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1589 lines
51 KiB
1589 lines
51 KiB
config ARCH |
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string |
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option env="ARCH" |
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config KERNELVERSION |
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string |
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option env="KERNELVERSION" |
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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 "$ARCH_DEFCONFIG" |
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default "arch/$ARCH/defconfig" |
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config CONSTRUCTORS |
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bool |
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depends on !UML |
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config HAVE_IRQ_WORK |
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bool |
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config IRQ_WORK |
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bool |
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depends on HAVE_IRQ_WORK |
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config BUILDTIME_EXTABLE_SORT |
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bool |
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menu "General setup" |
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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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|
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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 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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config CROSS_COMPILE |
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string "Cross-compiler tool prefix" |
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help |
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Same as running 'make CROSS_COMPILE=prefix-' but stored for |
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default make runs in this kernel build directory. You don't |
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need to set this unless you want the configured kernel build |
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directory to select the cross-compiler automatically. |
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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 belong to the current |
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top of tree revision. |
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A string of the format -gxxxxxxxx will be added to the localversion |
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if a git-based tree is found. The string generated by this will be |
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appended after any matching localversion* files, and after the value |
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set in CONFIG_LOCALVERSION. |
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(The actual string used here is the first eight characters produced |
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by running the command: |
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$ git rev-parse --verify HEAD |
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which is done within the script "scripts/setlocalversion".) |
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config HAVE_KERNEL_GZIP |
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bool |
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config HAVE_KERNEL_BZIP2 |
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bool |
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config HAVE_KERNEL_LZMA |
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bool |
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config HAVE_KERNEL_XZ |
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bool |
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config HAVE_KERNEL_LZO |
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bool |
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choice |
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prompt "Kernel compression mode" |
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default KERNEL_GZIP |
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depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO |
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help |
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The linux kernel is a kind of self-extracting executable. |
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Several compression algorithms are available, which differ |
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in efficiency, compression and decompression speed. |
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Compression speed is only relevant when building a kernel. |
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Decompression speed is relevant at each boot. |
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|
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If you have any problems with bzip2 or lzma compressed |
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kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older |
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version of this functionality (bzip2 only), for 2.4, was |
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supplied by Christian Ludwig) |
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High compression options are mostly useful for users, who |
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are low on disk space (embedded systems), but for whom ram |
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size matters less. |
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If in doubt, select 'gzip' |
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config KERNEL_GZIP |
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bool "Gzip" |
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depends on HAVE_KERNEL_GZIP |
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help |
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The old and tried gzip compression. It provides a good balance |
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between compression ratio and decompression speed. |
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config KERNEL_BZIP2 |
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bool "Bzip2" |
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depends on HAVE_KERNEL_BZIP2 |
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help |
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Its compression ratio and speed is intermediate. |
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Decompression speed is slowest among the choices. The kernel |
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size is about 10% smaller with bzip2, in comparison to gzip. |
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Bzip2 uses a large amount of memory. For modern kernels you |
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will need at least 8MB RAM or more for booting. |
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config KERNEL_LZMA |
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bool "LZMA" |
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depends on HAVE_KERNEL_LZMA |
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help |
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This compression algorithm's ratio is best. Decompression speed |
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is between gzip and bzip2. Compression is slowest. |
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The kernel size is about 33% smaller with LZMA in comparison to gzip. |
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config KERNEL_XZ |
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bool "XZ" |
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depends on HAVE_KERNEL_XZ |
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help |
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XZ uses the LZMA2 algorithm and instruction set specific |
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BCJ filters which can improve compression ratio of executable |
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code. The size of the kernel is about 30% smaller with XZ in |
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comparison to gzip. On architectures for which there is a BCJ |
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filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ |
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will create a few percent smaller kernel than plain LZMA. |
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|
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The speed is about the same as with LZMA: The decompression |
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speed of XZ is better than that of bzip2 but worse than gzip |
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and LZO. Compression is slow. |
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config KERNEL_LZO |
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bool "LZO" |
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depends on HAVE_KERNEL_LZO |
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help |
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Its compression ratio is the poorest among the choices. The kernel |
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size is about 10% bigger than gzip; however its speed |
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(both compression and decompression) is the fastest. |
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endchoice |
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config DEFAULT_HOSTNAME |
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string "Default hostname" |
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default "(none)" |
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help |
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This option determines the default system hostname before userspace |
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calls sethostname(2). The kernel traditionally uses "(none)" here, |
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but you may wish to use a different default here to make a minimal |
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system more usable with less configuration. |
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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 SYSVIPC_SYSCTL |
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bool |
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depends on SYSVIPC |
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depends on SYSCTL |
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default y |
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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. |
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|
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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 POSIX_MQUEUE_SYSCTL |
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bool |
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depends on POSIX_MQUEUE |
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depends on SYSCTL |
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default 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.gnu.org/software/acct/>. |
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config FHANDLE |
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bool "open by fhandle syscalls" |
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select EXPORTFS |
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help |
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If you say Y here, a user level program will be able to map |
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file names to handle and then later use the handle for |
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different file system operations. This is useful in implementing |
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userspace file servers, which now track files using handles instead |
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of names. The handle would remain the same even if file names |
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get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) |
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syscalls. |
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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 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 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 || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) |
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default y if SECURITY_SELINUX |
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help |
|
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. |
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config AUDIT_WATCH |
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def_bool y |
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depends on AUDITSYSCALL |
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select FSNOTIFY |
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config AUDIT_TREE |
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def_bool y |
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depends on AUDITSYSCALL |
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select FSNOTIFY |
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config AUDIT_LOGINUID_IMMUTABLE |
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bool "Make audit loginuid immutable" |
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depends on AUDIT |
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help |
|
The config option toggles if a task setting its loginuid requires |
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CAP_SYS_AUDITCONTROL or if that task should require no special permissions |
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but should instead only allow setting its loginuid if it was never |
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previously set. On systems which use systemd or a similar central |
|
process to restart login services this should be set to true. On older |
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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 |
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one to drop potentially dangerous capabilites from the login tasks, |
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but may not be backwards compatible with older init systems. |
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|
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source "kernel/irq/Kconfig" |
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source "kernel/time/Kconfig" |
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menu "RCU Subsystem" |
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choice |
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prompt "RCU Implementation" |
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default TREE_RCU |
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config TREE_RCU |
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bool "Tree-based hierarchical RCU" |
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depends on !PREEMPT && SMP |
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help |
|
This option selects the RCU implementation that is |
|
designed for very large SMP system with hundreds or |
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thousands of CPUs. It also scales down nicely to |
|
smaller systems. |
|
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config TREE_PREEMPT_RCU |
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bool "Preemptible tree-based hierarchical RCU" |
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depends on PREEMPT && SMP |
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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. |
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config TINY_RCU |
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bool "UP-only small-memory-footprint RCU" |
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depends on !PREEMPT && !SMP |
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help |
|
This option selects the RCU implementation that is |
|
designed for UP systems from which real-time response |
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is not required. This option greatly reduces the |
|
memory footprint of RCU. |
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|
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config TINY_PREEMPT_RCU |
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bool "Preemptible UP-only small-memory-footprint RCU" |
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depends on PREEMPT && !SMP |
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help |
|
This option selects the RCU implementation that is designed |
|
for real-time UP systems. This option greatly reduces the |
|
memory footprint of RCU. |
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|
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endchoice |
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config PREEMPT_RCU |
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def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) |
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help |
|
This option enables preemptible-RCU code that is common between |
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the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. |
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|
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config RCU_FANOUT |
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int "Tree-based hierarchical RCU fanout value" |
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range 2 64 if 64BIT |
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range 2 32 if !64BIT |
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depends on TREE_RCU || TREE_PREEMPT_RCU |
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default 64 if 64BIT |
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default 32 if !64BIT |
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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. |
|
|
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config RCU_FANOUT_LEAF |
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int "Tree-based hierarchical RCU leaf-level fanout value" |
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range 2 RCU_FANOUT if 64BIT |
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range 2 RCU_FANOUT if !64BIT |
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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. |
|
|
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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 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. |
|
|
|
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 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, |
|
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 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 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 (EXPERIMENTAL)" |
|
depends on MEMCG && 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_HUGETLB |
|
bool "HugeTLB Resource Controller for Control Groups" |
|
depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL |
|
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 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 |
|
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 (EXPERIMENTAL)" |
|
depends on EXPERIMENTAL |
|
depends on UIDGID_CONVERTED |
|
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. |
|
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_CONVERTED |
|
# True if all of the selected software conmponents are known |
|
# to have uid_t and gid_t converted to kuid_t and kgid_t |
|
# where appropriate and are otherwise safe to use with |
|
# the user namespace. |
|
bool |
|
default y |
|
|
|
# List of kernel pieces that need user namespace work |
|
# Features |
|
depends on IMA = n |
|
depends on EVM = n |
|
depends on AUDIT = n |
|
depends on AUDITSYSCALL = n |
|
depends on TASKSTATS = n |
|
depends on TRACING = n |
|
depends on FS_POSIX_ACL = n |
|
depends on QUOTA = n |
|
depends on QUOTACTL = n |
|
depends on BSD_PROCESS_ACCT = n |
|
|
|
# Networking |
|
depends on NET_9P = n |
|
depends on AF_RXRPC = n |
|
depends on DNS_RESOLVER = n |
|
|
|
# Filesystems |
|
depends on USB_GADGETFS = n |
|
depends on USB_FUNCTIONFS = n |
|
depends on DEVTMPFS = n |
|
depends on XENFS = n |
|
|
|
depends on 9P_FS = n |
|
depends on ADFS_FS = n |
|
depends on AFFS_FS = n |
|
depends on AFS_FS = n |
|
depends on AUTOFS4_FS = n |
|
depends on BEFS_FS = n |
|
depends on BFS_FS = n |
|
depends on BTRFS_FS = n |
|
depends on CEPH_FS = n |
|
depends on CIFS = n |
|
depends on CODA_FS = n |
|
depends on CONFIGFS_FS = n |
|
depends on CRAMFS = n |
|
depends on ECRYPT_FS = n |
|
depends on EFS_FS = n |
|
depends on EXOFS_FS = n |
|
depends on FAT_FS = n |
|
depends on FUSE_FS = n |
|
depends on GFS2_FS = n |
|
depends on HFS_FS = n |
|
depends on HFSPLUS_FS = n |
|
depends on HPFS_FS = n |
|
depends on HUGETLBFS = n |
|
depends on ISO9660_FS = n |
|
depends on JFFS2_FS = n |
|
depends on JFS_FS = n |
|
depends on LOGFS = n |
|
depends on MINIX_FS = n |
|
depends on NCP_FS = n |
|
depends on NFSD = n |
|
depends on NFS_FS = n |
|
depends on NILFS2_FS = n |
|
depends on NTFS_FS = n |
|
depends on OCFS2_FS = n |
|
depends on OMFS_FS = n |
|
depends on QNX4FS_FS = n |
|
depends on QNX6FS_FS = n |
|
depends on REISERFS_FS = n |
|
depends on SQUASHFS = n |
|
depends on SYSV_FS = n |
|
depends on UBIFS_FS = n |
|
depends on UDF_FS = n |
|
depends on UFS_FS = n |
|
depends on VXFS_FS = n |
|
depends on XFS_FS = n |
|
|
|
depends on !UML || HOSTFS = n |
|
|
|
# The rare drivers that won't build |
|
depends on INFINIBAND_QIB = n |
|
depends on BLK_DEV_LOOP = n |
|
depends on ANDROID_BINDER_IPC = n |
|
|
|
# Security modules |
|
depends on SECURITY_TOMOYO = n |
|
depends on SECURITY_APPARMOR = n |
|
|
|
config UIDGID_STRICT_TYPE_CHECKS |
|
bool "Require conversions between uid/gids and their internal representation" |
|
depends on UIDGID_CONVERTED |
|
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 Y. |
|
|
|
config SYSCTL |
|
bool |
|
|
|
config ANON_INODES |
|
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 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 |
|
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 HOTPLUG |
|
bool "Support for hot-pluggable devices" if EXPERT |
|
default y |
|
help |
|
This option is provided for the case where no hotplug or uevent |
|
capabilities is wanted by the kernel. You should only consider |
|
disabling this option for embedded systems that do not use modules, a |
|
dynamic /dev tree, or dynamic device discovery. Just say Y. |
|
|
|
config PRINTK |
|
default y |
|
bool "Enable support for printk" if EXPERT |
|
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 |
|
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 HAVE_PCSPKR_PLATFORM |
|
bool |
|
|
|
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 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 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 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 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" |
|
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 && 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" |
|
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. |
|
|
|
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 |
|
|
|
source "kernel/Kconfig.locks"
|
|
|