7 option env="KERNELVERSION"
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
16 default "$ARCH_DEFCONFIG"
17 default "arch/$ARCH/defconfig"
26 config BUILDTIME_EXTABLE_SORT
32 bool "Prompt for development and/or incomplete code/drivers"
34 Some of the various things that Linux supports (such as network
35 drivers, file systems, network protocols, etc.) can be in a state
36 of development where the functionality, stability, or the level of
37 testing is not yet high enough for general use. This is usually
38 known as the "alpha-test" phase among developers. If a feature is
39 currently in alpha-test, then the developers usually discourage
40 uninformed widespread use of this feature by the general public to
41 avoid "Why doesn't this work?" type mail messages. However, active
42 testing and use of these systems is welcomed. Just be aware that it
43 may not meet the normal level of reliability or it may fail to work
44 in some special cases. Detailed bug reports from people familiar
45 with the kernel internals are usually welcomed by the developers
46 (before submitting bug reports, please read the documents
47 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
48 <file:Documentation/BUG-HUNTING>, and
49 <file:Documentation/oops-tracing.txt> in the kernel source).
51 This option will also make obsoleted drivers available. These are
52 drivers that have been replaced by something else, and/or are
53 scheduled to be removed in a future kernel release.
55 Unless you intend to help test and develop a feature or driver that
56 falls into this category, or you have a situation that requires
57 using these features, you should probably say N here, which will
58 cause the configurator to present you with fewer choices. If
59 you say Y here, you will be offered the choice of using features or
60 drivers that are currently considered to be in the alpha-test phase.
67 depends on BROKEN || !SMP
70 config INIT_ENV_ARG_LIMIT
75 Maximum of each of the number of arguments and environment
76 variables passed to init from the kernel command line.
80 string "Cross-compiler tool prefix"
82 Same as running 'make CROSS_COMPILE=prefix-' but stored for
83 default make runs in this kernel build directory. You don't
84 need to set this unless you want the configured kernel build
85 directory to select the cross-compiler automatically.
88 string "Local version - append to kernel release"
90 Append an extra string to the end of your kernel version.
91 This will show up when you type uname, for example.
92 The string you set here will be appended after the contents of
93 any files with a filename matching localversion* in your
94 object and source tree, in that order. Your total string can
95 be a maximum of 64 characters.
97 config LOCALVERSION_AUTO
98 bool "Automatically append version information to the version string"
101 This will try to automatically determine if the current tree is a
102 release tree by looking for git tags that belong to the current
103 top of tree revision.
105 A string of the format -gxxxxxxxx will be added to the localversion
106 if a git-based tree is found. The string generated by this will be
107 appended after any matching localversion* files, and after the value
108 set in CONFIG_LOCALVERSION.
110 (The actual string used here is the first eight characters produced
111 by running the command:
113 $ git rev-parse --verify HEAD
115 which is done within the script "scripts/setlocalversion".)
117 config HAVE_KERNEL_GZIP
120 config HAVE_KERNEL_BZIP2
123 config HAVE_KERNEL_LZMA
126 config HAVE_KERNEL_XZ
129 config HAVE_KERNEL_LZO
133 prompt "Kernel compression mode"
135 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
137 The linux kernel is a kind of self-extracting executable.
138 Several compression algorithms are available, which differ
139 in efficiency, compression and decompression speed.
140 Compression speed is only relevant when building a kernel.
141 Decompression speed is relevant at each boot.
143 If you have any problems with bzip2 or lzma compressed
144 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
145 version of this functionality (bzip2 only), for 2.4, was
146 supplied by Christian Ludwig)
148 High compression options are mostly useful for users, who
149 are low on disk space (embedded systems), but for whom ram
152 If in doubt, select 'gzip'
156 depends on HAVE_KERNEL_GZIP
158 The old and tried gzip compression. It provides a good balance
159 between compression ratio and decompression speed.
163 depends on HAVE_KERNEL_BZIP2
165 Its compression ratio and speed is intermediate.
166 Decompression speed is slowest among the choices. The kernel
167 size is about 10% smaller with bzip2, in comparison to gzip.
168 Bzip2 uses a large amount of memory. For modern kernels you
169 will need at least 8MB RAM or more for booting.
173 depends on HAVE_KERNEL_LZMA
175 This compression algorithm's ratio is best. Decompression speed
176 is between gzip and bzip2. Compression is slowest.
177 The kernel size is about 33% smaller with LZMA in comparison to gzip.
181 depends on HAVE_KERNEL_XZ
183 XZ uses the LZMA2 algorithm and instruction set specific
184 BCJ filters which can improve compression ratio of executable
185 code. The size of the kernel is about 30% smaller with XZ in
186 comparison to gzip. On architectures for which there is a BCJ
187 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
188 will create a few percent smaller kernel than plain LZMA.
190 The speed is about the same as with LZMA: The decompression
191 speed of XZ is better than that of bzip2 but worse than gzip
192 and LZO. Compression is slow.
196 depends on HAVE_KERNEL_LZO
198 Its compression ratio is the poorest among the choices. The kernel
199 size is about 10% bigger than gzip; however its speed
200 (both compression and decompression) is the fastest.
204 config DEFAULT_HOSTNAME
205 string "Default hostname"
208 This option determines the default system hostname before userspace
209 calls sethostname(2). The kernel traditionally uses "(none)" here,
210 but you may wish to use a different default here to make a minimal
211 system more usable with less configuration.
214 bool "Support for paging of anonymous memory (swap)"
215 depends on MMU && BLOCK
218 This option allows you to choose whether you want to have support
219 for so called swap devices or swap files in your kernel that are
220 used to provide more virtual memory than the actual RAM present
221 in your computer. If unsure say Y.
226 Inter Process Communication is a suite of library functions and
227 system calls which let processes (running programs) synchronize and
228 exchange information. It is generally considered to be a good thing,
229 and some programs won't run unless you say Y here. In particular, if
230 you want to run the DOS emulator dosemu under Linux (read the
231 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
232 you'll need to say Y here.
234 You can find documentation about IPC with "info ipc" and also in
235 section 6.4 of the Linux Programmer's Guide, available from
236 <http://www.tldp.org/guides.html>.
238 config SYSVIPC_SYSCTL
245 bool "POSIX Message Queues"
246 depends on NET && EXPERIMENTAL
248 POSIX variant of message queues is a part of IPC. In POSIX message
249 queues every message has a priority which decides about succession
250 of receiving it by a process. If you want to compile and run
251 programs written e.g. for Solaris with use of its POSIX message
252 queues (functions mq_*) say Y here.
254 POSIX message queues are visible as a filesystem called 'mqueue'
255 and can be mounted somewhere if you want to do filesystem
256 operations on message queues.
260 config POSIX_MQUEUE_SYSCTL
262 depends on POSIX_MQUEUE
267 bool "open by fhandle syscalls"
270 If you say Y here, a user level program will be able to map
271 file names to handle and then later use the handle for
272 different file system operations. This is useful in implementing
273 userspace file servers, which now track files using handles instead
274 of names. The handle would remain the same even if file names
275 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
279 bool "Auditing support"
282 Enable auditing infrastructure that can be used with another
283 kernel subsystem, such as SELinux (which requires this for
284 logging of avc messages output). Does not do system-call
285 auditing without CONFIG_AUDITSYSCALL.
288 bool "Enable system-call auditing support"
289 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
290 default y if SECURITY_SELINUX
292 Enable low-overhead system-call auditing infrastructure that
293 can be used independently or with another kernel subsystem,
298 depends on AUDITSYSCALL
303 depends on AUDITSYSCALL
306 config AUDIT_LOGINUID_IMMUTABLE
307 bool "Make audit loginuid immutable"
310 The config option toggles if a task setting its loginuid requires
311 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
312 but should instead only allow setting its loginuid if it was never
313 previously set. On systems which use systemd or a similar central
314 process to restart login services this should be set to true. On older
315 systems in which an admin would typically have to directly stop and
316 start processes this should be set to false. Setting this to true allows
317 one to drop potentially dangerous capabilites from the login tasks,
318 but may not be backwards compatible with older init systems.
320 source "kernel/irq/Kconfig"
321 source "kernel/time/Kconfig"
323 menu "CPU/Task time and stats accounting"
326 prompt "Cputime accounting"
327 default TICK_CPU_ACCOUNTING if !PPC64
328 default VIRT_CPU_ACCOUNTING if PPC64
330 # Kind of a stub config for the pure tick based cputime accounting
331 config TICK_CPU_ACCOUNTING
332 bool "Simple tick based cputime accounting"
335 This is the basic tick based cputime accounting that maintains
336 statistics about user, system and idle time spent on per jiffies
341 config VIRT_CPU_ACCOUNTING
342 bool "Deterministic task and CPU time accounting"
343 depends on HAVE_VIRT_CPU_ACCOUNTING
345 Select this option to enable more accurate task and CPU time
346 accounting. This is done by reading a CPU counter on each
347 kernel entry and exit and on transitions within the kernel
348 between system, softirq and hardirq state, so there is a
349 small performance impact. In the case of s390 or IBM POWER > 5,
350 this also enables accounting of stolen time on logically-partitioned
353 config IRQ_TIME_ACCOUNTING
354 bool "Fine granularity task level IRQ time accounting"
355 depends on HAVE_IRQ_TIME_ACCOUNTING
357 Select this option to enable fine granularity task irq time
358 accounting. This is done by reading a timestamp on each
359 transitions between softirq and hardirq state, so there can be a
360 small performance impact.
362 If in doubt, say N here.
366 config BSD_PROCESS_ACCT
367 bool "BSD Process Accounting"
369 If you say Y here, a user level program will be able to instruct the
370 kernel (via a special system call) to write process accounting
371 information to a file: whenever a process exits, information about
372 that process will be appended to the file by the kernel. The
373 information includes things such as creation time, owning user,
374 command name, memory usage, controlling terminal etc. (the complete
375 list is in the struct acct in <file:include/linux/acct.h>). It is
376 up to the user level program to do useful things with this
377 information. This is generally a good idea, so say Y.
379 config BSD_PROCESS_ACCT_V3
380 bool "BSD Process Accounting version 3 file format"
381 depends on BSD_PROCESS_ACCT
384 If you say Y here, the process accounting information is written
385 in a new file format that also logs the process IDs of each
386 process and it's parent. Note that this file format is incompatible
387 with previous v0/v1/v2 file formats, so you will need updated tools
388 for processing it. A preliminary version of these tools is available
389 at <http://www.gnu.org/software/acct/>.
392 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
396 Export selected statistics for tasks/processes through the
397 generic netlink interface. Unlike BSD process accounting, the
398 statistics are available during the lifetime of tasks/processes as
399 responses to commands. Like BSD accounting, they are sent to user
404 config TASK_DELAY_ACCT
405 bool "Enable per-task delay accounting (EXPERIMENTAL)"
408 Collect information on time spent by a task waiting for system
409 resources like cpu, synchronous block I/O completion and swapping
410 in pages. Such statistics can help in setting a task's priorities
411 relative to other tasks for cpu, io, rss limits etc.
416 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
419 Collect extended task accounting data and send the data
420 to userland for processing over the taskstats interface.
424 config TASK_IO_ACCOUNTING
425 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
426 depends on TASK_XACCT
428 Collect information on the number of bytes of storage I/O which this
433 endmenu # "CPU/Task time and stats accounting"
438 prompt "RCU Implementation"
442 bool "Tree-based hierarchical RCU"
443 depends on !PREEMPT && SMP
445 This option selects the RCU implementation that is
446 designed for very large SMP system with hundreds or
447 thousands of CPUs. It also scales down nicely to
450 config TREE_PREEMPT_RCU
451 bool "Preemptible tree-based hierarchical RCU"
454 This option selects the RCU implementation that is
455 designed for very large SMP systems with hundreds or
456 thousands of CPUs, but for which real-time response
457 is also required. It also scales down nicely to
460 Select this option if you are unsure.
463 bool "UP-only small-memory-footprint RCU"
464 depends on !PREEMPT && !SMP
466 This option selects the RCU implementation that is
467 designed for UP systems from which real-time response
468 is not required. This option greatly reduces the
469 memory footprint of RCU.
471 config TINY_PREEMPT_RCU
472 bool "Preemptible UP-only small-memory-footprint RCU"
473 depends on PREEMPT && !SMP
475 This option selects the RCU implementation that is designed
476 for real-time UP systems. This option greatly reduces the
477 memory footprint of RCU.
482 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
484 This option enables preemptible-RCU code that is common between
485 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
487 config RCU_STALL_COMMON
488 def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
490 This option enables RCU CPU stall code that is common between
491 the TINY and TREE variants of RCU. The purpose is to allow
492 the tiny variants to disable RCU CPU stall warnings, while
493 making these warnings mandatory for the tree variants.
495 config CONTEXT_TRACKING
499 bool "Consider userspace as in RCU extended quiescent state"
500 depends on HAVE_CONTEXT_TRACKING && SMP
501 select CONTEXT_TRACKING
503 This option sets hooks on kernel / userspace boundaries and
504 puts RCU in extended quiescent state when the CPU runs in
505 userspace. It means that when a CPU runs in userspace, it is
506 excluded from the global RCU state machine and thus doesn't
507 try to keep the timer tick on for RCU.
509 Unless you want to hack and help the development of the full
510 dynticks mode, you shouldn't enable this option. It also
511 adds unnecessary overhead.
515 config CONTEXT_TRACKING_FORCE
516 bool "Force context tracking"
517 depends on CONTEXT_TRACKING
519 Probe on user/kernel boundaries by default in order to
520 test the features that rely on it such as userspace RCU extended
522 This test is there for debugging until we have a real user like the
526 int "Tree-based hierarchical RCU fanout value"
529 depends on TREE_RCU || TREE_PREEMPT_RCU
533 This option controls the fanout of hierarchical implementations
534 of RCU, allowing RCU to work efficiently on machines with
535 large numbers of CPUs. This value must be at least the fourth
536 root of NR_CPUS, which allows NR_CPUS to be insanely large.
537 The default value of RCU_FANOUT should be used for production
538 systems, but if you are stress-testing the RCU implementation
539 itself, small RCU_FANOUT values allow you to test large-system
540 code paths on small(er) systems.
542 Select a specific number if testing RCU itself.
543 Take the default if unsure.
545 config RCU_FANOUT_LEAF
546 int "Tree-based hierarchical RCU leaf-level fanout value"
547 range 2 RCU_FANOUT if 64BIT
548 range 2 RCU_FANOUT if !64BIT
549 depends on TREE_RCU || TREE_PREEMPT_RCU
552 This option controls the leaf-level fanout of hierarchical
553 implementations of RCU, and allows trading off cache misses
554 against lock contention. Systems that synchronize their
555 scheduling-clock interrupts for energy-efficiency reasons will
556 want the default because the smaller leaf-level fanout keeps
557 lock contention levels acceptably low. Very large systems
558 (hundreds or thousands of CPUs) will instead want to set this
559 value to the maximum value possible in order to reduce the
560 number of cache misses incurred during RCU's grace-period
561 initialization. These systems tend to run CPU-bound, and thus
562 are not helped by synchronized interrupts, and thus tend to
563 skew them, which reduces lock contention enough that large
564 leaf-level fanouts work well.
566 Select a specific number if testing RCU itself.
568 Select the maximum permissible value for large systems.
570 Take the default if unsure.
572 config RCU_FANOUT_EXACT
573 bool "Disable tree-based hierarchical RCU auto-balancing"
574 depends on TREE_RCU || TREE_PREEMPT_RCU
577 This option forces use of the exact RCU_FANOUT value specified,
578 regardless of imbalances in the hierarchy. This is useful for
579 testing RCU itself, and might one day be useful on systems with
580 strong NUMA behavior.
582 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
586 config RCU_FAST_NO_HZ
587 bool "Accelerate last non-dyntick-idle CPU's grace periods"
588 depends on NO_HZ && SMP
591 This option causes RCU to attempt to accelerate grace periods in
592 order to allow CPUs to enter dynticks-idle state more quickly.
593 On the other hand, this option increases the overhead of the
594 dynticks-idle checking, thus degrading scheduling latency.
596 Say Y if energy efficiency is critically important, and you don't
597 care about real-time response.
599 Say N if you are unsure.
601 config TREE_RCU_TRACE
602 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
605 This option provides tracing for the TREE_RCU and
606 TREE_PREEMPT_RCU implementations, permitting Makefile to
607 trivially select kernel/rcutree_trace.c.
610 bool "Enable RCU priority boosting"
611 depends on RT_MUTEXES && PREEMPT_RCU
614 This option boosts the priority of preempted RCU readers that
615 block the current preemptible RCU grace period for too long.
616 This option also prevents heavy loads from blocking RCU
617 callback invocation for all flavors of RCU.
619 Say Y here if you are working with real-time apps or heavy loads
620 Say N here if you are unsure.
622 config RCU_BOOST_PRIO
623 int "Real-time priority to boost RCU readers to"
628 This option specifies the real-time priority to which long-term
629 preempted RCU readers are to be boosted. If you are working
630 with a real-time application that has one or more CPU-bound
631 threads running at a real-time priority level, you should set
632 RCU_BOOST_PRIO to a priority higher then the highest-priority
633 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
634 of 1 is appropriate in the common case, which is real-time
635 applications that do not have any CPU-bound threads.
637 Some real-time applications might not have a single real-time
638 thread that saturates a given CPU, but instead might have
639 multiple real-time threads that, taken together, fully utilize
640 that CPU. In this case, you should set RCU_BOOST_PRIO to
641 a priority higher than the lowest-priority thread that is
642 conspiring to prevent the CPU from running any non-real-time
643 tasks. For example, if one thread at priority 10 and another
644 thread at priority 5 are between themselves fully consuming
645 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
646 set to priority 6 or higher.
648 Specify the real-time priority, or take the default if unsure.
650 config RCU_BOOST_DELAY
651 int "Milliseconds to delay boosting after RCU grace-period start"
656 This option specifies the time to wait after the beginning of
657 a given grace period before priority-boosting preempted RCU
658 readers blocking that grace period. Note that any RCU reader
659 blocking an expedited RCU grace period is boosted immediately.
661 Accept the default if unsure.
664 bool "Offload RCU callback processing from boot-selected CPUs"
665 depends on TREE_RCU || TREE_PREEMPT_RCU
668 Use this option to reduce OS jitter for aggressive HPC or
669 real-time workloads. It can also be used to offload RCU
670 callback invocation to energy-efficient CPUs in battery-powered
671 asymmetric multiprocessors.
673 This option offloads callback invocation from the set of
674 CPUs specified at boot time by the rcu_nocbs parameter.
675 For each such CPU, a kthread ("rcuoN") will be created to
676 invoke callbacks, where the "N" is the CPU being offloaded.
677 Nothing prevents this kthread from running on the specified
678 CPUs, but (1) the kthreads may be preempted between each
679 callback, and (2) affinity or cgroups can be used to force
680 the kthreads to run on whatever set of CPUs is desired.
682 Say Y here if you want reduced OS jitter on selected CPUs.
683 Say N here if you are unsure.
685 endmenu # "RCU Subsystem"
688 tristate "Kernel .config support"
690 This option enables the complete Linux kernel ".config" file
691 contents to be saved in the kernel. It provides documentation
692 of which kernel options are used in a running kernel or in an
693 on-disk kernel. This information can be extracted from the kernel
694 image file with the script scripts/extract-ikconfig and used as
695 input to rebuild the current kernel or to build another kernel.
696 It can also be extracted from a running kernel by reading
697 /proc/config.gz if enabled (below).
700 bool "Enable access to .config through /proc/config.gz"
701 depends on IKCONFIG && PROC_FS
703 This option enables access to the kernel configuration file
704 through /proc/config.gz.
707 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
711 Select kernel log buffer size as a power of 2.
721 # Architectures with an unreliable sched_clock() should select this:
723 config HAVE_UNSTABLE_SCHED_CLOCK
727 # For architectures that want to enable the support for NUMA-affine scheduler
730 config ARCH_SUPPORTS_NUMA_BALANCING
733 # For architectures that (ab)use NUMA to represent different memory regions
734 # all cpu-local but of different latencies, such as SuperH.
736 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
740 # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE
741 config ARCH_WANTS_PROT_NUMA_PROT_NONE
744 config ARCH_USES_NUMA_PROT_NONE
747 depends on ARCH_WANTS_PROT_NUMA_PROT_NONE
748 depends on NUMA_BALANCING
750 config NUMA_BALANCING_DEFAULT_ENABLED
751 bool "Automatically enable NUMA aware memory/task placement"
753 depends on NUMA_BALANCING
755 If set, autonumic NUMA balancing will be enabled if running on a NUMA
758 config NUMA_BALANCING
759 bool "Memory placement aware NUMA scheduler"
760 depends on ARCH_SUPPORTS_NUMA_BALANCING
761 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
762 depends on SMP && NUMA && MIGRATION
764 This option adds support for automatic NUMA aware memory/task placement.
765 The mechanism is quite primitive and is based on migrating memory when
766 it is references to the node the task is running on.
768 This system will be inactive on UMA systems.
771 boolean "Control Group support"
774 This option adds support for grouping sets of processes together, for
775 use with process control subsystems such as Cpusets, CFS, memory
776 controls or device isolation.
778 - Documentation/scheduler/sched-design-CFS.txt (CFS)
779 - Documentation/cgroups/ (features for grouping, isolation
780 and resource control)
787 bool "Example debug cgroup subsystem"
790 This option enables a simple cgroup subsystem that
791 exports useful debugging information about the cgroups
796 config CGROUP_FREEZER
797 bool "Freezer cgroup subsystem"
799 Provides a way to freeze and unfreeze all tasks in a
803 bool "Device controller for cgroups"
805 Provides a cgroup implementing whitelists for devices which
806 a process in the cgroup can mknod or open.
809 bool "Cpuset support"
811 This option will let you create and manage CPUSETs which
812 allow dynamically partitioning a system into sets of CPUs and
813 Memory Nodes and assigning tasks to run only within those sets.
814 This is primarily useful on large SMP or NUMA systems.
818 config PROC_PID_CPUSET
819 bool "Include legacy /proc/<pid>/cpuset file"
823 config CGROUP_CPUACCT
824 bool "Simple CPU accounting cgroup subsystem"
826 Provides a simple Resource Controller for monitoring the
827 total CPU consumed by the tasks in a cgroup.
829 config RESOURCE_COUNTERS
830 bool "Resource counters"
832 This option enables controller independent resource accounting
833 infrastructure that works with cgroups.
836 bool "Memory Resource Controller for Control Groups"
837 depends on RESOURCE_COUNTERS
840 Provides a memory resource controller that manages both anonymous
841 memory and page cache. (See Documentation/cgroups/memory.txt)
843 Note that setting this option increases fixed memory overhead
844 associated with each page of memory in the system. By this,
845 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
846 usage tracking struct at boot. Total amount of this is printed out
849 Only enable when you're ok with these trade offs and really
850 sure you need the memory resource controller. Even when you enable
851 this, you can set "cgroup_disable=memory" at your boot option to
852 disable memory resource controller and you can avoid overheads.
853 (and lose benefits of memory resource controller)
855 This config option also selects MM_OWNER config option, which
856 could in turn add some fork/exit overhead.
859 bool "Memory Resource Controller Swap Extension"
860 depends on MEMCG && SWAP
862 Add swap management feature to memory resource controller. When you
863 enable this, you can limit mem+swap usage per cgroup. In other words,
864 when you disable this, memory resource controller has no cares to
865 usage of swap...a process can exhaust all of the swap. This extension
866 is useful when you want to avoid exhaustion swap but this itself
867 adds more overheads and consumes memory for remembering information.
868 Especially if you use 32bit system or small memory system, please
869 be careful about enabling this. When memory resource controller
870 is disabled by boot option, this will be automatically disabled and
871 there will be no overhead from this. Even when you set this config=y,
872 if boot option "swapaccount=0" is set, swap will not be accounted.
873 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
874 size is 4096bytes, 512k per 1Gbytes of swap.
875 config MEMCG_SWAP_ENABLED
876 bool "Memory Resource Controller Swap Extension enabled by default"
877 depends on MEMCG_SWAP
880 Memory Resource Controller Swap Extension comes with its price in
881 a bigger memory consumption. General purpose distribution kernels
882 which want to enable the feature but keep it disabled by default
883 and let the user enable it by swapaccount boot command line
884 parameter should have this option unselected.
885 For those who want to have the feature enabled by default should
886 select this option (if, for some reason, they need to disable it
887 then swapaccount=0 does the trick).
889 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
890 depends on MEMCG && EXPERIMENTAL
891 depends on SLUB || SLAB
893 The Kernel Memory extension for Memory Resource Controller can limit
894 the amount of memory used by kernel objects in the system. Those are
895 fundamentally different from the entities handled by the standard
896 Memory Controller, which are page-based, and can be swapped. Users of
897 the kmem extension can use it to guarantee that no group of processes
898 will ever exhaust kernel resources alone.
900 config CGROUP_HUGETLB
901 bool "HugeTLB Resource Controller for Control Groups"
902 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
905 Provides a cgroup Resource Controller for HugeTLB pages.
906 When you enable this, you can put a per cgroup limit on HugeTLB usage.
907 The limit is enforced during page fault. Since HugeTLB doesn't
908 support page reclaim, enforcing the limit at page fault time implies
909 that, the application will get SIGBUS signal if it tries to access
910 HugeTLB pages beyond its limit. This requires the application to know
911 beforehand how much HugeTLB pages it would require for its use. The
912 control group is tracked in the third page lru pointer. This means
913 that we cannot use the controller with huge page less than 3 pages.
916 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
917 depends on PERF_EVENTS && CGROUPS
919 This option extends the per-cpu mode to restrict monitoring to
920 threads which belong to the cgroup specified and run on the
925 menuconfig CGROUP_SCHED
926 bool "Group CPU scheduler"
929 This feature lets CPU scheduler recognize task groups and control CPU
930 bandwidth allocation to such task groups. It uses cgroups to group
934 config FAIR_GROUP_SCHED
935 bool "Group scheduling for SCHED_OTHER"
936 depends on CGROUP_SCHED
940 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
941 depends on EXPERIMENTAL
942 depends on FAIR_GROUP_SCHED
945 This option allows users to define CPU bandwidth rates (limits) for
946 tasks running within the fair group scheduler. Groups with no limit
947 set are considered to be unconstrained and will run with no
949 See tip/Documentation/scheduler/sched-bwc.txt for more information.
951 config RT_GROUP_SCHED
952 bool "Group scheduling for SCHED_RR/FIFO"
953 depends on EXPERIMENTAL
954 depends on CGROUP_SCHED
957 This feature lets you explicitly allocate real CPU bandwidth
958 to task groups. If enabled, it will also make it impossible to
959 schedule realtime tasks for non-root users until you allocate
960 realtime bandwidth for them.
961 See Documentation/scheduler/sched-rt-group.txt for more information.
966 bool "Block IO controller"
970 Generic block IO controller cgroup interface. This is the common
971 cgroup interface which should be used by various IO controlling
974 Currently, CFQ IO scheduler uses it to recognize task groups and
975 control disk bandwidth allocation (proportional time slice allocation)
976 to such task groups. It is also used by bio throttling logic in
977 block layer to implement upper limit in IO rates on a device.
979 This option only enables generic Block IO controller infrastructure.
980 One needs to also enable actual IO controlling logic/policy. For
981 enabling proportional weight division of disk bandwidth in CFQ, set
982 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
983 CONFIG_BLK_DEV_THROTTLING=y.
985 See Documentation/cgroups/blkio-controller.txt for more information.
987 config DEBUG_BLK_CGROUP
988 bool "Enable Block IO controller debugging"
989 depends on BLK_CGROUP
992 Enable some debugging help. Currently it exports additional stat
993 files in a cgroup which can be useful for debugging.
997 config CHECKPOINT_RESTORE
998 bool "Checkpoint/restore support" if EXPERT
1001 Enables additional kernel features in a sake of checkpoint/restore.
1002 In particular it adds auxiliary prctl codes to setup process text,
1003 data and heap segment sizes, and a few additional /proc filesystem
1006 If unsure, say N here.
1008 menuconfig NAMESPACES
1009 bool "Namespaces support" if EXPERT
1012 Provides the way to make tasks work with different objects using
1013 the same id. For example same IPC id may refer to different objects
1014 or same user id or pid may refer to different tasks when used in
1015 different namespaces.
1020 bool "UTS namespace"
1023 In this namespace tasks see different info provided with the
1027 bool "IPC namespace"
1028 depends on (SYSVIPC || POSIX_MQUEUE)
1031 In this namespace tasks work with IPC ids which correspond to
1032 different IPC objects in different namespaces.
1035 bool "User namespace (EXPERIMENTAL)"
1036 depends on EXPERIMENTAL
1037 depends on UIDGID_CONVERTED
1038 select UIDGID_STRICT_TYPE_CHECKS
1042 This allows containers, i.e. vservers, to use user namespaces
1043 to provide different user info for different servers.
1047 bool "PID Namespaces"
1050 Support process id namespaces. This allows having multiple
1051 processes with the same pid as long as they are in different
1052 pid namespaces. This is a building block of containers.
1055 bool "Network namespace"
1059 Allow user space to create what appear to be multiple instances
1060 of the network stack.
1064 config UIDGID_CONVERTED
1065 # True if all of the selected software conmponents are known
1066 # to have uid_t and gid_t converted to kuid_t and kgid_t
1067 # where appropriate and are otherwise safe to use with
1068 # the user namespace.
1073 depends on NET_9P = n
1076 depends on 9P_FS = n
1077 depends on AFS_FS = n
1078 depends on CEPH_FS = n
1080 depends on CODA_FS = n
1081 depends on GFS2_FS = n
1082 depends on NCP_FS = n
1084 depends on NFS_FS = n
1085 depends on OCFS2_FS = n
1086 depends on XFS_FS = n
1088 config UIDGID_STRICT_TYPE_CHECKS
1089 bool "Require conversions between uid/gids and their internal representation"
1090 depends on UIDGID_CONVERTED
1093 While the nececessary conversions are being added to all subsystems this option allows
1094 the code to continue to build for unconverted subsystems.
1096 Say Y here if you want the strict type checking enabled
1098 config SCHED_AUTOGROUP
1099 bool "Automatic process group scheduling"
1103 select FAIR_GROUP_SCHED
1105 This option optimizes the scheduler for common desktop workloads by
1106 automatically creating and populating task groups. This separation
1107 of workloads isolates aggressive CPU burners (like build jobs) from
1108 desktop applications. Task group autogeneration is currently based
1114 config SYSFS_DEPRECATED
1115 bool "Enable deprecated sysfs features to support old userspace tools"
1119 This option adds code that switches the layout of the "block" class
1120 devices, to not show up in /sys/class/block/, but only in
1123 This switch is only active when the sysfs.deprecated=1 boot option is
1124 passed or the SYSFS_DEPRECATED_V2 option is set.
1126 This option allows new kernels to run on old distributions and tools,
1127 which might get confused by /sys/class/block/. Since 2007/2008 all
1128 major distributions and tools handle this just fine.
1130 Recent distributions and userspace tools after 2009/2010 depend on
1131 the existence of /sys/class/block/, and will not work with this
1134 Only if you are using a new kernel on an old distribution, you might
1137 config SYSFS_DEPRECATED_V2
1138 bool "Enable deprecated sysfs features by default"
1141 depends on SYSFS_DEPRECATED
1143 Enable deprecated sysfs by default.
1145 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1148 Only if you are using a new kernel on an old distribution, you might
1149 need to say Y here. Even then, odds are you would not need it
1150 enabled, you can always pass the boot option if absolutely necessary.
1153 bool "Kernel->user space relay support (formerly relayfs)"
1155 This option enables support for relay interface support in
1156 certain file systems (such as debugfs).
1157 It is designed to provide an efficient mechanism for tools and
1158 facilities to relay large amounts of data from kernel space to
1163 config BLK_DEV_INITRD
1164 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1165 depends on BROKEN || !FRV
1167 The initial RAM filesystem is a ramfs which is loaded by the
1168 boot loader (loadlin or lilo) and that is mounted as root
1169 before the normal boot procedure. It is typically used to
1170 load modules needed to mount the "real" root file system,
1171 etc. See <file:Documentation/initrd.txt> for details.
1173 If RAM disk support (BLK_DEV_RAM) is also included, this
1174 also enables initial RAM disk (initrd) support and adds
1175 15 Kbytes (more on some other architectures) to the kernel size.
1181 source "usr/Kconfig"
1185 config CC_OPTIMIZE_FOR_SIZE
1186 bool "Optimize for size"
1188 Enabling this option will pass "-Os" instead of "-O2" to gcc
1189 resulting in a smaller kernel.
1200 bool "Configure standard kernel features (expert users)"
1201 # Unhide debug options, to make the on-by-default options visible
1204 This option allows certain base kernel options and settings
1205 to be disabled or tweaked. This is for specialized
1206 environments which can tolerate a "non-standard" kernel.
1207 Only use this if you really know what you are doing.
1213 bool "Enable 16-bit UID system calls" if EXPERT
1214 depends on HAVE_UID16
1217 This enables the legacy 16-bit UID syscall wrappers.
1219 config SYSCTL_SYSCALL
1220 bool "Sysctl syscall support" if EXPERT
1221 depends on PROC_SYSCTL
1225 sys_sysctl uses binary paths that have been found challenging
1226 to properly maintain and use. The interface in /proc/sys
1227 using paths with ascii names is now the primary path to this
1230 Almost nothing using the binary sysctl interface so if you are
1231 trying to save some space it is probably safe to disable this,
1232 making your kernel marginally smaller.
1234 If unsure say N here.
1236 config SYSCTL_EXCEPTION_TRACE
1239 Enable support for /proc/sys/debug/exception-trace.
1242 bool "Load all symbols for debugging/ksymoops" if EXPERT
1245 Say Y here to let the kernel print out symbolic crash information and
1246 symbolic stack backtraces. This increases the size of the kernel
1247 somewhat, as all symbols have to be loaded into the kernel image.
1250 bool "Include all symbols in kallsyms"
1251 depends on DEBUG_KERNEL && KALLSYMS
1253 Normally kallsyms only contains the symbols of functions for nicer
1254 OOPS messages and backtraces (i.e., symbols from the text and inittext
1255 sections). This is sufficient for most cases. And only in very rare
1256 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1257 names of variables from the data sections, etc).
1259 This option makes sure that all symbols are loaded into the kernel
1260 image (i.e., symbols from all sections) in cost of increased kernel
1261 size (depending on the kernel configuration, it may be 300KiB or
1262 something like this).
1264 Say N unless you really need all symbols.
1271 bool "Enable support for printk" if EXPERT
1274 This option enables normal printk support. Removing it
1275 eliminates most of the message strings from the kernel image
1276 and makes the kernel more or less silent. As this makes it
1277 very difficult to diagnose system problems, saying N here is
1278 strongly discouraged.
1281 bool "BUG() support" if EXPERT
1284 Disabling this option eliminates support for BUG and WARN, reducing
1285 the size of your kernel image and potentially quietly ignoring
1286 numerous fatal conditions. You should only consider disabling this
1287 option for embedded systems with no facilities for reporting errors.
1293 bool "Enable ELF core dumps" if EXPERT
1295 Enable support for generating core dumps. Disabling saves about 4k.
1298 config PCSPKR_PLATFORM
1299 bool "Enable PC-Speaker support" if EXPERT
1300 depends on HAVE_PCSPKR_PLATFORM
1304 This option allows to disable the internal PC-Speaker
1305 support, saving some memory.
1307 config HAVE_PCSPKR_PLATFORM
1312 bool "Enable full-sized data structures for core" if EXPERT
1314 Disabling this option reduces the size of miscellaneous core
1315 kernel data structures. This saves memory on small machines,
1316 but may reduce performance.
1319 bool "Enable futex support" if EXPERT
1323 Disabling this option will cause the kernel to be built without
1324 support for "fast userspace mutexes". The resulting kernel may not
1325 run glibc-based applications correctly.
1328 bool "Enable eventpoll support" if EXPERT
1332 Disabling this option will cause the kernel to be built without
1333 support for epoll family of system calls.
1336 bool "Enable signalfd() system call" if EXPERT
1340 Enable the signalfd() system call that allows to receive signals
1341 on a file descriptor.
1346 bool "Enable timerfd() system call" if EXPERT
1350 Enable the timerfd() system call that allows to receive timer
1351 events on a file descriptor.
1356 bool "Enable eventfd() system call" if EXPERT
1360 Enable the eventfd() system call that allows to receive both
1361 kernel notification (ie. KAIO) or userspace notifications.
1366 bool "Use full shmem filesystem" if EXPERT
1370 The shmem is an internal filesystem used to manage shared memory.
1371 It is backed by swap and manages resource limits. It is also exported
1372 to userspace as tmpfs if TMPFS is enabled. Disabling this
1373 option replaces shmem and tmpfs with the much simpler ramfs code,
1374 which may be appropriate on small systems without swap.
1377 bool "Enable AIO support" if EXPERT
1380 This option enables POSIX asynchronous I/O which may by used
1381 by some high performance threaded applications. Disabling
1382 this option saves about 7k.
1385 bool "Embedded system"
1388 This option should be enabled if compiling the kernel for
1389 an embedded system so certain expert options are available
1392 config HAVE_PERF_EVENTS
1395 See tools/perf/design.txt for details.
1397 config PERF_USE_VMALLOC
1400 See tools/perf/design.txt for details
1402 menu "Kernel Performance Events And Counters"
1405 bool "Kernel performance events and counters"
1406 default y if PROFILING
1407 depends on HAVE_PERF_EVENTS
1411 Enable kernel support for various performance events provided
1412 by software and hardware.
1414 Software events are supported either built-in or via the
1415 use of generic tracepoints.
1417 Most modern CPUs support performance events via performance
1418 counter registers. These registers count the number of certain
1419 types of hw events: such as instructions executed, cachemisses
1420 suffered, or branches mis-predicted - without slowing down the
1421 kernel or applications. These registers can also trigger interrupts
1422 when a threshold number of events have passed - and can thus be
1423 used to profile the code that runs on that CPU.
1425 The Linux Performance Event subsystem provides an abstraction of
1426 these software and hardware event capabilities, available via a
1427 system call and used by the "perf" utility in tools/perf/. It
1428 provides per task and per CPU counters, and it provides event
1429 capabilities on top of those.
1433 config DEBUG_PERF_USE_VMALLOC
1435 bool "Debug: use vmalloc to back perf mmap() buffers"
1436 depends on PERF_EVENTS && DEBUG_KERNEL
1437 select PERF_USE_VMALLOC
1439 Use vmalloc memory to back perf mmap() buffers.
1441 Mostly useful for debugging the vmalloc code on platforms
1442 that don't require it.
1448 config VM_EVENT_COUNTERS
1450 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1452 VM event counters are needed for event counts to be shown.
1453 This option allows the disabling of the VM event counters
1454 on EXPERT systems. /proc/vmstat will only show page counts
1455 if VM event counters are disabled.
1459 bool "Enable PCI quirk workarounds" if EXPERT
1462 This enables workarounds for various PCI chipset
1463 bugs/quirks. Disable this only if your target machine is
1464 unaffected by PCI quirks.
1468 bool "Enable SLUB debugging support" if EXPERT
1469 depends on SLUB && SYSFS
1471 SLUB has extensive debug support features. Disabling these can
1472 result in significant savings in code size. This also disables
1473 SLUB sysfs support. /sys/slab will not exist and there will be
1474 no support for cache validation etc.
1477 bool "Disable heap randomization"
1480 Randomizing heap placement makes heap exploits harder, but it
1481 also breaks ancient binaries (including anything libc5 based).
1482 This option changes the bootup default to heap randomization
1483 disabled, and can be overridden at runtime by setting
1484 /proc/sys/kernel/randomize_va_space to 2.
1486 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1489 prompt "Choose SLAB allocator"
1492 This option allows to select a slab allocator.
1497 The regular slab allocator that is established and known to work
1498 well in all environments. It organizes cache hot objects in
1499 per cpu and per node queues.
1502 bool "SLUB (Unqueued Allocator)"
1504 SLUB is a slab allocator that minimizes cache line usage
1505 instead of managing queues of cached objects (SLAB approach).
1506 Per cpu caching is realized using slabs of objects instead
1507 of queues of objects. SLUB can use memory efficiently
1508 and has enhanced diagnostics. SLUB is the default choice for
1513 bool "SLOB (Simple Allocator)"
1515 SLOB replaces the stock allocator with a drastically simpler
1516 allocator. SLOB is generally more space efficient but
1517 does not perform as well on large systems.
1521 config MMAP_ALLOW_UNINITIALIZED
1522 bool "Allow mmapped anonymous memory to be uninitialized"
1523 depends on EXPERT && !MMU
1526 Normally, and according to the Linux spec, anonymous memory obtained
1527 from mmap() has it's contents cleared before it is passed to
1528 userspace. Enabling this config option allows you to request that
1529 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1530 providing a huge performance boost. If this option is not enabled,
1531 then the flag will be ignored.
1533 This is taken advantage of by uClibc's malloc(), and also by
1534 ELF-FDPIC binfmt's brk and stack allocator.
1536 Because of the obvious security issues, this option should only be
1537 enabled on embedded devices where you control what is run in
1538 userspace. Since that isn't generally a problem on no-MMU systems,
1539 it is normally safe to say Y here.
1541 See Documentation/nommu-mmap.txt for more information.
1544 bool "Profiling support"
1546 Say Y here to enable the extended profiling support mechanisms used
1547 by profilers such as OProfile.
1550 # Place an empty function call at each tracepoint site. Can be
1551 # dynamically changed for a probe function.
1556 source "arch/Kconfig"
1558 endmenu # General setup
1560 config HAVE_GENERIC_DMA_COHERENT
1567 depends on SLAB || SLUB_DEBUG
1575 default 0 if BASE_FULL
1576 default 1 if !BASE_FULL
1579 bool "Enable loadable module support"
1581 Kernel modules are small pieces of compiled code which can
1582 be inserted in the running kernel, rather than being
1583 permanently built into the kernel. You use the "modprobe"
1584 tool to add (and sometimes remove) them. If you say Y here,
1585 many parts of the kernel can be built as modules (by
1586 answering M instead of Y where indicated): this is most
1587 useful for infrequently used options which are not required
1588 for booting. For more information, see the man pages for
1589 modprobe, lsmod, modinfo, insmod and rmmod.
1591 If you say Y here, you will need to run "make
1592 modules_install" to put the modules under /lib/modules/
1593 where modprobe can find them (you may need to be root to do
1600 config MODULE_FORCE_LOAD
1601 bool "Forced module loading"
1604 Allow loading of modules without version information (ie. modprobe
1605 --force). Forced module loading sets the 'F' (forced) taint flag and
1606 is usually a really bad idea.
1608 config MODULE_UNLOAD
1609 bool "Module unloading"
1611 Without this option you will not be able to unload any
1612 modules (note that some modules may not be unloadable
1613 anyway), which makes your kernel smaller, faster
1614 and simpler. If unsure, say Y.
1616 config MODULE_FORCE_UNLOAD
1617 bool "Forced module unloading"
1618 depends on MODULE_UNLOAD && EXPERIMENTAL
1620 This option allows you to force a module to unload, even if the
1621 kernel believes it is unsafe: the kernel will remove the module
1622 without waiting for anyone to stop using it (using the -f option to
1623 rmmod). This is mainly for kernel developers and desperate users.
1627 bool "Module versioning support"
1629 Usually, you have to use modules compiled with your kernel.
1630 Saying Y here makes it sometimes possible to use modules
1631 compiled for different kernels, by adding enough information
1632 to the modules to (hopefully) spot any changes which would
1633 make them incompatible with the kernel you are running. If
1636 config MODULE_SRCVERSION_ALL
1637 bool "Source checksum for all modules"
1639 Modules which contain a MODULE_VERSION get an extra "srcversion"
1640 field inserted into their modinfo section, which contains a
1641 sum of the source files which made it. This helps maintainers
1642 see exactly which source was used to build a module (since
1643 others sometimes change the module source without updating
1644 the version). With this option, such a "srcversion" field
1645 will be created for all modules. If unsure, say N.
1648 bool "Module signature verification"
1652 select ASYMMETRIC_KEY_TYPE
1653 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1654 select PUBLIC_KEY_ALGO_RSA
1657 select X509_CERTIFICATE_PARSER
1659 Check modules for valid signatures upon load: the signature
1660 is simply appended to the module. For more information see
1661 Documentation/module-signing.txt.
1663 !!!WARNING!!! If you enable this option, you MUST make sure that the
1664 module DOES NOT get stripped after being signed. This includes the
1665 debuginfo strip done by some packagers (such as rpmbuild) and
1666 inclusion into an initramfs that wants the module size reduced.
1668 config MODULE_SIG_FORCE
1669 bool "Require modules to be validly signed"
1670 depends on MODULE_SIG
1672 Reject unsigned modules or signed modules for which we don't have a
1673 key. Without this, such modules will simply taint the kernel.
1676 prompt "Which hash algorithm should modules be signed with?"
1677 depends on MODULE_SIG
1679 This determines which sort of hashing algorithm will be used during
1680 signature generation. This algorithm _must_ be built into the kernel
1681 directly so that signature verification can take place. It is not
1682 possible to load a signed module containing the algorithm to check
1683 the signature on that module.
1685 config MODULE_SIG_SHA1
1686 bool "Sign modules with SHA-1"
1689 config MODULE_SIG_SHA224
1690 bool "Sign modules with SHA-224"
1691 select CRYPTO_SHA256
1693 config MODULE_SIG_SHA256
1694 bool "Sign modules with SHA-256"
1695 select CRYPTO_SHA256
1697 config MODULE_SIG_SHA384
1698 bool "Sign modules with SHA-384"
1699 select CRYPTO_SHA512
1701 config MODULE_SIG_SHA512
1702 bool "Sign modules with SHA-512"
1703 select CRYPTO_SHA512
1709 config INIT_ALL_POSSIBLE
1712 Back when each arch used to define their own cpu_online_mask and
1713 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
1714 with all 1s, and others with all 0s. When they were centralised,
1715 it was better to provide this option than to break all the archs
1716 and have several arch maintainers pursuing me down dark alleys.
1721 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1723 Need stop_machine() primitive.
1725 source "block/Kconfig"
1727 config PREEMPT_NOTIFIERS
1734 # Can be selected by architectures with broken toolchains
1735 # that get confused by correct const<->read_only section
1737 config BROKEN_RODATA
1743 Build a simple ASN.1 grammar compiler that produces a bytecode output
1744 that can be interpreted by the ASN.1 stream decoder and used to
1745 inform it as to what tags are to be expected in a stream and what
1746 functions to call on what tags.
1748 source "kernel/Kconfig.locks"
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