|  | config ARCH | 
|  | string | 
|  | option env="ARCH" | 
|  |  | 
|  | config KERNELVERSION | 
|  | string | 
|  | option env="KERNELVERSION" | 
|  |  | 
|  | config DEFCONFIG_LIST | 
|  | string | 
|  | depends on !UML | 
|  | option defconfig_list | 
|  | default "/lib/modules/$UNAME_RELEASE/.config" | 
|  | default "/etc/kernel-config" | 
|  | default "/boot/config-$UNAME_RELEASE" | 
|  | default "$ARCH_DEFCONFIG" | 
|  | default "arch/$ARCH/defconfig" | 
|  |  | 
|  | config CONSTRUCTORS | 
|  | bool | 
|  | depends on !UML | 
|  |  | 
|  | config HAVE_IRQ_WORK | 
|  | bool | 
|  |  | 
|  | config IRQ_WORK | 
|  | bool | 
|  | depends on HAVE_IRQ_WORK | 
|  |  | 
|  | menu "General setup" | 
|  |  | 
|  | config EXPERIMENTAL | 
|  | bool "Prompt for development and/or incomplete code/drivers" | 
|  | ---help--- | 
|  | Some of the various things that Linux supports (such as network | 
|  | drivers, file systems, network protocols, etc.) can be in a state | 
|  | of development where the functionality, stability, or the level of | 
|  | testing is not yet high enough for general use. This is usually | 
|  | known as the "alpha-test" phase among developers. If a feature is | 
|  | currently in alpha-test, then the developers usually discourage | 
|  | uninformed widespread use of this feature by the general public to | 
|  | avoid "Why doesn't this work?" type mail messages. However, active | 
|  | testing and use of these systems is welcomed. Just be aware that it | 
|  | may not meet the normal level of reliability or it may fail to work | 
|  | in some special cases. Detailed bug reports from people familiar | 
|  | with the kernel internals are usually welcomed by the developers | 
|  | (before submitting bug reports, please read the documents | 
|  | <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, | 
|  | <file:Documentation/BUG-HUNTING>, and | 
|  | <file:Documentation/oops-tracing.txt> in the kernel source). | 
|  |  | 
|  | This option will also make obsoleted drivers available. These are | 
|  | drivers that have been replaced by something else, and/or are | 
|  | scheduled to be removed in a future kernel release. | 
|  |  | 
|  | Unless you intend to help test and develop a feature or driver that | 
|  | falls into this category, or you have a situation that requires | 
|  | using these features, you should probably say N here, which will | 
|  | cause the configurator to present you with fewer choices. If | 
|  | you say Y here, you will be offered the choice of using features or | 
|  | drivers that are currently considered to be in the alpha-test phase. | 
|  |  | 
|  | config BROKEN | 
|  | bool | 
|  |  | 
|  | config BROKEN_ON_SMP | 
|  | bool | 
|  | depends on BROKEN || !SMP | 
|  | default y | 
|  |  | 
|  | config INIT_ENV_ARG_LIMIT | 
|  | int | 
|  | default 32 if !UML | 
|  | default 128 if UML | 
|  | help | 
|  | Maximum of each of the number of arguments and environment | 
|  | variables passed to init from the kernel command line. | 
|  |  | 
|  |  | 
|  | config CROSS_COMPILE | 
|  | string "Cross-compiler tool prefix" | 
|  | help | 
|  | Same as running 'make CROSS_COMPILE=prefix-' but stored for | 
|  | default make runs in this kernel build directory.  You don't | 
|  | need to set this unless you want the configured kernel build | 
|  | directory to select the cross-compiler automatically. | 
|  |  | 
|  | config LOCALVERSION | 
|  | string "Local version - append to kernel release" | 
|  | help | 
|  | Append an extra string to the end of your kernel version. | 
|  | This will show up when you type uname, for example. | 
|  | The string you set here will be appended after the contents of | 
|  | any files with a filename matching localversion* in your | 
|  | object and source tree, in that order.  Your total string can | 
|  | be a maximum of 64 characters. | 
|  |  | 
|  | config LOCALVERSION_AUTO | 
|  | bool "Automatically append version information to the version string" | 
|  | default y | 
|  | help | 
|  | This will try to automatically determine if the current tree is a | 
|  | release tree by looking for git tags that belong to the current | 
|  | top of tree revision. | 
|  |  | 
|  | A string of the format -gxxxxxxxx will be added to the localversion | 
|  | if a git-based tree is found.  The string generated by this will be | 
|  | appended after any matching localversion* files, and after the value | 
|  | set in CONFIG_LOCALVERSION. | 
|  |  | 
|  | (The actual string used here is the first eight characters produced | 
|  | by running the command: | 
|  |  | 
|  | $ git rev-parse --verify HEAD | 
|  |  | 
|  | which is done within the script "scripts/setlocalversion".) | 
|  |  | 
|  | config HAVE_KERNEL_GZIP | 
|  | bool | 
|  |  | 
|  | config HAVE_KERNEL_BZIP2 | 
|  | bool | 
|  |  | 
|  | config HAVE_KERNEL_LZMA | 
|  | bool | 
|  |  | 
|  | config HAVE_KERNEL_XZ | 
|  | bool | 
|  |  | 
|  | config HAVE_KERNEL_LZO | 
|  | bool | 
|  |  | 
|  | choice | 
|  | prompt "Kernel compression mode" | 
|  | default KERNEL_GZIP | 
|  | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO | 
|  | help | 
|  | The linux kernel is a kind of self-extracting executable. | 
|  | Several compression algorithms are available, which differ | 
|  | in efficiency, compression and decompression speed. | 
|  | Compression speed is only relevant when building a kernel. | 
|  | Decompression speed is relevant at each boot. | 
|  |  | 
|  | If you have any problems with bzip2 or lzma compressed | 
|  | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older | 
|  | version of this functionality (bzip2 only), for 2.4, was | 
|  | supplied by Christian Ludwig) | 
|  |  | 
|  | High compression options are mostly useful for users, who | 
|  | are low on disk space (embedded systems), but for whom ram | 
|  | size matters less. | 
|  |  | 
|  | If in doubt, select 'gzip' | 
|  |  | 
|  | config KERNEL_GZIP | 
|  | bool "Gzip" | 
|  | depends on HAVE_KERNEL_GZIP | 
|  | help | 
|  | The old and tried gzip compression. It provides a good balance | 
|  | between compression ratio and decompression speed. | 
|  |  | 
|  | config KERNEL_BZIP2 | 
|  | bool "Bzip2" | 
|  | depends on HAVE_KERNEL_BZIP2 | 
|  | help | 
|  | Its compression ratio and speed is intermediate. | 
|  | Decompression speed is slowest among the three.  The kernel | 
|  | size is about 10% smaller with bzip2, in comparison to gzip. | 
|  | Bzip2 uses a large amount of memory. For modern kernels you | 
|  | will need at least 8MB RAM or more for booting. | 
|  |  | 
|  | config KERNEL_LZMA | 
|  | bool "LZMA" | 
|  | depends on HAVE_KERNEL_LZMA | 
|  | help | 
|  | The most recent compression algorithm. | 
|  | Its ratio is best, decompression speed is between the other | 
|  | two. Compression is slowest.	The kernel size is about 33% | 
|  | smaller with LZMA in comparison to gzip. | 
|  |  | 
|  | config KERNEL_XZ | 
|  | bool "XZ" | 
|  | depends on HAVE_KERNEL_XZ | 
|  | help | 
|  | XZ uses the LZMA2 algorithm and instruction set specific | 
|  | BCJ filters which can improve compression ratio of executable | 
|  | code. The size of the kernel is about 30% smaller with XZ in | 
|  | comparison to gzip. On architectures for which there is a BCJ | 
|  | filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ | 
|  | will create a few percent smaller kernel than plain LZMA. | 
|  |  | 
|  | The speed is about the same as with LZMA: The decompression | 
|  | speed of XZ is better than that of bzip2 but worse than gzip | 
|  | and LZO. Compression is slow. | 
|  |  | 
|  | config KERNEL_LZO | 
|  | bool "LZO" | 
|  | depends on HAVE_KERNEL_LZO | 
|  | help | 
|  | Its compression ratio is the poorest among the 4. The kernel | 
|  | size is about 10% bigger than gzip; however its speed | 
|  | (both compression and decompression) is the fastest. | 
|  |  | 
|  | endchoice | 
|  |  | 
|  | config DEFAULT_HOSTNAME | 
|  | string "Default hostname" | 
|  | default "(none)" | 
|  | help | 
|  | This option determines the default system hostname before userspace | 
|  | calls sethostname(2). The kernel traditionally uses "(none)" here, | 
|  | but you may wish to use a different default here to make a minimal | 
|  | system more usable with less configuration. | 
|  |  | 
|  | config SWAP | 
|  | bool "Support for paging of anonymous memory (swap)" | 
|  | depends on MMU && BLOCK | 
|  | default y | 
|  | help | 
|  | This option allows you to choose whether you want to have support | 
|  | for so called swap devices or swap files in your kernel that are | 
|  | used to provide more virtual memory than the actual RAM present | 
|  | in your computer.  If unsure say Y. | 
|  |  | 
|  | config SYSVIPC | 
|  | bool "System V IPC" | 
|  | ---help--- | 
|  | Inter Process Communication is a suite of library functions and | 
|  | system calls which let processes (running programs) synchronize and | 
|  | exchange information. It is generally considered to be a good thing, | 
|  | and some programs won't run unless you say Y here. In particular, if | 
|  | you want to run the DOS emulator dosemu under Linux (read the | 
|  | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), | 
|  | you'll need to say Y here. | 
|  |  | 
|  | You can find documentation about IPC with "info ipc" and also in | 
|  | section 6.4 of the Linux Programmer's Guide, available from | 
|  | <http://www.tldp.org/guides.html>. | 
|  |  | 
|  | config SYSVIPC_SYSCTL | 
|  | bool | 
|  | depends on SYSVIPC | 
|  | depends on SYSCTL | 
|  | default y | 
|  |  | 
|  | config POSIX_MQUEUE | 
|  | bool "POSIX Message Queues" | 
|  | depends on NET && EXPERIMENTAL | 
|  | ---help--- | 
|  | POSIX variant of message queues is a part of IPC. In POSIX message | 
|  | queues every message has a priority which decides about succession | 
|  | of receiving it by a process. If you want to compile and run | 
|  | programs written e.g. for Solaris with use of its POSIX message | 
|  | queues (functions mq_*) say Y here. | 
|  |  | 
|  | POSIX message queues are visible as a filesystem called 'mqueue' | 
|  | and can be mounted somewhere if you want to do filesystem | 
|  | operations on message queues. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config POSIX_MQUEUE_SYSCTL | 
|  | bool | 
|  | depends on POSIX_MQUEUE | 
|  | depends on SYSCTL | 
|  | default y | 
|  |  | 
|  | config BSD_PROCESS_ACCT | 
|  | bool "BSD Process Accounting" | 
|  | help | 
|  | If you say Y here, a user level program will be able to instruct the | 
|  | kernel (via a special system call) to write process accounting | 
|  | information to a file: whenever a process exits, information about | 
|  | that process will be appended to the file by the kernel.  The | 
|  | information includes things such as creation time, owning user, | 
|  | command name, memory usage, controlling terminal etc. (the complete | 
|  | list is in the struct acct in <file:include/linux/acct.h>).  It is | 
|  | up to the user level program to do useful things with this | 
|  | information.  This is generally a good idea, so say Y. | 
|  |  | 
|  | config BSD_PROCESS_ACCT_V3 | 
|  | bool "BSD Process Accounting version 3 file format" | 
|  | depends on BSD_PROCESS_ACCT | 
|  | default n | 
|  | help | 
|  | If you say Y here, the process accounting information is written | 
|  | in a new file format that also logs the process IDs of each | 
|  | process and it's parent. Note that this file format is incompatible | 
|  | with previous v0/v1/v2 file formats, so you will need updated tools | 
|  | for processing it. A preliminary version of these tools is available | 
|  | at <http://www.gnu.org/software/acct/>. | 
|  |  | 
|  | config FHANDLE | 
|  | bool "open by fhandle syscalls" | 
|  | select EXPORTFS | 
|  | help | 
|  | If you say Y here, a user level program will be able to map | 
|  | file names to handle and then later use the handle for | 
|  | different file system operations. This is useful in implementing | 
|  | userspace file servers, which now track files using handles instead | 
|  | of names. The handle would remain the same even if file names | 
|  | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) | 
|  | syscalls. | 
|  |  | 
|  | config TASKSTATS | 
|  | bool "Export task/process statistics through netlink (EXPERIMENTAL)" | 
|  | depends on NET | 
|  | default n | 
|  | help | 
|  | Export selected statistics for tasks/processes through the | 
|  | generic netlink interface. Unlike BSD process accounting, the | 
|  | statistics are available during the lifetime of tasks/processes as | 
|  | responses to commands. Like BSD accounting, they are sent to user | 
|  | space on task exit. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config TASK_DELAY_ACCT | 
|  | bool "Enable per-task delay accounting (EXPERIMENTAL)" | 
|  | depends on TASKSTATS | 
|  | help | 
|  | Collect information on time spent by a task waiting for system | 
|  | resources like cpu, synchronous block I/O completion and swapping | 
|  | in pages. Such statistics can help in setting a task's priorities | 
|  | relative to other tasks for cpu, io, rss limits etc. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config TASK_XACCT | 
|  | bool "Enable extended accounting over taskstats (EXPERIMENTAL)" | 
|  | depends on TASKSTATS | 
|  | help | 
|  | Collect extended task accounting data and send the data | 
|  | to userland for processing over the taskstats interface. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config TASK_IO_ACCOUNTING | 
|  | bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" | 
|  | depends on TASK_XACCT | 
|  | help | 
|  | Collect information on the number of bytes of storage I/O which this | 
|  | task has caused. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config AUDIT | 
|  | bool "Auditing support" | 
|  | depends on NET | 
|  | help | 
|  | Enable auditing infrastructure that can be used with another | 
|  | kernel subsystem, such as SELinux (which requires this for | 
|  | logging of avc messages output).  Does not do system-call | 
|  | auditing without CONFIG_AUDITSYSCALL. | 
|  |  | 
|  | config AUDITSYSCALL | 
|  | bool "Enable system-call auditing support" | 
|  | depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH) | 
|  | default y if SECURITY_SELINUX | 
|  | help | 
|  | Enable low-overhead system-call auditing infrastructure that | 
|  | can be used independently or with another kernel subsystem, | 
|  | such as SELinux. | 
|  |  | 
|  | config AUDIT_WATCH | 
|  | def_bool y | 
|  | depends on AUDITSYSCALL | 
|  | select FSNOTIFY | 
|  |  | 
|  | config AUDIT_TREE | 
|  | def_bool y | 
|  | depends on AUDITSYSCALL | 
|  | select FSNOTIFY | 
|  |  | 
|  | source "kernel/irq/Kconfig" | 
|  |  | 
|  | menu "RCU Subsystem" | 
|  |  | 
|  | choice | 
|  | prompt "RCU Implementation" | 
|  | default TREE_RCU | 
|  |  | 
|  | config TREE_RCU | 
|  | bool "Tree-based hierarchical RCU" | 
|  | depends on !PREEMPT && SMP | 
|  | help | 
|  | This option selects the RCU implementation that is | 
|  | designed for very large SMP system with hundreds or | 
|  | thousands of CPUs.  It also scales down nicely to | 
|  | smaller systems. | 
|  |  | 
|  | config TREE_PREEMPT_RCU | 
|  | bool "Preemptible tree-based hierarchical RCU" | 
|  | depends on PREEMPT | 
|  | 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. | 
|  |  | 
|  | config TINY_PREEMPT_RCU | 
|  | bool "Preemptible UP-only small-memory-footprint RCU" | 
|  | depends on !SMP && PREEMPT | 
|  | help | 
|  | This option selects the RCU implementation that is designed | 
|  | for real-time UP systems.  This option greatly reduces the | 
|  | memory footprint of RCU. | 
|  |  | 
|  | endchoice | 
|  |  | 
|  | config PREEMPT_RCU | 
|  | def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) | 
|  | help | 
|  | This option enables preemptible-RCU code that is common between | 
|  | the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. | 
|  |  | 
|  | config RCU_TRACE | 
|  | bool "Enable tracing for 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 fourth | 
|  | root of NR_CPUS, which allows NR_CPUS to be insanely large. | 
|  | The default value of RCU_FANOUT should be used for production | 
|  | systems, but if you are stress-testing the RCU implementation | 
|  | itself, small RCU_FANOUT values allow you to test large-system | 
|  | code paths on small(er) systems. | 
|  |  | 
|  | Select a specific number if testing RCU itself. | 
|  | Take the default if unsure. | 
|  |  | 
|  | config RCU_FANOUT_EXACT | 
|  | bool "Disable tree-based hierarchical RCU auto-balancing" | 
|  | depends on TREE_RCU || TREE_PREEMPT_RCU | 
|  | default n | 
|  | help | 
|  | This option forces use of the exact RCU_FANOUT value specified, | 
|  | regardless of imbalances in the hierarchy.  This is useful for | 
|  | testing RCU itself, and might one day be useful on systems with | 
|  | strong NUMA behavior. | 
|  |  | 
|  | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config RCU_FAST_NO_HZ | 
|  | bool "Accelerate last non-dyntick-idle CPU's grace periods" | 
|  | depends on 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. | 
|  |  | 
|  | config RCU_BOOST | 
|  | bool "Enable RCU priority boosting" | 
|  | depends on RT_MUTEXES && PREEMPT_RCU | 
|  | default n | 
|  | help | 
|  | This option boosts the priority of preempted RCU readers that | 
|  | block the current preemptible RCU grace period for too long. | 
|  | This option also prevents heavy loads from blocking RCU | 
|  | callback invocation for all flavors of RCU. | 
|  |  | 
|  | Say Y here if you are working with real-time apps or heavy loads | 
|  | Say N here if you are unsure. | 
|  |  | 
|  | config RCU_BOOST_PRIO | 
|  | int "Real-time priority to boost RCU readers to" | 
|  | range 1 99 | 
|  | depends on RCU_BOOST | 
|  | default 1 | 
|  | help | 
|  | This option specifies the real-time priority to which preempted | 
|  | RCU readers are to be boosted.  If you are working with CPU-bound | 
|  | real-time applications, you should specify a priority higher then | 
|  | the highest-priority CPU-bound application. | 
|  |  | 
|  | Specify the real-time priority, or take the default if unsure. | 
|  |  | 
|  | config RCU_BOOST_DELAY | 
|  | int "Milliseconds to delay boosting after RCU grace-period start" | 
|  | range 0 3000 | 
|  | depends on RCU_BOOST | 
|  | default 500 | 
|  | help | 
|  | This option specifies the time to wait after the beginning of | 
|  | a given grace period before priority-boosting preempted RCU | 
|  | readers blocking that grace period.  Note that any RCU reader | 
|  | blocking an expedited RCU grace period is boosted immediately. | 
|  |  | 
|  | Accept the default if unsure. | 
|  |  | 
|  | endmenu # "RCU Subsystem" | 
|  |  | 
|  | config IKCONFIG | 
|  | tristate "Kernel .config support" | 
|  | ---help--- | 
|  | This option enables the complete Linux kernel ".config" file | 
|  | contents to be saved in the kernel. It provides documentation | 
|  | of which kernel options are used in a running kernel or in an | 
|  | on-disk kernel.  This information can be extracted from the kernel | 
|  | image file with the script scripts/extract-ikconfig and used as | 
|  | input to rebuild the current kernel or to build another kernel. | 
|  | It can also be extracted from a running kernel by reading | 
|  | /proc/config.gz if enabled (below). | 
|  |  | 
|  | config IKCONFIG_PROC | 
|  | bool "Enable access to .config through /proc/config.gz" | 
|  | depends on IKCONFIG && PROC_FS | 
|  | ---help--- | 
|  | This option enables access to the kernel configuration file | 
|  | through /proc/config.gz. | 
|  |  | 
|  | config LOG_BUF_SHIFT | 
|  | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | 
|  | range 12 21 | 
|  | default 17 | 
|  | help | 
|  | Select kernel log buffer size as a power of 2. | 
|  | Examples: | 
|  | 17 => 128 KB | 
|  | 16 => 64 KB | 
|  | 15 => 32 KB | 
|  | 14 => 16 KB | 
|  | 13 =>  8 KB | 
|  | 12 =>  4 KB | 
|  |  | 
|  | # | 
|  | # Architectures with an unreliable sched_clock() should select this: | 
|  | # | 
|  | config HAVE_UNSTABLE_SCHED_CLOCK | 
|  | bool | 
|  |  | 
|  | menuconfig CGROUPS | 
|  | boolean "Control Group support" | 
|  | depends on EVENTFD | 
|  | help | 
|  | This option adds support for grouping sets of processes together, for | 
|  | use with process control subsystems such as Cpusets, CFS, memory | 
|  | controls or device isolation. | 
|  | See | 
|  | - Documentation/scheduler/sched-design-CFS.txt	(CFS) | 
|  | - Documentation/cgroups/ (features for grouping, isolation | 
|  | and resource control) | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | if CGROUPS | 
|  |  | 
|  | config CGROUP_DEBUG | 
|  | bool "Example debug cgroup subsystem" | 
|  | default n | 
|  | help | 
|  | This option enables a simple cgroup subsystem that | 
|  | exports useful debugging information about the cgroups | 
|  | framework. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config CGROUP_FREEZER | 
|  | bool "Freezer cgroup subsystem" | 
|  | help | 
|  | Provides a way to freeze and unfreeze all tasks in a | 
|  | cgroup. | 
|  |  | 
|  | config CGROUP_DEVICE | 
|  | bool "Device controller for cgroups" | 
|  | help | 
|  | Provides a cgroup implementing whitelists for devices which | 
|  | a process in the cgroup can mknod or open. | 
|  |  | 
|  | config CPUSETS | 
|  | bool "Cpuset support" | 
|  | help | 
|  | This option will let you create and manage CPUSETs which | 
|  | allow dynamically partitioning a system into sets of CPUs and | 
|  | Memory Nodes and assigning tasks to run only within those sets. | 
|  | This is primarily useful on large SMP or NUMA systems. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config PROC_PID_CPUSET | 
|  | bool "Include legacy /proc/<pid>/cpuset file" | 
|  | depends on CPUSETS | 
|  | default y | 
|  |  | 
|  | config CGROUP_CPUACCT | 
|  | bool "Simple CPU accounting cgroup subsystem" | 
|  | help | 
|  | Provides a simple Resource Controller for monitoring the | 
|  | total CPU consumed by the tasks in a cgroup. | 
|  |  | 
|  | config RESOURCE_COUNTERS | 
|  | bool "Resource counters" | 
|  | help | 
|  | This option enables controller independent resource accounting | 
|  | infrastructure that works with cgroups. | 
|  |  | 
|  | config CGROUP_MEM_RES_CTLR | 
|  | bool "Memory Resource Controller for Control Groups" | 
|  | depends on RESOURCE_COUNTERS | 
|  | select MM_OWNER | 
|  | help | 
|  | Provides a memory resource controller that manages both anonymous | 
|  | memory and page cache. (See Documentation/cgroups/memory.txt) | 
|  |  | 
|  | Note that setting this option increases fixed memory overhead | 
|  | associated with each page of memory in the system. By this, | 
|  | 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory | 
|  | usage tracking struct at boot. Total amount of this is printed out | 
|  | at boot. | 
|  |  | 
|  | Only enable when you're ok with these trade offs and really | 
|  | sure you need the memory resource controller. Even when you enable | 
|  | this, you can set "cgroup_disable=memory" at your boot option to | 
|  | disable memory resource controller and you can avoid overheads. | 
|  | (and lose benefits of memory resource controller) | 
|  |  | 
|  | This config option also selects MM_OWNER config option, which | 
|  | could in turn add some fork/exit overhead. | 
|  |  | 
|  | config CGROUP_MEM_RES_CTLR_SWAP | 
|  | bool "Memory Resource Controller Swap Extension" | 
|  | depends on CGROUP_MEM_RES_CTLR && SWAP | 
|  | help | 
|  | Add swap management feature to memory resource controller. When you | 
|  | enable this, you can limit mem+swap usage per cgroup. In other words, | 
|  | when you disable this, memory resource controller has no cares to | 
|  | usage of swap...a process can exhaust all of the swap. This extension | 
|  | is useful when you want to avoid exhaustion swap but this itself | 
|  | adds more overheads and consumes memory for remembering information. | 
|  | Especially if you use 32bit system or small memory system, please | 
|  | be careful about enabling this. When memory resource controller | 
|  | is disabled by boot option, this will be automatically disabled and | 
|  | there will be no overhead from this. Even when you set this config=y, | 
|  | if boot option "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. | 
|  | config CGROUP_MEM_RES_CTLR_SWAP_ENABLED | 
|  | bool "Memory Resource Controller Swap Extension enabled by default" | 
|  | depends on CGROUP_MEM_RES_CTLR_SWAP | 
|  | default y | 
|  | help | 
|  | Memory Resource Controller Swap Extension comes with its price in | 
|  | a bigger memory consumption. General purpose distribution kernels | 
|  | which want to enable the feature but keep it disabled by default | 
|  | and let the user enable it by swapaccount boot command line | 
|  | parameter should have this option unselected. | 
|  | For those who want to have the feature enabled by default should | 
|  | select this option (if, for some reason, they need to disable it | 
|  | then noswapaccount does the trick). | 
|  |  | 
|  | config CGROUP_PERF | 
|  | bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" | 
|  | depends on PERF_EVENTS && CGROUPS | 
|  | help | 
|  | This option extends the per-cpu mode to restrict monitoring to | 
|  | threads which belong to the cgroup specified and run on the | 
|  | designated cpu. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | menuconfig CGROUP_SCHED | 
|  | bool "Group CPU scheduler" | 
|  | depends on EXPERIMENTAL | 
|  | default n | 
|  | help | 
|  | This feature lets CPU scheduler recognize task groups and control CPU | 
|  | bandwidth allocation to such task groups. It uses cgroups to group | 
|  | tasks. | 
|  |  | 
|  | if CGROUP_SCHED | 
|  | config FAIR_GROUP_SCHED | 
|  | bool "Group scheduling for SCHED_OTHER" | 
|  | depends on CGROUP_SCHED | 
|  | default CGROUP_SCHED | 
|  |  | 
|  | config RT_GROUP_SCHED | 
|  | bool "Group scheduling for SCHED_RR/FIFO" | 
|  | depends on EXPERIMENTAL | 
|  | depends on CGROUP_SCHED | 
|  | default n | 
|  | help | 
|  | This feature lets you explicitly allocate real CPU bandwidth | 
|  | to task groups. If enabled, it will also make it impossible to | 
|  | schedule realtime tasks for non-root users until you allocate | 
|  | realtime bandwidth for them. | 
|  | See Documentation/scheduler/sched-rt-group.txt for more information. | 
|  |  | 
|  | endif #CGROUP_SCHED | 
|  |  | 
|  | config BLK_CGROUP | 
|  | tristate "Block IO controller" | 
|  | depends on BLOCK | 
|  | default n | 
|  | ---help--- | 
|  | Generic block IO controller cgroup interface. This is the common | 
|  | cgroup interface which should be used by various IO controlling | 
|  | policies. | 
|  |  | 
|  | Currently, CFQ IO scheduler uses it to recognize task groups and | 
|  | control disk bandwidth allocation (proportional time slice allocation) | 
|  | to such task groups. It is also used by bio throttling logic in | 
|  | block layer to implement upper limit in IO rates on a device. | 
|  |  | 
|  | This option only enables generic Block IO controller infrastructure. | 
|  | One needs to also enable actual IO controlling logic/policy. For | 
|  | enabling proportional weight division of disk bandwidth in CFQ, set | 
|  | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set | 
|  | CONFIG_BLK_DEV_THROTTLING=y. | 
|  |  | 
|  | See Documentation/cgroups/blkio-controller.txt for more information. | 
|  |  | 
|  | config DEBUG_BLK_CGROUP | 
|  | bool "Enable Block IO controller debugging" | 
|  | depends on BLK_CGROUP | 
|  | default n | 
|  | ---help--- | 
|  | Enable some debugging help. Currently it exports additional stat | 
|  | files in a cgroup which can be useful for debugging. | 
|  |  | 
|  | endif # CGROUPS | 
|  |  | 
|  | menuconfig NAMESPACES | 
|  | bool "Namespaces support" if EXPERT | 
|  | default !EXPERT | 
|  | help | 
|  | Provides the way to make tasks work with different objects using | 
|  | the same id. For example same IPC id may refer to different objects | 
|  | or same user id or pid may refer to different tasks when used in | 
|  | different namespaces. | 
|  |  | 
|  | if NAMESPACES | 
|  |  | 
|  | config UTS_NS | 
|  | bool "UTS namespace" | 
|  | default y | 
|  | help | 
|  | In this namespace tasks see different info provided with the | 
|  | uname() system call | 
|  |  | 
|  | config IPC_NS | 
|  | bool "IPC namespace" | 
|  | depends on (SYSVIPC || POSIX_MQUEUE) | 
|  | default y | 
|  | help | 
|  | In this namespace tasks work with IPC ids which correspond to | 
|  | different IPC objects in different namespaces. | 
|  |  | 
|  | config USER_NS | 
|  | bool "User namespace (EXPERIMENTAL)" | 
|  | depends on EXPERIMENTAL | 
|  | default y | 
|  | help | 
|  | This allows containers, i.e. vservers, to use user namespaces | 
|  | to provide different user info for different servers. | 
|  | If unsure, say N. | 
|  |  | 
|  | config PID_NS | 
|  | bool "PID Namespaces" | 
|  | default y | 
|  | help | 
|  | Support process id namespaces.  This allows having multiple | 
|  | processes with the same pid as long as they are in different | 
|  | pid namespaces.  This is a building block of containers. | 
|  |  | 
|  | config NET_NS | 
|  | bool "Network namespace" | 
|  | depends on NET | 
|  | default y | 
|  | help | 
|  | Allow user space to create what appear to be multiple instances | 
|  | of the network stack. | 
|  |  | 
|  | endif # NAMESPACES | 
|  |  | 
|  | config SCHED_AUTOGROUP | 
|  | bool "Automatic process group scheduling" | 
|  | select EVENTFD | 
|  | select CGROUPS | 
|  | select CGROUP_SCHED | 
|  | select FAIR_GROUP_SCHED | 
|  | help | 
|  | This option optimizes the scheduler for common desktop workloads by | 
|  | automatically creating and populating task groups.  This separation | 
|  | of workloads isolates aggressive CPU burners (like build jobs) from | 
|  | desktop applications.  Task group autogeneration is currently based | 
|  | upon task session. | 
|  |  | 
|  | config MM_OWNER | 
|  | bool | 
|  |  | 
|  | config SYSFS_DEPRECATED | 
|  | bool "Enable deprecated sysfs features to support old userspace tools" | 
|  | depends on SYSFS | 
|  | default n | 
|  | help | 
|  | This option adds code that switches the layout of the "block" class | 
|  | devices, to not show up in /sys/class/block/, but only in | 
|  | /sys/block/. | 
|  |  | 
|  | This switch is only active when the sysfs.deprecated=1 boot option is | 
|  | passed or the SYSFS_DEPRECATED_V2 option is set. | 
|  |  | 
|  | This option allows new kernels to run on old distributions and tools, | 
|  | which might get confused by /sys/class/block/. Since 2007/2008 all | 
|  | major distributions and tools handle this just fine. | 
|  |  | 
|  | Recent distributions and userspace tools after 2009/2010 depend on | 
|  | the existence of /sys/class/block/, and will not work with this | 
|  | option enabled. | 
|  |  | 
|  | Only if you are using a new kernel on an old distribution, you might | 
|  | need to say Y here. | 
|  |  | 
|  | config SYSFS_DEPRECATED_V2 | 
|  | bool "Enable deprecated sysfs features by default" | 
|  | default n | 
|  | depends on SYSFS | 
|  | depends on SYSFS_DEPRECATED | 
|  | help | 
|  | Enable deprecated sysfs by default. | 
|  |  | 
|  | See the CONFIG_SYSFS_DEPRECATED option for more details about this | 
|  | option. | 
|  |  | 
|  | Only if you are using a new kernel on an old distribution, you might | 
|  | need to say Y here. Even then, odds are you would not need it | 
|  | enabled, you can always pass the boot option if absolutely necessary. | 
|  |  | 
|  | config RELAY | 
|  | bool "Kernel->user space relay support (formerly relayfs)" | 
|  | help | 
|  | This option enables support for relay interface support in | 
|  | certain file systems (such as debugfs). | 
|  | It is designed to provide an efficient mechanism for tools and | 
|  | facilities to relay large amounts of data from kernel space to | 
|  | user space. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config BLK_DEV_INITRD | 
|  | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | 
|  | depends on BROKEN || !FRV | 
|  | help | 
|  | The initial RAM filesystem is a ramfs which is loaded by the | 
|  | boot loader (loadlin or lilo) and that is mounted as root | 
|  | before the normal boot procedure. It is typically used to | 
|  | load modules needed to mount the "real" root file system, | 
|  | etc. See <file:Documentation/initrd.txt> for details. | 
|  |  | 
|  | If RAM disk support (BLK_DEV_RAM) is also included, this | 
|  | also enables initial RAM disk (initrd) support and adds | 
|  | 15 Kbytes (more on some other architectures) to the kernel size. | 
|  |  | 
|  | If unsure say Y. | 
|  |  | 
|  | if BLK_DEV_INITRD | 
|  |  | 
|  | source "usr/Kconfig" | 
|  |  | 
|  | endif | 
|  |  | 
|  | config CC_OPTIMIZE_FOR_SIZE | 
|  | bool "Optimize for size" | 
|  | help | 
|  | Enabling this option will pass "-Os" instead of "-O2" to gcc | 
|  | resulting in a smaller kernel. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config SYSCTL | 
|  | bool | 
|  |  | 
|  | config ANON_INODES | 
|  | bool | 
|  |  | 
|  | menuconfig EXPERT | 
|  | bool "Configure standard kernel features (expert users)" | 
|  | help | 
|  | This option allows certain base kernel options and settings | 
|  | to be disabled or tweaked. This is for specialized | 
|  | environments which can tolerate a "non-standard" kernel. | 
|  | Only use this if you really know what you are doing. | 
|  |  | 
|  | config UID16 | 
|  | bool "Enable 16-bit UID system calls" if EXPERT | 
|  | depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) | 
|  | default y | 
|  | help | 
|  | This enables the legacy 16-bit UID syscall wrappers. | 
|  |  | 
|  | config SYSCTL_SYSCALL | 
|  | bool "Sysctl syscall support" if EXPERT | 
|  | depends on PROC_SYSCTL | 
|  | default 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 EXPERT | 
|  | default y | 
|  | help | 
|  | Say Y here to let the kernel print out symbolic crash information and | 
|  | symbolic stack backtraces. This increases the size of the kernel | 
|  | somewhat, as all symbols have to be loaded into the kernel image. | 
|  |  | 
|  | config KALLSYMS_ALL | 
|  | bool "Include all symbols in kallsyms" | 
|  | depends on DEBUG_KERNEL && KALLSYMS | 
|  | help | 
|  | Normally kallsyms only contains the symbols of functions for nicer | 
|  | OOPS messages and backtraces (i.e., symbols from the text and inittext | 
|  | sections). This is sufficient for most cases. And only in very rare | 
|  | cases (e.g., when a debugger is used) all symbols are required (e.g., | 
|  | names of variables from the data sections, etc). | 
|  |  | 
|  | This option makes sure that all symbols are loaded into the kernel | 
|  | image (i.e., symbols from all sections) in cost of increased kernel | 
|  | size (depending on the kernel configuration, it may be 300KiB or | 
|  | something like this). | 
|  |  | 
|  | Say N unless you really need all symbols. | 
|  |  | 
|  | config HOTPLUG | 
|  | bool "Support for hot-pluggable devices" if EXPERT | 
|  | default y | 
|  | help | 
|  | This option is provided for the case where no hotplug or uevent | 
|  | capabilities is wanted by the kernel.  You should only consider | 
|  | disabling this option for embedded systems that do not use modules, a | 
|  | dynamic /dev tree, or dynamic device discovery.  Just say Y. | 
|  |  | 
|  | config PRINTK | 
|  | default y | 
|  | bool "Enable support for printk" if EXPERT | 
|  | help | 
|  | This option enables normal printk support. Removing it | 
|  | eliminates most of the message strings from the kernel image | 
|  | and makes the kernel more or less silent. As this makes it | 
|  | very difficult to diagnose system problems, saying N here is | 
|  | strongly discouraged. | 
|  |  | 
|  | config BUG | 
|  | bool "BUG() support" if EXPERT | 
|  | default y | 
|  | help | 
|  | Disabling this option eliminates support for BUG and WARN, reducing | 
|  | the size of your kernel image and potentially quietly ignoring | 
|  | numerous fatal conditions. You should only consider disabling this | 
|  | option for embedded systems with no facilities for reporting errors. | 
|  | Just say Y. | 
|  |  | 
|  | config ELF_CORE | 
|  | default y | 
|  | bool "Enable ELF core dumps" if EXPERT | 
|  | help | 
|  | Enable support for generating core dumps. Disabling saves about 4k. | 
|  |  | 
|  | config PCSPKR_PLATFORM | 
|  | bool "Enable PC-Speaker support" if EXPERT | 
|  | depends on 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 EXPERT | 
|  | help | 
|  | Disabling this option reduces the size of miscellaneous core | 
|  | kernel data structures. This saves memory on small machines, | 
|  | but may reduce performance. | 
|  |  | 
|  | config FUTEX | 
|  | bool "Enable futex support" if EXPERT | 
|  | default y | 
|  | select RT_MUTEXES | 
|  | help | 
|  | Disabling this option will cause the kernel to be built without | 
|  | support for "fast userspace mutexes".  The resulting kernel may not | 
|  | run glibc-based applications correctly. | 
|  |  | 
|  | config EPOLL | 
|  | bool "Enable eventpoll support" if EXPERT | 
|  | default y | 
|  | select ANON_INODES | 
|  | help | 
|  | Disabling this option will cause the kernel to be built without | 
|  | support for epoll family of system calls. | 
|  |  | 
|  | config SIGNALFD | 
|  | bool "Enable signalfd() system call" if EXPERT | 
|  | select ANON_INODES | 
|  | default y | 
|  | help | 
|  | Enable the signalfd() system call that allows to receive signals | 
|  | on a file descriptor. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config TIMERFD | 
|  | bool "Enable timerfd() system call" if EXPERT | 
|  | select ANON_INODES | 
|  | default y | 
|  | help | 
|  | Enable the timerfd() system call that allows to receive timer | 
|  | events on a file descriptor. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config EVENTFD | 
|  | bool "Enable eventfd() system call" if EXPERT | 
|  | select ANON_INODES | 
|  | default y | 
|  | help | 
|  | Enable the eventfd() system call that allows to receive both | 
|  | kernel notification (ie. KAIO) or userspace notifications. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config SHMEM | 
|  | bool "Use full shmem filesystem" if EXPERT | 
|  | default y | 
|  | depends on MMU | 
|  | help | 
|  | The shmem is an internal filesystem used to manage shared memory. | 
|  | It is backed by swap and manages resource limits. It is also exported | 
|  | to userspace as tmpfs if TMPFS is enabled. Disabling this | 
|  | option replaces shmem and tmpfs with the much simpler ramfs code, | 
|  | which may be appropriate on small systems without swap. | 
|  |  | 
|  | config AIO | 
|  | bool "Enable AIO support" if EXPERT | 
|  | default y | 
|  | help | 
|  | This option enables POSIX asynchronous I/O which may by used | 
|  | by some high performance threaded applications. Disabling | 
|  | this option saves about 7k. | 
|  |  | 
|  | config EMBEDDED | 
|  | bool "Embedded system" | 
|  | select EXPERT | 
|  | help | 
|  | This option should be enabled if compiling the kernel for | 
|  | an embedded system so certain expert options are available | 
|  | for configuration. | 
|  |  | 
|  | config HAVE_PERF_EVENTS | 
|  | bool | 
|  | help | 
|  | See tools/perf/design.txt for details. | 
|  |  | 
|  | config PERF_USE_VMALLOC | 
|  | bool | 
|  | help | 
|  | See tools/perf/design.txt for details | 
|  |  | 
|  | menu "Kernel Performance Events And Counters" | 
|  |  | 
|  | config PERF_EVENTS | 
|  | bool "Kernel performance events and counters" | 
|  | default y if (PROFILING || PERF_COUNTERS) | 
|  | depends on HAVE_PERF_EVENTS | 
|  | select ANON_INODES | 
|  | select IRQ_WORK | 
|  | help | 
|  | Enable kernel support for various performance events provided | 
|  | by software and hardware. | 
|  |  | 
|  | Software events are supported either built-in or via the | 
|  | use of generic tracepoints. | 
|  |  | 
|  | Most modern CPUs support performance events via performance | 
|  | counter registers. These registers count the number of certain | 
|  | types of hw events: such as instructions executed, cachemisses | 
|  | suffered, or branches mis-predicted - without slowing down the | 
|  | kernel or applications. These registers can also trigger interrupts | 
|  | when a threshold number of events have passed - and can thus be | 
|  | used to profile the code that runs on that CPU. | 
|  |  | 
|  | The Linux Performance Event subsystem provides an abstraction of | 
|  | these software and hardware event capabilities, available via a | 
|  | system call and used by the "perf" utility in tools/perf/. It | 
|  | provides per task and per CPU counters, and it provides event | 
|  | capabilities on top of those. | 
|  |  | 
|  | Say Y if unsure. | 
|  |  | 
|  | config 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 EXPERT | 
|  | help | 
|  | VM event counters are needed for event counts to be shown. | 
|  | This option allows the disabling of the VM event counters | 
|  | on EXPERT systems.  /proc/vmstat will only show page counts | 
|  | if VM event counters are disabled. | 
|  |  | 
|  | config PCI_QUIRKS | 
|  | default y | 
|  | bool "Enable PCI quirk workarounds" if EXPERT | 
|  | depends on PCI | 
|  | help | 
|  | This enables workarounds for various PCI chipset | 
|  | bugs/quirks. Disable this only if your target machine is | 
|  | unaffected by PCI quirks. | 
|  |  | 
|  | config SLUB_DEBUG | 
|  | default y | 
|  | bool "Enable SLUB debugging support" if EXPERT | 
|  | depends on SLUB && SYSFS | 
|  | help | 
|  | SLUB has extensive debug support features. Disabling these can | 
|  | result in significant savings in code size. This also disables | 
|  | SLUB sysfs support. /sys/slab will not exist and there will be | 
|  | no support for cache validation etc. | 
|  |  | 
|  | config COMPAT_BRK | 
|  | bool "Disable heap randomization" | 
|  | default y | 
|  | help | 
|  | Randomizing heap placement makes heap exploits harder, but it | 
|  | also breaks ancient binaries (including anything libc5 based). | 
|  | This option changes the bootup default to heap randomization | 
|  | disabled, and can be overridden at runtime by setting | 
|  | /proc/sys/kernel/randomize_va_space to 2. | 
|  |  | 
|  | On non-ancient distros (post-2000 ones) N is usually a safe choice. | 
|  |  | 
|  | choice | 
|  | prompt "Choose SLAB allocator" | 
|  | default SLUB | 
|  | help | 
|  | This option allows to select a slab allocator. | 
|  |  | 
|  | config SLAB | 
|  | bool "SLAB" | 
|  | help | 
|  | The regular slab allocator that is established and known to work | 
|  | well in all environments. It organizes cache hot objects in | 
|  | per cpu and per node queues. | 
|  |  | 
|  | config SLUB | 
|  | bool "SLUB (Unqueued Allocator)" | 
|  | help | 
|  | SLUB is a slab allocator that minimizes cache line usage | 
|  | instead of managing queues of cached objects (SLAB approach). | 
|  | Per cpu caching is realized using slabs of objects instead | 
|  | of queues of objects. SLUB can use memory efficiently | 
|  | and has enhanced diagnostics. SLUB is the default choice for | 
|  | a slab allocator. | 
|  |  | 
|  | config SLOB | 
|  | depends on EXPERT | 
|  | bool "SLOB (Simple Allocator)" | 
|  | help | 
|  | SLOB replaces the stock allocator with a drastically simpler | 
|  | allocator. SLOB is generally more space efficient but | 
|  | does not perform as well on large systems. | 
|  |  | 
|  | endchoice | 
|  |  | 
|  | config MMAP_ALLOW_UNINITIALIZED | 
|  | bool "Allow mmapped anonymous memory to be uninitialized" | 
|  | depends on EXPERT && !MMU | 
|  | default n | 
|  | help | 
|  | Normally, and according to the Linux spec, anonymous memory obtained | 
|  | from mmap() has it's contents cleared before it is passed to | 
|  | userspace.  Enabling this config option allows you to request that | 
|  | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus | 
|  | providing a huge performance boost.  If this option is not enabled, | 
|  | then the flag will be ignored. | 
|  |  | 
|  | This is taken advantage of by uClibc's malloc(), and also by | 
|  | ELF-FDPIC binfmt's brk and stack allocator. | 
|  |  | 
|  | Because of the obvious security issues, this option should only be | 
|  | enabled on embedded devices where you control what is run in | 
|  | userspace.  Since that isn't generally a problem on no-MMU systems, | 
|  | it is normally safe to say Y here. | 
|  |  | 
|  | See Documentation/nommu-mmap.txt for more information. | 
|  |  | 
|  | config PROFILING | 
|  | bool "Profiling support" | 
|  | help | 
|  | Say Y here to enable the extended profiling support mechanisms used | 
|  | by profilers such as OProfile. | 
|  |  | 
|  | # | 
|  | # Place an empty function call at each tracepoint site. Can be | 
|  | # dynamically changed for a probe function. | 
|  | # | 
|  | config TRACEPOINTS | 
|  | bool | 
|  |  | 
|  | source "arch/Kconfig" | 
|  |  | 
|  | endmenu		# General setup | 
|  |  | 
|  | config HAVE_GENERIC_DMA_COHERENT | 
|  | bool | 
|  | default n | 
|  |  | 
|  | config SLABINFO | 
|  | bool | 
|  | depends on PROC_FS | 
|  | depends on SLAB || SLUB_DEBUG | 
|  | default y | 
|  |  | 
|  | config RT_MUTEXES | 
|  | boolean | 
|  |  | 
|  | config BASE_SMALL | 
|  | int | 
|  | default 0 if BASE_FULL | 
|  | default 1 if !BASE_FULL | 
|  |  | 
|  | menuconfig MODULES | 
|  | bool "Enable loadable module support" | 
|  | help | 
|  | Kernel modules are small pieces of compiled code which can | 
|  | be inserted in the running kernel, rather than being | 
|  | permanently built into the kernel.  You use the "modprobe" | 
|  | tool to add (and sometimes remove) them.  If you say Y here, | 
|  | many parts of the kernel can be built as modules (by | 
|  | answering M instead of Y where indicated): this is most | 
|  | useful for infrequently used options which are not required | 
|  | for booting.  For more information, see the man pages for | 
|  | modprobe, lsmod, modinfo, insmod and rmmod. | 
|  |  | 
|  | If you say Y here, you will need to run "make | 
|  | modules_install" to put the modules under /lib/modules/ | 
|  | where modprobe can find them (you may need to be root to do | 
|  | this). | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | if MODULES | 
|  |  | 
|  | config MODULE_FORCE_LOAD | 
|  | bool "Forced module loading" | 
|  | default n | 
|  | help | 
|  | Allow loading of modules without version information (ie. modprobe | 
|  | --force).  Forced module loading sets the 'F' (forced) taint flag and | 
|  | is usually a really bad idea. | 
|  |  | 
|  | config MODULE_UNLOAD | 
|  | bool "Module unloading" | 
|  | help | 
|  | Without this option you will not be able to unload any | 
|  | modules (note that some modules may not be unloadable | 
|  | anyway), which makes your kernel smaller, faster | 
|  | and simpler.  If unsure, say Y. | 
|  |  | 
|  | config MODULE_FORCE_UNLOAD | 
|  | bool "Forced module unloading" | 
|  | depends on MODULE_UNLOAD && EXPERIMENTAL | 
|  | help | 
|  | This option allows you to force a module to unload, even if the | 
|  | kernel believes it is unsafe: the kernel will remove the module | 
|  | without waiting for anyone to stop using it (using the -f option to | 
|  | rmmod).  This is mainly for kernel developers and desperate users. | 
|  | If unsure, say N. | 
|  |  | 
|  | config MODVERSIONS | 
|  | bool "Module versioning support" | 
|  | help | 
|  | Usually, you have to use modules compiled with your kernel. | 
|  | Saying Y here makes it sometimes possible to use modules | 
|  | compiled for different kernels, by adding enough information | 
|  | to the modules to (hopefully) spot any changes which would | 
|  | make them incompatible with the kernel you are running.  If | 
|  | unsure, say N. | 
|  |  | 
|  | config MODULE_SRCVERSION_ALL | 
|  | bool "Source checksum for all modules" | 
|  | help | 
|  | Modules which contain a MODULE_VERSION get an extra "srcversion" | 
|  | field inserted into their modinfo section, which contains a | 
|  | sum of the source files which made it.  This helps maintainers | 
|  | see exactly which source was used to build a module (since | 
|  | others sometimes change the module source without updating | 
|  | the version).  With this option, such a "srcversion" field | 
|  | will be created for all modules.  If unsure, say N. | 
|  |  | 
|  | endif # MODULES | 
|  |  | 
|  | config INIT_ALL_POSSIBLE | 
|  | bool | 
|  | help | 
|  | Back when each arch used to define their own cpu_online_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" |