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init/Kconfig
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config ARCH string option env="ARCH" config KERNELVERSION string option env="KERNELVERSION" |
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config DEFCONFIG_LIST string |
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depends on !UML |
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option defconfig_list default "/lib/modules/$UNAME_RELEASE/.config" default "/etc/kernel-config" default "/boot/config-$UNAME_RELEASE" |
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default "$ARCH_DEFCONFIG" |
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default "arch/$ARCH/defconfig" |
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config CONSTRUCTORS bool depends on !UML |
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config IRQ_WORK bool |
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config BUILDTIME_EXTABLE_SORT bool |
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config THREAD_INFO_IN_TASK bool help Select this to move thread_info off the stack into task_struct. To make this work, an arch will need to remove all thread_info fields except flags and fix any runtime bugs. |
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One subtle change that will be needed is to use try_get_task_stack() and put_task_stack() in save_thread_stack_tsk() and get_wchan(). |
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menu "General setup" |
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config BROKEN bool |
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config BROKEN_ON_SMP bool depends on BROKEN || !SMP default y |
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config INIT_ENV_ARG_LIMIT int |
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default 32 if !UML default 128 if UML |
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help |
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Maximum of each of the number of arguments and environment variables passed to init from the kernel command line. |
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config CROSS_COMPILE string "Cross-compiler tool prefix" help Same as running 'make CROSS_COMPILE=prefix-' but stored for default make runs in this kernel build directory. You don't need to set this unless you want the configured kernel build directory to select the cross-compiler automatically. |
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config COMPILE_TEST bool "Compile also drivers which will not load" |
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depends on !UML |
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default n help Some drivers can be compiled on a different platform than they are intended to be run on. Despite they cannot be loaded there (or even when they load they cannot be used due to missing HW support), developers still, opposing to distributors, might want to build such drivers to compile-test them. If you are a developer and want to build everything available, say Y here. If you are a user/distributor, say N here to exclude useless drivers to be distributed. |
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config LOCALVERSION string "Local version - append to kernel release" help Append an extra string to the end of your kernel version. This will show up when you type uname, for example. The string you set here will be appended after the contents of any files with a filename matching localversion* in your object and source tree, in that order. Your total string can be a maximum of 64 characters. |
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config LOCALVERSION_AUTO bool "Automatically append version information to the version string" default y |
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depends on !COMPILE_TEST |
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help This will try to automatically determine if the current tree is a |
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release tree by looking for git tags that belong to the current top of tree revision. |
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A string of the format -gxxxxxxxx will be added to the localversion |
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if a git-based tree is found. The string generated by this will be |
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appended after any matching localversion* files, and after the value |
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set in CONFIG_LOCALVERSION. |
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(The actual string used here is the first eight characters produced by running the command: $ git rev-parse --verify HEAD which is done within the script "scripts/setlocalversion".) |
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config HAVE_KERNEL_GZIP bool config HAVE_KERNEL_BZIP2 bool config HAVE_KERNEL_LZMA bool |
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config HAVE_KERNEL_XZ bool |
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config HAVE_KERNEL_LZO bool |
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config HAVE_KERNEL_LZ4 bool |
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choice |
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prompt "Kernel compression mode" default KERNEL_GZIP |
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depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 |
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help |
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The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ in efficiency, compression and decompression speed. Compression speed is only relevant when building a kernel. Decompression speed is relevant at each boot. If you have any problems with bzip2 or lzma compressed kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older version of this functionality (bzip2 only), for 2.4, was supplied by Christian Ludwig) High compression options are mostly useful for users, who are low on disk space (embedded systems), but for whom ram size matters less. If in doubt, select 'gzip' config KERNEL_GZIP |
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bool "Gzip" depends on HAVE_KERNEL_GZIP help |
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The old and tried gzip compression. It provides a good balance between compression ratio and decompression speed. |
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config KERNEL_BZIP2 bool "Bzip2" |
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depends on HAVE_KERNEL_BZIP2 |
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help Its compression ratio and speed is intermediate. |
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Decompression speed is slowest among the choices. The kernel |
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size is about 10% smaller with bzip2, in comparison to gzip. Bzip2 uses a large amount of memory. For modern kernels you will need at least 8MB RAM or more for booting. |
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config KERNEL_LZMA |
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bool "LZMA" depends on HAVE_KERNEL_LZMA help |
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This compression algorithm's ratio is best. Decompression speed is between gzip and bzip2. Compression is slowest. The kernel size is about 33% smaller with LZMA in comparison to gzip. |
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config KERNEL_XZ bool "XZ" depends on HAVE_KERNEL_XZ help XZ uses the LZMA2 algorithm and instruction set specific BCJ filters which can improve compression ratio of executable code. The size of the kernel is about 30% smaller with XZ in comparison to gzip. On architectures for which there is a BCJ filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ will create a few percent smaller kernel than plain LZMA. The speed is about the same as with LZMA: The decompression speed of XZ is better than that of bzip2 but worse than gzip and LZO. Compression is slow. |
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config KERNEL_LZO bool "LZO" depends on HAVE_KERNEL_LZO help |
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Its compression ratio is the poorest among the choices. The kernel |
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size is about 10% bigger than gzip; however its speed |
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(both compression and decompression) is the fastest. |
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config KERNEL_LZ4 bool "LZ4" depends on HAVE_KERNEL_LZ4 help LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. A preliminary version of LZ4 de/compression tool is available at <https://code.google.com/p/lz4/>. Its compression ratio is worse than LZO. The size of the kernel is about 8% bigger than LZO. But the decompression speed is faster than LZO. |
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endchoice |
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config DEFAULT_HOSTNAME string "Default hostname" default "(none)" help This option determines the default system hostname before userspace calls sethostname(2). The kernel traditionally uses "(none)" here, but you may wish to use a different default here to make a minimal system more usable with less configuration. |
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config SWAP bool "Support for paging of anonymous memory (swap)" |
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depends on MMU && BLOCK |
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default y help This option allows you to choose whether you want to have support |
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for so called swap devices or swap files in your kernel that are |
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used to provide more virtual memory than the actual RAM present in your computer. If unsure say Y. config SYSVIPC bool "System V IPC" |
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---help--- Inter Process Communication is a suite of library functions and system calls which let processes (running programs) synchronize and exchange information. It is generally considered to be a good thing, and some programs won't run unless you say Y here. In particular, if you want to run the DOS emulator dosemu under Linux (read the DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), you'll need to say Y here. You can find documentation about IPC with "info ipc" and also in section 6.4 of the Linux Programmer's Guide, available from <http://www.tldp.org/guides.html>. |
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config SYSVIPC_SYSCTL bool depends on SYSVIPC depends on SYSCTL default y |
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config POSIX_MQUEUE bool "POSIX Message Queues" |
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depends on NET |
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---help--- POSIX variant of message queues is a part of IPC. In POSIX message queues every message has a priority which decides about succession of receiving it by a process. If you want to compile and run programs written e.g. for Solaris with use of its POSIX message |
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queues (functions mq_*) say Y here. |
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POSIX message queues are visible as a filesystem called 'mqueue' and can be mounted somewhere if you want to do filesystem operations on message queues. If unsure, say Y. |
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config POSIX_MQUEUE_SYSCTL bool depends on POSIX_MQUEUE depends on SYSCTL default y |
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config CROSS_MEMORY_ATTACH bool "Enable process_vm_readv/writev syscalls" depends on MMU default y help Enabling this option adds the system calls process_vm_readv and process_vm_writev which allow a process with the correct privileges |
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to directly read from or write to another process' address space. |
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See the man page for more details. |
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config FHANDLE |
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bool "open by fhandle syscalls" if EXPERT |
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select EXPORTFS |
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default y |
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help If you say Y here, a user level program will be able to map file names to handle and then later use the handle for different file system operations. This is useful in implementing userspace file servers, which now track files using handles instead of names. The handle would remain the same even if file names get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) syscalls. |
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config USELIB bool "uselib syscall" |
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def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION |
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help This option enables the uselib syscall, a system call used in the dynamic linker from libc5 and earlier. glibc does not use this system call. If you intend to run programs built on libc5 or earlier, you may need to enable this syscall. Current systems running glibc can safely disable this. |
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config AUDIT bool "Auditing support" depends on NET help Enable auditing infrastructure that can be used with another kernel subsystem, such as SELinux (which requires this for |
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logging of avc messages output). System call auditing is included on architectures which support it. |
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config HAVE_ARCH_AUDITSYSCALL bool |
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config AUDITSYSCALL |
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def_bool y |
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depends on AUDIT && HAVE_ARCH_AUDITSYSCALL |
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config AUDIT_WATCH def_bool y depends on AUDITSYSCALL select FSNOTIFY config AUDIT_TREE def_bool y depends on AUDITSYSCALL select FSNOTIFY |
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source "kernel/irq/Kconfig" source "kernel/time/Kconfig" menu "CPU/Task time and stats accounting" |
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config VIRT_CPU_ACCOUNTING bool |
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choice prompt "Cputime accounting" default TICK_CPU_ACCOUNTING if !PPC64 |
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default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
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# Kind of a stub config for the pure tick based cputime accounting config TICK_CPU_ACCOUNTING bool "Simple tick based cputime accounting" |
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depends on !S390 && !NO_HZ_FULL |
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help This is the basic tick based cputime accounting that maintains statistics about user, system and idle time spent on per jiffies granularity. If unsure, say Y. |
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config VIRT_CPU_ACCOUNTING_NATIVE |
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bool "Deterministic task and CPU time accounting" |
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depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
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select VIRT_CPU_ACCOUNTING |
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help Select this option to enable more accurate task and CPU time accounting. This is done by reading a CPU counter on each kernel entry and exit and on transitions within the kernel between system, softirq and hardirq state, so there is a small performance impact. In the case of s390 or IBM POWER > 5, this also enables accounting of stolen time on logically-partitioned systems. |
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config VIRT_CPU_ACCOUNTING_GEN bool "Full dynticks CPU time accounting" |
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depends on HAVE_CONTEXT_TRACKING |
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depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
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select VIRT_CPU_ACCOUNTING select CONTEXT_TRACKING help Select this option to enable task and CPU time accounting on full dynticks systems. This accounting is implemented by watching every kernel-user boundaries using the context tracking subsystem. The accounting is thus performed at the expense of some significant overhead. For now this is only useful if you are working on the full dynticks subsystem development. If unsure, say N. |
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endchoice |
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config IRQ_TIME_ACCOUNTING bool "Fine granularity task level IRQ time accounting" |
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depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE |
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help Select this option to enable fine granularity task irq time accounting. This is done by reading a timestamp on each transitions between softirq and hardirq state, so there can be a small performance impact. If in doubt, say N here. |
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config BSD_PROCESS_ACCT bool "BSD Process Accounting" |
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depends on MULTIUSER |
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help If you say Y here, a user level program will be able to instruct the kernel (via a special system call) to write process accounting information to a file: whenever a process exits, information about that process will be appended to the file by the kernel. The information includes things such as creation time, owning user, command name, memory usage, controlling terminal etc. (the complete list is in the struct acct in <file:include/linux/acct.h>). It is up to the user level program to do useful things with this information. This is generally a good idea, so say Y. config BSD_PROCESS_ACCT_V3 bool "BSD Process Accounting version 3 file format" depends on BSD_PROCESS_ACCT default n help If you say Y here, the process accounting information is written in a new file format that also logs the process IDs of each process and it's parent. Note that this file format is incompatible with previous v0/v1/v2 file formats, so you will need updated tools for processing it. A preliminary version of these tools is available |
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at <http://www.gnu.org/software/acct/>. |
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config TASKSTATS |
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bool "Export task/process statistics through netlink" |
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depends on NET |
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depends on MULTIUSER |
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default n help Export selected statistics for tasks/processes through the generic netlink interface. Unlike BSD process accounting, the statistics are available during the lifetime of tasks/processes as responses to commands. Like BSD accounting, they are sent to user space on task exit. Say N if unsure. |
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config TASK_DELAY_ACCT |
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bool "Enable per-task delay accounting" |
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depends on TASKSTATS |
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select SCHED_INFO |
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help Collect information on time spent by a task waiting for system resources like cpu, synchronous block I/O completion and swapping in pages. Such statistics can help in setting a task's priorities relative to other tasks for cpu, io, rss limits etc. Say N if unsure. |
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config TASK_XACCT |
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bool "Enable extended accounting over taskstats" |
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depends on TASKSTATS help Collect extended task accounting data and send the data to userland for processing over the taskstats interface. Say N if unsure. config TASK_IO_ACCOUNTING |
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bool "Enable per-task storage I/O accounting" |
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depends on TASK_XACCT help Collect information on the number of bytes of storage I/O which this task has caused. Say N if unsure. |
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endmenu # "CPU/Task time and stats accounting" |
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menu "RCU Subsystem" |
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config TREE_RCU |
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bool default y if !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 PREEMPT_RCU |
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bool default y if PREEMPT |
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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 |
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is also required. It also scales down nicely to smaller systems. |
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Select this option if you are unsure. |
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config TINY_RCU |
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bool default y if !PREEMPT && !SMP |
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help This option selects the RCU implementation that is designed for UP systems from which real-time response is not required. This option greatly reduces the memory footprint of RCU. |
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config RCU_EXPERT bool "Make expert-level adjustments to RCU configuration" default n help This option needs to be enabled if you wish to make expert-level adjustments to RCU configuration. By default, no such adjustments can be made, which has the often-beneficial side-effect of preventing "make oldconfig" from asking you all sorts of detailed questions about how you would like numerous obscure RCU options to be set up. Say Y if you need to make expert-level adjustments to RCU. Say N if you are unsure. |
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config SRCU bool help This option selects the sleepable version of RCU. This version permits arbitrary sleeping or blocking within RCU read-side critical sections. |
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config TASKS_RCU |
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bool |
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default n |
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depends on !UML |
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select SRCU |
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help This option enables a task-based RCU implementation that uses only voluntary context switch (not preemption!), idle, and user-mode execution as quiescent states. |
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config RCU_STALL_COMMON |
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def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE ) |
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help This option enables RCU CPU stall code that is common between the TINY and TREE variants of RCU. The purpose is to allow the tiny variants to disable RCU CPU stall warnings, while making these warnings mandatory for the tree variants. |
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config CONTEXT_TRACKING bool |
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config CONTEXT_TRACKING_FORCE bool "Force context tracking" depends on CONTEXT_TRACKING |
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default y if !NO_HZ_FULL |
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help |
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The major pre-requirement for full dynticks to work is to support the context tracking subsystem. But there are also other dependencies to provide in order to make the full dynticks working. This option stands for testing when an arch implements the context tracking backend but doesn't yet fullfill all the requirements to make the full dynticks feature working. Without the full dynticks, there is no way to test the support for context tracking and the subsystems that rely on it: RCU userspace extended quiescent state and tickless cputime accounting. This option copes with the absence of the full dynticks subsystem by forcing the context tracking on all CPUs in the system. |
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Say Y only if you're working on the development of an |
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architecture backend for the context tracking. Say N otherwise, this option brings an overhead that you don't want in production. |
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config RCU_FANOUT int "Tree-based hierarchical RCU fanout value" range 2 64 if 64BIT range 2 32 if !64BIT |
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depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT |
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default 64 if 64BIT default 32 if !64BIT help This option controls the fanout of hierarchical implementations of RCU, allowing RCU to work efficiently on machines with |
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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. |
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Select a specific number if testing RCU itself. Take the default if unsure. |
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config RCU_FANOUT_LEAF int "Tree-based hierarchical RCU leaf-level fanout value" |
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range 2 64 if 64BIT range 2 32 if !64BIT |
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depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT |
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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. |
8bd93a2c5
|
575 576 |
config RCU_FAST_NO_HZ bool "Accelerate last non-dyntick-idle CPU's grace periods" |
78cae10b3
|
577 |
depends on NO_HZ_COMMON && SMP && RCU_EXPERT |
8bd93a2c5
|
578 579 |
default n help |
c0f4dfd4f
|
580 581 582 583 584 585 586 |
This option permits CPUs to enter dynticks-idle state even if they have RCU callbacks queued, and prevents RCU from waking these CPUs up more than roughly once every four jiffies (by default, you can adjust this using the rcutree.rcu_idle_gp_delay parameter), thus improving energy efficiency. On the other hand, this option increases the duration of RCU grace periods, for example, slowing down synchronize_rcu(). |
ba49df476
|
587 |
|
c0f4dfd4f
|
588 589 |
Say Y if energy efficiency is critically important, and you don't care about increased grace-period durations. |
8bd93a2c5
|
590 591 |
Say N if you are unsure. |
c903ff837
|
592 |
config TREE_RCU_TRACE |
28f6569ab
|
593 |
def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU ) |
c903ff837
|
594 595 |
select DEBUG_FS help |
f41d911f8
|
596 |
This option provides tracing for the TREE_RCU and |
28f6569ab
|
597 |
PREEMPT_RCU implementations, permitting Makefile to |
f41d911f8
|
598 |
trivially select kernel/rcutree_trace.c. |
c903ff837
|
599 |
|
24278d148
|
600 601 |
config RCU_BOOST bool "Enable RCU priority boosting" |
78cae10b3
|
602 |
depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT |
24278d148
|
603 604 605 606 607 608 609 610 611 |
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. |
21871d7ef
|
612 613 |
config RCU_KTHREAD_PRIO int "Real-time priority to use for RCU worker threads" |
a94844b22
|
614 615 616 617 |
range 1 99 if RCU_BOOST range 0 99 if !RCU_BOOST default 1 if RCU_BOOST default 0 if !RCU_BOOST |
26730f55c
|
618 |
depends on RCU_EXPERT |
24278d148
|
619 |
help |
21871d7ef
|
620 621 622 623 624 625 626 627 |
This option specifies the SCHED_FIFO priority value that will be assigned to the rcuc/n and rcub/n threads and is also the value used for RCU_BOOST (if enabled). 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_KTHREAD_PRIO to a priority higher than the highest-priority real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO value of 1 is appropriate in the common case, which is real-time |
c9336643e
|
628 629 630 631 632 |
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 |
21871d7ef
|
633 |
that CPU. In this case, you should set RCU_KTHREAD_PRIO to |
c9336643e
|
634 635 636 637 |
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 |
21871d7ef
|
638 |
the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be |
c9336643e
|
639 |
set to priority 6 or higher. |
24278d148
|
640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 |
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. |
3fbfbf7a3
|
655 |
config RCU_NOCB_CPU |
9a5739d73
|
656 |
bool "Offload RCU callback processing from boot-selected CPUs" |
28f6569ab
|
657 |
depends on TREE_RCU || PREEMPT_RCU |
be55fa2ad
|
658 |
depends on RCU_EXPERT || NO_HZ_FULL |
3fbfbf7a3
|
659 660 661 662 663 664 665 666 667 |
default n help Use this option to reduce OS jitter for aggressive HPC or real-time workloads. It can also be used to offload RCU callback invocation to energy-efficient CPUs in battery-powered asymmetric multiprocessors. This option offloads callback invocation from the set of CPUs specified at boot time by the rcu_nocbs parameter. |
a48898585
|
668 669 670 671 672 673 674 |
For each such CPU, a kthread ("rcuox/N") will be created to invoke callbacks, where the "N" is the CPU being offloaded, and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and "s" for RCU-sched. Nothing prevents this kthread from running on the specified CPUs, but (1) the kthreads may be preempted between each callback, and (2) affinity or cgroups can be used to force the kthreads to run on whatever set of CPUs is desired. |
3fbfbf7a3
|
675 |
|
34ed62461
|
676 |
Say Y here if you want to help to debug reduced OS jitter. |
3fbfbf7a3
|
677 |
Say N here if you are unsure. |
911af505e
|
678 679 680 |
choice prompt "Build-forced no-CBs CPUs" default RCU_NOCB_CPU_NONE |
4568779f7
|
681 |
depends on RCU_NOCB_CPU |
911af505e
|
682 |
help |
676c3dc20
|
683 684 685 686 |
This option allows no-CBs CPUs (whose RCU callbacks are invoked from kthreads rather than from softirq context) to be specified at build time. Additional no-CBs CPUs may be specified by the rcu_nocbs= boot parameter. |
911af505e
|
687 688 689 |
config RCU_NOCB_CPU_NONE bool "No build_forced no-CBs CPUs" |
911af505e
|
690 691 692 |
help This option does not force any of the CPUs to be no-CBs CPUs. Only CPUs designated by the rcu_nocbs= boot parameter will be |
676c3dc20
|
693 694 695 696 697 698 699 |
no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU kthreads whose names begin with "rcuo". All other CPUs will invoke their own RCU callbacks in softirq context. Select this option if you want to choose no-CBs CPUs at boot time, for example, to allow testing of different no-CBs configurations without having to rebuild the kernel each time. |
911af505e
|
700 701 702 |
config RCU_NOCB_CPU_ZERO bool "CPU 0 is a build_forced no-CBs CPU" |
911af505e
|
703 |
help |
676c3dc20
|
704 705 706 707 708 709 |
This option forces CPU 0 to be a no-CBs CPU, so that its RCU callbacks are invoked by a per-CPU kthread whose name begins with "rcuo". Additional CPUs may be designated as no-CBs CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs. All other CPUs will invoke their own RCU callbacks in softirq context. |
911af505e
|
710 711 |
Select this if CPU 0 needs to be a no-CBs CPU for real-time |
676c3dc20
|
712 713 |
or energy-efficiency reasons, but the real reason it exists is to ensure that randconfig testing covers mixed systems. |
911af505e
|
714 715 716 |
config RCU_NOCB_CPU_ALL bool "All CPUs are build_forced no-CBs CPUs" |
911af505e
|
717 718 |
help This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= |
676c3dc20
|
719 720 721 722 723 724 |
boot parameter will be ignored. All CPUs' RCU callbacks will be executed in the context of per-CPU rcuo kthreads created for this purpose. Assuming that the kthreads whose names start with "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter on the remaining CPUs, but might decrease memory locality during RCU-callback invocation, thus potentially degrading throughput. |
911af505e
|
725 726 727 728 729 |
Select this if all CPUs need to be no-CBs CPUs for real-time or energy-efficiency reasons. endchoice |
ee42571f4
|
730 731 732 733 734 735 736 737 738 739 740 741 |
config RCU_EXPEDITE_BOOT bool default n help This option enables expedited grace periods at boot time, as if rcu_expedite_gp() had been invoked early in boot. The corresponding rcu_unexpedite_gp() is invoked from rcu_end_inkernel_boot(), which is intended to be invoked at the end of the kernel-only boot sequence, just before init is exec'ed. Accept the default if unsure. |
c903ff837
|
742 |
endmenu # "RCU Subsystem" |
de5b56ba5
|
743 744 745 |
config BUILD_BIN2C bool default n |
1da177e4c
|
746 |
config IKCONFIG |
f2443ab6c
|
747 |
tristate "Kernel .config support" |
de5b56ba5
|
748 |
select BUILD_BIN2C |
1da177e4c
|
749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 |
---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. |
794543a23
|
765 766 |
config LOG_BUF_SHIFT int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" |
fb39f98d1
|
767 |
range 12 25 |
f17a32e97
|
768 |
default 17 |
361e9dfba
|
769 |
depends on PRINTK |
794543a23
|
770 |
help |
23b2899f7
|
771 772 773 774 |
Select the minimal kernel log buffer size as a power of 2. The final size is affected by LOG_CPU_MAX_BUF_SHIFT config parameter, see below. Any higher size also might be forced by "log_buf_len" boot parameter. |
f17a32e97
|
775 |
Examples: |
23b2899f7
|
776 |
17 => 128 KB |
f17a32e97
|
777 |
16 => 64 KB |
23b2899f7
|
778 779 |
15 => 32 KB 14 => 16 KB |
794543a23
|
780 781 |
13 => 8 KB 12 => 4 KB |
23b2899f7
|
782 783 |
config LOG_CPU_MAX_BUF_SHIFT int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" |
2240a31db
|
784 |
depends on SMP |
23b2899f7
|
785 786 787 |
range 0 21 default 12 if !BASE_SMALL default 0 if BASE_SMALL |
361e9dfba
|
788 |
depends on PRINTK |
23b2899f7
|
789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 |
help This option allows to increase the default ring buffer size according to the number of CPUs. The value defines the contribution of each CPU as a power of 2. The used space is typically only few lines however it might be much more when problems are reported, e.g. backtraces. The increased size means that a new buffer has to be allocated and the original static one is unused. It makes sense only on systems with more CPUs. Therefore this value is used only when the sum of contributions is greater than the half of the default kernel ring buffer as defined by LOG_BUF_SHIFT. The default values are set so that more than 64 CPUs are needed to trigger the allocation. Also this option is ignored when "log_buf_len" kernel parameter is used as it forces an exact (power of two) size of the ring buffer. The number of possible CPUs is used for this computation ignoring |
5e0d8d59a
|
807 808 |
hotplugging making the computation optimal for the worst case scenario while allowing a simple algorithm to be used from bootup. |
23b2899f7
|
809 810 811 812 813 814 815 816 |
Examples shift values and their meaning: 17 => 128 KB for each CPU 16 => 64 KB for each CPU 15 => 32 KB for each CPU 14 => 16 KB for each CPU 13 => 8 KB for each CPU 12 => 4 KB for each CPU |
427934b87
|
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 |
config NMI_LOG_BUF_SHIFT int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)" range 10 21 default 13 depends on PRINTK_NMI help Select the size of a per-CPU buffer where NMI messages are temporary stored. They are copied to the main log buffer in a safe context to avoid a deadlock. The value defines the size as a power of 2. NMI messages are rare and limited. The largest one is when a backtrace is printed. It usually fits into 4KB. Select 8KB if you want to be on the safe side. Examples: 17 => 128 KB for each CPU 16 => 64 KB for each CPU 15 => 32 KB for each CPU 14 => 16 KB for each CPU 13 => 8 KB for each CPU 12 => 4 KB for each CPU |
a5574cf65
|
838 839 840 841 842 |
# # Architectures with an unreliable sched_clock() should select this: # config HAVE_UNSTABLE_SCHED_CLOCK bool |
38ff87f77
|
843 844 |
config GENERIC_SCHED_CLOCK bool |
be3a72842
|
845 846 847 848 849 850 |
# # For architectures that want to enable the support for NUMA-affine scheduler # balancing logic: # config ARCH_SUPPORTS_NUMA_BALANCING bool |
be5e610c0
|
851 |
# |
72b252aed
|
852 853 854 855 856 857 858 859 860 861 |
# For architectures that prefer to flush all TLBs after a number of pages # are unmapped instead of sending one IPI per page to flush. The architecture # must provide guarantees on what happens if a clean TLB cache entry is # written after the unmap. Details are in mm/rmap.c near the check for # should_defer_flush. The architecture should also consider if the full flush # and the refill costs are offset by the savings of sending fewer IPIs. config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH bool # |
be5e610c0
|
862 863 864 865 |
# For architectures that know their GCC __int128 support is sound # config ARCH_SUPPORTS_INT128 bool |
be3a72842
|
866 867 868 869 870 |
# For architectures that (ab)use NUMA to represent different memory regions # all cpu-local but of different latencies, such as SuperH. # config ARCH_WANT_NUMA_VARIABLE_LOCALITY bool |
be3a72842
|
871 872 |
config NUMA_BALANCING bool "Memory placement aware NUMA scheduler" |
be3a72842
|
873 874 875 876 877 878 |
depends on ARCH_SUPPORTS_NUMA_BALANCING depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY depends on SMP && NUMA && MIGRATION help This option adds support for automatic NUMA aware memory/task placement. The mechanism is quite primitive and is based on migrating memory when |
6d56a410a
|
879 |
it has references to the node the task is running on. |
be3a72842
|
880 881 |
This system will be inactive on UMA systems. |
6f7c97e80
|
882 883 884 885 886 887 888 |
config NUMA_BALANCING_DEFAULT_ENABLED bool "Automatically enable NUMA aware memory/task placement" default y depends on NUMA_BALANCING help If set, automatic NUMA balancing will be enabled if running on a NUMA machine. |
23964d2d0
|
889 |
menuconfig CGROUPS |
6341e62b2
|
890 |
bool "Control Group support" |
2bd59d48e
|
891 |
select KERNFS |
5cdc38f98
|
892 |
help |
23964d2d0
|
893 |
This option adds support for grouping sets of processes together, for |
5cdc38f98
|
894 895 896 |
use with process control subsystems such as Cpusets, CFS, memory controls or device isolation. See |
5cdc38f98
|
897 |
- Documentation/scheduler/sched-design-CFS.txt (CFS) |
9991a9c8d
|
898 |
- Documentation/cgroup-v1/ (features for grouping, isolation |
45ce80fb6
|
899 |
and resource control) |
5cdc38f98
|
900 901 |
Say N if unsure. |
23964d2d0
|
902 |
if CGROUPS |
3e32cb2e0
|
903 904 |
config PAGE_COUNTER bool |
c255a4580
|
905 |
config MEMCG |
a0166ec4b
|
906 |
bool "Memory controller" |
3e32cb2e0
|
907 |
select PAGE_COUNTER |
79bd9814e
|
908 |
select EVENTFD |
00f0b8259
|
909 |
help |
a0166ec4b
|
910 |
Provides control over the memory footprint of tasks in a cgroup. |
00f0b8259
|
911 |
|
c255a4580
|
912 |
config MEMCG_SWAP |
a0166ec4b
|
913 |
bool "Swap controller" |
c255a4580
|
914 |
depends on MEMCG && SWAP |
c077719be
|
915 |
help |
a0166ec4b
|
916 |
Provides control over the swap space consumed by tasks in a cgroup. |
c255a4580
|
917 |
config MEMCG_SWAP_ENABLED |
a0166ec4b
|
918 |
bool "Swap controller enabled by default" |
c255a4580
|
919 |
depends on MEMCG_SWAP |
a42c390cf
|
920 921 922 923 |
default y help Memory Resource Controller Swap Extension comes with its price in a bigger memory consumption. General purpose distribution kernels |
43d547f9c
|
924 |
which want to enable the feature but keep it disabled by default |
07555ac14
|
925 |
and let the user enable it by swapaccount=1 boot command line |
a42c390cf
|
926 927 928 |
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 |
00a66d297
|
929 |
then swapaccount=0 does the trick). |
c077719be
|
930 |
|
6bf024e69
|
931 932 933 |
config BLK_CGROUP bool "IO controller" depends on BLOCK |
2bc64a204
|
934 |
default n |
6bf024e69
|
935 936 937 938 |
---help--- Generic block IO controller cgroup interface. This is the common cgroup interface which should be used by various IO controlling policies. |
2bc64a204
|
939 |
|
6bf024e69
|
940 941 942 943 |
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. |
e5d1367f1
|
944 |
|
6bf024e69
|
945 946 947 948 949 |
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. |
9991a9c8d
|
950 |
See Documentation/cgroup-v1/blkio-controller.txt for more information. |
6bf024e69
|
951 952 953 954 955 956 957 958 959 960 961 962 963 |
config DEBUG_BLK_CGROUP bool "IO controller debugging" depends on BLK_CGROUP default n ---help--- Enable some debugging help. Currently it exports additional stat files in a cgroup which can be useful for debugging. config CGROUP_WRITEBACK bool depends on MEMCG && BLK_CGROUP default y |
e5d1367f1
|
964 |
|
7c9414385
|
965 |
menuconfig CGROUP_SCHED |
a0166ec4b
|
966 |
bool "CPU controller" |
7c9414385
|
967 968 969 970 971 972 973 974 975 976 977 |
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 |
ab84d31e1
|
978 979 |
config CFS_BANDWIDTH bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" |
ab84d31e1
|
980 981 982 983 984 985 986 987 |
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. |
7c9414385
|
988 989 |
config RT_GROUP_SCHED bool "Group scheduling for SCHED_RR/FIFO" |
7c9414385
|
990 991 992 993 |
depends on CGROUP_SCHED default n help This feature lets you explicitly allocate real CPU bandwidth |
32bd7eb5a
|
994 |
to task groups. If enabled, it will also make it impossible to |
7c9414385
|
995 996 997 998 999 |
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 |
6bf024e69
|
1000 1001 1002 1003 1004 1005 1006 1007 1008 |
config CGROUP_PIDS bool "PIDs controller" help Provides enforcement of process number limits in the scope of a cgroup. Any attempt to fork more processes than is allowed in the cgroup will fail. PIDs are fundamentally a global resource because it is fairly trivial to reach PID exhaustion before you reach even a conservative kmemcg limit. As a result, it is possible to grind a system to halt without being limited by other cgroup policies. The |
6cc578df4
|
1009 |
PIDs controller is designed to stop this from happening. |
6bf024e69
|
1010 1011 |
It should be noted that organisational operations (such as attaching |
6cc578df4
|
1012 |
to a cgroup hierarchy will *not* be blocked by the PIDs controller), |
6bf024e69
|
1013 1014 1015 1016 1017 1018 1019 1020 |
since the PIDs limit only affects a process's ability to fork, not to attach to a cgroup. config CGROUP_FREEZER bool "Freezer controller" help Provides a way to freeze and unfreeze all tasks in a cgroup. |
489c2a20a
|
1021 1022 1023 1024 |
This option affects the ORIGINAL cgroup interface. The cgroup2 memory controller includes important in-kernel memory consumers per default. If you're using cgroup2, say N. |
6bf024e69
|
1025 1026 1027 1028 |
config CGROUP_HUGETLB bool "HugeTLB controller" depends on HUGETLB_PAGE select PAGE_COUNTER |
afc24d49c
|
1029 |
default n |
6bf024e69
|
1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 |
help Provides a cgroup controller for HugeTLB pages. When you enable this, you can put a per cgroup limit on HugeTLB usage. The limit is enforced during page fault. Since HugeTLB doesn't support page reclaim, enforcing the limit at page fault time implies that, the application will get SIGBUS signal if it tries to access HugeTLB pages beyond its limit. This requires the application to know beforehand how much HugeTLB pages it would require for its use. The control group is tracked in the third page lru pointer. This means that we cannot use the controller with huge page less than 3 pages. |
afc24d49c
|
1040 |
|
6bf024e69
|
1041 1042 1043 1044 1045 1046 1047 |
config CPUSETS bool "Cpuset controller" 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. |
afc24d49c
|
1048 |
|
6bf024e69
|
1049 |
Say N if unsure. |
afc24d49c
|
1050 |
|
6bf024e69
|
1051 1052 1053 1054 |
config PROC_PID_CPUSET bool "Include legacy /proc/<pid>/cpuset file" depends on CPUSETS default y |
afc24d49c
|
1055 |
|
6bf024e69
|
1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 |
config CGROUP_DEVICE bool "Device controller" help Provides a cgroup controller implementing whitelists for devices which a process in the cgroup can mknod or open. config CGROUP_CPUACCT bool "Simple CPU accounting controller" help Provides a simple controller for monitoring the total CPU consumed by the tasks in a cgroup. config CGROUP_PERF bool "Perf controller" depends on PERF_EVENTS help This option extends the perf per-cpu mode to restrict monitoring to threads which belong to the cgroup specified and run on the designated cpu. Say N if unsure. config CGROUP_DEBUG bool "Example controller" |
afc24d49c
|
1080 |
default n |
6bf024e69
|
1081 1082 1083 |
help This option enables a simple controller that exports debugging information about the cgroups framework. |
afc24d49c
|
1084 |
|
6bf024e69
|
1085 |
Say N. |
89e9b9e07
|
1086 |
|
23964d2d0
|
1087 |
endif # CGROUPS |
c077719be
|
1088 |
|
067bce1a0
|
1089 1090 |
config CHECKPOINT_RESTORE bool "Checkpoint/restore support" if EXPERT |
2e13ba54a
|
1091 |
select PROC_CHILDREN |
067bce1a0
|
1092 1093 1094 1095 1096 1097 1098 1099 |
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. |
8dd2a82c2
|
1100 |
menuconfig NAMESPACES |
6a108a14f
|
1101 |
bool "Namespaces support" if EXPERT |
2813893f8
|
1102 |
depends on MULTIUSER |
6a108a14f
|
1103 |
default !EXPERT |
c5289a694
|
1104 1105 1106 1107 1108 |
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. |
8dd2a82c2
|
1109 |
if NAMESPACES |
58bfdd6de
|
1110 1111 |
config UTS_NS bool "UTS namespace" |
17a6d4411
|
1112 |
default y |
58bfdd6de
|
1113 1114 1115 |
help In this namespace tasks see different info provided with the uname() system call |
ae5e1b22f
|
1116 1117 |
config IPC_NS bool "IPC namespace" |
8dd2a82c2
|
1118 |
depends on (SYSVIPC || POSIX_MQUEUE) |
17a6d4411
|
1119 |
default y |
ae5e1b22f
|
1120 1121 |
help In this namespace tasks work with IPC ids which correspond to |
614b84cf4
|
1122 |
different IPC objects in different namespaces. |
ae5e1b22f
|
1123 |
|
aee16ce73
|
1124 |
config USER_NS |
19c923998
|
1125 |
bool "User namespace" |
5673a94c1
|
1126 |
default n |
aee16ce73
|
1127 1128 1129 |
help This allows containers, i.e. vservers, to use user namespaces to provide different user info for different servers. |
e11f0ae38
|
1130 1131 |
When user namespaces are enabled in the kernel it is |
d886f4e48
|
1132 1133 1134 |
recommended that the MEMCG option also be enabled and that user-space use the memory control groups to limit the amount of memory a memory unprivileged users can use. |
e11f0ae38
|
1135 |
|
aee16ce73
|
1136 |
If unsure, say N. |
74bd59bb3
|
1137 |
config PID_NS |
9bd38c2cd
|
1138 |
bool "PID Namespaces" |
17a6d4411
|
1139 |
default y |
74bd59bb3
|
1140 |
help |
12d2b8f95
|
1141 |
Support process id namespaces. This allows having multiple |
692105b8a
|
1142 |
processes with the same pid as long as they are in different |
74bd59bb3
|
1143 |
pid namespaces. This is a building block of containers. |
d6eb633fe
|
1144 1145 |
config NET_NS bool "Network namespace" |
8dd2a82c2
|
1146 |
depends on NET |
17a6d4411
|
1147 |
default y |
d6eb633fe
|
1148 1149 1150 |
help Allow user space to create what appear to be multiple instances of the network stack. |
8dd2a82c2
|
1151 |
endif # NAMESPACES |
5091faa44
|
1152 1153 |
config SCHED_AUTOGROUP bool "Automatic process group scheduling" |
5091faa44
|
1154 1155 1156 1157 1158 1159 1160 1161 1162 |
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. |
7af37bec4
|
1163 |
config SYSFS_DEPRECATED |
5d6a4ea57
|
1164 |
bool "Enable deprecated sysfs features to support old userspace tools" |
7af37bec4
|
1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 |
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 |
5d6a4ea57
|
1187 |
bool "Enable deprecated sysfs features by default" |
7af37bec4
|
1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 |
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)" |
26b5679e4
|
1203 |
select IRQ_WORK |
7af37bec4
|
1204 1205 1206 1207 1208 1209 1210 1211 |
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. |
f991633de
|
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 |
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. |
c33df4eaa
|
1227 |
if BLK_DEV_INITRD |
dbec48663
|
1228 |
source "usr/Kconfig" |
c33df4eaa
|
1229 |
endif |
877417e6f
|
1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 |
choice prompt "Compiler optimization level" default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE config CC_OPTIMIZE_FOR_PERFORMANCE bool "Optimize for performance" help This is the default optimization level for the kernel, building with the "-O2" compiler flag for best performance and most helpful compile-time warnings. |
c45b4f1f1
|
1240 |
config CC_OPTIMIZE_FOR_SIZE |
96fffeb4b
|
1241 |
bool "Optimize for size" |
c45b4f1f1
|
1242 |
help |
31a4af7f7
|
1243 1244 |
Enabling this option will pass "-Os" instead of "-O2" to your compiler resulting in a smaller kernel. |
c45b4f1f1
|
1245 |
|
3a55fb0d9
|
1246 |
If unsure, say N. |
c45b4f1f1
|
1247 |
|
877417e6f
|
1248 |
endchoice |
0847062ad
|
1249 1250 |
config SYSCTL bool |
b943c460f
|
1251 1252 |
config ANON_INODES bool |
657a52095
|
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 |
config HAVE_UID16 bool config SYSCTL_EXCEPTION_TRACE bool help Enable support for /proc/sys/debug/exception-trace. config SYSCTL_ARCH_UNALIGN_NO_WARN bool help Enable support for /proc/sys/kernel/ignore-unaligned-usertrap Allows arch to define/use @no_unaligned_warning to possibly warn about unaligned access emulation going on under the hood. config SYSCTL_ARCH_UNALIGN_ALLOW bool help Enable support for /proc/sys/kernel/unaligned-trap Allows arches to define/use @unaligned_enabled to runtime toggle the unaligned access emulation. see arch/parisc/kernel/unaligned.c for reference |
657a52095
|
1275 1276 |
config HAVE_PCSPKR_PLATFORM bool |
f89b7755f
|
1277 1278 1279 |
# interpreter that classic socket filters depend on config BPF bool |
6a108a14f
|
1280 1281 |
menuconfig EXPERT bool "Configure standard kernel features (expert users)" |
f505c553d
|
1282 1283 |
# Unhide debug options, to make the on-by-default options visible select DEBUG_KERNEL |
1da177e4c
|
1284 1285 1286 1287 1288 |
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. |
ae81f9e37
|
1289 |
config UID16 |
6a108a14f
|
1290 |
bool "Enable 16-bit UID system calls" if EXPERT |
2813893f8
|
1291 |
depends on HAVE_UID16 && MULTIUSER |
ae81f9e37
|
1292 1293 1294 |
default y help This enables the legacy 16-bit UID syscall wrappers. |
2813893f8
|
1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 |
config MULTIUSER bool "Multiple users, groups and capabilities support" if EXPERT default y help This option enables support for non-root users, groups and capabilities. If you say N here, all processes will run with UID 0, GID 0, and all possible capabilities. Saying N here also compiles out support for system calls related to UIDs, GIDs, and capabilities, such as setuid, setgid, and capset. If unsure, say Y here. |
f6187769d
|
1308 1309 1310 1311 1312 1313 1314 1315 1316 |
config SGETMASK_SYSCALL bool "sgetmask/ssetmask syscalls support" if EXPERT def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH ---help--- sys_sgetmask and sys_ssetmask are obsolete system calls no longer supported in libc but still enabled by default in some architectures. If unsure, leave the default option here. |
6af9f7bf3
|
1317 1318 1319 1320 1321 1322 1323 1324 1325 |
config SYSFS_SYSCALL bool "Sysfs syscall support" if EXPERT default y ---help--- sys_sysfs is an obsolete system call no longer supported in libc. Note that disabling this option is more secure but might break compatibility with some systems. If unsure say Y here. |
b89a81712
|
1326 |
config SYSCTL_SYSCALL |
6a108a14f
|
1327 |
bool "Sysctl syscall support" if EXPERT |
26a7034b4
|
1328 |
depends on PROC_SYSCTL |
c736de60a
|
1329 |
default n |
b89a81712
|
1330 |
select SYSCTL |
ae81f9e37
|
1331 |
---help--- |
13bb7e37e
|
1332 1333 1334 1335 |
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. |
b89a81712
|
1336 |
|
13bb7e37e
|
1337 1338 1339 |
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. |
b89a81712
|
1340 |
|
c736de60a
|
1341 |
If unsure say N here. |
ae81f9e37
|
1342 |
|
1da177e4c
|
1343 |
config KALLSYMS |
6a108a14f
|
1344 |
bool "Load all symbols for debugging/ksymoops" if EXPERT |
1da177e4c
|
1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 |
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 |
71a83ec7d
|
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 |
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. |
d59745ce3
|
1367 |
|
4d5d5664c
|
1368 1369 |
config KALLSYMS_ABSOLUTE_PERCPU bool |
076501ff6
|
1370 |
depends on KALLSYMS |
4d5d5664c
|
1371 |
default X86_64 && SMP |
2213e9a66
|
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 |
config KALLSYMS_BASE_RELATIVE bool depends on KALLSYMS default !IA64 && !(TILE && 64BIT) help Instead of emitting them as absolute values in the native word size, emit the symbol references in the kallsyms table as 32-bit entries, each containing a relative value in the range [base, base + U32_MAX] or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either an absolute value in the range [0, S32_MAX] or a relative value in the range [base, base + S32_MAX], where base is the lowest relative symbol address encountered in the image. On 64-bit builds, this reduces the size of the address table by 50%, but more importantly, it results in entries whose values are build time constants, and no relocation pass is required at runtime to fix up the entries based on the runtime load address of the kernel. |
d59745ce3
|
1389 1390 |
config PRINTK default y |
6a108a14f
|
1391 |
bool "Enable support for printk" if EXPERT |
74876a98a
|
1392 |
select IRQ_WORK |
d59745ce3
|
1393 1394 1395 1396 1397 1398 |
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. |
42a0bb3f7
|
1399 1400 1401 1402 |
config PRINTK_NMI def_bool y depends on PRINTK depends on HAVE_NMI |
c8538a7aa
|
1403 |
config BUG |
6a108a14f
|
1404 |
bool "BUG() support" if EXPERT |
c8538a7aa
|
1405 1406 1407 1408 1409 1410 1411 |
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. |
708e9a794
|
1412 |
config ELF_CORE |
046d662f4
|
1413 |
depends on COREDUMP |
708e9a794
|
1414 |
default y |
6a108a14f
|
1415 |
bool "Enable ELF core dumps" if EXPERT |
708e9a794
|
1416 1417 |
help Enable support for generating core dumps. Disabling saves about 4k. |
8761f1ab7
|
1418 |
|
e5e1d3cb2
|
1419 |
config PCSPKR_PLATFORM |
6a108a14f
|
1420 |
bool "Enable PC-Speaker support" if EXPERT |
8761f1ab7
|
1421 |
depends on HAVE_PCSPKR_PLATFORM |
15f304b66
|
1422 |
select I8253_LOCK |
e5e1d3cb2
|
1423 1424 1425 1426 |
default y help This option allows to disable the internal PC-Speaker support, saving some memory. |
1da177e4c
|
1427 1428 |
config BASE_FULL default y |
6a108a14f
|
1429 |
bool "Enable full-sized data structures for core" if EXPERT |
1da177e4c
|
1430 1431 1432 1433 1434 1435 |
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 |
6a108a14f
|
1436 |
bool "Enable futex support" if EXPERT |
1da177e4c
|
1437 |
default y |
23f78d4a0
|
1438 |
select RT_MUTEXES |
1da177e4c
|
1439 1440 1441 1442 |
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. |
03b8c7b62
|
1443 1444 |
config HAVE_FUTEX_CMPXCHG bool |
62b4d2041
|
1445 |
depends on FUTEX |
03b8c7b62
|
1446 1447 1448 1449 |
help Architectures should select this if futex_atomic_cmpxchg_inatomic() is implemented and always working. This removes a couple of runtime checks. |
1da177e4c
|
1450 |
config EPOLL |
6a108a14f
|
1451 |
bool "Enable eventpoll support" if EXPERT |
1da177e4c
|
1452 |
default y |
448e3cee8
|
1453 |
select ANON_INODES |
1da177e4c
|
1454 1455 1456 |
help Disabling this option will cause the kernel to be built without support for epoll family of system calls. |
fba2afaae
|
1457 |
config SIGNALFD |
6a108a14f
|
1458 |
bool "Enable signalfd() system call" if EXPERT |
448e3cee8
|
1459 |
select ANON_INODES |
fba2afaae
|
1460 1461 1462 1463 1464 1465 |
default y help Enable the signalfd() system call that allows to receive signals on a file descriptor. If unsure, say Y. |
b215e2839
|
1466 |
config TIMERFD |
6a108a14f
|
1467 |
bool "Enable timerfd() system call" if EXPERT |
448e3cee8
|
1468 |
select ANON_INODES |
b215e2839
|
1469 1470 1471 1472 1473 1474 |
default y help Enable the timerfd() system call that allows to receive timer events on a file descriptor. If unsure, say Y. |
e1ad7468c
|
1475 |
config EVENTFD |
6a108a14f
|
1476 |
bool "Enable eventfd() system call" if EXPERT |
448e3cee8
|
1477 |
select ANON_INODES |
e1ad7468c
|
1478 1479 1480 1481 1482 1483 |
default y help Enable the eventfd() system call that allows to receive both kernel notification (ie. KAIO) or userspace notifications. If unsure, say Y. |
f89b7755f
|
1484 1485 |
# syscall, maps, verifier config BPF_SYSCALL |
e1abf2cc8
|
1486 |
bool "Enable bpf() system call" |
f89b7755f
|
1487 1488 1489 1490 1491 1492 |
select ANON_INODES select BPF default n help Enable the bpf() system call that allows to manipulate eBPF programs and maps via file descriptors. |
1da177e4c
|
1493 |
config SHMEM |
6a108a14f
|
1494 |
bool "Use full shmem filesystem" if EXPERT |
1da177e4c
|
1495 1496 1497 1498 1499 1500 1501 1502 |
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. |
ebf3f09c6
|
1503 |
config AIO |
6a108a14f
|
1504 |
bool "Enable AIO support" if EXPERT |
ebf3f09c6
|
1505 1506 1507 |
default y help This option enables POSIX asynchronous I/O which may by used |
657a52095
|
1508 1509 |
by some high performance threaded applications. Disabling this option saves about 7k. |
d3ac21cac
|
1510 1511 1512 1513 1514 1515 1516 1517 1518 |
config ADVISE_SYSCALLS bool "Enable madvise/fadvise syscalls" if EXPERT default y help This option enables the madvise and fadvise syscalls, used by applications to advise the kernel about their future memory or file usage, improving performance. If building an embedded system where no applications use these syscalls, you can disable this option to save space. |
a14c151e5
|
1519 1520 1521 |
config USERFAULTFD bool "Enable userfaultfd() system call" select ANON_INODES |
a14c151e5
|
1522 1523 1524 1525 |
depends on MMU help Enable the userfaultfd() system call that allows to intercept and handle page faults in userland. |
657a52095
|
1526 1527 1528 1529 1530 1531 1532 1533 |
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. |
ebf3f09c6
|
1534 |
|
5b25b13ab
|
1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 |
config MEMBARRIER bool "Enable membarrier() system call" if EXPERT default y help Enable the membarrier() system call that allows issuing memory barriers across all running threads, which can be used to distribute the cost of user-space memory barriers asymmetrically by transforming pairs of memory barriers into pairs consisting of membarrier() and a compiler barrier. If unsure, say Y. |
6befe5f69
|
1546 1547 |
config EMBEDDED bool "Embedded system" |
5d2acfc7b
|
1548 |
option allnoconfig_y |
6befe5f69
|
1549 1550 1551 1552 1553 |
select EXPERT help This option should be enabled if compiling the kernel for an embedded system so certain expert options are available for configuration. |
cdd6c482c
|
1554 |
config HAVE_PERF_EVENTS |
0793a61d4
|
1555 |
bool |
018df72dd
|
1556 1557 |
help See tools/perf/design.txt for details. |
0793a61d4
|
1558 |
|
906010b21
|
1559 1560 1561 1562 |
config PERF_USE_VMALLOC bool help See tools/perf/design.txt for details |
57c0c15b5
|
1563 |
menu "Kernel Performance Events And Counters" |
0793a61d4
|
1564 |
|
cdd6c482c
|
1565 |
config PERF_EVENTS |
57c0c15b5
|
1566 |
bool "Kernel performance events and counters" |
392d65a9a
|
1567 |
default y if PROFILING |
cdd6c482c
|
1568 |
depends on HAVE_PERF_EVENTS |
4c59e4676
|
1569 |
select ANON_INODES |
e360adbe2
|
1570 |
select IRQ_WORK |
83fe27ea5
|
1571 |
select SRCU |
0793a61d4
|
1572 |
help |
57c0c15b5
|
1573 1574 |
Enable kernel support for various performance events provided by software and hardware. |
0793a61d4
|
1575 |
|
dd77038d2
|
1576 |
Software events are supported either built-in or via the |
57c0c15b5
|
1577 |
use of generic tracepoints. |
0793a61d4
|
1578 |
|
57c0c15b5
|
1579 1580 |
Most modern CPUs support performance events via performance counter registers. These registers count the number of certain |
0793a61d4
|
1581 1582 1583 1584 1585 |
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. |
57c0c15b5
|
1586 |
The Linux Performance Event subsystem provides an abstraction of |
dd77038d2
|
1587 |
these software and hardware event capabilities, available via a |
57c0c15b5
|
1588 |
system call and used by the "perf" utility in tools/perf/. It |
0793a61d4
|
1589 1590 1591 1592 |
provides per task and per CPU counters, and it provides event capabilities on top of those. Say Y if unsure. |
906010b21
|
1593 1594 1595 |
config DEBUG_PERF_USE_VMALLOC default n bool "Debug: use vmalloc to back perf mmap() buffers" |
cb3071137
|
1596 |
depends on PERF_EVENTS && DEBUG_KERNEL && !PPC |
906010b21
|
1597 1598 1599 1600 1601 1602 1603 1604 |
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. |
0793a61d4
|
1605 |
endmenu |
f8891e5e1
|
1606 1607 |
config VM_EVENT_COUNTERS default y |
6a108a14f
|
1608 |
bool "Enable VM event counters for /proc/vmstat" if EXPERT |
f8891e5e1
|
1609 |
help |
2aea4fb61
|
1610 1611 |
VM event counters are needed for event counts to be shown. This option allows the disabling of the VM event counters |
6a108a14f
|
1612 |
on EXPERT systems. /proc/vmstat will only show page counts |
2aea4fb61
|
1613 |
if VM event counters are disabled. |
f8891e5e1
|
1614 |
|
41ecc55b8
|
1615 1616 |
config SLUB_DEBUG default y |
6a108a14f
|
1617 |
bool "Enable SLUB debugging support" if EXPERT |
f6acb6350
|
1618 |
depends on SLUB && SYSFS |
41ecc55b8
|
1619 1620 1621 1622 1623 |
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. |
b943c460f
|
1624 1625 1626 1627 1628 1629 1630 |
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 |
692105b8a
|
1631 |
disabled, and can be overridden at runtime by setting |
b943c460f
|
1632 1633 1634 |
/proc/sys/kernel/randomize_va_space to 2. On non-ancient distros (post-2000 ones) N is usually a safe choice. |
81819f0fc
|
1635 1636 |
choice prompt "Choose SLAB allocator" |
a0acd8208
|
1637 |
default SLUB |
81819f0fc
|
1638 1639 1640 1641 1642 |
help This option allows to select a slab allocator. config SLAB bool "SLAB" |
04385fc5e
|
1643 |
select HAVE_HARDENED_USERCOPY_ALLOCATOR |
81819f0fc
|
1644 1645 |
help The regular slab allocator that is established and known to work |
34013886e
|
1646 |
well in all environments. It organizes cache hot objects in |
02f562104
|
1647 |
per cpu and per node queues. |
81819f0fc
|
1648 1649 |
config SLUB |
81819f0fc
|
1650 |
bool "SLUB (Unqueued Allocator)" |
ed18adc1c
|
1651 |
select HAVE_HARDENED_USERCOPY_ALLOCATOR |
81819f0fc
|
1652 1653 1654 1655 1656 |
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 |
02f562104
|
1657 1658 |
and has enhanced diagnostics. SLUB is the default choice for a slab allocator. |
81819f0fc
|
1659 1660 |
config SLOB |
6a108a14f
|
1661 |
depends on EXPERT |
81819f0fc
|
1662 1663 |
bool "SLOB (Simple Allocator)" help |
372914582
|
1664 1665 1666 |
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. |
81819f0fc
|
1667 1668 |
endchoice |
c7ce4f60a
|
1669 1670 |
config SLAB_FREELIST_RANDOM default n |
210e7a43f
|
1671 |
depends on SLAB || SLUB |
c7ce4f60a
|
1672 1673 |
bool "SLAB freelist randomization" help |
210e7a43f
|
1674 |
Randomizes the freelist order used on creating new pages. This |
c7ce4f60a
|
1675 1676 |
security feature reduces the predictability of the kernel slab allocator against heap overflows. |
345c905d1
|
1677 1678 |
config SLUB_CPU_PARTIAL default y |
b39ffbf8b
|
1679 |
depends on SLUB && SMP |
345c905d1
|
1680 1681 1682 1683 1684 1685 1686 |
bool "SLUB per cpu partial cache" help Per cpu partial caches accellerate objects allocation and freeing that is local to a processor at the price of more indeterminism in the latency of the free. On overflow these caches will be cleared which requires the taking of locks that may cause latency spikes. Typically one would choose no for a realtime system. |
ea6376395
|
1687 1688 |
config MMAP_ALLOW_UNINITIALIZED bool "Allow mmapped anonymous memory to be uninitialized" |
6a108a14f
|
1689 |
depends on EXPERT && !MMU |
ea6376395
|
1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 |
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. |
091f6e26e
|
1708 1709 1710 1711 1712 |
config SYSTEM_DATA_VERIFICATION def_bool n select SYSTEM_TRUSTED_KEYRING select KEYS select CRYPTO |
d43de6c78
|
1713 |
select CRYPTO_RSA |
091f6e26e
|
1714 1715 |
select ASYMMETRIC_KEY_TYPE select ASYMMETRIC_PUBLIC_KEY_SUBTYPE |
091f6e26e
|
1716 1717 1718 1719 |
select ASN1 select OID_REGISTRY select X509_CERTIFICATE_PARSER select PKCS7_MESSAGE_PARSER |
82c04ff89
|
1720 |
help |
091f6e26e
|
1721 1722 1723 1724 |
Provide PKCS#7 message verification using the contents of the system trusted keyring to provide public keys. This then can be used for module verification, kexec image verification and firmware blob verification. |
82c04ff89
|
1725 |
|
125e56458
|
1726 |
config PROFILING |
b309a294e
|
1727 |
bool "Profiling support" |
125e56458
|
1728 1729 1730 |
help Say Y here to enable the extended profiling support mechanisms used by profilers such as OProfile. |
5f87f1121
|
1731 1732 1733 1734 |
# # Place an empty function call at each tracepoint site. Can be # dynamically changed for a probe function. # |
97e1c18e8
|
1735 |
config TRACEPOINTS |
5f87f1121
|
1736 |
bool |
97e1c18e8
|
1737 |
|
fb32e03fd
|
1738 |
source "arch/Kconfig" |
1da177e4c
|
1739 |
endmenu # General setup |
ee7e5516b
|
1740 1741 1742 |
config HAVE_GENERIC_DMA_COHERENT bool default n |
158a96242
|
1743 1744 1745 |
config SLABINFO bool depends on PROC_FS |
0f389ec63
|
1746 |
depends on SLAB || SLUB_DEBUG |
158a96242
|
1747 |
default y |
ae81f9e37
|
1748 |
config RT_MUTEXES |
6341e62b2
|
1749 |
bool |
ae81f9e37
|
1750 |
|
1da177e4c
|
1751 1752 1753 1754 |
config BASE_SMALL int default 0 if BASE_FULL default 1 if !BASE_FULL |
66da57332
|
1755 |
menuconfig MODULES |
1da177e4c
|
1756 |
bool "Enable loadable module support" |
11097a036
|
1757 |
option modules |
1da177e4c
|
1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 |
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. |
0b0de1443
|
1775 |
if MODULES |
826e4506a
|
1776 1777 |
config MODULE_FORCE_LOAD bool "Forced module loading" |
826e4506a
|
1778 1779 |
default n help |
91e37a793
|
1780 1781 1782 |
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. |
826e4506a
|
1783 |
|
1da177e4c
|
1784 1785 |
config MODULE_UNLOAD bool "Module unloading" |
1da177e4c
|
1786 1787 1788 |
help Without this option you will not be able to unload any modules (note that some modules may not be unloadable |
f7f5b6755
|
1789 1790 |
anyway), which makes your kernel smaller, faster and simpler. If unsure, say Y. |
1da177e4c
|
1791 1792 1793 |
config MODULE_FORCE_UNLOAD bool "Forced module unloading" |
19c923998
|
1794 |
depends on MODULE_UNLOAD |
1da177e4c
|
1795 1796 1797 1798 1799 1800 |
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. |
1da177e4c
|
1801 |
config MODVERSIONS |
0d5416433
|
1802 |
bool "Module versioning support" |
1da177e4c
|
1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 |
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" |
1da177e4c
|
1813 1814 1815 1816 1817 1818 1819 1820 |
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. |
106a4ee25
|
1821 1822 1823 |
config MODULE_SIG bool "Module signature verification" depends on MODULES |
091f6e26e
|
1824 |
select SYSTEM_DATA_VERIFICATION |
106a4ee25
|
1825 1826 1827 1828 |
help Check modules for valid signatures upon load: the signature is simply appended to the module. For more information see Documentation/module-signing.txt. |
228c37ff9
|
1829 1830 1831 |
Note that this option adds the OpenSSL development packages as a kernel build dependency so that the signing tool can use its crypto library. |
ea0b6dcf7
|
1832 1833 1834 1835 |
!!!WARNING!!! If you enable this option, you MUST make sure that the module DOES NOT get stripped after being signed. This includes the debuginfo strip done by some packagers (such as rpmbuild) and inclusion into an initramfs that wants the module size reduced. |
106a4ee25
|
1836 1837 1838 1839 1840 1841 |
config MODULE_SIG_FORCE bool "Require modules to be validly signed" depends on MODULE_SIG help Reject unsigned modules or signed modules for which we don't have a key. Without this, such modules will simply taint the kernel. |
ea0b6dcf7
|
1842 |
|
d9d8d7ed4
|
1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 |
config MODULE_SIG_ALL bool "Automatically sign all modules" default y depends on MODULE_SIG help Sign all modules during make modules_install. Without this option, modules must be signed manually, using the scripts/sign-file tool. comment "Do not forget to sign required modules with scripts/sign-file" depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL |
ea0b6dcf7
|
1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 |
choice prompt "Which hash algorithm should modules be signed with?" depends on MODULE_SIG help This determines which sort of hashing algorithm will be used during signature generation. This algorithm _must_ be built into the kernel directly so that signature verification can take place. It is not possible to load a signed module containing the algorithm to check the signature on that module. config MODULE_SIG_SHA1 bool "Sign modules with SHA-1" select CRYPTO_SHA1 config MODULE_SIG_SHA224 bool "Sign modules with SHA-224" select CRYPTO_SHA256 config MODULE_SIG_SHA256 bool "Sign modules with SHA-256" select CRYPTO_SHA256 config MODULE_SIG_SHA384 bool "Sign modules with SHA-384" select CRYPTO_SHA512 config MODULE_SIG_SHA512 bool "Sign modules with SHA-512" select CRYPTO_SHA512 endchoice |
227536740
|
1884 1885 1886 1887 1888 1889 1890 1891 |
config MODULE_SIG_HASH string depends on MODULE_SIG default "sha1" if MODULE_SIG_SHA1 default "sha224" if MODULE_SIG_SHA224 default "sha256" if MODULE_SIG_SHA256 default "sha384" if MODULE_SIG_SHA384 default "sha512" if MODULE_SIG_SHA512 |
beb50df39
|
1892 1893 1894 1895 |
config MODULE_COMPRESS bool "Compress modules on installation" depends on MODULES help |
beb50df39
|
1896 |
|
b6c09b512
|
1897 1898 |
Compresses kernel modules when 'make modules_install' is run; gzip or xz depending on "Compression algorithm" below. |
beb50df39
|
1899 |
|
b6c09b512
|
1900 |
module-init-tools MAY support gzip, and kmod MAY support gzip and xz. |
beb50df39
|
1901 |
|
b6c09b512
|
1902 1903 |
Out-of-tree kernel modules installed using Kbuild will also be compressed upon installation. |
beb50df39
|
1904 |
|
b6c09b512
|
1905 1906 |
Note: for modules inside an initrd or initramfs, it's more efficient to compress the whole initrd or initramfs instead. |
beb50df39
|
1907 |
|
b6c09b512
|
1908 1909 1910 |
Note: This is fully compatible with signed modules. If in doubt, say N. |
beb50df39
|
1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 |
choice prompt "Compression algorithm" depends on MODULE_COMPRESS default MODULE_COMPRESS_GZIP help This determines which sort of compression will be used during 'make modules_install'. GZIP (default) and XZ are supported. config MODULE_COMPRESS_GZIP bool "GZIP" config MODULE_COMPRESS_XZ bool "XZ" endchoice |
dbacb0ef6
|
1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 |
config TRIM_UNUSED_KSYMS bool "Trim unused exported kernel symbols" depends on MODULES && !UNUSED_SYMBOLS help The kernel and some modules make many symbols available for other modules to use via EXPORT_SYMBOL() and variants. Depending on the set of modules being selected in your kernel configuration, many of those exported symbols might never be used. This option allows for unused exported symbols to be dropped from the build. In turn, this provides the compiler more opportunities (especially when using LTO) for optimizing the code and reducing binary size. This might have some security advantages as well. |
f1cb637e7
|
1942 |
If unsure, or if you need to build out-of-tree modules, say N. |
dbacb0ef6
|
1943 |
|
0b0de1443
|
1944 |
endif # MODULES |
6c9692e2d
|
1945 1946 1947 |
config MODULES_TREE_LOOKUP def_bool y depends on PERF_EVENTS || TRACING |
98a79d6a5
|
1948 1949 1950 |
config INIT_ALL_POSSIBLE bool help |
5f054e31c
|
1951 1952 |
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 |
98a79d6a5
|
1953 1954 |
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 |
692105b8a
|
1955 |
and have several arch maintainers pursuing me down dark alleys. |
98a79d6a5
|
1956 |
|
3a65dfe8c
|
1957 |
source "block/Kconfig" |
e98c32029
|
1958 1959 1960 |
config PREEMPT_NOTIFIERS bool |
e260be673
|
1961 |
|
16295bec6
|
1962 1963 1964 |
config PADATA depends on SMP bool |
4520c6a49
|
1965 1966 1967 1968 1969 1970 1971 |
config ASN1 tristate help Build a simple ASN.1 grammar compiler that produces a bytecode output that can be interpreted by the ASN.1 stream decoder and used to inform it as to what tags are to be expected in a stream and what functions to call on what tags. |
6beb00092
|
1972 |
source "kernel/Kconfig.locks" |