Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6.git] / init / Kconfig

config ARCH
        string
        option env="ARCH"

config KERNELVERSION
        string
        option env="KERNELVERSION"

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

config CONSTRUCTORS
        bool
        depends on !UML

config IRQ_WORK
        bool

config BUILDTIME_EXTABLE_SORT
        bool

menu "General setup"

config BROKEN
        bool

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

config INIT_ENV_ARG_LIMIT
        int
        default 32 if !UML
        default 128 if UML
        help
          Maximum of each of the number of arguments and environment
          variables passed to init from the kernel command line.


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.

config COMPILE_TEST
        bool "Compile also drivers which will not load"
        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.

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.

config LOCALVERSION_AUTO
        bool "Automatically append version information to the version string"
        default y
        help
          This will try to automatically determine if the current tree is a
          release tree by looking for git tags that belong to the current
          top of tree revision.

          A string of the format -gxxxxxxxx will be added to the localversion
          if a git-based tree is found.  The string generated by this will be
          appended after any matching localversion* files, and after the value
          set in CONFIG_LOCALVERSION.

          (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".)

config HAVE_KERNEL_GZIP
        bool

config HAVE_KERNEL_BZIP2
        bool

config HAVE_KERNEL_LZMA
        bool

config HAVE_KERNEL_XZ
        bool

config HAVE_KERNEL_LZO
        bool

config HAVE_KERNEL_LZ4
        bool

choice
        prompt "Kernel compression mode"
        default KERNEL_GZIP
        depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
        help
          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
        bool "Gzip"
        depends on HAVE_KERNEL_GZIP
        help
          The old and tried gzip compression. It provides a good balance
          between compression ratio and decompression speed.

config KERNEL_BZIP2
        bool "Bzip2"
        depends on HAVE_KERNEL_BZIP2
        help
          Its compression ratio and speed is intermediate.
          Decompression speed is slowest among the choices.  The kernel
          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.

config KERNEL_LZMA
        bool "LZMA"
        depends on HAVE_KERNEL_LZMA
        help
          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.

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.

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

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.

endchoice

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.

config SWAP
        bool "Support for paging of anonymous memory (swap)"
        depends on MMU && BLOCK
        default y
        help
          This option allows you to choose whether you want to have support
          for so called swap devices or swap files in your kernel that are
          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>.

config SYSVIPC_SYSCTL
        bool
        depends on SYSVIPC
        depends on SYSCTL
        default y

config POSIX_MQUEUE
        bool "POSIX Message Queues"
        depends on NET
        ---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
          queues (functions mq_*) say Y here.

          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.

config POSIX_MQUEUE_SYSCTL
        bool
        depends on POSIX_MQUEUE
        depends on SYSCTL
        default y

config FHANDLE
        bool "open by fhandle syscalls"
        select EXPORTFS
        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.

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
          logging of avc messages output).  Does not do system-call
          auditing without CONFIG_AUDITSYSCALL.

config AUDITSYSCALL
        bool "Enable system-call auditing support"
        depends on AUDIT && (X86 || PARISC || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
        default y if SECURITY_SELINUX
        help
          Enable low-overhead system-call auditing infrastructure that
          can be used independently or with another kernel subsystem,
          such as SELinux.

config AUDIT_WATCH
        def_bool y
        depends on AUDITSYSCALL
        select FSNOTIFY

config AUDIT_TREE
        def_bool y
        depends on AUDITSYSCALL
        select FSNOTIFY

config AUDIT_LOGINUID_IMMUTABLE
        bool "Make audit loginuid immutable"
        depends on AUDIT
        help
          The config option toggles if a task setting its loginuid requires
          CAP_SYS_AUDITCONTROL or if that task should require no special permissions
          but should instead only allow setting its loginuid if it was never
          previously set.  On systems which use systemd or a similar central
          process to restart login services this should be set to true.  On older
          systems in which an admin would typically have to directly stop and
          start processes this should be set to false.  Setting this to true allows
          one to drop potentially dangerous capabilites from the login tasks,
          but may not be backwards compatible with older init systems.

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

menu "CPU/Task time and stats accounting"

config VIRT_CPU_ACCOUNTING
        bool

choice
        prompt "Cputime accounting"
        default TICK_CPU_ACCOUNTING if !PPC64
        default VIRT_CPU_ACCOUNTING_NATIVE if PPC64

# Kind of a stub config for the pure tick based cputime accounting
config TICK_CPU_ACCOUNTING
        bool "Simple tick based cputime accounting"
        depends on !S390 && !NO_HZ_FULL
        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.

config VIRT_CPU_ACCOUNTING_NATIVE
        bool "Deterministic task and CPU time accounting"
        depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
        select VIRT_CPU_ACCOUNTING
        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.

config VIRT_CPU_ACCOUNTING_GEN
        bool "Full dynticks CPU time accounting"
        depends on HAVE_CONTEXT_TRACKING && 64BIT
        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.

config IRQ_TIME_ACCOUNTING
        bool "Fine granularity task level IRQ time accounting"
        depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
        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.

endchoice

config BSD_PROCESS_ACCT
        bool "BSD Process Accounting"
        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
          at <http://www.gnu.org/software/acct/>.

config TASKSTATS
        bool "Export task/process statistics through netlink"
        depends on NET
        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.

config TASK_DELAY_ACCT
        bool "Enable per-task delay accounting"
        depends on TASKSTATS
        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.

config TASK_XACCT
        bool "Enable extended accounting over taskstats"
        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
        bool "Enable per-task storage I/O accounting"
        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.

endmenu # "CPU/Task time and stats accounting"

menu "RCU Subsystem"

choice
        prompt "RCU Implementation"
        default TREE_RCU

config TREE_RCU
        bool "Tree-based hierarchical RCU"
        depends on !PREEMPT && SMP
        select IRQ_WORK
        help
          This option selects the RCU implementation that is
          designed for very large SMP system with hundreds or
          thousands of CPUs.  It also scales down nicely to
          smaller systems.

config TREE_PREEMPT_RCU
        bool "Preemptible tree-based hierarchical RCU"
        depends on PREEMPT
        select IRQ_WORK
        help
          This option selects the RCU implementation that is
          designed for very large SMP systems with hundreds or
          thousands of CPUs, but for which real-time response
          is also required.  It also scales down nicely to
          smaller systems.

          Select this option if you are unsure.

config TINY_RCU
        bool "UP-only small-memory-footprint RCU"
        depends on !PREEMPT && !SMP
        help
          This option selects the RCU implementation that is
          designed for UP systems from which real-time response
          is not required.  This option greatly reduces the
          memory footprint of RCU.

endchoice

config PREEMPT_RCU
        def_bool TREE_PREEMPT_RCU
        help
          This option enables preemptible-RCU code that is common between
          the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.

config RCU_STALL_COMMON
        def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
        help
          This option enables RCU CPU stall code that is common between
          the TINY and TREE variants of RCU.  The purpose is to allow
          the tiny variants to disable RCU CPU stall warnings, while
          making these warnings mandatory for the tree variants.

config CONTEXT_TRACKING
       bool

config RCU_USER_QS
        bool "Consider userspace as in RCU extended quiescent state"
        depends on HAVE_CONTEXT_TRACKING && SMP
        select CONTEXT_TRACKING
        help
          This option sets hooks on kernel / userspace boundaries and
          puts RCU in extended quiescent state when the CPU runs in
          userspace. It means that when a CPU runs in userspace, it is
          excluded from the global RCU state machine and thus doesn't
          try to keep the timer tick on for RCU.

          Unless you want to hack and help the development of the full
          dynticks mode, you shouldn't enable this option.  It also
          adds unnecessary overhead.

          If unsure say N

config CONTEXT_TRACKING_FORCE
        bool "Force context tracking"
        depends on CONTEXT_TRACKING
        default y if !NO_HZ_FULL
        help
          The major pre-requirement for full dynticks to work is to
          support the context tracking subsystem. But there are also
          other dependencies to provide in order to make the full
          dynticks working.

          This option stands for testing when an arch implements the
          context tracking backend but doesn't yet fullfill all the
          requirements to make the full dynticks feature working.
          Without the full dynticks, there is no way to test the support
          for context tracking and the subsystems that rely on it: RCU
          userspace extended quiescent state and tickless cputime
          accounting. This option copes with the absence of the full
          dynticks subsystem by forcing the context tracking on all
          CPUs in the system.

          Say Y only if you're working on the developpement of an
          architecture backend for the context tracking.

          Say N otherwise, this option brings an overhead that you
          don't want in production.


config RCU_FANOUT
        int "Tree-based hierarchical RCU fanout value"
        range 2 64 if 64BIT
        range 2 32 if !64BIT
        depends on TREE_RCU || TREE_PREEMPT_RCU
        default 64 if 64BIT
        default 32 if !64BIT
        help
          This option controls the fanout of hierarchical implementations
          of RCU, allowing RCU to work efficiently on machines with
          large numbers of CPUs.  This value must be at least the fourth
          root of NR_CPUS, which allows NR_CPUS to be insanely large.
          The default value of RCU_FANOUT should be used for production
          systems, but if you are stress-testing the RCU implementation
          itself, small RCU_FANOUT values allow you to test large-system
          code paths on small(er) systems.

          Select a specific number if testing RCU itself.
          Take the default if unsure.

config RCU_FANOUT_LEAF
        int "Tree-based hierarchical RCU leaf-level fanout value"
        range 2 RCU_FANOUT if 64BIT
        range 2 RCU_FANOUT if !64BIT
        depends on TREE_RCU || TREE_PREEMPT_RCU
        default 16
        help
          This option controls the leaf-level fanout of hierarchical
          implementations of RCU, and allows trading off cache misses
          against lock contention.  Systems that synchronize their
          scheduling-clock interrupts for energy-efficiency reasons will
          want the default because the smaller leaf-level fanout keeps
          lock contention levels acceptably low.  Very large systems
          (hundreds or thousands of CPUs) will instead want to set this
          value to the maximum value possible in order to reduce the
          number of cache misses incurred during RCU's grace-period
          initialization.  These systems tend to run CPU-bound, and thus
          are not helped by synchronized interrupts, and thus tend to
          skew them, which reduces lock contention enough that large
          leaf-level fanouts work well.

          Select a specific number if testing RCU itself.

          Select the maximum permissible value for large systems.

          Take the default if unsure.

config RCU_FANOUT_EXACT
        bool "Disable tree-based hierarchical RCU auto-balancing"
        depends on TREE_RCU || TREE_PREEMPT_RCU
        default n
        help
          This option forces use of the exact RCU_FANOUT value specified,
          regardless of imbalances in the hierarchy.  This is useful for
          testing RCU itself, and might one day be useful on systems with
          strong NUMA behavior.

          Without RCU_FANOUT_EXACT, the code will balance the hierarchy.

          Say N if unsure.

config RCU_FAST_NO_HZ
        bool "Accelerate last non-dyntick-idle CPU's grace periods"
        depends on NO_HZ_COMMON && SMP
        default n
        help
          This option permits CPUs to enter dynticks-idle state even if
          they have RCU callbacks queued, and prevents RCU from waking
          these CPUs up more than roughly once every four jiffies (by
          default, you can adjust this using the rcutree.rcu_idle_gp_delay
          parameter), thus improving energy efficiency.  On the other
          hand, this option increases the duration of RCU grace periods,
          for example, slowing down synchronize_rcu().

          Say Y if energy efficiency is critically important, and you
                don't care about increased grace-period durations.

          Say N if you are unsure.

config TREE_RCU_TRACE
        def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
        select DEBUG_FS
        help
          This option provides tracing for the TREE_RCU and
          TREE_PREEMPT_RCU implementations, permitting Makefile to
          trivially select kernel/rcutree_trace.c.

config RCU_BOOST
        bool "Enable RCU priority boosting"
        depends on RT_MUTEXES && PREEMPT_RCU
        default n
        help
          This option boosts the priority of preempted RCU readers that
          block the current preemptible RCU grace period for too long.
          This option also prevents heavy loads from blocking RCU
          callback invocation for all flavors of RCU.

          Say Y here if you are working with real-time apps or heavy loads
          Say N here if you are unsure.

config RCU_BOOST_PRIO
        int "Real-time priority to boost RCU readers to"
        range 1 99
        depends on RCU_BOOST
        default 1
        help
          This option specifies the real-time priority to which long-term
          preempted RCU readers are to be boosted.  If you are working
          with a real-time application that has one or more CPU-bound
          threads running at a real-time priority level, you should set
          RCU_BOOST_PRIO to a priority higher then the highest-priority
          real-time CPU-bound thread.  The default RCU_BOOST_PRIO value
          of 1 is appropriate in the common case, which is real-time
          applications that do not have any CPU-bound threads.

          Some real-time applications might not have a single real-time
          thread that saturates a given CPU, but instead might have
          multiple real-time threads that, taken together, fully utilize
          that CPU.  In this case, you should set RCU_BOOST_PRIO to
          a priority higher than the lowest-priority thread that is
          conspiring to prevent the CPU from running any non-real-time
          tasks.  For example, if one thread at priority 10 and another
          thread at priority 5 are between themselves fully consuming
          the CPU time on a given CPU, then RCU_BOOST_PRIO should be
          set to priority 6 or higher.

          Specify the real-time priority, or take the default if unsure.

config RCU_BOOST_DELAY
        int "Milliseconds to delay boosting after RCU grace-period start"
        range 0 3000
        depends on RCU_BOOST
        default 500
        help
          This option specifies the time to wait after the beginning of
          a given grace period before priority-boosting preempted RCU
          readers blocking that grace period.  Note that any RCU reader
          blocking an expedited RCU grace period is boosted immediately.

          Accept the default if unsure.

config RCU_NOCB_CPU
        bool "Offload RCU callback processing from boot-selected CPUs"
        depends on TREE_RCU || TREE_PREEMPT_RCU
        default n
        help
          Use this option to reduce OS jitter for aggressive HPC or
          real-time workloads.  It can also be used to offload RCU
          callback invocation to energy-efficient CPUs in battery-powered
          asymmetric multiprocessors.

          This option offloads callback invocation from the set of
          CPUs specified at boot time by the rcu_nocbs parameter.
          For each such CPU, a kthread ("rcuox/N") will be created to
          invoke callbacks, where the "N" is the CPU being offloaded,
          and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
          "s" for RCU-sched.  Nothing prevents this kthread from running
          on the specified CPUs, but (1) the kthreads may be preempted
          between each callback, and (2) affinity or cgroups can be used
          to force the kthreads to run on whatever set of CPUs is desired.

          Say Y here if you want to help to debug reduced OS jitter.
          Say N here if you are unsure.

choice
        prompt "Build-forced no-CBs CPUs"
        default RCU_NOCB_CPU_NONE
        help
          This option allows no-CBs CPUs (whose RCU callbacks are invoked
          from kthreads rather than from softirq context) to be specified
          at build time.  Additional no-CBs CPUs may be specified by
          the rcu_nocbs= boot parameter.

config RCU_NOCB_CPU_NONE
        bool "No build_forced no-CBs CPUs"
        depends on RCU_NOCB_CPU && !NO_HZ_FULL
        help
          This option does not force any of the CPUs to be no-CBs CPUs.
          Only CPUs designated by the rcu_nocbs= boot parameter will be
          no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
          kthreads whose names begin with "rcuo".  All other CPUs will
          invoke their own RCU callbacks in softirq context.

          Select this option if you want to choose no-CBs CPUs at
          boot time, for example, to allow testing of different no-CBs
          configurations without having to rebuild the kernel each time.

config RCU_NOCB_CPU_ZERO
        bool "CPU 0 is a build_forced no-CBs CPU"
        depends on RCU_NOCB_CPU && !NO_HZ_FULL
        help
          This option forces CPU 0 to be a no-CBs CPU, so that its RCU
          callbacks are invoked by a per-CPU kthread whose name begins
          with "rcuo".  Additional CPUs may be designated as no-CBs
          CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
          All other CPUs will invoke their own RCU callbacks in softirq
          context.

          Select this if CPU 0 needs to be a no-CBs CPU for real-time
          or energy-efficiency reasons, but the real reason it exists
          is to ensure that randconfig testing covers mixed systems.

config RCU_NOCB_CPU_ALL
        bool "All CPUs are build_forced no-CBs CPUs"
        depends on RCU_NOCB_CPU
        help
          This option forces all CPUs to be no-CBs CPUs.  The rcu_nocbs=
          boot parameter will be ignored.  All CPUs' RCU callbacks will
          be executed in the context of per-CPU rcuo kthreads created for
          this purpose.  Assuming that the kthreads whose names start with
          "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
          on the remaining CPUs, but might decrease memory locality during
          RCU-callback invocation, thus potentially degrading throughput.

          Select this if all CPUs need to be no-CBs CPUs for real-time
          or energy-efficiency reasons.

endchoice

endmenu # "RCU Subsystem"

config IKCONFIG
        tristate "Kernel .config support"
        ---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.

config LOG_BUF_SHIFT
        int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
        range 12 21
        default 17
        help
          Select kernel log buffer size as a power of 2.
          Examples:
                     17 => 128 KB
                     16 => 64 KB
                     15 => 32 KB
                     14 => 16 KB
                     13 =>  8 KB
                     12 =>  4 KB

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

config GENERIC_SCHED_CLOCK
        bool

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

# 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

#
# For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
config ARCH_WANTS_PROT_NUMA_PROT_NONE
        bool

config ARCH_USES_NUMA_PROT_NONE
        bool
        default y
        depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
        depends on NUMA_BALANCING

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

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
          it is references to the node the task is running on.

          This system will be inactive on UMA systems.

menuconfig CGROUPS
        boolean "Control Group support"
        depends on EVENTFD
        help
          This option adds support for grouping sets of processes together, for
          use with process control subsystems such as Cpusets, CFS, memory
          controls or device isolation.
          See
                - Documentation/scheduler/sched-design-CFS.txt  (CFS)
                - Documentation/cgroups/ (features for grouping, isolation
                                          and resource control)

          Say N if unsure.

if CGROUPS

config CGROUP_DEBUG
        bool "Example debug cgroup subsystem"
        default n
        help
          This option enables a simple cgroup subsystem that
          exports useful debugging information about the cgroups
          framework.

          Say N if unsure.

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

config CGROUP_DEVICE
        bool "Device controller for cgroups"
        help
          Provides a cgroup implementing whitelists for devices which
          a process in the cgroup can mknod or open.

config CPUSETS
        bool "Cpuset support"
        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.

          Say N if unsure.

config PROC_PID_CPUSET
        bool "Include legacy /proc/<pid>/cpuset file"
        depends on CPUSETS
        default y

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

config RESOURCE_COUNTERS
        bool "Resource counters"
        help
          This option enables controller independent resource accounting
          infrastructure that works with cgroups.

config MEMCG
        bool "Memory Resource Controller for Control Groups"
        depends on RESOURCE_COUNTERS
        select MM_OWNER
        help
          Provides a memory resource controller that manages both anonymous
          memory and page cache. (See Documentation/cgroups/memory.txt)

          Note that setting this option increases fixed memory overhead
          associated with each page of memory in the system. By this,
          8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
          usage tracking struct at boot. Total amount of this is printed out
          at boot.

          Only enable when you're ok with these trade offs and really
          sure you need the memory resource controller. Even when you enable
          this, you can set "cgroup_disable=memory" at your boot option to
          disable memory resource controller and you can avoid overheads.
          (and lose benefits of memory resource controller)

          This config option also selects MM_OWNER config option, which
          could in turn add some fork/exit overhead.

config MEMCG_SWAP
        bool "Memory Resource Controller Swap Extension"
        depends on MEMCG && SWAP
        help
          Add swap management feature to memory resource controller. When you
          enable this, you can limit mem+swap usage per cgroup. In other words,
          when you disable this, memory resource controller has no cares to
          usage of swap...a process can exhaust all of the swap. This extension
          is useful when you want to avoid exhaustion swap but this itself
          adds more overheads and consumes memory for remembering information.
          Especially if you use 32bit system or small memory system, please
          be careful about enabling this. When memory resource controller
          is disabled by boot option, this will be automatically disabled and
          there will be no overhead from this. Even when you set this config=y,
          if boot option "swapaccount=0" is set, swap will not be accounted.
          Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
          size is 4096bytes, 512k per 1Gbytes of swap.
config MEMCG_SWAP_ENABLED
        bool "Memory Resource Controller Swap Extension enabled by default"
        depends on MEMCG_SWAP
        default y
        help
          Memory Resource Controller Swap Extension comes with its price in
          a bigger memory consumption. General purpose distribution kernels
          which want to enable the feature but keep it disabled by default
          and let the user enable it by swapaccount=1 boot command line
          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
          then swapaccount=0 does the trick).
config MEMCG_KMEM
        bool "Memory Resource Controller Kernel Memory accounting"
        depends on MEMCG
        depends on SLUB || SLAB
        help
          The Kernel Memory extension for Memory Resource Controller can limit
          the amount of memory used by kernel objects in the system. Those are
          fundamentally different from the entities handled by the standard
          Memory Controller, which are page-based, and can be swapped. Users of
          the kmem extension can use it to guarantee that no group of processes
          will ever exhaust kernel resources alone.

config CGROUP_HUGETLB
        bool "HugeTLB Resource Controller for Control Groups"
        depends on RESOURCE_COUNTERS && HUGETLB_PAGE
        default n
        help
          Provides a cgroup Resource 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.

config CGROUP_PERF
        bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
        depends on PERF_EVENTS && CGROUPS
        help
          This option extends the per-cpu mode to restrict monitoring to
          threads which belong to the cgroup specified and run on the
          designated cpu.

          Say N if unsure.

menuconfig CGROUP_SCHED
        bool "Group CPU scheduler"
        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

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.

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
          to task groups. If enabled, it will also make it impossible to
          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

config BLK_CGROUP
        bool "Block IO controller"
        depends on BLOCK
        default n
        ---help---
        Generic block IO controller cgroup interface. This is the common
        cgroup interface which should be used by various IO controlling
        policies.

        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.

        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.

        See Documentation/cgroups/blkio-controller.txt for more information.

config DEBUG_BLK_CGROUP
        bool "Enable Block 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.

endif # CGROUPS

config CHECKPOINT_RESTORE
        bool "Checkpoint/restore support" if EXPERT
        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.

menuconfig NAMESPACES
        bool "Namespaces support" if EXPERT
        default !EXPERT
        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.

if NAMESPACES

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

config IPC_NS
        bool "IPC namespace"
        depends on (SYSVIPC || POSIX_MQUEUE)
        default y
        help
          In this namespace tasks work with IPC ids which correspond to
          different IPC objects in different namespaces.

config USER_NS
        bool "User namespace"
        select UIDGID_STRICT_TYPE_CHECKS

        default n
        help
          This allows containers, i.e. vservers, to use user namespaces
          to provide different user info for different servers.

          When user namespaces are enabled in the kernel it is
          recommended that the MEMCG and MEMCG_KMEM options also be
          enabled and that user-space use the memory control groups to
          limit the amount of memory a memory unprivileged users can
          use.

          If unsure, say N.

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

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

endif # NAMESPACES

config UIDGID_STRICT_TYPE_CHECKS
        bool "Require conversions between uid/gids and their internal representation"
        default n
        help
         While the nececessary conversions are being added to all subsystems this option allows
         the code to continue to build for unconverted subsystems.

         Say Y here if you want the strict type checking enabled

config SCHED_AUTOGROUP
        bool "Automatic process group scheduling"
        select EVENTFD
        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.

config MM_OWNER
        bool

config SYSFS_DEPRECATED
        bool "Enable deprecated sysfs features to support old userspace tools"
        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
        bool "Enable deprecated sysfs features by default"
        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)"
        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.

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,
          etc. See <file:Documentation/initrd.txt> for details.

          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.

if BLK_DEV_INITRD

source "usr/Kconfig"

endif

config CC_OPTIMIZE_FOR_SIZE
        bool "Optimize for size"
        help
          Enabling this option will pass "-Os" instead of "-O2" to gcc
          resulting in a smaller kernel.

          If unsure, say N.

config SYSCTL
        bool

config ANON_INODES
        bool

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

menuconfig EXPERT
        bool "Configure standard kernel features (expert users)"
        # Unhide debug options, to make the on-by-default options visible
        select DEBUG_KERNEL
        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.

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

config SYSCTL_SYSCALL
        bool "Sysctl syscall support" if EXPERT
        depends on PROC_SYSCTL
        default n
        select SYSCTL
        ---help---
          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.

          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.

          If unsure say N here.

config KALLSYMS
         bool "Load all symbols for debugging/ksymoops" if EXPERT
         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
           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.

config PRINTK
        default y
        bool "Enable support for printk" if EXPERT
        select IRQ_WORK
        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.

config BUG
        bool "BUG() support" if EXPERT
        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.

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


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

config BASE_FULL
        default y
        bool "Enable full-sized data structures for core" if EXPERT
        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
        bool "Enable futex support" if EXPERT
        default y
        select RT_MUTEXES
        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.

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

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

          If unsure, say Y.

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

          If unsure, say Y.

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

          If unsure, say Y.

config SHMEM
        bool "Use full shmem filesystem" if EXPERT
        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.

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

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.

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

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

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

menu "Kernel Performance Events And Counters"

config PERF_EVENTS
        bool "Kernel performance events and counters"
        default y if PROFILING
        depends on HAVE_PERF_EVENTS
        select ANON_INODES
        select IRQ_WORK
        help
          Enable kernel support for various performance events provided
          by software and hardware.

          Software events are supported either built-in or via the
          use of generic tracepoints.

          Most modern CPUs support performance events via performance
          counter registers. These registers count the number of certain
          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.

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

          Say Y if unsure.

config DEBUG_PERF_USE_VMALLOC
        default n
        bool "Debug: use vmalloc to back perf mmap() buffers"
        depends on PERF_EVENTS && DEBUG_KERNEL
        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.

endmenu

config VM_EVENT_COUNTERS
        default y
        bool "Enable VM event counters for /proc/vmstat" if EXPERT
        help
          VM event counters are needed for event counts to be shown.
          This option allows the disabling of the VM event counters
          on EXPERT systems.  /proc/vmstat will only show page counts
          if VM event counters are disabled.

config SLUB_DEBUG
        default y
        bool "Enable SLUB debugging support" if EXPERT
        depends on SLUB && SYSFS
        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.

config COMPAT_BRK
        bool "Disable heap randomization"
        default y
        help
          Randomizing heap placement makes heap exploits harder, but it
          also breaks ancient binaries (including anything libc5 based).
          This option changes the bootup default to heap randomization
          disabled, and can be overridden at runtime by setting
          /proc/sys/kernel/randomize_va_space to 2.

          On non-ancient distros (post-2000 ones) N is usually a safe choice.

choice
        prompt "Choose SLAB allocator"
        default SLUB
        help
           This option allows to select a slab allocator.

config SLAB
        bool "SLAB"
        help
          The regular slab allocator that is established and known to work
          well in all environments. It organizes cache hot objects in
          per cpu and per node queues.

config SLUB
        bool "SLUB (Unqueued Allocator)"
        help
           SLUB is a slab allocator that minimizes cache line usage
           instead of managing queues of cached objects (SLAB approach).
           Per cpu caching is realized using slabs of objects instead
           of queues of objects. SLUB can use memory efficiently
           and has enhanced diagnostics. SLUB is the default choice for
           a slab allocator.

config SLOB
        depends on EXPERT
        bool "SLOB (Simple Allocator)"
        help
           SLOB replaces the stock allocator with a drastically simpler
           allocator. SLOB is generally more space efficient but
           does not perform as well on large systems.

endchoice

config SLUB_CPU_PARTIAL
        default y
        depends on SLUB && SMP
        bool "SLUB per cpu partial cache"
        help
          Per cpu partial caches accellerate objects allocation and freeing
          that is local to a processor at the price of more indeterminism
          in the latency of the free. On overflow these caches will be cleared
          which requires the taking of locks that may cause latency spikes.
          Typically one would choose no for a realtime system.

config MMAP_ALLOW_UNINITIALIZED
        bool "Allow mmapped anonymous memory to be uninitialized"
        depends on EXPERT && !MMU
        default n
        help
          Normally, and according to the Linux spec, anonymous memory obtained
          from mmap() has it's contents cleared before it is passed to
          userspace.  Enabling this config option allows you to request that
          mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
          providing a huge performance boost.  If this option is not enabled,
          then the flag will be ignored.

          This is taken advantage of by uClibc's malloc(), and also by
          ELF-FDPIC binfmt's brk and stack allocator.

          Because of the obvious security issues, this option should only be
          enabled on embedded devices where you control what is run in
          userspace.  Since that isn't generally a problem on no-MMU systems,
          it is normally safe to say Y here.

          See Documentation/nommu-mmap.txt for more information.

config PROFILING
        bool "Profiling support"
        help
          Say Y here to enable the extended profiling support mechanisms used
          by profilers such as OProfile.

#
# Place an empty function call at each tracepoint site. Can be
# dynamically changed for a probe function.
#
config TRACEPOINTS
        bool

source "arch/Kconfig"

endmenu         # General setup

config HAVE_GENERIC_DMA_COHERENT
        bool
        default n

config SLABINFO
        bool
        depends on PROC_FS
        depends on SLAB || SLUB_DEBUG
        default y

config RT_MUTEXES
        boolean

config BASE_SMALL
        int
        default 0 if BASE_FULL
        default 1 if !BASE_FULL

menuconfig MODULES
        bool "Enable loadable module support"
        option modules
        help
          Kernel modules are small pieces of compiled code which can
          be inserted in the running kernel, rather than being
          permanently built into the kernel.  You use the "modprobe"
          tool to add (and sometimes remove) them.  If you say Y here,
          many parts of the kernel can be built as modules (by
          answering M instead of Y where indicated): this is most
          useful for infrequently used options which are not required
          for booting.  For more information, see the man pages for
          modprobe, lsmod, modinfo, insmod and rmmod.

          If you say Y here, you will need to run "make
          modules_install" to put the modules under /lib/modules/
          where modprobe can find them (you may need to be root to do
          this).

          If unsure, say Y.

if MODULES

config MODULE_FORCE_LOAD
        bool "Forced module loading"
        default n
        help
          Allow loading of modules without version information (ie. modprobe
          --force).  Forced module loading sets the 'F' (forced) taint flag and
          is usually a really bad idea.

config MODULE_UNLOAD
        bool "Module unloading"
        help
          Without this option you will not be able to unload any
          modules (note that some modules may not be unloadable
          anyway), which makes your kernel smaller, faster
          and simpler.  If unsure, say Y.

config MODULE_FORCE_UNLOAD
        bool "Forced module unloading"
        depends on MODULE_UNLOAD
        help
          This option allows you to force a module to unload, even if the
          kernel believes it is unsafe: the kernel will remove the module
          without waiting for anyone to stop using it (using the -f option to
          rmmod).  This is mainly for kernel developers and desperate users.
          If unsure, say N.

config MODVERSIONS
        bool "Module versioning support"
        help
          Usually, you have to use modules compiled with your kernel.
          Saying Y here makes it sometimes possible to use modules
          compiled for different kernels, by adding enough information
          to the modules to (hopefully) spot any changes which would
          make them incompatible with the kernel you are running.  If
          unsure, say N.

config MODULE_SRCVERSION_ALL
        bool "Source checksum for all modules"
        help
          Modules which contain a MODULE_VERSION get an extra "srcversion"
          field inserted into their modinfo section, which contains a
          sum of the source files which made it.  This helps maintainers
          see exactly which source was used to build a module (since
          others sometimes change the module source without updating
          the version).  With this option, such a "srcversion" field
          will be created for all modules.  If unsure, say N.

config MODULE_SIG
        bool "Module signature verification"
        depends on MODULES
        select KEYS
        select CRYPTO
        select ASYMMETRIC_KEY_TYPE
        select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
        select PUBLIC_KEY_ALGO_RSA
        select ASN1
        select OID_REGISTRY
        select X509_CERTIFICATE_PARSER
        help
          Check modules for valid signatures upon load: the signature
          is simply appended to the module. For more information see
          Documentation/module-signing.txt.

          !!!WARNING!!!  If you enable this option, you MUST make sure that the
          module DOES NOT get stripped after being signed.  This includes the
          debuginfo strip done by some packagers (such as rpmbuild) and
          inclusion into an initramfs that wants the module size reduced.

config MODULE_SIG_FORCE
        bool "Require modules to be validly signed"
        depends on MODULE_SIG
        help
          Reject unsigned modules or signed modules for which we don't have a
          key.  Without this, such modules will simply taint the kernel.

config MODULE_SIG_ALL
        bool "Automatically sign all modules"
        default y
        depends on MODULE_SIG
        help
          Sign all modules during make modules_install. Without this option,
          modules must be signed manually, using the scripts/sign-file tool.

comment "Do not forget to sign required modules with scripts/sign-file"
        depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL

choice
        prompt "Which hash algorithm should modules be signed with?"
        depends on MODULE_SIG
        help
          This determines which sort of hashing algorithm will be used during
          signature generation.  This algorithm _must_ be built into the kernel
          directly so that signature verification can take place.  It is not
          possible to load a signed module containing the algorithm to check
          the signature on that module.

config MODULE_SIG_SHA1
        bool "Sign modules with SHA-1"
        select CRYPTO_SHA1

config MODULE_SIG_SHA224
        bool "Sign modules with SHA-224"
        select CRYPTO_SHA256

config MODULE_SIG_SHA256
        bool "Sign modules with SHA-256"
        select CRYPTO_SHA256

config MODULE_SIG_SHA384
        bool "Sign modules with SHA-384"
        select CRYPTO_SHA512

config MODULE_SIG_SHA512
        bool "Sign modules with SHA-512"
        select CRYPTO_SHA512

endchoice

config MODULE_SIG_HASH
        string
        depends on MODULE_SIG
        default "sha1" if MODULE_SIG_SHA1
        default "sha224" if MODULE_SIG_SHA224
        default "sha256" if MODULE_SIG_SHA256
        default "sha384" if MODULE_SIG_SHA384
        default "sha512" if MODULE_SIG_SHA512

endif # MODULES

config INIT_ALL_POSSIBLE
        bool
        help
          Back when each arch used to define their own cpu_online_mask and
          cpu_possible_mask, some of them chose to initialize cpu_possible_mask
          with all 1s, and others with all 0s.  When they were centralised,
          it was better to provide this option than to break all the archs
          and have several arch maintainers pursuing me down dark alleys.

config STOP_MACHINE
        bool
        default y
        depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
        help
          Need stop_machine() primitive.

source "block/Kconfig"

config PREEMPT_NOTIFIERS
        bool

config PADATA
        depends on SMP
        bool

# Can be selected by architectures with broken toolchains
# that get confused by correct const<->read_only section
# mappings
config BROKEN_RODATA
        bool

config ASN1
        tristate
        help
          Build a simple ASN.1 grammar compiler that produces a bytecode output
          that can be interpreted by the ASN.1 stream decoder and used to
          inform it as to what tags are to be expected in a stream and what
          functions to call on what tags.

source "kernel/Kconfig.locks"