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80daa560 RZ |
1 | config ARCH |
2 | string | |
3 | option env="ARCH" | |
4 | ||
5 | config KERNELVERSION | |
6 | string | |
7 | option env="KERNELVERSION" | |
8 | ||
face4374 RZ |
9 | config DEFCONFIG_LIST |
10 | string | |
b2670eac | 11 | depends on !UML |
face4374 RZ |
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 "$ARCH_DEFCONFIG" |
face4374 RZ |
17 | default "arch/$ARCH/defconfig" |
18 | ||
b99b87f7 PO |
19 | config CONSTRUCTORS |
20 | bool | |
21 | depends on !UML | |
b99b87f7 | 22 | |
e360adbe PZ |
23 | config HAVE_IRQ_WORK |
24 | bool | |
25 | ||
26 | config IRQ_WORK | |
27 | bool | |
28 | depends on HAVE_IRQ_WORK | |
29 | ||
1dbdc6f1 DD |
30 | config BUILDTIME_EXTABLE_SORT |
31 | bool | |
32 | ||
ff0cfc66 | 33 | menu "General setup" |
1da177e4 LT |
34 | |
35 | config 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56 | drivers that have been replaced by something else, and/or are | |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 | ||
1da177e4 LT |
66 | config BROKEN |
67 | bool | |
1da177e4 LT |
68 | |
69 | config BROKEN_ON_SMP | |
70 | bool | |
71 | depends on BROKEN || !SMP | |
72 | default y | |
73 | ||
1da177e4 LT |
74 | config INIT_ENV_ARG_LIMIT |
75 | int | |
dd673bca AB |
76 | default 32 if !UML |
77 | default 128 if UML | |
1da177e4 | 78 | help |
34ad92c2 RD |
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 | |
84336466 RM |
83 | config 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 | ||
1da177e4 LT |
91 | config 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 | ||
aaebf433 RA |
101 | config 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 | |
6e5a5420 RD |
106 | release tree by looking for git tags that belong to the current |
107 | top of tree revision. | |
aaebf433 RA |
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 | |
6e5a5420 RD |
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 | |
2e9f3bdd PA |
121 | config HAVE_KERNEL_GZIP |
122 | bool | |
123 | ||
124 | config HAVE_KERNEL_BZIP2 | |
125 | bool | |
126 | ||
127 | config HAVE_KERNEL_LZMA | |
128 | bool | |
129 | ||
3ebe1243 LC |
130 | config HAVE_KERNEL_XZ |
131 | bool | |
132 | ||
7dd65feb AT |
133 | config HAVE_KERNEL_LZO |
134 | bool | |
135 | ||
30d65dbf | 136 | choice |
2e9f3bdd PA |
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 |
30d65dbf AK |
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) <[email protected]>. (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 | ||
158 | config KERNEL_GZIP | |
2e9f3bdd PA |
159 | bool "Gzip" |
160 | depends on HAVE_KERNEL_GZIP | |
161 | help | |
7dd65feb AT |
162 | The old and tried gzip compression. It provides a good balance |
163 | between compression ratio and decompression speed. | |
30d65dbf AK |
164 | |
165 | config KERNEL_BZIP2 | |
166 | bool "Bzip2" | |
2e9f3bdd | 167 | depends on HAVE_KERNEL_BZIP2 |
30d65dbf AK |
168 | help |
169 | Its compression ratio and speed is intermediate. | |
0a4dd35c | 170 | Decompression speed is slowest among the choices. The kernel |
2e9f3bdd PA |
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. | |
30d65dbf AK |
174 | |
175 | config KERNEL_LZMA | |
2e9f3bdd PA |
176 | bool "LZMA" |
177 | depends on HAVE_KERNEL_LZMA | |
178 | help | |
0a4dd35c RD |
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 | |
3ebe1243 LC |
183 | config 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 | ||
7dd65feb AT |
198 | config 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 |
7dd65feb AT |
204 | (both compression and decompression) is the fastest. |
205 | ||
30d65dbf AK |
206 | endchoice |
207 | ||
bd5dc17b JT |
208 | config 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 | ||
1da177e4 LT |
217 | config SWAP |
218 | bool "Support for paging of anonymous memory (swap)" | |
9361401e | 219 | depends on MMU && BLOCK |
1da177e4 LT |
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 |
1da177e4 LT |
224 | used to provide more virtual memory than the actual RAM present |
225 | in your computer. If unsure say Y. | |
226 | ||
227 | config SYSVIPC | |
228 | bool "System V IPC" | |
1da177e4 LT |
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 | ||
a5494dcd EB |
242 | config SYSVIPC_SYSCTL |
243 | bool | |
244 | depends on SYSVIPC | |
245 | depends on SYSCTL | |
246 | default y | |
247 | ||
1da177e4 LT |
248 | config 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. |
1da177e4 LT |
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 | ||
bdc8e5f8 SH |
264 | config POSIX_MQUEUE_SYSCTL |
265 | bool | |
266 | depends on POSIX_MQUEUE | |
267 | depends on SYSCTL | |
268 | default y | |
269 | ||
391dc69c FW |
270 | config FHANDLE |
271 | bool "open by fhandle syscalls" | |
272 | select EXPORTFS | |
273 | help | |
274 | If you say Y here, a user level program will be able to map | |
275 | file names to handle and then later use the handle for | |
276 | different file system operations. This is useful in implementing | |
277 | userspace file servers, which now track files using handles instead | |
278 | of names. The handle would remain the same even if file names | |
279 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) | |
280 | syscalls. | |
281 | ||
282 | config AUDIT | |
283 | bool "Auditing support" | |
284 | depends on NET | |
285 | help | |
286 | Enable auditing infrastructure that can be used with another | |
287 | kernel subsystem, such as SELinux (which requires this for | |
288 | logging of avc messages output). Does not do system-call | |
289 | auditing without CONFIG_AUDITSYSCALL. | |
290 | ||
291 | config AUDITSYSCALL | |
292 | bool "Enable system-call auditing support" | |
293 | depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT)) | |
294 | default y if SECURITY_SELINUX | |
295 | help | |
296 | Enable low-overhead system-call auditing infrastructure that | |
297 | can be used independently or with another kernel subsystem, | |
298 | such as SELinux. | |
299 | ||
300 | config AUDIT_WATCH | |
301 | def_bool y | |
302 | depends on AUDITSYSCALL | |
303 | select FSNOTIFY | |
304 | ||
305 | config AUDIT_TREE | |
306 | def_bool y | |
307 | depends on AUDITSYSCALL | |
308 | select FSNOTIFY | |
309 | ||
310 | config AUDIT_LOGINUID_IMMUTABLE | |
311 | bool "Make audit loginuid immutable" | |
312 | depends on AUDIT | |
313 | help | |
314 | The config option toggles if a task setting its loginuid requires | |
315 | CAP_SYS_AUDITCONTROL or if that task should require no special permissions | |
316 | but should instead only allow setting its loginuid if it was never | |
317 | previously set. On systems which use systemd or a similar central | |
318 | process to restart login services this should be set to true. On older | |
319 | systems in which an admin would typically have to directly stop and | |
320 | start processes this should be set to false. Setting this to true allows | |
321 | one to drop potentially dangerous capabilites from the login tasks, | |
322 | but may not be backwards compatible with older init systems. | |
323 | ||
324 | source "kernel/irq/Kconfig" | |
325 | source "kernel/time/Kconfig" | |
326 | ||
327 | menu "CPU/Task time and stats accounting" | |
328 | ||
fdf9c356 FW |
329 | choice |
330 | prompt "Cputime accounting" | |
331 | default TICK_CPU_ACCOUNTING if !PPC64 | |
332 | default VIRT_CPU_ACCOUNTING if PPC64 | |
333 | ||
334 | # Kind of a stub config for the pure tick based cputime accounting | |
335 | config TICK_CPU_ACCOUNTING | |
336 | bool "Simple tick based cputime accounting" | |
337 | depends on !S390 | |
338 | help | |
339 | This is the basic tick based cputime accounting that maintains | |
340 | statistics about user, system and idle time spent on per jiffies | |
341 | granularity. | |
342 | ||
343 | If unsure, say Y. | |
344 | ||
b952741c FW |
345 | config VIRT_CPU_ACCOUNTING |
346 | bool "Deterministic task and CPU time accounting" | |
347 | depends on HAVE_VIRT_CPU_ACCOUNTING | |
b952741c FW |
348 | help |
349 | Select this option to enable more accurate task and CPU time | |
350 | accounting. This is done by reading a CPU counter on each | |
351 | kernel entry and exit and on transitions within the kernel | |
352 | between system, softirq and hardirq state, so there is a | |
353 | small performance impact. In the case of s390 or IBM POWER > 5, | |
354 | this also enables accounting of stolen time on logically-partitioned | |
355 | systems. | |
356 | ||
fdf9c356 FW |
357 | config IRQ_TIME_ACCOUNTING |
358 | bool "Fine granularity task level IRQ time accounting" | |
359 | depends on HAVE_IRQ_TIME_ACCOUNTING | |
360 | help | |
361 | Select this option to enable fine granularity task irq time | |
362 | accounting. This is done by reading a timestamp on each | |
363 | transitions between softirq and hardirq state, so there can be a | |
364 | small performance impact. | |
365 | ||
366 | If in doubt, say N here. | |
367 | ||
368 | endchoice | |
369 | ||
1da177e4 LT |
370 | config BSD_PROCESS_ACCT |
371 | bool "BSD Process Accounting" | |
372 | help | |
373 | If you say Y here, a user level program will be able to instruct the | |
374 | kernel (via a special system call) to write process accounting | |
375 | information to a file: whenever a process exits, information about | |
376 | that process will be appended to the file by the kernel. The | |
377 | information includes things such as creation time, owning user, | |
378 | command name, memory usage, controlling terminal etc. (the complete | |
379 | list is in the struct acct in <file:include/linux/acct.h>). It is | |
380 | up to the user level program to do useful things with this | |
381 | information. This is generally a good idea, so say Y. | |
382 | ||
383 | config BSD_PROCESS_ACCT_V3 | |
384 | bool "BSD Process Accounting version 3 file format" | |
385 | depends on BSD_PROCESS_ACCT | |
386 | default n | |
387 | help | |
388 | If you say Y here, the process accounting information is written | |
389 | in a new file format that also logs the process IDs of each | |
390 | process and it's parent. Note that this file format is incompatible | |
391 | with previous v0/v1/v2 file formats, so you will need updated tools | |
392 | for processing it. A preliminary version of these tools is available | |
37a4c940 | 393 | at <http://www.gnu.org/software/acct/>. |
1da177e4 | 394 | |
c757249a SN |
395 | config TASKSTATS |
396 | bool "Export task/process statistics through netlink (EXPERIMENTAL)" | |
397 | depends on NET | |
398 | default n | |
399 | help | |
400 | Export selected statistics for tasks/processes through the | |
401 | generic netlink interface. Unlike BSD process accounting, the | |
402 | statistics are available during the lifetime of tasks/processes as | |
403 | responses to commands. Like BSD accounting, they are sent to user | |
404 | space on task exit. | |
405 | ||
406 | Say N if unsure. | |
407 | ||
ca74e92b SN |
408 | config TASK_DELAY_ACCT |
409 | bool "Enable per-task delay accounting (EXPERIMENTAL)" | |
6f44993f | 410 | depends on TASKSTATS |
ca74e92b SN |
411 | help |
412 | Collect information on time spent by a task waiting for system | |
413 | resources like cpu, synchronous block I/O completion and swapping | |
414 | in pages. Such statistics can help in setting a task's priorities | |
415 | relative to other tasks for cpu, io, rss limits etc. | |
416 | ||
417 | Say N if unsure. | |
418 | ||
18f705f4 AD |
419 | config TASK_XACCT |
420 | bool "Enable extended accounting over taskstats (EXPERIMENTAL)" | |
421 | depends on TASKSTATS | |
422 | help | |
423 | Collect extended task accounting data and send the data | |
424 | to userland for processing over the taskstats interface. | |
425 | ||
426 | Say N if unsure. | |
427 | ||
428 | config TASK_IO_ACCOUNTING | |
429 | bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" | |
430 | depends on TASK_XACCT | |
431 | help | |
432 | Collect information on the number of bytes of storage I/O which this | |
433 | task has caused. | |
434 | ||
435 | Say N if unsure. | |
436 | ||
391dc69c | 437 | endmenu # "CPU/Task time and stats accounting" |
d9817ebe | 438 | |
c903ff83 MT |
439 | menu "RCU Subsystem" |
440 | ||
441 | choice | |
442 | prompt "RCU Implementation" | |
31c9a24e | 443 | default TREE_RCU |
c903ff83 | 444 | |
c903ff83 MT |
445 | config TREE_RCU |
446 | bool "Tree-based hierarchical RCU" | |
687d7a96 | 447 | depends on !PREEMPT && SMP |
c903ff83 MT |
448 | help |
449 | This option selects the RCU implementation that is | |
450 | designed for very large SMP system with hundreds or | |
c17ef453 PM |
451 | thousands of CPUs. It also scales down nicely to |
452 | smaller systems. | |
c903ff83 | 453 | |
f41d911f | 454 | config TREE_PREEMPT_RCU |
a57eb940 | 455 | bool "Preemptible tree-based hierarchical RCU" |
8008e129 | 456 | depends on PREEMPT && SMP |
f41d911f PM |
457 | help |
458 | This option selects the RCU implementation that is | |
459 | designed for very large SMP systems with hundreds or | |
460 | thousands of CPUs, but for which real-time response | |
bbe3eae8 PM |
461 | is also required. It also scales down nicely to |
462 | smaller systems. | |
f41d911f | 463 | |
9b1d82fa PM |
464 | config TINY_RCU |
465 | bool "UP-only small-memory-footprint RCU" | |
8008e129 | 466 | depends on !PREEMPT && !SMP |
9b1d82fa PM |
467 | help |
468 | This option selects the RCU implementation that is | |
469 | designed for UP systems from which real-time response | |
470 | is not required. This option greatly reduces the | |
471 | memory footprint of RCU. | |
472 | ||
a57eb940 PM |
473 | config TINY_PREEMPT_RCU |
474 | bool "Preemptible UP-only small-memory-footprint RCU" | |
8008e129 | 475 | depends on PREEMPT && !SMP |
a57eb940 PM |
476 | help |
477 | This option selects the RCU implementation that is designed | |
478 | for real-time UP systems. This option greatly reduces the | |
479 | memory footprint of RCU. | |
480 | ||
c903ff83 MT |
481 | endchoice |
482 | ||
a57eb940 PM |
483 | config PREEMPT_RCU |
484 | def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU ) | |
485 | help | |
486 | This option enables preemptible-RCU code that is common between | |
487 | the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations. | |
488 | ||
91d1aa43 FW |
489 | config CONTEXT_TRACKING |
490 | bool | |
491 | ||
2b1d5024 FW |
492 | config RCU_USER_QS |
493 | bool "Consider userspace as in RCU extended quiescent state" | |
91d1aa43 FW |
494 | depends on HAVE_CONTEXT_TRACKING && SMP |
495 | select CONTEXT_TRACKING | |
2b1d5024 FW |
496 | help |
497 | This option sets hooks on kernel / userspace boundaries and | |
498 | puts RCU in extended quiescent state when the CPU runs in | |
499 | userspace. It means that when a CPU runs in userspace, it is | |
500 | excluded from the global RCU state machine and thus doesn't | |
af71befa | 501 | try to keep the timer tick on for RCU. |
2b1d5024 | 502 | |
d677124b | 503 | Unless you want to hack and help the development of the full |
91d1aa43 | 504 | dynticks mode, you shouldn't enable this option. It also |
af71befa | 505 | adds unnecessary overhead. |
d677124b FW |
506 | |
507 | If unsure say N | |
508 | ||
91d1aa43 FW |
509 | config CONTEXT_TRACKING_FORCE |
510 | bool "Force context tracking" | |
511 | depends on CONTEXT_TRACKING | |
1fd2b442 | 512 | help |
91d1aa43 FW |
513 | Probe on user/kernel boundaries by default in order to |
514 | test the features that rely on it such as userspace RCU extended | |
515 | quiescent states. | |
516 | This test is there for debugging until we have a real user like the | |
517 | full dynticks mode. | |
d677124b | 518 | |
c903ff83 MT |
519 | config RCU_FANOUT |
520 | int "Tree-based hierarchical RCU fanout value" | |
521 | range 2 64 if 64BIT | |
522 | range 2 32 if !64BIT | |
f41d911f | 523 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
524 | default 64 if 64BIT |
525 | default 32 if !64BIT | |
526 | help | |
527 | This option controls the fanout of hierarchical implementations | |
528 | of RCU, allowing RCU to work efficiently on machines with | |
4d87ffad PM |
529 | large numbers of CPUs. This value must be at least the fourth |
530 | root of NR_CPUS, which allows NR_CPUS to be insanely large. | |
531 | The default value of RCU_FANOUT should be used for production | |
532 | systems, but if you are stress-testing the RCU implementation | |
533 | itself, small RCU_FANOUT values allow you to test large-system | |
534 | code paths on small(er) systems. | |
c903ff83 MT |
535 | |
536 | Select a specific number if testing RCU itself. | |
537 | Take the default if unsure. | |
538 | ||
8932a63d PM |
539 | config RCU_FANOUT_LEAF |
540 | int "Tree-based hierarchical RCU leaf-level fanout value" | |
541 | range 2 RCU_FANOUT if 64BIT | |
542 | range 2 RCU_FANOUT if !64BIT | |
543 | depends on TREE_RCU || TREE_PREEMPT_RCU | |
544 | default 16 | |
545 | help | |
546 | This option controls the leaf-level fanout of hierarchical | |
547 | implementations of RCU, and allows trading off cache misses | |
548 | against lock contention. Systems that synchronize their | |
549 | scheduling-clock interrupts for energy-efficiency reasons will | |
550 | want the default because the smaller leaf-level fanout keeps | |
551 | lock contention levels acceptably low. Very large systems | |
552 | (hundreds or thousands of CPUs) will instead want to set this | |
553 | value to the maximum value possible in order to reduce the | |
554 | number of cache misses incurred during RCU's grace-period | |
555 | initialization. These systems tend to run CPU-bound, and thus | |
556 | are not helped by synchronized interrupts, and thus tend to | |
557 | skew them, which reduces lock contention enough that large | |
558 | leaf-level fanouts work well. | |
559 | ||
560 | Select a specific number if testing RCU itself. | |
561 | ||
562 | Select the maximum permissible value for large systems. | |
563 | ||
564 | Take the default if unsure. | |
565 | ||
c903ff83 MT |
566 | config RCU_FANOUT_EXACT |
567 | bool "Disable tree-based hierarchical RCU auto-balancing" | |
f41d911f | 568 | depends on TREE_RCU || TREE_PREEMPT_RCU |
c903ff83 MT |
569 | default n |
570 | help | |
571 | This option forces use of the exact RCU_FANOUT value specified, | |
572 | regardless of imbalances in the hierarchy. This is useful for | |
573 | testing RCU itself, and might one day be useful on systems with | |
574 | strong NUMA behavior. | |
575 | ||
576 | Without RCU_FANOUT_EXACT, the code will balance the hierarchy. | |
577 | ||
578 | Say N if unsure. | |
579 | ||
8bd93a2c PM |
580 | config RCU_FAST_NO_HZ |
581 | bool "Accelerate last non-dyntick-idle CPU's grace periods" | |
b807fbff | 582 | depends on NO_HZ && SMP |
8bd93a2c PM |
583 | default n |
584 | help | |
ba49df47 PM |
585 | This option causes RCU to attempt to accelerate grace periods in |
586 | order to allow CPUs to enter dynticks-idle state more quickly. | |
587 | On the other hand, this option increases the overhead of the | |
588 | dynticks-idle checking, thus degrading scheduling latency. | |
589 | ||
590 | Say Y if energy efficiency is critically important, and you don't | |
591 | care about real-time response. | |
8bd93a2c PM |
592 | |
593 | Say N if you are unsure. | |
594 | ||
c903ff83 | 595 | config TREE_RCU_TRACE |
f41d911f | 596 | def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) |
c903ff83 MT |
597 | select DEBUG_FS |
598 | help | |
f41d911f PM |
599 | This option provides tracing for the TREE_RCU and |
600 | TREE_PREEMPT_RCU implementations, permitting Makefile to | |
601 | trivially select kernel/rcutree_trace.c. | |
c903ff83 | 602 | |
24278d14 PM |
603 | config RCU_BOOST |
604 | bool "Enable RCU priority boosting" | |
27f4d280 | 605 | depends on RT_MUTEXES && PREEMPT_RCU |
24278d14 PM |
606 | default n |
607 | help | |
608 | This option boosts the priority of preempted RCU readers that | |
609 | block the current preemptible RCU grace period for too long. | |
610 | This option also prevents heavy loads from blocking RCU | |
611 | callback invocation for all flavors of RCU. | |
612 | ||
613 | Say Y here if you are working with real-time apps or heavy loads | |
614 | Say N here if you are unsure. | |
615 | ||
616 | config RCU_BOOST_PRIO | |
617 | int "Real-time priority to boost RCU readers to" | |
618 | range 1 99 | |
619 | depends on RCU_BOOST | |
620 | default 1 | |
621 | help | |
c9336643 PM |
622 | This option specifies the real-time priority to which long-term |
623 | preempted RCU readers are to be boosted. If you are working | |
624 | with a real-time application that has one or more CPU-bound | |
625 | threads running at a real-time priority level, you should set | |
626 | RCU_BOOST_PRIO to a priority higher then the highest-priority | |
627 | real-time CPU-bound thread. The default RCU_BOOST_PRIO value | |
628 | of 1 is appropriate in the common case, which is real-time | |
629 | applications that do not have any CPU-bound threads. | |
630 | ||
631 | Some real-time applications might not have a single real-time | |
632 | thread that saturates a given CPU, but instead might have | |
633 | multiple real-time threads that, taken together, fully utilize | |
634 | that CPU. In this case, you should set RCU_BOOST_PRIO to | |
635 | a priority higher than the lowest-priority thread that is | |
636 | conspiring to prevent the CPU from running any non-real-time | |
637 | tasks. For example, if one thread at priority 10 and another | |
638 | thread at priority 5 are between themselves fully consuming | |
639 | the CPU time on a given CPU, then RCU_BOOST_PRIO should be | |
640 | set to priority 6 or higher. | |
24278d14 PM |
641 | |
642 | Specify the real-time priority, or take the default if unsure. | |
643 | ||
644 | config RCU_BOOST_DELAY | |
645 | int "Milliseconds to delay boosting after RCU grace-period start" | |
646 | range 0 3000 | |
647 | depends on RCU_BOOST | |
648 | default 500 | |
649 | help | |
650 | This option specifies the time to wait after the beginning of | |
651 | a given grace period before priority-boosting preempted RCU | |
652 | readers blocking that grace period. Note that any RCU reader | |
653 | blocking an expedited RCU grace period is boosted immediately. | |
654 | ||
655 | Accept the default if unsure. | |
656 | ||
3fbfbf7a PM |
657 | config RCU_NOCB_CPU |
658 | bool "Offload RCU callback processing from boot-selected CPUs" | |
659 | depends on TREE_RCU || TREE_PREEMPT_RCU | |
660 | default n | |
661 | help | |
662 | Use this option to reduce OS jitter for aggressive HPC or | |
663 | real-time workloads. It can also be used to offload RCU | |
664 | callback invocation to energy-efficient CPUs in battery-powered | |
665 | asymmetric multiprocessors. | |
666 | ||
667 | This option offloads callback invocation from the set of | |
668 | CPUs specified at boot time by the rcu_nocbs parameter. | |
669 | For each such CPU, a kthread ("rcuoN") will be created to | |
670 | invoke callbacks, where the "N" is the CPU being offloaded. | |
671 | Nothing prevents this kthread from running on the specified | |
672 | CPUs, but (1) the kthreads may be preempted between each | |
673 | callback, and (2) affinity or cgroups can be used to force | |
674 | the kthreads to run on whatever set of CPUs is desired. | |
675 | ||
676 | Say Y here if you want reduced OS jitter on selected CPUs. | |
677 | Say N here if you are unsure. | |
678 | ||
c903ff83 MT |
679 | endmenu # "RCU Subsystem" |
680 | ||
1da177e4 | 681 | config IKCONFIG |
f2443ab6 | 682 | tristate "Kernel .config support" |
1da177e4 LT |
683 | ---help--- |
684 | This option enables the complete Linux kernel ".config" file | |
685 | contents to be saved in the kernel. It provides documentation | |
686 | of which kernel options are used in a running kernel or in an | |
687 | on-disk kernel. This information can be extracted from the kernel | |
688 | image file with the script scripts/extract-ikconfig and used as | |
689 | input to rebuild the current kernel or to build another kernel. | |
690 | It can also be extracted from a running kernel by reading | |
691 | /proc/config.gz if enabled (below). | |
692 | ||
693 | config IKCONFIG_PROC | |
694 | bool "Enable access to .config through /proc/config.gz" | |
695 | depends on IKCONFIG && PROC_FS | |
696 | ---help--- | |
697 | This option enables access to the kernel configuration file | |
698 | through /proc/config.gz. | |
699 | ||
794543a2 AJS |
700 | config LOG_BUF_SHIFT |
701 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" | |
702 | range 12 21 | |
f17a32e9 | 703 | default 17 |
794543a2 AJS |
704 | help |
705 | Select kernel log buffer size as a power of 2. | |
f17a32e9 AB |
706 | Examples: |
707 | 17 => 128 KB | |
708 | 16 => 64 KB | |
709 | 15 => 32 KB | |
710 | 14 => 16 KB | |
794543a2 AJS |
711 | 13 => 8 KB |
712 | 12 => 4 KB | |
713 | ||
a5574cf6 IM |
714 | # |
715 | # Architectures with an unreliable sched_clock() should select this: | |
716 | # | |
717 | config HAVE_UNSTABLE_SCHED_CLOCK | |
718 | bool | |
719 | ||
be3a7284 AA |
720 | # |
721 | # For architectures that want to enable the support for NUMA-affine scheduler | |
722 | # balancing logic: | |
723 | # | |
724 | config ARCH_SUPPORTS_NUMA_BALANCING | |
725 | bool | |
726 | ||
727 | # For architectures that (ab)use NUMA to represent different memory regions | |
728 | # all cpu-local but of different latencies, such as SuperH. | |
729 | # | |
730 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
731 | bool | |
732 | ||
733 | # | |
734 | # For architectures that are willing to define _PAGE_NUMA as _PAGE_PROTNONE | |
735 | config ARCH_WANTS_PROT_NUMA_PROT_NONE | |
736 | bool | |
737 | ||
738 | config ARCH_USES_NUMA_PROT_NONE | |
739 | bool | |
740 | default y | |
741 | depends on ARCH_WANTS_PROT_NUMA_PROT_NONE | |
742 | depends on NUMA_BALANCING | |
743 | ||
1a687c2e MG |
744 | config NUMA_BALANCING_DEFAULT_ENABLED |
745 | bool "Automatically enable NUMA aware memory/task placement" | |
746 | default y | |
747 | depends on NUMA_BALANCING | |
748 | help | |
749 | If set, autonumic NUMA balancing will be enabled if running on a NUMA | |
750 | machine. | |
751 | ||
be3a7284 AA |
752 | config NUMA_BALANCING |
753 | bool "Memory placement aware NUMA scheduler" | |
be3a7284 AA |
754 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
755 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY | |
756 | depends on SMP && NUMA && MIGRATION | |
757 | help | |
758 | This option adds support for automatic NUMA aware memory/task placement. | |
759 | The mechanism is quite primitive and is based on migrating memory when | |
760 | it is references to the node the task is running on. | |
761 | ||
762 | This system will be inactive on UMA systems. | |
763 | ||
23964d2d LZ |
764 | menuconfig CGROUPS |
765 | boolean "Control Group support" | |
0dea1168 | 766 | depends on EVENTFD |
5cdc38f9 | 767 | help |
23964d2d | 768 | This option adds support for grouping sets of processes together, for |
5cdc38f9 KH |
769 | use with process control subsystems such as Cpusets, CFS, memory |
770 | controls or device isolation. | |
771 | See | |
5cdc38f9 | 772 | - Documentation/scheduler/sched-design-CFS.txt (CFS) |
45ce80fb LZ |
773 | - Documentation/cgroups/ (features for grouping, isolation |
774 | and resource control) | |
5cdc38f9 KH |
775 | |
776 | Say N if unsure. | |
777 | ||
23964d2d LZ |
778 | if CGROUPS |
779 | ||
5cdc38f9 KH |
780 | config CGROUP_DEBUG |
781 | bool "Example debug cgroup subsystem" | |
5cdc38f9 KH |
782 | default n |
783 | help | |
784 | This option enables a simple cgroup subsystem that | |
785 | exports useful debugging information about the cgroups | |
23964d2d | 786 | framework. |
5cdc38f9 | 787 | |
23964d2d | 788 | Say N if unsure. |
5cdc38f9 | 789 | |
5cdc38f9 | 790 | config CGROUP_FREEZER |
23964d2d | 791 | bool "Freezer cgroup subsystem" |
23964d2d LZ |
792 | help |
793 | Provides a way to freeze and unfreeze all tasks in a | |
5cdc38f9 KH |
794 | cgroup. |
795 | ||
796 | config CGROUP_DEVICE | |
797 | bool "Device controller for cgroups" | |
5cdc38f9 KH |
798 | help |
799 | Provides a cgroup implementing whitelists for devices which | |
800 | a process in the cgroup can mknod or open. | |
801 | ||
802 | config CPUSETS | |
803 | bool "Cpuset support" | |
5cdc38f9 KH |
804 | help |
805 | This option will let you create and manage CPUSETs which | |
806 | allow dynamically partitioning a system into sets of CPUs and | |
807 | Memory Nodes and assigning tasks to run only within those sets. | |
808 | This is primarily useful on large SMP or NUMA systems. | |
809 | ||
810 | Say N if unsure. | |
811 | ||
23964d2d LZ |
812 | config PROC_PID_CPUSET |
813 | bool "Include legacy /proc/<pid>/cpuset file" | |
814 | depends on CPUSETS | |
815 | default y | |
816 | ||
d842de87 SV |
817 | config CGROUP_CPUACCT |
818 | bool "Simple CPU accounting cgroup subsystem" | |
d842de87 SV |
819 | help |
820 | Provides a simple Resource Controller for monitoring the | |
23964d2d | 821 | total CPU consumed by the tasks in a cgroup. |
d842de87 | 822 | |
e552b661 PE |
823 | config RESOURCE_COUNTERS |
824 | bool "Resource counters" | |
825 | help | |
826 | This option enables controller independent resource accounting | |
23964d2d | 827 | infrastructure that works with cgroups. |
e552b661 | 828 | |
c255a458 | 829 | config MEMCG |
00f0b825 | 830 | bool "Memory Resource Controller for Control Groups" |
79ae9c29 | 831 | depends on RESOURCE_COUNTERS |
cf475ad2 | 832 | select MM_OWNER |
00f0b825 | 833 | help |
84ad6d70 | 834 | Provides a memory resource controller that manages both anonymous |
21acb9ca | 835 | memory and page cache. (See Documentation/cgroups/memory.txt) |
00f0b825 BS |
836 | |
837 | Note that setting this option increases fixed memory overhead | |
84ad6d70 KH |
838 | associated with each page of memory in the system. By this, |
839 | 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory | |
840 | usage tracking struct at boot. Total amount of this is printed out | |
841 | at boot. | |
00f0b825 BS |
842 | |
843 | Only enable when you're ok with these trade offs and really | |
84ad6d70 KH |
844 | sure you need the memory resource controller. Even when you enable |
845 | this, you can set "cgroup_disable=memory" at your boot option to | |
846 | disable memory resource controller and you can avoid overheads. | |
c9d5409f | 847 | (and lose benefits of memory resource controller) |
00f0b825 | 848 | |
cf475ad2 BS |
849 | This config option also selects MM_OWNER config option, which |
850 | could in turn add some fork/exit overhead. | |
851 | ||
c255a458 | 852 | config MEMCG_SWAP |
65e0e811 | 853 | bool "Memory Resource Controller Swap Extension" |
c255a458 | 854 | depends on MEMCG && SWAP |
c077719b KH |
855 | help |
856 | Add swap management feature to memory resource controller. When you | |
857 | enable this, you can limit mem+swap usage per cgroup. In other words, | |
858 | when you disable this, memory resource controller has no cares to | |
859 | usage of swap...a process can exhaust all of the swap. This extension | |
860 | is useful when you want to avoid exhaustion swap but this itself | |
861 | adds more overheads and consumes memory for remembering information. | |
862 | Especially if you use 32bit system or small memory system, please | |
863 | be careful about enabling this. When memory resource controller | |
864 | is disabled by boot option, this will be automatically disabled and | |
865 | there will be no overhead from this. Even when you set this config=y, | |
00a66d29 | 866 | if boot option "swapaccount=0" is set, swap will not be accounted. |
627991a2 KH |
867 | Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page |
868 | size is 4096bytes, 512k per 1Gbytes of swap. | |
c255a458 | 869 | config MEMCG_SWAP_ENABLED |
a42c390c | 870 | bool "Memory Resource Controller Swap Extension enabled by default" |
c255a458 | 871 | depends on MEMCG_SWAP |
a42c390c MH |
872 | default y |
873 | help | |
874 | Memory Resource Controller Swap Extension comes with its price in | |
875 | a bigger memory consumption. General purpose distribution kernels | |
43d547f9 | 876 | which want to enable the feature but keep it disabled by default |
a42c390c MH |
877 | and let the user enable it by swapaccount boot command line |
878 | parameter should have this option unselected. | |
879 | For those who want to have the feature enabled by default should | |
880 | select this option (if, for some reason, they need to disable it | |
00a66d29 | 881 | then swapaccount=0 does the trick). |
c255a458 | 882 | config MEMCG_KMEM |
e5671dfa | 883 | bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)" |
c255a458 | 884 | depends on MEMCG && EXPERIMENTAL |
510fc4e1 | 885 | depends on SLUB || SLAB |
e5671dfa GC |
886 | help |
887 | The Kernel Memory extension for Memory Resource Controller can limit | |
888 | the amount of memory used by kernel objects in the system. Those are | |
889 | fundamentally different from the entities handled by the standard | |
890 | Memory Controller, which are page-based, and can be swapped. Users of | |
891 | the kmem extension can use it to guarantee that no group of processes | |
892 | will ever exhaust kernel resources alone. | |
c077719b | 893 | |
2bc64a20 AK |
894 | config CGROUP_HUGETLB |
895 | bool "HugeTLB Resource Controller for Control Groups" | |
896 | depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL | |
897 | default n | |
898 | help | |
899 | Provides a cgroup Resource Controller for HugeTLB pages. | |
900 | When you enable this, you can put a per cgroup limit on HugeTLB usage. | |
901 | The limit is enforced during page fault. Since HugeTLB doesn't | |
902 | support page reclaim, enforcing the limit at page fault time implies | |
903 | that, the application will get SIGBUS signal if it tries to access | |
904 | HugeTLB pages beyond its limit. This requires the application to know | |
905 | beforehand how much HugeTLB pages it would require for its use. The | |
906 | control group is tracked in the third page lru pointer. This means | |
907 | that we cannot use the controller with huge page less than 3 pages. | |
908 | ||
e5d1367f SE |
909 | config CGROUP_PERF |
910 | bool "Enable perf_event per-cpu per-container group (cgroup) monitoring" | |
911 | depends on PERF_EVENTS && CGROUPS | |
912 | help | |
913 | This option extends the per-cpu mode to restrict monitoring to | |
2d0f2520 | 914 | threads which belong to the cgroup specified and run on the |
e5d1367f SE |
915 | designated cpu. |
916 | ||
917 | Say N if unsure. | |
918 | ||
7c941438 DG |
919 | menuconfig CGROUP_SCHED |
920 | bool "Group CPU scheduler" | |
7c941438 DG |
921 | default n |
922 | help | |
923 | This feature lets CPU scheduler recognize task groups and control CPU | |
924 | bandwidth allocation to such task groups. It uses cgroups to group | |
925 | tasks. | |
926 | ||
927 | if CGROUP_SCHED | |
928 | config FAIR_GROUP_SCHED | |
929 | bool "Group scheduling for SCHED_OTHER" | |
930 | depends on CGROUP_SCHED | |
931 | default CGROUP_SCHED | |
932 | ||
ab84d31e PT |
933 | config CFS_BANDWIDTH |
934 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" | |
935 | depends on EXPERIMENTAL | |
936 | depends on FAIR_GROUP_SCHED | |
937 | default n | |
938 | help | |
939 | This option allows users to define CPU bandwidth rates (limits) for | |
940 | tasks running within the fair group scheduler. Groups with no limit | |
941 | set are considered to be unconstrained and will run with no | |
942 | restriction. | |
943 | See tip/Documentation/scheduler/sched-bwc.txt for more information. | |
944 | ||
7c941438 DG |
945 | config RT_GROUP_SCHED |
946 | bool "Group scheduling for SCHED_RR/FIFO" | |
947 | depends on EXPERIMENTAL | |
948 | depends on CGROUP_SCHED | |
949 | default n | |
950 | help | |
951 | This feature lets you explicitly allocate real CPU bandwidth | |
32bd7eb5 | 952 | to task groups. If enabled, it will also make it impossible to |
7c941438 DG |
953 | schedule realtime tasks for non-root users until you allocate |
954 | realtime bandwidth for them. | |
955 | See Documentation/scheduler/sched-rt-group.txt for more information. | |
956 | ||
957 | endif #CGROUP_SCHED | |
958 | ||
afc24d49 | 959 | config BLK_CGROUP |
32e380ae | 960 | bool "Block IO controller" |
79ae9c29 | 961 | depends on BLOCK |
afc24d49 VG |
962 | default n |
963 | ---help--- | |
964 | Generic block IO controller cgroup interface. This is the common | |
965 | cgroup interface which should be used by various IO controlling | |
966 | policies. | |
967 | ||
968 | Currently, CFQ IO scheduler uses it to recognize task groups and | |
969 | control disk bandwidth allocation (proportional time slice allocation) | |
e43473b7 VG |
970 | to such task groups. It is also used by bio throttling logic in |
971 | block layer to implement upper limit in IO rates on a device. | |
afc24d49 VG |
972 | |
973 | This option only enables generic Block IO controller infrastructure. | |
e43473b7 | 974 | One needs to also enable actual IO controlling logic/policy. For |
79e2e759 MW |
975 | enabling proportional weight division of disk bandwidth in CFQ, set |
976 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set | |
c5e0591a | 977 | CONFIG_BLK_DEV_THROTTLING=y. |
afc24d49 VG |
978 | |
979 | See Documentation/cgroups/blkio-controller.txt for more information. | |
980 | ||
981 | config DEBUG_BLK_CGROUP | |
982 | bool "Enable Block IO controller debugging" | |
983 | depends on BLK_CGROUP | |
984 | default n | |
985 | ---help--- | |
986 | Enable some debugging help. Currently it exports additional stat | |
987 | files in a cgroup which can be useful for debugging. | |
988 | ||
23964d2d | 989 | endif # CGROUPS |
c077719b | 990 | |
067bce1a CG |
991 | config CHECKPOINT_RESTORE |
992 | bool "Checkpoint/restore support" if EXPERT | |
993 | default n | |
994 | help | |
995 | Enables additional kernel features in a sake of checkpoint/restore. | |
996 | In particular it adds auxiliary prctl codes to setup process text, | |
997 | data and heap segment sizes, and a few additional /proc filesystem | |
998 | entries. | |
999 | ||
1000 | If unsure, say N here. | |
1001 | ||
8dd2a82c | 1002 | menuconfig NAMESPACES |
6a108a14 DR |
1003 | bool "Namespaces support" if EXPERT |
1004 | default !EXPERT | |
c5289a69 PE |
1005 | help |
1006 | Provides the way to make tasks work with different objects using | |
1007 | the same id. For example same IPC id may refer to different objects | |
1008 | or same user id or pid may refer to different tasks when used in | |
1009 | different namespaces. | |
1010 | ||
8dd2a82c DL |
1011 | if NAMESPACES |
1012 | ||
58bfdd6d PE |
1013 | config UTS_NS |
1014 | bool "UTS namespace" | |
17a6d441 | 1015 | default y |
58bfdd6d PE |
1016 | help |
1017 | In this namespace tasks see different info provided with the | |
1018 | uname() system call | |
1019 | ||
ae5e1b22 PE |
1020 | config IPC_NS |
1021 | bool "IPC namespace" | |
8dd2a82c | 1022 | depends on (SYSVIPC || POSIX_MQUEUE) |
17a6d441 | 1023 | default y |
ae5e1b22 PE |
1024 | help |
1025 | In this namespace tasks work with IPC ids which correspond to | |
614b84cf | 1026 | different IPC objects in different namespaces. |
ae5e1b22 | 1027 | |
aee16ce7 PE |
1028 | config USER_NS |
1029 | bool "User namespace (EXPERIMENTAL)" | |
8dd2a82c | 1030 | depends on EXPERIMENTAL |
e1c972b6 | 1031 | depends on UIDGID_CONVERTED |
5673a94c | 1032 | select UIDGID_STRICT_TYPE_CHECKS |
e1c972b6 | 1033 | |
5673a94c | 1034 | default n |
aee16ce7 PE |
1035 | help |
1036 | This allows containers, i.e. vservers, to use user namespaces | |
1037 | to provide different user info for different servers. | |
1038 | If unsure, say N. | |
1039 | ||
74bd59bb | 1040 | config PID_NS |
9bd38c2c | 1041 | bool "PID Namespaces" |
17a6d441 | 1042 | default y |
74bd59bb | 1043 | help |
12d2b8f9 | 1044 | Support process id namespaces. This allows having multiple |
692105b8 | 1045 | processes with the same pid as long as they are in different |
74bd59bb PE |
1046 | pid namespaces. This is a building block of containers. |
1047 | ||
d6eb633f MH |
1048 | config NET_NS |
1049 | bool "Network namespace" | |
8dd2a82c | 1050 | depends on NET |
17a6d441 | 1051 | default y |
d6eb633f MH |
1052 | help |
1053 | Allow user space to create what appear to be multiple instances | |
1054 | of the network stack. | |
1055 | ||
8dd2a82c DL |
1056 | endif # NAMESPACES |
1057 | ||
e1c972b6 EB |
1058 | config UIDGID_CONVERTED |
1059 | # True if all of the selected software conmponents are known | |
1060 | # to have uid_t and gid_t converted to kuid_t and kgid_t | |
1061 | # where appropriate and are otherwise safe to use with | |
1062 | # the user namespace. | |
1063 | bool | |
1064 | default y | |
1065 | ||
e1c972b6 | 1066 | # Networking |
e1c972b6 | 1067 | depends on NET_9P = n |
e1c972b6 EB |
1068 | |
1069 | # Filesystems | |
e1c972b6 | 1070 | depends on 9P_FS = n |
e1c972b6 | 1071 | depends on AFS_FS = n |
e1c972b6 EB |
1072 | depends on CEPH_FS = n |
1073 | depends on CIFS = n | |
1074 | depends on CODA_FS = n | |
e1c972b6 | 1075 | depends on GFS2_FS = n |
e1c972b6 EB |
1076 | depends on NCP_FS = n |
1077 | depends on NFSD = n | |
1078 | depends on NFS_FS = n | |
e1c972b6 | 1079 | depends on OCFS2_FS = n |
e1c972b6 EB |
1080 | depends on XFS_FS = n |
1081 | ||
5673a94c EB |
1082 | config UIDGID_STRICT_TYPE_CHECKS |
1083 | bool "Require conversions between uid/gids and their internal representation" | |
e1c972b6 | 1084 | depends on UIDGID_CONVERTED |
5673a94c EB |
1085 | default n |
1086 | help | |
1087 | While the nececessary conversions are being added to all subsystems this option allows | |
1088 | the code to continue to build for unconverted subsystems. | |
1089 | ||
1090 | Say Y here if you want the strict type checking enabled | |
1091 | ||
5091faa4 MG |
1092 | config SCHED_AUTOGROUP |
1093 | bool "Automatic process group scheduling" | |
1094 | select EVENTFD | |
1095 | select CGROUPS | |
1096 | select CGROUP_SCHED | |
1097 | select FAIR_GROUP_SCHED | |
1098 | help | |
1099 | This option optimizes the scheduler for common desktop workloads by | |
1100 | automatically creating and populating task groups. This separation | |
1101 | of workloads isolates aggressive CPU burners (like build jobs) from | |
1102 | desktop applications. Task group autogeneration is currently based | |
1103 | upon task session. | |
1104 | ||
7af37bec DL |
1105 | config MM_OWNER |
1106 | bool | |
1107 | ||
1108 | config SYSFS_DEPRECATED | |
5d6a4ea5 | 1109 | bool "Enable deprecated sysfs features to support old userspace tools" |
7af37bec DL |
1110 | depends on SYSFS |
1111 | default n | |
1112 | help | |
1113 | This option adds code that switches the layout of the "block" class | |
1114 | devices, to not show up in /sys/class/block/, but only in | |
1115 | /sys/block/. | |
1116 | ||
1117 | This switch is only active when the sysfs.deprecated=1 boot option is | |
1118 | passed or the SYSFS_DEPRECATED_V2 option is set. | |
1119 | ||
1120 | This option allows new kernels to run on old distributions and tools, | |
1121 | which might get confused by /sys/class/block/. Since 2007/2008 all | |
1122 | major distributions and tools handle this just fine. | |
1123 | ||
1124 | Recent distributions and userspace tools after 2009/2010 depend on | |
1125 | the existence of /sys/class/block/, and will not work with this | |
1126 | option enabled. | |
1127 | ||
1128 | Only if you are using a new kernel on an old distribution, you might | |
1129 | need to say Y here. | |
1130 | ||
1131 | config SYSFS_DEPRECATED_V2 | |
5d6a4ea5 | 1132 | bool "Enable deprecated sysfs features by default" |
7af37bec DL |
1133 | default n |
1134 | depends on SYSFS | |
1135 | depends on SYSFS_DEPRECATED | |
1136 | help | |
1137 | Enable deprecated sysfs by default. | |
1138 | ||
1139 | See the CONFIG_SYSFS_DEPRECATED option for more details about this | |
1140 | option. | |
1141 | ||
1142 | Only if you are using a new kernel on an old distribution, you might | |
1143 | need to say Y here. Even then, odds are you would not need it | |
1144 | enabled, you can always pass the boot option if absolutely necessary. | |
1145 | ||
1146 | config RELAY | |
1147 | bool "Kernel->user space relay support (formerly relayfs)" | |
1148 | help | |
1149 | This option enables support for relay interface support in | |
1150 | certain file systems (such as debugfs). | |
1151 | It is designed to provide an efficient mechanism for tools and | |
1152 | facilities to relay large amounts of data from kernel space to | |
1153 | user space. | |
1154 | ||
1155 | If unsure, say N. | |
1156 | ||
f991633d DG |
1157 | config BLK_DEV_INITRD |
1158 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" | |
1159 | depends on BROKEN || !FRV | |
1160 | help | |
1161 | The initial RAM filesystem is a ramfs which is loaded by the | |
1162 | boot loader (loadlin or lilo) and that is mounted as root | |
1163 | before the normal boot procedure. It is typically used to | |
1164 | load modules needed to mount the "real" root file system, | |
1165 | etc. See <file:Documentation/initrd.txt> for details. | |
1166 | ||
1167 | If RAM disk support (BLK_DEV_RAM) is also included, this | |
1168 | also enables initial RAM disk (initrd) support and adds | |
1169 | 15 Kbytes (more on some other architectures) to the kernel size. | |
1170 | ||
1171 | If unsure say Y. | |
1172 | ||
c33df4ea JPS |
1173 | if BLK_DEV_INITRD |
1174 | ||
dbec4866 SR |
1175 | source "usr/Kconfig" |
1176 | ||
c33df4ea JPS |
1177 | endif |
1178 | ||
c45b4f1f | 1179 | config CC_OPTIMIZE_FOR_SIZE |
96fffeb4 | 1180 | bool "Optimize for size" |
c45b4f1f LT |
1181 | help |
1182 | Enabling this option will pass "-Os" instead of "-O2" to gcc | |
1183 | resulting in a smaller kernel. | |
1184 | ||
775a7229 | 1185 | If unsure, say Y. |
c45b4f1f | 1186 | |
0847062a RD |
1187 | config SYSCTL |
1188 | bool | |
1189 | ||
b943c460 RD |
1190 | config ANON_INODES |
1191 | bool | |
1192 | ||
6a108a14 DR |
1193 | menuconfig EXPERT |
1194 | bool "Configure standard kernel features (expert users)" | |
f505c553 JT |
1195 | # Unhide debug options, to make the on-by-default options visible |
1196 | select DEBUG_KERNEL | |
1da177e4 LT |
1197 | help |
1198 | This option allows certain base kernel options and settings | |
1199 | to be disabled or tweaked. This is for specialized | |
1200 | environments which can tolerate a "non-standard" kernel. | |
1201 | Only use this if you really know what you are doing. | |
1202 | ||
af1839eb CM |
1203 | config HAVE_UID16 |
1204 | bool | |
1205 | ||
ae81f9e3 | 1206 | config UID16 |
6a108a14 | 1207 | bool "Enable 16-bit UID system calls" if EXPERT |
af1839eb | 1208 | depends on HAVE_UID16 |
ae81f9e3 CE |
1209 | default y |
1210 | help | |
1211 | This enables the legacy 16-bit UID syscall wrappers. | |
1212 | ||
b89a8171 | 1213 | config SYSCTL_SYSCALL |
6a108a14 | 1214 | bool "Sysctl syscall support" if EXPERT |
26a7034b | 1215 | depends on PROC_SYSCTL |
c736de60 | 1216 | default n |
b89a8171 | 1217 | select SYSCTL |
ae81f9e3 | 1218 | ---help--- |
13bb7e37 EB |
1219 | sys_sysctl uses binary paths that have been found challenging |
1220 | to properly maintain and use. The interface in /proc/sys | |
1221 | using paths with ascii names is now the primary path to this | |
1222 | information. | |
b89a8171 | 1223 | |
13bb7e37 EB |
1224 | Almost nothing using the binary sysctl interface so if you are |
1225 | trying to save some space it is probably safe to disable this, | |
1226 | making your kernel marginally smaller. | |
b89a8171 | 1227 | |
c736de60 | 1228 | If unsure say N here. |
ae81f9e3 | 1229 | |
7ac57a89 CM |
1230 | config SYSCTL_EXCEPTION_TRACE |
1231 | bool | |
1232 | help | |
1233 | Enable support for /proc/sys/debug/exception-trace. | |
1234 | ||
1da177e4 | 1235 | config KALLSYMS |
6a108a14 | 1236 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
1da177e4 LT |
1237 | default y |
1238 | help | |
1239 | Say Y here to let the kernel print out symbolic crash information and | |
1240 | symbolic stack backtraces. This increases the size of the kernel | |
1241 | somewhat, as all symbols have to be loaded into the kernel image. | |
1242 | ||
1243 | config KALLSYMS_ALL | |
1244 | bool "Include all symbols in kallsyms" | |
1245 | depends on DEBUG_KERNEL && KALLSYMS | |
1246 | help | |
71a83ec7 AB |
1247 | Normally kallsyms only contains the symbols of functions for nicer |
1248 | OOPS messages and backtraces (i.e., symbols from the text and inittext | |
1249 | sections). This is sufficient for most cases. And only in very rare | |
1250 | cases (e.g., when a debugger is used) all symbols are required (e.g., | |
1251 | names of variables from the data sections, etc). | |
1252 | ||
1253 | This option makes sure that all symbols are loaded into the kernel | |
1254 | image (i.e., symbols from all sections) in cost of increased kernel | |
1255 | size (depending on the kernel configuration, it may be 300KiB or | |
1256 | something like this). | |
1257 | ||
1258 | Say N unless you really need all symbols. | |
d59745ce | 1259 | |
712f47ce | 1260 | config HOTPLUG |
45f035ab | 1261 | def_bool y |
712f47ce | 1262 | |
d59745ce MM |
1263 | config PRINTK |
1264 | default y | |
6a108a14 | 1265 | bool "Enable support for printk" if EXPERT |
d59745ce MM |
1266 | help |
1267 | This option enables normal printk support. Removing it | |
1268 | eliminates most of the message strings from the kernel image | |
1269 | and makes the kernel more or less silent. As this makes it | |
1270 | very difficult to diagnose system problems, saying N here is | |
1271 | strongly discouraged. | |
1272 | ||
c8538a7a | 1273 | config BUG |
6a108a14 | 1274 | bool "BUG() support" if EXPERT |
c8538a7a MM |
1275 | default y |
1276 | help | |
1277 | Disabling this option eliminates support for BUG and WARN, reducing | |
1278 | the size of your kernel image and potentially quietly ignoring | |
1279 | numerous fatal conditions. You should only consider disabling this | |
1280 | option for embedded systems with no facilities for reporting errors. | |
1281 | Just say Y. | |
1282 | ||
708e9a79 | 1283 | config ELF_CORE |
046d662f | 1284 | depends on COREDUMP |
708e9a79 | 1285 | default y |
6a108a14 | 1286 | bool "Enable ELF core dumps" if EXPERT |
708e9a79 MM |
1287 | help |
1288 | Enable support for generating core dumps. Disabling saves about 4k. | |
1289 | ||
8761f1ab | 1290 | |
e5e1d3cb | 1291 | config PCSPKR_PLATFORM |
6a108a14 | 1292 | bool "Enable PC-Speaker support" if EXPERT |
8761f1ab | 1293 | depends on HAVE_PCSPKR_PLATFORM |
15f304b6 | 1294 | select I8253_LOCK |
e5e1d3cb SS |
1295 | default y |
1296 | help | |
1297 | This option allows to disable the internal PC-Speaker | |
1298 | support, saving some memory. | |
1299 | ||
8761f1ab RB |
1300 | config HAVE_PCSPKR_PLATFORM |
1301 | bool | |
1302 | ||
1da177e4 LT |
1303 | config BASE_FULL |
1304 | default y | |
6a108a14 | 1305 | bool "Enable full-sized data structures for core" if EXPERT |
1da177e4 LT |
1306 | help |
1307 | Disabling this option reduces the size of miscellaneous core | |
1308 | kernel data structures. This saves memory on small machines, | |
1309 | but may reduce performance. | |
1310 | ||
1311 | config FUTEX | |
6a108a14 | 1312 | bool "Enable futex support" if EXPERT |
1da177e4 | 1313 | default y |
23f78d4a | 1314 | select RT_MUTEXES |
1da177e4 LT |
1315 | help |
1316 | Disabling this option will cause the kernel to be built without | |
1317 | support for "fast userspace mutexes". The resulting kernel may not | |
1318 | run glibc-based applications correctly. | |
1319 | ||
1320 | config EPOLL | |
6a108a14 | 1321 | bool "Enable eventpoll support" if EXPERT |
1da177e4 | 1322 | default y |
448e3cee | 1323 | select ANON_INODES |
1da177e4 LT |
1324 | help |
1325 | Disabling this option will cause the kernel to be built without | |
1326 | support for epoll family of system calls. | |
1327 | ||
fba2afaa | 1328 | config SIGNALFD |
6a108a14 | 1329 | bool "Enable signalfd() system call" if EXPERT |
448e3cee | 1330 | select ANON_INODES |
fba2afaa DL |
1331 | default y |
1332 | help | |
1333 | Enable the signalfd() system call that allows to receive signals | |
1334 | on a file descriptor. | |
1335 | ||
1336 | If unsure, say Y. | |
1337 | ||
b215e283 | 1338 | config TIMERFD |
6a108a14 | 1339 | bool "Enable timerfd() system call" if EXPERT |
448e3cee | 1340 | select ANON_INODES |
b215e283 DL |
1341 | default y |
1342 | help | |
1343 | Enable the timerfd() system call that allows to receive timer | |
1344 | events on a file descriptor. | |
1345 | ||
1346 | If unsure, say Y. | |
1347 | ||
e1ad7468 | 1348 | config EVENTFD |
6a108a14 | 1349 | bool "Enable eventfd() system call" if EXPERT |
448e3cee | 1350 | select ANON_INODES |
e1ad7468 DL |
1351 | default y |
1352 | help | |
1353 | Enable the eventfd() system call that allows to receive both | |
1354 | kernel notification (ie. KAIO) or userspace notifications. | |
1355 | ||
1356 | If unsure, say Y. | |
1357 | ||
1da177e4 | 1358 | config SHMEM |
6a108a14 | 1359 | bool "Use full shmem filesystem" if EXPERT |
1da177e4 LT |
1360 | default y |
1361 | depends on MMU | |
1362 | help | |
1363 | The shmem is an internal filesystem used to manage shared memory. | |
1364 | It is backed by swap and manages resource limits. It is also exported | |
1365 | to userspace as tmpfs if TMPFS is enabled. Disabling this | |
1366 | option replaces shmem and tmpfs with the much simpler ramfs code, | |
1367 | which may be appropriate on small systems without swap. | |
1368 | ||
ebf3f09c | 1369 | config AIO |
6a108a14 | 1370 | bool "Enable AIO support" if EXPERT |
ebf3f09c TP |
1371 | default y |
1372 | help | |
1373 | This option enables POSIX asynchronous I/O which may by used | |
1374 | by some high performance threaded applications. Disabling | |
1375 | this option saves about 7k. | |
1376 | ||
6befe5f6 RD |
1377 | config EMBEDDED |
1378 | bool "Embedded system" | |
1379 | select EXPERT | |
1380 | help | |
1381 | This option should be enabled if compiling the kernel for | |
1382 | an embedded system so certain expert options are available | |
1383 | for configuration. | |
1384 | ||
cdd6c482 | 1385 | config HAVE_PERF_EVENTS |
0793a61d | 1386 | bool |
018df72d MF |
1387 | help |
1388 | See tools/perf/design.txt for details. | |
0793a61d | 1389 | |
906010b2 PZ |
1390 | config PERF_USE_VMALLOC |
1391 | bool | |
1392 | help | |
1393 | See tools/perf/design.txt for details | |
1394 | ||
57c0c15b | 1395 | menu "Kernel Performance Events And Counters" |
0793a61d | 1396 | |
cdd6c482 | 1397 | config PERF_EVENTS |
57c0c15b | 1398 | bool "Kernel performance events and counters" |
392d65a9 | 1399 | default y if PROFILING |
cdd6c482 | 1400 | depends on HAVE_PERF_EVENTS |
4c59e467 | 1401 | select ANON_INODES |
e360adbe | 1402 | select IRQ_WORK |
0793a61d | 1403 | help |
57c0c15b IM |
1404 | Enable kernel support for various performance events provided |
1405 | by software and hardware. | |
0793a61d | 1406 | |
dd77038d | 1407 | Software events are supported either built-in or via the |
57c0c15b | 1408 | use of generic tracepoints. |
0793a61d | 1409 | |
57c0c15b IM |
1410 | Most modern CPUs support performance events via performance |
1411 | counter registers. These registers count the number of certain | |
0793a61d TG |
1412 | types of hw events: such as instructions executed, cachemisses |
1413 | suffered, or branches mis-predicted - without slowing down the | |
1414 | kernel or applications. These registers can also trigger interrupts | |
1415 | when a threshold number of events have passed - and can thus be | |
1416 | used to profile the code that runs on that CPU. | |
1417 | ||
57c0c15b | 1418 | The Linux Performance Event subsystem provides an abstraction of |
dd77038d | 1419 | these software and hardware event capabilities, available via a |
57c0c15b | 1420 | system call and used by the "perf" utility in tools/perf/. It |
0793a61d TG |
1421 | provides per task and per CPU counters, and it provides event |
1422 | capabilities on top of those. | |
1423 | ||
1424 | Say Y if unsure. | |
1425 | ||
906010b2 PZ |
1426 | config DEBUG_PERF_USE_VMALLOC |
1427 | default n | |
1428 | bool "Debug: use vmalloc to back perf mmap() buffers" | |
1429 | depends on PERF_EVENTS && DEBUG_KERNEL | |
1430 | select PERF_USE_VMALLOC | |
1431 | help | |
1432 | Use vmalloc memory to back perf mmap() buffers. | |
1433 | ||
1434 | Mostly useful for debugging the vmalloc code on platforms | |
1435 | that don't require it. | |
1436 | ||
1437 | Say N if unsure. | |
1438 | ||
0793a61d TG |
1439 | endmenu |
1440 | ||
f8891e5e CL |
1441 | config VM_EVENT_COUNTERS |
1442 | default y | |
6a108a14 | 1443 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
f8891e5e | 1444 | help |
2aea4fb6 PJ |
1445 | VM event counters are needed for event counts to be shown. |
1446 | This option allows the disabling of the VM event counters | |
6a108a14 | 1447 | on EXPERT systems. /proc/vmstat will only show page counts |
2aea4fb6 | 1448 | if VM event counters are disabled. |
f8891e5e | 1449 | |
3d137310 TP |
1450 | config PCI_QUIRKS |
1451 | default y | |
6a108a14 | 1452 | bool "Enable PCI quirk workarounds" if EXPERT |
61cfc7e4 | 1453 | depends on PCI |
3d137310 TP |
1454 | help |
1455 | This enables workarounds for various PCI chipset | |
1456 | bugs/quirks. Disable this only if your target machine is | |
1457 | unaffected by PCI quirks. | |
1458 | ||
41ecc55b CL |
1459 | config SLUB_DEBUG |
1460 | default y | |
6a108a14 | 1461 | bool "Enable SLUB debugging support" if EXPERT |
f6acb635 | 1462 | depends on SLUB && SYSFS |
41ecc55b CL |
1463 | help |
1464 | SLUB has extensive debug support features. Disabling these can | |
1465 | result in significant savings in code size. This also disables | |
1466 | SLUB sysfs support. /sys/slab will not exist and there will be | |
1467 | no support for cache validation etc. | |
1468 | ||
b943c460 RD |
1469 | config COMPAT_BRK |
1470 | bool "Disable heap randomization" | |
1471 | default y | |
1472 | help | |
1473 | Randomizing heap placement makes heap exploits harder, but it | |
1474 | also breaks ancient binaries (including anything libc5 based). | |
1475 | This option changes the bootup default to heap randomization | |
692105b8 | 1476 | disabled, and can be overridden at runtime by setting |
b943c460 RD |
1477 | /proc/sys/kernel/randomize_va_space to 2. |
1478 | ||
1479 | On non-ancient distros (post-2000 ones) N is usually a safe choice. | |
1480 | ||
81819f0f CL |
1481 | choice |
1482 | prompt "Choose SLAB allocator" | |
a0acd820 | 1483 | default SLUB |
81819f0f CL |
1484 | help |
1485 | This option allows to select a slab allocator. | |
1486 | ||
1487 | config SLAB | |
1488 | bool "SLAB" | |
1489 | help | |
1490 | The regular slab allocator that is established and known to work | |
34013886 | 1491 | well in all environments. It organizes cache hot objects in |
02f56210 | 1492 | per cpu and per node queues. |
81819f0f CL |
1493 | |
1494 | config SLUB | |
81819f0f CL |
1495 | bool "SLUB (Unqueued Allocator)" |
1496 | help | |
1497 | SLUB is a slab allocator that minimizes cache line usage | |
1498 | instead of managing queues of cached objects (SLAB approach). | |
1499 | Per cpu caching is realized using slabs of objects instead | |
1500 | of queues of objects. SLUB can use memory efficiently | |
02f56210 SA |
1501 | and has enhanced diagnostics. SLUB is the default choice for |
1502 | a slab allocator. | |
81819f0f CL |
1503 | |
1504 | config SLOB | |
6a108a14 | 1505 | depends on EXPERT |
81819f0f CL |
1506 | bool "SLOB (Simple Allocator)" |
1507 | help | |
37291458 MM |
1508 | SLOB replaces the stock allocator with a drastically simpler |
1509 | allocator. SLOB is generally more space efficient but | |
1510 | does not perform as well on large systems. | |
81819f0f CL |
1511 | |
1512 | endchoice | |
1513 | ||
ea637639 JZ |
1514 | config MMAP_ALLOW_UNINITIALIZED |
1515 | bool "Allow mmapped anonymous memory to be uninitialized" | |
6a108a14 | 1516 | depends on EXPERT && !MMU |
ea637639 JZ |
1517 | default n |
1518 | help | |
1519 | Normally, and according to the Linux spec, anonymous memory obtained | |
1520 | from mmap() has it's contents cleared before it is passed to | |
1521 | userspace. Enabling this config option allows you to request that | |
1522 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus | |
1523 | providing a huge performance boost. If this option is not enabled, | |
1524 | then the flag will be ignored. | |
1525 | ||
1526 | This is taken advantage of by uClibc's malloc(), and also by | |
1527 | ELF-FDPIC binfmt's brk and stack allocator. | |
1528 | ||
1529 | Because of the obvious security issues, this option should only be | |
1530 | enabled on embedded devices where you control what is run in | |
1531 | userspace. Since that isn't generally a problem on no-MMU systems, | |
1532 | it is normally safe to say Y here. | |
1533 | ||
1534 | See Documentation/nommu-mmap.txt for more information. | |
1535 | ||
125e5645 | 1536 | config PROFILING |
b309a294 | 1537 | bool "Profiling support" |
125e5645 MD |
1538 | help |
1539 | Say Y here to enable the extended profiling support mechanisms used | |
1540 | by profilers such as OProfile. | |
1541 | ||
5f87f112 IM |
1542 | # |
1543 | # Place an empty function call at each tracepoint site. Can be | |
1544 | # dynamically changed for a probe function. | |
1545 | # | |
97e1c18e | 1546 | config TRACEPOINTS |
5f87f112 | 1547 | bool |
97e1c18e | 1548 | |
fb32e03f MD |
1549 | source "arch/Kconfig" |
1550 | ||
1da177e4 LT |
1551 | endmenu # General setup |
1552 | ||
ee7e5516 DB |
1553 | config HAVE_GENERIC_DMA_COHERENT |
1554 | bool | |
1555 | default n | |
1556 | ||
158a9624 LT |
1557 | config SLABINFO |
1558 | bool | |
1559 | depends on PROC_FS | |
0f389ec6 | 1560 | depends on SLAB || SLUB_DEBUG |
158a9624 LT |
1561 | default y |
1562 | ||
ae81f9e3 CE |
1563 | config RT_MUTEXES |
1564 | boolean | |
ae81f9e3 | 1565 | |
1da177e4 LT |
1566 | config BASE_SMALL |
1567 | int | |
1568 | default 0 if BASE_FULL | |
1569 | default 1 if !BASE_FULL | |
1570 | ||
66da5733 | 1571 | menuconfig MODULES |
1da177e4 LT |
1572 | bool "Enable loadable module support" |
1573 | help | |
1574 | Kernel modules are small pieces of compiled code which can | |
1575 | be inserted in the running kernel, rather than being | |
1576 | permanently built into the kernel. You use the "modprobe" | |
1577 | tool to add (and sometimes remove) them. If you say Y here, | |
1578 | many parts of the kernel can be built as modules (by | |
1579 | answering M instead of Y where indicated): this is most | |
1580 | useful for infrequently used options which are not required | |
1581 | for booting. For more information, see the man pages for | |
1582 | modprobe, lsmod, modinfo, insmod and rmmod. | |
1583 | ||
1584 | If you say Y here, you will need to run "make | |
1585 | modules_install" to put the modules under /lib/modules/ | |
1586 | where modprobe can find them (you may need to be root to do | |
1587 | this). | |
1588 | ||
1589 | If unsure, say Y. | |
1590 | ||
0b0de144 RD |
1591 | if MODULES |
1592 | ||
826e4506 LT |
1593 | config MODULE_FORCE_LOAD |
1594 | bool "Forced module loading" | |
826e4506 LT |
1595 | default n |
1596 | help | |
91e37a79 RR |
1597 | Allow loading of modules without version information (ie. modprobe |
1598 | --force). Forced module loading sets the 'F' (forced) taint flag and | |
1599 | is usually a really bad idea. | |
826e4506 | 1600 | |
1da177e4 LT |
1601 | config MODULE_UNLOAD |
1602 | bool "Module unloading" | |
1da177e4 LT |
1603 | help |
1604 | Without this option you will not be able to unload any | |
1605 | modules (note that some modules may not be unloadable | |
f7f5b675 DV |
1606 | anyway), which makes your kernel smaller, faster |
1607 | and simpler. If unsure, say Y. | |
1da177e4 LT |
1608 | |
1609 | config MODULE_FORCE_UNLOAD | |
1610 | bool "Forced module unloading" | |
1611 | depends on MODULE_UNLOAD && EXPERIMENTAL | |
1612 | help | |
1613 | This option allows you to force a module to unload, even if the | |
1614 | kernel believes it is unsafe: the kernel will remove the module | |
1615 | without waiting for anyone to stop using it (using the -f option to | |
1616 | rmmod). This is mainly for kernel developers and desperate users. | |
1617 | If unsure, say N. | |
1618 | ||
1da177e4 | 1619 | config MODVERSIONS |
0d541643 | 1620 | bool "Module versioning support" |
1da177e4 LT |
1621 | help |
1622 | Usually, you have to use modules compiled with your kernel. | |
1623 | Saying Y here makes it sometimes possible to use modules | |
1624 | compiled for different kernels, by adding enough information | |
1625 | to the modules to (hopefully) spot any changes which would | |
1626 | make them incompatible with the kernel you are running. If | |
1627 | unsure, say N. | |
1628 | ||
1629 | config MODULE_SRCVERSION_ALL | |
1630 | bool "Source checksum for all modules" | |
1da177e4 LT |
1631 | help |
1632 | Modules which contain a MODULE_VERSION get an extra "srcversion" | |
1633 | field inserted into their modinfo section, which contains a | |
1634 | sum of the source files which made it. This helps maintainers | |
1635 | see exactly which source was used to build a module (since | |
1636 | others sometimes change the module source without updating | |
1637 | the version). With this option, such a "srcversion" field | |
1638 | will be created for all modules. If unsure, say N. | |
1639 | ||
106a4ee2 RR |
1640 | config MODULE_SIG |
1641 | bool "Module signature verification" | |
1642 | depends on MODULES | |
48ba2462 DH |
1643 | select KEYS |
1644 | select CRYPTO | |
1645 | select ASYMMETRIC_KEY_TYPE | |
1646 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE | |
1647 | select PUBLIC_KEY_ALGO_RSA | |
1648 | select ASN1 | |
1649 | select OID_REGISTRY | |
1650 | select X509_CERTIFICATE_PARSER | |
106a4ee2 RR |
1651 | help |
1652 | Check modules for valid signatures upon load: the signature | |
1653 | is simply appended to the module. For more information see | |
1654 | Documentation/module-signing.txt. | |
1655 | ||
ea0b6dcf DH |
1656 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
1657 | module DOES NOT get stripped after being signed. This includes the | |
1658 | debuginfo strip done by some packagers (such as rpmbuild) and | |
1659 | inclusion into an initramfs that wants the module size reduced. | |
1660 | ||
106a4ee2 RR |
1661 | config MODULE_SIG_FORCE |
1662 | bool "Require modules to be validly signed" | |
1663 | depends on MODULE_SIG | |
1664 | help | |
1665 | Reject unsigned modules or signed modules for which we don't have a | |
1666 | key. Without this, such modules will simply taint the kernel. | |
ea0b6dcf DH |
1667 | |
1668 | choice | |
1669 | prompt "Which hash algorithm should modules be signed with?" | |
1670 | depends on MODULE_SIG | |
1671 | help | |
1672 | This determines which sort of hashing algorithm will be used during | |
1673 | signature generation. This algorithm _must_ be built into the kernel | |
1674 | directly so that signature verification can take place. It is not | |
1675 | possible to load a signed module containing the algorithm to check | |
1676 | the signature on that module. | |
1677 | ||
1678 | config MODULE_SIG_SHA1 | |
1679 | bool "Sign modules with SHA-1" | |
1680 | select CRYPTO_SHA1 | |
1681 | ||
1682 | config MODULE_SIG_SHA224 | |
1683 | bool "Sign modules with SHA-224" | |
1684 | select CRYPTO_SHA256 | |
1685 | ||
1686 | config MODULE_SIG_SHA256 | |
1687 | bool "Sign modules with SHA-256" | |
1688 | select CRYPTO_SHA256 | |
1689 | ||
1690 | config MODULE_SIG_SHA384 | |
1691 | bool "Sign modules with SHA-384" | |
1692 | select CRYPTO_SHA512 | |
1693 | ||
1694 | config MODULE_SIG_SHA512 | |
1695 | bool "Sign modules with SHA-512" | |
1696 | select CRYPTO_SHA512 | |
1697 | ||
1698 | endchoice | |
1699 | ||
0b0de144 RD |
1700 | endif # MODULES |
1701 | ||
98a79d6a RR |
1702 | config INIT_ALL_POSSIBLE |
1703 | bool | |
1704 | help | |
5f054e31 RR |
1705 | Back when each arch used to define their own cpu_online_mask and |
1706 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask | |
98a79d6a RR |
1707 | with all 1s, and others with all 0s. When they were centralised, |
1708 | it was better to provide this option than to break all the archs | |
692105b8 | 1709 | and have several arch maintainers pursuing me down dark alleys. |
98a79d6a | 1710 | |
1da177e4 LT |
1711 | config STOP_MACHINE |
1712 | bool | |
1713 | default y | |
1714 | depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU | |
1715 | help | |
1716 | Need stop_machine() primitive. | |
3a65dfe8 | 1717 | |
3a65dfe8 | 1718 | source "block/Kconfig" |
e98c3202 AK |
1719 | |
1720 | config PREEMPT_NOTIFIERS | |
1721 | bool | |
e260be67 | 1722 | |
16295bec SK |
1723 | config PADATA |
1724 | depends on SMP | |
1725 | bool | |
1726 | ||
754b7b63 AK |
1727 | # Can be selected by architectures with broken toolchains |
1728 | # that get confused by correct const<->read_only section | |
1729 | # mappings | |
1730 | config BROKEN_RODATA | |
1731 | bool | |
1732 | ||
4520c6a4 DH |
1733 | config ASN1 |
1734 | tristate | |
1735 | help | |
1736 | Build a simple ASN.1 grammar compiler that produces a bytecode output | |
1737 | that can be interpreted by the ASN.1 stream decoder and used to | |
1738 | inform it as to what tags are to be expected in a stream and what | |
1739 | functions to call on what tags. | |
1740 | ||
6beb0009 | 1741 | source "kernel/Kconfig.locks" |