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 HAVE_IRQ_WORK

bool

config IRQ_WORK

bool

depends on HAVE_IRQ_WORK

menu "General setup"

config EXPERIMENTAL

bool "Prompt for development and/or incomplete code/drivers"

---help---

Some of the various things that Linux supports (such as network

drivers, file systems, network protocols, etc.) can be in a state

of development where the functionality, stability, or the level of

testing is not yet high enough for general use. This is usually

known as the "alpha-test" phase among developers. If a feature is

currently in alpha-test, then the developers usually discourage

uninformed widespread use of this feature by the general public to

avoid "Why doesn't this work?" type mail messages. However, active

testing and use of these systems is welcomed. Just be aware that it

may not meet the normal level of reliability or it may fail to work

in some special cases. Detailed bug reports from people familiar

with the kernel internals are usually welcomed by the developers

(before submitting bug reports, please read the documents

<file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,

<file:Documentation/BUG-HUNTING>, and

<file:Documentation/oops-tracing.txt> in the kernel source).

This option will also make obsoleted drivers available. These are

drivers that have been replaced by something else, and/or are

scheduled to be removed in a future kernel release.

Unless you intend to help test and develop a feature or driver that

falls into this category, or you have a situation that requires

using these features, you should probably say N here, which will

cause the configurator to present you with fewer choices. If

you say Y here, you will be offered the choice of using features or

drivers that are currently considered to be in the alpha-test phase.

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 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

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

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 three. 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

The most recent compression algorithm.

Its ratio is best, decompression speed is between the other

two. 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 4. The kernel

size is about 10% bigger than gzip; however its speed

(both compression and decompression) is the fastest.

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 && EXPERIMENTAL

---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 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 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 TASKSTATS

bool "Export task/process statistics through netlink (EXPERIMENTAL)"

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 (EXPERIMENTAL)"

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 (EXPERIMENTAL)"

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 (EXPERIMENTAL)"

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.

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 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)

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"

menu "RCU Subsystem"

choice

prompt "RCU Implementation"

default TREE_RCU

config TREE_RCU

bool "Tree-based hierarchical RCU"

depends on !PREEMPT && SMP

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 && SMP

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.

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.

config TINY_PREEMPT_RCU

bool "Preemptible UP-only small-memory-footprint RCU"

depends on PREEMPT && !SMP

help

This option selects the RCU implementation that is designed

for real-time UP systems. This option greatly reduces the

memory footprint of RCU.

endchoice

config PREEMPT_RCU

def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )

help

This option enables preemptible-RCU code that is common between

the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.

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_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 && SMP

default n

help

This option causes RCU to attempt to accelerate grace periods

in order to allow CPUs to enter dynticks-idle state more

quickly. On the other hand, this option increases the overhead

of the dynticks-idle checking, particularly on systems with

large numbers of CPUs.

Say Y if energy efficiency is critically important, particularly

if you have relatively few CPUs.

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 preempted

RCU readers are to be boosted. If you are working with CPU-bound

real-time applications, you should specify a priority higher then

the highest-priority CPU-bound application.

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.

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

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 CGROUP_MEM_RES_CTLR

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,

20(40)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 CGROUP_MEM_RES_CTLR_SWAP

bool "Memory Resource Controller Swap Extension"

depends on CGROUP_MEM_RES_CTLR && 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 CGROUP_MEM_RES_CTLR_SWAP_ENABLED

bool "Memory Resource Controller Swap Extension enabled by default"

depends on CGROUP_MEM_RES_CTLR_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 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 CGROUP_MEM_RES_CTLR_KMEM

bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"

depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL

default n

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_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 EXPERIMENTAL

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 EXPERIMENTAL

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

tristate "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 (EXPERIMENTAL)"

depends on EXPERIMENTAL

default y

help

This allows containers, i.e. vservers, to use user namespaces

to provide different user info for different servers.

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 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 Y.

config SYSCTL

bool

config ANON_INODES

bool

config PANIC_TIMEOUT

int "Default panic timeout"

default 0

help

Set default panic timeout.

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 ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)

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