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"
22 bool "Prompt for development and/or incomplete code/drivers"
24 Some of the various things that Linux supports (such as network
25 drivers, file systems, network protocols, etc.) can be in a state
26 of development where the functionality, stability, or the level of
27 testing is not yet high enough for general use. This is usually
28 known as the "alpha-test" phase among developers. If a feature is
29 currently in alpha-test, then the developers usually discourage
30 uninformed widespread use of this feature by the general public to
31 avoid "Why doesn't this work?" type mail messages. However, active
32 testing and use of these systems is welcomed. Just be aware that it
33 may not meet the normal level of reliability or it may fail to work
34 in some special cases. Detailed bug reports from people familiar
35 with the kernel internals are usually welcomed by the developers
36 (before submitting bug reports, please read the documents
37 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
38 <file:Documentation/BUG-HUNTING>, and
39 <file:Documentation/oops-tracing.txt> in the kernel source).
41 This option will also make obsoleted drivers available. These are
42 drivers that have been replaced by something else, and/or are
43 scheduled to be removed in a future kernel release.
45 Unless you intend to help test and develop a feature or driver that
46 falls into this category, or you have a situation that requires
47 using these features, you should probably say N here, which will
48 cause the configurator to present you with fewer choices. If
49 you say Y here, you will be offered the choice of using features or
50 drivers that are currently considered to be in the alpha-test phase.
57 depends on BROKEN || !SMP
62 depends on SMP || PREEMPT
65 config INIT_ENV_ARG_LIMIT
70 Maximum of each of the number of arguments and environment
71 variables passed to init from the kernel command line.
75 string "Local version - append to kernel release"
77 Append an extra string to the end of your kernel version.
78 This will show up when you type uname, for example.
79 The string you set here will be appended after the contents of
80 any files with a filename matching localversion* in your
81 object and source tree, in that order. Your total string can
82 be a maximum of 64 characters.
84 config LOCALVERSION_AUTO
85 bool "Automatically append version information to the version string"
88 This will try to automatically determine if the current tree is a
89 release tree by looking for git tags that belong to the current
92 A string of the format -gxxxxxxxx will be added to the localversion
93 if a git-based tree is found. The string generated by this will be
94 appended after any matching localversion* files, and after the value
95 set in CONFIG_LOCALVERSION.
97 (The actual string used here is the first eight characters produced
98 by running the command:
100 $ git rev-parse --verify HEAD
102 which is done within the script "scripts/setlocalversion".)
104 config HAVE_KERNEL_GZIP
107 config HAVE_KERNEL_BZIP2
110 config HAVE_KERNEL_LZMA
114 prompt "Kernel compression mode"
116 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA
118 The linux kernel is a kind of self-extracting executable.
119 Several compression algorithms are available, which differ
120 in efficiency, compression and decompression speed.
121 Compression speed is only relevant when building a kernel.
122 Decompression speed is relevant at each boot.
124 If you have any problems with bzip2 or lzma compressed
125 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
126 version of this functionality (bzip2 only), for 2.4, was
127 supplied by Christian Ludwig)
129 High compression options are mostly useful for users, who
130 are low on disk space (embedded systems), but for whom ram
133 If in doubt, select 'gzip'
137 depends on HAVE_KERNEL_GZIP
139 The old and tried gzip compression. Its compression ratio is
140 the poorest among the 3 choices; however its speed (both
141 compression and decompression) is the fastest.
145 depends on HAVE_KERNEL_BZIP2
147 Its compression ratio and speed is intermediate.
148 Decompression speed is slowest among the three. The kernel
149 size is about 10% smaller with bzip2, in comparison to gzip.
150 Bzip2 uses a large amount of memory. For modern kernels you
151 will need at least 8MB RAM or more for booting.
155 depends on HAVE_KERNEL_LZMA
157 The most recent compression algorithm.
158 Its ratio is best, decompression speed is between the other
159 two. Compression is slowest. The kernel size is about 33%
160 smaller with LZMA in comparison to gzip.
165 bool "Support for paging of anonymous memory (swap)"
166 depends on MMU && BLOCK
169 This option allows you to choose whether you want to have support
170 for so called swap devices or swap files in your kernel that are
171 used to provide more virtual memory than the actual RAM present
172 in your computer. If unsure say Y.
177 Inter Process Communication is a suite of library functions and
178 system calls which let processes (running programs) synchronize and
179 exchange information. It is generally considered to be a good thing,
180 and some programs won't run unless you say Y here. In particular, if
181 you want to run the DOS emulator dosemu under Linux (read the
182 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
183 you'll need to say Y here.
185 You can find documentation about IPC with "info ipc" and also in
186 section 6.4 of the Linux Programmer's Guide, available from
187 <http://www.tldp.org/guides.html>.
189 config SYSVIPC_SYSCTL
196 bool "POSIX Message Queues"
197 depends on NET && EXPERIMENTAL
199 POSIX variant of message queues is a part of IPC. In POSIX message
200 queues every message has a priority which decides about succession
201 of receiving it by a process. If you want to compile and run
202 programs written e.g. for Solaris with use of its POSIX message
203 queues (functions mq_*) say Y here.
205 POSIX message queues are visible as a filesystem called 'mqueue'
206 and can be mounted somewhere if you want to do filesystem
207 operations on message queues.
211 config BSD_PROCESS_ACCT
212 bool "BSD Process Accounting"
214 If you say Y here, a user level program will be able to instruct the
215 kernel (via a special system call) to write process accounting
216 information to a file: whenever a process exits, information about
217 that process will be appended to the file by the kernel. The
218 information includes things such as creation time, owning user,
219 command name, memory usage, controlling terminal etc. (the complete
220 list is in the struct acct in <file:include/linux/acct.h>). It is
221 up to the user level program to do useful things with this
222 information. This is generally a good idea, so say Y.
224 config BSD_PROCESS_ACCT_V3
225 bool "BSD Process Accounting version 3 file format"
226 depends on BSD_PROCESS_ACCT
229 If you say Y here, the process accounting information is written
230 in a new file format that also logs the process IDs of each
231 process and it's parent. Note that this file format is incompatible
232 with previous v0/v1/v2 file formats, so you will need updated tools
233 for processing it. A preliminary version of these tools is available
234 at <http://www.gnu.org/software/acct/>.
237 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
241 Export selected statistics for tasks/processes through the
242 generic netlink interface. Unlike BSD process accounting, the
243 statistics are available during the lifetime of tasks/processes as
244 responses to commands. Like BSD accounting, they are sent to user
249 config TASK_DELAY_ACCT
250 bool "Enable per-task delay accounting (EXPERIMENTAL)"
253 Collect information on time spent by a task waiting for system
254 resources like cpu, synchronous block I/O completion and swapping
255 in pages. Such statistics can help in setting a task's priorities
256 relative to other tasks for cpu, io, rss limits etc.
261 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
264 Collect extended task accounting data and send the data
265 to userland for processing over the taskstats interface.
269 config TASK_IO_ACCOUNTING
270 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
271 depends on TASK_XACCT
273 Collect information on the number of bytes of storage I/O which this
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 || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
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,
294 such as SELinux. To use audit's filesystem watch feature, please
295 ensure that INOTIFY is configured.
299 depends on AUDITSYSCALL && INOTIFY
304 prompt "RCU Implementation"
310 This option selects the classic RCU implementation that is
311 designed for best read-side performance on non-realtime
314 Select this option if you are unsure.
317 bool "Tree-based hierarchical RCU"
319 This option selects the RCU implementation that is
320 designed for very large SMP system with hundreds or
324 bool "Preemptible RCU"
327 This option reduces the latency of the kernel by making certain
328 RCU sections preemptible. Normally RCU code is non-preemptible, if
329 this option is selected then read-only RCU sections become
330 preemptible. This helps latency, but may expose bugs due to
331 now-naive assumptions about each RCU read-side critical section
332 remaining on a given CPU through its execution.
337 bool "Enable tracing for RCU"
338 depends on TREE_RCU || PREEMPT_RCU
340 This option provides tracing in RCU which presents stats
341 in debugfs for debugging RCU implementation.
343 Say Y here if you want to enable RCU tracing
344 Say N if you are unsure.
347 int "Tree-based hierarchical RCU fanout value"
354 This option controls the fanout of hierarchical implementations
355 of RCU, allowing RCU to work efficiently on machines with
356 large numbers of CPUs. This value must be at least the cube
357 root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
358 systems and up to 262,144 for 64-bit systems.
360 Select a specific number if testing RCU itself.
361 Take the default if unsure.
363 config RCU_FANOUT_EXACT
364 bool "Disable tree-based hierarchical RCU auto-balancing"
368 This option forces use of the exact RCU_FANOUT value specified,
369 regardless of imbalances in the hierarchy. This is useful for
370 testing RCU itself, and might one day be useful on systems with
371 strong NUMA behavior.
373 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
377 config TREE_RCU_TRACE
378 def_bool RCU_TRACE && TREE_RCU
381 This option provides tracing for the TREE_RCU implementation,
382 permitting Makefile to trivially select kernel/rcutree_trace.c.
384 config PREEMPT_RCU_TRACE
385 def_bool RCU_TRACE && PREEMPT_RCU
388 This option provides tracing for the PREEMPT_RCU implementation,
389 permitting Makefile to trivially select kernel/rcupreempt_trace.c.
391 endmenu # "RCU Subsystem"
394 tristate "Kernel .config support"
396 This option enables the complete Linux kernel ".config" file
397 contents to be saved in the kernel. It provides documentation
398 of which kernel options are used in a running kernel or in an
399 on-disk kernel. This information can be extracted from the kernel
400 image file with the script scripts/extract-ikconfig and used as
401 input to rebuild the current kernel or to build another kernel.
402 It can also be extracted from a running kernel by reading
403 /proc/config.gz if enabled (below).
406 bool "Enable access to .config through /proc/config.gz"
407 depends on IKCONFIG && PROC_FS
409 This option enables access to the kernel configuration file
410 through /proc/config.gz.
413 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
417 Select kernel log buffer size as a power of 2.
427 # Architectures with an unreliable sched_clock() should select this:
429 config HAVE_UNSTABLE_SCHED_CLOCK
433 bool "Group CPU scheduler"
434 depends on EXPERIMENTAL
437 This feature lets CPU scheduler recognize task groups and control CPU
438 bandwidth allocation to such task groups.
439 In order to create a group from arbitrary set of processes, use
440 CONFIG_CGROUPS. (See Control Group support.)
442 config FAIR_GROUP_SCHED
443 bool "Group scheduling for SCHED_OTHER"
444 depends on GROUP_SCHED
447 config RT_GROUP_SCHED
448 bool "Group scheduling for SCHED_RR/FIFO"
449 depends on EXPERIMENTAL
450 depends on GROUP_SCHED
453 This feature lets you explicitly allocate real CPU bandwidth
454 to users or control groups (depending on the "Basis for grouping tasks"
455 setting below. If enabled, it will also make it impossible to
456 schedule realtime tasks for non-root users until you allocate
457 realtime bandwidth for them.
458 See Documentation/scheduler/sched-rt-group.txt for more information.
461 depends on GROUP_SCHED
462 prompt "Basis for grouping tasks"
468 This option will choose userid as the basis for grouping
469 tasks, thus providing equal CPU bandwidth to each user.
472 bool "Control groups"
475 This option allows you to create arbitrary task groups
476 using the "cgroup" pseudo filesystem and control
477 the cpu bandwidth allocated to each such task group.
478 Refer to Documentation/cgroups/cgroups.txt for more
479 information on "cgroup" pseudo filesystem.
484 boolean "Control Group support"
486 This option adds support for grouping sets of processes together, for
487 use with process control subsystems such as Cpusets, CFS, memory
488 controls or device isolation.
490 - Documentation/scheduler/sched-design-CFS.txt (CFS)
491 - Documentation/cgroups/ (features for grouping, isolation
492 and resource control)
499 bool "Example debug cgroup subsystem"
503 This option enables a simple cgroup subsystem that
504 exports useful debugging information about the cgroups
510 bool "Namespace cgroup subsystem"
513 Provides a simple namespace cgroup subsystem to
514 provide hierarchical naming of sets of namespaces,
515 for instance virtual servers and checkpoint/restart
518 config CGROUP_FREEZER
519 bool "Freezer cgroup subsystem"
522 Provides a way to freeze and unfreeze all tasks in a
526 bool "Device controller for cgroups"
527 depends on CGROUPS && EXPERIMENTAL
529 Provides a cgroup implementing whitelists for devices which
530 a process in the cgroup can mknod or open.
533 bool "Cpuset support"
536 This option will let you create and manage CPUSETs which
537 allow dynamically partitioning a system into sets of CPUs and
538 Memory Nodes and assigning tasks to run only within those sets.
539 This is primarily useful on large SMP or NUMA systems.
543 config PROC_PID_CPUSET
544 bool "Include legacy /proc/<pid>/cpuset file"
548 config CGROUP_CPUACCT
549 bool "Simple CPU accounting cgroup subsystem"
552 Provides a simple Resource Controller for monitoring the
553 total CPU consumed by the tasks in a cgroup.
555 config RESOURCE_COUNTERS
556 bool "Resource counters"
558 This option enables controller independent resource accounting
559 infrastructure that works with cgroups.
562 config CGROUP_MEM_RES_CTLR
563 bool "Memory Resource Controller for Control Groups"
564 depends on CGROUPS && RESOURCE_COUNTERS
567 Provides a memory resource controller that manages both anonymous
568 memory and page cache. (See Documentation/controllers/memory.txt)
570 Note that setting this option increases fixed memory overhead
571 associated with each page of memory in the system. By this,
572 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
573 usage tracking struct at boot. Total amount of this is printed out
576 Only enable when you're ok with these trade offs and really
577 sure you need the memory resource controller. Even when you enable
578 this, you can set "cgroup_disable=memory" at your boot option to
579 disable memory resource controller and you can avoid overheads.
580 (and lose benefits of memory resource controller)
582 This config option also selects MM_OWNER config option, which
583 could in turn add some fork/exit overhead.
585 config CGROUP_MEM_RES_CTLR_SWAP
586 bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)"
587 depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL
589 Add swap management feature to memory resource controller. When you
590 enable this, you can limit mem+swap usage per cgroup. In other words,
591 when you disable this, memory resource controller has no cares to
592 usage of swap...a process can exhaust all of the swap. This extension
593 is useful when you want to avoid exhaustion swap but this itself
594 adds more overheads and consumes memory for remembering information.
595 Especially if you use 32bit system or small memory system, please
596 be careful about enabling this. When memory resource controller
597 is disabled by boot option, this will be automatically disabled and
598 there will be no overhead from this. Even when you set this config=y,
599 if boot option "noswapaccount" is set, swap will not be accounted.
600 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
601 size is 4096bytes, 512k per 1Gbytes of swap.
608 config SYSFS_DEPRECATED
611 config SYSFS_DEPRECATED_V2
612 bool "Create deprecated sysfs layout for older userspace tools"
615 select SYSFS_DEPRECATED
617 This option switches the layout of sysfs to the deprecated
620 The current sysfs layout features a unified device tree at
621 /sys/devices/, which is able to express a hierarchy between
622 class devices. If the deprecated option is set to Y, the
623 unified device tree is split into a bus device tree at
624 /sys/devices/ and several individual class device trees at
625 /sys/class/. The class and bus devices will be connected by
626 "<subsystem>:<name>" and the "device" links. The "block"
627 class devices, will not show up in /sys/class/block/. Some
628 subsystems will suppress the creation of some devices which
629 depend on the unified device tree.
631 This option is not a pure compatibility option that can
632 be safely enabled on newer distributions. It will change the
633 layout of sysfs to the non-extensible deprecated version,
634 and disable some features, which can not be exported without
635 confusing older userspace tools. Since 2007/2008 all major
636 distributions do not enable this option, and ship no tools which
637 depend on the deprecated layout or this option.
639 If you are using a new kernel on an older distribution, or use
640 older userspace tools, you might need to say Y here. Do not say Y,
641 if the original kernel, that came with your distribution, has
642 this option set to N.
645 bool "Kernel->user space relay support (formerly relayfs)"
647 This option enables support for relay interface support in
648 certain file systems (such as debugfs).
649 It is designed to provide an efficient mechanism for tools and
650 facilities to relay large amounts of data from kernel space to
656 bool "Namespaces support" if EMBEDDED
659 Provides the way to make tasks work with different objects using
660 the same id. For example same IPC id may refer to different objects
661 or same user id or pid may refer to different tasks when used in
662 different namespaces.
666 depends on NAMESPACES
668 In this namespace tasks see different info provided with the
673 depends on NAMESPACES && SYSVIPC
675 In this namespace tasks work with IPC ids which correspond to
676 different IPC objects in different namespaces
679 bool "User namespace (EXPERIMENTAL)"
680 depends on NAMESPACES && EXPERIMENTAL
682 This allows containers, i.e. vservers, to use user namespaces
683 to provide different user info for different servers.
687 bool "PID Namespaces (EXPERIMENTAL)"
689 depends on NAMESPACES && EXPERIMENTAL
691 Support process id namespaces. This allows having multiple
692 process with the same pid as long as they are in different
693 pid namespaces. This is a building block of containers.
695 Unless you want to work with an experimental feature
699 bool "Network namespace"
701 depends on NAMESPACES && EXPERIMENTAL && NET
703 Allow user space to create what appear to be multiple instances
704 of the network stack.
706 config BLK_DEV_INITRD
707 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
708 depends on BROKEN || !FRV
710 The initial RAM filesystem is a ramfs which is loaded by the
711 boot loader (loadlin or lilo) and that is mounted as root
712 before the normal boot procedure. It is typically used to
713 load modules needed to mount the "real" root file system,
714 etc. See <file:Documentation/initrd.txt> for details.
716 If RAM disk support (BLK_DEV_RAM) is also included, this
717 also enables initial RAM disk (initrd) support and adds
718 15 Kbytes (more on some other architectures) to the kernel size.
728 config CC_OPTIMIZE_FOR_SIZE
729 bool "Optimize for size"
732 Enabling this option will pass "-Os" instead of "-O2" to gcc
733 resulting in a smaller kernel.
744 bool "Configure standard kernel features (for small systems)"
746 This option allows certain base kernel options and settings
747 to be disabled or tweaked. This is for specialized
748 environments which can tolerate a "non-standard" kernel.
749 Only use this if you really know what you are doing.
752 bool "Enable 16-bit UID system calls" if EMBEDDED
753 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
756 This enables the legacy 16-bit UID syscall wrappers.
758 config SYSCTL_SYSCALL
759 bool "Sysctl syscall support" if EMBEDDED
763 sys_sysctl uses binary paths that have been found challenging
764 to properly maintain and use. The interface in /proc/sys
765 using paths with ascii names is now the primary path to this
768 Almost nothing using the binary sysctl interface so if you are
769 trying to save some space it is probably safe to disable this,
770 making your kernel marginally smaller.
772 If unsure say Y here.
775 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
778 Say Y here to let the kernel print out symbolic crash information and
779 symbolic stack backtraces. This increases the size of the kernel
780 somewhat, as all symbols have to be loaded into the kernel image.
783 bool "Include all symbols in kallsyms"
784 depends on DEBUG_KERNEL && KALLSYMS
786 Normally kallsyms only contains the symbols of functions, for nicer
787 OOPS messages. Some debuggers can use kallsyms for other
788 symbols too: say Y here to include all symbols, if you need them
789 and you don't care about adding 300k to the size of your kernel.
793 config KALLSYMS_EXTRA_PASS
794 bool "Do an extra kallsyms pass"
797 If kallsyms is not working correctly, the build will fail with
798 inconsistent kallsyms data. If that occurs, log a bug report and
799 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
800 Always say N here unless you find a bug in kallsyms, which must be
801 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
802 you wait for kallsyms to be fixed.
806 bool "Support for hot-pluggable devices" if EMBEDDED
809 This option is provided for the case where no hotplug or uevent
810 capabilities is wanted by the kernel. You should only consider
811 disabling this option for embedded systems that do not use modules, a
812 dynamic /dev tree, or dynamic device discovery. Just say Y.
816 bool "Enable support for printk" if EMBEDDED
818 This option enables normal printk support. Removing it
819 eliminates most of the message strings from the kernel image
820 and makes the kernel more or less silent. As this makes it
821 very difficult to diagnose system problems, saying N here is
822 strongly discouraged.
825 bool "BUG() support" if EMBEDDED
828 Disabling this option eliminates support for BUG and WARN, reducing
829 the size of your kernel image and potentially quietly ignoring
830 numerous fatal conditions. You should only consider disabling this
831 option for embedded systems with no facilities for reporting errors.
836 bool "Enable ELF core dumps" if EMBEDDED
838 Enable support for generating core dumps. Disabling saves about 4k.
840 config PCSPKR_PLATFORM
841 bool "Enable PC-Speaker support" if EMBEDDED
842 depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
845 This option allows to disable the internal PC-Speaker
846 support, saving some memory.
850 bool "Enable full-sized data structures for core" if EMBEDDED
852 Disabling this option reduces the size of miscellaneous core
853 kernel data structures. This saves memory on small machines,
854 but may reduce performance.
857 bool "Enable futex support" if EMBEDDED
861 Disabling this option will cause the kernel to be built without
862 support for "fast userspace mutexes". The resulting kernel may not
863 run glibc-based applications correctly.
866 bool "Enable eventpoll support" if EMBEDDED
870 Disabling this option will cause the kernel to be built without
871 support for epoll family of system calls.
874 bool "Enable signalfd() system call" if EMBEDDED
878 Enable the signalfd() system call that allows to receive signals
879 on a file descriptor.
884 bool "Enable timerfd() system call" if EMBEDDED
888 Enable the timerfd() system call that allows to receive timer
889 events on a file descriptor.
894 bool "Enable eventfd() system call" if EMBEDDED
898 Enable the eventfd() system call that allows to receive both
899 kernel notification (ie. KAIO) or userspace notifications.
904 bool "Use full shmem filesystem" if EMBEDDED
908 The shmem is an internal filesystem used to manage shared memory.
909 It is backed by swap and manages resource limits. It is also exported
910 to userspace as tmpfs if TMPFS is enabled. Disabling this
911 option replaces shmem and tmpfs with the much simpler ramfs code,
912 which may be appropriate on small systems without swap.
915 bool "Enable AIO support" if EMBEDDED
918 This option enables POSIX asynchronous I/O which may by used
919 by some high performance threaded applications. Disabling
920 this option saves about 7k.
922 config VM_EVENT_COUNTERS
924 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
926 VM event counters are needed for event counts to be shown.
927 This option allows the disabling of the VM event counters
928 on EMBEDDED systems. /proc/vmstat will only show page counts
929 if VM event counters are disabled.
933 bool "Enable PCI quirk workarounds" if EMBEDDED
936 This enables workarounds for various PCI chipset
937 bugs/quirks. Disable this only if your target machine is
938 unaffected by PCI quirks.
942 bool "Enable SLUB debugging support" if EMBEDDED
943 depends on SLUB && SYSFS
945 SLUB has extensive debug support features. Disabling these can
946 result in significant savings in code size. This also disables
947 SLUB sysfs support. /sys/slab will not exist and there will be
948 no support for cache validation etc.
951 bool "Disable heap randomization"
954 Randomizing heap placement makes heap exploits harder, but it
955 also breaks ancient binaries (including anything libc5 based).
956 This option changes the bootup default to heap randomization
957 disabled, and can be overriden runtime by setting
958 /proc/sys/kernel/randomize_va_space to 2.
960 On non-ancient distros (post-2000 ones) N is usually a safe choice.
963 prompt "Choose SLAB allocator"
966 This option allows to select a slab allocator.
971 The regular slab allocator that is established and known to work
972 well in all environments. It organizes cache hot objects in
973 per cpu and per node queues.
976 bool "SLUB (Unqueued Allocator)"
978 SLUB is a slab allocator that minimizes cache line usage
979 instead of managing queues of cached objects (SLAB approach).
980 Per cpu caching is realized using slabs of objects instead
981 of queues of objects. SLUB can use memory efficiently
982 and has enhanced diagnostics. SLUB is the default choice for
987 bool "SLOB (Simple Allocator)"
989 SLOB replaces the stock allocator with a drastically simpler
990 allocator. SLOB is generally more space efficient but
991 does not perform as well on large systems.
996 bool "Profiling support (EXPERIMENTAL)"
998 Say Y here to enable the extended profiling support mechanisms used
999 by profilers such as OProfile.
1002 # Place an empty function call at each tracepoint site. Can be
1003 # dynamically changed for a probe function.
1009 bool "Activate markers"
1010 depends on TRACEPOINTS
1012 Place an empty function call at each marker site. Can be
1013 dynamically changed for a probe function.
1015 source "arch/Kconfig"
1017 endmenu # General setup
1019 config HAVE_GENERIC_DMA_COHERENT
1026 depends on SLAB || SLUB_DEBUG
1034 default 0 if BASE_FULL
1035 default 1 if !BASE_FULL
1038 bool "Enable loadable module support"
1040 Kernel modules are small pieces of compiled code which can
1041 be inserted in the running kernel, rather than being
1042 permanently built into the kernel. You use the "modprobe"
1043 tool to add (and sometimes remove) them. If you say Y here,
1044 many parts of the kernel can be built as modules (by
1045 answering M instead of Y where indicated): this is most
1046 useful for infrequently used options which are not required
1047 for booting. For more information, see the man pages for
1048 modprobe, lsmod, modinfo, insmod and rmmod.
1050 If you say Y here, you will need to run "make
1051 modules_install" to put the modules under /lib/modules/
1052 where modprobe can find them (you may need to be root to do
1059 config MODULE_FORCE_LOAD
1060 bool "Forced module loading"
1063 Allow loading of modules without version information (ie. modprobe
1064 --force). Forced module loading sets the 'F' (forced) taint flag and
1065 is usually a really bad idea.
1067 config MODULE_UNLOAD
1068 bool "Module unloading"
1070 Without this option you will not be able to unload any
1071 modules (note that some modules may not be unloadable
1072 anyway), which makes your kernel smaller, faster
1073 and simpler. If unsure, say Y.
1075 config MODULE_FORCE_UNLOAD
1076 bool "Forced module unloading"
1077 depends on MODULE_UNLOAD && EXPERIMENTAL
1079 This option allows you to force a module to unload, even if the
1080 kernel believes it is unsafe: the kernel will remove the module
1081 without waiting for anyone to stop using it (using the -f option to
1082 rmmod). This is mainly for kernel developers and desperate users.
1086 bool "Module versioning support"
1088 Usually, you have to use modules compiled with your kernel.
1089 Saying Y here makes it sometimes possible to use modules
1090 compiled for different kernels, by adding enough information
1091 to the modules to (hopefully) spot any changes which would
1092 make them incompatible with the kernel you are running. If
1095 config MODULE_SRCVERSION_ALL
1096 bool "Source checksum for all modules"
1098 Modules which contain a MODULE_VERSION get an extra "srcversion"
1099 field inserted into their modinfo section, which contains a
1100 sum of the source files which made it. This helps maintainers
1101 see exactly which source was used to build a module (since
1102 others sometimes change the module source without updating
1103 the version). With this option, such a "srcversion" field
1104 will be created for all modules. If unsure, say N.
1108 config INIT_ALL_POSSIBLE
1111 Back when each arch used to define their own cpu_online_map and
1112 cpu_possible_map, some of them chose to initialize cpu_possible_map
1113 with all 1s, and others with all 0s. When they were centralised,
1114 it was better to provide this option than to break all the archs
1115 and have several arch maintainers persuing me down dark alleys.
1120 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1122 Need stop_machine() primitive.
1124 source "block/Kconfig"
1126 config PREEMPT_NOTIFIERS
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