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"
28 depends on HAVE_IRQ_WORK
33 bool "Prompt for development and/or incomplete code/drivers"
35 Some of the various things that Linux supports (such as network
36 drivers, file systems, network protocols, etc.) can be in a state
37 of development where the functionality, stability, or the level of
38 testing is not yet high enough for general use. This is usually
39 known as the "alpha-test" phase among developers. If a feature is
40 currently in alpha-test, then the developers usually discourage
41 uninformed widespread use of this feature by the general public to
42 avoid "Why doesn't this work?" type mail messages. However, active
43 testing and use of these systems is welcomed. Just be aware that it
44 may not meet the normal level of reliability or it may fail to work
45 in some special cases. Detailed bug reports from people familiar
46 with the kernel internals are usually welcomed by the developers
47 (before submitting bug reports, please read the documents
48 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
49 <file:Documentation/BUG-HUNTING>, and
50 <file:Documentation/oops-tracing.txt> in the kernel source).
52 This option will also make obsoleted drivers available. These are
53 drivers that have been replaced by something else, and/or are
54 scheduled to be removed in a future kernel release.
56 Unless you intend to help test and develop a feature or driver that
57 falls into this category, or you have a situation that requires
58 using these features, you should probably say N here, which will
59 cause the configurator to present you with fewer choices. If
60 you say Y here, you will be offered the choice of using features or
61 drivers that are currently considered to be in the alpha-test phase.
68 depends on BROKEN || !SMP
71 config INIT_ENV_ARG_LIMIT
76 Maximum of each of the number of arguments and environment
77 variables passed to init from the kernel command line.
81 string "Cross-compiler tool prefix"
83 Same as running 'make CROSS_COMPILE=prefix-' but stored for
84 default make runs in this kernel build directory. You don't
85 need to set this unless you want the configured kernel build
86 directory to select the cross-compiler automatically.
89 string "Local version - append to kernel release"
91 Append an extra string to the end of your kernel version.
92 This will show up when you type uname, for example.
93 The string you set here will be appended after the contents of
94 any files with a filename matching localversion* in your
95 object and source tree, in that order. Your total string can
96 be a maximum of 64 characters.
98 config LOCALVERSION_AUTO
99 bool "Automatically append version information to the version string"
102 This will try to automatically determine if the current tree is a
103 release tree by looking for git tags that belong to the current
104 top of tree revision.
106 A string of the format -gxxxxxxxx will be added to the localversion
107 if a git-based tree is found. The string generated by this will be
108 appended after any matching localversion* files, and after the value
109 set in CONFIG_LOCALVERSION.
111 (The actual string used here is the first eight characters produced
112 by running the command:
114 $ git rev-parse --verify HEAD
116 which is done within the script "scripts/setlocalversion".)
118 config HAVE_KERNEL_GZIP
121 config HAVE_KERNEL_BZIP2
124 config HAVE_KERNEL_LZMA
127 config HAVE_KERNEL_XZ
130 config HAVE_KERNEL_LZO
134 prompt "Kernel compression mode"
136 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
138 The linux kernel is a kind of self-extracting executable.
139 Several compression algorithms are available, which differ
140 in efficiency, compression and decompression speed.
141 Compression speed is only relevant when building a kernel.
142 Decompression speed is relevant at each boot.
144 If you have any problems with bzip2 or lzma compressed
145 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
146 version of this functionality (bzip2 only), for 2.4, was
147 supplied by Christian Ludwig)
149 High compression options are mostly useful for users, who
150 are low on disk space (embedded systems), but for whom ram
153 If in doubt, select 'gzip'
157 depends on HAVE_KERNEL_GZIP
159 The old and tried gzip compression. It provides a good balance
160 between compression ratio and decompression speed.
164 depends on HAVE_KERNEL_BZIP2
166 Its compression ratio and speed is intermediate.
167 Decompression speed is slowest among the three. The kernel
168 size is about 10% smaller with bzip2, in comparison to gzip.
169 Bzip2 uses a large amount of memory. For modern kernels you
170 will need at least 8MB RAM or more for booting.
174 depends on HAVE_KERNEL_LZMA
176 The most recent compression algorithm.
177 Its ratio is best, decompression speed is between the other
178 two. Compression is slowest. The kernel size is about 33%
179 smaller with LZMA in comparison to gzip.
183 depends on HAVE_KERNEL_XZ
185 XZ uses the LZMA2 algorithm and instruction set specific
186 BCJ filters which can improve compression ratio of executable
187 code. The size of the kernel is about 30% smaller with XZ in
188 comparison to gzip. On architectures for which there is a BCJ
189 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
190 will create a few percent smaller kernel than plain LZMA.
192 The speed is about the same as with LZMA: The decompression
193 speed of XZ is better than that of bzip2 but worse than gzip
194 and LZO. Compression is slow.
198 depends on HAVE_KERNEL_LZO
200 Its compression ratio is the poorest among the 4. The kernel
201 size is about 10% bigger than gzip; however its speed
202 (both compression and decompression) is the fastest.
206 config DEFAULT_HOSTNAME
207 string "Default hostname"
210 This option determines the default system hostname before userspace
211 calls sethostname(2). The kernel traditionally uses "(none)" here,
212 but you may wish to use a different default here to make a minimal
213 system more usable with less configuration.
216 bool "Support for paging of anonymous memory (swap)"
217 depends on MMU && BLOCK
220 This option allows you to choose whether you want to have support
221 for so called swap devices or swap files in your kernel that are
222 used to provide more virtual memory than the actual RAM present
223 in your computer. If unsure say Y.
228 Inter Process Communication is a suite of library functions and
229 system calls which let processes (running programs) synchronize and
230 exchange information. It is generally considered to be a good thing,
231 and some programs won't run unless you say Y here. In particular, if
232 you want to run the DOS emulator dosemu under Linux (read the
233 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
234 you'll need to say Y here.
236 You can find documentation about IPC with "info ipc" and also in
237 section 6.4 of the Linux Programmer's Guide, available from
238 <http://www.tldp.org/guides.html>.
240 config SYSVIPC_SYSCTL
247 bool "POSIX Message Queues"
248 depends on NET && EXPERIMENTAL
250 POSIX variant of message queues is a part of IPC. In POSIX message
251 queues every message has a priority which decides about succession
252 of receiving it by a process. If you want to compile and run
253 programs written e.g. for Solaris with use of its POSIX message
254 queues (functions mq_*) say Y here.
256 POSIX message queues are visible as a filesystem called 'mqueue'
257 and can be mounted somewhere if you want to do filesystem
258 operations on message queues.
262 config POSIX_MQUEUE_SYSCTL
264 depends on POSIX_MQUEUE
268 config BSD_PROCESS_ACCT
269 bool "BSD Process Accounting"
271 If you say Y here, a user level program will be able to instruct the
272 kernel (via a special system call) to write process accounting
273 information to a file: whenever a process exits, information about
274 that process will be appended to the file by the kernel. The
275 information includes things such as creation time, owning user,
276 command name, memory usage, controlling terminal etc. (the complete
277 list is in the struct acct in <file:include/linux/acct.h>). It is
278 up to the user level program to do useful things with this
279 information. This is generally a good idea, so say Y.
281 config BSD_PROCESS_ACCT_V3
282 bool "BSD Process Accounting version 3 file format"
283 depends on BSD_PROCESS_ACCT
286 If you say Y here, the process accounting information is written
287 in a new file format that also logs the process IDs of each
288 process and it's parent. Note that this file format is incompatible
289 with previous v0/v1/v2 file formats, so you will need updated tools
290 for processing it. A preliminary version of these tools is available
291 at <http://www.gnu.org/software/acct/>.
294 bool "open by fhandle syscalls"
297 If you say Y here, a user level program will be able to map
298 file names to handle and then later use the handle for
299 different file system operations. This is useful in implementing
300 userspace file servers, which now track files using handles instead
301 of names. The handle would remain the same even if file names
302 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
306 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
310 Export selected statistics for tasks/processes through the
311 generic netlink interface. Unlike BSD process accounting, the
312 statistics are available during the lifetime of tasks/processes as
313 responses to commands. Like BSD accounting, they are sent to user
318 config TASK_DELAY_ACCT
319 bool "Enable per-task delay accounting (EXPERIMENTAL)"
322 Collect information on time spent by a task waiting for system
323 resources like cpu, synchronous block I/O completion and swapping
324 in pages. Such statistics can help in setting a task's priorities
325 relative to other tasks for cpu, io, rss limits etc.
330 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
333 Collect extended task accounting data and send the data
334 to userland for processing over the taskstats interface.
338 config TASK_IO_ACCOUNTING
339 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
340 depends on TASK_XACCT
342 Collect information on the number of bytes of storage I/O which this
348 bool "Auditing support"
351 Enable auditing infrastructure that can be used with another
352 kernel subsystem, such as SELinux (which requires this for
353 logging of avc messages output). Does not do system-call
354 auditing without CONFIG_AUDITSYSCALL.
357 bool "Enable system-call auditing support"
358 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || ARM)
359 default y if SECURITY_SELINUX
361 Enable low-overhead system-call auditing infrastructure that
362 can be used independently or with another kernel subsystem,
367 depends on AUDITSYSCALL
372 depends on AUDITSYSCALL
375 config AUDIT_LOGINUID_IMMUTABLE
376 bool "Make audit loginuid immutable"
379 The config option toggles if a task setting its loginuid requires
380 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
381 but should instead only allow setting its loginuid if it was never
382 previously set. On systems which use systemd or a similar central
383 process to restart login services this should be set to true. On older
384 systems in which an admin would typically have to directly stop and
385 start processes this should be set to false. Setting this to true allows
386 one to drop potentially dangerous capabilites from the login tasks,
387 but may not be backwards compatible with older init systems.
389 source "kernel/irq/Kconfig"
394 prompt "RCU Implementation"
398 bool "Tree-based hierarchical RCU"
399 depends on !PREEMPT && SMP
401 This option selects the RCU implementation that is
402 designed for very large SMP system with hundreds or
403 thousands of CPUs. It also scales down nicely to
406 config TREE_PREEMPT_RCU
407 bool "Preemptible tree-based hierarchical RCU"
408 depends on PREEMPT && SMP
410 This option selects the RCU implementation that is
411 designed for very large SMP systems with hundreds or
412 thousands of CPUs, but for which real-time response
413 is also required. It also scales down nicely to
417 bool "UP-only small-memory-footprint RCU"
418 depends on !PREEMPT && !SMP
420 This option selects the RCU implementation that is
421 designed for UP systems from which real-time response
422 is not required. This option greatly reduces the
423 memory footprint of RCU.
425 config TINY_PREEMPT_RCU
426 bool "Preemptible UP-only small-memory-footprint RCU"
427 depends on PREEMPT && !SMP
429 This option selects the RCU implementation that is designed
430 for real-time UP systems. This option greatly reduces the
431 memory footprint of RCU.
436 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
438 This option enables preemptible-RCU code that is common between
439 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
442 int "Tree-based hierarchical RCU fanout value"
445 depends on TREE_RCU || TREE_PREEMPT_RCU
449 This option controls the fanout of hierarchical implementations
450 of RCU, allowing RCU to work efficiently on machines with
451 large numbers of CPUs. This value must be at least the fourth
452 root of NR_CPUS, which allows NR_CPUS to be insanely large.
453 The default value of RCU_FANOUT should be used for production
454 systems, but if you are stress-testing the RCU implementation
455 itself, small RCU_FANOUT values allow you to test large-system
456 code paths on small(er) systems.
458 Select a specific number if testing RCU itself.
459 Take the default if unsure.
461 config RCU_FANOUT_EXACT
462 bool "Disable tree-based hierarchical RCU auto-balancing"
463 depends on TREE_RCU || TREE_PREEMPT_RCU
466 This option forces use of the exact RCU_FANOUT value specified,
467 regardless of imbalances in the hierarchy. This is useful for
468 testing RCU itself, and might one day be useful on systems with
469 strong NUMA behavior.
471 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
475 config RCU_FAST_NO_HZ
476 bool "Accelerate last non-dyntick-idle CPU's grace periods"
477 depends on NO_HZ && SMP
480 This option causes RCU to attempt to accelerate grace periods
481 in order to allow CPUs to enter dynticks-idle state more
482 quickly. On the other hand, this option increases the overhead
483 of the dynticks-idle checking, particularly on systems with
484 large numbers of CPUs.
486 Say Y if energy efficiency is critically important, particularly
487 if you have relatively few CPUs.
489 Say N if you are unsure.
491 config TREE_RCU_TRACE
492 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
495 This option provides tracing for the TREE_RCU and
496 TREE_PREEMPT_RCU implementations, permitting Makefile to
497 trivially select kernel/rcutree_trace.c.
500 bool "Enable RCU priority boosting"
501 depends on RT_MUTEXES && PREEMPT_RCU
504 This option boosts the priority of preempted RCU readers that
505 block the current preemptible RCU grace period for too long.
506 This option also prevents heavy loads from blocking RCU
507 callback invocation for all flavors of RCU.
509 Say Y here if you are working with real-time apps or heavy loads
510 Say N here if you are unsure.
512 config RCU_BOOST_PRIO
513 int "Real-time priority to boost RCU readers to"
518 This option specifies the real-time priority to which preempted
519 RCU readers are to be boosted. If you are working with CPU-bound
520 real-time applications, you should specify a priority higher then
521 the highest-priority CPU-bound application.
523 Specify the real-time priority, or take the default if unsure.
525 config RCU_BOOST_DELAY
526 int "Milliseconds to delay boosting after RCU grace-period start"
531 This option specifies the time to wait after the beginning of
532 a given grace period before priority-boosting preempted RCU
533 readers blocking that grace period. Note that any RCU reader
534 blocking an expedited RCU grace period is boosted immediately.
536 Accept the default if unsure.
538 endmenu # "RCU Subsystem"
541 tristate "Kernel .config support"
543 This option enables the complete Linux kernel ".config" file
544 contents to be saved in the kernel. It provides documentation
545 of which kernel options are used in a running kernel or in an
546 on-disk kernel. This information can be extracted from the kernel
547 image file with the script scripts/extract-ikconfig and used as
548 input to rebuild the current kernel or to build another kernel.
549 It can also be extracted from a running kernel by reading
550 /proc/config.gz if enabled (below).
553 bool "Enable access to .config through /proc/config.gz"
554 depends on IKCONFIG && PROC_FS
556 This option enables access to the kernel configuration file
557 through /proc/config.gz.
560 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
564 Select kernel log buffer size as a power of 2.
574 # Architectures with an unreliable sched_clock() should select this:
576 config HAVE_UNSTABLE_SCHED_CLOCK
580 boolean "Control Group support"
583 This option adds support for grouping sets of processes together, for
584 use with process control subsystems such as Cpusets, CFS, memory
585 controls or device isolation.
587 - Documentation/scheduler/sched-design-CFS.txt (CFS)
588 - Documentation/cgroups/ (features for grouping, isolation
589 and resource control)
596 bool "Example debug cgroup subsystem"
599 This option enables a simple cgroup subsystem that
600 exports useful debugging information about the cgroups
605 config CGROUP_FREEZER
606 bool "Freezer cgroup subsystem"
608 Provides a way to freeze and unfreeze all tasks in a
612 bool "Device controller for cgroups"
614 Provides a cgroup implementing whitelists for devices which
615 a process in the cgroup can mknod or open.
618 bool "Cpuset support"
620 This option will let you create and manage CPUSETs which
621 allow dynamically partitioning a system into sets of CPUs and
622 Memory Nodes and assigning tasks to run only within those sets.
623 This is primarily useful on large SMP or NUMA systems.
627 config PROC_PID_CPUSET
628 bool "Include legacy /proc/<pid>/cpuset file"
632 config CGROUP_CPUACCT
633 bool "Simple CPU accounting cgroup subsystem"
635 Provides a simple Resource Controller for monitoring the
636 total CPU consumed by the tasks in a cgroup.
638 config RESOURCE_COUNTERS
639 bool "Resource counters"
641 This option enables controller independent resource accounting
642 infrastructure that works with cgroups.
644 config CGROUP_MEM_RES_CTLR
645 bool "Memory Resource Controller for Control Groups"
646 depends on RESOURCE_COUNTERS
649 Provides a memory resource controller that manages both anonymous
650 memory and page cache. (See Documentation/cgroups/memory.txt)
652 Note that setting this option increases fixed memory overhead
653 associated with each page of memory in the system. By this,
654 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
655 usage tracking struct at boot. Total amount of this is printed out
658 Only enable when you're ok with these trade offs and really
659 sure you need the memory resource controller. Even when you enable
660 this, you can set "cgroup_disable=memory" at your boot option to
661 disable memory resource controller and you can avoid overheads.
662 (and lose benefits of memory resource controller)
664 This config option also selects MM_OWNER config option, which
665 could in turn add some fork/exit overhead.
667 config CGROUP_MEM_RES_CTLR_SWAP
668 bool "Memory Resource Controller Swap Extension"
669 depends on CGROUP_MEM_RES_CTLR && SWAP
671 Add swap management feature to memory resource controller. When you
672 enable this, you can limit mem+swap usage per cgroup. In other words,
673 when you disable this, memory resource controller has no cares to
674 usage of swap...a process can exhaust all of the swap. This extension
675 is useful when you want to avoid exhaustion swap but this itself
676 adds more overheads and consumes memory for remembering information.
677 Especially if you use 32bit system or small memory system, please
678 be careful about enabling this. When memory resource controller
679 is disabled by boot option, this will be automatically disabled and
680 there will be no overhead from this. Even when you set this config=y,
681 if boot option "swapaccount=0" is set, swap will not be accounted.
682 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
683 size is 4096bytes, 512k per 1Gbytes of swap.
684 config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
685 bool "Memory Resource Controller Swap Extension enabled by default"
686 depends on CGROUP_MEM_RES_CTLR_SWAP
689 Memory Resource Controller Swap Extension comes with its price in
690 a bigger memory consumption. General purpose distribution kernels
691 which want to enable the feature but keep it disabled by default
692 and let the user enable it by swapaccount boot command line
693 parameter should have this option unselected.
694 For those who want to have the feature enabled by default should
695 select this option (if, for some reason, they need to disable it
696 then swapaccount=0 does the trick).
697 config CGROUP_MEM_RES_CTLR_KMEM
698 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
699 depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
702 The Kernel Memory extension for Memory Resource Controller can limit
703 the amount of memory used by kernel objects in the system. Those are
704 fundamentally different from the entities handled by the standard
705 Memory Controller, which are page-based, and can be swapped. Users of
706 the kmem extension can use it to guarantee that no group of processes
707 will ever exhaust kernel resources alone.
710 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
711 depends on PERF_EVENTS && CGROUPS
713 This option extends the per-cpu mode to restrict monitoring to
714 threads which belong to the cgroup specified and run on the
719 menuconfig CGROUP_SCHED
720 bool "Group CPU scheduler"
723 This feature lets CPU scheduler recognize task groups and control CPU
724 bandwidth allocation to such task groups. It uses cgroups to group
728 config FAIR_GROUP_SCHED
729 bool "Group scheduling for SCHED_OTHER"
730 depends on CGROUP_SCHED
734 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
735 depends on EXPERIMENTAL
736 depends on FAIR_GROUP_SCHED
739 This option allows users to define CPU bandwidth rates (limits) for
740 tasks running within the fair group scheduler. Groups with no limit
741 set are considered to be unconstrained and will run with no
743 See tip/Documentation/scheduler/sched-bwc.txt for more information.
745 config RT_GROUP_SCHED
746 bool "Group scheduling for SCHED_RR/FIFO"
747 depends on EXPERIMENTAL
748 depends on CGROUP_SCHED
751 This feature lets you explicitly allocate real CPU bandwidth
752 to task groups. If enabled, it will also make it impossible to
753 schedule realtime tasks for non-root users until you allocate
754 realtime bandwidth for them.
755 See Documentation/scheduler/sched-rt-group.txt for more information.
760 tristate "Block IO controller"
764 Generic block IO controller cgroup interface. This is the common
765 cgroup interface which should be used by various IO controlling
768 Currently, CFQ IO scheduler uses it to recognize task groups and
769 control disk bandwidth allocation (proportional time slice allocation)
770 to such task groups. It is also used by bio throttling logic in
771 block layer to implement upper limit in IO rates on a device.
773 This option only enables generic Block IO controller infrastructure.
774 One needs to also enable actual IO controlling logic/policy. For
775 enabling proportional weight division of disk bandwidth in CFQ, set
776 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
777 CONFIG_BLK_DEV_THROTTLING=y.
779 See Documentation/cgroups/blkio-controller.txt for more information.
781 config DEBUG_BLK_CGROUP
782 bool "Enable Block IO controller debugging"
783 depends on BLK_CGROUP
786 Enable some debugging help. Currently it exports additional stat
787 files in a cgroup which can be useful for debugging.
791 config CHECKPOINT_RESTORE
792 bool "Checkpoint/restore support" if EXPERT
795 Enables additional kernel features in a sake of checkpoint/restore.
796 In particular it adds auxiliary prctl codes to setup process text,
797 data and heap segment sizes, and a few additional /proc filesystem
800 If unsure, say N here.
802 menuconfig NAMESPACES
803 bool "Namespaces support" if EXPERT
806 Provides the way to make tasks work with different objects using
807 the same id. For example same IPC id may refer to different objects
808 or same user id or pid may refer to different tasks when used in
809 different namespaces.
817 In this namespace tasks see different info provided with the
822 depends on (SYSVIPC || POSIX_MQUEUE)
825 In this namespace tasks work with IPC ids which correspond to
826 different IPC objects in different namespaces.
829 bool "User namespace (EXPERIMENTAL)"
830 depends on EXPERIMENTAL
831 depends on UIDGID_CONVERTED
832 select UIDGID_STRICT_TYPE_CHECKS
836 This allows containers, i.e. vservers, to use user namespaces
837 to provide different user info for different servers.
841 bool "PID Namespaces"
844 Support process id namespaces. This allows having multiple
845 processes with the same pid as long as they are in different
846 pid namespaces. This is a building block of containers.
849 bool "Network namespace"
853 Allow user space to create what appear to be multiple instances
854 of the network stack.
858 config UIDGID_CONVERTED
859 # True if all of the selected software conmponents are known
860 # to have uid_t and gid_t converted to kuid_t and kgid_t
861 # where appropriate and are otherwise safe to use with
862 # the user namespace.
866 # List of kernel pieces that need user namespace work
868 depends on CGROUPS = n
869 depends on MIGRATION = n
871 depends on SYSVIPC = n
876 depends on AUDITSYSCALL = n
877 depends on TASKSTATS = n
878 depends on TRACING = n
879 depends on FS_POSIX_ACL = n
881 depends on QUOTACTL = n
882 depends on DEBUG_CREDENTIALS = n
883 depends on BSD_PROCESS_ACCT = n
885 depends on PROC_EVENTS = n
889 depends on NET_9P = n
891 depends on PHONET = n
892 depends on NET_CLS_FLOW = n
893 depends on NETFILTER_XT_MATCH_OWNER = n
894 depends on NETFILTER_XT_MATCH_RECENT = n
895 depends on NETFILTER_XT_TARGET_LOG = n
896 depends on NETFILTER_NETLINK_LOG = n
899 depends on IP_SCTP = n
900 depends on AF_RXRPC = n
902 depends on NET_KEY = n
903 depends on INET_DIAG = n
904 depends on DNS_RESOLVER = n
909 depends on USB_DEVICEFS = n
910 depends on USB_GADGETFS = n
911 depends on USB_FUNCTIONFS = n
912 depends on DEVTMPFS = n
916 depends on ADFS_FS = n
917 depends on AFFS_FS = n
918 depends on AFS_FS = n
919 depends on AUTOFS4_FS = n
920 depends on BEFS_FS = n
921 depends on BFS_FS = n
922 depends on BTRFS_FS = n
923 depends on CEPH_FS = n
925 depends on CODA_FS = n
926 depends on CONFIGFS_FS = n
927 depends on CRAMFS = n
928 depends on DEBUG_FS = n
929 depends on ECRYPT_FS = n
930 depends on EFS_FS = n
931 depends on EXOFS_FS = n
932 depends on EXT2_FS = n
933 depends on EXT3_FS = n
934 depends on EXT4_FS = n
935 depends on FAT_FS = n
936 depends on FUSE_FS = n
937 depends on GFS2_FS = n
938 depends on HFS_FS = n
939 depends on HFSPLUS_FS = n
940 depends on HPFS_FS = n
941 depends on HUGETLBFS = n
942 depends on ISO9660_FS = n
943 depends on JFFS2_FS = n
944 depends on JFS_FS = n
946 depends on MINIX_FS = n
947 depends on NCP_FS = n
949 depends on NFS_FS = n
950 depends on NILFS2_FS = n
951 depends on NTFS_FS = n
952 depends on OCFS2_FS = n
953 depends on OMFS_FS = n
954 depends on PROC_FS = n
955 depends on PROC_SYSCTL = n
956 depends on QNX4FS_FS = n
957 depends on QNX6FS_FS = n
958 depends on REISERFS_FS = n
959 depends on SQUASHFS = n
961 depends on SYSV_FS = n
963 depends on UBIFS_FS = n
964 depends on UDF_FS = n
965 depends on UFS_FS = n
966 depends on VXFS_FS = n
967 depends on XFS_FS = n
969 depends on !UML || HOSTFS = n
971 # The rare drivers that won't build
973 depends on AIRO_CS = n
975 depends on INFINIBAND_QIB = n
976 depends on BLK_DEV_LOOP = n
977 depends on ANDROID_BINDER_IPC = n
980 depends on SECURITY_TOMOYO = n
981 depends on SECURITY_APPARMOR = n
983 config UIDGID_STRICT_TYPE_CHECKS
984 bool "Require conversions between uid/gids and their internal representation"
985 depends on UIDGID_CONVERTED
988 While the nececessary conversions are being added to all subsystems this option allows
989 the code to continue to build for unconverted subsystems.
991 Say Y here if you want the strict type checking enabled
993 config SCHED_AUTOGROUP
994 bool "Automatic process group scheduling"
998 select FAIR_GROUP_SCHED
1000 This option optimizes the scheduler for common desktop workloads by
1001 automatically creating and populating task groups. This separation
1002 of workloads isolates aggressive CPU burners (like build jobs) from
1003 desktop applications. Task group autogeneration is currently based
1009 config SYSFS_DEPRECATED
1010 bool "Enable deprecated sysfs features to support old userspace tools"
1014 This option adds code that switches the layout of the "block" class
1015 devices, to not show up in /sys/class/block/, but only in
1018 This switch is only active when the sysfs.deprecated=1 boot option is
1019 passed or the SYSFS_DEPRECATED_V2 option is set.
1021 This option allows new kernels to run on old distributions and tools,
1022 which might get confused by /sys/class/block/. Since 2007/2008 all
1023 major distributions and tools handle this just fine.
1025 Recent distributions and userspace tools after 2009/2010 depend on
1026 the existence of /sys/class/block/, and will not work with this
1029 Only if you are using a new kernel on an old distribution, you might
1032 config SYSFS_DEPRECATED_V2
1033 bool "Enable deprecated sysfs features by default"
1036 depends on SYSFS_DEPRECATED
1038 Enable deprecated sysfs by default.
1040 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1043 Only if you are using a new kernel on an old distribution, you might
1044 need to say Y here. Even then, odds are you would not need it
1045 enabled, you can always pass the boot option if absolutely necessary.
1048 bool "Kernel->user space relay support (formerly relayfs)"
1050 This option enables support for relay interface support in
1051 certain file systems (such as debugfs).
1052 It is designed to provide an efficient mechanism for tools and
1053 facilities to relay large amounts of data from kernel space to
1058 config BLK_DEV_INITRD
1059 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1060 depends on BROKEN || !FRV
1062 The initial RAM filesystem is a ramfs which is loaded by the
1063 boot loader (loadlin or lilo) and that is mounted as root
1064 before the normal boot procedure. It is typically used to
1065 load modules needed to mount the "real" root file system,
1066 etc. See <file:Documentation/initrd.txt> for details.
1068 If RAM disk support (BLK_DEV_RAM) is also included, this
1069 also enables initial RAM disk (initrd) support and adds
1070 15 Kbytes (more on some other architectures) to the kernel size.
1076 source "usr/Kconfig"
1080 config CC_OPTIMIZE_FOR_SIZE
1081 bool "Optimize for size"
1083 Enabling this option will pass "-Os" instead of "-O2" to gcc
1084 resulting in a smaller kernel.
1095 bool "Configure standard kernel features (expert users)"
1096 # Unhide debug options, to make the on-by-default options visible
1099 This option allows certain base kernel options and settings
1100 to be disabled or tweaked. This is for specialized
1101 environments which can tolerate a "non-standard" kernel.
1102 Only use this if you really know what you are doing.
1105 bool "Enable 16-bit UID system calls" if EXPERT
1106 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
1109 This enables the legacy 16-bit UID syscall wrappers.
1111 config SYSCTL_SYSCALL
1112 bool "Sysctl syscall support" if EXPERT
1113 depends on PROC_SYSCTL
1117 sys_sysctl uses binary paths that have been found challenging
1118 to properly maintain and use. The interface in /proc/sys
1119 using paths with ascii names is now the primary path to this
1122 Almost nothing using the binary sysctl interface so if you are
1123 trying to save some space it is probably safe to disable this,
1124 making your kernel marginally smaller.
1126 If unsure say N here.
1129 bool "Load all symbols for debugging/ksymoops" if EXPERT
1132 Say Y here to let the kernel print out symbolic crash information and
1133 symbolic stack backtraces. This increases the size of the kernel
1134 somewhat, as all symbols have to be loaded into the kernel image.
1137 bool "Include all symbols in kallsyms"
1138 depends on DEBUG_KERNEL && KALLSYMS
1140 Normally kallsyms only contains the symbols of functions for nicer
1141 OOPS messages and backtraces (i.e., symbols from the text and inittext
1142 sections). This is sufficient for most cases. And only in very rare
1143 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1144 names of variables from the data sections, etc).
1146 This option makes sure that all symbols are loaded into the kernel
1147 image (i.e., symbols from all sections) in cost of increased kernel
1148 size (depending on the kernel configuration, it may be 300KiB or
1149 something like this).
1151 Say N unless you really need all symbols.
1154 bool "Support for hot-pluggable devices" if EXPERT
1157 This option is provided for the case where no hotplug or uevent
1158 capabilities is wanted by the kernel. You should only consider
1159 disabling this option for embedded systems that do not use modules, a
1160 dynamic /dev tree, or dynamic device discovery. Just say Y.
1164 bool "Enable support for printk" if EXPERT
1166 This option enables normal printk support. Removing it
1167 eliminates most of the message strings from the kernel image
1168 and makes the kernel more or less silent. As this makes it
1169 very difficult to diagnose system problems, saying N here is
1170 strongly discouraged.
1173 bool "BUG() support" if EXPERT
1176 Disabling this option eliminates support for BUG and WARN, reducing
1177 the size of your kernel image and potentially quietly ignoring
1178 numerous fatal conditions. You should only consider disabling this
1179 option for embedded systems with no facilities for reporting errors.
1184 bool "Enable ELF core dumps" if EXPERT
1186 Enable support for generating core dumps. Disabling saves about 4k.
1189 config PCSPKR_PLATFORM
1190 bool "Enable PC-Speaker support" if EXPERT
1191 depends on HAVE_PCSPKR_PLATFORM
1195 This option allows to disable the internal PC-Speaker
1196 support, saving some memory.
1198 config HAVE_PCSPKR_PLATFORM
1203 bool "Enable full-sized data structures for core" if EXPERT
1205 Disabling this option reduces the size of miscellaneous core
1206 kernel data structures. This saves memory on small machines,
1207 but may reduce performance.
1210 bool "Enable futex support" if EXPERT
1214 Disabling this option will cause the kernel to be built without
1215 support for "fast userspace mutexes". The resulting kernel may not
1216 run glibc-based applications correctly.
1219 bool "Enable eventpoll support" if EXPERT
1223 Disabling this option will cause the kernel to be built without
1224 support for epoll family of system calls.
1227 bool "Enable signalfd() system call" if EXPERT
1231 Enable the signalfd() system call that allows to receive signals
1232 on a file descriptor.
1237 bool "Enable timerfd() system call" if EXPERT
1241 Enable the timerfd() system call that allows to receive timer
1242 events on a file descriptor.
1247 bool "Enable eventfd() system call" if EXPERT
1251 Enable the eventfd() system call that allows to receive both
1252 kernel notification (ie. KAIO) or userspace notifications.
1257 bool "Use full shmem filesystem" if EXPERT
1261 The shmem is an internal filesystem used to manage shared memory.
1262 It is backed by swap and manages resource limits. It is also exported
1263 to userspace as tmpfs if TMPFS is enabled. Disabling this
1264 option replaces shmem and tmpfs with the much simpler ramfs code,
1265 which may be appropriate on small systems without swap.
1268 bool "Enable AIO support" if EXPERT
1271 This option enables POSIX asynchronous I/O which may by used
1272 by some high performance threaded applications. Disabling
1273 this option saves about 7k.
1276 bool "Embedded system"
1279 This option should be enabled if compiling the kernel for
1280 an embedded system so certain expert options are available
1283 config HAVE_PERF_EVENTS
1286 See tools/perf/design.txt for details.
1288 config PERF_USE_VMALLOC
1291 See tools/perf/design.txt for details
1293 menu "Kernel Performance Events And Counters"
1296 bool "Kernel performance events and counters"
1297 default y if (PROFILING || PERF_COUNTERS)
1298 depends on HAVE_PERF_EVENTS
1302 Enable kernel support for various performance events provided
1303 by software and hardware.
1305 Software events are supported either built-in or via the
1306 use of generic tracepoints.
1308 Most modern CPUs support performance events via performance
1309 counter registers. These registers count the number of certain
1310 types of hw events: such as instructions executed, cachemisses
1311 suffered, or branches mis-predicted - without slowing down the
1312 kernel or applications. These registers can also trigger interrupts
1313 when a threshold number of events have passed - and can thus be
1314 used to profile the code that runs on that CPU.
1316 The Linux Performance Event subsystem provides an abstraction of
1317 these software and hardware event capabilities, available via a
1318 system call and used by the "perf" utility in tools/perf/. It
1319 provides per task and per CPU counters, and it provides event
1320 capabilities on top of those.
1324 config PERF_COUNTERS
1325 bool "Kernel performance counters (old config option)"
1326 depends on HAVE_PERF_EVENTS
1328 This config has been obsoleted by the PERF_EVENTS
1329 config option - please see that one for details.
1331 It has no effect on the kernel whether you enable
1332 it or not, it is a compatibility placeholder.
1336 config DEBUG_PERF_USE_VMALLOC
1338 bool "Debug: use vmalloc to back perf mmap() buffers"
1339 depends on PERF_EVENTS && DEBUG_KERNEL
1340 select PERF_USE_VMALLOC
1342 Use vmalloc memory to back perf mmap() buffers.
1344 Mostly useful for debugging the vmalloc code on platforms
1345 that don't require it.
1351 config VM_EVENT_COUNTERS
1353 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1355 VM event counters are needed for event counts to be shown.
1356 This option allows the disabling of the VM event counters
1357 on EXPERT systems. /proc/vmstat will only show page counts
1358 if VM event counters are disabled.
1362 bool "Enable PCI quirk workarounds" if EXPERT
1365 This enables workarounds for various PCI chipset
1366 bugs/quirks. Disable this only if your target machine is
1367 unaffected by PCI quirks.
1371 bool "Enable SLUB debugging support" if EXPERT
1372 depends on SLUB && SYSFS
1374 SLUB has extensive debug support features. Disabling these can
1375 result in significant savings in code size. This also disables
1376 SLUB sysfs support. /sys/slab will not exist and there will be
1377 no support for cache validation etc.
1380 bool "Disable heap randomization"
1383 Randomizing heap placement makes heap exploits harder, but it
1384 also breaks ancient binaries (including anything libc5 based).
1385 This option changes the bootup default to heap randomization
1386 disabled, and can be overridden at runtime by setting
1387 /proc/sys/kernel/randomize_va_space to 2.
1389 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1392 prompt "Choose SLAB allocator"
1395 This option allows to select a slab allocator.
1400 The regular slab allocator that is established and known to work
1401 well in all environments. It organizes cache hot objects in
1402 per cpu and per node queues.
1405 bool "SLUB (Unqueued Allocator)"
1407 SLUB is a slab allocator that minimizes cache line usage
1408 instead of managing queues of cached objects (SLAB approach).
1409 Per cpu caching is realized using slabs of objects instead
1410 of queues of objects. SLUB can use memory efficiently
1411 and has enhanced diagnostics. SLUB is the default choice for
1416 bool "SLOB (Simple Allocator)"
1418 SLOB replaces the stock allocator with a drastically simpler
1419 allocator. SLOB is generally more space efficient but
1420 does not perform as well on large systems.
1424 config MMAP_ALLOW_UNINITIALIZED
1425 bool "Allow mmapped anonymous memory to be uninitialized"
1426 depends on EXPERT && !MMU
1429 Normally, and according to the Linux spec, anonymous memory obtained
1430 from mmap() has it's contents cleared before it is passed to
1431 userspace. Enabling this config option allows you to request that
1432 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1433 providing a huge performance boost. If this option is not enabled,
1434 then the flag will be ignored.
1436 This is taken advantage of by uClibc's malloc(), and also by
1437 ELF-FDPIC binfmt's brk and stack allocator.
1439 Because of the obvious security issues, this option should only be
1440 enabled on embedded devices where you control what is run in
1441 userspace. Since that isn't generally a problem on no-MMU systems,
1442 it is normally safe to say Y here.
1444 See Documentation/nommu-mmap.txt for more information.
1447 bool "Profiling support"
1449 Say Y here to enable the extended profiling support mechanisms used
1450 by profilers such as OProfile.
1453 # Place an empty function call at each tracepoint site. Can be
1454 # dynamically changed for a probe function.
1459 source "arch/Kconfig"
1461 endmenu # General setup
1463 config HAVE_GENERIC_DMA_COHERENT
1470 depends on SLAB || SLUB_DEBUG
1478 default 0 if BASE_FULL
1479 default 1 if !BASE_FULL
1482 bool "Enable loadable module support"
1484 Kernel modules are small pieces of compiled code which can
1485 be inserted in the running kernel, rather than being
1486 permanently built into the kernel. You use the "modprobe"
1487 tool to add (and sometimes remove) them. If you say Y here,
1488 many parts of the kernel can be built as modules (by
1489 answering M instead of Y where indicated): this is most
1490 useful for infrequently used options which are not required
1491 for booting. For more information, see the man pages for
1492 modprobe, lsmod, modinfo, insmod and rmmod.
1494 If you say Y here, you will need to run "make
1495 modules_install" to put the modules under /lib/modules/
1496 where modprobe can find them (you may need to be root to do
1503 config MODULE_FORCE_LOAD
1504 bool "Forced module loading"
1507 Allow loading of modules without version information (ie. modprobe
1508 --force). Forced module loading sets the 'F' (forced) taint flag and
1509 is usually a really bad idea.
1511 config MODULE_UNLOAD
1512 bool "Module unloading"
1514 Without this option you will not be able to unload any
1515 modules (note that some modules may not be unloadable
1516 anyway), which makes your kernel smaller, faster
1517 and simpler. If unsure, say Y.
1519 config MODULE_FORCE_UNLOAD
1520 bool "Forced module unloading"
1521 depends on MODULE_UNLOAD && EXPERIMENTAL
1523 This option allows you to force a module to unload, even if the
1524 kernel believes it is unsafe: the kernel will remove the module
1525 without waiting for anyone to stop using it (using the -f option to
1526 rmmod). This is mainly for kernel developers and desperate users.
1530 bool "Module versioning support"
1532 Usually, you have to use modules compiled with your kernel.
1533 Saying Y here makes it sometimes possible to use modules
1534 compiled for different kernels, by adding enough information
1535 to the modules to (hopefully) spot any changes which would
1536 make them incompatible with the kernel you are running. If
1539 config MODULE_SRCVERSION_ALL
1540 bool "Source checksum for all modules"
1542 Modules which contain a MODULE_VERSION get an extra "srcversion"
1543 field inserted into their modinfo section, which contains a
1544 sum of the source files which made it. This helps maintainers
1545 see exactly which source was used to build a module (since
1546 others sometimes change the module source without updating
1547 the version). With this option, such a "srcversion" field
1548 will be created for all modules. If unsure, say N.
1552 config INIT_ALL_POSSIBLE
1555 Back when each arch used to define their own cpu_online_map and
1556 cpu_possible_map, some of them chose to initialize cpu_possible_map
1557 with all 1s, and others with all 0s. When they were centralised,
1558 it was better to provide this option than to break all the archs
1559 and have several arch maintainers pursuing me down dark alleys.
1564 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1566 Need stop_machine() primitive.
1568 source "block/Kconfig"
1570 config PREEMPT_NOTIFIERS
1577 source "kernel/Kconfig.locks"