| config ARCH |
| string |
| option env="ARCH" |
| |
| config KERNELVERSION |
| string |
| option env="KERNELVERSION" |
| |
| config DEFCONFIG_LIST |
| string |
| depends on !UML |
| option defconfig_list |
| default "/lib/modules/$UNAME_RELEASE/.config" |
| default "/etc/kernel-config" |
| default "/boot/config-$UNAME_RELEASE" |
| default "$ARCH_DEFCONFIG" |
| default "arch/$ARCH/defconfig" |
| |
| config CONSTRUCTORS |
| bool |
| depends on !UML |
| default y |
| |
| menu "General setup" |
| |
| config EXPERIMENTAL |
| bool "Prompt for development and/or incomplete code/drivers" |
| ---help--- |
| Some of the various things that Linux supports (such as network |
| drivers, file systems, network protocols, etc.) can be in a state |
| of development where the functionality, stability, or the level of |
| testing is not yet high enough for general use. This is usually |
| known as the "alpha-test" phase among developers. If a feature is |
| currently in alpha-test, then the developers usually discourage |
| uninformed widespread use of this feature by the general public to |
| avoid "Why doesn't this work?" type mail messages. However, active |
| testing and use of these systems is welcomed. Just be aware that it |
| may not meet the normal level of reliability or it may fail to work |
| in some special cases. Detailed bug reports from people familiar |
| with the kernel internals are usually welcomed by the developers |
| (before submitting bug reports, please read the documents |
| <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, |
| <file:Documentation/BUG-HUNTING>, and |
| <file:Documentation/oops-tracing.txt> in the kernel source). |
| |
| This option will also make obsoleted drivers available. These are |
| drivers that have been replaced by something else, and/or are |
| scheduled to be removed in a future kernel release. |
| |
| Unless you intend to help test and develop a feature or driver that |
| falls into this category, or you have a situation that requires |
| using these features, you should probably say N here, which will |
| cause the configurator to present you with fewer choices. If |
| you say Y here, you will be offered the choice of using features or |
| drivers that are currently considered to be in the alpha-test phase. |
| |
| config BROKEN |
| bool |
| |
| config BROKEN_ON_SMP |
| bool |
| depends on BROKEN || !SMP |
| default y |
| |
| config LOCK_KERNEL |
| bool |
| depends on SMP || PREEMPT |
| default y |
| |
| config INIT_ENV_ARG_LIMIT |
| int |
| default 32 if !UML |
| default 128 if UML |
| help |
| Maximum of each of the number of arguments and environment |
| variables passed to init from the kernel command line. |
| |
| |
| config LOCALVERSION |
| string "Local version - append to kernel release" |
| help |
| Append an extra string to the end of your kernel version. |
| This will show up when you type uname, for example. |
| The string you set here will be appended after the contents of |
| any files with a filename matching localversion* in your |
| object and source tree, in that order. Your total string can |
| be a maximum of 64 characters. |
| |
| config LOCALVERSION_AUTO |
| bool "Automatically append version information to the version string" |
| default y |
| help |
| This will try to automatically determine if the current tree is a |
| release tree by looking for git tags that belong to the current |
| top of tree revision. |
| |
| A string of the format -gxxxxxxxx will be added to the localversion |
| if a git-based tree is found. The string generated by this will be |
| appended after any matching localversion* files, and after the value |
| set in CONFIG_LOCALVERSION. |
| |
| (The actual string used here is the first eight characters produced |
| by running the command: |
| |
| $ git rev-parse --verify HEAD |
| |
| which is done within the script "scripts/setlocalversion".) |
| |
| config HAVE_KERNEL_GZIP |
| bool |
| |
| config HAVE_KERNEL_BZIP2 |
| bool |
| |
| config HAVE_KERNEL_LZMA |
| bool |
| |
| config HAVE_KERNEL_LZO |
| bool |
| |
| choice |
| prompt "Kernel compression mode" |
| default KERNEL_GZIP |
| depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO |
| help |
| The linux kernel is a kind of self-extracting executable. |
| Several compression algorithms are available, which differ |
| in efficiency, compression and decompression speed. |
| Compression speed is only relevant when building a kernel. |
| Decompression speed is relevant at each boot. |
| |
| If you have any problems with bzip2 or lzma compressed |
| kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older |
| version of this functionality (bzip2 only), for 2.4, was |
| supplied by Christian Ludwig) |
| |
| High compression options are mostly useful for users, who |
| are low on disk space (embedded systems), but for whom ram |
| size matters less. |
| |
| If in doubt, select 'gzip' |
| |
| config KERNEL_GZIP |
| bool "Gzip" |
| depends on HAVE_KERNEL_GZIP |
| help |
| The old and tried gzip compression. It provides a good balance |
| between compression ratio and decompression speed. |
| |
| config KERNEL_BZIP2 |
| bool "Bzip2" |
| depends on HAVE_KERNEL_BZIP2 |
| help |
| Its compression ratio and speed is intermediate. |
| Decompression speed is slowest among the three. The kernel |
| size is about 10% smaller with bzip2, in comparison to gzip. |
| Bzip2 uses a large amount of memory. For modern kernels you |
| will need at least 8MB RAM or more for booting. |
| |
| config KERNEL_LZMA |
| bool "LZMA" |
| depends on HAVE_KERNEL_LZMA |
| help |
| The most recent compression algorithm. |
| Its ratio is best, decompression speed is between the other |
| two. Compression is slowest. The kernel size is about 33% |
| smaller with LZMA in comparison to gzip. |
| |
| config KERNEL_LZO |
| bool "LZO" |
| depends on HAVE_KERNEL_LZO |
| help |
| Its compression ratio is the poorest among the 4. The kernel |
| size is about about 10% bigger than gzip; however its speed |
| (both compression and decompression) is the fastest. |
| |
| endchoice |
| |
| config SWAP |
| bool "Support for paging of anonymous memory (swap)" |
| depends on MMU && BLOCK |
| default y |
| help |
| This option allows you to choose whether you want to have support |
| for so called swap devices or swap files in your kernel that are |
| used to provide more virtual memory than the actual RAM present |
| in your computer. If unsure say Y. |
| |
| config SYSVIPC |
| bool "System V IPC" |
| ---help--- |
| Inter Process Communication is a suite of library functions and |
| system calls which let processes (running programs) synchronize and |
| exchange information. It is generally considered to be a good thing, |
| and some programs won't run unless you say Y here. In particular, if |
| you want to run the DOS emulator dosemu under Linux (read the |
| DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), |
| you'll need to say Y here. |
| |
| You can find documentation about IPC with "info ipc" and also in |
| section 6.4 of the Linux Programmer's Guide, available from |
| <http://www.tldp.org/guides.html>. |
| |
| config SYSVIPC_SYSCTL |
| bool |
| depends on SYSVIPC |
| depends on SYSCTL |
| default y |
| |
| config POSIX_MQUEUE |
| bool "POSIX Message Queues" |
| depends on NET && EXPERIMENTAL |
| ---help--- |
| POSIX variant of message queues is a part of IPC. In POSIX message |
| queues every message has a priority which decides about succession |
| of receiving it by a process. If you want to compile and run |
| programs written e.g. for Solaris with use of its POSIX message |
| queues (functions mq_*) say Y here. |
| |
| POSIX message queues are visible as a filesystem called 'mqueue' |
| and can be mounted somewhere if you want to do filesystem |
| operations on message queues. |
| |
| If unsure, say Y. |
| |
| config POSIX_MQUEUE_SYSCTL |
| bool |
| depends on POSIX_MQUEUE |
| depends on SYSCTL |
| default y |
| |
| config BSD_PROCESS_ACCT |
| bool "BSD Process Accounting" |
| help |
| If you say Y here, a user level program will be able to instruct the |
| kernel (via a special system call) to write process accounting |
| information to a file: whenever a process exits, information about |
| that process will be appended to the file by the kernel. The |
| information includes things such as creation time, owning user, |
| command name, memory usage, controlling terminal etc. (the complete |
| list is in the struct acct in <file:include/linux/acct.h>). It is |
| up to the user level program to do useful things with this |
| information. This is generally a good idea, so say Y. |
| |
| config BSD_PROCESS_ACCT_V3 |
| bool "BSD Process Accounting version 3 file format" |
| depends on BSD_PROCESS_ACCT |
| default n |
| help |
| If you say Y here, the process accounting information is written |
| in a new file format that also logs the process IDs of each |
| process and it's parent. Note that this file format is incompatible |
| with previous v0/v1/v2 file formats, so you will need updated tools |
| for processing it. A preliminary version of these tools is available |
| at <http://www.gnu.org/software/acct/>. |
| |
| config TASKSTATS |
| bool "Export task/process statistics through netlink (EXPERIMENTAL)" |
| depends on NET |
| default n |
| help |
| Export selected statistics for tasks/processes through the |
| generic netlink interface. Unlike BSD process accounting, the |
| statistics are available during the lifetime of tasks/processes as |
| responses to commands. Like BSD accounting, they are sent to user |
| space on task exit. |
| |
| Say N if unsure. |
| |
| config TASK_DELAY_ACCT |
| bool "Enable per-task delay accounting (EXPERIMENTAL)" |
| depends on TASKSTATS |
| help |
| Collect information on time spent by a task waiting for system |
| resources like cpu, synchronous block I/O completion and swapping |
| in pages. Such statistics can help in setting a task's priorities |
| relative to other tasks for cpu, io, rss limits etc. |
| |
| Say N if unsure. |
| |
| config TASK_XACCT |
| bool "Enable extended accounting over taskstats (EXPERIMENTAL)" |
| depends on TASKSTATS |
| help |
| Collect extended task accounting data and send the data |
| to userland for processing over the taskstats interface. |
| |
| Say N if unsure. |
| |
| config TASK_IO_ACCOUNTING |
| bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" |
| depends on TASK_XACCT |
| help |
| Collect information on the number of bytes of storage I/O which this |
| task has caused. |
| |
| Say N if unsure. |
| |
| config AUDIT |
| bool "Auditing support" |
| depends on NET |
| help |
| Enable auditing infrastructure that can be used with another |
| kernel subsystem, such as SELinux (which requires this for |
| logging of avc messages output). Does not do system-call |
| auditing without CONFIG_AUDITSYSCALL. |
| |
| config AUDITSYSCALL |
| bool "Enable system-call auditing support" |
| depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH) |
| default y if SECURITY_SELINUX |
| help |
| Enable low-overhead system-call auditing infrastructure that |
| can be used independently or with another kernel subsystem, |
| such as SELinux. To use audit's filesystem watch feature, please |
| ensure that INOTIFY is configured. |
| |
| config AUDIT_TREE |
| def_bool y |
| depends on AUDITSYSCALL |
| select INOTIFY |
| |
| menu "RCU Subsystem" |
| |
| choice |
| prompt "RCU Implementation" |
| default TREE_RCU |
| |
| config TREE_RCU |
| bool "Tree-based hierarchical RCU" |
| help |
| This option selects the RCU implementation that is |
| designed for very large SMP system with hundreds or |
| thousands of CPUs. It also scales down nicely to |
| smaller systems. |
| |
| config TREE_PREEMPT_RCU |
| bool "Preemptable tree-based hierarchical RCU" |
| depends on PREEMPT |
| help |
| This option selects the RCU implementation that is |
| designed for very large SMP systems with hundreds or |
| thousands of CPUs, but for which real-time response |
| is also required. It also scales down nicely to |
| smaller systems. |
| |
| config TINY_RCU |
| bool "UP-only small-memory-footprint RCU" |
| depends on !SMP |
| help |
| This option selects the RCU implementation that is |
| designed for UP systems from which real-time response |
| is not required. This option greatly reduces the |
| memory footprint of RCU. |
| |
| endchoice |
| |
| config RCU_TRACE |
| bool "Enable tracing for RCU" |
| depends on TREE_RCU || TREE_PREEMPT_RCU |
| help |
| This option provides tracing in RCU which presents stats |
| in debugfs for debugging RCU implementation. |
| |
| Say Y here if you want to enable RCU tracing |
| Say N if you are unsure. |
| |
| config RCU_FANOUT |
| int "Tree-based hierarchical RCU fanout value" |
| range 2 64 if 64BIT |
| range 2 32 if !64BIT |
| depends on TREE_RCU || TREE_PREEMPT_RCU |
| default 64 if 64BIT |
| default 32 if !64BIT |
| help |
| This option controls the fanout of hierarchical implementations |
| of RCU, allowing RCU to work efficiently on machines with |
| large numbers of CPUs. This value must be at least the cube |
| root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit |
| systems and up to 262,144 for 64-bit systems. |
| |
| Select a specific number if testing RCU itself. |
| Take the default if unsure. |
| |
| config RCU_FANOUT_EXACT |
| bool "Disable tree-based hierarchical RCU auto-balancing" |
| depends on TREE_RCU || TREE_PREEMPT_RCU |
| default n |
| help |
| This option forces use of the exact RCU_FANOUT value specified, |
| regardless of imbalances in the hierarchy. This is useful for |
| testing RCU itself, and might one day be useful on systems with |
| strong NUMA behavior. |
| |
| Without RCU_FANOUT_EXACT, the code will balance the hierarchy. |
| |
| Say N if unsure. |
| |
| config RCU_FAST_NO_HZ |
| bool "Accelerate last non-dyntick-idle CPU's grace periods" |
| depends on TREE_RCU && NO_HZ && SMP |
| default n |
| help |
| This option causes RCU to attempt to accelerate grace periods |
| in order to allow the final CPU 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. |
| |
| endmenu # "RCU Subsystem" |
| |
| config IKCONFIG |
| tristate "Kernel .config support" |
| ---help--- |
| This option enables the complete Linux kernel ".config" file |
| contents to be saved in the kernel. It provides documentation |
| of which kernel options are used in a running kernel or in an |
| on-disk kernel. This information can be extracted from the kernel |
| image file with the script scripts/extract-ikconfig and used as |
| input to rebuild the current kernel or to build another kernel. |
| It can also be extracted from a running kernel by reading |
| /proc/config.gz if enabled (below). |
| |
| config IKCONFIG_PROC |
| bool "Enable access to .config through /proc/config.gz" |
| depends on IKCONFIG && PROC_FS |
| ---help--- |
| This option enables access to the kernel configuration file |
| through /proc/config.gz. |
| |
| config LOG_BUF_SHIFT |
| int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" |
| range 12 21 |
| default 17 |
| help |
| Select kernel log buffer size as a power of 2. |
| Examples: |
| 17 => 128 KB |
| 16 => 64 KB |
| 15 => 32 KB |
| 14 => 16 KB |
| 13 => 8 KB |
| 12 => 4 KB |
| |
| # |
| # Architectures with an unreliable sched_clock() should select this: |
| # |
| config HAVE_UNSTABLE_SCHED_CLOCK |
| bool |
| |
| config GROUP_SCHED |
| bool "Group CPU scheduler" |
| depends on EXPERIMENTAL |
| default n |
| help |
| This feature lets CPU scheduler recognize task groups and control CPU |
| bandwidth allocation to such task groups. |
| In order to create a group from arbitrary set of processes, use |
| CONFIG_CGROUPS. (See Control Group support.) |
| |
| config FAIR_GROUP_SCHED |
| bool "Group scheduling for SCHED_OTHER" |
| depends on GROUP_SCHED |
| default GROUP_SCHED |
| |
| config RT_GROUP_SCHED |
| bool "Group scheduling for SCHED_RR/FIFO" |
| depends on EXPERIMENTAL |
| depends on GROUP_SCHED |
| default n |
| help |
| This feature lets you explicitly allocate real CPU bandwidth |
| to users or control groups (depending on the "Basis for grouping tasks" |
| setting below. 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. |
| |
| choice |
| depends on GROUP_SCHED |
| prompt "Basis for grouping tasks" |
| default USER_SCHED |
| |
| config USER_SCHED |
| bool "user id" |
| help |
| This option will choose userid as the basis for grouping |
| tasks, thus providing equal CPU bandwidth to each user. |
| |
| config CGROUP_SCHED |
| bool "Control groups" |
| depends on CGROUPS |
| help |
| This option allows you to create arbitrary task groups |
| using the "cgroup" pseudo filesystem and control |
| the cpu bandwidth allocated to each such task group. |
| Refer to Documentation/cgroups/cgroups.txt for more |
| information on "cgroup" pseudo filesystem. |
| |
| endchoice |
| |
| menuconfig CGROUPS |
| boolean "Control Group support" |
| 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" |
| depends on CGROUPS |
| 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_NS |
| bool "Namespace cgroup subsystem" |
| depends on CGROUPS |
| help |
| Provides a simple namespace cgroup subsystem to |
| provide hierarchical naming of sets of namespaces, |
| for instance virtual servers and checkpoint/restart |
| jobs. |
| |
| config CGROUP_FREEZER |
| bool "Freezer cgroup subsystem" |
| depends on CGROUPS |
| help |
| Provides a way to freeze and unfreeze all tasks in a |
| cgroup. |
| |
| config CGROUP_DEVICE |
| bool "Device controller for cgroups" |
| depends on CGROUPS && EXPERIMENTAL |
| help |
| Provides a cgroup implementing whitelists for devices which |
| a process in the cgroup can mknod or open. |
| |
| config CPUSETS |
| bool "Cpuset support" |
| depends on CGROUPS |
| 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" |
| depends on CGROUPS |
| 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. |
| depends on CGROUPS |
| |
| config CGROUP_MEM_RES_CTLR |
| bool "Memory Resource Controller for Control Groups" |
| depends on CGROUPS && RESOURCE_COUNTERS |
| select MM_OWNER |
| help |
| Provides a memory resource controller that manages both anonymous |
| memory and page cache. (See Documentation/cgroups/memory.txt) |
| |
| Note that setting this option increases fixed memory overhead |
| associated with each page of memory in the system. By this, |
| 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory |
| usage tracking struct at boot. Total amount of this is printed out |
| at boot. |
| |
| Only enable when you're ok with these trade offs and really |
| sure you need the memory resource controller. Even when you enable |
| this, you can set "cgroup_disable=memory" at your boot option to |
| disable memory resource controller and you can avoid overheads. |
| (and lose benefits of memory resource controller) |
| |
| This config option also selects MM_OWNER config option, which |
| could in turn add some fork/exit overhead. |
| |
| config CGROUP_MEM_RES_CTLR_SWAP |
| bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)" |
| depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL |
| 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 "noswapaccount" 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. |
| |
| endif # CGROUPS |
| |
| config MM_OWNER |
| bool |
| |
| config SYSFS_DEPRECATED |
| bool |
| |
| config SYSFS_DEPRECATED_V2 |
| bool "enable deprecated sysfs features to support old userspace tools" |
| depends on SYSFS |
| default n |
| select SYSFS_DEPRECATED |
| help |
| This option switches the layout of sysfs to the deprecated |
| version. Do not use it on recent distributions. |
| |
| The current sysfs layout features a unified device tree at |
| /sys/devices/, which is able to express a hierarchy between |
| class devices. If the deprecated option is set to Y, the |
| unified device tree is split into a bus device tree at |
| /sys/devices/ and several individual class device trees at |
| /sys/class/. The class and bus devices will be connected by |
| "<subsystem>:<name>" and the "device" links. The "block" |
| class devices, will not show up in /sys/class/block/. Some |
| subsystems will suppress the creation of some devices which |
| depend on the unified device tree. |
| |
| This option is not a pure compatibility option that can |
| be safely enabled on newer distributions. It will change the |
| layout of sysfs to the non-extensible deprecated version, |
| and disable some features, which can not be exported without |
| confusing older userspace tools. Since 2007/2008 all major |
| distributions do not enable this option, and ship no tools which |
| depend on the deprecated layout or this option. |
| |
| If you are using a new kernel on an older distribution, or use |
| older userspace tools, you might need to say Y here. Do not say Y, |
| if the original kernel, that came with your distribution, has |
| this option set to N. |
| |
| 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 NAMESPACES |
| bool "Namespaces support" if EMBEDDED |
| default !EMBEDDED |
| 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. |
| |
| config UTS_NS |
| bool "UTS namespace" |
| depends on NAMESPACES |
| help |
| In this namespace tasks see different info provided with the |
| uname() system call |
| |
| config IPC_NS |
| bool "IPC namespace" |
| depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE) |
| 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 NAMESPACES && EXPERIMENTAL |
| 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 (EXPERIMENTAL)" |
| default n |
| depends on NAMESPACES && EXPERIMENTAL |
| 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. |
| |
| Unless you want to work with an experimental feature |
| say N here. |
| |
| config NET_NS |
| bool "Network namespace" |
| default n |
| depends on NAMESPACES && EXPERIMENTAL && NET |
| help |
| Allow user space to create what appear to be multiple instances |
| of the network stack. |
| |
| 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" |
| default y |
| 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 EMBEDDED |
| bool "Configure standard kernel features (for small systems)" |
| 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 EMBEDDED |
| 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 EMBEDDED |
| depends on PROC_SYSCTL |
| default y |
| 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 Y here. |
| |
| config KALLSYMS |
| bool "Load all symbols for debugging/ksymoops" if EMBEDDED |
| 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. Some debuggers can use kallsyms for other |
| symbols too: say Y here to include all symbols, if you need them |
| and you don't care about adding 300k to the size of your kernel. |
| |
| Say N. |
| |
| config KALLSYMS_EXTRA_PASS |
| bool "Do an extra kallsyms pass" |
| depends on KALLSYMS |
| help |
| If kallsyms is not working correctly, the build will fail with |
| inconsistent kallsyms data. If that occurs, log a bug report and |
| turn on KALLSYMS_EXTRA_PASS which should result in a stable build. |
| Always say N here unless you find a bug in kallsyms, which must be |
| reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while |
| you wait for kallsyms to be fixed. |
| |
| |
| config HOTPLUG |
| bool "Support for hot-pluggable devices" if EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| help |
| Enable support for generating core dumps. Disabling saves about 4k. |
| |
| config PCSPKR_PLATFORM |
| bool "Enable PC-Speaker support" if EMBEDDED |
| depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES |
| default y |
| help |
| This option allows to disable the internal PC-Speaker |
| support, saving some memory. |
| |
| config BASE_FULL |
| default y |
| bool "Enable full-sized data structures for core" if EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 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 || PERF_COUNTERS) |
| depends on HAVE_PERF_EVENTS |
| select ANON_INODES |
| 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 EVENT_PROFILE |
| bool "Tracepoint profiling sources" |
| depends on PERF_EVENTS && EVENT_TRACING |
| default y |
| help |
| Allow the use of tracepoints as software performance events. |
| |
| When this is enabled, you can create perf events based on |
| tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID |
| found in debugfs://tracing/events/*/*/id. (The -e/--events |
| option to the perf tool can parse and interpret symbolic |
| tracepoints, in the subsystem:tracepoint_name format.) |
| |
| config PERF_COUNTERS |
| bool "Kernel performance counters (old config option)" |
| depends on HAVE_PERF_EVENTS |
| help |
| This config has been obsoleted by the PERF_EVENTS |
| config option - please see that one for details. |
| |
| It has no effect on the kernel whether you enable |
| it or not, it is a compatibility placeholder. |
| |
| Say N 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 EMBEDDED |
| help |
| VM event counters are needed for event counts to be shown. |
| This option allows the disabling of the VM event counters |
| on EMBEDDED 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED |
| 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 EMBEDDED && !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 (EXPERIMENTAL)" |
| 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" |
| |
| config SLOW_WORK |
| default n |
| bool |
| help |
| The slow work thread pool provides a number of dynamically allocated |
| threads that can be used by the kernel to perform operations that |
| take a relatively long time. |
| |
| An example of this would be CacheFiles doing a path lookup followed |
| by a series of mkdirs and a create call, all of which have to touch |
| disk. |
| |
| See Documentation/slow-work.txt. |
| |
| config SLOW_WORK_DEBUG |
| bool "Slow work debugging through debugfs" |
| default n |
| depends on SLOW_WORK && DEBUG_FS |
| help |
| Display the contents of the slow work run queue through debugfs, |
| including items currently executing. |
| |
| See Documentation/slow-work.txt. |
| |
| 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_map and |
| cpu_possible_map, some of them chose to initialize cpu_possible_map |
| 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" |