x86: Exit RCU extended QS on notify resume
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / init / Kconfig
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1config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
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9config DEFCONFIG_LIST
10 string
b2670eac 11 depends on !UML
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12 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
73531905 16 default "$ARCH_DEFCONFIG"
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17 default "arch/$ARCH/defconfig"
18
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19config CONSTRUCTORS
20 bool
21 depends on !UML
b99b87f7 22
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23config HAVE_IRQ_WORK
24 bool
25
26config IRQ_WORK
27 bool
28 depends on HAVE_IRQ_WORK
29
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30config BUILDTIME_EXTABLE_SORT
31 bool
32
ff0cfc66 33menu "General setup"
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34
35config EXPERIMENTAL
36 bool "Prompt for development and/or incomplete code/drivers"
37 ---help---
38 Some of the various things that Linux supports (such as network
39 drivers, file systems, network protocols, etc.) can be in a state
40 of development where the functionality, stability, or the level of
41 testing is not yet high enough for general use. This is usually
42 known as the "alpha-test" phase among developers. If a feature is
43 currently in alpha-test, then the developers usually discourage
44 uninformed widespread use of this feature by the general public to
45 avoid "Why doesn't this work?" type mail messages. However, active
46 testing and use of these systems is welcomed. Just be aware that it
47 may not meet the normal level of reliability or it may fail to work
48 in some special cases. Detailed bug reports from people familiar
49 with the kernel internals are usually welcomed by the developers
50 (before submitting bug reports, please read the documents
51 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
52 <file:Documentation/BUG-HUNTING>, and
53 <file:Documentation/oops-tracing.txt> in the kernel source).
54
55 This option will also make obsoleted drivers available. These are
56 drivers that have been replaced by something else, and/or are
57 scheduled to be removed in a future kernel release.
58
59 Unless you intend to help test and develop a feature or driver that
60 falls into this category, or you have a situation that requires
61 using these features, you should probably say N here, which will
62 cause the configurator to present you with fewer choices. If
63 you say Y here, you will be offered the choice of using features or
64 drivers that are currently considered to be in the alpha-test phase.
65
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66config BROKEN
67 bool
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68
69config BROKEN_ON_SMP
70 bool
71 depends on BROKEN || !SMP
72 default y
73
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74config INIT_ENV_ARG_LIMIT
75 int
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76 default 32 if !UML
77 default 128 if UML
1da177e4 78 help
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79 Maximum of each of the number of arguments and environment
80 variables passed to init from the kernel command line.
1da177e4 81
1da177e4 82
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83config CROSS_COMPILE
84 string "Cross-compiler tool prefix"
85 help
86 Same as running 'make CROSS_COMPILE=prefix-' but stored for
87 default make runs in this kernel build directory. You don't
88 need to set this unless you want the configured kernel build
89 directory to select the cross-compiler automatically.
90
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91config LOCALVERSION
92 string "Local version - append to kernel release"
93 help
94 Append an extra string to the end of your kernel version.
95 This will show up when you type uname, for example.
96 The string you set here will be appended after the contents of
97 any files with a filename matching localversion* in your
98 object and source tree, in that order. Your total string can
99 be a maximum of 64 characters.
100
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101config LOCALVERSION_AUTO
102 bool "Automatically append version information to the version string"
103 default y
104 help
105 This will try to automatically determine if the current tree is a
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106 release tree by looking for git tags that belong to the current
107 top of tree revision.
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108
109 A string of the format -gxxxxxxxx will be added to the localversion
6e5a5420 110 if a git-based tree is found. The string generated by this will be
aaebf433 111 appended after any matching localversion* files, and after the value
6e5a5420 112 set in CONFIG_LOCALVERSION.
aaebf433 113
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114 (The actual string used here is the first eight characters produced
115 by running the command:
116
117 $ git rev-parse --verify HEAD
118
119 which is done within the script "scripts/setlocalversion".)
aaebf433 120
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121config HAVE_KERNEL_GZIP
122 bool
123
124config HAVE_KERNEL_BZIP2
125 bool
126
127config HAVE_KERNEL_LZMA
128 bool
129
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130config HAVE_KERNEL_XZ
131 bool
132
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133config HAVE_KERNEL_LZO
134 bool
135
30d65dbf 136choice
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137 prompt "Kernel compression mode"
138 default KERNEL_GZIP
3ebe1243 139 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
2e9f3bdd 140 help
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141 The linux kernel is a kind of self-extracting executable.
142 Several compression algorithms are available, which differ
143 in efficiency, compression and decompression speed.
144 Compression speed is only relevant when building a kernel.
145 Decompression speed is relevant at each boot.
146
147 If you have any problems with bzip2 or lzma compressed
148 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
149 version of this functionality (bzip2 only), for 2.4, was
150 supplied by Christian Ludwig)
151
152 High compression options are mostly useful for users, who
153 are low on disk space (embedded systems), but for whom ram
154 size matters less.
155
156 If in doubt, select 'gzip'
157
158config KERNEL_GZIP
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159 bool "Gzip"
160 depends on HAVE_KERNEL_GZIP
161 help
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162 The old and tried gzip compression. It provides a good balance
163 between compression ratio and decompression speed.
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164
165config KERNEL_BZIP2
166 bool "Bzip2"
2e9f3bdd 167 depends on HAVE_KERNEL_BZIP2
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168 help
169 Its compression ratio and speed is intermediate.
0a4dd35c 170 Decompression speed is slowest among the choices. The kernel
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171 size is about 10% smaller with bzip2, in comparison to gzip.
172 Bzip2 uses a large amount of memory. For modern kernels you
173 will need at least 8MB RAM or more for booting.
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174
175config KERNEL_LZMA
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176 bool "LZMA"
177 depends on HAVE_KERNEL_LZMA
178 help
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179 This compression algorithm's ratio is best. Decompression speed
180 is between gzip and bzip2. Compression is slowest.
181 The kernel size is about 33% smaller with LZMA in comparison to gzip.
30d65dbf 182
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183config KERNEL_XZ
184 bool "XZ"
185 depends on HAVE_KERNEL_XZ
186 help
187 XZ uses the LZMA2 algorithm and instruction set specific
188 BCJ filters which can improve compression ratio of executable
189 code. The size of the kernel is about 30% smaller with XZ in
190 comparison to gzip. On architectures for which there is a BCJ
191 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
192 will create a few percent smaller kernel than plain LZMA.
193
194 The speed is about the same as with LZMA: The decompression
195 speed of XZ is better than that of bzip2 but worse than gzip
196 and LZO. Compression is slow.
197
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198config KERNEL_LZO
199 bool "LZO"
200 depends on HAVE_KERNEL_LZO
201 help
0a4dd35c 202 Its compression ratio is the poorest among the choices. The kernel
681b3049 203 size is about 10% bigger than gzip; however its speed
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204 (both compression and decompression) is the fastest.
205
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206endchoice
207
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208config DEFAULT_HOSTNAME
209 string "Default hostname"
210 default "(none)"
211 help
212 This option determines the default system hostname before userspace
213 calls sethostname(2). The kernel traditionally uses "(none)" here,
214 but you may wish to use a different default here to make a minimal
215 system more usable with less configuration.
216
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217config SWAP
218 bool "Support for paging of anonymous memory (swap)"
9361401e 219 depends on MMU && BLOCK
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220 default y
221 help
222 This option allows you to choose whether you want to have support
92c3504e 223 for so called swap devices or swap files in your kernel that are
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224 used to provide more virtual memory than the actual RAM present
225 in your computer. If unsure say Y.
226
227config SYSVIPC
228 bool "System V IPC"
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229 ---help---
230 Inter Process Communication is a suite of library functions and
231 system calls which let processes (running programs) synchronize and
232 exchange information. It is generally considered to be a good thing,
233 and some programs won't run unless you say Y here. In particular, if
234 you want to run the DOS emulator dosemu under Linux (read the
235 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
236 you'll need to say Y here.
237
238 You can find documentation about IPC with "info ipc" and also in
239 section 6.4 of the Linux Programmer's Guide, available from
240 <http://www.tldp.org/guides.html>.
241
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242config SYSVIPC_SYSCTL
243 bool
244 depends on SYSVIPC
245 depends on SYSCTL
246 default y
247
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248config POSIX_MQUEUE
249 bool "POSIX Message Queues"
250 depends on NET && EXPERIMENTAL
251 ---help---
252 POSIX variant of message queues is a part of IPC. In POSIX message
253 queues every message has a priority which decides about succession
254 of receiving it by a process. If you want to compile and run
255 programs written e.g. for Solaris with use of its POSIX message
b0e37650 256 queues (functions mq_*) say Y here.
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257
258 POSIX message queues are visible as a filesystem called 'mqueue'
259 and can be mounted somewhere if you want to do filesystem
260 operations on message queues.
261
262 If unsure, say Y.
263
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264config POSIX_MQUEUE_SYSCTL
265 bool
266 depends on POSIX_MQUEUE
267 depends on SYSCTL
268 default y
269
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270config BSD_PROCESS_ACCT
271 bool "BSD Process Accounting"
272 help
273 If you say Y here, a user level program will be able to instruct the
274 kernel (via a special system call) to write process accounting
275 information to a file: whenever a process exits, information about
276 that process will be appended to the file by the kernel. The
277 information includes things such as creation time, owning user,
278 command name, memory usage, controlling terminal etc. (the complete
279 list is in the struct acct in <file:include/linux/acct.h>). It is
280 up to the user level program to do useful things with this
281 information. This is generally a good idea, so say Y.
282
283config BSD_PROCESS_ACCT_V3
284 bool "BSD Process Accounting version 3 file format"
285 depends on BSD_PROCESS_ACCT
286 default n
287 help
288 If you say Y here, the process accounting information is written
289 in a new file format that also logs the process IDs of each
290 process and it's parent. Note that this file format is incompatible
291 with previous v0/v1/v2 file formats, so you will need updated tools
292 for processing it. A preliminary version of these tools is available
37a4c940 293 at <http://www.gnu.org/software/acct/>.
1da177e4 294
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295config FHANDLE
296 bool "open by fhandle syscalls"
297 select EXPORTFS
298 help
299 If you say Y here, a user level program will be able to map
300 file names to handle and then later use the handle for
301 different file system operations. This is useful in implementing
302 userspace file servers, which now track files using handles instead
303 of names. The handle would remain the same even if file names
304 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
305 syscalls.
306
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307config TASKSTATS
308 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
309 depends on NET
310 default n
311 help
312 Export selected statistics for tasks/processes through the
313 generic netlink interface. Unlike BSD process accounting, the
314 statistics are available during the lifetime of tasks/processes as
315 responses to commands. Like BSD accounting, they are sent to user
316 space on task exit.
317
318 Say N if unsure.
319
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320config TASK_DELAY_ACCT
321 bool "Enable per-task delay accounting (EXPERIMENTAL)"
6f44993f 322 depends on TASKSTATS
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323 help
324 Collect information on time spent by a task waiting for system
325 resources like cpu, synchronous block I/O completion and swapping
326 in pages. Such statistics can help in setting a task's priorities
327 relative to other tasks for cpu, io, rss limits etc.
328
329 Say N if unsure.
330
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331config TASK_XACCT
332 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
333 depends on TASKSTATS
334 help
335 Collect extended task accounting data and send the data
336 to userland for processing over the taskstats interface.
337
338 Say N if unsure.
339
340config TASK_IO_ACCOUNTING
341 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
342 depends on TASK_XACCT
343 help
344 Collect information on the number of bytes of storage I/O which this
345 task has caused.
346
347 Say N if unsure.
348
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349config AUDIT
350 bool "Auditing support"
804a6a49 351 depends on NET
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352 help
353 Enable auditing infrastructure that can be used with another
354 kernel subsystem, such as SELinux (which requires this for
355 logging of avc messages output). Does not do system-call
356 auditing without CONFIG_AUDITSYSCALL.
357
358config AUDITSYSCALL
359 bool "Enable system-call auditing support"
8f827a14 360 depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT))
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361 default y if SECURITY_SELINUX
362 help
363 Enable low-overhead system-call auditing infrastructure that
364 can be used independently or with another kernel subsystem,
67640b60 365 such as SELinux.
1da177e4 366
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367config AUDIT_WATCH
368 def_bool y
369 depends on AUDITSYSCALL
370 select FSNOTIFY
1da177e4 371
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372config AUDIT_TREE
373 def_bool y
63c882a0 374 depends on AUDITSYSCALL
28a3a7eb 375 select FSNOTIFY
74c3cbe3 376
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377config AUDIT_LOGINUID_IMMUTABLE
378 bool "Make audit loginuid immutable"
379 depends on AUDIT
380 help
f429ee3b 381 The config option toggles if a task setting its loginuid requires
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382 CAP_SYS_AUDITCONTROL or if that task should require no special permissions
383 but should instead only allow setting its loginuid if it was never
384 previously set. On systems which use systemd or a similar central
385 process to restart login services this should be set to true. On older
386 systems in which an admin would typically have to directly stop and
387 start processes this should be set to false. Setting this to true allows
388 one to drop potentially dangerous capabilites from the login tasks,
389 but may not be backwards compatible with older init systems.
390
d9817ebe 391source "kernel/irq/Kconfig"
764e0da1 392source "kernel/time/Kconfig"
d9817ebe 393
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394menu "RCU Subsystem"
395
396choice
397 prompt "RCU Implementation"
31c9a24e 398 default TREE_RCU
c903ff83 399
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400config TREE_RCU
401 bool "Tree-based hierarchical RCU"
687d7a96 402 depends on !PREEMPT && SMP
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403 help
404 This option selects the RCU implementation that is
405 designed for very large SMP system with hundreds or
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406 thousands of CPUs. It also scales down nicely to
407 smaller systems.
c903ff83 408
f41d911f 409config TREE_PREEMPT_RCU
a57eb940 410 bool "Preemptible tree-based hierarchical RCU"
8008e129 411 depends on PREEMPT && SMP
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412 help
413 This option selects the RCU implementation that is
414 designed for very large SMP systems with hundreds or
415 thousands of CPUs, but for which real-time response
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416 is also required. It also scales down nicely to
417 smaller systems.
f41d911f 418
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419config TINY_RCU
420 bool "UP-only small-memory-footprint RCU"
8008e129 421 depends on !PREEMPT && !SMP
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422 help
423 This option selects the RCU implementation that is
424 designed for UP systems from which real-time response
425 is not required. This option greatly reduces the
426 memory footprint of RCU.
427
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428config TINY_PREEMPT_RCU
429 bool "Preemptible UP-only small-memory-footprint RCU"
8008e129 430 depends on PREEMPT && !SMP
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431 help
432 This option selects the RCU implementation that is designed
433 for real-time UP systems. This option greatly reduces the
434 memory footprint of RCU.
435
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436endchoice
437
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438config PREEMPT_RCU
439 def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
440 help
441 This option enables preemptible-RCU code that is common between
442 the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
443
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444config RCU_USER_QS
445 bool "Consider userspace as in RCU extended quiescent state"
446 depends on HAVE_RCU_USER_QS && SMP
447 help
448 This option sets hooks on kernel / userspace boundaries and
449 puts RCU in extended quiescent state when the CPU runs in
450 userspace. It means that when a CPU runs in userspace, it is
451 excluded from the global RCU state machine and thus doesn't
452 to keep the timer tick on for RCU.
453
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454config RCU_FANOUT
455 int "Tree-based hierarchical RCU fanout value"
456 range 2 64 if 64BIT
457 range 2 32 if !64BIT
f41d911f 458 depends on TREE_RCU || TREE_PREEMPT_RCU
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459 default 64 if 64BIT
460 default 32 if !64BIT
461 help
462 This option controls the fanout of hierarchical implementations
463 of RCU, allowing RCU to work efficiently on machines with
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464 large numbers of CPUs. This value must be at least the fourth
465 root of NR_CPUS, which allows NR_CPUS to be insanely large.
466 The default value of RCU_FANOUT should be used for production
467 systems, but if you are stress-testing the RCU implementation
468 itself, small RCU_FANOUT values allow you to test large-system
469 code paths on small(er) systems.
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470
471 Select a specific number if testing RCU itself.
472 Take the default if unsure.
473
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474config RCU_FANOUT_LEAF
475 int "Tree-based hierarchical RCU leaf-level fanout value"
476 range 2 RCU_FANOUT if 64BIT
477 range 2 RCU_FANOUT if !64BIT
478 depends on TREE_RCU || TREE_PREEMPT_RCU
479 default 16
480 help
481 This option controls the leaf-level fanout of hierarchical
482 implementations of RCU, and allows trading off cache misses
483 against lock contention. Systems that synchronize their
484 scheduling-clock interrupts for energy-efficiency reasons will
485 want the default because the smaller leaf-level fanout keeps
486 lock contention levels acceptably low. Very large systems
487 (hundreds or thousands of CPUs) will instead want to set this
488 value to the maximum value possible in order to reduce the
489 number of cache misses incurred during RCU's grace-period
490 initialization. These systems tend to run CPU-bound, and thus
491 are not helped by synchronized interrupts, and thus tend to
492 skew them, which reduces lock contention enough that large
493 leaf-level fanouts work well.
494
495 Select a specific number if testing RCU itself.
496
497 Select the maximum permissible value for large systems.
498
499 Take the default if unsure.
500
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501config RCU_FANOUT_EXACT
502 bool "Disable tree-based hierarchical RCU auto-balancing"
f41d911f 503 depends on TREE_RCU || TREE_PREEMPT_RCU
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504 default n
505 help
506 This option forces use of the exact RCU_FANOUT value specified,
507 regardless of imbalances in the hierarchy. This is useful for
508 testing RCU itself, and might one day be useful on systems with
509 strong NUMA behavior.
510
511 Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
512
513 Say N if unsure.
514
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515config RCU_FAST_NO_HZ
516 bool "Accelerate last non-dyntick-idle CPU's grace periods"
b807fbff 517 depends on NO_HZ && SMP
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518 default n
519 help
520 This option causes RCU to attempt to accelerate grace periods
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521 in order to allow CPUs to enter dynticks-idle state more
522 quickly. On the other hand, this option increases the overhead
523 of the dynticks-idle checking, particularly on systems with
524 large numbers of CPUs.
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525
526 Say Y if energy efficiency is critically important, particularly
527 if you have relatively few CPUs.
528
529 Say N if you are unsure.
530
c903ff83 531config TREE_RCU_TRACE
f41d911f 532 def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
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533 select DEBUG_FS
534 help
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535 This option provides tracing for the TREE_RCU and
536 TREE_PREEMPT_RCU implementations, permitting Makefile to
537 trivially select kernel/rcutree_trace.c.
c903ff83 538
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539config RCU_BOOST
540 bool "Enable RCU priority boosting"
27f4d280 541 depends on RT_MUTEXES && PREEMPT_RCU
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542 default n
543 help
544 This option boosts the priority of preempted RCU readers that
545 block the current preemptible RCU grace period for too long.
546 This option also prevents heavy loads from blocking RCU
547 callback invocation for all flavors of RCU.
548
549 Say Y here if you are working with real-time apps or heavy loads
550 Say N here if you are unsure.
551
552config RCU_BOOST_PRIO
553 int "Real-time priority to boost RCU readers to"
554 range 1 99
555 depends on RCU_BOOST
556 default 1
557 help
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558 This option specifies the real-time priority to which long-term
559 preempted RCU readers are to be boosted. If you are working
560 with a real-time application that has one or more CPU-bound
561 threads running at a real-time priority level, you should set
562 RCU_BOOST_PRIO to a priority higher then the highest-priority
563 real-time CPU-bound thread. The default RCU_BOOST_PRIO value
564 of 1 is appropriate in the common case, which is real-time
565 applications that do not have any CPU-bound threads.
566
567 Some real-time applications might not have a single real-time
568 thread that saturates a given CPU, but instead might have
569 multiple real-time threads that, taken together, fully utilize
570 that CPU. In this case, you should set RCU_BOOST_PRIO to
571 a priority higher than the lowest-priority thread that is
572 conspiring to prevent the CPU from running any non-real-time
573 tasks. For example, if one thread at priority 10 and another
574 thread at priority 5 are between themselves fully consuming
575 the CPU time on a given CPU, then RCU_BOOST_PRIO should be
576 set to priority 6 or higher.
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577
578 Specify the real-time priority, or take the default if unsure.
579
580config RCU_BOOST_DELAY
581 int "Milliseconds to delay boosting after RCU grace-period start"
582 range 0 3000
583 depends on RCU_BOOST
584 default 500
585 help
586 This option specifies the time to wait after the beginning of
587 a given grace period before priority-boosting preempted RCU
588 readers blocking that grace period. Note that any RCU reader
589 blocking an expedited RCU grace period is boosted immediately.
590
591 Accept the default if unsure.
592
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593endmenu # "RCU Subsystem"
594
1da177e4 595config IKCONFIG
f2443ab6 596 tristate "Kernel .config support"
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597 ---help---
598 This option enables the complete Linux kernel ".config" file
599 contents to be saved in the kernel. It provides documentation
600 of which kernel options are used in a running kernel or in an
601 on-disk kernel. This information can be extracted from the kernel
602 image file with the script scripts/extract-ikconfig and used as
603 input to rebuild the current kernel or to build another kernel.
604 It can also be extracted from a running kernel by reading
605 /proc/config.gz if enabled (below).
606
607config IKCONFIG_PROC
608 bool "Enable access to .config through /proc/config.gz"
609 depends on IKCONFIG && PROC_FS
610 ---help---
611 This option enables access to the kernel configuration file
612 through /proc/config.gz.
613
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614config LOG_BUF_SHIFT
615 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
616 range 12 21
f17a32e9 617 default 17
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618 help
619 Select kernel log buffer size as a power of 2.
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620 Examples:
621 17 => 128 KB
622 16 => 64 KB
623 15 => 32 KB
624 14 => 16 KB
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625 13 => 8 KB
626 12 => 4 KB
627
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628#
629# Architectures with an unreliable sched_clock() should select this:
630#
631config HAVE_UNSTABLE_SCHED_CLOCK
632 bool
633
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634menuconfig CGROUPS
635 boolean "Control Group support"
0dea1168 636 depends on EVENTFD
5cdc38f9 637 help
23964d2d 638 This option adds support for grouping sets of processes together, for
5cdc38f9
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639 use with process control subsystems such as Cpusets, CFS, memory
640 controls or device isolation.
641 See
5cdc38f9 642 - Documentation/scheduler/sched-design-CFS.txt (CFS)
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643 - Documentation/cgroups/ (features for grouping, isolation
644 and resource control)
5cdc38f9
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645
646 Say N if unsure.
647
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648if CGROUPS
649
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650config CGROUP_DEBUG
651 bool "Example debug cgroup subsystem"
5cdc38f9
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652 default n
653 help
654 This option enables a simple cgroup subsystem that
655 exports useful debugging information about the cgroups
23964d2d 656 framework.
5cdc38f9 657
23964d2d 658 Say N if unsure.
5cdc38f9 659
5cdc38f9 660config CGROUP_FREEZER
23964d2d 661 bool "Freezer cgroup subsystem"
23964d2d
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662 help
663 Provides a way to freeze and unfreeze all tasks in a
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664 cgroup.
665
666config CGROUP_DEVICE
667 bool "Device controller for cgroups"
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668 help
669 Provides a cgroup implementing whitelists for devices which
670 a process in the cgroup can mknod or open.
671
672config CPUSETS
673 bool "Cpuset support"
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674 help
675 This option will let you create and manage CPUSETs which
676 allow dynamically partitioning a system into sets of CPUs and
677 Memory Nodes and assigning tasks to run only within those sets.
678 This is primarily useful on large SMP or NUMA systems.
679
680 Say N if unsure.
681
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682config PROC_PID_CPUSET
683 bool "Include legacy /proc/<pid>/cpuset file"
684 depends on CPUSETS
685 default y
686
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SV
687config CGROUP_CPUACCT
688 bool "Simple CPU accounting cgroup subsystem"
d842de87
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689 help
690 Provides a simple Resource Controller for monitoring the
23964d2d 691 total CPU consumed by the tasks in a cgroup.
d842de87 692
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693config RESOURCE_COUNTERS
694 bool "Resource counters"
695 help
696 This option enables controller independent resource accounting
23964d2d 697 infrastructure that works with cgroups.
e552b661 698
c255a458 699config MEMCG
00f0b825 700 bool "Memory Resource Controller for Control Groups"
79ae9c29 701 depends on RESOURCE_COUNTERS
cf475ad2 702 select MM_OWNER
00f0b825 703 help
84ad6d70 704 Provides a memory resource controller that manages both anonymous
21acb9ca 705 memory and page cache. (See Documentation/cgroups/memory.txt)
00f0b825
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706
707 Note that setting this option increases fixed memory overhead
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708 associated with each page of memory in the system. By this,
709 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
710 usage tracking struct at boot. Total amount of this is printed out
711 at boot.
00f0b825
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712
713 Only enable when you're ok with these trade offs and really
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714 sure you need the memory resource controller. Even when you enable
715 this, you can set "cgroup_disable=memory" at your boot option to
716 disable memory resource controller and you can avoid overheads.
c9d5409f 717 (and lose benefits of memory resource controller)
00f0b825 718
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719 This config option also selects MM_OWNER config option, which
720 could in turn add some fork/exit overhead.
721
c255a458 722config MEMCG_SWAP
65e0e811 723 bool "Memory Resource Controller Swap Extension"
c255a458 724 depends on MEMCG && SWAP
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725 help
726 Add swap management feature to memory resource controller. When you
727 enable this, you can limit mem+swap usage per cgroup. In other words,
728 when you disable this, memory resource controller has no cares to
729 usage of swap...a process can exhaust all of the swap. This extension
730 is useful when you want to avoid exhaustion swap but this itself
731 adds more overheads and consumes memory for remembering information.
732 Especially if you use 32bit system or small memory system, please
733 be careful about enabling this. When memory resource controller
734 is disabled by boot option, this will be automatically disabled and
735 there will be no overhead from this. Even when you set this config=y,
00a66d29 736 if boot option "swapaccount=0" is set, swap will not be accounted.
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737 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
738 size is 4096bytes, 512k per 1Gbytes of swap.
c255a458 739config MEMCG_SWAP_ENABLED
a42c390c 740 bool "Memory Resource Controller Swap Extension enabled by default"
c255a458 741 depends on MEMCG_SWAP
a42c390c
MH
742 default y
743 help
744 Memory Resource Controller Swap Extension comes with its price in
745 a bigger memory consumption. General purpose distribution kernels
43d547f9 746 which want to enable the feature but keep it disabled by default
a42c390c
MH
747 and let the user enable it by swapaccount boot command line
748 parameter should have this option unselected.
749 For those who want to have the feature enabled by default should
750 select this option (if, for some reason, they need to disable it
00a66d29 751 then swapaccount=0 does the trick).
c255a458 752config MEMCG_KMEM
e5671dfa 753 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
c255a458 754 depends on MEMCG && EXPERIMENTAL
e5671dfa
GC
755 default n
756 help
757 The Kernel Memory extension for Memory Resource Controller can limit
758 the amount of memory used by kernel objects in the system. Those are
759 fundamentally different from the entities handled by the standard
760 Memory Controller, which are page-based, and can be swapped. Users of
761 the kmem extension can use it to guarantee that no group of processes
762 will ever exhaust kernel resources alone.
c077719b 763
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764config CGROUP_HUGETLB
765 bool "HugeTLB Resource Controller for Control Groups"
766 depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL
767 default n
768 help
769 Provides a cgroup Resource Controller for HugeTLB pages.
770 When you enable this, you can put a per cgroup limit on HugeTLB usage.
771 The limit is enforced during page fault. Since HugeTLB doesn't
772 support page reclaim, enforcing the limit at page fault time implies
773 that, the application will get SIGBUS signal if it tries to access
774 HugeTLB pages beyond its limit. This requires the application to know
775 beforehand how much HugeTLB pages it would require for its use. The
776 control group is tracked in the third page lru pointer. This means
777 that we cannot use the controller with huge page less than 3 pages.
778
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SE
779config CGROUP_PERF
780 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
781 depends on PERF_EVENTS && CGROUPS
782 help
783 This option extends the per-cpu mode to restrict monitoring to
2d0f2520 784 threads which belong to the cgroup specified and run on the
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785 designated cpu.
786
787 Say N if unsure.
788
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789menuconfig CGROUP_SCHED
790 bool "Group CPU scheduler"
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DG
791 default n
792 help
793 This feature lets CPU scheduler recognize task groups and control CPU
794 bandwidth allocation to such task groups. It uses cgroups to group
795 tasks.
796
797if CGROUP_SCHED
798config FAIR_GROUP_SCHED
799 bool "Group scheduling for SCHED_OTHER"
800 depends on CGROUP_SCHED
801 default CGROUP_SCHED
802
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PT
803config CFS_BANDWIDTH
804 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
805 depends on EXPERIMENTAL
806 depends on FAIR_GROUP_SCHED
807 default n
808 help
809 This option allows users to define CPU bandwidth rates (limits) for
810 tasks running within the fair group scheduler. Groups with no limit
811 set are considered to be unconstrained and will run with no
812 restriction.
813 See tip/Documentation/scheduler/sched-bwc.txt for more information.
814
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815config RT_GROUP_SCHED
816 bool "Group scheduling for SCHED_RR/FIFO"
817 depends on EXPERIMENTAL
818 depends on CGROUP_SCHED
819 default n
820 help
821 This feature lets you explicitly allocate real CPU bandwidth
32bd7eb5 822 to task groups. If enabled, it will also make it impossible to
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DG
823 schedule realtime tasks for non-root users until you allocate
824 realtime bandwidth for them.
825 See Documentation/scheduler/sched-rt-group.txt for more information.
826
827endif #CGROUP_SCHED
828
afc24d49 829config BLK_CGROUP
32e380ae 830 bool "Block IO controller"
79ae9c29 831 depends on BLOCK
afc24d49
VG
832 default n
833 ---help---
834 Generic block IO controller cgroup interface. This is the common
835 cgroup interface which should be used by various IO controlling
836 policies.
837
838 Currently, CFQ IO scheduler uses it to recognize task groups and
839 control disk bandwidth allocation (proportional time slice allocation)
e43473b7
VG
840 to such task groups. It is also used by bio throttling logic in
841 block layer to implement upper limit in IO rates on a device.
afc24d49
VG
842
843 This option only enables generic Block IO controller infrastructure.
e43473b7 844 One needs to also enable actual IO controlling logic/policy. For
79e2e759
MW
845 enabling proportional weight division of disk bandwidth in CFQ, set
846 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
c5e0591a 847 CONFIG_BLK_DEV_THROTTLING=y.
afc24d49
VG
848
849 See Documentation/cgroups/blkio-controller.txt for more information.
850
851config DEBUG_BLK_CGROUP
852 bool "Enable Block IO controller debugging"
853 depends on BLK_CGROUP
854 default n
855 ---help---
856 Enable some debugging help. Currently it exports additional stat
857 files in a cgroup which can be useful for debugging.
858
23964d2d 859endif # CGROUPS
c077719b 860
067bce1a
CG
861config CHECKPOINT_RESTORE
862 bool "Checkpoint/restore support" if EXPERT
863 default n
864 help
865 Enables additional kernel features in a sake of checkpoint/restore.
866 In particular it adds auxiliary prctl codes to setup process text,
867 data and heap segment sizes, and a few additional /proc filesystem
868 entries.
869
870 If unsure, say N here.
871
8dd2a82c 872menuconfig NAMESPACES
6a108a14
DR
873 bool "Namespaces support" if EXPERT
874 default !EXPERT
c5289a69
PE
875 help
876 Provides the way to make tasks work with different objects using
877 the same id. For example same IPC id may refer to different objects
878 or same user id or pid may refer to different tasks when used in
879 different namespaces.
880
8dd2a82c
DL
881if NAMESPACES
882
58bfdd6d
PE
883config UTS_NS
884 bool "UTS namespace"
17a6d441 885 default y
58bfdd6d
PE
886 help
887 In this namespace tasks see different info provided with the
888 uname() system call
889
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890config IPC_NS
891 bool "IPC namespace"
8dd2a82c 892 depends on (SYSVIPC || POSIX_MQUEUE)
17a6d441 893 default y
ae5e1b22
PE
894 help
895 In this namespace tasks work with IPC ids which correspond to
614b84cf 896 different IPC objects in different namespaces.
ae5e1b22 897
aee16ce7
PE
898config USER_NS
899 bool "User namespace (EXPERIMENTAL)"
8dd2a82c 900 depends on EXPERIMENTAL
e1c972b6 901 depends on UIDGID_CONVERTED
5673a94c 902 select UIDGID_STRICT_TYPE_CHECKS
e1c972b6 903
5673a94c 904 default n
aee16ce7
PE
905 help
906 This allows containers, i.e. vservers, to use user namespaces
907 to provide different user info for different servers.
908 If unsure, say N.
909
74bd59bb 910config PID_NS
9bd38c2c 911 bool "PID Namespaces"
17a6d441 912 default y
74bd59bb 913 help
12d2b8f9 914 Support process id namespaces. This allows having multiple
692105b8 915 processes with the same pid as long as they are in different
74bd59bb
PE
916 pid namespaces. This is a building block of containers.
917
d6eb633f
MH
918config NET_NS
919 bool "Network namespace"
8dd2a82c 920 depends on NET
17a6d441 921 default y
d6eb633f
MH
922 help
923 Allow user space to create what appear to be multiple instances
924 of the network stack.
925
8dd2a82c
DL
926endif # NAMESPACES
927
e1c972b6
EB
928config UIDGID_CONVERTED
929 # True if all of the selected software conmponents are known
930 # to have uid_t and gid_t converted to kuid_t and kgid_t
931 # where appropriate and are otherwise safe to use with
932 # the user namespace.
933 bool
934 default y
935
936 # List of kernel pieces that need user namespace work
937 # Features
e1c972b6
EB
938 depends on SYSVIPC = n
939 depends on IMA = n
940 depends on EVM = n
941 depends on KEYS = n
942 depends on AUDIT = n
943 depends on AUDITSYSCALL = n
944 depends on TASKSTATS = n
945 depends on TRACING = n
946 depends on FS_POSIX_ACL = n
947 depends on QUOTA = n
948 depends on QUOTACTL = n
949 depends on DEBUG_CREDENTIALS = n
950 depends on BSD_PROCESS_ACCT = n
951 depends on DRM = n
952 depends on PROC_EVENTS = n
953
954 # Networking
955 depends on NET = n
956 depends on NET_9P = n
957 depends on IPX = n
958 depends on PHONET = n
959 depends on NET_CLS_FLOW = n
960 depends on NETFILTER_XT_MATCH_OWNER = n
961 depends on NETFILTER_XT_MATCH_RECENT = n
962 depends on NETFILTER_XT_TARGET_LOG = n
963 depends on NETFILTER_NETLINK_LOG = n
964 depends on INET = n
965 depends on IPV6 = n
966 depends on IP_SCTP = n
967 depends on AF_RXRPC = n
968 depends on LLC2 = n
969 depends on NET_KEY = n
970 depends on INET_DIAG = n
971 depends on DNS_RESOLVER = n
972 depends on AX25 = n
973 depends on ATALK = n
974
975 # Filesystems
976 depends on USB_DEVICEFS = n
977 depends on USB_GADGETFS = n
978 depends on USB_FUNCTIONFS = n
979 depends on DEVTMPFS = n
980 depends on XENFS = n
981
982 depends on 9P_FS = n
983 depends on ADFS_FS = n
984 depends on AFFS_FS = n
985 depends on AFS_FS = n
986 depends on AUTOFS4_FS = n
987 depends on BEFS_FS = n
988 depends on BFS_FS = n
989 depends on BTRFS_FS = n
990 depends on CEPH_FS = n
991 depends on CIFS = n
992 depends on CODA_FS = n
993 depends on CONFIGFS_FS = n
994 depends on CRAMFS = n
995 depends on DEBUG_FS = n
996 depends on ECRYPT_FS = n
997 depends on EFS_FS = n
998 depends on EXOFS_FS = n
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EB
999 depends on FAT_FS = n
1000 depends on FUSE_FS = n
1001 depends on GFS2_FS = n
1002 depends on HFS_FS = n
1003 depends on HFSPLUS_FS = n
1004 depends on HPFS_FS = n
1005 depends on HUGETLBFS = n
1006 depends on ISO9660_FS = n
1007 depends on JFFS2_FS = n
1008 depends on JFS_FS = n
1009 depends on LOGFS = n
1010 depends on MINIX_FS = n
1011 depends on NCP_FS = n
1012 depends on NFSD = n
1013 depends on NFS_FS = n
1014 depends on NILFS2_FS = n
1015 depends on NTFS_FS = n
1016 depends on OCFS2_FS = n
1017 depends on OMFS_FS = n
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EB
1018 depends on QNX4FS_FS = n
1019 depends on QNX6FS_FS = n
1020 depends on REISERFS_FS = n
1021 depends on SQUASHFS = n
e1c972b6 1022 depends on SYSV_FS = n
e1c972b6
EB
1023 depends on UBIFS_FS = n
1024 depends on UDF_FS = n
1025 depends on UFS_FS = n
1026 depends on VXFS_FS = n
1027 depends on XFS_FS = n
1028
1029 depends on !UML || HOSTFS = n
1030
1031 # The rare drivers that won't build
1032 depends on AIRO = n
1033 depends on AIRO_CS = n
1034 depends on TUN = n
1035 depends on INFINIBAND_QIB = n
1036 depends on BLK_DEV_LOOP = n
1037 depends on ANDROID_BINDER_IPC = n
1038
1039 # Security modules
1040 depends on SECURITY_TOMOYO = n
1041 depends on SECURITY_APPARMOR = n
1042
5673a94c
EB
1043config UIDGID_STRICT_TYPE_CHECKS
1044 bool "Require conversions between uid/gids and their internal representation"
e1c972b6 1045 depends on UIDGID_CONVERTED
5673a94c
EB
1046 default n
1047 help
1048 While the nececessary conversions are being added to all subsystems this option allows
1049 the code to continue to build for unconverted subsystems.
1050
1051 Say Y here if you want the strict type checking enabled
1052
5091faa4
MG
1053config SCHED_AUTOGROUP
1054 bool "Automatic process group scheduling"
1055 select EVENTFD
1056 select CGROUPS
1057 select CGROUP_SCHED
1058 select FAIR_GROUP_SCHED
1059 help
1060 This option optimizes the scheduler for common desktop workloads by
1061 automatically creating and populating task groups. This separation
1062 of workloads isolates aggressive CPU burners (like build jobs) from
1063 desktop applications. Task group autogeneration is currently based
1064 upon task session.
1065
7af37bec
DL
1066config MM_OWNER
1067 bool
1068
1069config SYSFS_DEPRECATED
5d6a4ea5 1070 bool "Enable deprecated sysfs features to support old userspace tools"
7af37bec
DL
1071 depends on SYSFS
1072 default n
1073 help
1074 This option adds code that switches the layout of the "block" class
1075 devices, to not show up in /sys/class/block/, but only in
1076 /sys/block/.
1077
1078 This switch is only active when the sysfs.deprecated=1 boot option is
1079 passed or the SYSFS_DEPRECATED_V2 option is set.
1080
1081 This option allows new kernels to run on old distributions and tools,
1082 which might get confused by /sys/class/block/. Since 2007/2008 all
1083 major distributions and tools handle this just fine.
1084
1085 Recent distributions and userspace tools after 2009/2010 depend on
1086 the existence of /sys/class/block/, and will not work with this
1087 option enabled.
1088
1089 Only if you are using a new kernel on an old distribution, you might
1090 need to say Y here.
1091
1092config SYSFS_DEPRECATED_V2
5d6a4ea5 1093 bool "Enable deprecated sysfs features by default"
7af37bec
DL
1094 default n
1095 depends on SYSFS
1096 depends on SYSFS_DEPRECATED
1097 help
1098 Enable deprecated sysfs by default.
1099
1100 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1101 option.
1102
1103 Only if you are using a new kernel on an old distribution, you might
1104 need to say Y here. Even then, odds are you would not need it
1105 enabled, you can always pass the boot option if absolutely necessary.
1106
1107config RELAY
1108 bool "Kernel->user space relay support (formerly relayfs)"
1109 help
1110 This option enables support for relay interface support in
1111 certain file systems (such as debugfs).
1112 It is designed to provide an efficient mechanism for tools and
1113 facilities to relay large amounts of data from kernel space to
1114 user space.
1115
1116 If unsure, say N.
1117
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DG
1118config BLK_DEV_INITRD
1119 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1120 depends on BROKEN || !FRV
1121 help
1122 The initial RAM filesystem is a ramfs which is loaded by the
1123 boot loader (loadlin or lilo) and that is mounted as root
1124 before the normal boot procedure. It is typically used to
1125 load modules needed to mount the "real" root file system,
1126 etc. See <file:Documentation/initrd.txt> for details.
1127
1128 If RAM disk support (BLK_DEV_RAM) is also included, this
1129 also enables initial RAM disk (initrd) support and adds
1130 15 Kbytes (more on some other architectures) to the kernel size.
1131
1132 If unsure say Y.
1133
c33df4ea
JPS
1134if BLK_DEV_INITRD
1135
dbec4866
SR
1136source "usr/Kconfig"
1137
c33df4ea
JPS
1138endif
1139
c45b4f1f 1140config CC_OPTIMIZE_FOR_SIZE
96fffeb4 1141 bool "Optimize for size"
c45b4f1f
LT
1142 help
1143 Enabling this option will pass "-Os" instead of "-O2" to gcc
1144 resulting in a smaller kernel.
1145
775a7229 1146 If unsure, say Y.
c45b4f1f 1147
0847062a
RD
1148config SYSCTL
1149 bool
1150
b943c460
RD
1151config ANON_INODES
1152 bool
1153
6a108a14
DR
1154menuconfig EXPERT
1155 bool "Configure standard kernel features (expert users)"
f505c553
JT
1156 # Unhide debug options, to make the on-by-default options visible
1157 select DEBUG_KERNEL
1da177e4
LT
1158 help
1159 This option allows certain base kernel options and settings
1160 to be disabled or tweaked. This is for specialized
1161 environments which can tolerate a "non-standard" kernel.
1162 Only use this if you really know what you are doing.
1163
ae81f9e3 1164config UID16
6a108a14 1165 bool "Enable 16-bit UID system calls" if EXPERT
09337f50 1166 depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
ae81f9e3
CE
1167 default y
1168 help
1169 This enables the legacy 16-bit UID syscall wrappers.
1170
b89a8171 1171config SYSCTL_SYSCALL
6a108a14 1172 bool "Sysctl syscall support" if EXPERT
26a7034b 1173 depends on PROC_SYSCTL
c736de60 1174 default n
b89a8171 1175 select SYSCTL
ae81f9e3 1176 ---help---
13bb7e37
EB
1177 sys_sysctl uses binary paths that have been found challenging
1178 to properly maintain and use. The interface in /proc/sys
1179 using paths with ascii names is now the primary path to this
1180 information.
b89a8171 1181
13bb7e37
EB
1182 Almost nothing using the binary sysctl interface so if you are
1183 trying to save some space it is probably safe to disable this,
1184 making your kernel marginally smaller.
b89a8171 1185
c736de60 1186 If unsure say N here.
ae81f9e3 1187
1da177e4 1188config KALLSYMS
6a108a14 1189 bool "Load all symbols for debugging/ksymoops" if EXPERT
1da177e4
LT
1190 default y
1191 help
1192 Say Y here to let the kernel print out symbolic crash information and
1193 symbolic stack backtraces. This increases the size of the kernel
1194 somewhat, as all symbols have to be loaded into the kernel image.
1195
1196config KALLSYMS_ALL
1197 bool "Include all symbols in kallsyms"
1198 depends on DEBUG_KERNEL && KALLSYMS
1199 help
71a83ec7
AB
1200 Normally kallsyms only contains the symbols of functions for nicer
1201 OOPS messages and backtraces (i.e., symbols from the text and inittext
1202 sections). This is sufficient for most cases. And only in very rare
1203 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1204 names of variables from the data sections, etc).
1205
1206 This option makes sure that all symbols are loaded into the kernel
1207 image (i.e., symbols from all sections) in cost of increased kernel
1208 size (depending on the kernel configuration, it may be 300KiB or
1209 something like this).
1210
1211 Say N unless you really need all symbols.
d59745ce 1212
712f47ce 1213config HOTPLUG
6a108a14 1214 bool "Support for hot-pluggable devices" if EXPERT
712f47ce
GKH
1215 default y
1216 help
1217 This option is provided for the case where no hotplug or uevent
1218 capabilities is wanted by the kernel. You should only consider
1219 disabling this option for embedded systems that do not use modules, a
1220 dynamic /dev tree, or dynamic device discovery. Just say Y.
1221
d59745ce
MM
1222config PRINTK
1223 default y
6a108a14 1224 bool "Enable support for printk" if EXPERT
d59745ce
MM
1225 help
1226 This option enables normal printk support. Removing it
1227 eliminates most of the message strings from the kernel image
1228 and makes the kernel more or less silent. As this makes it
1229 very difficult to diagnose system problems, saying N here is
1230 strongly discouraged.
1231
c8538a7a 1232config BUG
6a108a14 1233 bool "BUG() support" if EXPERT
c8538a7a
MM
1234 default y
1235 help
1236 Disabling this option eliminates support for BUG and WARN, reducing
1237 the size of your kernel image and potentially quietly ignoring
1238 numerous fatal conditions. You should only consider disabling this
1239 option for embedded systems with no facilities for reporting errors.
1240 Just say Y.
1241
708e9a79
MM
1242config ELF_CORE
1243 default y
6a108a14 1244 bool "Enable ELF core dumps" if EXPERT
708e9a79
MM
1245 help
1246 Enable support for generating core dumps. Disabling saves about 4k.
1247
8761f1ab 1248
e5e1d3cb 1249config PCSPKR_PLATFORM
6a108a14 1250 bool "Enable PC-Speaker support" if EXPERT
8761f1ab 1251 depends on HAVE_PCSPKR_PLATFORM
15f304b6 1252 select I8253_LOCK
e5e1d3cb
SS
1253 default y
1254 help
1255 This option allows to disable the internal PC-Speaker
1256 support, saving some memory.
1257
8761f1ab
RB
1258config HAVE_PCSPKR_PLATFORM
1259 bool
1260
1da177e4
LT
1261config BASE_FULL
1262 default y
6a108a14 1263 bool "Enable full-sized data structures for core" if EXPERT
1da177e4
LT
1264 help
1265 Disabling this option reduces the size of miscellaneous core
1266 kernel data structures. This saves memory on small machines,
1267 but may reduce performance.
1268
1269config FUTEX
6a108a14 1270 bool "Enable futex support" if EXPERT
1da177e4 1271 default y
23f78d4a 1272 select RT_MUTEXES
1da177e4
LT
1273 help
1274 Disabling this option will cause the kernel to be built without
1275 support for "fast userspace mutexes". The resulting kernel may not
1276 run glibc-based applications correctly.
1277
1278config EPOLL
6a108a14 1279 bool "Enable eventpoll support" if EXPERT
1da177e4 1280 default y
448e3cee 1281 select ANON_INODES
1da177e4
LT
1282 help
1283 Disabling this option will cause the kernel to be built without
1284 support for epoll family of system calls.
1285
fba2afaa 1286config SIGNALFD
6a108a14 1287 bool "Enable signalfd() system call" if EXPERT
448e3cee 1288 select ANON_INODES
fba2afaa
DL
1289 default y
1290 help
1291 Enable the signalfd() system call that allows to receive signals
1292 on a file descriptor.
1293
1294 If unsure, say Y.
1295
b215e283 1296config TIMERFD
6a108a14 1297 bool "Enable timerfd() system call" if EXPERT
448e3cee 1298 select ANON_INODES
b215e283
DL
1299 default y
1300 help
1301 Enable the timerfd() system call that allows to receive timer
1302 events on a file descriptor.
1303
1304 If unsure, say Y.
1305
e1ad7468 1306config EVENTFD
6a108a14 1307 bool "Enable eventfd() system call" if EXPERT
448e3cee 1308 select ANON_INODES
e1ad7468
DL
1309 default y
1310 help
1311 Enable the eventfd() system call that allows to receive both
1312 kernel notification (ie. KAIO) or userspace notifications.
1313
1314 If unsure, say Y.
1315
1da177e4 1316config SHMEM
6a108a14 1317 bool "Use full shmem filesystem" if EXPERT
1da177e4
LT
1318 default y
1319 depends on MMU
1320 help
1321 The shmem is an internal filesystem used to manage shared memory.
1322 It is backed by swap and manages resource limits. It is also exported
1323 to userspace as tmpfs if TMPFS is enabled. Disabling this
1324 option replaces shmem and tmpfs with the much simpler ramfs code,
1325 which may be appropriate on small systems without swap.
1326
ebf3f09c 1327config AIO
6a108a14 1328 bool "Enable AIO support" if EXPERT
ebf3f09c
TP
1329 default y
1330 help
1331 This option enables POSIX asynchronous I/O which may by used
1332 by some high performance threaded applications. Disabling
1333 this option saves about 7k.
1334
6befe5f6
RD
1335config EMBEDDED
1336 bool "Embedded system"
1337 select EXPERT
1338 help
1339 This option should be enabled if compiling the kernel for
1340 an embedded system so certain expert options are available
1341 for configuration.
1342
cdd6c482 1343config HAVE_PERF_EVENTS
0793a61d 1344 bool
018df72d
MF
1345 help
1346 See tools/perf/design.txt for details.
0793a61d 1347
906010b2
PZ
1348config PERF_USE_VMALLOC
1349 bool
1350 help
1351 See tools/perf/design.txt for details
1352
57c0c15b 1353menu "Kernel Performance Events And Counters"
0793a61d 1354
cdd6c482 1355config PERF_EVENTS
57c0c15b 1356 bool "Kernel performance events and counters"
392d65a9 1357 default y if PROFILING
cdd6c482 1358 depends on HAVE_PERF_EVENTS
4c59e467 1359 select ANON_INODES
e360adbe 1360 select IRQ_WORK
0793a61d 1361 help
57c0c15b
IM
1362 Enable kernel support for various performance events provided
1363 by software and hardware.
0793a61d 1364
dd77038d 1365 Software events are supported either built-in or via the
57c0c15b 1366 use of generic tracepoints.
0793a61d 1367
57c0c15b
IM
1368 Most modern CPUs support performance events via performance
1369 counter registers. These registers count the number of certain
0793a61d
TG
1370 types of hw events: such as instructions executed, cachemisses
1371 suffered, or branches mis-predicted - without slowing down the
1372 kernel or applications. These registers can also trigger interrupts
1373 when a threshold number of events have passed - and can thus be
1374 used to profile the code that runs on that CPU.
1375
57c0c15b 1376 The Linux Performance Event subsystem provides an abstraction of
dd77038d 1377 these software and hardware event capabilities, available via a
57c0c15b 1378 system call and used by the "perf" utility in tools/perf/. It
0793a61d
TG
1379 provides per task and per CPU counters, and it provides event
1380 capabilities on top of those.
1381
1382 Say Y if unsure.
1383
906010b2
PZ
1384config DEBUG_PERF_USE_VMALLOC
1385 default n
1386 bool "Debug: use vmalloc to back perf mmap() buffers"
1387 depends on PERF_EVENTS && DEBUG_KERNEL
1388 select PERF_USE_VMALLOC
1389 help
1390 Use vmalloc memory to back perf mmap() buffers.
1391
1392 Mostly useful for debugging the vmalloc code on platforms
1393 that don't require it.
1394
1395 Say N if unsure.
1396
0793a61d
TG
1397endmenu
1398
f8891e5e
CL
1399config VM_EVENT_COUNTERS
1400 default y
6a108a14 1401 bool "Enable VM event counters for /proc/vmstat" if EXPERT
f8891e5e 1402 help
2aea4fb6
PJ
1403 VM event counters are needed for event counts to be shown.
1404 This option allows the disabling of the VM event counters
6a108a14 1405 on EXPERT systems. /proc/vmstat will only show page counts
2aea4fb6 1406 if VM event counters are disabled.
f8891e5e 1407
3d137310
TP
1408config PCI_QUIRKS
1409 default y
6a108a14 1410 bool "Enable PCI quirk workarounds" if EXPERT
61cfc7e4 1411 depends on PCI
3d137310
TP
1412 help
1413 This enables workarounds for various PCI chipset
1414 bugs/quirks. Disable this only if your target machine is
1415 unaffected by PCI quirks.
1416
41ecc55b
CL
1417config SLUB_DEBUG
1418 default y
6a108a14 1419 bool "Enable SLUB debugging support" if EXPERT
f6acb635 1420 depends on SLUB && SYSFS
41ecc55b
CL
1421 help
1422 SLUB has extensive debug support features. Disabling these can
1423 result in significant savings in code size. This also disables
1424 SLUB sysfs support. /sys/slab will not exist and there will be
1425 no support for cache validation etc.
1426
b943c460
RD
1427config COMPAT_BRK
1428 bool "Disable heap randomization"
1429 default y
1430 help
1431 Randomizing heap placement makes heap exploits harder, but it
1432 also breaks ancient binaries (including anything libc5 based).
1433 This option changes the bootup default to heap randomization
692105b8 1434 disabled, and can be overridden at runtime by setting
b943c460
RD
1435 /proc/sys/kernel/randomize_va_space to 2.
1436
1437 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1438
81819f0f
CL
1439choice
1440 prompt "Choose SLAB allocator"
a0acd820 1441 default SLUB
81819f0f
CL
1442 help
1443 This option allows to select a slab allocator.
1444
1445config SLAB
1446 bool "SLAB"
1447 help
1448 The regular slab allocator that is established and known to work
34013886 1449 well in all environments. It organizes cache hot objects in
02f56210 1450 per cpu and per node queues.
81819f0f
CL
1451
1452config SLUB
81819f0f
CL
1453 bool "SLUB (Unqueued Allocator)"
1454 help
1455 SLUB is a slab allocator that minimizes cache line usage
1456 instead of managing queues of cached objects (SLAB approach).
1457 Per cpu caching is realized using slabs of objects instead
1458 of queues of objects. SLUB can use memory efficiently
02f56210
SA
1459 and has enhanced diagnostics. SLUB is the default choice for
1460 a slab allocator.
81819f0f
CL
1461
1462config SLOB
6a108a14 1463 depends on EXPERT
81819f0f
CL
1464 bool "SLOB (Simple Allocator)"
1465 help
37291458
MM
1466 SLOB replaces the stock allocator with a drastically simpler
1467 allocator. SLOB is generally more space efficient but
1468 does not perform as well on large systems.
81819f0f
CL
1469
1470endchoice
1471
ea637639
JZ
1472config MMAP_ALLOW_UNINITIALIZED
1473 bool "Allow mmapped anonymous memory to be uninitialized"
6a108a14 1474 depends on EXPERT && !MMU
ea637639
JZ
1475 default n
1476 help
1477 Normally, and according to the Linux spec, anonymous memory obtained
1478 from mmap() has it's contents cleared before it is passed to
1479 userspace. Enabling this config option allows you to request that
1480 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1481 providing a huge performance boost. If this option is not enabled,
1482 then the flag will be ignored.
1483
1484 This is taken advantage of by uClibc's malloc(), and also by
1485 ELF-FDPIC binfmt's brk and stack allocator.
1486
1487 Because of the obvious security issues, this option should only be
1488 enabled on embedded devices where you control what is run in
1489 userspace. Since that isn't generally a problem on no-MMU systems,
1490 it is normally safe to say Y here.
1491
1492 See Documentation/nommu-mmap.txt for more information.
1493
125e5645 1494config PROFILING
b309a294 1495 bool "Profiling support"
125e5645
MD
1496 help
1497 Say Y here to enable the extended profiling support mechanisms used
1498 by profilers such as OProfile.
1499
5f87f112
IM
1500#
1501# Place an empty function call at each tracepoint site. Can be
1502# dynamically changed for a probe function.
1503#
97e1c18e 1504config TRACEPOINTS
5f87f112 1505 bool
97e1c18e 1506
fb32e03f
MD
1507source "arch/Kconfig"
1508
1da177e4
LT
1509endmenu # General setup
1510
ee7e5516
DES
1511config HAVE_GENERIC_DMA_COHERENT
1512 bool
1513 default n
1514
158a9624
LT
1515config SLABINFO
1516 bool
1517 depends on PROC_FS
0f389ec6 1518 depends on SLAB || SLUB_DEBUG
158a9624
LT
1519 default y
1520
ae81f9e3
CE
1521config RT_MUTEXES
1522 boolean
ae81f9e3 1523
1da177e4
LT
1524config BASE_SMALL
1525 int
1526 default 0 if BASE_FULL
1527 default 1 if !BASE_FULL
1528
66da5733 1529menuconfig MODULES
1da177e4
LT
1530 bool "Enable loadable module support"
1531 help
1532 Kernel modules are small pieces of compiled code which can
1533 be inserted in the running kernel, rather than being
1534 permanently built into the kernel. You use the "modprobe"
1535 tool to add (and sometimes remove) them. If you say Y here,
1536 many parts of the kernel can be built as modules (by
1537 answering M instead of Y where indicated): this is most
1538 useful for infrequently used options which are not required
1539 for booting. For more information, see the man pages for
1540 modprobe, lsmod, modinfo, insmod and rmmod.
1541
1542 If you say Y here, you will need to run "make
1543 modules_install" to put the modules under /lib/modules/
1544 where modprobe can find them (you may need to be root to do
1545 this).
1546
1547 If unsure, say Y.
1548
0b0de144
RD
1549if MODULES
1550
826e4506
LT
1551config MODULE_FORCE_LOAD
1552 bool "Forced module loading"
826e4506
LT
1553 default n
1554 help
91e37a79
RR
1555 Allow loading of modules without version information (ie. modprobe
1556 --force). Forced module loading sets the 'F' (forced) taint flag and
1557 is usually a really bad idea.
826e4506 1558
1da177e4
LT
1559config MODULE_UNLOAD
1560 bool "Module unloading"
1da177e4
LT
1561 help
1562 Without this option you will not be able to unload any
1563 modules (note that some modules may not be unloadable
f7f5b675
DV
1564 anyway), which makes your kernel smaller, faster
1565 and simpler. If unsure, say Y.
1da177e4
LT
1566
1567config MODULE_FORCE_UNLOAD
1568 bool "Forced module unloading"
1569 depends on MODULE_UNLOAD && EXPERIMENTAL
1570 help
1571 This option allows you to force a module to unload, even if the
1572 kernel believes it is unsafe: the kernel will remove the module
1573 without waiting for anyone to stop using it (using the -f option to
1574 rmmod). This is mainly for kernel developers and desperate users.
1575 If unsure, say N.
1576
1da177e4 1577config MODVERSIONS
0d541643 1578 bool "Module versioning support"
1da177e4
LT
1579 help
1580 Usually, you have to use modules compiled with your kernel.
1581 Saying Y here makes it sometimes possible to use modules
1582 compiled for different kernels, by adding enough information
1583 to the modules to (hopefully) spot any changes which would
1584 make them incompatible with the kernel you are running. If
1585 unsure, say N.
1586
1587config MODULE_SRCVERSION_ALL
1588 bool "Source checksum for all modules"
1da177e4
LT
1589 help
1590 Modules which contain a MODULE_VERSION get an extra "srcversion"
1591 field inserted into their modinfo section, which contains a
1592 sum of the source files which made it. This helps maintainers
1593 see exactly which source was used to build a module (since
1594 others sometimes change the module source without updating
1595 the version). With this option, such a "srcversion" field
1596 will be created for all modules. If unsure, say N.
1597
0b0de144
RD
1598endif # MODULES
1599
98a79d6a
RR
1600config INIT_ALL_POSSIBLE
1601 bool
1602 help
5f054e31
RR
1603 Back when each arch used to define their own cpu_online_mask and
1604 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
98a79d6a
RR
1605 with all 1s, and others with all 0s. When they were centralised,
1606 it was better to provide this option than to break all the archs
692105b8 1607 and have several arch maintainers pursuing me down dark alleys.
98a79d6a 1608
1da177e4
LT
1609config STOP_MACHINE
1610 bool
1611 default y
1612 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
1613 help
1614 Need stop_machine() primitive.
3a65dfe8 1615
3a65dfe8 1616source "block/Kconfig"
e98c3202
AK
1617
1618config PREEMPT_NOTIFIERS
1619 bool
e260be67 1620
16295bec
SK
1621config PADATA
1622 depends on SMP
1623 bool
1624
6beb0009 1625source "kernel/Kconfig.locks"