source without updating
16441da177e4SLinus Torvalds	  the version).  With this option, such a "srcversion" field
16451da177e4SLinus Torvalds	  will be created for all modules.  If unsure, say N.
16461da177e4SLinus Torvalds
1647106a4ee2SRusty Russellconfig MODULE_SIG
1648106a4ee2SRusty Russell	bool "Module signature verification"
1649106a4ee2SRusty Russell	depends on MODULES
165048ba2462SDavid Howells	select KEYS
165148ba2462SDavid Howells	select CRYPTO
165248ba2462SDavid Howells	select ASYMMETRIC_KEY_TYPE
165348ba2462SDavid Howells	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
165448ba2462SDavid Howells	select PUBLIC_KEY_ALGO_RSA
165548ba2462SDavid Howells	select ASN1
165648ba2462SDavid Howells	select OID_REGISTRY
165748ba2462SDavid Howells	select X509_CERTIFICATE_PARSER
1658106a4ee2SRusty Russell	help
1659106a4ee2SRusty Russell	  Check modules for valid signatures upon load: the signature
1660106a4ee2SRusty Russell	  is simply appended to the module. For more information see
1661106a4ee2SRusty Russell	  Documentation/module-signing.txt.
1662106a4ee2SRusty Russell
1663ea0b6dcfSDavid Howells	  !!!WARNING!!!  If you enable this option, you MUST make sure that the
1664ea0b6dcfSDavid Howells	  module DOES NOT get stripped after being signed.  This includes the
1665ea0b6dcfSDavid Howells	  debuginfo strip done by some packagers (such as rpmbuild) and
1666ea0b6dcfSDavid Howells	  inclusion into an initramfs that wants the module size reduced.
1667ea0b6dcfSDavid Howells
1668106a4ee2SRusty Russellconfig MODULE_SIG_FORCE
1669106a4ee2SRusty Russell	bool "Require modules to be validly signed"
1670106a4ee2SRusty Russell	depends on MODULE_SIG
1671106a4ee2SRusty Russell	help
1672106a4ee2SRusty Russell	  Reject unsigned modules or signed modules for which we don't have a
1673106a4ee2SRusty Russell	  key.  Without this, such modules will simply taint the kernel.
1674ea0b6dcfSDavid Howells
1675ea0b6dcfSDavid Howellschoice
1676ea0b6dcfSDavid Howells	prompt "Which hash algorithm should modules be signed with?"
1677ea0b6dcfSDavid Howells	depends on MODULE_SIG
1678ea0b6dcfSDavid Howells	help
1679ea0b6dcfSDavid Howells	  This determines which sort of hashing algorithm will be used during
1680ea0b6dcfSDavid Howells	  signature generation.  This algorithm _must_ be built into the kernel
1681ea0b6dcfSDavid Howells	  directly so that signature verification can take place.  It is not
1682ea0b6dcfSDavid Howells	  possible to load a signed module containing the algorithm to check
1683ea0b6dcfSDavid Howells	  the signature on that module.
1684ea0b6dcfSDavid Howells
1685ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA1
1686ea0b6dcfSDavid Howells	bool "Sign modules with SHA-1"
1687ea0b6dcfSDavid Howells	select CRYPTO_SHA1
1688ea0b6dcfSDavid Howells
1689ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA224
1690ea0b6dcfSDavid Howells	bool "Sign modules with SHA-224"
1691ea0b6dcfSDavid Howells	select CRYPTO_SHA256
1692ea0b6dcfSDavid Howells
1693ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA256
1694ea0b6dcfSDavid Howells	bool "Sign modules with SHA-256"
1695ea0b6dcfSDavid Howells	select CRYPTO_SHA256
1696ea0b6dcfSDavid Howells
1697ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA384
1698ea0b6dcfSDavid Howells	bool "Sign modules with SHA-384"
1699ea0b6dcfSDavid Howells	select CRYPTO_SHA512
1700ea0b6dcfSDavid Howells
1701ea0b6dcfSDavid Howellsconfig MODULE_SIG_SHA512
1702ea0b6dcfSDavid Howells	bool "Sign modules with SHA-512"
1703ea0b6dcfSDavid Howells	select CRYPTO_SHA512
1704ea0b6dcfSDavid Howells
1705ea0b6dcfSDavid Howellsendchoice
1706ea0b6dcfSDavid Howells
17070b0de144SRobert P. J. Dayendif # MODULES
17080b0de144SRobert P. J. Day
170998a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE
171098a79d6aSRusty Russell	bool
171198a79d6aSRusty Russell	help
17125f054e31SRusty Russell	  Back when each arch used to define their own cpu_online_mask and
17135f054e31SRusty Russell	  cpu_possible_mask, some of them chose to initialize cpu_possible_mask
171498a79d6aSRusty Russell	  with all 1s, and others with all 0s.  When they were centralised,
171598a79d6aSRusty Russell	  it was better to provide this option than to break all the archs
1716692105b8SMatt LaPlante	  and have several arch maintainers pursuing me down dark alleys.
171798a79d6aSRusty Russell
17181da177e4SLinus Torvaldsconfig STOP_MACHINE
17191da177e4SLinus Torvalds	bool
17201da177e4SLinus Torvalds	default y
17211da177e4SLinus Torvalds	depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
17221da177e4SLinus Torvalds	help
17231da177e4SLinus Torvalds	  Need stop_machine() primitive.
17243a65dfe8SJens Axboe
17253a65dfe8SJens Axboesource "block/Kconfig"
1726e98c3202SAvi Kivity
1727e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS
1728e98c3202SAvi Kivity	bool
1729e260be67SPaul E. McKenney
173016295becSSteffen Klassertconfig PADATA
173116295becSSteffen Klassert	depends on SMP
173216295becSSteffen Klassert	bool
173316295becSSteffen Klassert
1734754b7b63SAndi Kleen# Can be selected by architectures with broken toolchains
1735754b7b63SAndi Kleen# that get confused by correct const<->read_only section
1736754b7b63SAndi Kleen# mappings
1737754b7b63SAndi Kleenconfig BROKEN_RODATA
1738754b7b63SAndi Kleen	bool
1739754b7b63SAndi Kleen
17404520c6a4SDavid Howellsconfig ASN1
17414520c6a4SDavid Howells	tristate
17424520c6a4SDavid Howells	help
17434520c6a4SDavid Howells	  Build a simple ASN.1 grammar compiler that produces a bytecode output
17444520c6a4SDavid Howells	  that can be interpreted by the ASN.1 stream decoder and used to
17454520c6a4SDavid Howells	  inform it as to what tags are to be expected in a stream and what
17464520c6a4SDavid Howells	  functions to call on what tags.
17474520c6a4SDavid Howells
17486beb0009SThomas Gleixnersource "kernel/Kconfig.locks"
1749