Kconfig 59.1 KB
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config ARCH
	string
	option env="ARCH"

config KERNELVERSION
	string
	option env="KERNELVERSION"

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config DEFCONFIG_LIST
	string
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	depends on !UML
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	option defconfig_list
	default "/lib/modules/$UNAME_RELEASE/.config"
	default "/etc/kernel-config"
	default "/boot/config-$UNAME_RELEASE"
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	default "$ARCH_DEFCONFIG"
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	default "arch/$ARCH/defconfig"

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config CONSTRUCTORS
	bool
	depends on !UML

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config IRQ_WORK
	bool

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config BUILDTIME_EXTABLE_SORT
	bool

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config THREAD_INFO_IN_TASK
	bool
	help
	  Select this to move thread_info off the stack into task_struct.  To
	  make this work, an arch will need to remove all thread_info fields
	  except flags and fix any runtime bugs.

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	  One subtle change that will be needed is to use try_get_task_stack()
	  and put_task_stack() in save_thread_stack_tsk() and get_wchan().

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menu "General setup"
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config BROKEN
	bool

config BROKEN_ON_SMP
	bool
	depends on BROKEN || !SMP
	default y

config INIT_ENV_ARG_LIMIT
	int
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	default 32 if !UML
	default 128 if UML
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	help
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	  Maximum of each of the number of arguments and environment
	  variables passed to init from the kernel command line.
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config CROSS_COMPILE
	string "Cross-compiler tool prefix"
	help
	  Same as running 'make CROSS_COMPILE=prefix-' but stored for
	  default make runs in this kernel build directory.  You don't
	  need to set this unless you want the configured kernel build
	  directory to select the cross-compiler automatically.

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config COMPILE_TEST
	bool "Compile also drivers which will not load"
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	depends on !UML
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	default n
	help
	  Some drivers can be compiled on a different platform than they are
	  intended to be run on. Despite they cannot be loaded there (or even
	  when they load they cannot be used due to missing HW support),
	  developers still, opposing to distributors, might want to build such
	  drivers to compile-test them.

	  If you are a developer and want to build everything available, say Y
	  here. If you are a user/distributor, say N here to exclude useless
	  drivers to be distributed.

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config LOCALVERSION
	string "Local version - append to kernel release"
	help
	  Append an extra string to the end of your kernel version.
	  This will show up when you type uname, for example.
	  The string you set here will be appended after the contents of
	  any files with a filename matching localversion* in your
	  object and source tree, in that order.  Your total string can
	  be a maximum of 64 characters.

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config LOCALVERSION_AUTO
	bool "Automatically append version information to the version string"
	default y
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	depends on !COMPILE_TEST
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	help
	  This will try to automatically determine if the current tree is a
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	  release tree by looking for git tags that belong to the current
	  top of tree revision.
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	  A string of the format -gxxxxxxxx will be added to the localversion
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	  if a git-based tree is found.  The string generated by this will be
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	  appended after any matching localversion* files, and after the value
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	  set in CONFIG_LOCALVERSION.
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	  (The actual string used here is the first eight characters produced
	  by running the command:

	    $ git rev-parse --verify HEAD

	  which is done within the script "scripts/setlocalversion".)
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config HAVE_KERNEL_GZIP
	bool

config HAVE_KERNEL_BZIP2
	bool

config HAVE_KERNEL_LZMA
	bool

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config HAVE_KERNEL_XZ
	bool

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config HAVE_KERNEL_LZO
	bool

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config HAVE_KERNEL_LZ4
	bool

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choice
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	prompt "Kernel compression mode"
	default KERNEL_GZIP
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	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
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	help
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	  The linux kernel is a kind of self-extracting executable.
	  Several compression algorithms are available, which differ
	  in efficiency, compression and decompression speed.
	  Compression speed is only relevant when building a kernel.
	  Decompression speed is relevant at each boot.

	  If you have any problems with bzip2 or lzma compressed
	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
	  version of this functionality (bzip2 only), for 2.4, was
	  supplied by Christian Ludwig)

	  High compression options are mostly useful for users, who
	  are low on disk space (embedded systems), but for whom ram
	  size matters less.

	  If in doubt, select 'gzip'

config KERNEL_GZIP
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	bool "Gzip"
	depends on HAVE_KERNEL_GZIP
	help
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	  The old and tried gzip compression. It provides a good balance
	  between compression ratio and decompression speed.
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config KERNEL_BZIP2
	bool "Bzip2"
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	depends on HAVE_KERNEL_BZIP2
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	help
	  Its compression ratio and speed is intermediate.
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	  Decompression speed is slowest among the choices.  The kernel
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	  size is about 10% smaller with bzip2, in comparison to gzip.
	  Bzip2 uses a large amount of memory. For modern kernels you
	  will need at least 8MB RAM or more for booting.
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config KERNEL_LZMA
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	bool "LZMA"
	depends on HAVE_KERNEL_LZMA
	help
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	  This compression algorithm's ratio is best.  Decompression speed
	  is between gzip and bzip2.  Compression is slowest.
	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
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config KERNEL_XZ
	bool "XZ"
	depends on HAVE_KERNEL_XZ
	help
	  XZ uses the LZMA2 algorithm and instruction set specific
	  BCJ filters which can improve compression ratio of executable
	  code. The size of the kernel is about 30% smaller with XZ in
	  comparison to gzip. On architectures for which there is a BCJ
	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
	  will create a few percent smaller kernel than plain LZMA.

	  The speed is about the same as with LZMA: The decompression
	  speed of XZ is better than that of bzip2 but worse than gzip
	  and LZO. Compression is slow.

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config KERNEL_LZO
	bool "LZO"
	depends on HAVE_KERNEL_LZO
	help
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	  Its compression ratio is the poorest among the choices. The kernel
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	  size is about 10% bigger than gzip; however its speed
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	  (both compression and decompression) is the fastest.

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config KERNEL_LZ4
	bool "LZ4"
	depends on HAVE_KERNEL_LZ4
	help
	  LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
	  A preliminary version of LZ4 de/compression tool is available at
	  <https://code.google.com/p/lz4/>.

	  Its compression ratio is worse than LZO. The size of the kernel
	  is about 8% bigger than LZO. But the decompression speed is
	  faster than LZO.

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endchoice

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config DEFAULT_HOSTNAME
	string "Default hostname"
	default "(none)"
	help
	  This option determines the default system hostname before userspace
	  calls sethostname(2). The kernel traditionally uses "(none)" here,
	  but you may wish to use a different default here to make a minimal
	  system more usable with less configuration.

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config SWAP
	bool "Support for paging of anonymous memory (swap)"
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	depends on MMU && BLOCK
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	default y
	help
	  This option allows you to choose whether you want to have support
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	  for so called swap devices or swap files in your kernel that are
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	  used to provide more virtual memory than the actual RAM present
	  in your computer.  If unsure say Y.

config SYSVIPC
	bool "System V IPC"
	---help---
	  Inter Process Communication is a suite of library functions and
	  system calls which let processes (running programs) synchronize and
	  exchange information. It is generally considered to be a good thing,
	  and some programs won't run unless you say Y here. In particular, if
	  you want to run the DOS emulator dosemu under Linux (read the
	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
	  you'll need to say Y here.

	  You can find documentation about IPC with "info ipc" and also in
	  section 6.4 of the Linux Programmer's Guide, available from
	  <http://www.tldp.org/guides.html>.

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config SYSVIPC_SYSCTL
	bool
	depends on SYSVIPC
	depends on SYSCTL
	default y

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config POSIX_MQUEUE
	bool "POSIX Message Queues"
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	depends on NET
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	---help---
	  POSIX variant of message queues is a part of IPC. In POSIX message
	  queues every message has a priority which decides about succession
	  of receiving it by a process. If you want to compile and run
	  programs written e.g. for Solaris with use of its POSIX message
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	  queues (functions mq_*) say Y here.
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	  POSIX message queues are visible as a filesystem called 'mqueue'
	  and can be mounted somewhere if you want to do filesystem
	  operations on message queues.

	  If unsure, say Y.

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config POSIX_MQUEUE_SYSCTL
	bool
	depends on POSIX_MQUEUE
	depends on SYSCTL
	default y

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config CROSS_MEMORY_ATTACH
	bool "Enable process_vm_readv/writev syscalls"
	depends on MMU
	default y
	help
	  Enabling this option adds the system calls process_vm_readv and
	  process_vm_writev which allow a process with the correct privileges
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	  to directly read from or write to another process' address space.
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	  See the man page for more details.

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config FHANDLE
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	bool "open by fhandle syscalls" if EXPERT
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	select EXPORTFS
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	default y
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	help
	  If you say Y here, a user level program will be able to map
	  file names to handle and then later use the handle for
	  different file system operations. This is useful in implementing
	  userspace file servers, which now track files using handles instead
	  of names. The handle would remain the same even if file names
	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
	  syscalls.

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config USELIB
	bool "uselib syscall"
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	def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
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	help
	  This option enables the uselib syscall, a system call used in the
	  dynamic linker from libc5 and earlier.  glibc does not use this
	  system call.  If you intend to run programs built on libc5 or
	  earlier, you may need to enable this syscall.  Current systems
	  running glibc can safely disable this.

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config AUDIT
	bool "Auditing support"
	depends on NET
	help
	  Enable auditing infrastructure that can be used with another
	  kernel subsystem, such as SELinux (which requires this for
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	  logging of avc messages output).  System call auditing is included
	  on architectures which support it.
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config HAVE_ARCH_AUDITSYSCALL
	bool

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config AUDITSYSCALL
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	def_bool y
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	depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
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config AUDIT_WATCH
	def_bool y
	depends on AUDITSYSCALL
	select FSNOTIFY

config AUDIT_TREE
	def_bool y
	depends on AUDITSYSCALL
	select FSNOTIFY

source "kernel/irq/Kconfig"
source "kernel/time/Kconfig"

menu "CPU/Task time and stats accounting"

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config VIRT_CPU_ACCOUNTING
	bool

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choice
	prompt "Cputime accounting"
	default TICK_CPU_ACCOUNTING if !PPC64
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	default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
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# Kind of a stub config for the pure tick based cputime accounting
config TICK_CPU_ACCOUNTING
	bool "Simple tick based cputime accounting"
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	depends on !S390 && !NO_HZ_FULL
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	help
	  This is the basic tick based cputime accounting that maintains
	  statistics about user, system and idle time spent on per jiffies
	  granularity.

	  If unsure, say Y.

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config VIRT_CPU_ACCOUNTING_NATIVE
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	bool "Deterministic task and CPU time accounting"
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	depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
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	select VIRT_CPU_ACCOUNTING
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	help
	  Select this option to enable more accurate task and CPU time
	  accounting.  This is done by reading a CPU counter on each
	  kernel entry and exit and on transitions within the kernel
	  between system, softirq and hardirq state, so there is a
	  small performance impact.  In the case of s390 or IBM POWER > 5,
	  this also enables accounting of stolen time on logically-partitioned
	  systems.

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config VIRT_CPU_ACCOUNTING_GEN
	bool "Full dynticks CPU time accounting"
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	depends on HAVE_CONTEXT_TRACKING
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	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
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	select VIRT_CPU_ACCOUNTING
	select CONTEXT_TRACKING
	help
	  Select this option to enable task and CPU time accounting on full
	  dynticks systems. This accounting is implemented by watching every
	  kernel-user boundaries using the context tracking subsystem.
	  The accounting is thus performed at the expense of some significant
	  overhead.

	  For now this is only useful if you are working on the full
	  dynticks subsystem development.

	  If unsure, say N.

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endchoice

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config IRQ_TIME_ACCOUNTING
	bool "Fine granularity task level IRQ time accounting"
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	depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
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	help
	  Select this option to enable fine granularity task irq time
	  accounting. This is done by reading a timestamp on each
	  transitions between softirq and hardirq state, so there can be a
	  small performance impact.

	  If in doubt, say N here.

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config BSD_PROCESS_ACCT
	bool "BSD Process Accounting"
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	depends on MULTIUSER
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	help
	  If you say Y here, a user level program will be able to instruct the
	  kernel (via a special system call) to write process accounting
	  information to a file: whenever a process exits, information about
	  that process will be appended to the file by the kernel.  The
	  information includes things such as creation time, owning user,
	  command name, memory usage, controlling terminal etc. (the complete
	  list is in the struct acct in <file:include/linux/acct.h>).  It is
	  up to the user level program to do useful things with this
	  information.  This is generally a good idea, so say Y.

config BSD_PROCESS_ACCT_V3
	bool "BSD Process Accounting version 3 file format"
	depends on BSD_PROCESS_ACCT
	default n
	help
	  If you say Y here, the process accounting information is written
	  in a new file format that also logs the process IDs of each
	  process and it's parent. Note that this file format is incompatible
	  with previous v0/v1/v2 file formats, so you will need updated tools
	  for processing it. A preliminary version of these tools is available
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	  at <http://www.gnu.org/software/acct/>.
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config TASKSTATS
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	bool "Export task/process statistics through netlink"
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	depends on NET
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	depends on MULTIUSER
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	default n
	help
	  Export selected statistics for tasks/processes through the
	  generic netlink interface. Unlike BSD process accounting, the
	  statistics are available during the lifetime of tasks/processes as
	  responses to commands. Like BSD accounting, they are sent to user
	  space on task exit.

	  Say N if unsure.

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config TASK_DELAY_ACCT
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	bool "Enable per-task delay accounting"
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	depends on TASKSTATS
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	select SCHED_INFO
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	help
	  Collect information on time spent by a task waiting for system
	  resources like cpu, synchronous block I/O completion and swapping
	  in pages. Such statistics can help in setting a task's priorities
	  relative to other tasks for cpu, io, rss limits etc.

	  Say N if unsure.

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config TASK_XACCT
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	bool "Enable extended accounting over taskstats"
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	depends on TASKSTATS
	help
	  Collect extended task accounting data and send the data
	  to userland for processing over the taskstats interface.

	  Say N if unsure.

config TASK_IO_ACCOUNTING
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	bool "Enable per-task storage I/O accounting"
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	depends on TASK_XACCT
	help
	  Collect information on the number of bytes of storage I/O which this
	  task has caused.

	  Say N if unsure.

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endmenu # "CPU/Task time and stats accounting"
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config CPU_ISOLATION
	bool "CPU isolation"
	help
	  Make sure that CPUs running critical tasks are not disturbed by
	  any source of "noise" such as unbound workqueues, timers, kthreads...
	  Unbound jobs get offloaded to housekeeping CPUs.

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source "kernel/rcu/Kconfig"
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config BUILD_BIN2C
	bool
	default n

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config IKCONFIG
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	tristate "Kernel .config support"
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	select BUILD_BIN2C
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	---help---
	  This option enables the complete Linux kernel ".config" file
	  contents to be saved in the kernel. It provides documentation
	  of which kernel options are used in a running kernel or in an
	  on-disk kernel.  This information can be extracted from the kernel
	  image file with the script scripts/extract-ikconfig and used as
	  input to rebuild the current kernel or to build another kernel.
	  It can also be extracted from a running kernel by reading
	  /proc/config.gz if enabled (below).

config IKCONFIG_PROC
	bool "Enable access to .config through /proc/config.gz"
	depends on IKCONFIG && PROC_FS
	---help---
	  This option enables access to the kernel configuration file
	  through /proc/config.gz.

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config LOG_BUF_SHIFT
	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
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	range 12 25
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	default 17
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	depends on PRINTK
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	help
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	  Select the minimal kernel log buffer size as a power of 2.
	  The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
	  parameter, see below. Any higher size also might be forced
	  by "log_buf_len" boot parameter.

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	  Examples:
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		     17 => 128 KB
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		     16 => 64 KB
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		     15 => 32 KB
		     14 => 16 KB
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		     13 =>  8 KB
		     12 =>  4 KB

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config LOG_CPU_MAX_BUF_SHIFT
	int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
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	depends on SMP
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	range 0 21
	default 12 if !BASE_SMALL
	default 0 if BASE_SMALL
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	depends on PRINTK
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	help
	  This option allows to increase the default ring buffer size
	  according to the number of CPUs. The value defines the contribution
	  of each CPU as a power of 2. The used space is typically only few
	  lines however it might be much more when problems are reported,
	  e.g. backtraces.

	  The increased size means that a new buffer has to be allocated and
	  the original static one is unused. It makes sense only on systems
	  with more CPUs. Therefore this value is used only when the sum of
	  contributions is greater than the half of the default kernel ring
	  buffer as defined by LOG_BUF_SHIFT. The default values are set
	  so that more than 64 CPUs are needed to trigger the allocation.

	  Also this option is ignored when "log_buf_len" kernel parameter is
	  used as it forces an exact (power of two) size of the ring buffer.

	  The number of possible CPUs is used for this computation ignoring
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	  hotplugging making the computation optimal for the worst case
	  scenario while allowing a simple algorithm to be used from bootup.
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	  Examples shift values and their meaning:
		     17 => 128 KB for each CPU
		     16 =>  64 KB for each CPU
		     15 =>  32 KB for each CPU
		     14 =>  16 KB for each CPU
		     13 =>   8 KB for each CPU
		     12 =>   4 KB for each CPU

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config PRINTK_SAFE_LOG_BUF_SHIFT
	int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
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	range 10 21
	default 13
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	depends on PRINTK
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	help
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	  Select the size of an alternate printk per-CPU buffer where messages
	  printed from usafe contexts are temporary stored. One example would
	  be NMI messages, another one - printk recursion. The messages are
	  copied to the main log buffer in a safe context to avoid a deadlock.
	  The value defines the size as a power of 2.
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	  Those messages are rare and limited. The largest one is when
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	  a backtrace is printed. It usually fits into 4KB. Select
	  8KB if you want to be on the safe side.

	  Examples:
		     17 => 128 KB for each CPU
		     16 =>  64 KB for each CPU
		     15 =>  32 KB for each CPU
		     14 =>  16 KB for each CPU
		     13 =>   8 KB for each CPU
		     12 =>   4 KB for each CPU

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#
# Architectures with an unreliable sched_clock() should select this:
#
config HAVE_UNSTABLE_SCHED_CLOCK
	bool

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config GENERIC_SCHED_CLOCK
	bool

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#
# For architectures that want to enable the support for NUMA-affine scheduler
# balancing logic:
#
config ARCH_SUPPORTS_NUMA_BALANCING
	bool

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#
# For architectures that prefer to flush all TLBs after a number of pages
# are unmapped instead of sending one IPI per page to flush. The architecture
# must provide guarantees on what happens if a clean TLB cache entry is
# written after the unmap. Details are in mm/rmap.c near the check for
# should_defer_flush. The architecture should also consider if the full flush
# and the refill costs are offset by the savings of sending fewer IPIs.
config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
	bool

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#
# For architectures that know their GCC __int128 support is sound
#
config ARCH_SUPPORTS_INT128
	bool

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# For architectures that (ab)use NUMA to represent different memory regions
# all cpu-local but of different latencies, such as SuperH.
#
config ARCH_WANT_NUMA_VARIABLE_LOCALITY
	bool

config NUMA_BALANCING
	bool "Memory placement aware NUMA scheduler"
	depends on ARCH_SUPPORTS_NUMA_BALANCING
	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
	depends on SMP && NUMA && MIGRATION
	help
	  This option adds support for automatic NUMA aware memory/task placement.
	  The mechanism is quite primitive and is based on migrating memory when
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	  it has references to the node the task is running on.
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	  This system will be inactive on UMA systems.

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config NUMA_BALANCING_DEFAULT_ENABLED
	bool "Automatically enable NUMA aware memory/task placement"
	default y
	depends on NUMA_BALANCING
	help
	  If set, automatic NUMA balancing will be enabled if running on a NUMA
	  machine.

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menuconfig CGROUPS
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	bool "Control Group support"
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	select KERNFS
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	help
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	  This option adds support for grouping sets of processes together, for
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	  use with process control subsystems such as Cpusets, CFS, memory
	  controls or device isolation.
	  See
		- Documentation/scheduler/sched-design-CFS.txt	(CFS)
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		- Documentation/cgroup-v1/ (features for grouping, isolation
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					  and resource control)
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	  Say N if unsure.

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if CGROUPS

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config PAGE_COUNTER
       bool

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config MEMCG
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	bool "Memory controller"
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	select PAGE_COUNTER
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	select EVENTFD
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	help
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	  Provides control over the memory footprint of tasks in a cgroup.
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config MEMCG_SWAP
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	bool "Swap controller"
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	depends on MEMCG && SWAP
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	help
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	  Provides control over the swap space consumed by tasks in a cgroup.

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config MEMCG_SWAP_ENABLED
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	bool "Swap controller enabled by default"
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	depends on MEMCG_SWAP
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	default y
	help
	  Memory Resource Controller Swap Extension comes with its price in
	  a bigger memory consumption. General purpose distribution kernels
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	  which want to enable the feature but keep it disabled by default
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	  and let the user enable it by swapaccount=1 boot command line
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	  parameter should have this option unselected.
	  For those who want to have the feature enabled by default should
	  select this option (if, for some reason, they need to disable it
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	  then swapaccount=0 does the trick).
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config BLK_CGROUP
	bool "IO controller"
	depends on BLOCK
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	default n
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	---help---
	Generic block IO controller cgroup interface. This is the common
	cgroup interface which should be used by various IO controlling
	policies.
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	Currently, CFQ IO scheduler uses it to recognize task groups and
	control disk bandwidth allocation (proportional time slice allocation)
	to such task groups. It is also used by bio throttling logic in
	block layer to implement upper limit in IO rates on a device.
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	This option only enables generic Block IO controller infrastructure.
	One needs to also enable actual IO controlling logic/policy. For
	enabling proportional weight division of disk bandwidth in CFQ, set
	CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
	CONFIG_BLK_DEV_THROTTLING=y.

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	See Documentation/cgroup-v1/blkio-controller.txt for more information.
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config DEBUG_BLK_CGROUP
	bool "IO controller debugging"
	depends on BLK_CGROUP
	default n
	---help---
	Enable some debugging help. Currently it exports additional stat
	files in a cgroup which can be useful for debugging.

config CGROUP_WRITEBACK
	bool
	depends on MEMCG && BLK_CGROUP
	default y
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menuconfig CGROUP_SCHED
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	bool "CPU controller"
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	default n
	help
	  This feature lets CPU scheduler recognize task groups and control CPU
	  bandwidth allocation to such task groups. It uses cgroups to group
	  tasks.

if CGROUP_SCHED
config FAIR_GROUP_SCHED
	bool "Group scheduling for SCHED_OTHER"
	depends on CGROUP_SCHED
	default CGROUP_SCHED

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config CFS_BANDWIDTH
	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
	depends on FAIR_GROUP_SCHED
	default n
	help
	  This option allows users to define CPU bandwidth rates (limits) for
	  tasks running within the fair group scheduler.  Groups with no limit
	  set are considered to be unconstrained and will run with no
	  restriction.
	  See tip/Documentation/scheduler/sched-bwc.txt for more information.

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config RT_GROUP_SCHED
	bool "Group scheduling for SCHED_RR/FIFO"
	depends on CGROUP_SCHED
	default n
	help
	  This feature lets you explicitly allocate real CPU bandwidth
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	  to task groups. If enabled, it will also make it impossible to
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	  schedule realtime tasks for non-root users until you allocate
	  realtime bandwidth for them.
	  See Documentation/scheduler/sched-rt-group.txt for more information.

endif #CGROUP_SCHED

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config CGROUP_PIDS
	bool "PIDs controller"
	help
	  Provides enforcement of process number limits in the scope of a
	  cgroup. Any attempt to fork more processes than is allowed in the
	  cgroup will fail. PIDs are fundamentally a global resource because it
	  is fairly trivial to reach PID exhaustion before you reach even a
	  conservative kmemcg limit. As a result, it is possible to grind a
	  system to halt without being limited by other cgroup policies. The
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	  PIDs controller is designed to stop this from happening.
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	  It should be noted that organisational operations (such as attaching
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	  to a cgroup hierarchy will *not* be blocked by the PIDs controller),
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	  since the PIDs limit only affects a process's ability to fork, not to
	  attach to a cgroup.

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config CGROUP_RDMA
	bool "RDMA controller"
	help
	  Provides enforcement of RDMA resources defined by IB stack.
	  It is fairly easy for consumers to exhaust RDMA resources, which
	  can result into resource unavailability to other consumers.
	  RDMA controller is designed to stop this from happening.
	  Attaching processes with active RDMA resources to the cgroup
	  hierarchy is allowed even if can cross the hierarchy's limit.

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config CGROUP_FREEZER
	bool "Freezer controller"
	help
	  Provides a way to freeze and unfreeze all tasks in a
	  cgroup.

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	  This option affects the ORIGINAL cgroup interface. The cgroup2 memory
	  controller includes important in-kernel memory consumers per default.

	  If you're using cgroup2, say N.

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config CGROUP_HUGETLB
	bool "HugeTLB controller"
	depends on HUGETLB_PAGE
	select PAGE_COUNTER
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	default n
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	help
	  Provides a cgroup controller for HugeTLB pages.
	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
	  The limit is enforced during page fault. Since HugeTLB doesn't
	  support page reclaim, enforcing the limit at page fault time implies
	  that, the application will get SIGBUS signal if it tries to access
	  HugeTLB pages beyond its limit. This requires the application to know
	  beforehand how much HugeTLB pages it would require for its use. The
	  control group is tracked in the third page lru pointer. This means
	  that we cannot use the controller with huge page less than 3 pages.
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config CPUSETS
	bool "Cpuset controller"
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	depends on SMP
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	help
	  This option will let you create and manage CPUSETs which
	  allow dynamically partitioning a system into sets of CPUs and
	  Memory Nodes and assigning tasks to run only within those sets.
	  This is primarily useful on large SMP or NUMA systems.
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	  Say N if unsure.
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config PROC_PID_CPUSET
	bool "Include legacy /proc/<pid>/cpuset file"
	depends on CPUSETS
	default y
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config CGROUP_DEVICE
	bool "Device controller"
	help
	  Provides a cgroup controller implementing whitelists for
	  devices which a process in the cgroup can mknod or open.

config CGROUP_CPUACCT
	bool "Simple CPU accounting controller"
	help
	  Provides a simple controller for monitoring the
	  total CPU consumed by the tasks in a cgroup.

config CGROUP_PERF
	bool "Perf controller"
	depends on PERF_EVENTS
	help
	  This option extends the perf per-cpu mode to restrict monitoring
	  to threads which belong to the cgroup specified and run on the
	  designated cpu.

	  Say N if unsure.

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config CGROUP_BPF
	bool "Support for eBPF programs attached to cgroups"
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	depends on BPF_SYSCALL
	select SOCK_CGROUP_DATA
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	help
	  Allow attaching eBPF programs to a cgroup using the bpf(2)
	  syscall command BPF_PROG_ATTACH.

	  In which context these programs are accessed depends on the type
	  of attachment. For instance, programs that are attached using
	  BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
	  inet sockets.

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config CGROUP_DEBUG
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	bool "Debug controller"
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	default n
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	depends on DEBUG_KERNEL
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	help
	  This option enables a simple controller that exports
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	  debugging information about the cgroups framework. This
	  controller is for control cgroup debugging only. Its
	  interfaces are not stable.
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	  Say N.
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config SOCK_CGROUP_DATA
	bool
	default n

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endif # CGROUPS
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config CHECKPOINT_RESTORE
	bool "Checkpoint/restore support" if EXPERT
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	select PROC_CHILDREN
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	default n
	help
	  Enables additional kernel features in a sake of checkpoint/restore.
	  In particular it adds auxiliary prctl codes to setup process text,
	  data and heap segment sizes, and a few additional /proc filesystem
	  entries.

	  If unsure, say N here.

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menuconfig NAMESPACES
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	bool "Namespaces support" if EXPERT
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	depends on MULTIUSER
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	default !EXPERT
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	help
	  Provides the way to make tasks work with different objects using
	  the same id. For example same IPC id may refer to different objects
	  or same user id or pid may refer to different tasks when used in
	  different namespaces.

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if NAMESPACES

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config UTS_NS
	bool "UTS namespace"
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	default y
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	help
	  In this namespace tasks see different info provided with the
	  uname() system call

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config IPC_NS
	bool "IPC namespace"
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	depends on (SYSVIPC || POSIX_MQUEUE)
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	default y
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	help
	  In this namespace tasks work with IPC ids which correspond to
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	  different IPC objects in different namespaces.
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config USER_NS
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	bool "User namespace"
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	default n
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	help
	  This allows containers, i.e. vservers, to use user namespaces
	  to provide different user info for different servers.
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	  When user namespaces are enabled in the kernel it is
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	  recommended that the MEMCG option also be enabled and that
	  user-space use the memory control groups to limit the amount
	  of memory a memory unprivileged users can use.
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	  If unsure, say N.

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config PID_NS
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	bool "PID Namespaces"
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	default y
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	help
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	  Support process id namespaces.  This allows having multiple
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	  processes with the same pid as long as they are in different
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	  pid namespaces.  This is a building block of containers.

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config NET_NS
	bool "Network namespace"
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	depends on NET
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	default y
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	help
	  Allow user space to create what appear to be multiple instances
	  of the network stack.

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endif # NAMESPACES

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config SCHED_AUTOGROUP
	bool "Automatic process group scheduling"
	select CGROUPS
	select CGROUP_SCHED
	select FAIR_GROUP_SCHED
	help
	  This option optimizes the scheduler for common desktop workloads by
	  automatically creating and populating task groups.  This separation
	  of workloads isolates aggressive CPU burners (like build jobs) from
	  desktop applications.  Task group autogeneration is currently based
	  upon task session.

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config SYSFS_DEPRECATED
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	bool "Enable deprecated sysfs features to support old userspace tools"
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	depends on SYSFS
	default n
	help
	  This option adds code that switches the layout of the "block" class
	  devices, to not show up in /sys/class/block/, but only in
	  /sys/block/.

	  This switch is only active when the sysfs.deprecated=1 boot option is
	  passed or the SYSFS_DEPRECATED_V2 option is set.

	  This option allows new kernels to run on old distributions and tools,
	  which might get confused by /sys/class/block/. Since 2007/2008 all
	  major distributions and tools handle this just fine.

	  Recent distributions and userspace tools after 2009/2010 depend on
	  the existence of /sys/class/block/, and will not work with this
	  option enabled.

	  Only if you are using a new kernel on an old distribution, you might
	  need to say Y here.

config SYSFS_DEPRECATED_V2
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	bool "Enable deprecated sysfs features by default"
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	default n
	depends on SYSFS
	depends on SYSFS_DEPRECATED
	help
	  Enable deprecated sysfs by default.

	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
	  option.

	  Only if you are using a new kernel on an old distribution, you might
	  need to say Y here. Even then, odds are you would not need it
	  enabled, you can always pass the boot option if absolutely necessary.

config RELAY
	bool "Kernel->user space relay support (formerly relayfs)"
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	select IRQ_WORK
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	help
	  This option enables support for relay interface support in
	  certain file systems (such as debugfs).
	  It is designed to provide an efficient mechanism for tools and
	  facilities to relay large amounts of data from kernel space to
	  user space.

	  If unsure, say N.

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config BLK_DEV_INITRD
	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
	depends on BROKEN || !FRV
	help
	  The initial RAM filesystem is a ramfs which is loaded by the
	  boot loader (loadlin or lilo) and that is mounted as root
	  before the normal boot procedure. It is typically used to
	  load modules needed to mount the "real" root file system,
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	  etc. See <file:Documentation/admin-guide/initrd.rst> for details.
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	  If RAM disk support (BLK_DEV_RAM) is also included, this
	  also enables initial RAM disk (initrd) support and adds
	  15 Kbytes (more on some other architectures) to the kernel size.

	  If unsure say Y.

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if BLK_DEV_INITRD

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source "usr/Kconfig"

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endif

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choice
	prompt "Compiler optimization level"
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	default CC_OPTIMIZE_FOR_PERFORMANCE
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config CC_OPTIMIZE_FOR_PERFORMANCE
	bool "Optimize for performance"
	help
	  This is the default optimization level for the kernel, building
	  with the "-O2" compiler flag for best performance and most
	  helpful compile-time warnings.

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config CC_OPTIMIZE_FOR_SIZE
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	bool "Optimize for size"
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	help
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	  Enabling this option will pass "-Os" instead of "-O2" to
	  your compiler resulting in a smaller kernel.
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	  If unsure, say N.
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endchoice

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config SYSCTL
	bool

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config ANON_INODES
	bool

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config HAVE_UID16
	bool

config SYSCTL_EXCEPTION_TRACE
	bool
	help
	  Enable support for /proc/sys/debug/exception-trace.

config SYSCTL_ARCH_UNALIGN_NO_WARN
	bool
	help
	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
	  Allows arch to define/use @no_unaligned_warning to possibly warn
	  about unaligned access emulation going on under the hood.

config SYSCTL_ARCH_UNALIGN_ALLOW
	bool
	help
	  Enable support for /proc/sys/kernel/unaligned-trap
	  Allows arches to define/use @unaligned_enabled to runtime toggle
	  the unaligned access emulation.
	  see arch/parisc/kernel/unaligned.c for reference

config HAVE_PCSPKR_PLATFORM
	bool

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# interpreter that classic socket filters depend on
config BPF
	bool

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menuconfig EXPERT
	bool "Configure standard kernel features (expert users)"
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	# Unhide debug options, to make the on-by-default options visible
	select DEBUG_KERNEL
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	help
	  This option allows certain base kernel options and settings
          to be disabled or tweaked. This is for specialized
          environments which can tolerate a "non-standard" kernel.
          Only use this if you really know what you are doing.

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config UID16
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	bool "Enable 16-bit UID system calls" if EXPERT
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	depends on HAVE_UID16 && MULTIUSER
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	default y
	help
	  This enables the legacy 16-bit UID syscall wrappers.

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config MULTIUSER
	bool "Multiple users, groups and capabilities support" if EXPERT
	default y
	help
	  This option enables support for non-root users, groups and
	  capabilities.

	  If you say N here, all processes will run with UID 0, GID 0, and all
	  possible capabilities.  Saying N here also compiles out support for
	  system calls related to UIDs, GIDs, and capabilities, such as setuid,
	  setgid, and capset.

	  If unsure, say Y here.

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config SGETMASK_SYSCALL
	bool "sgetmask/ssetmask syscalls support" if EXPERT
	def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
	---help---
	  sys_sgetmask and sys_ssetmask are obsolete system calls
	  no longer supported in libc but still enabled by default in some
	  architectures.

	  If unsure, leave the default option here.

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config SYSFS_SYSCALL
	bool "Sysfs syscall support" if EXPERT
	default y
	---help---
	  sys_sysfs is an obsolete system call no longer supported in libc.
	  Note that disabling this option is more secure but might break
	  compatibility with some systems.

	  If unsure say Y here.

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config SYSCTL_SYSCALL
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	bool "Sysctl syscall support" if EXPERT
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	depends on PROC_SYSCTL
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	default n
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	select SYSCTL
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	---help---
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	  sys_sysctl uses binary paths that have been found challenging
	  to properly maintain and use.  The interface in /proc/sys
	  using paths with ascii names is now the primary path to this
	  information.
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	  Almost nothing using the binary sysctl interface so if you are
	  trying to save some space it is probably safe to disable this,
	  making your kernel marginally smaller.
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	  If unsure say N here.
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config POSIX_TIMERS
	bool "Posix Clocks & timers" if EXPERT
	default y
	help
	  This includes native support for POSIX timers to the kernel.
	  Some embedded systems have no use for them and therefore they
	  can be configured out to reduce the size of the kernel image.

	  When this option is disabled, the following syscalls won't be
	  available: timer_create, timer_gettime: timer_getoverrun,
	  timer_settime, timer_delete, clock_adjtime, getitimer,
	  setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
	  clock_getres and clock_nanosleep syscalls will be limited to
	  CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.

	  If unsure say y.

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config KALLSYMS
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	 bool "Load all symbols for debugging/ksymoops" if EXPERT
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	 default y
	 help
	   Say Y here to let the kernel print out symbolic crash information and
	   symbolic stack backtraces. This increases the size of the kernel
	   somewhat, as all symbols have to be loaded into the kernel image.

config KALLSYMS_ALL
	bool "Include all symbols in kallsyms"
	depends on DEBUG_KERNEL && KALLSYMS
	help
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	   Normally kallsyms only contains the symbols of functions for nicer
	   OOPS messages and backtraces (i.e., symbols from the text and inittext
	   sections). This is sufficient for most cases. And only in very rare
	   cases (e.g., when a debugger is used) all symbols are required (e.g.,
	   names of variables from the data sections, etc).

	   This option makes sure that all symbols are loaded into the kernel
	   image (i.e., symbols from all sections) in cost of increased kernel
	   size (depending on the kernel configuration, it may be 300KiB or
	   something like this).

	   Say N unless you really need all symbols.
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config KALLSYMS_ABSOLUTE_PERCPU
	bool
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	depends on KALLSYMS
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	default X86_64 && SMP

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config KALLSYMS_BASE_RELATIVE
	bool
	depends on KALLSYMS
	default !IA64 && !(TILE && 64BIT)
	help
	  Instead of emitting them as absolute values in the native word size,
	  emit the symbol references in the kallsyms table as 32-bit entries,
	  each containing a relative value in the range [base, base + U32_MAX]
	  or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
	  an absolute value in the range [0, S32_MAX] or a relative value in the
	  range [base, base + S32_MAX], where base is the lowest relative symbol
	  address encountered in the image.

	  On 64-bit builds, this reduces the size of the address table by 50%,
	  but more importantly, it results in entries whose values are build
	  time constants, and no relocation pass is required at runtime to fix
	  up the entries based on the runtime load address of the kernel.

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config PRINTK
	default y
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	bool "Enable support for printk" if EXPERT
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	select IRQ_WORK
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	help
	  This option enables normal printk support. Removing it
	  eliminates most of the message strings from the kernel image
	  and makes the kernel more or less silent. As this makes it
	  very difficult to diagnose system problems, saying N here is
	  strongly discouraged.

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config PRINTK_NMI
	def_bool y
	depends on PRINTK
	depends on HAVE_NMI

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config BUG
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	bool "BUG() support" if EXPERT
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	default y
	help
          Disabling this option eliminates support for BUG and WARN, reducing
          the size of your kernel image and potentially quietly ignoring
          numerous fatal conditions. You should only consider disabling this
          option for embedded systems with no facilities for reporting errors.
          Just say Y.

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config ELF_CORE
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	depends on COREDUMP
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	default y
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	bool "Enable ELF core dumps" if EXPERT
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	help
	  Enable support for generating core dumps. Disabling saves about 4k.

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config PCSPKR_PLATFORM
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	bool "Enable PC-Speaker support" if EXPERT
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	depends on HAVE_PCSPKR_PLATFORM
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	select I8253_LOCK
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	default y
	help
          This option allows to disable the internal PC-Speaker
          support, saving some memory.

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config BASE_FULL
	default y
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	bool "Enable full-sized data structures for core" if EXPERT
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	help
	  Disabling this option reduces the size of miscellaneous core
	  kernel data structures. This saves memory on small machines,
	  but may reduce performance.

config FUTEX
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	bool "Enable futex support" if EXPERT
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	default y
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	imply RT_MUTEXES
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	help
	  Disabling this option will cause the kernel to be built without
	  support for "fast userspace mutexes".  The resulting kernel may not
	  run glibc-based applications correctly.

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config FUTEX_PI
	bool
	depends on FUTEX && RT_MUTEXES
	default y

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config HAVE_FUTEX_CMPXCHG
	bool
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	depends on FUTEX
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	help
	  Architectures should select this if futex_atomic_cmpxchg_inatomic()
	  is implemented and always working. This removes a couple of runtime
	  checks.

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config EPOLL
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	bool "Enable eventpoll support" if EXPERT
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	default y
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	select ANON_INODES
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	help
	  Disabling this option will cause the kernel to be built without
	  support for epoll family of system calls.

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config SIGNALFD
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	bool "Enable signalfd() system call" if EXPERT
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	select ANON_INODES
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	default y
	help
	  Enable the signalfd() system call that allows to receive signals
	  on a file descriptor.

	  If unsure, say Y.

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config TIMERFD
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	bool "Enable timerfd() system call" if EXPERT
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	select ANON_INODES
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	default y
	help
	  Enable the timerfd() system call that allows to receive timer
	  events on a file descriptor.

	  If unsure, say Y.

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config EVENTFD
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	bool "Enable eventfd() system call" if EXPERT
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	select ANON_INODES
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	default y
	help
	  Enable the eventfd() system call that allows to receive both
	  kernel notification (ie. KAIO) or userspace notifications.

	  If unsure, say Y.

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# syscall, maps, verifier
config BPF_SYSCALL
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	bool "Enable bpf() system call"
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	select ANON_INODES
	select BPF
	default n
	help
	  Enable the bpf() system call that allows to manipulate eBPF
	  programs and maps via file descriptors.

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config SHMEM
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	bool "Use full shmem filesystem" if EXPERT
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	default y
	depends on MMU
	help
	  The shmem is an internal filesystem used to manage shared memory.
	  It is backed by swap and manages resource limits. It is also exported
	  to userspace as tmpfs if TMPFS is enabled. Disabling this
	  option replaces shmem and tmpfs with the much simpler ramfs code,
	  which may be appropriate on small systems without swap.

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config AIO
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	bool "Enable AIO support" if EXPERT
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	default y
	help
	  This option enables POSIX asynchronous I/O which may by used
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	  by some high performance threaded applications. Disabling
	  this option saves about 7k.

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config ADVISE_SYSCALLS
	bool "Enable madvise/fadvise syscalls" if EXPERT
	default y
	help
	  This option enables the madvise and fadvise syscalls, used by
	  applications to advise the kernel about their future memory or file
	  usage, improving performance. If building an embedded system where no
	  applications use these syscalls, you can disable this option to save
	  space.

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config USERFAULTFD
	bool "Enable userfaultfd() system call"
	select ANON_INODES
	depends on MMU
	help
	  Enable the userfaultfd() system call that allows to intercept and
	  handle page faults in userland.

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config PCI_QUIRKS
	default y
	bool "Enable PCI quirk workarounds" if EXPERT
	depends on PCI
	help
	  This enables workarounds for various PCI chipset
	  bugs/quirks. Disable this only if your target machine is
	  unaffected by PCI quirks.
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config MEMBARRIER
	bool "Enable membarrier() system call" if EXPERT
	default y
	help
	  Enable the membarrier() system call that allows issuing memory
	  barriers across all running threads, which can be used to distribute
	  the cost of user-space memory barriers asymmetrically by transforming
	  pairs of memory barriers into pairs consisting of membarrier() and a
	  compiler barrier.

	  If unsure, say Y.

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config EMBEDDED
	bool "Embedded system"
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	option allnoconfig_y
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	select EXPERT
	help
	  This option should be enabled if compiling the kernel for
	  an embedded system so certain expert options are available
	  for configuration.

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config HAVE_PERF_EVENTS
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	bool
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	help
	  See tools/perf/design.txt for details.
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config PERF_USE_VMALLOC
	bool
	help
	  See tools/perf/design.txt for details

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config PC104
	bool "PC/104 support"
	help
	  Expose PC/104 form factor device drivers and options available for
	  selection and configuration. Enable this option if your target
	  machine has a PC/104 bus.

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menu "Kernel Performance Events And Counters"
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config PERF_EVENTS
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	bool "Kernel performance events and counters"
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	default y if PROFILING
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	depends on HAVE_PERF_EVENTS
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	select ANON_INODES
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	select IRQ_WORK
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	select SRCU
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	help
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	  Enable kernel support for various performance events provided
	  by software and hardware.
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	  Software events are supported either built-in or via the
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	  use of generic tracepoints.
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	  Most modern CPUs support performance events via performance
	  counter registers. These registers count the number of certain
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	  types of hw events: such as instructions executed, cachemisses
	  suffered, or branches mis-predicted - without slowing down the
	  kernel or applications. These registers can also trigger interrupts
	  when a threshold number of events have passed - and can thus be
	  used to profile the code that runs on that CPU.

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	  The Linux Performance Event subsystem provides an abstraction of
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	  these software and hardware event capabilities, available via a
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	  system call and used by the "perf" utility in tools/perf/. It
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	  provides per task and per CPU counters, and it provides event
	  capabilities on top of those.

	  Say Y if unsure.

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config DEBUG_PERF_USE_VMALLOC
	default n
	bool "Debug: use vmalloc to back perf mmap() buffers"
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	depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
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	select PERF_USE_VMALLOC
	help
	 Use vmalloc memory to back perf mmap() buffers.

	 Mostly useful for debugging the vmalloc code on platforms
	 that don't require it.

	 Say N if unsure.

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endmenu

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config VM_EVENT_COUNTERS
	default y
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	bool "Enable VM event counters for /proc/vmstat" if EXPERT
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	help
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	  VM event counters are needed for event counts to be shown.
	  This option allows the disabling of the VM event counters
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	  on EXPERT systems.  /proc/vmstat will only show page counts
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	  if VM event counters are disabled.
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config SLUB_DEBUG
	default y
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	bool "Enable SLUB debugging support" if EXPERT
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	depends on SLUB && SYSFS
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	help
	  SLUB has extensive debug support features. Disabling these can
	  result in significant savings in code size. This also disables
	  SLUB sysfs support. /sys/slab will not exist and there will be
	  no support for cache validation etc.

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