2aea4fb616
The VM event counters, enabled by CONFIG_VM_EVENT_COUNTERS, which provides VM event counters in /proc/vmstat, has become more essential to non-EMBEDDED kernel configurations than they were in the past. Comments in the code and the Kconfig configuration explanation were stale, downplaying their role excessively. Refresh those comments to correctly reflect the current role of VM event counters. Signed-off-by: Paul Jackson <pj@sgi.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
574 lines
20 KiB
Text
574 lines
20 KiB
Text
config DEFCONFIG_LIST
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string
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depends on !UML
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option defconfig_list
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default "/lib/modules/$UNAME_RELEASE/.config"
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default "/etc/kernel-config"
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default "/boot/config-$UNAME_RELEASE"
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default "arch/$ARCH/defconfig"
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menu "Code maturity level options"
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config EXPERIMENTAL
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bool "Prompt for development and/or incomplete code/drivers"
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---help---
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Some of the various things that Linux supports (such as network
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drivers, file systems, network protocols, etc.) can be in a state
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of development where the functionality, stability, or the level of
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testing is not yet high enough for general use. This is usually
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known as the "alpha-test" phase among developers. If a feature is
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currently in alpha-test, then the developers usually discourage
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uninformed widespread use of this feature by the general public to
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avoid "Why doesn't this work?" type mail messages. However, active
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testing and use of these systems is welcomed. Just be aware that it
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may not meet the normal level of reliability or it may fail to work
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in some special cases. Detailed bug reports from people familiar
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with the kernel internals are usually welcomed by the developers
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(before submitting bug reports, please read the documents
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<file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
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<file:Documentation/BUG-HUNTING>, and
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<file:Documentation/oops-tracing.txt> in the kernel source).
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This option will also make obsoleted drivers available. These are
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drivers that have been replaced by something else, and/or are
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scheduled to be removed in a future kernel release.
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Unless you intend to help test and develop a feature or driver that
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falls into this category, or you have a situation that requires
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using these features, you should probably say N here, which will
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cause the configurator to present you with fewer choices. If
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you say Y here, you will be offered the choice of using features or
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drivers that are currently considered to be in the alpha-test phase.
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config BROKEN
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bool
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config BROKEN_ON_SMP
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bool
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depends on BROKEN || !SMP
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default y
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config LOCK_KERNEL
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bool
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depends on SMP || PREEMPT
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default y
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config INIT_ENV_ARG_LIMIT
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int
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default 32 if !UML
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default 128 if UML
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help
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Maximum of each of the number of arguments and environment
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variables passed to init from the kernel command line.
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endmenu
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menu "General setup"
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config LOCALVERSION
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string "Local version - append to kernel release"
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help
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Append an extra string to the end of your kernel version.
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This will show up when you type uname, for example.
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The string you set here will be appended after the contents of
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any files with a filename matching localversion* in your
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object and source tree, in that order. Your total string can
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be a maximum of 64 characters.
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config LOCALVERSION_AUTO
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bool "Automatically append version information to the version string"
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default y
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help
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This will try to automatically determine if the current tree is a
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release tree by looking for git tags that
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belong to the current top of tree revision.
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A string of the format -gxxxxxxxx will be added to the localversion
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if a git based tree is found. The string generated by this will be
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appended after any matching localversion* files, and after the value
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set in CONFIG_LOCALVERSION
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Note: This requires Perl, and a git repository, but not necessarily
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the git or cogito tools to be installed.
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config SWAP
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bool "Support for paging of anonymous memory (swap)"
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depends on MMU && BLOCK
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default y
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help
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This option allows you to choose whether you want to have support
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for so called swap devices or swap files in your kernel that are
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used to provide more virtual memory than the actual RAM present
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in your computer. If unsure say Y.
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config SYSVIPC
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bool "System V IPC"
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---help---
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Inter Process Communication is a suite of library functions and
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system calls which let processes (running programs) synchronize and
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exchange information. It is generally considered to be a good thing,
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and some programs won't run unless you say Y here. In particular, if
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you want to run the DOS emulator dosemu under Linux (read the
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DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
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you'll need to say Y here.
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You can find documentation about IPC with "info ipc" and also in
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section 6.4 of the Linux Programmer's Guide, available from
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<http://www.tldp.org/guides.html>.
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config IPC_NS
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bool "IPC Namespaces"
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depends on SYSVIPC
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default n
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help
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Support ipc namespaces. This allows containers, i.e. virtual
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environments, to use ipc namespaces to provide different ipc
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objects for different servers. If unsure, say N.
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config POSIX_MQUEUE
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bool "POSIX Message Queues"
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depends on NET && EXPERIMENTAL
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---help---
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POSIX variant of message queues is a part of IPC. In POSIX message
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queues every message has a priority which decides about succession
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of receiving it by a process. If you want to compile and run
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programs written e.g. for Solaris with use of its POSIX message
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queues (functions mq_*) say Y here. To use this feature you will
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also need mqueue library, available from
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<http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
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POSIX message queues are visible as a filesystem called 'mqueue'
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and can be mounted somewhere if you want to do filesystem
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operations on message queues.
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If unsure, say Y.
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config BSD_PROCESS_ACCT
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bool "BSD Process Accounting"
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help
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If you say Y here, a user level program will be able to instruct the
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kernel (via a special system call) to write process accounting
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information to a file: whenever a process exits, information about
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that process will be appended to the file by the kernel. The
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information includes things such as creation time, owning user,
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command name, memory usage, controlling terminal etc. (the complete
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list is in the struct acct in <file:include/linux/acct.h>). It is
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up to the user level program to do useful things with this
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information. This is generally a good idea, so say Y.
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config BSD_PROCESS_ACCT_V3
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bool "BSD Process Accounting version 3 file format"
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depends on BSD_PROCESS_ACCT
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default n
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help
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If you say Y here, the process accounting information is written
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in a new file format that also logs the process IDs of each
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process and it's parent. Note that this file format is incompatible
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with previous v0/v1/v2 file formats, so you will need updated tools
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for processing it. A preliminary version of these tools is available
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at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
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config TASKSTATS
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bool "Export task/process statistics through netlink (EXPERIMENTAL)"
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depends on NET
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default n
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help
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Export selected statistics for tasks/processes through the
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generic netlink interface. Unlike BSD process accounting, the
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statistics are available during the lifetime of tasks/processes as
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responses to commands. Like BSD accounting, they are sent to user
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space on task exit.
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Say N if unsure.
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config TASK_DELAY_ACCT
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bool "Enable per-task delay accounting (EXPERIMENTAL)"
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depends on TASKSTATS
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help
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Collect information on time spent by a task waiting for system
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resources like cpu, synchronous block I/O completion and swapping
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in pages. Such statistics can help in setting a task's priorities
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relative to other tasks for cpu, io, rss limits etc.
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Say N if unsure.
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config UTS_NS
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bool "UTS Namespaces"
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default n
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help
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Support uts namespaces. This allows containers, i.e.
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vservers, to use uts namespaces to provide different
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uts info for different servers. If unsure, say N.
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config AUDIT
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bool "Auditing support"
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depends on NET
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help
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Enable auditing infrastructure that can be used with another
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kernel subsystem, such as SELinux (which requires this for
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logging of avc messages output). Does not do system-call
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auditing without CONFIG_AUDITSYSCALL.
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config AUDITSYSCALL
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bool "Enable system-call auditing support"
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depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
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default y if SECURITY_SELINUX
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help
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Enable low-overhead system-call auditing infrastructure that
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can be used independently or with another kernel subsystem,
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such as SELinux. To use audit's filesystem watch feature, please
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ensure that INOTIFY is configured.
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config IKCONFIG
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tristate "Kernel .config support"
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---help---
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This option enables the complete Linux kernel ".config" file
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contents to be saved in the kernel. It provides documentation
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of which kernel options are used in a running kernel or in an
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on-disk kernel. This information can be extracted from the kernel
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image file with the script scripts/extract-ikconfig and used as
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input to rebuild the current kernel or to build another kernel.
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It can also be extracted from a running kernel by reading
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/proc/config.gz if enabled (below).
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config IKCONFIG_PROC
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bool "Enable access to .config through /proc/config.gz"
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depends on IKCONFIG && PROC_FS
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---help---
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This option enables access to the kernel configuration file
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through /proc/config.gz.
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config CPUSETS
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bool "Cpuset support"
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depends on SMP
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help
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This option will let you create and manage CPUSETs which
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allow dynamically partitioning a system into sets of CPUs and
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Memory Nodes and assigning tasks to run only within those sets.
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This is primarily useful on large SMP or NUMA systems.
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Say N if unsure.
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config SYSFS_DEPRECATED
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bool "Create deprecated sysfs files"
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default y
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help
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This option creates deprecated symlinks such as the
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"device"-link, the <subsystem>:<name>-link, and the
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"bus"-link. It may also add deprecated key in the
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uevent environment.
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None of these features or values should be used today, as
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they export driver core implementation details to userspace
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or export properties which can't be kept stable across kernel
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releases.
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If enabled, this option will also move any device structures
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that belong to a class, back into the /sys/class heirachy, in
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order to support older versions of udev.
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If you are using a distro that was released in 2006 or later,
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it should be safe to say N here.
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config RELAY
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bool "Kernel->user space relay support (formerly relayfs)"
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help
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This option enables support for relay interface support in
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certain file systems (such as debugfs).
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It is designed to provide an efficient mechanism for tools and
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facilities to relay large amounts of data from kernel space to
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user space.
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If unsure, say N.
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source "usr/Kconfig"
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config CC_OPTIMIZE_FOR_SIZE
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bool "Optimize for size (Look out for broken compilers!)"
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default y
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depends on ARM || H8300 || EXPERIMENTAL
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help
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Enabling this option will pass "-Os" instead of "-O2" to gcc
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resulting in a smaller kernel.
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WARNING: some versions of gcc may generate incorrect code with this
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option. If problems are observed, a gcc upgrade may be needed.
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If unsure, say N.
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config TASK_XACCT
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bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
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depends on TASKSTATS
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help
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Collect extended task accounting data and send the data
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to userland for processing over the taskstats interface.
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Say N if unsure.
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config TASK_IO_ACCOUNTING
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bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
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depends on TASK_XACCT
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help
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Collect information on the number of bytes of storage I/O which this
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task has caused.
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Say N if unsure.
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config SYSCTL
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bool
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menuconfig EMBEDDED
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bool "Configure standard kernel features (for small systems)"
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help
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This option allows certain base kernel options and settings
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to be disabled or tweaked. This is for specialized
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environments which can tolerate a "non-standard" kernel.
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Only use this if you really know what you are doing.
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config UID16
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bool "Enable 16-bit UID system calls" if EMBEDDED
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depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
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default y
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help
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This enables the legacy 16-bit UID syscall wrappers.
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config SYSCTL_SYSCALL
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bool "Sysctl syscall support" if EMBEDDED
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default y
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select SYSCTL
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---help---
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sys_sysctl uses binary paths that have been found challenging
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to properly maintain and use. The interface in /proc/sys
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using paths with ascii names is now the primary path to this
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information.
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Almost nothing using the binary sysctl interface so if you are
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trying to save some space it is probably safe to disable this,
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making your kernel marginally smaller.
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If unsure say Y here.
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config KALLSYMS
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bool "Load all symbols for debugging/ksymoops" if EMBEDDED
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default y
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help
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Say Y here to let the kernel print out symbolic crash information and
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symbolic stack backtraces. This increases the size of the kernel
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somewhat, as all symbols have to be loaded into the kernel image.
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config KALLSYMS_ALL
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bool "Include all symbols in kallsyms"
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depends on DEBUG_KERNEL && KALLSYMS
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help
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Normally kallsyms only contains the symbols of functions, for nicer
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OOPS messages. Some debuggers can use kallsyms for other
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symbols too: say Y here to include all symbols, if you need them
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and you don't care about adding 300k to the size of your kernel.
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Say N.
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config KALLSYMS_EXTRA_PASS
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bool "Do an extra kallsyms pass"
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depends on KALLSYMS
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help
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If kallsyms is not working correctly, the build will fail with
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inconsistent kallsyms data. If that occurs, log a bug report and
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turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
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Always say N here unless you find a bug in kallsyms, which must be
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reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
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you wait for kallsyms to be fixed.
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config HOTPLUG
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bool "Support for hot-pluggable devices" if EMBEDDED
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default y
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help
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This option is provided for the case where no hotplug or uevent
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capabilities is wanted by the kernel. You should only consider
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disabling this option for embedded systems that do not use modules, a
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dynamic /dev tree, or dynamic device discovery. Just say Y.
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config PRINTK
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default y
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bool "Enable support for printk" if EMBEDDED
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help
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This option enables normal printk support. Removing it
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eliminates most of the message strings from the kernel image
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and makes the kernel more or less silent. As this makes it
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very difficult to diagnose system problems, saying N here is
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strongly discouraged.
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config BUG
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bool "BUG() support" if EMBEDDED
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default y
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help
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Disabling this option eliminates support for BUG and WARN, reducing
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the size of your kernel image and potentially quietly ignoring
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numerous fatal conditions. You should only consider disabling this
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option for embedded systems with no facilities for reporting errors.
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Just say Y.
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config ELF_CORE
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default y
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bool "Enable ELF core dumps" if EMBEDDED
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help
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Enable support for generating core dumps. Disabling saves about 4k.
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config BASE_FULL
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default y
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bool "Enable full-sized data structures for core" if EMBEDDED
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help
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Disabling this option reduces the size of miscellaneous core
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kernel data structures. This saves memory on small machines,
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but may reduce performance.
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config FUTEX
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bool "Enable futex support" if EMBEDDED
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default y
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select RT_MUTEXES
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help
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Disabling this option will cause the kernel to be built without
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support for "fast userspace mutexes". The resulting kernel may not
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run glibc-based applications correctly.
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config EPOLL
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bool "Enable eventpoll support" if EMBEDDED
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default y
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help
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Disabling this option will cause the kernel to be built without
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support for epoll family of system calls.
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config SHMEM
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bool "Use full shmem filesystem" if EMBEDDED
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default y
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depends on MMU
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help
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The shmem is an internal filesystem used to manage shared memory.
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It is backed by swap and manages resource limits. It is also exported
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to userspace as tmpfs if TMPFS is enabled. Disabling this
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option replaces shmem and tmpfs with the much simpler ramfs code,
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which may be appropriate on small systems without swap.
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config SLAB
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default y
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bool "Use full SLAB allocator" if EMBEDDED
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help
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Disabling this replaces the advanced SLAB allocator and
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kmalloc support with the drastically simpler SLOB allocator.
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SLOB is more space efficient but does not scale well and is
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more susceptible to fragmentation.
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config VM_EVENT_COUNTERS
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default y
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bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
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help
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VM event counters are needed for event counts to be shown.
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This option allows the disabling of the VM event counters
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on EMBEDDED systems. /proc/vmstat will only show page counts
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if VM event counters are disabled.
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endmenu # General setup
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config RT_MUTEXES
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boolean
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select PLIST
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config TINY_SHMEM
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default !SHMEM
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bool
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config BASE_SMALL
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int
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default 0 if BASE_FULL
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default 1 if !BASE_FULL
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config SLOB
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default !SLAB
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bool
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menu "Loadable module support"
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config MODULES
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bool "Enable loadable module support"
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help
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Kernel modules are small pieces of compiled code which can
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be inserted in the running kernel, rather than being
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permanently built into the kernel. You use the "modprobe"
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tool to add (and sometimes remove) them. If you say Y here,
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many parts of the kernel can be built as modules (by
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answering M instead of Y where indicated): this is most
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useful for infrequently used options which are not required
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for booting. For more information, see the man pages for
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modprobe, lsmod, modinfo, insmod and rmmod.
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If you say Y here, you will need to run "make
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modules_install" to put the modules under /lib/modules/
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where modprobe can find them (you may need to be root to do
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this).
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If unsure, say Y.
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config MODULE_UNLOAD
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bool "Module unloading"
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depends on MODULES
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help
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|
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 slightly smaller and
|
|
simpler. If unsure, say Y.
|
|
|
|
config MODULE_FORCE_UNLOAD
|
|
bool "Forced module unloading"
|
|
depends on MODULE_UNLOAD && EXPERIMENTAL
|
|
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"
|
|
depends on MODULES
|
|
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"
|
|
depends on 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 KMOD
|
|
bool "Automatic kernel module loading"
|
|
depends on MODULES
|
|
help
|
|
Normally when you have selected some parts of the kernel to
|
|
be created as kernel modules, you must load them (using the
|
|
"modprobe" command) before you can use them. If you say Y
|
|
here, some parts of the kernel will be able to load modules
|
|
automatically: when a part of the kernel needs a module, it
|
|
runs modprobe with the appropriate arguments, thereby
|
|
loading the module if it is available. If unsure, say Y.
|
|
|
|
config STOP_MACHINE
|
|
bool
|
|
default y
|
|
depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
|
|
help
|
|
Need stop_machine() primitive.
|
|
endmenu
|
|
|
|
menu "Block layer"
|
|
source "block/Kconfig"
|
|
endmenu
|